Your FREE Therapist Multiple-Choice (TMC) Exam Practice Test 2026 – 280+ Q&A

TMC Exam Practice Questions

1. An arterial blood gas shows pH 7.30, PaCO2 58 mm Hg, and HCO3 27 mEq/L. Which acid-base disorder does this best represent?
   • Acute metabolic acidosis
   • Acute respiratory alkalosis
   • Acute metabolic alkalosis
   • Acute respiratory acidosis

   Correct answer: Acute respiratory acidosis

   Acute respiratory acidosis is correct because the pH is below 7.35 (acidemia) while the PaCO2 is elevated above 45 mm Hg, identifying the respiratory system as the primary cause; the nearly normal HCO3 indicates the kidneys have not yet compensated.

2. A blood gas reveals pH 7.52, PaCO2 28 mm Hg, and HCO3 23 mEq/L. What is the correct interpretation?
   • Acute metabolic alkalosis
   • Acute respiratory alkalosis
   • Acute respiratory acidosis
   • Acute metabolic acidosis

   Correct answer: Acute respiratory alkalosis

   Acute respiratory alkalosis is the answer because the pH is above 7.45 (alkalemia) and the PaCO2 is below 35 mm Hg, indicating excessive carbon dioxide elimination; the normal bicarbonate confirms the disturbance is respiratory and uncompensated.

3. An ABG shows pH 7.29, PaCO2 33 mm Hg, and HCO3 16 mEq/L. Which disorder is present?
   • Respiratory acidosis
   • Respiratory alkalosis
   • Metabolic acidosis
   • Metabolic alkalosis

   Correct answer: Metabolic acidosis

   Metabolic acidosis is correct because the low pH paired with a low bicarbonate (below 22 mEq/L) identifies a metabolic origin; the slightly low PaCO2 reflects respiratory compensation through hyperventilation.

4. A patient's blood gas shows pH 7.50, PaCO2 46 mm Hg, and HCO3 34 mEq/L. What does this represent?
   • Metabolic acidosis
   • Metabolic alkalosis
   • Respiratory alkalosis
   • Respiratory acidosis

   Correct answer: Metabolic alkalosis

   Metabolic alkalosis is the answer because the elevated pH with a high bicarbonate (above 26 mEq/L) points to a metabolic cause; the mildly elevated PaCO2 indicates respiratory compensation through hypoventilation.

5. An ABG reveals pH 7.37, PaCO2 60 mm Hg, and HCO3 35 mEq/L in a patient with chronic COPD. How should this be classified?
   • Acute respiratory acidosis
   • Fully compensated respiratory acidosis
   • Uncompensated metabolic alkalosis
   • Mixed respiratory and metabolic acidosis

   Correct answer: Fully compensated respiratory acidosis

   Fully compensated respiratory acidosis is correct because the pH has returned to the normal range while both the PaCO2 and HCO3 remain markedly abnormal; the elevated bicarbonate shows the kidneys have fully offset the chronic CO2 retention.

6. While interpreting an arterial blood gas, which value should the therapist assess first to determine whether acidemia or alkalemia is present?
   • pH
   • PaCO2
   • HCO3
   • Base excess

   Correct answer: pH

   The pH should be evaluated first because it directly indicates whether the blood is acidemic (below 7.35) or alkalemic (above 7.45), establishing the direction of the disturbance before the respiratory and metabolic components are examined.

7. After establishing that a blood gas shows acidemia, which two values does the therapist compare to identify whether the cause is respiratory or metabolic?
   • pH and base excess
   • PaO2 and SaO2
   • PaO2 and PaCO2
   • PaCO2 and HCO3

   Correct answer: PaCO2 and HCO3

   Comparing PaCO2 and HCO3 is correct because PaCO2 reflects the respiratory contribution and HCO3 reflects the metabolic contribution; identifying which one moves in the same direction as the pH disturbance reveals the primary cause.

8. A patient with diabetic ketoacidosis is most likely to demonstrate which arterial blood gas pattern?
   • High pH with high HCO3
   • Normal pH with high PaCO2
   • Low pH with low HCO3
   • High pH with low PaCO2

   Correct answer: Low pH with low HCO3

   Low pH with low HCO3 is correct because ketoacid accumulation consumes bicarbonate, producing a metabolic acidosis; this is the hallmark blood gas finding in diabetic ketoacidosis.

9. A patient breathing room air has a PaO2 of 60 mm Hg. What is the calculated P/F ratio?
   • 286
   • 210
   • 150
   • 60

   Correct answer: 286

   A P/F ratio of 286 is correct because the PaO2 of 60 is divided by the FiO2 of 0.21 (room air), yielding 286; this value places the patient just above the mild hypoxemia threshold used for ARDS staging.

10. A mechanically ventilated patient has a PaO2 of 80 mm Hg on an FiO2 of 0.80. According to the Berlin definition, this P/F ratio of 100 indicates which severity of ARDS?
    • No ARDS
    • Severe ARDS
    • Mild ARDS
    • Moderate ARDS

    Correct answer: Severe ARDS

    Severe ARDS is correct because a P/F ratio of 100 or less (with PEEP at least 5 cm H2O) defines the severe category; the PaO2 of 80 divided by an FiO2 of 0.80 equals a P/F ratio of 100.

11. The alveolar-arterial oxygen gradient is widened. Which condition does this finding most strongly suggest?
    • Hypoventilation from oversedation
    • High altitude exposure
    • A gas exchange problem such as V/Q mismatch
    • A blood gas analyzer calibration error

    Correct answer: A gas exchange problem such as V/Q mismatch

    A gas exchange problem such as V/Q mismatch is correct because a widened A-a gradient indicates oxygen is not transferring normally from alveoli to blood; pure hypoventilation typically leaves the gradient normal.

12. A patient breathing room air has a calculated alveolar PO2 of 100 mm Hg and a measured PaO2 of 70 mm Hg. What is the alveolar-arterial gradient?
    • 30 mm Hg
    • 170 mm Hg
    • 100 mm Hg
    • 70 mm Hg

    Correct answer: 30 mm Hg

    A gradient of 30 mm Hg is correct because the A-a gradient equals alveolar PO2 minus arterial PaO2 (100 − 70 = 30 mm Hg); this widened value suggests impaired oxygen transfer rather than simple hypoventilation.

13. A patient has a total minute ventilation of 8 L/min but a large portion is dead space ventilation. Which physiologic consequence is most expected?
    • A falling PaCO2 with hyperventilation
    • A rising PaCO2 despite adequate total ventilation
    • An increase in alveolar oxygen tension
    • A decrease in physiologic shunt

    Correct answer: A rising PaCO2 despite adequate total ventilation

    A rising PaCO2 despite adequate total ventilation is correct because dead space ventilation does not participate in gas exchange; when dead space increases, effective alveolar ventilation falls and CO2 accumulates.

14. A neonate on mechanical ventilation has a mean airway pressure of 15 cm H2O, an FiO2 of 1.0, and a PaO2 of 50 mm Hg. The oxygenation index is approximately:
    • 7.5
    • 15
    • 3.3
    • 30

    Correct answer: 30

    An oxygenation index of 30 is correct because OI equals mean airway pressure × FiO2 × 100, divided by PaO2 ((15 × 1.0 × 100) ÷ 50 = 30); a value of 30 reflects severe respiratory failure often used in ECMO decision-making.

15. A patient breathes at a rate of 12 breaths/min with a tidal volume of 500 mL. What is the minute ventilation?
    • 12 L/min
    • 60 L/min
    • 6 L/min
    • 5 L/min

    Correct answer: 6 L/min

    A minute ventilation of 6 L/min is correct because minute ventilation equals respiratory rate × tidal volume (12 × 500 mL = 6,000 mL = 6 L); this is within the normal resting range.

16. A bedside vital capacity measurement of 8 mL/kg is obtained during a weaning assessment. How should the therapist interpret this value?
    • It is below the threshold generally considered adequate for weaning
    • It indicates adequate ventilatory reserve for extubation
    • It confirms the presence of obstructive lung disease
    • It indicates oxygenation is adequate

    Correct answer: It is below the threshold generally considered adequate for weaning

    It is below the threshold generally considered adequate for weaning because a vital capacity of at least 10-15 mL/kg is the commonly cited target; 8 mL/kg suggests insufficient ventilatory reserve to support spontaneous breathing.

17. A maximum inspiratory pressure of -15 cm H2O is measured in a patient being assessed for ventilator weaning. What does this value indicate?
    • Adequate inspiratory muscle strength for weaning
    • Inadequate inspiratory muscle strength for weaning
    • A normal value requiring no further action
    • An equipment malfunction

    Correct answer: Inadequate inspiratory muscle strength for weaning

    Inadequate inspiratory muscle strength for weaning is correct because a MIP more negative than -20 to -30 cm H2O is generally needed; -15 cm H2O reflects weak inspiratory effort and predicts a poor weaning outcome.

18. During a measurement of maximum inspiratory pressure, the therapist should instruct the patient to:
    • Exhale forcefully against a closed valve
    • Inhale as forcefully as possible against an occluded airway
    • Inhale maximally then hold the breath
    • Breathe normally for one minute

    Correct answer: Inhale as forcefully as possible against an occluded airway

    Inhaling as forcefully as possible against an occluded airway is correct because MIP measures the negative pressure generated by inspiratory muscles against occlusion; this isolates inspiratory muscle strength.

19. A ventilated patient has a peak inspiratory pressure of 40 cm H2O and a plateau pressure of 22 cm H2O. The rising peak with a stable plateau most likely reflects:
    • Decreased lung compliance
    • Worsening pulmonary edema
    • Increased airway resistance
    • Tension pneumothorax

    Correct answer: Increased airway resistance

    Increased airway resistance is correct because a high peak pressure with a normal plateau pressure points to a resistive problem such as bronchospasm or secretions; compliance problems would also elevate the plateau pressure.

20. During an inspiratory hold maneuver on a volume-controlled breath, the plateau pressure rises to 35 cm H2O. What does this measurement primarily assess?
    • Airway resistance
    • Static lung compliance
    • Auto-PEEP magnitude
    • Dead space volume

    Correct answer: Static lung compliance

    Static lung compliance is correct because the plateau pressure measured during an inspiratory hold reflects the pressure needed to distend the lungs and chest wall at zero flow, which determines compliance.

21. A ventilated COPD patient has expiratory flow that fails to return to zero before the next breath. An expiratory hold reveals a pressure of 8 cm H2O above the set PEEP. This finding indicates:
    • A leak in the circuit
    • Auto-PEEP from air trapping
    • Inadequate humidification
    • A disconnected exhalation valve

    Correct answer: Auto-PEEP from air trapping

    Auto-PEEP from air trapping is correct because incomplete exhalation causes gas to remain in the lungs, raising end-expiratory pressure; the expiratory hold maneuver quantifies this trapped pressure above the set PEEP.

22. A firefighter rescued from a structure fire has a pulse oximeter reading of 99% but reports headache and confusion. A CO-oximetry analysis is performed primarily to detect:
    • Carboxyhemoglobin
    • Methemoglobin
    • Total hemoglobin
    • Plasma bicarbonate

    Correct answer: Carboxyhemoglobin

    Carboxyhemoglobin is correct because CO-oximetry directly measures abnormal hemoglobin species; carbon monoxide poisoning is suspected here since the standard pulse oximeter cannot distinguish carboxyhemoglobin from oxyhemoglobin and reads falsely normal.

23. A patient who received a topical anesthetic before bronchoscopy develops cyanosis and a pulse oximetry reading stuck near 85% despite high-flow oxygen. CO-oximetry would most likely reveal an elevated level of:
    • Carboxyhemoglobin
    • Oxyhemoglobin
    • Deoxyhemoglobin
    • Methemoglobin

    Correct answer: Methemoglobin

    Methemoglobin is correct because certain topical anesthetics can induce methemoglobinemia, which causes cyanosis and a characteristic pulse oximetry reading that plateaus around 85% regardless of supplemental oxygen.

24. Methemoglobin differs from normal hemoglobin in that it:
    • Carries oxygen more efficiently
    • Binds carbon dioxide preferentially
    • Contains iron in the ferric state and cannot bind oxygen
    • Is produced only in the lungs

    Correct answer: Contains iron in the ferric state and cannot bind oxygen

    Containing iron in the ferric state and being unable to bind oxygen is correct because methemoglobin forms when hemoglobin iron is oxidized from ferrous to ferric, which prevents normal oxygen transport and reduces oxygen delivery.

25. A capnography waveform shows a steadily rising baseline that does not return to zero between breaths. This pattern most likely indicates:
    • Hyperventilation
    • Esophageal intubation
    • Cardiac arrest
    • Rebreathing of exhaled CO2

    Correct answer: Rebreathing of exhaled CO2

    Rebreathing of exhaled CO2 is correct because an elevated baseline that fails to reach zero signifies inspired gas containing CO2, often from an incompetent expiratory valve or inadequate fresh gas flow.

26. Immediately after endotracheal intubation, continuous capnography shows a normal square waveform with end-tidal CO2 of 38 mm Hg. This finding confirms:
    • Correct placement of the tube in the trachea
    • Esophageal placement of the tube
    • Right mainstem intubation
    • An adequate cuff seal

    Correct answer: Correct placement of the tube in the trachea

    Correct placement of the tube in the trachea is correct because sustained exhaled CO2 producing a normal waveform confirms the tube is ventilating the lungs; esophageal placement yields little or no CO2.

27. During CPR, a sudden rise in end-tidal CO2 from 12 to 35 mm Hg most likely indicates:
    • Return of spontaneous circulation
    • Tube dislodgement
    • Worsening hypoventilation
    • Esophageal intubation

    Correct answer: Return of spontaneous circulation

    Return of spontaneous circulation is correct because restored cardiac output increases pulmonary blood flow and CO2 delivery to the lungs, producing an abrupt rise in end-tidal CO2 during resuscitation.

28. A pulse oximeter reads 88% on a patient with cold, poorly perfused fingers and a weak plethysmograph signal. The most appropriate first action is to:
    • Improve the signal by warming the site or repositioning the probe
    • Increase the FiO2 immediately
    • Document the reading as accurate
    • Discontinue oxygen therapy

    Correct answer: Improve the signal by warming the site or repositioning the probe

    Improving the signal by warming the site or repositioning the probe is correct because poor perfusion produces an unreliable pulse oximetry signal; the reading must be validated before treatment decisions are based on it.

29. Pulse oximetry provides which measurement?
    • Functional oxygen saturation of hemoglobin
    • Partial pressure of arterial oxygen
    • Arterial carbon dioxide tension
    • Total hemoglobin concentration

    Correct answer: Functional oxygen saturation of hemoglobin

    Functional oxygen saturation of hemoglobin is correct because a pulse oximeter estimates the percentage of hemoglobin saturated with oxygen using light absorption, not the dissolved oxygen tension or hemoglobin content.

30. Spirometry shows an FEV1/FVC ratio of 0.60 with a reduced FEV1. This pattern is most consistent with:
    • A restrictive disorder
    • A normal study
    • A mixed neuromuscular disorder
    • An obstructive disorder

    Correct answer: An obstructive disorder

    An obstructive disorder is correct because a reduced FEV1/FVC ratio below 0.70 indicates airflow limitation characteristic of obstruction such as COPD or asthma; restrictive disease usually preserves or raises this ratio.

31. A spirometry report shows a normal FEV1/FVC ratio but a markedly reduced FVC and total lung capacity. This pattern best indicates:
    • An obstructive ventilatory defect
    • A restrictive ventilatory defect
    • Reversible bronchospasm
    • Upper airway obstruction

    Correct answer: A restrictive ventilatory defect

    A restrictive ventilatory defect is correct because reduced lung volumes with a preserved or elevated FEV1/FVC ratio reflect difficulty fully expanding the lungs rather than airflow limitation.

32. After administering a bronchodilator during spirometry, the FEV1 improves by 15% and 250 mL. This response indicates:
    • No clinically significant change
    • A restrictive process
    • Significant reversibility of airflow obstruction
    • Poor patient effort

    Correct answer: Significant reversibility of airflow obstruction

    Significant reversibility of airflow obstruction is correct because an increase in FEV1 of at least 12% and 200 mL after a bronchodilator demonstrates reversible obstruction, a feature commonly seen in asthma.

33. A patient with pulmonary fibrosis is most likely to show which spirometry and diffusion pattern?
    • Increased lung volumes with normal DLCO
    • Normal volumes with elevated DLCO
    • Reduced lung volumes with reduced DLCO
    • Obstructive curve with normal volumes

    Correct answer: Reduced lung volumes with reduced DLCO

    Reduced lung volumes with reduced DLCO is correct because fibrosis restricts lung expansion and thickens the alveolar-capillary membrane, lowering both measured volumes and the diffusing capacity for carbon monoxide.

34. A reduced DLCO with otherwise normal spirometry in a patient with shortness of breath would be most consistent with:
    • Asthma
    • Pulmonary vascular disease
    • Vocal cord dysfunction
    • Obesity hypoventilation

    Correct answer: Pulmonary vascular disease

    Pulmonary vascular disease is correct because conditions such as pulmonary hypertension impair gas transfer across the alveolar-capillary membrane, lowering DLCO even when airflow and volumes remain normal.

35. A sleep study reports an apnea-hypopnea index of 32 events per hour. How should this be categorized?
    • Normal
    • Severe obstructive sleep apnea
    • Mild obstructive sleep apnea
    • Moderate obstructive sleep apnea

    Correct answer: Severe obstructive sleep apnea

    Severe obstructive sleep apnea is correct because an AHI of 30 or more events per hour defines the severe category; this finding typically supports a recommendation for positive airway pressure therapy.

36. A patient completes a 6-minute walk test and desaturates from 95% to 84% with exertion. The most appropriate recommendation is to:
    • Stop all physical activity permanently
    • Increase the patient's diuretic dose
    • Evaluate the need for ambulatory oxygen therapy
    • Order immediate intubation

    Correct answer: Evaluate the need for ambulatory oxygen therapy

    Evaluating the need for ambulatory oxygen therapy is correct because significant exertional desaturation during the 6-minute walk test indicates the patient may require supplemental oxygen during activity to maintain adequate saturation.

37. The 6-minute walk test is most commonly used to assess:
    • Functional exercise capacity and exertional oxygenation
    • Resting arterial blood gases
    • Maximum voluntary ventilation
    • Static lung compliance

    Correct answer: Functional exercise capacity and exertional oxygenation

    Functional exercise capacity and exertional oxygenation is correct because the 6-minute walk test measures how far a patient can walk and whether saturation falls with exertion, providing a practical assessment of functional status.

38. An asthmatic patient's personal best peak expiratory flow is 500 L/min, and today's reading is 280 L/min (56% of best). According to standard asthma action plans, this places the patient in which zone?
    • Green zone
    • Yellow zone
    • Red zone
    • Blue zone

    Correct answer: Yellow zone

    The yellow zone is correct because a peak expiratory flow of 56% of personal best (280 of 500 L/min) falls between 50% and 79%, signaling caution and a need to follow the action-plan steps. A reading below 50% would be the red zone, and 80% or above would be the green zone.

39. When coaching a patient to perform a peak expiratory flow measurement, the therapist should instruct the patient to:
    • Exhale slowly and completely over six seconds
    • Breathe normally into the device
    • Hold the breath for ten seconds before exhaling
    • Inhale fully then blow out as hard and fast as possible

    Correct answer: Inhale fully then blow out as hard and fast as possible

    Inhaling fully then blowing out as hard and fast as possible is correct because peak expiratory flow captures the maximum speed of a forced exhalation, which requires a full inspiration followed by a rapid, forceful blast.

40. During an airway assessment, only the soft palate and base of the uvula are visible. This corresponds to which Mallampati class?
    • Class I
    • Class II
    • Class IV
    • Class III

    Correct answer: Class III

    Class III is correct because the Mallampati system grades airway visibility, and seeing only the soft palate and base of the uvula corresponds to class III, which predicts a potentially difficult intubation.

41. A high Mallampati classification is used primarily to predict:
    • The severity of bronchospasm
    • The presence of pulmonary edema
    • The degree of hypoxemia
    • The likelihood of a difficult intubation

    Correct answer: The likelihood of a difficult intubation

    The likelihood of a difficult intubation is correct because the Mallampati classification grades how much of the oropharyngeal structures are visible, and higher classes correlate with greater difficulty in visualizing the glottis during intubation.

42. A 12-lead ECG shows a regular rhythm at 150 beats/min with no identifiable P waves and a narrow QRS. This is most consistent with:
    • Supraventricular tachycardia
    • Sinus tachycardia
    • Ventricular fibrillation
    • Third-degree heart block

    Correct answer: Supraventricular tachycardia

    Supraventricular tachycardia is correct because a rapid, regular, narrow-complex rhythm without visible P waves originates above the ventricles; sinus tachycardia would show clear P waves preceding each QRS.

43. On a rhythm strip, the therapist observes a chaotic, irregular baseline with no organized QRS complexes in a pulseless patient. This rhythm is:
    • Atrial fibrillation
    • Asystole
    • Ventricular fibrillation
    • First-degree heart block

    Correct answer: Ventricular fibrillation

    Ventricular fibrillation is correct because the disorganized, irregular waveform without identifiable QRS complexes in a pulseless patient represents chaotic ventricular activity requiring immediate defibrillation.

44. A newborn at one minute of life has a heart rate of 90, slow irregular respirations, some flexion of extremities, a grimace to stimulation, and a blue body with pink trunk. What is the approximate Apgar score?
    • 3
    • 7
    • 9
    • 5

    Correct answer: 5

    A score of 5 is correct because heart rate below 100 earns 1, slow irregular respirations earn 1, some flexion earns 1, grimace earns 1, and acrocyanosis earns 1, totaling 5; this indicates the infant needs continued support and reassessment.

45. Each of the five Apgar components is scored from 0 to 2. Which set of parameters is assessed?
    • Heart rate, blood pressure, temperature, color, tone
    • Respiratory rate, gestational age, weight, tone, color
    • Heart rate, respiratory effort, muscle tone, reflex irritability, color
    • Oxygen saturation, heart rate, glucose, tone, color

    Correct answer: Heart rate, respiratory effort, muscle tone, reflex irritability, color

    Heart rate, respiratory effort, muscle tone, reflex irritability, and color is correct because these are the five components of the Apgar score used to rapidly assess a newborn's condition at one and five minutes of life.

46. An amniotic fluid analysis reports a lecithin/sphingomyelin ratio of 1.5:1. What does this value most likely indicate about the fetus?
    • Immature lungs with increased risk of respiratory distress syndrome
    • Mature lungs with low risk of respiratory distress
    • Adequate surfactant production
    • Postmature gestation

    Correct answer: Immature lungs with increased risk of respiratory distress syndrome

    Immature lungs with increased risk of respiratory distress syndrome is correct because an L/S ratio below 2:1 suggests insufficient surfactant production; a ratio of at least 2:1 generally indicates fetal lung maturity.

47. A spontaneously breathing patient on minimal support has a respiratory rate of 32 and a tidal volume of 0.3 L. What is the rapid shallow breathing index?
    • About 11
    • About 107
    • About 96
    • About 320

    Correct answer: About 107

    About 107 is correct because the RSBI equals respiratory rate divided by tidal volume in liters (32 ÷ 0.3 ≈ 107); a value above 105 predicts a high likelihood of weaning failure.

48. A rapid shallow breathing index of 80 is calculated during a weaning assessment. How should this be interpreted?
    • It predicts weaning failure
    • It indicates the patient cannot be assessed
    • It predicts successful weaning
    • It reflects an oxygenation problem

    Correct answer: It predicts successful weaning

    It predicts successful weaning because an RSBI below 105 breaths/min/L is associated with a favorable likelihood of tolerating extubation; the lower value reflects breathing that is not excessively rapid or shallow.

49. Before initiating a spontaneous breathing trial, which patient finding would most appropriately delay the trial?
    • FiO2 of 0.40 with adequate saturation
    • An RSBI of 70
    • Hemodynamic instability requiring escalating vasopressors
    • A resolved underlying cause of respiratory failure

    Correct answer: Hemodynamic instability requiring escalating vasopressors

    Hemodynamic instability requiring escalating vasopressors is correct because a spontaneous breathing trial should only proceed once the patient is hemodynamically stable; ongoing instability indicates the patient is not ready for ventilator liberation.

50. A patient tolerates a 30-minute spontaneous breathing trial on a T-piece with stable vital signs and adequate gas exchange. The most appropriate recommendation is to:
    • Increase the PEEP
    • Initiate neuromuscular blockade
    • Recommend extubation
    • Return to full ventilatory support indefinitely

    Correct answer: Recommend extubation

    Recommending extubation is correct because successful completion of a spontaneous breathing trial with stable parameters indicates the patient can likely sustain spontaneous breathing without the artificial airway.

51. Which combination of weaning parameters would most strongly support a patient's readiness for ventilator liberation?
    • Vital capacity 5 mL/kg and MIP -10 cm H2O
    • RSBI 130 and FiO2 0.70
    • Minute ventilation 18 L/min and PEEP 12 cm H2O
    • Vital capacity 15 mL/kg, MIP -30 cm H2O, and RSBI 80

    Correct answer: Vital capacity 15 mL/kg, MIP -30 cm H2O, and RSBI 80

    Vital capacity 15 mL/kg, MIP -30 cm H2O, and RSBI 80 is correct because each value meets accepted weaning thresholds, indicating adequate ventilatory reserve, inspiratory strength, and breathing pattern to support liberation.

52. An ABG shows pH 7.34, PaCO2 70 mm Hg, and HCO3 36 mEq/L in a long-standing COPD patient who is alert and at baseline. The most appropriate immediate action is to:
    • Aggressively increase FiO2 to normalize PaO2
    • Initiate emergent intubation
    • Maintain current management and target the patient's baseline saturation
    • Administer sodium bicarbonate

    Correct answer: Maintain current management and target the patient's baseline saturation

    Maintaining current management and targeting the patient's baseline saturation is correct because this represents chronic compensated respiratory acidosis at baseline; the patient is stable, and overcorrecting oxygenation could worsen CO2 retention.

53. A patient with an acute asthma exacerbation initially had a low PaCO2 from hyperventilation. The PaCO2 is now 'normalizing' to 42 mm Hg as the patient tires. This change should be interpreted as:
    • An ominous sign of impending respiratory failure
    • A reassuring sign of improvement
    • Evidence of metabolic compensation
    • A laboratory error

    Correct answer: An ominous sign of impending respiratory failure

    An ominous sign of impending respiratory failure is correct because a normalizing PaCO2 in a severe asthma attack reflects worsening fatigue and falling minute ventilation; the apparently normal value signals the patient can no longer maintain hyperventilation.

54. A patient with prolonged vomiting and nasogastric suction is most likely to develop which acid-base disturbance?
    • Metabolic acidosis
    • Respiratory acidosis
    • Respiratory alkalosis
    • Metabolic alkalosis

    Correct answer: Metabolic alkalosis

    Metabolic alkalosis is correct because loss of gastric acid through vomiting and suctioning depletes hydrogen and chloride ions, raising the bicarbonate and producing an elevated pH.

55. A patient experiencing an anxiety-driven panic attack with rapid breathing most likely demonstrates which blood gas pattern?
    • Low pH with high PaCO2
    • Low pH with low HCO3
    • High pH with high HCO3
    • High pH with low PaCO2

    Correct answer: High pH with low PaCO2

    High pH with low PaCO2 is correct because hyperventilation blows off carbon dioxide, producing respiratory alkalosis; this is the characteristic acute response to anxiety-driven rapid breathing.

56. A blood gas shows pH 7.20, PaCO2 55 mm Hg, and HCO3 16 mEq/L. This combination is best described as:
    • A combined respiratory and metabolic acidosis
    • Compensated respiratory acidosis
    • Compensated metabolic acidosis
    • Respiratory alkalosis

    Correct answer: A combined respiratory and metabolic acidosis

    A combined respiratory and metabolic acidosis is correct because both the elevated PaCO2 and the low HCO3 drive the pH down simultaneously; neither system is compensating, indicating two coexisting acidotic processes.

57. A patient breathing 50% oxygen has a PaO2 of 250 mm Hg. What is the P/F ratio, and how should oxygenation be characterized?
    • 250, indicating moderate ARDS
    • 125, indicating severe ARDS
    • 119, indicating mild ARDS
    • 500, indicating normal oxygenation

    Correct answer: 500, indicating normal oxygenation

    A P/F ratio of 500 is correct because the PaO2 of 250 divided by an FiO2 of 0.50 equals 500, which is well above the threshold for ARDS and reflects adequate gas exchange.

58. A widened A-a gradient that fully corrects with the administration of 100% oxygen is most consistent with which mechanism of hypoxemia?
    • Ventilation-perfusion mismatch
    • Anatomic right-to-left shunt
    • Reduced inspired oxygen
    • Pure hypoventilation

    Correct answer: Ventilation-perfusion mismatch

    Ventilation-perfusion mismatch is correct because hypoxemia from V/Q mismatch responds well to supplemental oxygen, correcting the gradient; a true shunt would not correct fully even on 100% oxygen.

59. A ventilated patient develops a sudden increase in dead space ventilation along with a falling end-tidal CO2 and rising PaCO2. This combination should prompt evaluation for:
    • Pulmonary embolism
    • Bronchospasm
    • Excess secretions
    • Cuff leak

    Correct answer: Pulmonary embolism

    Pulmonary embolism is correct because an embolus blocks pulmonary perfusion to ventilated alveoli, increasing dead space; this produces a widening gap between PaCO2 and the falling end-tidal CO2.

60. A patient's tidal volume is 600 mL and estimated dead space is 150 mL at a rate of 10 breaths/min. What is the approximate alveolar minute ventilation?
    • 6.0 L/min
    • 1.5 L/min
    • 4.5 L/min
    • 7.5 L/min

    Correct answer: 4.5 L/min

    4.5 L/min is correct because alveolar ventilation uses only the gas reaching the alveoli: tidal volume minus dead space (600 − 150 = 450 mL) multiplied by the rate of 10, yielding 450 × 10 = 4,500 mL = 4.5 L/min.

61. A vital capacity maneuver requires the patient to:
    • Inhale maximally and then exhale completely
    • Breathe normally for one minute
    • Exhale forcefully for the first second only
    • Hold the breath against an occlusion

    Correct answer: Inhale maximally and then exhale completely

    Inhaling maximally and then exhaling completely is correct because vital capacity is the total volume of air that can be exhaled after a maximal inspiration, requiring a full inhalation followed by a complete exhalation.

62. During an inspiratory hold maneuver, the difference between the peak inspiratory pressure and the plateau pressure primarily reflects:
    • Static compliance
    • Auto-PEEP
    • Airway resistance
    • Functional residual capacity

    Correct answer: Airway resistance

    Airway resistance is correct because the gap between peak and plateau pressures represents the pressure dissipated overcoming resistance to gas flow through the airways and tube; the plateau alone reflects compliance.

63. A ventilated patient has a worsening peak pressure of 45 cm H2O with a plateau pressure now also elevated to 38 cm H2O. This pattern indicates:
    • A purely resistive problem
    • A circuit leak
    • Decreased lung compliance
    • Auto-PEEP only

    Correct answer: Decreased lung compliance

    Decreased lung compliance is correct because when both the peak and plateau pressures rise together, the lungs have become stiffer, as seen with pulmonary edema, ARDS, or pneumothorax.

64. Auto-PEEP in a mechanically ventilated COPD patient can be reduced by:
    • Increasing the respiratory rate
    • Decreasing expiratory time
    • Increasing the tidal volume
    • Allowing more time for exhalation

    Correct answer: Allowing more time for exhalation

    Allowing more time for exhalation is correct because auto-PEEP results from incomplete exhalation; lengthening expiratory time, often by lowering the rate or increasing inspiratory flow, lets the lungs empty more fully.

65. A CO-oximetry analysis is preferred over standard pulse oximetry in a carbon monoxide poisoning victim because CO-oximetry can:
    • Measure the PaCO2 directly
    • Calculate the A-a gradient
    • Distinguish among multiple hemoglobin species including carboxyhemoglobin
    • Estimate cardiac output

    Correct answer: Distinguish among multiple hemoglobin species including carboxyhemoglobin

    Distinguishing among multiple hemoglobin species including carboxyhemoglobin is correct because CO-oximetry uses multiple wavelengths to quantify oxyhemoglobin, carboxyhemoglobin, and methemoglobin, unlike a standard two-wavelength pulse oximeter.

66. A patient with carbon monoxide poisoning typically has which combination of findings?
    • Low SaO2 measured by arterial blood gas calculation and low PaO2
    • Normal PaO2 with an elevated carboxyhemoglobin and reduced oxygen content
    • Elevated PaO2 with low carboxyhemoglobin
    • High methemoglobin with normal carboxyhemoglobin

    Correct answer: Normal PaO2 with an elevated carboxyhemoglobin and reduced oxygen content

    Normal PaO2 with an elevated carboxyhemoglobin and reduced oxygen content is correct because carbon monoxide does not affect dissolved oxygen tension but occupies hemoglobin binding sites, lowering the oxygen-carrying capacity despite a normal PaO2.

67. A capnography waveform that loses its normal alveolar plateau and shows a slurred, shark-fin upstroke is most consistent with:
    • Hyperventilation
    • Bronchospasm or airflow obstruction
    • Hypothermia
    • Sensor disconnection

    Correct answer: Bronchospasm or airflow obstruction

    Bronchospasm or airflow obstruction is correct because uneven alveolar emptying from obstructed airways produces a sloped, shark-fin shape replacing the normal square plateau on the capnogram.

68. A sudden drop of the end-tidal CO2 waveform to zero in an intubated patient most urgently suggests:
    • Tube disconnection, dislodgement, or obstruction
    • Improved cardiac output
    • Hypoventilation
    • Metabolic alkalosis

    Correct answer: Tube disconnection, dislodgement, or obstruction

    Tube disconnection, dislodgement, or obstruction is correct because an abrupt loss of all exhaled CO2 indicates ventilation has stopped reaching the lungs, requiring immediate assessment of the airway and circuit.

69. A patient with severe anemia (hemoglobin 6 g/dL) may have a normal pulse oximetry reading because pulse oximetry measures:
    • The total oxygen content of blood
    • The percentage saturation of available hemoglobin, not the amount of hemoglobin
    • The dissolved oxygen in plasma
    • The cardiac output

    Correct answer: The percentage saturation of available hemoglobin, not the amount of hemoglobin

    The percentage saturation of available hemoglobin, not the amount of hemoglobin is correct because pulse oximetry reports what fraction of present hemoglobin is saturated; a patient with low hemoglobin can be fully saturated yet still have reduced oxygen-carrying capacity.

70. A flow-volume loop showing a scooped-out, concave expiratory limb is most characteristic of:
    • Obstructive lung disease
    • Restrictive lung disease
    • Fixed upper airway obstruction
    • A normal study

    Correct answer: Obstructive lung disease

    Obstructive lung disease is correct because airflow limitation during exhalation produces the classic concave, scooped expiratory limb on the flow-volume loop, as seen in COPD and asthma.

71. A DLCO that is elevated above predicted values may be seen in:
    • Alveolar hemorrhage
    • Emphysema
    • Pulmonary fibrosis
    • Anemia

    Correct answer: Alveolar hemorrhage

    Alveolar hemorrhage is correct because blood within the alveoli takes up additional carbon monoxide during the test, falsely raising the measured DLCO; emphysema, fibrosis, and anemia all tend to lower it.

72. During a 6-minute walk test, the therapist should:
    • Push the patient to walk faster regardless of symptoms
    • Allow the patient to rest if needed and record distance and saturation
    • Discontinue the test at the first sign of mild fatigue
    • Withhold supplemental oxygen even if prescribed

    Correct answer: Allow the patient to rest if needed and record distance and saturation

    Allowing the patient to rest if needed and recording distance and saturation is correct because the test measures self-paced functional capacity; patients may pause, and the therapist documents total distance walked and oxygen saturation throughout.

73. A patient's peak expiratory flow has dropped to 75% of personal best. According to a standard asthma action plan, this yellow-zone reading suggests:
    • Continue routine maintenance therapy only
    • Seek emergency care immediately
    • Use quick-relief medication and monitor closely
    • No action is needed

    Correct answer: Use quick-relief medication and monitor closely

    Using quick-relief medication and monitoring closely is correct because a peak flow between 50% and 80% of personal best places the patient in the yellow zone, indicating a developing exacerbation that warrants rescue therapy.

74. A Mallampati class IV airway, in which only the hard palate is visible, should prompt the therapist to:
    • Reassure the team that intubation will be straightforward
    • Avoid all preoxygenation
    • Recommend immediate extubation
    • Anticipate a difficult intubation and prepare adjunct airway equipment

    Correct answer: Anticipate a difficult intubation and prepare adjunct airway equipment

    Anticipating a difficult intubation and preparing adjunct airway equipment is correct because a class IV view predicts limited glottic visualization; having difficult-airway tools ready improves safety during the procedure.

75. On a 12-lead ECG, ST-segment elevation in contiguous leads in a patient with chest pain most likely indicates:
    • Atrial fibrillation
    • First-degree AV block
    • Sinus bradycardia
    • Acute myocardial infarction

    Correct answer: Acute myocardial infarction

    Acute myocardial infarction is correct because ST-segment elevation across contiguous leads reflects acute injury to the myocardium, the hallmark electrocardiographic finding of an evolving heart attack.

76. A newborn at five minutes of life has a heart rate of 130, strong cry, active motion, vigorous grimace, and a completely pink body. What is the Apgar score?
    • 7
    • 8
    • 10
    • 9

    Correct answer: 10

    A score of 10 is correct because each of the five components earns the maximum 2 points: heart rate above 100, strong respiratory effort, active tone, vigorous reflex response, and fully pink color, indicating an infant in excellent condition.

77. An L/S ratio of 2.5:1 with the presence of phosphatidylglycerol in amniotic fluid indicates:
    • Fetal lung immaturity
    • An analyzer error
    • The need for emergency surfactant
    • Fetal lung maturity

    Correct answer: Fetal lung maturity

    Fetal lung maturity is correct because an L/S ratio of at least 2:1 combined with detectable phosphatidylglycerol strongly indicates mature surfactant production and a low risk of neonatal respiratory distress syndrome.

78. A spontaneous breathing trial is most appropriately conducted using which method?
    • Increasing PEEP to 15 cm H2O
    • Full assist-control ventilation
    • Neuromuscular blockade with sedation
    • A T-piece or low-level pressure support with minimal settings

    Correct answer: A T-piece or low-level pressure support with minimal settings

    A T-piece or low-level pressure support with minimal settings is correct because a spontaneous breathing trial assesses the patient's ability to breathe with little or no ventilator assistance, simulating conditions after extubation.

79. During a spontaneous breathing trial, the patient develops a respiratory rate of 38, diaphoresis, and a saturation drop to 86%. The most appropriate action is to:
    • Terminate the trial and resume ventilatory support
    • Continue the trial to build endurance
    • Recommend immediate extubation
    • Administer a neuromuscular blocker

    Correct answer: Terminate the trial and resume ventilatory support

    Terminating the trial and resuming ventilatory support is correct because tachypnea, diaphoresis, and desaturation are signs of trial failure; continuing would risk respiratory fatigue and decompensation.

80. A blood gas shows pH 7.45, PaCO2 28 mm Hg, and HCO3 19 mEq/L. This is best described as:
    • Compensated respiratory alkalosis
    • Uncompensated respiratory alkalosis
    • Uncompensated metabolic acidosis
    • Combined alkalosis

    Correct answer: Compensated respiratory alkalosis

    Compensated respiratory alkalosis is correct because the pH sits at the high end of normal while the PaCO2 is low and the HCO3 has fallen to offset it; the normalized pH indicates renal compensation for the chronic respiratory alkalosis.

81. A patient with severe diarrhea and loss of bicarbonate-rich fluid is most likely to develop:
    • Metabolic alkalosis
    • Respiratory acidosis
    • Metabolic acidosis
    • Respiratory alkalosis

    Correct answer: Metabolic acidosis

    Metabolic acidosis is correct because diarrhea causes loss of bicarbonate from the lower gastrointestinal tract, lowering the serum HCO3 and producing an acidemia of metabolic origin.

82. A patient with hypoventilation from a narcotic overdose would be expected to show which blood gas?
    • pH 7.55, PaCO2 25, HCO3 22
    • pH 7.25, PaCO2 65, HCO3 26
    • pH 7.40, PaCO2 40, HCO3 24
    • pH 7.30, PaCO2 30, HCO3 15

    Correct answer: pH 7.25, PaCO2 65, HCO3 26

    pH 7.25, PaCO2 65, HCO3 26 is correct because opioid-induced hypoventilation causes CO2 retention, producing an acute respiratory acidosis with low pH and high PaCO2 and a nearly normal bicarbonate.

83. A clinician wants to assess the efficiency of oxygen transfer across the alveolar-capillary membrane in a patient with unexplained hypoxemia and normal lungs on imaging. Which calculation is most useful?
    • Alveolar-arterial oxygen gradient
    • Minute ventilation
    • Rapid shallow breathing index
    • Vital capacity

    Correct answer: Alveolar-arterial oxygen gradient

    Alveolar-arterial oxygen gradient is correct because the A-a gradient quantifies the difference between alveolar and arterial oxygen, revealing impaired gas transfer even when other parameters appear normal.

84. A neonate with an oxygenation index of 25 despite maximal conventional ventilation should prompt the therapist to:
    • Discontinue all support
    • Consider escalation such as high-frequency ventilation or ECMO evaluation
    • Decrease the FiO2 to 0.21
    • Extubate immediately

    Correct answer: Consider escalation such as high-frequency ventilation or ECMO evaluation

    Considering escalation such as high-frequency ventilation or ECMO evaluation is correct because a rising oxygenation index reflects severe, refractory respiratory failure; an OI in this range commonly triggers advanced rescue strategies.

85. A patient assessed for weaning has a vital capacity of 12 mL/kg, a MIP of -35 cm H2O, and an RSBI of 75. These weaning parameters collectively suggest the patient:
    • Should remain on full support indefinitely
    • Requires immediate reintubation
    • Is likely ready for a spontaneous breathing trial
    • Has an oxygenation failure

    Correct answer: Is likely ready for a spontaneous breathing trial

    Is likely ready for a spontaneous breathing trial is correct because all three values meet accepted thresholds for ventilatory reserve, inspiratory strength, and breathing pattern, supporting progression toward liberation.

86. A patient with restrictive lung disease performs spirometry. Which finding is expected?
    • FEV1/FVC ratio of 0.55
    • Increased total lung capacity
    • A scooped expiratory flow-volume loop
    • Reduced FVC with a normal or increased FEV1/FVC ratio

    Correct answer: Reduced FVC with a normal or increased FEV1/FVC ratio

    Reduced FVC with a normal or increased FEV1/FVC ratio is correct because restriction limits the total volume that can be inhaled and exhaled while airflow remains relatively preserved, raising the ratio.

87. A patient with carbon monoxide exposure has a measured PaO2 of 95 mm Hg but a measured oxygen saturation by CO-oximetry of 78%. Which best explains this discrepancy?
    • A laboratory error in the PaO2
    • Carboxyhemoglobin occupying binding sites and lowering true saturation
    • Methemoglobin only, with normal carboxyhemoglobin
    • A widened A-a gradient

    Correct answer: Carboxyhemoglobin occupying binding sites and lowering true saturation

    Carboxyhemoglobin occupying binding sites and lowering true saturation is correct because carbon monoxide binds hemoglobin, reducing the fraction available for oxygen; the dissolved oxygen tension stays normal while the measured saturation falls.

88. A capnography waveform with a normal shape but a progressively rising end-tidal CO2 over several minutes most likely indicates:
    • Hyperventilation
    • Esophageal intubation
    • A circuit disconnection
    • Worsening hypoventilation or rising CO2 production

    Correct answer: Worsening hypoventilation or rising CO2 production

    Worsening hypoventilation or rising CO2 production is correct because a steadily climbing end-tidal CO2 with preserved waveform morphology reflects inadequate ventilation relative to metabolic CO2 generation.

89. A 12-lead ECG shows a regular rhythm with a consistent PR interval prolonged beyond 0.20 seconds, and every P wave is followed by a QRS. This is:
    • Second-degree AV block type II
    • First-degree AV block
    • Complete heart block
    • Atrial flutter

    Correct answer: First-degree AV block

    First-degree AV block is correct because a uniformly prolonged PR interval with every P wave conducting to a QRS defines first-degree block; higher-degree blocks involve dropped or dissociated beats.

90. A patient with neuromuscular weakness shows a declining vital capacity trend over several hours. This serial measurement is most useful for:
    • Diagnosing pneumonia
    • Detecting deteriorating ventilatory function before overt failure
    • Assessing oxygenation status
    • Measuring airway resistance

    Correct answer: Detecting deteriorating ventilatory function before overt failure

    Detecting deteriorating ventilatory function before overt failure is correct because serial vital capacity trends provide early warning that respiratory muscle strength is declining, allowing intervention before frank ventilatory failure.

91. During capnography on an intubated patient, the appearance of small oscillations in the alveolar plateau caused by the beating heart is known as:
    • Cardiogenic oscillations
    • Curare cleft
    • Rebreathing
    • A shark-fin pattern

    Correct answer: Cardiogenic oscillations

    Cardiogenic oscillations is correct because rhythmic cardiac contractions can produce small ripples on the capnogram plateau; a curare cleft instead reflects spontaneous breathing effort during paralysis.

92. A blood gas drawn from a patient with septic shock shows pH 7.28, PaCO2 30 mm Hg, and HCO3 14 mEq/L. The low PaCO2 represents:
    • The primary disorder
    • Respiratory compensation for metabolic acidosis
    • Metabolic compensation for respiratory acidosis
    • A combined acid-base disturbance

    Correct answer: Respiratory compensation for metabolic acidosis

    Respiratory compensation for metabolic acidosis is correct because the lactic acidosis of sepsis lowers bicarbonate and pH, and the patient hyperventilates to reduce PaCO2, partially offsetting the acidemia.

93. A therapist reviews a patient's MIP of -45 cm H2O. Compared with a MIP of -15 cm H2O, this more negative value indicates:
    • Weaker inspiratory muscles
    • Worse oxygenation
    • Higher airway resistance
    • Stronger inspiratory muscles

    Correct answer: Stronger inspiratory muscles

    Stronger inspiratory muscles is correct because a more negative maximum inspiratory pressure reflects greater force generation by the inspiratory muscles, which supports a favorable weaning prognosis.

94. A patient with suspected pulmonary embolism would be expected to show which capnography-related finding?
    • Elevated end-tidal CO2
    • An increased gradient between PaCO2 and end-tidal CO2
    • A normal flat capnogram
    • Rising baseline rebreathing pattern

    Correct answer: An increased gradient between PaCO2 and end-tidal CO2

    An increased gradient between PaCO2 and end-tidal CO2 is correct because an embolism creates ventilated but unperfused alveoli (dead space), reducing the exhaled CO2 relative to arterial CO2 and widening the gradient.

95. A patient on volume-controlled ventilation triggers extra breaths, and the ventilator graphics show the flow waveform not returning to baseline. Measuring auto-PEEP requires:
    • An expiratory hold maneuver
    • An inspiratory hold maneuver
    • Increasing the FiO2
    • A nebulizer treatment

    Correct answer: An expiratory hold maneuver

    An expiratory hold maneuver is correct because auto-PEEP is the trapped end-expiratory pressure; pausing at end-expiration allows alveolar and circuit pressures to equilibrate so the trapped pressure can be measured.

96. A patient breathing room air at sea level has a normal PaO2 of 95 mm Hg and a normal A-a gradient. This finding indicates that any hypoxemia present would most likely be due to:
    • Hypoventilation or low inspired oxygen rather than a gas exchange defect
    • A large intrapulmonary shunt
    • Severe V/Q mismatch
    • Diffusion impairment

    Correct answer: Hypoventilation or low inspired oxygen rather than a gas exchange defect

    Hypoventilation or low inspired oxygen rather than a gas exchange defect is correct because a normal A-a gradient rules out significant problems with oxygen transfer; remaining causes of hypoxemia involve reduced delivery of oxygen to the alveoli.

97. A patient on assist-control ventilation has a set rate of 12 and a total rate of 20 breaths/min with a tidal volume of 0.5 L. What is the total minute ventilation?
    • 6 L/min
    • 12 L/min
    • 10 L/min
    • 20 L/min

    Correct answer: 10 L/min

    10 L/min is correct because minute ventilation reflects the total delivered breaths: 20 breaths/min multiplied by 0.5 L equals 10 L/min, accounting for both mandatory and patient-triggered breaths.

98. A pulse oximetry reading should be interpreted with caution in the presence of:
    • Normal perfusion
    • Strong, regular pulsatile signal
    • A warm extremity
    • Carbon monoxide poisoning or significant methemoglobinemia

    Correct answer: Carbon monoxide poisoning or significant methemoglobinemia

    Carbon monoxide poisoning or significant methemoglobinemia is correct because these abnormal hemoglobin species cause standard pulse oximeters to give falsely reassuring or unreliable readings; CO-oximetry is required for accuracy.

99. A patient with chronic interstitial lung disease has serial DLCO measurements that are progressively declining. This trend indicates:
    • Improving gas transfer
    • Worsening alveolar-capillary diffusion
    • Increasing airway obstruction
    • Resolving disease

    Correct answer: Worsening alveolar-capillary diffusion

    Worsening alveolar-capillary diffusion is correct because a falling DLCO over time reflects progressive impairment of gas transfer across the membrane, consistent with advancing interstitial disease.

100. A patient with a peak expiratory flow of 95% of personal best and no symptoms falls into which asthma action plan zone?
     • Yellow zone
     • Red zone
     • Green zone
     • Orange zone

     Correct answer: Green zone

     The green zone is correct because a peak flow of 80% or more of personal best with no symptoms indicates good control, where the patient continues routine maintenance therapy.

101. An infant at one minute has a heart rate of 50, no spontaneous respirations, limp tone, no reflex response, and a blue body. What is the Apgar score, and what does it indicate?
     • 4, indicating mild distress
     • 6, indicating moderate distress
     • 1, indicating the need for vigorous resuscitation
     • 8, indicating good condition

     Correct answer: 1, indicating the need for vigorous resuscitation

     A score of 1 indicating the need for vigorous resuscitation is correct because only heart rate below 100 earns 1 point while all other categories score 0; this severely depressed infant requires immediate resuscitative measures.

102. A blood gas shows pH 7.62, PaCO2 48 mm Hg, and HCO3 46 mEq/L in a patient with prolonged diuretic use. This is best described as:
     • Respiratory alkalosis
     • Uncompensated metabolic alkalosis
     • Metabolic acidosis
     • Combined acidosis

     Correct answer: Uncompensated metabolic alkalosis

     Uncompensated metabolic alkalosis is correct because the markedly elevated pH and high bicarbonate indicate a metabolic alkalosis; the slightly elevated PaCO2 shows minimal respiratory compensation has occurred.

103. A spontaneous breathing trial is most useful for determining whether a patient can:
     • Increase their FiO2 tolerance
     • Improve their diffusing capacity
     • Reduce airway resistance
     • Tolerate removal of ventilatory support

     Correct answer: Tolerate removal of ventilatory support

     Tolerate removal of ventilatory support is correct because the spontaneous breathing trial directly evaluates whether a patient can maintain adequate ventilation and oxygenation with minimal or no assistance before extubation.

104. A patient's flow-volume loop shows flattening of both the inspiratory and expiratory limbs. This fixed pattern most strongly suggests:
     • Emphysema
     • A fixed upper airway obstruction
     • Restrictive disease
     • Normal lungs

     Correct answer: A fixed upper airway obstruction

     A fixed upper airway obstruction is correct because flattening of both limbs of the flow-volume loop indicates a lesion that limits flow in both directions, such as tracheal stenosis or a fixed mass.

105. A blood gas with pH 7.40, PaCO2 60 mm Hg, and HCO3 36 mEq/L in a stable patient indicates:
     • A fully compensated chronic respiratory acidosis
     • An acute life-threatening disturbance
     • Acute metabolic alkalosis
     • Respiratory alkalosis

     Correct answer: A fully compensated chronic respiratory acidosis

     A fully compensated chronic respiratory acidosis is correct because the normal pH with simultaneously elevated PaCO2 and HCO3 shows the kidneys have completely offset the chronic CO2 retention, a pattern typical of stable chronic lung disease.

106. A therapist measuring maximum inspiratory pressure in a poorly cooperative, sedated patient should:
     • Accept the first reading regardless of effort
     • Avoid the measurement entirely in all patients
     • Measure during a normal tidal breath only
     • Use a one-way valve and occlusion for up to about 20 seconds to capture the best effort

     Correct answer: Use a one-way valve and occlusion for up to about 20 seconds to capture the best effort

     Using a one-way valve and occlusion for up to about 20 seconds to capture the best effort is correct because a unidirectional valve allows exhalation but blocks inhalation, progressively building inspiratory effort to obtain a reliable MIP even with limited cooperation.

107. A patient breathing 60% oxygen has a PaO2 of 90 mm Hg. The resulting P/F ratio of 150 places the patient in which category?
     • Normal oxygenation
     • Mild ARDS
     • Severe ARDS
     • Moderate ARDS

     Correct answer: Moderate ARDS

     Moderate ARDS is correct because a P/F ratio between 100 and 200 defines the moderate category; the PaO2 of 90 divided by an FiO2 of 0.60 equals 150, falling within this range.

108. A blood gas shows pH 7.33, PaCO2 32 mm Hg, and HCO3 17 mEq/L. The respiratory system's role in this picture is to:
     • Cause the primary acidemia
     • Cause a primary alkalosis
     • Partially compensate by lowering PaCO2
     • Have no effect on the pH

     Correct answer: Partially compensate by lowering PaCO2

     Partially compensating by lowering PaCO2 is correct because the primary metabolic acidosis (low pH, low HCO3) triggers hyperventilation, which reduces the PaCO2 to partially counteract the acidemia.

109. A 12-lead ECG demonstrates regularly irregular dropped beats with progressively lengthening PR intervals until a QRS is dropped. This describes:
     • First-degree AV block
     • Complete heart block
     • Atrial fibrillation
     • Second-degree AV block, Mobitz type I (Wenckebach)

     Correct answer: Second-degree AV block, Mobitz type I (Wenckebach)

     Second-degree AV block, Mobitz type I (Wenckebach) is correct because the progressive PR prolongation culminating in a dropped beat is the defining pattern of Wenckebach conduction.

110. A patient with severe air trapping and significant auto-PEEP may experience which adverse hemodynamic effect?
     • Increased venous return and high blood pressure
     • Bradycardia with hypertension
     • Reduced venous return and hypotension
     • No hemodynamic change

     Correct answer: Reduced venous return and hypotension

     Reduced venous return and hypotension is correct because high intrathoracic pressure from auto-PEEP impedes blood return to the heart, lowering preload and cardiac output, which can cause hypotension.

111. An oxygenation index combines mean airway pressure, FiO2, and PaO2 to provide a measure that:
     • Estimates dead space volume
     • Reflects both ventilatory support intensity and the resulting oxygenation
     • Measures airway resistance
     • Calculates minute ventilation

     Correct answer: Reflects both ventilatory support intensity and the resulting oxygenation

     Reflecting both ventilatory support intensity and the resulting oxygenation is correct because the oxygenation index accounts for how much pressure and oxygen are required to achieve a given PaO2, capturing the severity of respiratory failure.

112. A patient on a 40% air-entrainment mask has the entrainment ports partially covered by a bedsheet. What is the most likely effect on the delivered oxygen concentration?
     • The FiO2 will fall below the set value
     • The FiO2 will rise above the set value
     • The FiO2 will stay exactly at 40%
     • The total flow will increase

     Correct answer: The FiO2 will rise above the set value

     The delivered FiO2 will rise above the set value is correct because obstructing the entrainment ports reduces the amount of room air mixed with the source oxygen; with less air diluting the oxygen, the concentration delivered to the patient increases.

113. An air-entrainment mask delivering a low FiO2 such as 24% entrains a large volume of room air. Compared with a 50% setting, the 24% setting produces:
     • No change in total flow
     • A lower total flow output to the patient
     • A flow equal to the source oxygen flow only
     • A higher total flow output to the patient

     Correct answer: A higher total flow output to the patient

     A higher total flow output to the patient is correct because lower FiO2 settings use a larger air-to-oxygen entrainment ratio, so much more room air is drawn in; this greatly increases the combined total flow leaving the mask.

114. A therapist notes that a patient breathing rapidly and deeply through a nasal cannula at 4 L/min has a lower-than-expected oxygen saturation. The most likely reason the actual FiO2 is lower than the estimate is that:
     • A high inspiratory demand dilutes the oxygen with more room air
     • The cannula prongs are too large
     • The humidifier is adding water vapor
     • The oxygen flowmeter is set too high

     Correct answer: A high inspiratory demand dilutes the oxygen with more room air

     A high inspiratory demand diluting the oxygen with more room air is correct because the nasal cannula is a low-flow device; when a patient breathes faster and deeper, more room air is entrained around the fixed oxygen flow, lowering the actual FiO2 delivered.

115. A nasal cannula is classified as a low-flow oxygen device primarily because:
     • It cannot deliver more than 1 L/min
     • It delivers an exact, fixed FiO2
     • It only works during exhalation
     • Its flow does not meet the patient's total inspiratory demand, so room air is entrained

     Correct answer: Its flow does not meet the patient's total inspiratory demand, so room air is entrained

     Its flow not meeting the patient's total inspiratory demand, so room air is entrained, is correct because a low-flow device supplies less gas than the patient inhales; the remaining volume is made up of room air, which makes the delivered FiO2 variable.

116. During use of a nonrebreather mask, the therapist observes the reservoir bag collapsing completely during each inspiration. The most appropriate corrective action is to:
     • Increase the oxygen flow until the bag stays partially inflated
     • Switch the patient to a nasal cannula
     • Remove one of the side exhalation valves
     • Reduce the oxygen flow to conserve gas

     Correct answer: Increase the oxygen flow until the bag stays partially inflated

     Increasing the oxygen flow until the bag stays partially inflated is correct because complete bag collapse means oxygen delivery is not keeping pace with inspiration; raising the flow restores the reserve so the patient inhales oxygen rather than entrained room air.

117. The one-way valves on a true nonrebreather mask serve to:
     • Allow room air to enter freely on inspiration
     • Prevent exhaled gas from entering the bag and limit room-air entrainment
     • Direct exhaled gas back into the reservoir bag
     • Add humidity to the inspired gas

     Correct answer: Prevent exhaled gas from entering the bag and limit room-air entrainment

     Preventing exhaled gas from entering the bag and limiting room-air entrainment is correct because the valve between the bag and mask blocks exhaled gas from diluting the reservoir, while the side valves close on inspiration to keep room air out, maximizing the delivered FiO2.

118. A high-flow nasal cannula maintains a relatively stable FiO2 even in a tachypneic patient primarily because it:
     • Uses one-way valves to block room air
     • Seals tightly against the nares like a mask
     • Delivers a total gas flow that meets or exceeds the patient's inspiratory demand
     • Operates only during inspiration

     Correct answer: Delivers a total gas flow that meets or exceeds the patient's inspiratory demand

     Delivering a total gas flow that meets or exceeds the patient's inspiratory demand is correct because high-flow nasal cannula supplies heated, humidified gas at flows up to 60 L/min, so little room air is entrained and the set FiO2 stays consistent.

119. Heating and humidifying the gas in a high-flow nasal cannula system is essential mainly because:
     • It eliminates the need to set an FiO2
     • It lowers the oxygen flow requirement
     • It increases the delivered FiO2
     • It allows comfortable tolerance of the very high flows and protects the mucosa

     Correct answer: It allows comfortable tolerance of the very high flows and protects the mucosa

     Allowing comfortable tolerance of the very high flows and protecting the mucosa is correct because gas delivered at up to 60 L/min would be intolerable and damaging if cold and dry; active heated humidification makes the therapy tolerable and preserves mucosal function.

120. A modest amount of positive airway pressure generated by high-flow nasal cannula at high flow rates is most attributed to:
     • The one-way exhalation valves
     • A sealed reservoir bag
     • Cooling of the inspired gas
     • The high flow generating a flow-dependent distending pressure

     Correct answer: The high flow generating a flow-dependent distending pressure

     The high flow generating a flow-dependent distending pressure is correct because the rapid gas flow creates a small amount of positive pressure in the nasopharynx that increases with the flow rate, providing a mild distending effect on the airway.

121. A high-pressure alarm activates on a ventilated patient who suddenly becomes hypotensive with absent breath sounds and tracheal deviation on one side. The therapist should suspect:
     • A circuit disconnection
     • Excess humidity in the circuit
     • A tension pneumothorax
     • A cuff leak

     Correct answer: A tension pneumothorax

     A tension pneumothorax is correct because air trapped under pressure in the pleural space sharply raises airway pressure while collapsing the lung and shifting the mediastinum, producing absent breath sounds, tracheal deviation, and hemodynamic instability.

122. Which of the following is a cause of a ventilator high-pressure alarm rather than a low-pressure alarm?
     • Acute bronchospasm
     • A disconnected wye connector
     • A leak at the inline suction port
     • A deflated endotracheal tube cuff

     Correct answer: Acute bronchospasm

     Acute bronchospasm is correct because narrowing of the airways increases airway resistance and the pressure needed to deliver the breath, triggering the high-pressure alarm; the other choices are leaks or disconnections that lower pressure.

123. A ventilated patient bites down on the endotracheal tube, and the high-pressure alarm sounds. The most appropriate intervention is to:
     • Insert a bite block and address patient agitation
     • Decrease the FiO2
     • Disconnect the patient from the ventilator
     • Increase the high-pressure limit to silence the alarm

     Correct answer: Insert a bite block and address patient agitation

     Inserting a bite block and addressing patient agitation is correct because biting kinks the tube and raises airway pressure; a bite block prevents occlusion while managing agitation reduces the behavior causing the obstruction.

124. A persistent high-pressure alarm with a rising plateau pressure and stable peak-to-plateau difference most strongly points to:
     • A disconnected exhalation valve
     • Decreased lung compliance such as worsening pulmonary edema
     • A leak in the ventilator circuit
     • Increased airway resistance from secretions

     Correct answer: Decreased lung compliance such as worsening pulmonary edema

     Decreased lung compliance such as worsening pulmonary edema is correct because a rising plateau pressure reflects stiffer lungs rather than airway narrowing; a stable difference between peak and plateau indicates resistance is unchanged.

125. A ventilator low-pressure alarm sounds and the exhaled tidal volume reads near zero. The therapist should first check for:
     • A mucus plug in the airway
     • A disconnection in the patient circuit
     • Bronchospasm
     • Kinked tubing

     Correct answer: A disconnection in the patient circuit

     A disconnection in the patient circuit is correct because a low-pressure alarm with a near-zero exhaled volume most often means gas is escaping through a break in the circuit rather than reaching the patient; reconnecting restores delivered volume.

126. A continuous low-pressure alarm on a mechanically ventilated patient with an audible gurgling around the airway and a falling exhaled volume most likely indicates:
     • Acute bronchospasm
     • A leak from an underinflated endotracheal tube cuff
     • A mucus plug obstructing the tube
     • Worsening lung compliance

     Correct answer: A leak from an underinflated endotracheal tube cuff

     A leak from an underinflated endotracheal tube cuff is correct because an inadequate cuff seal allows gas to escape around the tube, producing an audible leak, a drop in returned volume, and a low-pressure alarm.

127. Which scenario would most likely trigger a ventilator low-pressure alarm?
     • A kinked endotracheal tube
     • A patient coughing against the ventilator
     • A loose connection at the humidifier chamber
     • Acute pulmonary edema

     Correct answer: A loose connection at the humidifier chamber

     A loose connection at the humidifier chamber is correct because a loose fitting allows gas to leak from the circuit, lowering the pressure the ventilator measures; the other scenarios all raise airway pressure and would trigger a high-pressure alarm.

128. When calibrating an oxygen analyzer, the therapist exposes the sensor to room air and to 100% oxygen. What is the purpose of using these two gases?
     • To warm the sensor before use
     • To remove moisture from the sensor
     • To measure the flow of the gas source
     • To establish two-point calibration at known oxygen concentrations

     Correct answer: To establish two-point calibration at known oxygen concentrations

     Establishing two-point calibration at known oxygen concentrations is correct because room air provides a 21% reference and the source gas provides a 100% reference; calibrating to both known points ensures accurate readings across the range.

129. A galvanic oxygen analyzer reads 18% when exposed to room air during calibration and cannot be adjusted to read 21%. The most likely problem is:
     • The room air contains too much oxygen
     • The analyzer is reading the 100% point correctly
     • The flowmeter is set too high
     • A depleted sensor fuel cell that needs replacement

     Correct answer: A depleted sensor fuel cell that needs replacement

     A depleted sensor fuel cell that needs replacement is correct because a galvanic analyzer that cannot be calibrated to a known 21% reference has likely exhausted its electrochemical sensor; replacing the cell restores accurate measurement.

130. An oxygen analyzer used to verify the FiO2 delivered to a ventilated patient should be calibrated:
     • Only when the device first arrives from the manufacturer
     • Only after the analyzer has failed
     • Before use and according to facility quality-control policy
     • Once per patient admission regardless of duration

     Correct answer: Before use and according to facility quality-control policy

     Calibrating before use and according to facility quality-control policy is correct because routine calibration ensures the analyzer reports accurate oxygen concentrations; relying on factory settings or waiting for failure risks delivering an unverified FiO2.

131. On a blood gas analyzer quality-control program, a Levey-Jennings chart is used primarily to:
     • Calculate the patient's acid-base status
     • Measure the patient's oxygen saturation
     • Determine the analyzer's electrical power usage
     • Plot control results over time to detect trends and shifts

     Correct answer: Plot control results over time to detect trends and shifts

     Plotting control results over time to detect trends and shifts is correct because a Levey-Jennings chart graphs each control measurement against the established mean and standard deviation lines, allowing the technologist to spot developing analyzer problems.

132. On a Levey-Jennings chart, six consecutive control points fall on the same side of the mean without exceeding any control limit. This pattern most likely represents:
     • A power outage
     • A systematic shift in analyzer performance
     • An improvement in precision
     • Random error within acceptable limits

     Correct answer: A systematic shift in analyzer performance

     A systematic shift in analyzer performance is correct because a run of consecutive points clustered on one side of the mean indicates a consistent bias rather than random scatter, signaling the analyzer needs investigation even though no single point is out of range.

133. A Levey-Jennings chart shows control values steadily drifting upward over ten consecutive runs. This gradual trend most commonly indicates:
     • Progressive deterioration such as an aging electrode or reagent
     • A one-time random error
     • A change in the patient population
     • Correct analyzer performance

     Correct answer: Progressive deterioration such as an aging electrode or reagent

     Progressive deterioration such as an aging electrode or reagent is correct because a steady directional drift across many runs reflects a developing systematic problem in the measuring system rather than isolated random variation.

134. The Westgard multirule system is applied to blood gas analyzer quality control in order to:
     • Calculate the dilution of a sample
     • Set the patient's ventilator alarm limits
     • Decide when to accept or reject an analytic run based on control results
     • Determine the patient's FiO2

     Correct answer: Decide when to accept or reject an analytic run based on control results

     Deciding when to accept or reject an analytic run based on control results is correct because Westgard rules define specific statistical criteria that distinguish acceptable random variation from true error, guiding whether reported patient results are valid.

135. A single quality-control result falls more than three standard deviations from the mean. According to Westgard rules, the analytic run should be:
     • Reported with a comment but still released
     • Rejected because this violates a control rule
     • Repeated only if the next two points also fail
     • Accepted because one point is unimportant

     Correct answer: Rejected because this violates a control rule

     Rejected because this violates a control rule is correct because a result beyond three standard deviations breaches the 1-3s Westgard rule, indicating unacceptable error; the run should be rejected and patient results withheld until resolved.

136. Westgard rules are designed to distinguish between which two general categories of analytic error?
     • Preanalytic and postanalytic error
     • Patient error and clerical error
     • Random error and systematic error
     • Mechanical error and electrical error

     Correct answer: Random error and systematic error

     Random error and systematic error is correct because the Westgard multirule approach uses different control rules to flag random scatter versus consistent bias, helping the laboratory identify the type of problem affecting the analyzer.

137. Under the Spaulding classification, an item that contacts intact mucous membranes but does not penetrate sterile tissue, such as a bronchoscope, is categorized as:
     • Semicritical
     • Critical
     • Environmental
     • Noncritical

     Correct answer: Semicritical

     Semicritical is correct because the Spaulding system classifies items touching mucous membranes or nonintact skin as semicritical, which require at least high-level disinfection between uses.

138. According to the Spaulding classification, which level of processing is required for a critical item that enters sterile tissue or the vascular system?
     • Low-level disinfection
     • Intermediate-level disinfection
     • Sterilization
     • High-level disinfection

     Correct answer: Sterilization

     Sterilization is correct because critical items penetrate sterile body sites and therefore carry a high infection risk; the Spaulding classification mandates sterilization to eliminate all microbial life, including spores.

139. A reusable laryngoscope blade that contacts the oral mucosa during intubation falls into which Spaulding category and minimum reprocessing level?
     • Environmental requiring cleaning only
     • Critical requiring sterilization only
     • Noncritical requiring low-level disinfection
     • Semicritical requiring high-level disinfection

     Correct answer: Semicritical requiring high-level disinfection

     Semicritical requiring high-level disinfection is correct because the blade touches mucous membranes without entering sterile tissue; the Spaulding system places such devices in the semicritical category, which calls for at least high-level disinfection.

140. A patient with suspected active pulmonary tuberculosis requires which type of isolation precautions?
     • Standard precautions only
     • Contact precautions
     • Airborne precautions
     • Droplet precautions

     Correct answer: Airborne precautions

     Airborne precautions is correct because tuberculosis is transmitted by small droplet nuclei that remain suspended in the air; airborne precautions require a fit-tested respirator and a negative-pressure airborne infection isolation room.

141. When caring for a patient on airborne precautions for measles, the therapist must place the patient in:
     • A negative-pressure airborne infection isolation room
     • A positive-pressure room
     • A standard private room with the door open
     • A shared room with another infected patient

     Correct answer: A negative-pressure airborne infection isolation room

     A negative-pressure airborne infection isolation room is correct because measles spreads via airborne particles; a negative-pressure room with the door closed and appropriate air exchanges prevents infectious aerosols from escaping into adjacent areas.

142. A patient with influenza requires droplet precautions. The minimum personal protective equipment the therapist should don when within close range is:
     • A surgical mask and eye protection
     • No protective equipment is needed
     • A fit-tested N95 respirator
     • A gown and gloves only

     Correct answer: A surgical mask and eye protection

     A surgical mask and eye protection is correct because droplet precautions guard against large respiratory droplets that travel only short distances; a surgical mask with eye protection provides adequate protection without the need for an N95 respirator.

143. Which infectious condition is managed with droplet precautions rather than airborne precautions?
     • Measles
     • Pertussis (whooping cough)
     • Varicella (chickenpox)
     • Pulmonary tuberculosis

     Correct answer: Pertussis (whooping cough)

     Pertussis (whooping cough) is correct because it is transmitted by large respiratory droplets that fall quickly and travel only a short distance; tuberculosis, varicella, and measles all spread by airborne nuclei requiring airborne precautions.

144. A patient colonized with methicillin-resistant Staphylococcus aureus (MRSA) is placed on contact precautions. Before entering the room, the therapist should don:
     • A surgical mask only
     • Eye protection only
     • A gown and gloves
     • An N95 respirator

     Correct answer: A gown and gloves

     A gown and gloves is correct because contact precautions prevent transmission of organisms spread by direct or indirect contact such as MRSA; wearing a gown and gloves blocks contamination of the therapist's hands and clothing.

145. A patient with Clostridioides difficile infection is on contact precautions. Which hand-hygiene practice is most appropriate after removing gloves?
     • Alcohol-based hand rub alone is sufficient
     • Applying additional alcohol gel without washing
     • No hand hygiene is needed after glove removal
     • Washing hands with soap and water

     Correct answer: Washing hands with soap and water

     Washing hands with soap and water is correct because C. difficile spores are not reliably killed by alcohol-based products; mechanical washing with soap and water physically removes the spores from the hands.

146. An N95 filtering facepiece respirator differs from a standard surgical mask primarily because it:
     • Requires no fit testing
     • Forms a tight seal and filters at least 95% of small airborne particles
     • Is more comfortable for long-term wear
     • Filters only large droplets

     Correct answer: Forms a tight seal and filters at least 95% of small airborne particles

     Forming a tight seal and filtering at least 95% of small airborne particles is correct because the N95 is designed to seal against the face and capture fine aerosols, providing the respiratory protection needed for airborne precautions that a loose surgical mask cannot.

147. Before relying on an N95 respirator for airborne isolation, the therapist must:
     • Perform a user seal check each time it is donned
     • Attach a reservoir bag
     • Verify it is the same size as a surgical mask
     • Soak the respirator in disinfectant

     Correct answer: Perform a user seal check each time it is donned

     Performing a user seal check each time it is donned is correct because the protection of an N95 depends on an airtight seal; a seal check confirms there are no leaks before the therapist enters an airborne isolation environment.

148. Ethylene oxide sterilization is especially useful for which type of respiratory equipment?
     • Disposable single-use suction catheters
     • Items that need only surface cleaning
     • Heat- and moisture-sensitive items that cannot tolerate steam autoclaving
     • Stainless steel surgical instruments only

     Correct answer: Heat- and moisture-sensitive items that cannot tolerate steam autoclaving

     Heat- and moisture-sensitive items that cannot tolerate steam autoclaving is correct because ethylene oxide is a low-temperature gas sterilant ideal for delicate plastics and electronics that would be damaged by the heat and moisture of an autoclave.

149. A major operational disadvantage of ethylene oxide sterilization is that it:
     • Requires a lengthy aeration period to remove toxic residual gas
     • Provides only low-level disinfection
     • Damages all plastic equipment
     • Cannot penetrate packaging

     Correct answer: Requires a lengthy aeration period to remove toxic residual gas

     Requiring a lengthy aeration period to remove toxic residual gas is correct because ethylene oxide is toxic and must be off-gassed from items through prolonged aeration before they are safe for patient use, which lengthens turnaround time.

150. A reusable bronchoscope is processed using glutaraldehyde. This agent is most appropriately classified as a:
     • High-level disinfectant for semicritical equipment
     • Low-level disinfectant
     • Surface cleaner only
     • Sterilant for critical implants

     Correct answer: High-level disinfectant for semicritical equipment

     A high-level disinfectant for semicritical equipment is correct because glutaraldehyde achieves high-level disinfection suitable for semicritical devices such as flexible endoscopes that contact mucous membranes but do not enter sterile tissue.

151. When using glutaraldehyde to disinfect respiratory equipment, the therapist must ensure that the processed items are:
     • Used immediately while still wet with the solution
     • Stored in the solution between every patient
     • Heated to activate the disinfectant
     • Thoroughly rinsed before patient use to remove residual chemical

     Correct answer: Thoroughly rinsed before patient use to remove residual chemical

     Thoroughly rinsing before patient use to remove residual chemical is correct because glutaraldehyde is irritating to mucous membranes and tissue; rinsing with sterile or filtered water removes residue that could cause chemical injury to the patient.

152. A full E-cylinder gauge reads 2,200 psi. The therapist needs the tank to last at least 60 minutes for a transport. Using a cylinder factor of 0.28, what is the maximum flow that can be set?
     • About 5 L/min
     • About 2 L/min
     • About 10 L/min
     • About 15 L/min

     Correct answer: About 10 L/min

     About 10 L/min is correct because flow equals (pressure × cylinder factor) ÷ time: (2,200 × 0.28) ÷ 60 ≈ 10 L/min as the maximum sustainable flow for the tank to last 60 minutes.

153. An oxygen E-cylinder gauge reads 1,000 psi while running at 4 L/min. Using the cylinder factor of 0.28, the therapist should plan to change the tank in approximately:
     • About 70 minutes
     • About 140 minutes
     • About 14 minutes
     • About 35 minutes

     Correct answer: About 70 minutes

     About 70 minutes is correct because (1,000 × 0.28) ÷ 4 ≈ 70 minutes — 1,000 psi times the E-cylinder factor of 0.28, divided by the flow of 4 L/min — before the cylinder is exhausted.

154. A patient on a 50% air-entrainment mask needs the device checked for adequate total flow. The therapist understands that compared with the same mask set at 24%, the 50% setting will:
     • Deliver an identical total flow at both settings
     • Entrain less room air and produce lower total flow
     • Stop entraining room air entirely
     • Entrain more room air and produce higher total flow

     Correct answer: Entrain less room air and produce lower total flow

     Entraining less room air and producing lower total flow is correct because higher FiO2 settings use a smaller air-to-oxygen entrainment ratio; with less room air drawn in, the combined total flow delivered to the patient decreases, which can fall below a tachypneic patient's demand.

155. An adult man requires oral intubation. Which endotracheal tube size is generally most appropriate as an initial selection?
     • 5.0 mm internal diameter
     • 8.0 mm internal diameter
     • 6.0 mm internal diameter
     • 10.0 mm internal diameter

     Correct answer: 8.0 mm internal diameter

     An 8.0 mm internal diameter tube is correct because adult men are typically intubated with an 8.0 to 9.0 mm tube; this size balances adequate airflow and suctioning access against the risk of airway trauma.

156. A therapist measures an endotracheal tube cuff pressure of 38 cm H2O. The most appropriate action is to:
     • Leave the pressure unchanged
     • Remove air until the pressure falls into the 20 to 30 cm H2O range
     • Remove all air from the cuff
     • Add more air to reach 40 cm H2O

     Correct answer: Remove air until the pressure falls into the 20 to 30 cm H2O range

     Removing air until the pressure falls into the 20 to 30 cm H2O range is correct because pressures above 30 cm H2O can exceed tracheal capillary perfusion pressure and cause mucosal ischemia; reducing the cuff pressure protects the tracheal wall.

157. Which finding best indicates a ventilated patient is ready for extubation?
     • An intact gag and cough with the underlying cause of failure resolved
     • A rapid shallow breathing index of 130
     • A FiO2 requirement of 0.70
     • Continuous infusion of a paralytic agent

     Correct answer: An intact gag and cough with the underlying cause of failure resolved

     An intact gag and cough with the underlying cause of failure resolved is correct because successful extubation requires the patient to protect the airway and clear secretions once the original problem has improved; the other findings indicate the patient is not ready.

158. When suctioning a newly placed tracheostomy, the therapist should limit the depth of insertion to:
     • The level of the carina with vigorous probing
     • As far as the catheter will advance
     • Just beyond the tip of the tracheostomy tube
     • Halfway down the trachea regardless of tube length

     Correct answer: Just beyond the tip of the tracheostomy tube

     Just beyond the tip of the tracheostomy tube is correct because shallow suctioning that reaches only slightly past the tube tip removes secretions while minimizing mucosal trauma; deep suctioning to the carina causes injury and bleeding.

159. A laryngeal mask airway is best described as a device that:
     • Passes through the vocal cords into the trachea
     • Is inserted surgically through the cricothyroid membrane
     • Provides a definitive airway protected against aspiration
     • Seals over the laryngeal inlet without entering the trachea

     Correct answer: Seals over the laryngeal inlet without entering the trachea

     Sealing over the laryngeal inlet without entering the trachea is correct because the laryngeal mask airway is a supraglottic device that rests above the glottis; it does not pass through the cords like an endotracheal tube.

160. A patient with stable COPD has a resting room-air PaO2 of 52 mm Hg. Based on standard criteria, the therapist should recommend:
     • No supplemental oxygen
     • Long-term home oxygen therapy
     • Oxygen only during sleep
     • Oxygen only during exercise

     Correct answer: Long-term home oxygen therapy

     Long-term home oxygen therapy is correct because a resting PaO2 of 55 mm Hg or less qualifies a patient for continuous home oxygen; treating the chronic hypoxemia improves survival and reduces complications.

161. When teaching a patient to use a metered-dose inhaler with a spacer, the therapist should instruct the patient to:
     • Exhale rapidly immediately after actuation
     • Actuate the inhaler and inhale slowly and deeply, then hold the breath about 10 seconds
     • Inhale as forcefully and quickly as possible
     • Take several rapid breaths through the spacer after one actuation

     Correct answer: Actuate the inhaler and inhale slowly and deeply, then hold the breath about 10 seconds

     Actuating the inhaler and inhaling slowly and deeply, then holding the breath about 10 seconds is correct because a slow, deep inspiration followed by a breath hold allows the aerosol to deposit in the lower airways rather than impacting in the mouth.

162. A patient with an acute asthma exacerbation and audible wheezing should most appropriately receive which nebulized medication first?
     • Dornase alfa
     • Hypertonic saline
     • Racemic epinephrine
     • Albuterol

     Correct answer: Albuterol

     Albuterol is correct because this short-acting beta-2 agonist produces rapid bronchodilation, directly relieving the bronchospasm causing the wheezing in an acute asthma attack.

163. Ipratropium produces bronchodilation through which mechanism?
     • Blocking muscarinic (anticholinergic) receptors
     • Stimulating beta-2 adrenergic receptors
     • Thinning airway mucus
     • Reducing airway inflammation

     Correct answer: Blocking muscarinic (anticholinergic) receptors

     Blocking muscarinic (anticholinergic) receptors is correct because ipratropium is an anticholinergic agent that inhibits acetylcholine-mediated bronchoconstriction, opening the airways through a different pathway than beta agonists.

164. A child develops inspiratory stridor and barking cough from croup. Which nebulized medication is most appropriate to reduce the airway edema?
     • Albuterol
     • Dornase alfa
     • Racemic epinephrine
     • Hypertonic saline

     Correct answer: Racemic epinephrine

     Racemic epinephrine is correct because its alpha-adrenergic vasoconstriction reduces mucosal swelling in the upper airway, rapidly decreasing the stridor and edema characteristic of croup.

165. Dornase alfa is administered by nebulizer most appropriately to which patient?
     • A patient with acute bronchospasm
     • A patient with post-extubation stridor
     • A patient with cystic fibrosis and thick, tenacious secretions
     • A patient with central sleep apnea

     Correct answer: A patient with cystic fibrosis and thick, tenacious secretions

     A patient with cystic fibrosis and thick, tenacious secretions is correct because dornase alfa is a mucolytic that breaks down DNA in purulent sputum, reducing the viscosity of the secretions characteristic of cystic fibrosis.

166. Nebulized hypertonic saline improves airway clearance primarily by:
     • Drawing water into the airway surface to hydrate and loosen secretions
     • Relaxing bronchial smooth muscle
     • Killing airway bacteria directly
     • Reducing airway inflammation

     Correct answer: Drawing water into the airway surface to hydrate and loosen secretions

     Drawing water into the airway surface to hydrate and loosen secretions is correct because the osmotic effect of hypertonic saline pulls fluid onto the airway, rehydrating the mucus layer and making secretions easier to clear.

167. In assist-control ventilation, a patient who triggers a breath above the set rate receives:
     • A breath at the full set tidal volume or pressure
     • A breath with only the spontaneous tidal volume the patient generates
     • No additional support beyond PEEP
     • A reduced level of support compared with mandatory breaths

     Correct answer: A breath at the full set tidal volume or pressure

     A breath at the full set tidal volume or pressure is correct because in assist-control mode every triggered breath, whether patient- or time-initiated, delivers the full machine support, which reduces the work of breathing.

168. Pressure support ventilation assists a patient by:
     • Delivering a set rate of mandatory breaths
     • Providing a fixed tidal volume regardless of effort
     • Augmenting each spontaneous breath with a preset inspiratory pressure
     • Cycling on a time-triggered basis only

     Correct answer: Augmenting each spontaneous breath with a preset inspiratory pressure

     Augmenting each spontaneous breath with a preset inspiratory pressure is correct because pressure support adds a clinician-set pressure to the patient's own inspiratory efforts, reducing the work of breathing while the patient controls the rate and inspiratory time.

169. In synchronized intermittent mandatory ventilation, breaths taken by the patient between the mandatory breaths are:
     • Spontaneous, with the volume determined by the patient's effort
     • Delivered at the full set tidal volume
     • Blocked until the next mandatory breath
     • Always pressure-controlled to a fixed pressure

     Correct answer: Spontaneous, with the volume determined by the patient's effort

     Spontaneous, with the volume determined by the patient's effort is correct because in SIMV the mandatory breaths are synchronized to the patient, but any additional breaths the patient takes are unsupported spontaneous breaths whose size depends on the patient.

170. Airway pressure release ventilation (APRV) is best characterized as:
     • A mode applying a high continuous pressure with brief timed releases to a lower pressure
     • A mode with two equal time periods at low pressure
     • A volume-targeted mode with a guaranteed tidal volume
     • A mode that prohibits spontaneous breathing

     Correct answer: A mode applying a high continuous pressure with brief timed releases to a lower pressure

     A mode applying a high continuous pressure with brief timed releases to a lower pressure is correct because APRV maintains lung recruitment with a sustained high pressure (P high) interrupted by short releases (P low) that allow CO2 elimination.

171. Pressure-regulated volume control (PRVC) is best described as a mode that:
     • Targets a set tidal volume while delivering it with a decelerating pressure-limited breath and adjusting pressure breath to breath
     • Provides a fixed pressure with variable volume and no volume target
     • Allows only spontaneous breaths
     • Delivers a constant flow square waveform with no pressure limit

     Correct answer: Targets a set tidal volume while delivering it with a decelerating pressure-limited breath and adjusting pressure breath to breath

     Targeting a set tidal volume while delivering it with a decelerating pressure-limited breath and adjusting pressure breath to breath is correct because PRVC is a dual-control mode that guarantees a volume target using the lowest pressure needed, modifying pressure as compliance changes.

172. A 70-kg ideal body weight patient with ARDS is being initiated on lung-protective ventilation. Which initial tidal volume is most appropriate?
     • About 700 mL
     • About 420 mL
     • About 980 mL
     • About 1,200 mL

     Correct answer: About 420 mL

     About 420 mL is correct because lung-protective ventilation targets roughly 6 mL/kg of ideal body weight (70 kg × 6 = 420 mL); larger volumes risk overdistension and ventilator-induced lung injury in ARDS.

173. A patient with diffuse atelectasis and refractory hypoxemia on the ventilator would most benefit from which adjustment to improve oxygenation?
     • Increasing the PEEP
     • Decreasing the PEEP
     • Decreasing the inspiratory time
     • Increasing the expiratory time

     Correct answer: Increasing the PEEP

     Increasing the PEEP is correct because positive end-expiratory pressure recruits collapsed alveoli and keeps them open at end-exhalation, increasing the surface area available for gas exchange and improving oxygenation.

174. The ARDSnet ventilation protocol is built around which core strategy?
     • High tidal volumes to maximize oxygenation
     • Avoiding all PEEP
     • Low tidal volume around 6 mL/kg with plateau pressure limited below 30 cm H2O
     • Targeting a normal PaCO2 at any cost

     Correct answer: Low tidal volume around 6 mL/kg with plateau pressure limited below 30 cm H2O

     Low tidal volume around 6 mL/kg with plateau pressure limited below 30 cm H2O is correct because the ARDSnet protocol reduces ventilator-induced lung injury by minimizing volutrauma and barotrauma through low volumes and capped plateau pressures.

175. A patient on the ventilator develops auto-PEEP because of incomplete exhalation. To reduce the auto-PEEP, the therapist should:
     • Lengthen the expiratory time by reducing the rate or shortening inspiration
     • Increase the respiratory rate
     • Increase inspiratory time
     • Decrease the tidal volume to a fixed minimum and increase the rate

     Correct answer: Lengthen the expiratory time by reducing the rate or shortening inspiration

     Lengthening the expiratory time by reducing the rate or shortening inspiration is correct because auto-PEEP results from air trapping when exhalation is too short; giving the lungs more time to empty allows trapped gas to escape.

176. Permissive hypercapnia during ARDS ventilation refers to the deliberate acceptance of:
     • A high PaO2
     • A low pH below 7.0
     • A high tidal volume
     • An elevated PaCO2 to allow protective low tidal volumes

     Correct answer: An elevated PaCO2 to allow protective low tidal volumes

     An elevated PaCO2 to allow protective low tidal volumes is correct because permissive hypercapnia tolerates a higher carbon dioxide level so that small, lung-protective tidal volumes can be used without forcing harmful increases in ventilation.

177. An I:E ratio of 1:4 on a ventilated COPD patient is selected primarily to:
     • Increase the inspiratory time
     • Improve oxygenation through inverse-ratio ventilation
     • Provide a longer expiratory time to reduce air trapping
     • Increase the mean airway pressure

     Correct answer: Provide a longer expiratory time to reduce air trapping

     Providing a longer expiratory time to reduce air trapping is correct because patients with obstruction need extra time to exhale; a low I:E ratio such as 1:4 lengthens exhalation and helps prevent auto-PEEP.

178. A spontaneous breathing trial is most appropriately initiated when the patient:
     • Requires escalating vasopressor support
     • Has a FiO2 requirement of 0.80
     • Is receiving continuous neuromuscular blockade
     • Has an improved underlying condition, adequate oxygenation on low support, and hemodynamic stability

     Correct answer: Has an improved underlying condition, adequate oxygenation on low support, and hemodynamic stability

     Having an improved underlying condition, adequate oxygenation on low support, and hemodynamic stability is correct because these readiness criteria indicate the patient may tolerate minimal support; a spontaneous breathing trial then tests the ability to breathe independently.

179. A postoperative patient with developing atelectasis is alert and cooperative. Which lung expansion therapy is most appropriate to encourage?
     • Continuous mechanical ventilation
     • High-frequency oscillatory ventilation
     • Nebulized albuterol
     • Incentive spirometry

     Correct answer: Incentive spirometry

     Incentive spirometry is correct because it encourages sustained maximal inspiration that re-expands collapsed alveoli; it is the first-line lung expansion therapy for an alert, cooperative postoperative patient at risk of atelectasis.

180. Intermittent positive pressure breathing (IPPB) is most appropriately considered for a patient who:
     • Has an untreated pneumothorax
     • Cannot take a deep breath on their own and has clinically significant atelectasis
     • Needs only routine incentive spirometry and is fully cooperative
     • Requires continuous ventilatory support

     Correct answer: Cannot take a deep breath on their own and has clinically significant atelectasis

     Cannot take a deep breath on their own and has clinically significant atelectasis is correct because IPPB delivers a positive-pressure breath to expand the lungs in patients unable to achieve adequate inspiration; an untreated pneumothorax is a contraindication.

181. Positive expiratory pressure (PEP) therapy aids airway clearance primarily by:
     • Generating back pressure during exhalation that splints airways open and moves air behind secretions
     • Delivering a high inspiratory pressure
     • Vibrating the chest wall externally
     • Thinning secretions chemically

     Correct answer: Generating back pressure during exhalation that splints airways open and moves air behind secretions

     Generating back pressure during exhalation that splints airways open and moves air behind secretions is correct because PEP therapy has the patient exhale against resistance, keeping airways patent and allowing collateral air to mobilize secretions toward the central airways.

182. Chest physiotherapy with postural drainage uses gravity to drain secretions by:
     • Positioning the patient flat at all times
     • Applying continuous suction to the airway
     • Positioning the affected lung segment uppermost so secretions flow toward the larger airways
     • Delivering positive pressure breaths

     Correct answer: Positioning the affected lung segment uppermost so secretions flow toward the larger airways

     Positioning the affected lung segment uppermost so secretions flow toward the larger airways is correct because postural drainage relies on gravity; placing the targeted segment above the carina lets secretions drain centrally where they can be coughed out or suctioned.

183. A flutter valve provides airway clearance by generating:
     • Continuous positive pressure during inspiration
     • External chest wall compression
     • A high inspiratory flow
     • Oscillating positive expiratory pressure as a steel ball intermittently interrupts exhaled flow

     Correct answer: Oscillating positive expiratory pressure as a steel ball intermittently interrupts exhaled flow

     Oscillating positive expiratory pressure as a steel ball intermittently interrupts exhaled flow is correct because the flutter valve combines PEP with vibrations created by a moving ball, loosening secretions while keeping airways open during exhalation.

184. The Acapella airway clearance device produces oscillatory positive expiratory pressure using:
     • A gravity-seated steel ball
     • External chest compression
     • Continuous high-flow gas
     • A counterweighted plug and magnet, making it effective in any position

     Correct answer: A counterweighted plug and magnet, making it effective in any position

     A counterweighted plug and magnet, making it effective in any position is correct because the Acapella generates oscillations through a magnetic mechanism rather than gravity, so it works regardless of patient position, including in bed.

185. High-frequency chest wall oscillation using an inflatable vest clears secretions by:
     • Delivering deep positive-pressure breaths
     • Rapidly compressing the chest wall to create brief expiratory airflow bursts that loosen mucus
     • Drawing water into the airway osmotically
     • Stimulating the cough reflex chemically

     Correct answer: Rapidly compressing the chest wall to create brief expiratory airflow bursts that loosen mucus

     Rapidly compressing the chest wall to create brief expiratory airflow bursts that loosen mucus is correct because the vest inflates and deflates many times per second, generating small bursts of expiratory flow that shear secretions free from the airway walls.

186. Inhaled nitric oxide is administered to a patient with severe ARDS and pulmonary hypertension primarily to:
     • Provide bronchodilation
     • Reduce airway secretions
     • Selectively dilate pulmonary vessels in ventilated lung regions to improve oxygenation
     • Increase systemic blood pressure

     Correct answer: Selectively dilate pulmonary vessels in ventilated lung regions to improve oxygenation

     Selectively dilating pulmonary vessels in ventilated lung regions to improve oxygenation is correct because inhaled nitric oxide reaches well-ventilated alveoli and dilates their vessels, redirecting blood flow to improve ventilation-perfusion matching and oxygenation.

187. Exogenous surfactant is most appropriately administered to which patient?
     • A premature neonate with respiratory distress syndrome from surfactant deficiency
     • A term newborn with meconium aspiration alone
     • An adult with COPD
     • A child with croup

     Correct answer: A premature neonate with respiratory distress syndrome from surfactant deficiency

     A premature neonate with respiratory distress syndrome from surfactant deficiency is correct because premature infants lack adequate surfactant, causing alveolar collapse; replacement surfactant restores surface tension and improves lung compliance and oxygenation.

188. According to the Neonatal Resuscitation Program, the first action for a newly born infant who is not breathing or is gasping with a heart rate below 100 after initial steps is to:
     • Begin chest compressions
     • Administer epinephrine
     • Insert an umbilical line
     • Provide positive-pressure ventilation

     Correct answer: Provide positive-pressure ventilation

     Providing positive-pressure ventilation is correct because effective ventilation is the cornerstone of neonatal resuscitation; an apneic or gasping infant with a heart rate below 100 needs positive-pressure ventilation before compressions or medications.

189. High-frequency oscillatory ventilation (HFOV) provides gas exchange using:
     • Large tidal volumes at a slow rate
     • Intermittent positive pressure breaths with long expiratory pauses
     • Very small tidal volumes delivered at very high frequencies around a constant mean airway pressure
     • A single large recruitment breath per minute

     Correct answer: Very small tidal volumes delivered at very high frequencies around a constant mean airway pressure

     Very small tidal volumes delivered at very high frequencies around a constant mean airway pressure is correct because HFOV maintains a steady mean airway pressure for oxygenation while tiny oscillating volumes at high frequency accomplish ventilation, minimizing volutrauma.

190. A ventilated patient has a PaCO2 of 55 mm Hg and the clinician wants to lower it. The most direct ventilator adjustment is to:
     • Decrease the minute ventilation
     • Increase the minute ventilation by raising the rate or tidal volume
     • Increase the PEEP
     • Increase the FiO2

     Correct answer: Increase the minute ventilation by raising the rate or tidal volume

     Increasing the minute ventilation by raising the rate or tidal volume is correct because PaCO2 is inversely related to alveolar ventilation; increasing minute ventilation removes more carbon dioxide and lowers the PaCO2.

191. A therapist preparing to orally intubate an average-sized adult woman should select which endotracheal tube size?
     • 4.5 mm internal diameter
     • 7.0 mm internal diameter
     • 9.5 mm internal diameter
     • 5.5 mm internal diameter

     Correct answer: 7.0 mm internal diameter

     A 7.0 mm internal diameter tube is correct because adult women are usually intubated with a 7.0 to 8.0 mm tube; selecting a tube too small increases airway resistance and limits suctioning, while too large risks mucosal injury.

192. An endotracheal tube cuff pressure of 12 cm H2O is measured in a ventilated patient who has an audible air leak. The therapist should:
     • Deflate the cuff completely
     • Add air until the pressure reaches the 20 to 30 cm H2O range
     • Replace the tube immediately
     • Leave the cuff as is

     Correct answer: Add air until the pressure reaches the 20 to 30 cm H2O range

     Adding air until the pressure reaches the 20 to 30 cm H2O range is correct because a cuff pressure below 20 cm H2O often fails to seal the airway, allowing leaks and increasing aspiration risk; restoring the proper range maintains the seal.

193. Before extubation, a therapist performs a cuff-leak test and finds no leak when the cuff is deflated. This result most strongly suggests:
     • Laryngeal edema that may cause post-extubation stridor
     • The patient is ready for immediate extubation
     • A faulty endotracheal tube cuff
     • Adequate cough strength

     Correct answer: Laryngeal edema that may cause post-extubation stridor

     Laryngeal edema that may cause post-extubation stridor is correct because the absence of an audible leak around a deflated cuff suggests the airway around the tube is swollen; extubation in this setting carries a higher risk of upper airway obstruction.

194. A patient with a new tracheostomy suddenly becomes dyspneic, and the therapist cannot pass a suction catheter through the tube. The most appropriate immediate action is to:
     • Increase the FiO2 and observe
     • Deflate the cuff and wait
     • Remove the inner cannula to check for obstruction
     • Reposition the patient and recheck in 15 minutes

     Correct answer: Remove the inner cannula to check for obstruction

     Removing the inner cannula to check for obstruction is correct because a mucus plug or crust in the inner cannula commonly blocks the tracheostomy; removing and cleaning or replacing the inner cannula quickly restores a patent airway.

195. A laryngeal mask airway is most appropriately selected in which situation?
     • Rescue ventilation when endotracheal intubation has failed and bag-mask is difficult
     • A patient with a full stomach at high risk of aspiration
     • Long-term mechanical ventilation over several weeks
     • A patient who needs frequent deep tracheal suctioning

     Correct answer: Rescue ventilation when endotracheal intubation has failed and bag-mask is difficult

     Rescue ventilation when endotracheal intubation has failed and bag-mask is difficult is correct because the laryngeal mask airway is a key tool in the difficult-airway algorithm, providing rapid supraglottic ventilation when other methods fail.

196. Which resting room-air finding meets the threshold for prescribing long-term home oxygen therapy?
     • SpO2 of 88%
     • SpO2 of 92%
     • PaO2 of 70 mm Hg
     • PaO2 of 65 mm Hg

     Correct answer: SpO2 of 88%

     An SpO2 of 88% is correct because the standard qualifying criterion for home oxygen is a resting SpO2 of 88% or lower (or PaO2 of 55 mm Hg or lower); the other values are above the threshold for continuous oxygen.

197. A patient using a metered-dose inhaler without a spacer fires the canister but the medication consistently lands on the back of the throat. Adding which device would most improve drug delivery to the lungs?
     • A small-volume nebulizer cup
     • A bacterial filter
     • A bubble humidifier
     • A spacer or valved holding chamber

     Correct answer: A spacer or valved holding chamber

     A spacer or valved holding chamber is correct because it holds the aerosol plume so the patient can inhale it more slowly, reducing oropharyngeal impaction and improving the fraction of drug reaching the lower airways.

198. Shortly after a patient receives a nebulized albuterol treatment, the therapist notes the heart rate has increased from 80 to 115. This change most likely represents:
     • An allergic reaction requiring the drug be stopped permanently
     • A common beta-1 cross-stimulation side effect of the beta-2 agonist
     • An anticholinergic effect of the medication
     • A sign of worsening bronchospasm

     Correct answer: A common beta-1 cross-stimulation side effect of the beta-2 agonist

     A common beta-1 cross-stimulation side effect of the beta-2 agonist is correct because albuterol can stimulate cardiac beta receptors at higher doses, producing tachycardia and tremor; the therapist should monitor the heart rate and continue assessing the response.

199. Ipratropium is frequently combined with albuterol in a single nebulized treatment for a COPD exacerbation because:
     • The two drugs cancel each other's side effects
     • Ipratropium thins secretions while albuterol thickens them
     • The anticholinergic and beta-2 agonist produce additive bronchodilation through different mechanisms
     • Combining them eliminates the need for oxygen

     Correct answer: The anticholinergic and beta-2 agonist produce additive bronchodilation through different mechanisms

     The anticholinergic and beta-2 agonist producing additive bronchodilation through different mechanisms is correct because pairing ipratropium with albuterol acts on separate receptor pathways, yielding greater airway opening than either drug alone in a COPD exacerbation.

200. After a patient receives nebulized racemic epinephrine for post-extubation stridor, the therapist should monitor for which possible occurrence?
     • Permanent loss of the cough reflex
     • Rebound airway edema after the drug wears off
     • Development of metabolic alkalosis
     • A drop in heart rate

     Correct answer: Rebound airway edema after the drug wears off

     Rebound airway edema after the drug wears off is correct because the vasoconstrictive effect of racemic epinephrine is temporary; swelling can return as the medication dissipates, so the patient must be observed for recurrent stridor.

201. Dornase alfa reduces sputum viscosity by:
     • Stimulating beta-2 receptors
     • Adding water to the airway by osmosis
     • Cleaving extracellular DNA released from degraded neutrophils
     • Constricting the bronchial mucosa

     Correct answer: Cleaving extracellular DNA released from degraded neutrophils

     Cleaving extracellular DNA released from degraded neutrophils is correct because dornase alfa is a recombinant enzyme that breaks down the DNA strands that make cystic fibrosis sputum thick and difficult to clear.

202. A patient receiving nebulized hypertonic saline begins to cough and wheeze during the treatment. The most appropriate response is to:
     • Continue without any precaution because this is expected
     • Consider pretreatment with a bronchodilator on future treatments because hypertonic saline can provoke bronchospasm
     • Switch immediately to dornase alfa
     • Increase the saline concentration

     Correct answer: Consider pretreatment with a bronchodilator on future treatments because hypertonic saline can provoke bronchospasm

     Considering pretreatment with a bronchodilator on future treatments because hypertonic saline can provoke bronchospasm is correct because the hyperosmolar aerosol can irritate the airways and trigger bronchoconstriction; a prior bronchodilator helps prevent this reaction.

203. A spontaneously breathing patient is placed on assist-control ventilation at a rate of 12 but is breathing at 30 per minute. The therapist should anticipate which potential complication?
     • Inadequate minute ventilation
     • Respiratory alkalosis from overventilation
     • Auto-triggering shutdown of the ventilator
     • Loss of all PEEP

     Correct answer: Respiratory alkalosis from overventilation

     Respiratory alkalosis from overventilation is correct because every assisted breath in assist-control delivers a full tidal volume; a high spontaneous rate therefore produces a large minute ventilation that can drive the PaCO2 down and the pH up.

204. A pressure support breath typically cycles from inspiration to expiration when:
     • A set time interval elapses
     • A preset tidal volume is reached
     • The patient reaches the backup rate
     • The inspiratory flow falls to a percentage of its peak

     Correct answer: The inspiratory flow falls to a percentage of its peak

     The inspiratory flow falling to a percentage of its peak is correct because pressure support is flow-cycled; as the patient's inspiratory flow decelerates to a threshold percentage of the peak, the ventilator ends the breath and allows exhalation.

205. The 'synchronized' feature of SIMV is designed to:
     • Time mandatory breaths to coincide with the patient's inspiratory effort to avoid breath stacking
     • Prevent the patient from triggering any breath
     • Deliver mandatory breaths only during exhalation
     • Eliminate the need for a set rate

     Correct answer: Time mandatory breaths to coincide with the patient's inspiratory effort to avoid breath stacking

     Timing mandatory breaths to coincide with the patient's inspiratory effort to avoid breath stacking is correct because synchronization delivers the mandatory breath when the patient begins to inhale, preventing a machine breath from stacking on top of a spontaneous one.

206. A primary goal of using APRV in a patient with refractory hypoxemia is to:
     • Minimize mean airway pressure
     • Maximize alveolar recruitment with a prolonged high pressure while allowing spontaneous breathing
     • Prevent the patient from breathing spontaneously
     • Deliver the lowest possible PEEP

     Correct answer: Maximize alveolar recruitment with a prolonged high pressure while allowing spontaneous breathing

     Maximizing alveolar recruitment with a prolonged high pressure while allowing spontaneous breathing is correct because APRV sustains a high mean airway pressure to open collapsed alveoli and permits the patient to breathe spontaneously throughout the cycle, improving oxygenation.

207. As a PRVC patient's lung compliance improves, the ventilator responds by:
     • Decreasing the inspiratory pressure while still delivering the target volume
     • Increasing the inspiratory pressure to maintain the volume
     • Holding the pressure constant and increasing the volume
     • Switching to spontaneous mode automatically

     Correct answer: Decreasing the inspiratory pressure while still delivering the target volume

     Decreasing the inspiratory pressure while still delivering the target volume is correct because PRVC continuously measures delivered volume and lowers the applied pressure when the lungs become more compliant, providing the set volume with the least pressure.

208. Tidal volume in mechanical ventilation is calculated using ideal body weight rather than actual body weight because:
     • Lung size correlates with height and predicted body weight, not fat mass
     • Actual weight is harder to measure
     • Ideal body weight always exceeds actual weight
     • Fat tissue increases lung volume proportionally

     Correct answer: Lung size correlates with height and predicted body weight, not fat mass

     Lung size correlating with height and predicted body weight, not fat mass is correct because lung volume depends on body frame and height; using ideal body weight prevents overestimating the appropriate tidal volume in overweight patients.

209. When using an ARDSnet PEEP/FiO2 table, the PEEP and FiO2 are titrated together to:
     • Minimize the mean airway pressure
     • Maintain the lowest possible PEEP regardless of oxygenation
     • Eliminate the need to monitor plateau pressure
     • Achieve target oxygenation while limiting both oxygen toxicity and overdistension

     Correct answer: Achieve target oxygenation while limiting both oxygen toxicity and overdistension

     Achieving target oxygenation while limiting both oxygen toxicity and overdistension is correct because the table pairs incremental PEEP with FiO2 levels to reach an acceptable PaO2 or SpO2 using a balance that protects the lungs.

210. Under the ARDSnet protocol, when a low tidal volume causes the PaCO2 to rise and the pH to fall modestly, the accepted approach is generally to:
     • Immediately return to high tidal volumes
     • Add large amounts of bicarbonate to fully normalize the pH
     • Discontinue mechanical ventilation
     • Tolerate the elevated PaCO2 as permissive hypercapnia within an acceptable pH range

     Correct answer: Tolerate the elevated PaCO2 as permissive hypercapnia within an acceptable pH range

     Tolerating the elevated PaCO2 as permissive hypercapnia within an acceptable pH range is correct because the ARDSnet strategy accepts a higher CO2 to protect the lungs, intervening only if the pH falls below the protocol's lower limit.

211. To reduce an elevated plateau pressure caused by overdistension in a volume-controlled patient, the most appropriate change is to:
     • Increase the tidal volume
     • Increase the inspiratory flow rate
     • Decrease the tidal volume
     • Add an inspiratory pause

     Correct answer: Decrease the tidal volume

     Decreasing the tidal volume is correct because the plateau pressure reflects the volume distending the alveoli; reducing the delivered volume lowers the distending pressure and helps bring the plateau pressure below the protective threshold.

212. A relative contraindication to permissive hypercapnia is:
     • Mild metabolic alkalosis
     • A normal cardiac output
     • A PaO2 of 90 mm Hg
     • Increased intracranial pressure

     Correct answer: Increased intracranial pressure

     Increased intracranial pressure is correct because a rising PaCO2 causes cerebral vasodilation that further raises intracranial pressure; permissive hypercapnia should be avoided in patients with brain injury or elevated intracranial pressure.

213. Inverse-ratio ventilation uses an I:E ratio such as 2:1 mainly to:
     • Shorten the inspiratory time
     • Lengthen exhalation in obstructive disease
     • Reduce the work of breathing in a weaning patient
     • Increase mean airway pressure to improve oxygenation in severe ARDS

     Correct answer: Increase mean airway pressure to improve oxygenation in severe ARDS

     Increasing mean airway pressure to improve oxygenation in severe ARDS is correct because prolonging inspiration relative to expiration raises the average airway pressure, recruiting alveoli and improving oxygenation when conventional settings fail.

214. A rapid shallow breathing index of 130 obtained during a weaning assessment indicates that the therapist should:
     • Proceed directly to extubation
     • Increase the FiO2
     • Discontinue all monitoring
     • Continue ventilatory support because weaning failure is likely

     Correct answer: Continue ventilatory support because weaning failure is likely

     Continuing ventilatory support because weaning failure is likely is correct because an index above 105 reflects rapid, shallow breathing associated with a high probability of failing a spontaneous breathing trial, so the patient is not yet ready to be liberated.

215. During a spontaneous breathing trial, which observation most strongly indicates the trial should be stopped?
     • A respiratory rate of 22
     • Sustained tachypnea above 35 with diaphoresis and a falling saturation
     • A heart rate increase of 5 beats per minute
     • A stable blood pressure

     Correct answer: Sustained tachypnea above 35 with diaphoresis and a falling saturation

     Sustained tachypnea above 35 with diaphoresis and a falling saturation is correct because these are objective signs of intolerance; continuing the trial would risk respiratory muscle fatigue and decompensation, so support should be resumed.

216. When coaching incentive spirometry, the therapist should instruct the patient to:
     • Inhale slowly and deeply, then hold the breath briefly at maximal inspiration
     • Exhale forcefully into the device
     • Take rapid shallow breaths
     • Blow out as hard and fast as possible

     Correct answer: Inhale slowly and deeply, then hold the breath briefly at maximal inspiration

     Inhaling slowly and deeply, then holding the breath briefly at maximal inspiration is correct because a sustained maximal inspiration with a breath hold maximizes alveolar re-expansion; forced exhalation does not achieve the lung expansion the therapy intends.

217. A contraindication to intermittent positive pressure breathing is:
     • An untreated tension pneumothorax
     • Mild postoperative pain
     • A cooperative patient
     • A productive cough

     Correct answer: An untreated tension pneumothorax

     An untreated tension pneumothorax is correct because applying positive pressure would force more air into the pleural space and worsen the pneumothorax; this is an absolute contraindication to IPPB.

218. During PEP therapy, the patient is typically instructed to perform which maneuver to clear the mobilized secretions?
     • A series of huff coughs after several PEP breaths
     • A forced inspiratory hold
     • Rapid panting
     • A Valsalva maneuver against a closed glottis

     Correct answer: A series of huff coughs after several PEP breaths

     A series of huff coughs after several PEP breaths is correct because the PEP breaths move secretions toward larger airways, and huff coughing then clears them without causing the airway collapse that a forceful cough can produce.

219. A patient with increased intracranial pressure has thick secretions. The therapist should recognize that which component of chest physiotherapy is a concern?
     • The use of a mouthpiece
     • Head-down (Trendelenburg) positioning, which can further raise intracranial pressure
     • Percussion of the anterior chest
     • Encouraging the patient to cough

     Correct answer: Head-down (Trendelenburg) positioning, which can further raise intracranial pressure

     Head-down (Trendelenburg) positioning, which can further raise intracranial pressure is correct because tilting the head below the body increases cerebral venous pressure; this position is contraindicated or used cautiously in patients with elevated intracranial pressure.

220. A limitation of the flutter valve that the Acapella device overcomes is that the flutter valve:
     • Cannot generate any positive pressure
     • Is gravity-dependent and requires the patient to be upright
     • Delivers aerosolized medication
     • Cannot be cleaned

     Correct answer: Is gravity-dependent and requires the patient to be upright

     Being gravity-dependent and requiring the patient to be upright is correct because the flutter valve relies on a ball seated by gravity, so it works only in certain positions; the Acapella produces oscillation independent of position.

221. An advantage of the Acapella device over postural drainage with manual percussion is that it:
     • Allows the patient to perform airway clearance independently
     • Requires a caregiver to perform percussion
     • Eliminates the need for the patient to cough
     • Delivers a measured dose of bronchodilator

     Correct answer: Allows the patient to perform airway clearance independently

     Allowing the patient to perform airway clearance independently is correct because the Acapella is a handheld oscillatory PEP device the patient can self-administer, unlike manual chest physiotherapy that requires another person.

222. High-frequency chest wall oscillation therapy is especially useful for a patient who:
     • Needs lung expansion for atelectasis only
     • Has an acute pneumothorax
     • Requires bronchodilation only
     • Has chronic, copious secretions and benefits from independent airway clearance, such as in cystic fibrosis

     Correct answer: Has chronic, copious secretions and benefits from independent airway clearance, such as in cystic fibrosis

     Having chronic, copious secretions and benefits from independent airway clearance, such as in cystic fibrosis is correct because the vest provides consistent, hands-free secretion mobilization, making it well suited to patients with ongoing heavy secretion burdens.

223. When weaning inhaled nitric oxide, the therapist should taper it gradually because abrupt discontinuation can cause:
     • A sudden rise in systemic blood pressure
     • An immediate rise in PaCO2
     • Bronchospasm
     • Rebound pulmonary hypertension and worsening oxygenation

     Correct answer: Rebound pulmonary hypertension and worsening oxygenation

     Rebound pulmonary hypertension and worsening oxygenation is correct because stopping inhaled nitric oxide suddenly removes the pulmonary vasodilation abruptly, which can cause a rebound increase in pulmonary pressures and a fall in oxygenation.

224. Surfactant reduces the work of breathing in a neonate by:
     • Increasing airway resistance
     • Lowering alveolar surface tension to prevent collapse and improve compliance
     • Thinning airway secretions
     • Stimulating the respiratory drive

     Correct answer: Lowering alveolar surface tension to prevent collapse and improve compliance

     Lowering alveolar surface tension to prevent collapse and improve compliance is correct because surfactant decreases the surface tension within alveoli, keeping them open at end-expiration and reducing the pressure needed to inflate the lungs.

225. On high-frequency oscillatory ventilation, oxygenation is primarily adjusted by changing the:
     • Amplitude (power)
     • Mean airway pressure and FiO2
     • Frequency in hertz
     • Inspiratory time percentage only

     Correct answer: Mean airway pressure and FiO2

     Mean airway pressure and FiO2 is correct because in HFOV oxygenation depends on the constant distending mean airway pressure that recruits alveoli together with the oxygen concentration, whereas amplitude and frequency primarily affect CO2 removal.

226. A ventilated patient is overventilated with a PaCO2 of 28 mm Hg and pH 7.52. To correct this, the therapist should:
     • Increase the respiratory rate
     • Add mechanical dead space and increase the rate
     • Increase the FiO2
     • Decrease the minute ventilation by lowering the rate or tidal volume

     Correct answer: Decrease the minute ventilation by lowering the rate or tidal volume

     Decreasing the minute ventilation by lowering the rate or tidal volume is correct because the low PaCO2 and high pH reflect excessive CO2 removal; reducing minute ventilation allows the PaCO2 to rise and the pH to normalize.

227. A larger-diameter endotracheal tube is generally preferred when feasible primarily because it:
     • Reduces airway resistance and facilitates suctioning and bronchoscopy
     • Eliminates the need for cuff inflation
     • Guarantees a deeper insertion depth
     • Prevents all ventilator-associated pneumonia

     Correct answer: Reduces airway resistance and facilitates suctioning and bronchoscopy

     Reducing airway resistance and facilitating suctioning and bronchoscopy is correct because a wider lumen lowers the work of breathing through the tube and allows passage of suction catheters and a bronchoscope, which a small tube would obstruct.

228. Maintaining endotracheal tube cuff pressure within the recommended range is important chiefly to prevent:
     • Excessive tube migration
     • Tracheal mucosal ischemia while still sealing the airway
     • Loss of PEEP only
     • Accidental extubation

     Correct answer: Tracheal mucosal ischemia while still sealing the airway

     Preventing tracheal mucosal ischemia while still sealing the airway is correct because keeping the cuff between 20 and 30 cm H2O provides an adequate seal for ventilation without compressing tracheal capillaries enough to cause tissue damage.

229. A patient meets oxygenation and ventilation goals but has copious thick secretions requiring suctioning every 30 minutes. Regarding extubation, the therapist should recognize that:
     • Secretion burden is irrelevant to extubation readiness
     • Excessive secretions are a relative contraindication to extubation
     • Frequent suctioning guarantees a successful extubation
     • The patient should be extubated to reduce suctioning needs

     Correct answer: Excessive secretions are a relative contraindication to extubation

     Excessive secretions being a relative contraindication to extubation is correct because a patient who cannot manage secretions without frequent suctioning is at high risk of post-extubation airway compromise and reintubation.

230. When changing the dressing and ties on a tracheostomy, the most important safety measure is to:
     • Have a spare tracheostomy tube and obturator at the bedside in case of dislodgement
     • Cut the old ties before securing the new ones to save time
     • Remove the inner cannula permanently
     • Deflate the cuff during the entire procedure

     Correct answer: Have a spare tracheostomy tube and obturator at the bedside in case of dislodgement

     Having a spare tracheostomy tube and obturator at the bedside in case of dislodgement is correct because accidental decannulation, especially with a fresh stoma, is an emergency; ready replacement equipment allows rapid reinsertion to maintain the airway.

231. A limitation of the laryngeal mask airway compared with an endotracheal tube is that it:
     • Cannot be inserted without a laryngoscope
     • Requires surgical placement
     • Always requires neuromuscular blockade
     • Provides only partial protection against aspiration of gastric contents

     Correct answer: Provides only partial protection against aspiration of gastric contents

     Providing only partial protection against aspiration of gastric contents is correct because the laryngeal mask seals over rather than within the larynx, so it does not fully protect the airway from regurgitated material the way a cuffed endotracheal tube does.

232. A patient with cor pulmonale and a hematocrit of 58% has a resting PaO2 of 58 mm Hg. The therapist recognizes that home oxygen is indicated at this slightly higher PaO2 because:
     • Any PaO2 below 80 mm Hg qualifies
     • Evidence of end-organ effects such as polycythemia or cor pulmonale lowers the qualifying threshold to a PaO2 of 56 to 59 mm Hg
     • Hematocrit does not affect oxygen prescription
     • Cor pulmonale rules out home oxygen

     Correct answer: Evidence of end-organ effects such as polycythemia or cor pulmonale lowers the qualifying threshold to a PaO2 of 56 to 59 mm Hg

     Evidence of end-organ effects such as polycythemia or cor pulmonale lowering the qualifying threshold to a PaO2 of 56 to 59 mm Hg is correct because secondary complications of hypoxemia expand eligibility for home oxygen even when the PaO2 is just above 55 mm Hg.

233. A therapist observes a patient actuate a metered-dose inhaler twice in rapid succession during a single breath. The therapist should advise the patient to:
     • Continue, as multiple actuations per breath improve delivery
     • Wait about 30 to 60 seconds between actuations and take a separate breath for each
     • Hold the breath for 30 seconds after both puffs
     • Exhale into the inhaler before each puff

     Correct answer: Wait about 30 to 60 seconds between actuations and take a separate breath for each

     Waiting about 30 to 60 seconds between actuations and taking a separate breath for each is correct because firing two puffs in one breath wastes medication and reduces deposition; each actuation should be inhaled with its own coordinated breath.

234. The primary therapeutic effect of albuterol is to:
     • Reduce airway inflammation over days
     • Thin and break apart mucus
     • Decrease secretion volume by drying the airway
     • Relax bronchial smooth muscle to produce bronchodilation

     Correct answer: Relax bronchial smooth muscle to produce bronchodilation

     Relaxing bronchial smooth muscle to produce bronchodilation is correct because albuterol is a short-acting beta-2 agonist that stimulates receptors on airway smooth muscle, opening narrowed airways and relieving acute obstruction.

235. A patient receiving nebulized ipratropium should be cautioned that the medication may cause which side effect?
     • Dry mouth and blurred vision if it reaches the eyes
     • Bradycardia
     • Increased salivation
     • Severe diarrhea

     Correct answer: Dry mouth and blurred vision if it reaches the eyes

     Dry mouth and blurred vision if it reaches the eyes is correct because ipratropium's anticholinergic action reduces secretions and can dilate the pupils if aerosol contacts the eyes; using a mouthpiece or protecting the eyes minimizes this effect.

236. Racemic epinephrine relieves upper airway obstruction primarily by:
     • Relaxing lower airway smooth muscle
     • Thinning thick secretions
     • Causing mucosal vasoconstriction that reduces swelling
     • Blocking inflammatory mediators over several hours

     Correct answer: Causing mucosal vasoconstriction that reduces swelling

     Causing mucosal vasoconstriction that reduces swelling is correct because the alpha-adrenergic activity of racemic epinephrine constricts blood vessels in the inflamed mucosa, shrinking the edema that narrows the upper airway.

237. A therapist plans both dornase alfa and an airway clearance technique for a cystic fibrosis patient. The most effective sequencing is generally to:
     • Perform airway clearance only and skip the medication
     • Give dornase alfa only at bedtime with no clearance
     • Administer dornase alfa and then perform airway clearance to mobilize the loosened secretions
     • Perform airway clearance first, then give dornase alfa to dry the airway

     Correct answer: Administer dornase alfa and then perform airway clearance to mobilize the loosened secretions

     Administering dornase alfa and then performing airway clearance to mobilize the loosened secretions is correct because the mucolytic first thins the sputum, allowing the subsequent airway clearance technique to remove it more effectively.

238. A clinician orders nebulized hypertonic saline to obtain a sputum sample from a patient who cannot spontaneously expectorate. This use is referred to as:
     • Bronchodilation
     • Sputum induction
     • Lung recruitment
     • Mucolysis by enzymatic action

     Correct answer: Sputum induction

     Sputum induction is correct because inhaling hypertonic saline stimulates coughing and hydrates secretions, helping a patient produce a sputum specimen for analysis when none can be obtained spontaneously.

239. A key advantage of assist-control ventilation for a patient with high respiratory drive is that it:
     • Provides full ventilatory support for each breath, minimizing patient effort
     • Forces the patient to perform most of the work of breathing
     • Eliminates the need to set a backup rate
     • Prevents the patient from triggering any breaths

     Correct answer: Provides full ventilatory support for each breath, minimizing patient effort

     Providing full ventilatory support for each breath, minimizing patient effort is correct because assist-control guarantees a complete machine breath for every triggered or timed breath, off-loading the respiratory muscles of a patient in distress.

240. Pressure support is added to a patient on SIMV primarily to:
     • Increase the mandatory rate
     • Guarantee a set tidal volume on mandatory breaths
     • Overcome the resistance of the endotracheal tube during spontaneous breaths
     • Deliver PEEP during exhalation

     Correct answer: Overcome the resistance of the endotracheal tube during spontaneous breaths

     Overcoming the resistance of the endotracheal tube during spontaneous breaths is correct because a small amount of pressure support helps the patient draw an effective tidal volume through the narrow artificial airway between mandatory breaths.

241. A therapist gradually lowers the mandatory rate on SIMV from 12 to 4 while monitoring the patient. This adjustment is most commonly used to:
     • Increase the level of full support
     • Wean the patient by transferring more breathing work to the patient
     • Prevent any spontaneous breathing
     • Guarantee a constant minute ventilation

     Correct answer: Wean the patient by transferring more breathing work to the patient

     Weaning the patient by transferring more breathing work to the patient is correct because reducing the SIMV mandatory rate requires the patient to contribute more spontaneous breaths, progressively shifting the work of breathing during ventilator liberation.

242. In APRV, carbon dioxide is primarily removed during which phase?
     • The prolonged high-pressure (P high) phase
     • Spontaneous breaths only
     • The brief release to the lower pressure (P low)
     • The inspiratory pause

     Correct answer: The brief release to the lower pressure (P low)

     The brief release to the lower pressure (P low) is correct because the short timed pressure release allows the lungs to partially empty, expelling CO2; the duration of this release is adjusted to control ventilation.

243. An advantage of PRVC over conventional volume control is that it:
     • Combines a guaranteed tidal volume with the lower peak pressures of a decelerating flow pattern
     • Eliminates the need to set a respiratory rate
     • Prevents the patient from triggering breaths
     • Guarantees a fixed peak pressure regardless of volume

     Correct answer: Combines a guaranteed tidal volume with the lower peak pressures of a decelerating flow pattern

     Combining a guaranteed tidal volume with the lower peak pressures of a decelerating flow pattern is correct because PRVC secures the target volume while using a decelerating flow that tends to produce lower peak airway pressures than a fixed-flow volume mode.

244. An ARDS patient on 6 mL/kg tidal volume has a plateau pressure of 33 cm H2O. According to lung-protective strategy, the therapist should:
     • Increase the tidal volume to lower the plateau pressure
     • Reduce the tidal volume further, such as to 4 to 5 mL/kg, to keep plateau pressure below 30 cm H2O
     • Do nothing because plateau pressure is acceptable
     • Increase the respiratory rate without changing volume

     Correct answer: Reduce the tidal volume further, such as to 4 to 5 mL/kg, to keep plateau pressure below 30 cm H2O

     Reducing the tidal volume further, such as to 4 to 5 mL/kg, to keep plateau pressure below 30 cm H2O is correct because the ARDSnet approach lowers tidal volume to limit plateau pressure and prevent overdistension injury when it exceeds the 30 cm H2O target.

245. After PEEP is increased from 5 to 15 cm H2O, the blood pressure falls and the central venous pressure rises. The therapist recognizes this as:
     • An improvement in cardiac output
     • A sign of improving oxygenation only
     • A reduction in venous return and cardiac output from increased intrathoracic pressure
     • A circuit leak

     Correct answer: A reduction in venous return and cardiac output from increased intrathoracic pressure

     A reduction in venous return and cardiac output from increased intrathoracic pressure is correct because high PEEP raises the pressure in the chest, impeding blood return to the heart and lowering output; this is a recognized hemodynamic consequence of escalating PEEP.

246. Within the ARDSnet protocol, the respiratory rate may be increased up to about 35 breaths per minute primarily to:
     • Improve oxygenation directly
     • Decrease the mean airway pressure
     • Lower the FiO2 requirement
     • Help maintain minute ventilation and limit hypercapnia when tidal volume is reduced

     Correct answer: Help maintain minute ventilation and limit hypercapnia when tidal volume is reduced

     Helping maintain minute ventilation and limit hypercapnia when tidal volume is reduced is correct because lowering tidal volume reduces CO2 clearance; raising the rate compensates by increasing minute ventilation to keep the PaCO2 within an acceptable range.

247. A ventilated patient's peak pressure is 40 cm H2O and plateau pressure is 38 cm H2O. The most appropriate action to protect the lungs is to:
     • Reduce the tidal volume to lower the plateau pressure below 30 cm H2O
     • Increase the tidal volume
     • Increase the inspiratory flow
     • Add an inspiratory pause

     Correct answer: Reduce the tidal volume to lower the plateau pressure below 30 cm H2O

     Reducing the tidal volume to lower the plateau pressure below 30 cm H2O is correct because the high plateau pressure reflects excessive alveolar distending pressure; lowering tidal volume reduces the plateau pressure and the risk of barotrauma.

248. While applying permissive hypercapnia, the therapist primarily monitors which value to decide whether the strategy remains acceptable?
     • The peak inspiratory pressure
     • The arterial pH
     • The minute ventilation
     • The expired tidal volume

     Correct answer: The arterial pH

     The arterial pH is correct because permissive hypercapnia accepts a high PaCO2 only as long as the pH stays above a defined lower limit; the pH guides whether ventilation must be increased or buffering considered.

249. If the inspiratory time is set at 1 second and the respiratory rate produces a total cycle time of 4 seconds, the I:E ratio is:
     • 1:1
     • 1:2
     • 1:3
     • 1:4

     Correct answer: 1:3

     1:3 is correct because the expiratory time is the total cycle time minus the inspiratory time (4 − 1 = 3 s), giving an inspiratory-to-expiratory ratio of 1 second to 3 seconds, or 1:3.

250. A negative inspiratory force of -12 cm H2O in a patient with neuromuscular disease most appropriately prompts the therapist to:
     • Recommend immediate extubation
     • Increase the FiO2
     • Reduce the PEEP to zero
     • Continue ventilatory support because inspiratory strength is inadequate

     Correct answer: Continue ventilatory support because inspiratory strength is inadequate

     Continuing ventilatory support because inspiratory strength is inadequate is correct because a weak MIP of -12 cm H2O indicates the patient cannot generate enough inspiratory force to sustain unassisted breathing, so liberation should be delayed.

251. A spontaneous breathing trial conducted with low-level continuous positive airway pressure differs from a T-piece trial in that it:
     • Applies a small distending pressure that can offset endotracheal tube resistance
     • Provides no support at all
     • Requires the patient to be sedated
     • Guarantees a set tidal volume

     Correct answer: Applies a small distending pressure that can offset endotracheal tube resistance

     Applying a small distending pressure that can offset endotracheal tube resistance is correct because a low CPAP level helps counter the resistive load of the artificial airway, whereas a T-piece offers no positive pressure during the trial.

252. The primary therapeutic goal of incentive spirometry is to:
     • Mobilize and clear secretions
     • Deliver aerosolized bronchodilator
     • Prevent or reverse atelectasis by promoting deep inspiration
     • Measure the diffusing capacity

     Correct answer: Prevent or reverse atelectasis by promoting deep inspiration

     Preventing or reversing atelectasis by promoting deep inspiration is correct because incentive spirometry uses sustained maximal inhalation to open collapsed lung units, particularly after surgery when shallow breathing leads to atelectasis.

253. Compared with incentive spirometry, IPPB is generally reserved for situations where:
     • The patient can fully cooperate and breathe deeply
     • The patient is unable to generate an adequate spontaneous deep breath
     • Only secretion clearance is needed
     • Oxygen alone is sufficient

     Correct answer: The patient is unable to generate an adequate spontaneous deep breath

     The patient being unable to generate an adequate spontaneous deep breath is correct because IPPB substitutes positive pressure for the patient's effort; when a patient can perform incentive spirometry effectively, the simpler therapy is preferred.

254. PEP therapy is most appropriate for a patient with:
     • An acute pneumothorax
     • Retained secretions from cystic fibrosis or bronchiectasis
     • Simple postoperative atelectasis with no secretions
     • Active hemoptysis

     Correct answer: Retained secretions from cystic fibrosis or bronchiectasis

     Retained secretions from cystic fibrosis or bronchiectasis is correct because PEP therapy is an airway clearance technique designed for patients with excessive secretions; it mobilizes mucus that would otherwise be retained in conditions like these.

255. Percussion and vibration during chest physiotherapy are intended to:
     • Expand collapsed alveoli through deep inspiration
     • Deliver bronchodilator deep into the lungs
     • Measure airway resistance
     • Mechanically loosen secretions from the airway walls so they can be cleared

     Correct answer: Mechanically loosen secretions from the airway walls so they can be cleared

     Mechanically loosening secretions from the airway walls so they can be cleared is correct because percussion and vibration transmit energy to the chest that helps dislodge mucus, which postural drainage and coughing then move out of the lungs.

256. When instructing a patient on flutter valve use, the therapist should advise the patient to:
     • Inhale slowly through the device
     • Exhale actively through the device to produce the oscillations, then cough to clear secretions
     • Breathe normally without any forced effort
     • Hold the device pointing downward to stop the oscillation

     Correct answer: Exhale actively through the device to produce the oscillations, then cough to clear secretions

     Exhaling actively through the device to produce the oscillations, then coughing to clear secretions is correct because expiratory flow through the flutter valve creates the vibrations that loosen mucus, after which coughing or huffing clears the mobilized secretions.

257. When teaching Acapella use, the therapist sets the resistance dial so that the patient can:
     • Inhale forcefully against high resistance
     • Exhale for a longer time at a flow that produces comfortable oscillations
     • Hold the breath for 30 seconds
     • Exhale in a single brief blast

     Correct answer: Exhale for a longer time at a flow that produces comfortable oscillations

     Exhaling for a longer time at a flow that produces comfortable oscillations is correct because the dial is adjusted to match the patient's expiratory flow so that effective vibrations are produced over a prolonged exhalation, optimizing secretion mobilization.

258. During high-frequency chest wall oscillation therapy, the therapist should periodically pause the vest to allow the patient to:
     • Cough or huff to expel the mobilized secretions
     • Rest the chest muscles only
     • Increase the FiO2
     • Lie flat to drain the lungs

     Correct answer: Cough or huff to expel the mobilized secretions

     Coughing or huffing to expel the mobilized secretions is correct because the vest loosens mucus into the larger airways but does not remove it; pausing for the patient to cough or huff clears the secretions that have been mobilized.

259. During inhaled nitric oxide therapy, the therapist should monitor for the formation of which toxic byproduct?
     • Carboxyhemoglobin
     • Carbon monoxide
     • Methemoglobin and nitrogen dioxide
     • Sulfhemoglobin

     Correct answer: Methemoglobin and nitrogen dioxide

     Methemoglobin and nitrogen dioxide is correct because nitric oxide can oxidize hemoglobin to methemoglobin and react with oxygen to form toxic nitrogen dioxide; both must be monitored during therapy to ensure patient safety.

260. Immediately after surfactant instillation through the endotracheal tube, the therapist should anticipate the need to:
     • Permanently increase the PEEP
     • Monitor closely and reduce ventilator pressures as lung compliance rapidly improves
     • Immediately extubate the infant
     • Stop oxygen therapy

     Correct answer: Monitor closely and reduce ventilator pressures as lung compliance rapidly improves

     Monitoring closely and reduce ventilator pressures as lung compliance rapidly improves is correct because surfactant can quickly improve compliance, and failing to lower the pressures could cause overdistension or pneumothorax in the rapidly improving lungs.

261. On high-frequency oscillatory ventilation, increasing the amplitude (power) primarily results in:
     • Greater CO2 removal
     • Improved oxygenation
     • A higher mean airway pressure
     • A slower frequency

     Correct answer: Greater CO2 removal

     Greater CO2 removal is correct because the amplitude determines the size of the oscillating pressure swing and thus the small tidal volume delivered; increasing amplitude enhances ventilation and lowers the PaCO2.

262. A ventilated patient has a PaCO2 of 60 mm Hg, a rate of 12, and a tidal volume of 450 mL with a plateau pressure already at 29 cm H2O. The safest way to lower the PaCO2 is to:
     • Substantially increase the tidal volume
     • Decrease the PEEP
     • Increase the FiO2
     • Increase the respiratory rate

     Correct answer: Increase the respiratory rate

     Increasing the respiratory rate is correct because raising the rate increases minute ventilation and CO2 removal without further increasing the plateau pressure, which is already near the protective limit and would be worsened by a larger tidal volume.

263. An infant requires intubation. Which uncuffed endotracheal tube size is generally most appropriate for a full-term newborn?
     • 2.0 mm internal diameter
     • 3.0 to 3.5 mm internal diameter
     • 5.0 mm internal diameter
     • 6.0 mm internal diameter

     Correct answer: 3.0 to 3.5 mm internal diameter

     A 3.0 to 3.5 mm internal diameter tube is correct because a full-term newborn is typically intubated with an uncuffed tube of approximately 3.0 to 3.5 mm; the small airway dictates a correspondingly small tube to avoid trauma.

264. A therapist measures cuff pressure with a manometer and finds 28 cm H2O. The most appropriate action is to:
     • Add air to reach 35 cm H2O
     • Remove air to reach 10 cm H2O
     • Deflate the cuff fully
     • Leave the cuff pressure unchanged because it is within range

     Correct answer: Leave the cuff pressure unchanged because it is within range

     Leaving the cuff pressure unchanged because it is within range is correct because 28 cm H2O falls within the recommended 20 to 30 cm H2O window that seals the airway without compromising tracheal mucosal blood flow.

265. A patient passes a spontaneous breathing trial but has a Glasgow Coma Scale of 6 and cannot protect the airway. Regarding extubation, the therapist should recognize that the patient:
     • Is ready for immediate extubation
     • Needs a smaller endotracheal tube
     • Should not be extubated because airway protection is inadequate despite passing the breathing trial
     • Should be reintubated

     Correct answer: Should not be extubated because airway protection is inadequate despite passing the breathing trial

     The patient should not be extubated because airway protection is inadequate despite passing the breathing trial is correct because successful ventilation and oxygenation alone are insufficient; a patient who cannot protect the airway from aspiration is not a safe extubation candidate.

266. A patient with a fenestrated tracheostomy tube can speak when the:
     • Cuff is deflated and a speaking valve or cap directs air through the fenestration and vocal cords
     • Cuff is inflated and the fenestration is capped
     • Inner cannula is locked in place during exhalation
     • Tube is suctioned continuously

     Correct answer: Cuff is deflated and a speaking valve or cap directs air through the fenestration and vocal cords

     The cuff is deflated and a speaking valve or cap directs air through the fenestration and vocal cords is correct because deflating the cuff and using the fenestration allows exhaled air to pass upward through the larynx, enabling phonation.

267. A patient with a difficult airway is being managed when intubation and bag-mask ventilation both fail. A laryngeal mask airway is placed successfully. The therapist understands this device is best regarded as:
     • A definitive long-term airway
     • A temporizing rescue airway to maintain ventilation until a definitive airway is secured
     • A device for deep tracheal suctioning
     • A method to fully protect against aspiration

     Correct answer: A temporizing rescue airway to maintain ventilation until a definitive airway is secured

     A temporizing rescue airway to maintain ventilation until a definitive airway is secured is correct because the laryngeal mask airway provides effective supraglottic ventilation in a can't-intubate, can't-ventilate situation but is a bridge to a more definitive airway.

268. A patient requires the highest reliable oxygen concentration through a non-invasive interface while also receiving humidified high flow. The device that best meets the goal of a stable high FiO2 with comfort is:
     • A nasal cannula at 2 L/min
     • A simple mask at 5 L/min
     • An incentive spirometer
     • A high-flow nasal cannula system set to a high flow and FiO2

     Correct answer: A high-flow nasal cannula system set to a high flow and FiO2

     A high-flow nasal cannula system set to a high flow and FiO2 is correct because it delivers heated, humidified gas at flows that meet inspiratory demand, maintaining a stable high FiO2 comfortably as an initiated oxygenation intervention.

269. A nebulized treatment is ordered for a patient who is breathing too shallowly to deposit aerosol effectively. To improve drug delivery, the therapist should first instruct the patient to:
     • Breathe as rapidly as possible
     • Hold the breath continuously for one minute
     • Take slow, deep breaths with occasional breath holds during the treatment
     • Exhale forcefully throughout

     Correct answer: Take slow, deep breaths with occasional breath holds during the treatment

     Taking slow, deep breaths with occasional breath holds during the treatment is correct because a slow, deep inspiratory pattern with periodic breath holds improves aerosol penetration and deposition in the lower airways compared with rapid shallow breathing.

270. A patient receives albuterol via small-volume nebulizer. To optimize aerosol delivery, the therapist should set the gas flow driving the nebulizer to approximately:
     • 6 to 8 L/min
     • 1 to 2 L/min
     • 15 L/min
     • 25 L/min

     Correct answer: 6 to 8 L/min

     6 to 8 L/min is correct because a small-volume nebulizer is typically driven at 6 to 8 L/min to produce particles in the optimal size range for lower-airway deposition; much lower or higher flows yield less effective aerosol.

271. A patient with an acute COPD exacerbation is started on combined nebulized albuterol and ipratropium. The therapist explains that the ipratropium component is especially useful in COPD because:
     • It thins secretions enzymatically
     • It eliminates the need for oxygen
     • It reduces airway inflammation within minutes
     • Anticholinergic bronchodilation is often particularly effective in COPD-related airflow obstruction

     Correct answer: Anticholinergic bronchodilation is often particularly effective in COPD-related airflow obstruction

     Anticholinergic bronchodilation is often particularly effective in COPD-related airflow obstruction is correct because increased vagal tone contributes to COPD airflow limitation, so blocking muscarinic receptors with ipratropium provides meaningful bronchodilation in these patients.

272. After racemic epinephrine is given for post-extubation stridor, the patient should be observed for several hours specifically because:
     • The drug causes prolonged sedation
     • Stridor may recur as the vasoconstrictive effect wears off, signaling possible reintubation need
     • It causes delayed bronchospasm only
     • It raises the PaCO2 slowly

     Correct answer: Stridor may recur as the vasoconstrictive effect wears off, signaling possible reintubation need

     Stridor may recur as the vasoconstrictive effect wears off, signaling possible reintubation need is correct because the relief from racemic epinephrine is temporary; observation ensures that returning airway edema and stridor are detected so timely intervention can occur.

273. A cystic fibrosis patient is prescribed nebulized dornase alfa once daily. The therapist instructs the patient that this medication:
     • Provides immediate relief of acute wheezing
     • Should be used only during exacerbations
     • Works over time to reduce sputum viscosity and is not a rescue bronchodilator
     • Replaces the need for airway clearance

     Correct answer: Works over time to reduce sputum viscosity and is not a rescue bronchodilator

     Working over time to reduce sputum viscosity and is not a rescue bronchodilator is correct because dornase alfa is a maintenance mucolytic that thins secretions with regular use; it does not relieve acute bronchospasm and is used alongside airway clearance.

274. A patient cannot expectorate a specimen for tuberculosis testing. The therapist performs sputum induction with hypertonic saline, taking care to perform the procedure in:
     • A standard room with the door open
     • A positive-pressure room
     • Any available hallway space
     • An airborne infection isolation room because the procedure can aerosolize infectious particles

     Correct answer: An airborne infection isolation room because the procedure can aerosolize infectious particles

     An airborne infection isolation room because the procedure can aerosolize infectious particles is correct because sputum induction generates aerosols that may contain tuberculosis bacteria, so it must be done in a negative-pressure room with appropriate respiratory protection.

275. A patient on assist-control volume ventilation triggers many breaths above the set rate but each triggered breath shows a low pressure and the patient appears to be pulling hard. The most appropriate adjustment is to:
     • Decrease the trigger sensitivity to make triggering harder
     • Increase the inspiratory flow rate to better match the patient's demand
     • Decrease the tidal volume
     • Switch to a backup rate only

     Correct answer: Increase the inspiratory flow rate to better match the patient's demand

     Increasing the inspiratory flow rate to better match the patient's demand is correct because a patient with high inspiratory demand who is pulling hard against an inadequate flow experiences flow starvation; raising the flow improves synchrony and reduces work of breathing.

276. A patient on pressure support ventilation has a leak in the circuit. The therapist should anticipate that the breath may:
     • End early because the flow drops quickly
     • Deliver a guaranteed tidal volume
     • Switch automatically to assist-control
     • Fail to cycle off because the inspiratory flow never falls to the cycling threshold, prolonging inspiration

     Correct answer: Fail to cycle off because the inspiratory flow never falls to the cycling threshold, prolonging inspiration

     Failing to cycle off because the inspiratory flow never falls to the cycling threshold, prolonging inspiration is correct because a leak keeps flow elevated, so the flow-cycled pressure support breath does not reach its termination point and inspiration is prolonged.

277. A patient on SIMV with pressure support is breathing comfortably. To advance weaning while monitoring tolerance, the therapist should:
     • Increase the mandatory rate
     • Increase the tidal volume on mandatory breaths
     • Add neuromuscular blockade
     • Gradually decrease the mandatory rate and assess the patient's spontaneous breathing

     Correct answer: Gradually decrease the mandatory rate and assess the patient's spontaneous breathing

     Gradually decreasing the mandatory rate and assessing the patient's spontaneous breathing is correct because reducing the SIMV mandatory rate shifts more of the breathing work to the patient in a controlled way, allowing the therapist to evaluate readiness for liberation.

278. A patient with refractory hypoxemia is placed on APRV. The therapist adjusts the duration of the release phase (T low) primarily to:
     • Set the level of oxygenation
     • Determine the FiO2
     • Set the trigger sensitivity
     • Control carbon dioxide elimination

     Correct answer: Control carbon dioxide elimination

     Controlling carbon dioxide elimination is correct because the brief release phase in APRV allows the lungs to partially empty; lengthening or shortening this release adjusts how much CO2 is removed, while the high-pressure phase governs oxygenation.

279. A patient on PRVC suddenly has the airway pressure rising toward the high-pressure limit while the ventilator struggles to deliver the target volume. This pattern most likely indicates:
     • Improving lung compliance
     • An oversedated patient
     • A correctly functioning circuit needing no action
     • Worsening compliance or increased resistance requiring assessment

     Correct answer: Worsening compliance or increased resistance requiring assessment

     Worsening compliance or increased resistance requiring assessment is correct because PRVC raises the applied pressure to maintain the target volume when the lungs stiffen or resistance increases; pressures approaching the limit signal a developing problem to investigate.

280. A 60-kg ideal body weight ARDS patient is started at 6 mL/kg. What is the initial tidal volume?
     • About 360 mL
     • About 600 mL
     • About 480 mL
     • About 720 mL

     Correct answer: About 360 mL

     About 360 mL is correct because lung-protective ventilation uses approximately 6 mL/kg of ideal body weight; 60 kg multiplied by 6 mL/kg equals 360 mL, the appropriate starting tidal volume for ARDS.

281. A patient on the ventilator has refractory hypoxemia with a PaO2 of 55 mm Hg on an FiO2 of 1.0 and PEEP of 8 cm H2O. The most appropriate next step to improve oxygenation is to:
     • Increase the PEEP while monitoring plateau pressure and hemodynamics
     • Decrease the PEEP
     • Decrease the FiO2
     • Increase the respiratory rate

     Correct answer: Increase the PEEP while monitoring plateau pressure and hemodynamics

     Increasing the PEEP while monitoring plateau pressure and hemodynamics is correct because the FiO2 is already maximal, so further oxygenation gains come from raising PEEP to recruit alveoli, with attention to plateau pressure and blood pressure to avoid harm.

282. A ventilated ARDS patient is started on the ARDSnet protocol. The therapist sets an initial tidal volume of 6 mL/kg and a rate that may be increased up to about 35 to keep the pH acceptable. This combination reflects the protocol's emphasis on:
     • Maximizing tidal volume
     • Avoiding PEEP entirely
     • Targeting a supranormal PaO2
     • Limiting lung injury with low volumes while using rate to support ventilation

     Correct answer: Limiting lung injury with low volumes while using rate to support ventilation

     Limiting lung injury with low volumes while using rate to support ventilation is correct because the ARDSnet approach protects the lungs by capping tidal volume and plateau pressure, then adjusting the respiratory rate to maintain acceptable ventilation and pH.

283. A status asthmaticus patient on the ventilator develops hypotension and rising peak pressures. The therapist suspects auto-PEEP and should first:
     • Increase the respiratory rate
     • Increase the tidal volume
     • Briefly disconnect the patient or reduce the rate and extend expiratory time to allow trapped gas to escape
     • Increase the inspiratory time

     Correct answer: Briefly disconnect the patient or reduce the rate and extend expiratory time to allow trapped gas to escape

     Briefly disconnecting the patient or reduce the rate and extend expiratory time to allow trapped gas to escape is correct because severe air trapping can cause hemodynamic compromise; relieving the trapped gas and lengthening exhalation reverses the auto-PEEP and restores venous return.

284. A patient with severe ARDS on conventional ventilation has a plateau pressure of 32 cm H2O at 6 mL/kg. To further protect the lungs the therapist can lower the tidal volume toward 4 mL/kg, accepting that this may cause:
     • A lower PaCO2
     • A higher plateau pressure
     • Complete loss of oxygenation
     • A higher PaCO2 managed as permissive hypercapnia

     Correct answer: A higher PaCO2 managed as permissive hypercapnia

     A higher PaCO2 managed as permissive hypercapnia is correct because reducing the tidal volume further lowers CO2 clearance, so the resulting hypercapnia is tolerated within an acceptable pH range to keep the plateau pressure protective.

285. A patient on volume-controlled ventilation needs a longer expiratory time to treat air trapping but the clinician wants to keep the same tidal volume and rate. The therapist can lengthen exhalation by:
     • Decreasing the inspiratory flow rate
     • Adding an inspiratory pause
     • Increasing the inspiratory flow rate to shorten inspiration
     • Increasing the PEEP

     Correct answer: Increasing the inspiratory flow rate to shorten inspiration

     Increasing the inspiratory flow rate to shorten inspiration is correct because a faster inspiratory flow delivers the set volume more quickly, shortening inspiratory time and leaving more of the cycle for exhalation, which reduces air trapping.

286. A weaning patient's bedside parameters show a vital capacity adequate for weaning and a MIP of -28 cm H2O, but the rapid shallow breathing index is 115. The therapist should:
     • Proceed immediately to extubation
     • Continue support because the breathing pattern parameter predicts likely failure
     • Increase the FiO2
     • Recommend a tracheostomy

     Correct answer: Continue support because the breathing pattern parameter predicts likely failure

     Continuing support because the breathing pattern parameter predicts likely failure is correct because despite adequate strength, an index above 105 indicates rapid shallow breathing associated with weaning failure, so liberation should be deferred and the patient reassessed.

287. A patient is placed on a 30-minute spontaneous breathing trial. To minimize the work imposed by the endotracheal tube during the trial, the therapist may add:
     • High-level pressure support of 20 cm H2O
     • Neuromuscular blockade
     • A low level of pressure support or CPAP
     • A high PEEP of 15 cm H2O

     Correct answer: A low level of pressure support or CPAP

     A low level of pressure support or CPAP is correct because a small amount of support offsets the resistive load of the artificial airway during the trial, providing a more accurate assessment of the patient's readiness to breathe without the tube.

288. A patient on incentive spirometry consistently achieves only small inspired volumes and has persistent basilar atelectasis. The most appropriate escalation is to:
     • Discontinue lung expansion therapy
     • Switch to nebulized albuterol only
     • Consider IPPB to deliver a positive-pressure deep breath
     • Apply contact precautions

     Correct answer: Consider IPPB to deliver a positive-pressure deep breath

     Considering IPPB to deliver a positive-pressure deep breath is correct because when a patient cannot generate adequate inspiratory volumes with incentive spirometry, IPPB provides mechanical positive pressure to expand the atelectatic lung regions.

289. A patient with bronchiectasis uses a PEP device daily. The therapist explains that exhaling against the resistance helps prevent airway collapse and:
     • Promotes movement of air distal to secretions through collateral channels
     • Dries out the secretions
     • Delivers a bronchodilator
     • Measures lung volumes

     Correct answer: Promotes movement of air distal to secretions through collateral channels

     Promoting movement of air distal to secretions through collateral channels is correct because the back pressure of PEP keeps airways open and lets air migrate behind retained mucus through collateral pathways, helping push the secretions toward the central airways.