- Malignant hyperthermia is caused by an inherited defect in which intracellular structure of skeletal muscle?
- The ryanodine receptor of the sarcoplasmic reticulum
- The nicotinic acetylcholine receptor at the motor end plate
- The voltage-gated sodium channel of the sarcolemma
- The mitochondrial electron transport chain
Correct answer: The ryanodine receptor of the sarcoplasmic reticulum
Malignant hyperthermia results from a defective ryanodine receptor (most often an RYR1 mutation) in the sarcoplasmic reticulum of skeletal muscle. When triggered, this abnormal channel allows uncontrolled calcium release, driving sustained contraction and a hypermetabolic state. The motor end plate receptor, sarcolemmal sodium channel, and mitochondrial chain are not the primary genetic defect.
- Which two anesthetic agents are the classic triggers of malignant hyperthermia in a susceptible patient?
- Propofol and remifentanil
- Volatile inhalation agents and succinylcholine
- Ketamine and dexmedetomidine
- Nitrous oxide and rocuronium
Correct answer: Volatile inhalation agents and succinylcholine
The recognized triggers of malignant hyperthermia are the potent volatile inhalation anesthetics and the depolarizing relaxant succinylcholine. These agents provoke pathologic calcium release through the defective ryanodine receptor. Propofol, ketamine, dexmedetomidine, opioids, nitrous oxide, and nondepolarizing relaxants such as rocuronium are considered non-triggering and form the basis of a safe anesthetic for susceptible patients.
- Which finding is typically the earliest and most sensitive clinical sign of acute malignant hyperthermia under general anesthesia?
- A precipitous fall in blood pressure
- An unexplained, rising end-tidal carbon dioxide despite increased ventilation
- A widely fixed and dilated pupil
- A sudden drop in core body temperature
Correct answer: An unexplained, rising end-tidal carbon dioxide despite increased ventilation
The earliest and most sensitive sign of malignant hyperthermia is an unexplained, progressively rising end-tidal carbon dioxide that does not respond to increased minute ventilation, reflecting the hypermetabolic surge in CO2 production. Marked temperature elevation, rigidity, tachycardia, and acidosis follow, but hyperthermia is often a late finding rather than the initial clue.
- What is the mechanism by which dantrolene treats malignant hyperthermia?
- It blocks nicotinic receptors at the neuromuscular junction
- It inhibits calcium release from the sarcoplasmic reticulum by acting on the ryanodine receptor
- It uncouples oxidative phosphorylation to lower heat production
- It increases reuptake of calcium by stimulating the sodium-potassium pump
Correct answer: It inhibits calcium release from the sarcoplasmic reticulum by acting on the ryanodine receptor
Dantrolene works by inhibiting calcium release from the sarcoplasmic reticulum through the ryanodine receptor, reducing the myoplasmic calcium that drives sustained muscle contraction and hypermetabolism. By directly opposing the underlying calcium dysregulation, it halts the malignant hyperthermia cascade. It does not act at the neuromuscular junction or on the sodium-potassium pump.
- A susceptible patient develops malignant hyperthermia. After stopping triggering agents, what is the recommended initial intravenous dose of dantrolene?
- 0.1 mg/kg
- 10 mg/kg
- 2.5 mg/kg
- 0.5 mg/kg
Correct answer: 2.5 mg/kg
The recommended initial dose of dantrolene for malignant hyperthermia is 2.5 mg/kg given intravenously, repeated as needed until the hypermetabolic signs resolve. This dose is large enough to begin suppressing pathologic sarcoplasmic calcium release. The much smaller doses listed would be ineffective, and 10 mg/kg exceeds the usual single starting dose.
- Why does succinylcholine produce a brief period of muscle fasciculations before paralysis?
- It is a depolarizing agent that first opens nicotinic channels and depolarizes the end plate before sustained depolarization blocks further transmission
- It competitively antagonizes acetylcholine without binding the receptor
- It inhibits acetylcholinesterase, transiently flooding the junction with acetylcholine
- It blocks presynaptic calcium channels, briefly increasing acetylcholine release
Correct answer: It is a depolarizing agent that first opens nicotinic channels and depolarizes the end plate before sustained depolarization blocks further transmission
Succinylcholine is a depolarizing neuromuscular blocker that binds and activates the nicotinic receptors, opening channels and depolarizing the motor end plate. This initial depolarization spreads as disorganized fasciculations, then the persistent depolarization renders the membrane unresponsive, producing flaccid paralysis. It is not a competitive antagonist and does not act as a cholinesterase inhibitor.
- Succinylcholine should generally be avoided in a patient with a severe crush injury several days old primarily because of the risk of which complication?
- Prolonged blockade from pseudocholinesterase deficiency
- Profound bradycardia from vagal stimulation
- Life-threatening hyperkalemia from exaggerated potassium release
- Sustained skeletal muscle rigidity of the jaw
Correct answer: Life-threatening hyperkalemia from exaggerated potassium release
In patients with major burns, crush or denervation injuries, or prolonged immobility, upregulation of extrajunctional acetylcholine receptors causes succinylcholine to release a large, potentially lethal amount of potassium, risking hyperkalemic cardiac arrest. This exaggerated potassium efflux, rather than bradycardia, masseter rigidity, or pseudocholinesterase deficiency, is the chief reason to avoid the drug in these settings.
- Propofol produces its hypnotic effect primarily through which receptor mechanism?
- Antagonism of NMDA glutamate receptors
- Agonism at central mu-opioid receptors
- Potentiation of the inhibitory GABA-A receptor, enhancing chloride conductance
- Blockade of central alpha-2 adrenergic receptors
Correct answer: Potentiation of the inhibitory GABA-A receptor, enhancing chloride conductance
Propofol produces hypnosis chiefly by potentiating the inhibitory GABA-A receptor, increasing chloride conductance and hyperpolarizing neurons. This enhancement of inhibitory tone underlies its rapid loss of consciousness. NMDA antagonism characterizes ketamine, mu-opioid agonism describes opioids, and central alpha-2 blockade is not how propofol works.
- The rapid awakening seen after a single induction dose of propofol is best explained by which pharmacokinetic property?
- Irreversible binding to brain receptors that quickly desensitize
- Complete renal excretion of unchanged drug within minutes
- An extremely short elimination half-life of under two minutes
- Rapid redistribution of the drug from the brain to peripheral tissues
Correct answer: Rapid redistribution of the drug from the brain to peripheral tissues
Awakening after a single propofol bolus is due primarily to rapid redistribution of the lipophilic drug from the highly perfused brain into muscle and other peripheral tissues, which quickly lowers brain concentration. Although propofol is also cleared rapidly by metabolism, it is the redistribution phase that terminates the effect of a single dose, not renal excretion or irreversible receptor binding.
- Which hemodynamic effect is most characteristic of a standard induction dose of propofol?
- A decrease in blood pressure from vasodilation and reduced sympathetic tone
- A marked rise in systemic vascular resistance
- A reflex tachycardia that reliably maintains blood pressure
- An increase in myocardial contractility
Correct answer: A decrease in blood pressure from vasodilation and reduced sympathetic tone
Propofol characteristically lowers blood pressure through vasodilation, reduced sympathetic outflow, and mild myocardial depression. It also blunts the baroreflex, so a compensatory tachycardia is often absent, which can deepen hypotension in hypovolemic patients. It does not raise contractility or systemic vascular resistance.
- Etomidate is frequently selected for induction in a hemodynamically unstable patient because of which property?
- It provides profound analgesia in addition to hypnosis
- It reliably suppresses the cortisol stress response for surgery
- It produces marked, beneficial vasodilation
- It maintains cardiovascular stability with minimal effect on blood pressure and heart rate
Correct answer: It maintains cardiovascular stability with minimal effect on blood pressure and heart rate
Etomidate is valued in unstable patients because it provides hypnosis while causing minimal change in blood pressure, heart rate, and contractility, preserving hemodynamic stability. It lacks analgesic properties, and its suppression of adrenal cortisol synthesis is an unwanted adverse effect rather than a reason to choose it. Marked vasodilation is not a feature of etomidate.
- A recognized adverse effect of even a single induction dose of etomidate is transient inhibition of which enzyme?
- Plasma pseudocholinesterase
- Hepatic cytochrome P450 3A4
- 11-beta-hydroxylase in the adrenal cortex
- Carbonic anhydrase in renal tubules
Correct answer: 11-beta-hydroxylase in the adrenal cortex
Etomidate inhibits 11-beta-hydroxylase, an adrenal enzyme required for cortisol synthesis, so even a single induction dose can transiently suppress the cortisol stress response. This adrenal suppression is the main concern with etomidate, particularly in critically ill or septic patients. It does not characteristically inhibit pseudocholinesterase, carbonic anhydrase, or hepatic P450 3A4.
- Ketamine produces anesthesia and analgesia primarily by antagonizing which receptor?
- The GABA-A chloride channel
- The N-methyl-D-aspartate (NMDA) glutamate receptor
- The peripheral histamine H1 receptor
- The beta-2 adrenergic receptor
Correct answer: The N-methyl-D-aspartate (NMDA) glutamate receptor
Ketamine acts mainly as a noncompetitive antagonist at the NMDA glutamate receptor, producing dissociative anesthesia and potent analgesia. This NMDA blockade distinguishes it from the GABA-enhancing intravenous agents. Histamine and beta-2 adrenergic receptors are not its principal sites of action.
- Unlike most induction agents, ketamine tends to increase heart rate and blood pressure. What is the basis for this sympathomimetic effect?
- Direct stimulation of cardiac beta-1 receptors by the drug molecule
- Centrally mediated sympathetic stimulation with inhibition of catecholamine reuptake
- Reflex response to profound ketamine-induced vasodilation
- Blockade of vagal tone at the sinoatrial node
Correct answer: Centrally mediated sympathetic stimulation with inhibition of catecholamine reuptake
Ketamine raises heart rate and blood pressure through centrally mediated sympathetic stimulation and inhibition of norepinephrine reuptake, which increases circulating catecholamine activity. This indirect sympathomimetic action makes it useful when hemodynamic support is desired. In patients with depleted catecholamine reserves, however, ketamine's direct myocardial depressant effect can instead be unmasked.
- Dexmedetomidine produces sedation and analgesia mainly through agonism at which receptor?
- The central alpha-2 adrenergic receptor
- The peripheral alpha-1 adrenergic receptor
- The NMDA glutamate receptor
- The mu-opioid receptor
Correct answer: The central alpha-2 adrenergic receptor
Dexmedetomidine is a highly selective central alpha-2 adrenergic agonist, and stimulation of these receptors in the locus coeruleus reduces sympathetic outflow to produce sedation and analgesia. Its alpha-2 selectivity distinguishes it from alpha-1 agonists, opioids, and NMDA-active drugs, and accounts for its characteristic sedation that resembles natural sleep with preserved arousability.
- Which hemodynamic effect should the anesthetist anticipate during a dexmedetomidine infusion?
- Bradycardia and hypotension from reduced sympathetic outflow
- Tachycardia and hypertension from beta-1 stimulation
- Bronchospasm and increased airway resistance
- Significant respiratory depression with apnea
Correct answer: Bradycardia and hypotension from reduced sympathetic outflow
Dexmedetomidine reduces central sympathetic outflow, so bradycardia and hypotension are the expected hemodynamic effects, sometimes preceded by a transient hypertension from peripheral alpha stimulation during a loading bolus. A notable clinical advantage is that it provides sedation with minimal respiratory depression, unlike many other sedatives.
- The minimal respiratory depression seen with dexmedetomidine compared with propofol or opioids is best explained by which feature?
- It chemically reverses opioid binding at mu receptors
- It increases the medullary respiratory center's sensitivity to carbon dioxide
- It is rapidly metabolized before it reaches the brainstem
- Its sedation works through alpha-2 pathways that do not strongly depress the brainstem respiratory drive
Correct answer: Its sedation works through alpha-2 pathways that do not strongly depress the brainstem respiratory drive
Dexmedetomidine causes little respiratory depression because its sedation is mediated through central alpha-2 pathways that do not markedly suppress the brainstem respiratory centers, unlike GABAergic agents and opioids. This allows sedation while patients continue to breathe spontaneously, making it useful for procedures requiring an unsupported airway. It does not increase CO2 sensitivity or reverse opioids.
- Nitrous oxide can rapidly enlarge an air-filled space such as a pneumothorax during anesthesia because of which property?
- It is metabolized into a gas that accumulates in closed spaces
- It is many times more soluble in blood than nitrogen, so it diffuses into the space faster than nitrogen leaves
- It chemically reacts with tissue to generate additional gas volume
- It is far less soluble than nitrogen and cannot enter closed spaces
Correct answer: It is many times more soluble in blood than nitrogen, so it diffuses into the space faster than nitrogen leaves
Nitrous oxide is roughly thirty times more soluble in blood than nitrogen, so it diffuses into an air-filled cavity faster than the resident nitrogen can leave. The net inflow expands or pressurizes closed spaces such as a pneumothorax, bowel gas, or middle ear, which is why nitrous oxide is avoided in those settings. It is not metabolized to a gas or chemically generative.
- Diffusion hypoxia at the end of a nitrous oxide anesthetic occurs by which mechanism?
- Nitrous oxide chemically binds hemoglobin and prevents oxygen carriage
- Nitrous oxide rapidly floods out of the blood into the alveoli, diluting alveolar oxygen if the patient breathes room air
- Nitrous oxide causes prolonged bronchospasm that limits oxygen uptake
- Nitrous oxide stimulates excessive oxygen consumption during emergence
Correct answer: Nitrous oxide rapidly floods out of the blood into the alveoli, diluting alveolar oxygen if the patient breathes room air
Diffusion hypoxia happens when nitrous oxide is discontinued and large volumes rapidly leave the blood and pour into the alveoli, diluting alveolar oxygen and carbon dioxide. If the patient is breathing room air, this dilution can transiently lower arterial oxygenation, which is why supplemental oxygen is given during emergence. It does not bind hemoglobin or raise oxygen consumption.
- Local anesthetics produce conduction block in nerves by acting on which target?
- Voltage-gated sodium channels, preventing the influx that generates the action potential
- Potassium channels, prolonging repolarization
- GABA-A receptors on the nerve membrane
- Calcium channels at the presynaptic terminal
Correct answer: Voltage-gated sodium channels, preventing the influx that generates the action potential
Local anesthetics bind voltage-gated sodium channels from the intracellular side and block the sodium influx required to generate and propagate the action potential, producing reversible conduction block. By preventing depolarization rather than acting on potassium, calcium, or GABA channels, they interrupt impulse transmission along the nerve.
- Why does a local anesthetic work poorly in inflamed, acidic tissue such as an abscess?
- Inflammation destroys the sodium channels the drug targets
- The acidic environment denatures the local anesthetic molecule
- Acidic pH increases the ionized fraction of the drug, reducing the amount that can cross the nerve membrane
- Inflamed tissue lacks the receptors needed for binding
Correct answer: Acidic pH increases the ionized fraction of the drug, reducing the amount that can cross the nerve membrane
Local anesthetics are weak bases, and the acidic pH of inflamed tissue shifts more of the drug to its ionized, charged form. Only the un-ionized form crosses the lipid nerve membrane to reach its intracellular site, so less drug penetrates and the block is less effective. The channels and receptors are not destroyed, and the molecule is not denatured.
- Intravenous lipid emulsion rescue therapy reverses severe local anesthetic systemic toxicity primarily by which proposed mechanism?
- Directly blocking sodium channels to oppose the local anesthetic
- Acting as a lipid sink that sequesters lipophilic local anesthetic away from cardiac tissue
- Stimulating hepatic metabolism of the local anesthetic
- Reversing the local anesthetic's binding at the GABA receptor
Correct answer: Acting as a lipid sink that sequesters lipophilic local anesthetic away from cardiac tissue
Intravenous lipid emulsion is thought to work mainly as a lipid sink, creating an expanded plasma lipid phase that draws lipophilic local anesthetic out of cardiac and neural tissue, along with metabolic and cardiotonic effects. By lowering the free drug concentration at the heart, it can restore cardiac function in severe toxicity. It does not block sodium channels or accelerate hepatic metabolism.
- Phenylephrine raises blood pressure during anesthesia primarily through which action?
- Beta-1 stimulation that increases heart rate and contractility
- Beta-2 stimulation causing arteriolar dilation and reflex pressure rise
- Selective alpha-1 agonism causing peripheral vasoconstriction
- Direct release of stored norepinephrine from nerve terminals
Correct answer: Selective alpha-1 agonism causing peripheral vasoconstriction
Phenylephrine is a selective alpha-1 adrenergic agonist that raises blood pressure by causing peripheral arteriolar vasoconstriction and increasing systemic vascular resistance. Because it does not stimulate beta receptors, it often produces a reflex bradycardia rather than tachycardia. It acts directly on alpha-1 receptors rather than by releasing endogenous norepinephrine.
- After giving phenylephrine to treat hypotension, the anesthetist notes the heart rate has slowed. What best explains this reflex bradycardia?
- Phenylephrine directly stimulates the vagus nerve
- The rise in blood pressure triggers a baroreceptor-mediated increase in vagal tone
- Phenylephrine blocks cardiac beta-1 receptors
- Phenylephrine depletes catecholamines at the sinoatrial node
Correct answer: The rise in blood pressure triggers a baroreceptor-mediated increase in vagal tone
Phenylephrine raises blood pressure by alpha-1 vasoconstriction, and the higher pressure stretches the baroreceptors, which reflexly increase vagal tone and slow the heart. This baroreceptor-mediated reflex bradycardia, not direct vagal stimulation or beta-blockade, accounts for the drop in heart rate that commonly follows a phenylephrine bolus.
- Ephedrine differs pharmacologically from phenylephrine chiefly because ephedrine does what?
- Acts only on beta-2 receptors to cause bronchodilation
- Is a selective alpha-1 agonist with no beta activity
- Has no effect on heart rate or contractility
- Acts indirectly by releasing endogenous norepinephrine and stimulates both alpha and beta receptors
Correct answer: Acts indirectly by releasing endogenous norepinephrine and stimulates both alpha and beta receptors
Ephedrine works largely by an indirect mechanism, releasing stored norepinephrine, and it stimulates both alpha and beta receptors. As a result it raises blood pressure while also tending to increase heart rate and contractility, unlike the pure alpha-1 agonist phenylephrine. Because it depends on endogenous catecholamine stores, repeated doses can show tachyphylaxis.
- Protamine is administered after cardiopulmonary bypass to neutralize the anticoagulant effect of which drug?
- Warfarin
- Unfractionated heparin
- Aspirin
- Tranexamic acid
Correct answer: Unfractionated heparin
Protamine is a positively charged protein that binds and neutralizes the negatively charged unfractionated heparin molecule, reversing its anticoagulant effect after procedures such as cardiopulmonary bypass. It does not reverse warfarin, which is managed with vitamin K or factor products, nor does it counteract aspirin or tranexamic acid.
- A patient receiving protamine for heparin reversal suddenly develops hypotension, bradycardia, and elevated pulmonary artery pressure. This presentation is most consistent with which reaction?
- An adverse hemodynamic reaction to protamine administration
- An expected therapeutic response to heparin neutralization
- Acute heparin rebound anticoagulation
- A normal effect of restoring coagulation
Correct answer: An adverse hemodynamic reaction to protamine administration
Rapid protamine administration can cause adverse reactions including systemic hypotension, and a more severe form produces pulmonary vasoconstriction with pulmonary hypertension and right heart strain. These hemodynamic disturbances, often worsened by fast injection, are why protamine is given slowly. They are not the intended effect of heparin neutralization or a sign of heparin rebound.
- Serotonin syndrome may develop when an anesthetic-related agent is combined with a patient's chronic antidepressant. Which of the following drugs is most associated with precipitating this interaction?
- Vecuronium
- Glycopyrrolate
- Meperidine
- Cisatracurium
Correct answer: Meperidine
Meperidine has serotonergic activity and is well recognized for precipitating serotonin syndrome when combined with monoamine oxidase inhibitors or other serotonergic antidepressants. The neuromuscular blockers and the anticholinergic glycopyrrolate listed do not carry this serotonergic risk, making meperidine the agent of concern in a patient on antidepressant therapy.
- Which gas law explains why the volume of gas in an endotracheal tube cuff increases as the surrounding pressure decreases at altitude, with temperature held constant?
- Boyle's law
- Henry's law
- Charles's law
- Graham's law
Correct answer: Boyle's law
Boyle's law states that at constant temperature the volume of a fixed mass of gas is inversely proportional to its pressure, so as ambient pressure falls the gas volume rises. This explains expansion of a cuff or other gas-filled space at altitude. Charles's law relates volume to temperature, Henry's law concerns solubility, and Graham's law describes diffusion rates.
- Henry's law, applied to anesthetic gases, states that the amount of a gas dissolved in blood is proportional to what?
- The partial pressure of that gas above the liquid
- The molecular weight of the gas
- The absolute temperature of the blood alone
- The total volume of the lungs
Correct answer: The partial pressure of that gas above the liquid
Henry's law states that, at a given temperature, the quantity of a gas dissolved in a liquid is directly proportional to the partial pressure of that gas in contact with the liquid. This relationship governs how anesthetic gases dissolve in blood and underlies uptake and distribution. Molecular weight relates to diffusion, and lung volume and temperature alone do not define the law.
- Naloxone reverses opioid-induced respiratory depression by which pharmacologic action?
- Stimulating the medullary respiratory center as a direct analeptic
- Inhibiting the metabolism of the opioid so it is cleared faster
- Agonizing kappa-opioid receptors to offset mu effects
- Competitively antagonizing the opioid at the mu-opioid receptor
Correct answer: Competitively antagonizing the opioid at the mu-opioid receptor
Naloxone is a competitive antagonist that displaces the opioid from the mu-opioid receptor, reversing respiratory depression, sedation, and analgesia. Because its duration is often shorter than that of many opioids, re-sedation can occur and redosing may be needed. It does not directly stimulate the respiratory center or speed opioid metabolism.
- An opioid such as buprenorphine is described as a partial agonist at the mu-opioid receptor. What does this mean clinically?
- It produces no analgesic effect at any dose
- It blocks all opioid receptors with no intrinsic activity
- It only works when combined with a full agonist
- It binds the receptor and produces a submaximal effect with a ceiling, even at high doses
Correct answer: It binds the receptor and produces a submaximal effect with a ceiling, even at high doses
A partial agonist like buprenorphine binds the mu-opioid receptor and produces a submaximal effect that plateaus at a ceiling no matter how much more is given. Because of its high affinity, it can also blunt the effect of subsequently administered full agonists. It does have analgesic activity, distinguishing it from a pure antagonist.
- A co-oximeter differs from a standard bedside pulse oximeter in that it can quantify dyshemoglobins. Which result would a co-oximeter provide that a conventional two-wavelength pulse oximeter cannot?
- The separate fractional percentages of oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, and methemoglobin
- The end-tidal carbon dioxide concentration
- The cardiac output by thermodilution
- The systemic vascular resistance
Correct answer: The separate fractional percentages of oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, and methemoglobin
A laboratory co-oximeter uses multiple wavelengths of light to distinguish and report the individual fractions of oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, and methemoglobin, giving a true fractional oxygen saturation. A conventional two-wavelength pulse oximeter measures only the ratio of oxyhemoglobin to reduced hemoglobin and therefore cannot separate out the dyshemoglobins, which is why co-oximetry is needed when carbon monoxide or methemoglobin is suspected.
- A patient who received a topical benzocaine spray for airway anesthesia shows a pulse oximeter reading that plateaus near 85 percent and does not improve with 100 percent oxygen, while the arterial blood appears chocolate-brown. The pulse oximeter behaves this way during significant methemoglobinemia because methemoglobin:
- Absorbs almost no light at the wavelengths the oximeter uses
- Absorbs red and infrared light similarly, driving the reading toward a fixed value near 85 percent regardless of true saturation
- Causes the probe to lose its pulsatile signal entirely
- Increases the oxygen content of the blood
Correct answer: Absorbs red and infrared light similarly, driving the reading toward a fixed value near 85 percent regardless of true saturation
Methemoglobin absorbs red and infrared light to nearly equal degrees, so as its level rises the absorbance ratio is forced toward unity and the displayed saturation tends to plateau around 85 percent independent of the actual arterial oxygenation. A reading stuck near 85 percent that fails to rise with supplemental oxygen, alongside chocolate-brown blood, points to methemoglobinemia and warrants co-oximetry and treatment.
- During an anesthesia machine preuse checkout, the provider closes the adjustable pressure-limiting valve, occludes the Y-piece, and fills the circuit until pressure reaches about 30 cm H2O. The purpose of watching whether that pressure holds is to:
- Calibrate the capnograph
- Verify breathing-circuit integrity by detecting a leak in the patient circuit
- Test the function of the carbon dioxide absorbent
- Confirm the oxygen analyzer is reading correctly
Correct answer: Verify breathing-circuit integrity by detecting a leak in the patient circuit
Pressurizing the closed circuit to roughly 30 cm H2O and confirming that the pressure is sustained checks the breathing circuit for leaks at connections, the absorber, and the bag; a falling pressure reveals a leak that must be found before anesthesia. This positive-pressure leak check of the patient circuit is distinct from the low-pressure leak test of the machine internals and from absorbent, capnograph, or analyzer checks.
- The second-stage oxygen pressure regulator, sometimes called the oxygen flow regulator, on an anesthesia machine maintains the oxygen flowmeter at a constant working pressure of approximately:
- 16 pounds per square inch
- 100 pounds per square inch
- 745 pounds per square inch
- 2000 pounds per square inch
Correct answer: 16 pounds per square inch
A second-stage regulator further reduces the roughly 45 to 55 pounds per square inch pipeline or first-stage oxygen pressure to a lower, constant value near 14 to 16 pounds per square inch supplied to the flowmeter, so that the flow stays stable despite normal fluctuations in supply pressure. This is well below the 745 pounds per square inch of a nitrous oxide cylinder and the roughly 2000 pounds per square inch of a full oxygen cylinder.
- A full E-cylinder of oxygen contains about 660 liters of gas at roughly 2000 pounds per square inch. If the cylinder gauge now reads 1000 pounds per square inch and the patient is receiving oxygen at 6 liters per minute, approximately how long can the cylinder supply that flow?
- About 11 minutes
- About 30 minutes
- About 55 minutes
- About 110 minutes
Correct answer: About 55 minutes
Because oxygen is stored as a compressed gas, contents fall in proportion to pressure, so a gauge of 1000 of 2000 pounds per square inch means roughly half of 660 liters, about 330 liters, remain. Dividing 330 liters by a 6 liter-per-minute flow yields approximately 55 minutes of supply, illustrating how the proportional pressure-to-content relationship lets the provider estimate remaining cylinder time.
- A nitrous oxide E-cylinder pressure gauge has read a steady 745 pounds per square inch for most of a long anesthetic and then begins to fall rapidly. This pattern occurs because nitrous oxide is stored as a liquid, meaning a falling gauge now indicates that:
- The cylinder is overpressurized
- Nearly all the liquid has vaporized and the cylinder is close to empty
- The cylinder is approximately three-quarters full
- The regulator has failed
Correct answer: Nearly all the liquid has vaporized and the cylinder is close to empty
Nitrous oxide is stored partly as liquid, so the gauge reflects the vapor pressure above the liquid and stays near 745 pounds per square inch as long as any liquid remains. Only when essentially all the liquid has been consumed does the gauge begin to drop, so a falling nitrous oxide gauge is a late warning that the cylinder is nearly empty, in contrast to oxygen, whose gauge declines steadily throughout use.
- The diameter index safety system is a keyed-connection safeguard that prevents misconnection of:
- High-pressure cylinders to the hanger yoke
- Low-pressure pipeline hoses and their threaded connectors to the wrong gas inlet on the machine
- The vaporizer to its mounting manifold
- The endotracheal tube to the breathing circuit
Correct answer: Low-pressure pipeline hoses and their threaded connectors to the wrong gas inlet on the machine
The diameter index safety system uses gas-specific, noninterchangeable threaded fittings on the low-pressure pipeline hoses and wall or machine inlets, so an oxygen hose cannot be threaded into a nitrous oxide inlet. It complements the pin index safety system, which performs the analogous keying for high-pressure cylinders mounted on the yoke, together reducing the chance of a crossed gas connection.
- A capnogram shows a small notch or cleft, sometimes called a curare cleft, dipping into the alveolar plateau of a mechanically ventilated patient. This finding most specifically indicates:
- Exhaustion of the carbon dioxide absorbent
- A spontaneous inspiratory effort by the patient breaking through the controlled breath, often signaling returning muscle activity
- Esophageal intubation
- A leak in the sampling line
Correct answer: A spontaneous inspiratory effort by the patient breaking through the controlled breath, often signaling returning muscle activity
A cleft in the alveolar plateau appears when the patient makes a spontaneous diaphragmatic effort during a mechanically delivered breath, briefly entraining fresh gas and dipping the carbon dioxide tracing. Often termed a curare cleft, its appearance can signal that neuromuscular blockade is wearing off and that additional relaxant or adjustment is needed, distinguishing it from absorbent exhaustion or a sampling leak.
- An anesthesia provider notes a widening gradient between the end-tidal carbon dioxide and the arterial carbon dioxide measured on a blood gas during a case complicated by a sudden drop in cardiac output. The most likely reason end-tidal carbon dioxide underestimates arterial carbon dioxide in this situation is:
- Increased carbon dioxide production
- Increased alveolar dead space from reduced pulmonary perfusion, so less carbon dioxide reaches the exhaled gas
- Hyperventilation lowering arterial carbon dioxide
- A calibration error in the capnograph
Correct answer: Increased alveolar dead space from reduced pulmonary perfusion, so less carbon dioxide reaches the exhaled gas
End-tidal carbon dioxide normally runs a few millimeters of mercury below arterial carbon dioxide, but the gradient widens when alveolar dead space increases, as when low cardiac output, pulmonary embolism, or hypovolemia reduces perfusion to ventilated alveoli. Poorly perfused alveoli contribute little carbon dioxide to the exhaled gas, lowering the end-tidal value relative to the arterial level, so a sudden widening gradient is a clue to a perfusion problem.
- A train-of-four ratio compares the height of the fourth twitch to the first. During a nondepolarizing block, the train-of-four count (number of visible twitches) disappears in a characteristic order, with the fourth twitch lost first. Roughly what level of receptor occupancy corresponds to loss of all four twitches?
- About 50 percent receptor occupancy
- About 70 percent receptor occupancy
- About 100 percent (complete) receptor occupancy
- About 25 percent receptor occupancy
Correct answer: About 100 percent (complete) receptor occupancy
As nondepolarizing block deepens, twitches are lost from the fourth down to the first; the fourth disappears at roughly 75 percent occupancy, and all four are gone when occupancy approaches 90 to 100 percent. Loss of every train-of-four twitch therefore reflects near-complete receptor blockade, after which only the post-tetanic count can gauge depth, illustrating why the count guides reversal timing.
- During emergence, an anesthesia provider applies a sustained 5-second 50-hertz tetanic stimulus and observes that the contraction is well maintained without fade. This sustained tetanus most reliably indicates:
- A profound nondepolarizing block
- Adequate recovery of neuromuscular function with little residual nondepolarizing block
- A phase II block from succinylcholine
- Equipment failure of the nerve stimulator
Correct answer: Adequate recovery of neuromuscular function with little residual nondepolarizing block
A tetanic contraction that is sustained without fade reflects sufficient presynaptic acetylcholine reserve to maintain repetitive firing, which corresponds to substantial recovery from nondepolarizing blockade. However, subjective tetanic assessment can miss fine degrees of residual weakness, so quantitative monitoring confirming a train-of-four ratio of at least 0.9 remains the most reliable evidence of adequate recovery before extubation.
- On a modern anesthesia machine equipped with electronic flow control, the auxiliary common gas outlet and the ascending bellows are monitored, but the inspired oxygen sensor remains mandatory. According to standard monitoring guidance, an enabled low-inspired-oxygen alarm is required because it is the only safeguard that directly detects:
- A disconnection of the breathing circuit
- A delivered hypoxic gas concentration regardless of its cause
- Exhaustion of the carbon dioxide absorbent
- An elevated airway pressure
Correct answer: A delivered hypoxic gas concentration regardless of its cause
The inspired oxygen analyzer with an enabled low-concentration alarm is the final safeguard that measures the actual oxygen concentration delivered to the patient, catching a hypoxic mixture whether it arises from a pipeline crossover, a third gas, or operator error, none of which the pressure-based fail-safe or proportioning systems can detect. This is why an oxygen analyzer is a required monitor whenever an anesthesia machine is in use.
- A heated humidifier added to the inspiratory limb of a circle circuit provides active humidification. Compared with a passive heat and moisture exchanger, a heated humidifier is preferred for prolonged ventilation chiefly because it:
- Adds no water to the circuit
- Delivers higher absolute humidity and warming without the added airway dead space of a passive device
- Eliminates the need for a carbon dioxide absorbent
- Functions only with low fresh gas flows
Correct answer: Delivers higher absolute humidity and warming without the added airway dead space of a passive device
An active heated humidifier vaporizes water into the inspired gas, achieving higher absolute humidity and more effective warming than a passive heat and moisture exchanger and without adding dead space at the airway, which benefits patients needing prolonged or high-minute-ventilation support. Its drawbacks include the need for a power source, potential for condensation and circuit water, and a small risk of overheating, so it is reserved for situations where passive humidification is inadequate.
- A bronchial blocker is being positioned for one-lung ventilation. To allow the operative lung to deflate after the balloon is inflated in the correct mainstem bronchus, the bronchial blocker is designed with:
- A second inflatable cuff at its tip
- A small central channel that permits egress of gas and suction to collapse the isolated lung
- An integrated carbon dioxide sensor
- A built-in light source for illumination
Correct answer: A small central channel that permits egress of gas and suction to collapse the isolated lung
A bronchial blocker contains a narrow central lumen through which trapped gas can escape and suction can be applied to hasten collapse of the isolated lung once the balloon occludes the bronchus. Because this channel is small, lung deflation is generally slower and less complete than with a double-lumen tube, which is a recognized trade-off of the blocker technique for lung isolation.
- When sizing a double-lumen endobronchial tube, a left-sided tube is favored over a right-sided tube for most cases primarily because:
- The left mainstem bronchus is shorter than the right
- The right upper lobe bronchus arises close to the carina, making right-sided tube placement prone to obstructing that lobe
- Left-sided tubes are easier to manufacture
- The left lung is always the operative side
Correct answer: The right upper lobe bronchus arises close to the carina, making right-sided tube placement prone to obstructing that lobe
Because the right upper lobe bronchus takes off only a short distance from the carina, a right-sided double-lumen tube must align a small ventilation slot precisely with that orifice and is easily malpositioned, risking right upper lobe collapse. The longer left mainstem bronchus gives more margin for the bronchial cuff, so a left-sided tube is the default choice unless left-sided surgery or anatomy contraindicates it.
- A laryngeal mask airway is generally considered a relatively poor choice, compared with a cuffed endotracheal tube, for a patient at high risk of aspiration because the supraglottic device:
- Cannot deliver oxygen
- Seals above the glottis and does not protect the airway from regurgitated gastric contents as a cuffed tube does
- Always causes laryngospasm
- Cannot be used with volatile anesthetics
Correct answer: Seals above the glottis and does not protect the airway from regurgitated gastric contents as a cuffed tube does
A standard laryngeal mask airway sits above the glottic opening and provides only a perilaryngeal seal, so it does not reliably prevent aspiration of regurgitated gastric contents the way a cuff seated within the trachea does. For patients with a full stomach, significant reflux, or other aspiration risk, a cuffed endotracheal tube placed by rapid sequence technique is preferred, though second-generation supraglottic devices with a gastric drainage port offer partial mitigation.
- A provider preparing for an awake fiberoptic intubation chooses a flexible bronchoscope partly because it can be used to confirm endotracheal tube position after placement. Through the scope, correct tracheal placement is confirmed by visualizing:
- The vocal cords from above only
- The tracheal rings and the carina distal to the tube tip
- The esophageal mucosa
- The nasopharynx
Correct answer: The tracheal rings and the carina distal to the tube tip
Passing the flexible bronchoscope through the tube and seeing the characteristic anterior tracheal rings and the bifurcation of the carina beyond the tube tip confirms tracheal placement and appropriate depth above the carina. Visualizing smooth, featureless esophageal mucosa instead would indicate esophageal placement, so direct bronchoscopic confirmation is a definitive equipment-based check of tube position.
- A Bougie (tracheal tube introducer) assists intubation when the glottic view is poor. Tactile confirmation that the bougie has entered the trachea rather than the esophagus is provided by:
- A drop in oxygen saturation
- Feeling clicks as the angled tip passes over the tracheal rings, and holdup as it reaches a smaller distal airway
- A rise in end-tidal carbon dioxide before the tube is placed
- Resistance only at the lips
Correct answer: Feeling clicks as the angled tip passes over the tracheal rings, and holdup as it reaches a smaller distal airway
When the coude-tipped bougie enters the trachea, the operator can feel a series of clicks as the angled tip bumps along the anterior tracheal cartilage rings and then experiences distal holdup when the tip wedges in a smaller bronchus, neither of which occurs in the smooth, distensible esophagus. These tactile cues guide successful tube railroading over the bougie when direct visualization of the cords is limited.
- A Macintosh blade is selected for a routine direct laryngoscopy. Correct placement of the curved blade tip to obtain the best view of the glottis is:
- Directly beneath the epiglottis to lift it
- Into the vallecula, with upward and forward lift tensioning the hyoepiglottic ligament to elevate the epiglottis indirectly
- Against the posterior pharyngeal wall
- Inside the esophageal inlet
Correct answer: Into the vallecula, with upward and forward lift tensioning the hyoepiglottic ligament to elevate the epiglottis indirectly
The curved Macintosh blade tip is seated in the vallecula, the space between the tongue base and epiglottis, and lifting along the blade's axis tenses the hyoepiglottic ligament so the epiglottis swings up to reveal the cords. This indirect epiglottic elevation contrasts with the straight Miller blade, which is passed under the epiglottis to lift it directly, the two techniques matching their respective blade shapes.
- Nitrous oxide is being used during a long case with an endotracheal tube whose cuff was inflated with air. Over time the cuff pressure tends to rise because nitrous oxide:
- Is absorbed by the cuff material and shrinks it
- Diffuses from the blood and surrounding gas into the air-filled cuff faster than the cuff's nitrogen diffuses out, increasing cuff volume and pressure
- Reacts chemically with the cuff to generate heat
- Cools the cuff and contracts the gas
Correct answer: Diffuses from the blood and surrounding gas into the air-filled cuff faster than the cuff's nitrogen diffuses out, increasing cuff volume and pressure
Nitrous oxide is far more soluble and diffuses more readily than nitrogen, so when it is present in the inspired gas it enters an air-filled endotracheal tube cuff faster than the cuff's nitrogen leaves, progressively raising cuff volume and pressure. This can push tracheal wall pressure above the safe range, so cuff pressure should be monitored with a manometer or the cuff filled with a gas mixture matching the inspired gas during prolonged nitrous oxide anesthesia.
- An oscillometric noninvasive blood pressure monitor repeatedly fails to obtain a reading in a patient with a markedly irregular rhythm from atrial fibrillation. The most likely reason is that:
- Irregular beat-to-beat variation disrupts the algorithm that depends on consistent pulse oscillation amplitudes
- The cuff is too large for any patient
- Atrial fibrillation abolishes arterial pressure
- The monitor measures only venous pressure
Correct answer: Irregular beat-to-beat variation disrupts the algorithm that depends on consistent pulse oscillation amplitudes
Oscillometric monitors derive blood pressure by comparing the changing amplitude of successive pulse oscillations as the cuff deflates, so beat-to-beat irregularity from atrial fibrillation or frequent ectopy produces inconsistent oscillations that confuse the algorithm and prolong or prevent measurement. In such patients an invasive arterial line may be needed for reliable, continuous pressure monitoring.
- To minimize hydrostatic error, an automated noninvasive blood pressure cuff should be applied to a limb positioned at the level of the heart. If the cuffed arm hangs well below heart level during measurement, the reading will be:
- Falsely low
- Falsely high because of the added hydrostatic column of blood
- Unaffected by limb position
- Displayed as an error only
Correct answer: Falsely high because of the added hydrostatic column of blood
When the cuffed limb is positioned below the level of the heart, the weight of the additional column of blood adds hydrostatic pressure and the device reports a falsely elevated blood pressure; conversely, a limb held above heart level reads falsely low. Keeping the cuff at heart level, or correcting for the height difference, preserves accuracy, an effect analogous to leveling an invasive transducer at the phlebostatic axis.
- During invasive arterial pressure monitoring, a fast-flush (square-wave) test that produces several rapid oscillations before settling indicates an underdamped system. An underdamped arterial trace tends to:
- Underestimate systolic pressure and overestimate diastolic pressure
- Overestimate systolic pressure and underestimate diastolic pressure (overshoot)
- Report mean pressure as zero
- Have no effect on the displayed values
Correct answer: Overestimate systolic pressure and underestimate diastolic pressure (overshoot)
An underdamped system oscillates excessively after a flush, exaggerating the peaks and troughs of the waveform so that systolic pressure is overestimated and diastolic pressure underestimated, while mean pressure stays relatively accurate. Underdamping arises from stiff, overly long tubing or excessive stopcocks, whereas overdamping from bubbles or clots blunts the waveform, so the flush test distinguishes the two faults.
- An invasive pressure monitoring system is set up with the transducer, tubing, and flush solution. The continuous flush device in this setup is designed to:
- Deliver a slow, continuous infusion of pressurized saline (about 3 milliliters per hour) to keep the catheter patent
- Inject medications into the artery automatically
- Measure the cardiac output
- Warm the patient's blood
Correct answer: Deliver a slow, continuous infusion of pressurized saline (about 3 milliliters per hour) to keep the catheter patent
The continuous flush device, supplied from a pressurized bag, delivers a small continuous trickle of flush solution, typically around 3 milliliters per hour, to prevent clotting and maintain patency of the arterial or central catheter without distorting the pressure waveform. Squeezing the manual flush valve briefly delivers a larger bolus used for the square-wave dynamic-response test, not for routine medication delivery.
- An anesthesia machine ventilator alarm announces high peak airway pressure during volume-controlled ventilation while the plateau pressure remains relatively normal. This pattern most specifically suggests:
- A decrease in lung or chest wall compliance
- An increase in airway resistance, such as from a kinked tube, secretions, or bronchospasm
- A circuit disconnection
- Exhausted soda lime
Correct answer: An increase in airway resistance, such as from a kinked tube, secretions, or bronchospasm
Peak inspiratory pressure reflects both airway resistance and compliance, while plateau pressure reflects compliance alone, so a high peak with a near-normal plateau isolates the problem to elevated airway resistance from causes like a kinked or obstructed tube, mucus plugging, or bronchospasm. When both peak and plateau rise together, reduced compliance from pneumothorax, edema, or mainstem intubation is more likely, so comparing the two pressures localizes the fault.
- A piston-driven anesthesia ventilator is used instead of a traditional bellows ventilator. A clinically relevant advantage of the piston design is that it:
- Requires no electrical power
- Uses no driving gas, conserving oxygen and delivering more consistent tidal volumes including to low-compliance lungs
- Eliminates the need for a fresh gas source
- Cannot deliver positive end-expiratory pressure
Correct answer: Uses no driving gas, conserving oxygen and delivering more consistent tidal volumes including to low-compliance lungs
A piston ventilator drives the breath with an electrically powered piston rather than a pneumatically compressed bellows, so it consumes no driving gas, conserving oxygen, and can deliver more accurate and consistent tidal volumes across a range of compliances. Because it is electrically driven and often quieter, providers must remain attentive to circuit integrity and rely on alarms, since the piston gives less obvious visual feedback than a rising and falling bellows.
- Fresh gas flow compensation (fresh gas decoupling) is incorporated into many modern anesthesia ventilators. Without this feature, increasing the fresh gas flow during volume-controlled ventilation would tend to:
- Have no effect on delivered tidal volume
- Add to the set tidal volume, increasing the volume actually delivered to the patient
- Decrease the delivered tidal volume
- Stop the ventilator
Correct answer: Add to the set tidal volume, increasing the volume actually delivered to the patient
In older designs the fresh gas flowing into the circuit during inspiration was added to the bellows-driven breath, so raising the fresh gas flow inadvertently increased the delivered tidal volume, risking barotrauma or volutrauma. Fresh gas decoupling or compensation isolates the fresh gas inflow from the inspiratory volume so that the set tidal volume is delivered accurately regardless of fresh gas flow changes.
- During electrosurgery, a surgeon requests use of bipolar rather than monopolar cautery in a patient with a cardiac implantable electronic device. Bipolar cautery reduces electromagnetic interference risk because the current:
- Is much larger than monopolar current
- Flows only between the two tips of the bipolar forceps rather than traveling through the patient's body to a distant return pad
- Does not generate any heat
- Travels directly through the heart
Correct answer: Flows only between the two tips of the bipolar forceps rather than traveling through the patient's body to a distant return pad
In bipolar electrosurgery the radiofrequency current passes only between the two limbs of the forceps across the small tissue grasped between them, so it does not traverse the patient's torso toward a dispersive return pad. This confined current path greatly reduces electromagnetic interference reaching a pacemaker or implanted defibrillator and also removes the need for a return electrode, making bipolar preferable near such devices.
- A contact-quality monitoring (return electrode monitoring) system on a modern electrosurgical unit improves safety by:
- Increasing the cutting power automatically
- Continuously checking impedance through the split dispersive pad and disabling output if pad contact becomes inadequate, preventing return-site burns
- Measuring the patient's blood pressure
- Filtering electrocardiogram artifact
Correct answer: Continuously checking impedance through the split dispersive pad and disabling output if pad contact becomes inadequate, preventing return-site burns
Return electrode contact-quality monitoring uses a dual-section dispersive pad and continuously measures the impedance between its halves; if the pad lifts or loses adequate skin contact, the impedance changes and the generator alarms and shuts off output. By stopping current before the return current density rises enough to burn the patient, this system addresses one of the classic electrosurgical injury mechanisms.
- In ultrasound-guided regional anesthesia, the needle is described as in-plane when it is:
- Inserted perpendicular to the probe so only a cross-sectional dot is seen
- Aligned along the long axis of the transducer so its entire shaft and tip are visualized as it advances
- Advanced without any ultrasound guidance
- Held stationary while the probe moves
Correct answer: Aligned along the long axis of the transducer so its entire shaft and tip are visualized as it advances
An in-plane approach keeps the needle aligned with the long axis of the ultrasound beam so the full length of the shaft and the tip are continuously imaged, allowing the operator to track the advancing tip relative to nerves and vessels. An out-of-plane approach crosses the beam and shows only a bright dot, making it harder to know whether that dot is the true tip, which is why in-plane visualization is favored for accurate, safe needle placement.
- Color Doppler is applied during ultrasound-guided vascular access to distinguish an artery from a vein. Doppler imaging detects blood flow by measuring:
- The temperature of the flowing blood
- The frequency shift of ultrasound echoes reflected from moving red blood cells
- The electrical activity of the vessel wall
- The oxygen saturation within the vessel
Correct answer: The frequency shift of ultrasound echoes reflected from moving red blood cells
Doppler ultrasound relies on the Doppler effect, detecting the shift in frequency between the transmitted beam and the echoes returning from moving red blood cells, with the magnitude and direction of the shift encoded as color to display flow. This lets the provider identify pulsatile arterial flow versus phasic venous flow and confirm vessel patency, complementing the compressibility test that distinguishes a collapsible vein from a pulsatile artery.
- A provider scores a Mallampati class I airway during the preoperative examination. Which oropharyngeal structures are visible in this most favorable grade?
- The soft palate, fauces, uvula, and tonsillar pillars are all visible
- Only the soft palate and the base of the uvula are visible
- Only the hard palate is visible
- The soft palate, fauces, and uvula are visible but the pillars are concealed
Correct answer: The soft palate, fauces, uvula, and tonsillar pillars are all visible
A Mallampati class I view reveals the full pharynx including the soft palate, fauces, uvula, and tonsillar pillars, representing the most favorable grade and the lowest predicted difficulty of laryngoscopy. Class II hides the pillars, class III shows only the soft palate and the base of the uvula, and class IV shows only the hard palate, so visibility of all four structures defines class I.
- While anticipating a difficult intubation, a provider asks an assistant to apply backward, upward, and rightward pressure on the thyroid cartilage during laryngoscopy. What is the purpose of this maneuver?
- To occlude the esophagus and prevent regurgitation
- To improve the laryngeal view by displacing the larynx into the line of sight
- To confirm endotracheal tube placement by feel
- To break a laryngospasm at the cords
Correct answer: To improve the laryngeal view by displacing the larynx into the line of sight
External laryngeal manipulation applying backward, upward, and rightward pressure on the thyroid cartilage shifts the larynx posteriorly and to the right to bring the glottis into the laryngoscopist's view, frequently upgrading a poor Cormack-Lehane grade. This differs from cricoid pressure, which targets the cricoid cartilage to occlude the esophagus, and it neither confirms tube position nor treats laryngospasm.
- Following an induction and paralysis in a predicted easy airway, the patient cannot be intubated after the first attempt but is easily mask ventilated. According to the difficult airway algorithm, what is the most appropriate next step?
- Proceed immediately to a surgical cricothyrotomy
- Continue identical repeated laryngoscopy attempts with the same blade and position
- Optimize conditions and limit attempts while maintaining oxygenation, considering an adjunct, a different blade, or a supraglottic airway
- Administer a large additional dose of paralytic and wait several minutes
Correct answer: Optimize conditions and limit attempts while maintaining oxygenation, considering an adjunct, a different blade, or a supraglottic airway
When intubation fails but mask ventilation is adequate, the algorithm directs the provider to maintain oxygenation and limit the number of attempts while optimizing conditions, such as repositioning, external laryngeal manipulation, a bougie, a video laryngoscope, or a supraglottic device, rather than repeating identical futile attempts. A cricothyrotomy is reserved for the cannot-ventilate emergency, and more paralytic does not solve a visualization problem.
- A provider records the upper lip bite test class I during the airway examination. What does this result indicate about the patient's mandibular function?
- The lower incisors cannot reach the upper lip at all
- The lower incisors can bite the upper lip but not above the vermilion line
- The patient is edentulous and cannot be assessed
- The lower incisors can bite the upper lip above the vermilion line, indicating good mandibular protrusion
Correct answer: The lower incisors can bite the upper lip above the vermilion line, indicating good mandibular protrusion
An upper lip bite test class I indicates that the lower incisors can advance to bite the upper lip above the vermilion line, reflecting good mandibular protrusion that is reassuring for laryngoscopy. Class II reaches the lip but not above the vermilion line, and class III cannot reach the upper lip at all and predicts difficulty, so class I is the favorable result reflecting preserved jaw mobility.
- A patient with a known difficult airway undergoes inhalational induction while spontaneous ventilation is deliberately preserved. What is the rationale for keeping the patient breathing spontaneously rather than giving a paralytic during this asleep technique?
- It maintains airway patency and gas exchange, so the patient can be allowed to wake if intubation proves impossible
- It speeds the onset of the volatile agent
- It guarantees an excellent laryngoscopic view
- It eliminates the need for airway suction
Correct answer: It maintains airway patency and gas exchange, so the patient can be allowed to wake if intubation proves impossible
Preserving spontaneous ventilation during an inhalational induction in a difficult airway keeps the patient breathing and oxygenating, providing a margin of safety because the anesthetic can be lightened to let the patient wake and resume their own airway if intubation cannot be achieved. Giving a paralytic would commit the provider to securing an airway in an apneic patient, whereas this approach preserves a reversible escape route.
- A provider prepares a rapid sequence induction for a patient who is at high aspiration risk and also has a contraindication to succinylcholine. Which neuromuscular blocker and adjunct combination is the most appropriate alternative to create rapid intubating conditions?
- Standard-dose vecuronium with no reversal plan
- High-dose rocuronium with sugammadex available for rescue reversal
- Cisatracurium at a standard dose
- Pancuronium because of its long duration
Correct answer: High-dose rocuronium with sugammadex available for rescue reversal
When succinylcholine is contraindicated, a high-dose rocuronium technique produces rapid intubating conditions approaching those of succinylcholine, and having sugammadex available allows rapid reversal if a cannot-intubate situation arises. The slower-onset nondepolarizing agents at standard doses do not reliably achieve the speed required for rapid sequence induction, and using a long-acting agent without a reversal strategy compounds the risk in a difficult airway.
- Before a rapid sequence induction, the provider positions the head and applies preoxygenation, then has the patient take several deep breaths of high oxygen. Within a rapid sequence technique, why is thorough preoxygenation especially critical?
- It allows the provider to skip the muscle relaxant entirely
- It neutralizes gastric acid before induction
- Because mask ventilation is classically withheld, the oxygen reserve must sustain the patient through the apneic period until the airway is secured
- It confirms that the endotracheal tube is in the trachea
Correct answer: Because mask ventilation is classically withheld, the oxygen reserve must sustain the patient through the apneic period until the airway is secured
In a classic rapid sequence induction positive-pressure ventilation is avoided to reduce gastric insufflation and aspiration risk, so the patient relies on the oxygen reservoir built by preoxygenation to remain saturated through the apneic interval between induction and intubation. Robust denitrogenation is therefore essential because there is no planned ventilation to replenish oxygen, and it does not replace the relaxant, neutralize acid, or confirm tube position.
- An ASA physical status IV designation is assigned to which patient?
- A patient with mild, well-controlled systemic disease
- A normal, healthy patient
- A moribund patient who is not expected to survive without the operation
- A patient with severe systemic disease that is a constant threat to life
Correct answer: A patient with severe systemic disease that is a constant threat to life
ASA class IV describes a patient with severe systemic disease that is a constant threat to life, such as recent myocardial infarction with ongoing ischemia or severe symptomatic heart failure, sitting above class III's severe but non-life-threatening disease. Class V is reserved for a moribund patient not expected to survive without the operation, so the constant threat to life without imminent demise distinguishes class IV.
- An anesthesia provider notes that the ASA physical status classification, while widely used, was originally designed to describe the patient's preoperative physical condition rather than to predict anesthetic risk directly. What is the most accurate interpretation of an ASA class for perioperative use?
- It is a subjective assessment of physical status that correlates with, but does not by itself determine, perioperative risk
- It precisely quantifies the percentage chance of an anesthetic complication
- It dictates the specific anesthetic technique that must be used
- It replaces the need for a focused history and physical examination
Correct answer: It is a subjective assessment of physical status that correlates with, but does not by itself determine, perioperative risk
The ASA physical status classification is a subjective grading of a patient's overall preoperative physical condition that correlates with perioperative morbidity and mortality but does not by itself precisely quantify risk or prescribe a technique, since surgical and other factors also contribute. It complements rather than replaces a focused history and examination, which is why it is best used as one component of risk stratification.
- A provider uses a simplified risk score that assigns one point each for female sex, nonsmoking status, a history of motion sickness or postoperative nausea and vomiting, and expected postoperative opioid use to predict postoperative nausea and vomiting. What does a higher total score indicate?
- A lower likelihood of postoperative nausea and vomiting
- An increased predicted risk of postoperative nausea and vomiting, justifying more aggressive multimodal prophylaxis
- A contraindication to general anesthesia
- An increased risk of malignant hyperthermia
Correct answer: An increased predicted risk of postoperative nausea and vomiting, justifying more aggressive multimodal prophylaxis
A simplified postoperative nausea and vomiting risk score that counts female sex, nonsmoking status, a history of nausea or motion sickness, and anticipated postoperative opioids stratifies risk, and a higher total predicts a greater chance of nausea and vomiting, prompting the use of combination antiemetic prophylaxis and opioid-sparing strategies. It does not lower risk, contraindicate general anesthesia, or relate to malignant hyperthermia.
- A provider plans antiemetic prophylaxis for a patient at moderate to high risk of postoperative nausea and vomiting and also considers nonpharmacologic and anesthetic strategies. Which anesthetic strategy independently reduces the baseline risk of postoperative nausea and vomiting?
- Maximizing intraoperative opioid administration
- Using nitrous oxide for the entire case
- Using a propofol-based total intravenous technique and minimizing opioids and volatile agents
- Allowing the patient to remain hypovolemic
Correct answer: Using a propofol-based total intravenous technique and minimizing opioids and volatile agents
Substituting a propofol-based total intravenous anesthetic for volatile agents, minimizing perioperative opioids, and ensuring adequate hydration each lower the baseline risk of postoperative nausea and vomiting and complement pharmacologic prophylaxis. Maximizing opioids and using nitrous oxide tend to increase nausea, and hypovolemia worsens it, so the propofol-based opioid-sparing approach is the risk-reducing strategy.
- A provider performs an ankle block for forefoot surgery, anesthetizing five nerves around the ankle. Which nerve, a terminal branch of the femoral nerve, supplies the medial ankle and a strip along the medial foot and must be included for complete coverage?
- The sural nerve
- The deep peroneal nerve
- The posterior tibial nerve
- The saphenous nerve
Correct answer: The saphenous nerve
The ankle block targets five nerves, and of these the saphenous nerve, the terminal sensory branch of the femoral nerve, supplies the medial malleolar region and a strip along the medial aspect of the foot, so it must be blocked for complete coverage. The sural, deep and superficial peroneal, and posterior tibial nerves are branches of the sciatic nerve covering other foot territories, making the saphenous the femoral-derived contributor in this block.
- A provider considers a paravertebral block for analgesia after a unilateral mastectomy. What is the principal characteristic of a thoracic paravertebral block that makes it suitable for this indication?
- It provides predominantly unilateral, segmental somatic and sympathetic analgesia of the chest wall
- It produces a bilateral dense motor and sympathetic block of the trunk
- It anesthetizes the cerebrospinal fluid directly
- It blocks only the lower extremity dermatomes
Correct answer: It provides predominantly unilateral, segmental somatic and sympathetic analgesia of the chest wall
A thoracic paravertebral block deposits local anesthetic where the spinal nerves emerge from the intervertebral foramina, producing predominantly unilateral, segmental somatic and sympathetic analgesia of the chest wall well suited to breast and thoracic surgery with less hypotension than a thoracic epidural. It is not a bilateral neuraxial technique, does not enter the cerebrospinal fluid, and covers thoracic rather than lower-extremity dermatomes.
- A provider adds dexamethasone to the local anesthetic mixture for a peripheral nerve block. What is the primary intended effect of this adjuvant?
- To shorten the onset time only
- To prolong the duration of the block's analgesia
- To provide a marker of intravascular injection
- To produce a denser motor block independent of analgesia
Correct answer: To prolong the duration of the block's analgesia
Dexamethasone added as an adjuvant to a peripheral nerve block prolongs the duration of analgesia, extending the useful life of the block compared with local anesthetic alone. Unlike epinephrine, it is not used as a marker of intravascular injection, and unlike sodium bicarbonate it is not added primarily to speed onset, so its recognized role in regional anesthesia is duration prolongation.
- During a peripheral nerve block using a nerve stimulator technique, the provider observes a motor twitch that persists at a very low stimulating current of 0.2 milliamps. Why should the provider be cautious before injecting under this condition?
- A twitch at low current confirms the safest possible needle position for injection
- Low-current stimulation indicates the needle is in a blood vessel
- A twitch persisting at a very low current suggests the needle tip is intraneural, and injection could cause nerve injury
- The finding has no bearing on the safety of injection
Correct answer: A twitch persisting at a very low current suggests the needle tip is intraneural, and injection could cause nerve injury
A motor response that persists at a very low stimulating current, generally below about 0.2 to 0.3 milliamps, suggests the needle tip is in close or intraneural contact with the nerve, so injecting could deliver local anesthetic within the nerve and cause injury. The provider should withdraw slightly until the twitch is elicited at a higher threshold before injecting, making a persistent low-current twitch a warning rather than a reassuring sign.
- A surgeon requests a regional technique for forearm and hand surgery, and the provider selects an infraclavicular brachial plexus block. At what level of the plexus does this approach deposit local anesthetic?
- At the roots as they emerge between the scalene muscles
- At the trunks above the clavicle
- At the terminal branches in the cubital fossa
- At the cords surrounding the axillary artery below the clavicle
Correct answer: At the cords surrounding the axillary artery below the clavicle
The infraclavicular approach to the brachial plexus targets the cords as they surround the axillary artery deep to the clavicle, providing reliable anesthesia of the arm below the shoulder suitable for forearm and hand surgery. The interscalene approach targets the roots and trunks, the supraclavicular approach addresses the trunks and divisions, and the terminal branches are blocked more distally, so the cords define the infraclavicular level.
- After an interscalene brachial plexus block, the patient develops shortness of breath and ipsilateral diaphragmatic elevation. Which expected side effect of this block explains the finding?
- Phrenic nerve block causing hemidiaphragmatic paresis
- Pneumothorax from pleural puncture
- Local anesthetic systemic toxicity
- A high spinal block
Correct answer: Phrenic nerve block causing hemidiaphragmatic paresis
The interscalene approach almost always spreads to the nearby phrenic nerve, causing ipsilateral hemidiaphragmatic paresis that can produce a sensation of breathlessness, which is usually well tolerated but can be significant in patients with limited respiratory reserve. This expected phrenic effect is distinct from a pneumothorax, systemic toxicity, or a high spinal, and it is a key reason to weigh the interscalene block carefully in patients with severe pulmonary disease.
- A provider is asked the most reliable single confirmation that an endotracheal tube has been correctly placed in the trachea immediately after intubation. Which finding provides this confirmation?
- Bilateral breath sounds on auscultation alone
- Sustained end-tidal carbon dioxide detected over several breaths
- Misting of the tube with each breath
- Visible chest rise with ventilation
Correct answer: Sustained end-tidal carbon dioxide detected over several breaths
Sustained detection of exhaled carbon dioxide over several consecutive breaths is the most reliable confirmation of tracheal tube placement, because persistent capnographic waveforms occur only when ventilation reaches the lungs rather than the esophagus. Auscultation, tube misting, and chest rise are supportive but can be misleading, which is why continuous capnography is the standard confirmation immediately after intubation.
- A provider plans general anesthesia for a patient and reviews the standard requirement that a qualified anesthesia provider remain present throughout the conduct of every general anesthetic. What is the principal reason for this continuous-presence standard?
- To document the procedure for billing
- To operate the surgical equipment
- To allow uninterrupted vigilance so rapid changes in the patient's condition are detected and treated immediately
- To reduce the number of monitors needed
Correct answer: To allow uninterrupted vigilance so rapid changes in the patient's condition are detected and treated immediately
The standard that a qualified anesthesia provider be continuously present during a general anesthetic exists because a patient's condition can change abruptly and dangerously, and immediate human vigilance is required to recognize and respond to such changes promptly. Continuous presence supports patient safety rather than billing, equipment operation, or reducing monitoring, reflecting the irreplaceable role of the attentive clinician.
- A provider performs a preoperative assessment on a patient with an opioid use disorder maintained on buprenorphine. Why is this medication history important for perioperative pain planning?
- Buprenorphine has no effect on perioperative analgesia
- It guarantees that the patient will need no analgesia
- It must always be stopped abruptly before any surgery
- Its high opioid receptor affinity can blunt the effect of additional full opioid agonists, complicating acute pain control and requiring a deliberate multimodal plan
Correct answer: Its high opioid receptor affinity can blunt the effect of additional full opioid agonists, complicating acute pain control and requiring a deliberate multimodal plan
Buprenorphine binds opioid receptors with high affinity and partial agonist activity, so it can blunt the analgesic effect of additional full agonists and complicate acute postoperative pain control, making an individualized multimodal plan, regional techniques, and coordinated decisions about continuing the agent important. The history is highly relevant rather than negligible, does not eliminate analgesic needs, and abrupt discontinuation is not a universal requirement.
- A provider caring for a chronic opioid-tolerant patient after major surgery finds that standard opioid doses provide inadequate analgesia. Which general principle best guides management of this patient?
- Provide the patient's baseline opioid requirement plus additional analgesia for the acute surgical pain, emphasizing multimodal and regional techniques
- Withhold opioids entirely because the patient is tolerant
- Use only the standard opioid-naive dosing
- Reverse all opioids with naloxone preoperatively
Correct answer: Provide the patient's baseline opioid requirement plus additional analgesia for the acute surgical pain, emphasizing multimodal and regional techniques
An opioid-tolerant patient must receive their usual baseline opioid requirement to avoid withdrawal plus additional analgesia to treat the acute surgical pain, with strong reliance on multimodal nonopioid agents and regional techniques to manage their typically higher needs. Withholding opioids, applying opioid-naive dosing, or reversing baseline opioids would precipitate withdrawal or undertreatment, so accounting for tolerance is the guiding principle.
- A provider plans a Bier block and asks why a double-cuff (dual-tourniquet) system is commonly used for intravenous regional anesthesia. What advantage does the double cuff provide?
- It doubles the dose of local anesthetic that can be used
- It allows the distal cuff over already-anesthetized skin to be inflated and the proximal cuff deflated, reducing tourniquet pain during longer procedures
- It eliminates the need to exsanguinate the limb
- It permits the tourniquet to be released immediately after injection
Correct answer: It allows the distal cuff over already-anesthetized skin to be inflated and the proximal cuff deflated, reducing tourniquet pain during longer procedures
A double-cuff system manages tourniquet pain by first inflating the proximal cuff, and once the limb is anesthetized inflating the distal cuff over now-numb skin and deflating the proximal cuff, so the constricting pressure sits over anesthetized tissue. It does not increase the safe local anesthetic dose, replace exsanguination, or permit early release, which remains hazardous because of systemic toxicity risk.
- A provider managing local anesthetic systemic toxicity prepares to give the lipid emulsion rescue. Within current guidance, what is the recommended initial approach to lipid emulsion administration?
- A single small dose with no further administration
- Administering it only after the patient has fully recovered
- An initial bolus followed by a continuous infusion, with the bolus repeatable for persistent cardiovascular collapse
- Giving it by intramuscular injection
Correct answer: An initial bolus followed by a continuous infusion, with the bolus repeatable for persistent cardiovascular collapse
Lipid emulsion therapy for severe local anesthetic systemic toxicity is given as an intravenous bolus followed by a continuous infusion, with the bolus repeatable and the infusion rate increased if cardiovascular instability persists, alongside high-quality resuscitation. It is administered intravenously and during the crisis rather than after recovery, and a single small dose would be inadequate for ongoing collapse.
- A provider compares local anesthetics and notes that bupivacaine carries a higher risk of cardiac arrest from local anesthetic systemic toxicity than lidocaine at equipotent regional doses. Which property of bupivacaine explains this greater cardiotoxicity?
- Its faster onset of action
- Its lower lipid solubility
- Its shorter duration of action
- Its avid, slow-to-dissociate binding to cardiac sodium channels
Correct answer: Its avid, slow-to-dissociate binding to cardiac sodium channels
Bupivacaine binds cardiac sodium channels avidly and dissociates slowly, so it accumulates in the conduction system and produces refractory arrhythmias and cardiac arrest more readily than lidocaine, which binds and releases quickly. This fast-in, slow-out binding underlies its disproportionate cardiotoxicity and is why severe bupivacaine toxicity may require prolonged resuscitation and lipid emulsion rather than relating to onset, duration, or low lipid solubility.
- A provider implements an enhanced recovery after surgery pathway for major colorectal surgery. Which pathway element directly aims to reduce postoperative ileus and is considered a core component?
- Opioid-sparing multimodal analgesia combined with early oral intake and early mobilization
- Prolonged routine nasogastric tube decompression
- Strict bed rest for several days
- Routine prolonged fasting after surgery
Correct answer: Opioid-sparing multimodal analgesia combined with early oral intake and early mobilization
Reducing postoperative ileus in enhanced recovery pathways relies on minimizing opioids through multimodal analgesia, resuming oral intake early, and mobilizing the patient promptly, since opioids, immobility, and prolonged fasting all slow return of bowel function. Routine prolonged nasogastric decompression, bed rest, and extended postoperative fasting run counter to these principles and are generally avoided.
- A provider explains that an enhanced recovery after surgery program is built on the concept of attenuating the surgical stress response. Why does reducing the perioperative stress response improve recovery?
- It increases insulin resistance to spare glucose
- It blunts catabolic, inflammatory, and neuroendocrine responses that contribute to complications and delayed recovery
- It guarantees the absence of any postoperative pain
- It removes the need for postoperative monitoring
Correct answer: It blunts catabolic, inflammatory, and neuroendocrine responses that contribute to complications and delayed recovery
Enhanced recovery pathways aim to attenuate the surgical stress response, the catabolic, inflammatory, and neuroendocrine cascade triggered by surgery, because this response drives insulin resistance, fluid retention, immune suppression, and organ dysfunction that prolong recovery. Bundled measures such as carbohydrate loading, regional analgesia, normothermia, and goal-directed fluids reduce this response, which improves outcomes rather than eliminating pain or monitoring.
- A provider performs an ultrasound-guided transversus abdominis plane block. Which nerves provide the somatic abdominal wall analgesia that this block targets?
- The sacral plexus nerves
- The phrenic nerve
- The thoracolumbar nerves (anterior rami of roughly T7 through L1) traveling in the plane
- The lumbar sympathetic chain
Correct answer: The thoracolumbar nerves (anterior rami of roughly T7 through L1) traveling in the plane
The transversus abdominis plane block anesthetizes the anterior rami of the lower thoracic and first lumbar nerves, approximately T7 through L1, which course in the fascial plane between the internal oblique and transversus abdominis to supply the anterior abdominal wall. It does not target the sacral plexus, phrenic nerve, or sympathetic chain, which is why it relieves somatic incisional pain of the abdominal wall.
- A massive transfusion protocol is activated for an exsanguinating trauma patient. Which transfusion ratio strategy is the modern recommended approach during the initial resuscitation before laboratory results are available?
- Red cells alone until laboratory values return
- Crystalloid resuscitation alone to avoid product use
- Platelets alone followed later by red cells
- A balanced ratio approximating equal units of red cells, plasma, and platelets
Correct answer: A balanced ratio approximating equal units of red cells, plasma, and platelets
During the empiric phase of massive transfusion before laboratory guidance is available, current practice favors a balanced ratio approximating equal units of packed red cells, plasma, and platelets to recreate something close to whole blood and prevent dilutional coagulopathy. Giving red cells or crystalloid alone neglects clotting factors and platelets, worsening coagulopathy, so balanced component delivery anchors early hemostatic resuscitation.
- A trauma patient receiving a large volume of older stored packed red cells is at risk for hyperkalemia. Why can rapid massive transfusion of stored blood cause an elevated serum potassium?
- Stored red cells leak potassium into the supernatant over time, and rapid infusion delivers this potassium load faster than it can be redistributed
- Citrate releases potassium into the plasma
- Transfused plasma is rich in potassium chloride
- Cold blood stimulates potassium production by the kidneys
Correct answer: Stored red cells leak potassium into the supernatant over time, and rapid infusion delivers this potassium load faster than it can be redistributed
During storage, red cells gradually leak intracellular potassium into the surrounding plasma, so rapidly transfusing a large volume of older units delivers this accumulated potassium faster than the body can buffer or redistribute it, risking hyperkalemia and cardiac effects. This mechanism differs from citrate's effect on calcium, and using fresher or washed units and slowing the rate when feasible help mitigate the risk.
- A bleeding patient's thromboelastography tracing shows a normal R time and maximum amplitude but a markedly increased clot lysis at 30 minutes. Which therapy most directly addresses this abnormality?
- Platelet transfusion
- An antifibrinolytic agent such as tranexamic acid
- Fresh frozen plasma
- Cryoprecipitate
Correct answer: An antifibrinolytic agent such as tranexamic acid
An increased percent lysis on thromboelastography indicates hyperfibrinolysis, in which formed clot is broken down prematurely, and the targeted treatment is an antifibrinolytic such as tranexamic acid that inhibits plasmin-mediated clot breakdown. A normal R time and maximum amplitude indicate adequate initiation and clot strength, so plasma, platelets, and cryoprecipitate would not correct the excessive lysis identified by the test.
- A provider explains how the alpha angle on a thromboelastogram is interpreted during bleeding management. What does the alpha angle primarily reflect?
- The time to initial clot formation governed by clotting factors
- The maximum clot strength from platelets
- The rate of clot strengthening, largely dependent on fibrinogen
- The degree of clot breakdown over time
Correct answer: The rate of clot strengthening, largely dependent on fibrinogen
The alpha angle on a thromboelastogram measures the rate at which the clot builds strength and is largely determined by fibrinogen and, to a lesser degree, platelets, so a decreased alpha angle suggests inadequate fibrinogen that may be corrected with cryoprecipitate or fibrinogen concentrate. The R time reflects clot initiation, the maximum amplitude reflects ultimate strength, and the lysis parameter reflects breakdown, distinguishing each component.
- A provider plans deliberate controlled hypotension for a major head and neck procedure to reduce blood loss. What is the underlying physiologic rationale for how lowering the mean arterial pressure decreases surgical bleeding?
- It increases blood viscosity to slow flow
- It causes generalized vasoconstriction of the surgical site only
- It increases platelet aggregation systemically
- Reducing the perfusion pressure to the surgical field lessens the volume and rate of bleeding from cut vessels
Correct answer: Reducing the perfusion pressure to the surgical field lessens the volume and rate of bleeding from cut vessels
Deliberate controlled hypotension reduces surgical bleeding because lowering the arterial pressure decreases the driving perfusion pressure to the surgical field, so blood escapes from divided vessels more slowly and in smaller volume, improving the operative view. The benefit comes from reduced perfusion pressure rather than altered viscosity, localized vasoconstriction, or enhanced platelet function, and it must be balanced against the risk of organ ischemia.
- A frightened toddler requires general anesthesia and the provider plans an inhalational induction. Which preinduction strategy is commonly used to reduce separation anxiety and facilitate a smooth mask induction in young children?
- Oral midazolam premedication or allowing parental presence at induction
- Administering a long-acting muscle relaxant orally
- Performing a rapid sequence induction by default
- Withholding all premedication to speed recovery
Correct answer: Oral midazolam premedication or allowing parental presence at induction
Reducing a young child's separation anxiety before an inhalational induction commonly involves anxiolytic premedication such as oral midazolam or permitting a parent to be present at induction, both of which ease cooperation and a smooth mask induction. An oral muscle relaxant is not used for this purpose, rapid sequence induction is reserved for specific indications, and withholding anxiolysis would not address the distress driving a turbulent induction.
- A provider selects ketamine for induction in a patient with active bronchospastic disease and hemodynamic instability. Which property makes ketamine well suited to this situation?
- It produces profound vasodilation and hypotension
- It tends to support blood pressure through sympathetic stimulation and has bronchodilating properties
- It reliably abolishes airway reflexes immediately
- It causes significant respiratory depression at induction doses
Correct answer: It tends to support blood pressure through sympathetic stimulation and has bronchodilating properties
Ketamine indirectly stimulates the sympathetic nervous system, which tends to maintain or raise blood pressure and heart rate, and it produces bronchodilation, making it advantageous for induction in a hemodynamically unstable patient with active bronchospasm. It preserves respiratory drive and airway reflexes relatively well rather than abolishing them, distinguishing it from agents that cause vasodilation, hypotension, or marked respiratory depression.
- A provider chooses an epidural rather than a single-shot spinal for a procedure expected to last many hours with a need for postoperative analgesia. What feature of the epidural technique makes it advantageous here?
- It produces a faster, denser onset than a spinal
- It carries no risk of dural puncture
- An indwelling catheter allows the block to be titrated and extended for prolonged surgery and postoperative analgesia
- It always avoids hypotension
Correct answer: An indwelling catheter allows the block to be titrated and extended for prolonged surgery and postoperative analgesia
An epidural technique places a catheter that can be redosed or infused, allowing the block to be titrated to the surgical level and extended for a long operation and into the postoperative period for analgesia, which a single-shot spinal cannot match. A spinal actually has a faster, denser onset, the epidural still carries some risk of inadvertent dural puncture, and sympathetic blockade can still cause hypotension.
- A provider identifies the epidural space during placement using the loss-of-resistance technique. What anatomic event produces the loss of resistance that signals correct needle tip position?
- The needle entering the subarachnoid space and contacting cerebrospinal fluid
- The needle striking the vertebral lamina
- The needle entering an epidural vein
- The needle tip passing through the ligamentum flavum into the potential epidural space
Correct answer: The needle tip passing through the ligamentum flavum into the potential epidural space
The loss-of-resistance technique relies on the dense ligamentum flavum offering firm resistance to a syringe of air or saline, and the sudden loss of that resistance occurs as the needle tip pops through the ligamentum flavum into the epidural space. Reaching the subarachnoid space would yield cerebrospinal fluid, striking the lamina gives bony resistance, and entering an epidural vein gives blood, so the ligamentum flavum is the structure whose penetration defines the endpoint.
- A provider injects a hyperbaric spinal anesthetic with the patient sitting and keeps the patient upright for several minutes to produce a saddle block for perianal surgery. Which principle of spinal anesthesia does this maneuver use?
- A hyperbaric solution settles caudally to the sacral segments under gravity in the seated patient, limiting the block to the perineum
- Hypobaric solutions sink in the sitting position
- Baricity is irrelevant to a saddle block
- The sitting position raises the block to the high thoracic level
Correct answer: A hyperbaric solution settles caudally to the sacral segments under gravity in the seated patient, limiting the block to the perineum
A saddle block exploits baricity by injecting a hyperbaric, heavier-than-cerebrospinal-fluid solution with the patient seated and keeping them upright, so the local anesthetic settles caudally onto the sacral nerve roots that supply the perineum, producing a limited low block. A hyperbaric solution sinks rather than rises, and maintaining the sitting position confines rather than elevates the block, which is why position and baricity together control its distribution.
- A provider weighs general versus regional anesthesia for a patient with severe symptomatic aortic stenosis undergoing a lower-extremity procedure. Why is a sudden, dense neuraxial sympathectomy a particular concern in this patient?
- Aortic stenosis makes the patient tolerate vasodilation especially well
- The fixed obstruction limits the heart's ability to compensate for the abrupt drop in afterload and preload, risking dangerous hypotension
- Neuraxial anesthesia is always absolutely contraindicated in valvular disease
- The block would directly worsen the valve gradient
Correct answer: The fixed obstruction limits the heart's ability to compensate for the abrupt drop in afterload and preload, risking dangerous hypotension
In severe aortic stenosis the fixed valvular obstruction limits the ability to increase cardiac output, so the abrupt vasodilation and reduced preload of a dense single-shot spinal sympathectomy can cause profound, poorly tolerated hypotension and coronary hypoperfusion. This favors a carefully titrated technique, such as a slowly dosed epidural or general anesthesia with vigilant hemodynamic control, rather than an absolute prohibition, since the concern is the rapidity and depth of the sympathectomy.
- A provider must select an anesthetic for an emergency cesarean delivery for fetal bradycardia when no epidural is in place and time is critical. Which technique is generally fastest to establish surgical anesthesia in this urgent setting, accepting its trade-offs?
- A slowly titrated epidural
- A peripheral nerve block
- General anesthesia with a rapid sequence induction
- Local infiltration by the surgeon alone
Correct answer: General anesthesia with a rapid sequence induction
When a true emergency cesarean is required and no functioning neuraxial catheter is present, general anesthesia with a rapid sequence induction provides the fastest reliable surgical anesthesia, accepting the trade-offs of aspiration and airway risk in the parturient. A slowly titrated epidural is too slow, peripheral blocks and local infiltration alone cannot provide adequate abdominal surgical anesthesia, so speed favors a rapid sequence general technique in this scenario.
- A provider notes that a patient has a documented plasma cholinesterase (pseudocholinesterase) deficiency. How does this affect anesthetic planning regarding succinylcholine?
- It has no effect on succinylcholine duration
- Succinylcholine becomes completely ineffective
- It mandates a higher dose of succinylcholine
- Succinylcholine metabolism is markedly prolonged, causing extended paralysis that requires continued ventilation until recovery
Correct answer: Succinylcholine metabolism is markedly prolonged, causing extended paralysis that requires continued ventilation until recovery
Plasma cholinesterase normally hydrolyzes succinylcholine quickly, so a deficiency markedly prolongs its action and can cause hours of paralysis, requiring continued sedation and mechanical ventilation until neuromuscular function recovers spontaneously. The drug still works rather than failing, a higher dose would worsen the problem, and recognizing the deficiency, often from family history, allows the provider to avoid or anticipate the prolonged block.
- A provider performs a focused preoperative evaluation and assesses the patient's functional capacity in metabolic equivalents. Approximately what level of activity corresponds to four metabolic equivalents, a commonly used threshold of adequate functional capacity?
- Climbing a flight of stairs or walking up a hill
- Lying in bed without exertion
- Running a competitive marathon
- Eating and dressing only
Correct answer: Climbing a flight of stairs or walking up a hill
Roughly four metabolic equivalents corresponds to activities such as climbing a flight of stairs, walking up a hill, or walking briskly on level ground, and the ability to perform this level without cardiac symptoms is a commonly cited threshold of adequate functional capacity in preoperative evaluation. Resting in bed or only performing self-care reflects very low capacity, whereas running a marathon reflects a much higher level than this threshold.
- A provider applies aspiration precautions for a patient with an unknown last oral intake presenting for urgent surgery. Which combination of factors most increases this patient's aspiration risk and supports treating the stomach as full?
- A long fasting interval and no gastrointestinal pathology
- Recent oral intake, pain, opioids, trauma, or bowel obstruction that delay gastric emptying
- Elective scheduling after appropriate fasting
- A history of easy intubation
Correct answer: Recent oral intake, pain, opioids, trauma, or bowel obstruction that delay gastric emptying
Aspiration risk rises with factors that increase gastric volume or impair emptying and protective reflexes, such as recent intake, acute pain, opioid administration, trauma, pregnancy, diabetes, and bowel obstruction, and an unknown intake history in an urgent case warrants treating the stomach as full. A long fast without pathology or appropriate elective fasting lowers risk, and a history of easy intubation does not reduce aspiration risk, so the delaying factors define the precautionary approach.
- A provider monitors a patient under monitored anesthesia care and recognizes that the patient has unintentionally progressed from moderate to deep sedation. Which clinical finding most clearly signals this deeper plane?
- Purposeful response to verbal commands
- Fully awake conversation
- The patient responds only to repeated or painful stimulation and may require airway support
- Normal spontaneous ventilation with brisk verbal responses
Correct answer: The patient responds only to repeated or painful stimulation and may require airway support
Deep sedation is characterized by a patient who can be aroused only by repeated or painful stimulation rather than verbal commands, with possible impairment of spontaneous ventilation and airway patency, signaling progression beyond moderate sedation. Purposeful responses to verbal commands and intact conversation indicate lighter levels, so the loss of response to voice and the need for airway vigilance mark the transition to deep sedation.
- A provider performs a Bier block and recognizes that intravenous regional anesthesia is best suited to which type of procedure?
- Prolonged operations lasting several hours
- Major intra-abdominal surgery
- Procedures requiring postoperative continuous analgesia
- Short procedures on the distal extremity, generally under about an hour
Correct answer: Short procedures on the distal extremity, generally under about an hour
Intravenous regional anesthesia is best suited to short procedures on the distal upper or lower extremity, generally under about an hour, because tourniquet pain and the safe limit of tourniquet time constrain its duration and it provides no lasting postoperative analgesia once the cuff is released. It is unsuitable for prolonged operations, intra-abdominal surgery, or cases needing continuous postoperative analgesia, which call for other techniques.
- A provider plans intraoperative goal-directed fluid therapy and uses a passive leg raise to assess fluid responsiveness. How does this maneuver predict whether a fluid bolus will increase cardiac output?
- It transiently autotransfuses venous blood toward the heart, and a resulting rise in stroke volume suggests the patient is fluid responsive
- It permanently shifts fluid out of the legs
- It directly measures the blood pressure in the legs
- It assesses peripheral nerve function
Correct answer: It transiently autotransfuses venous blood toward the heart, and a resulting rise in stroke volume suggests the patient is fluid responsive
A passive leg raise temporarily shifts venous blood from the lower extremities toward the central circulation, mimicking a reversible fluid challenge, and an increase in stroke volume or cardiac output in response predicts that the patient will benefit from a fluid bolus. This dynamic, reversible test of preload responsiveness guides goal-directed therapy and does not permanently move fluid, measure leg pressure, or assess nerves.
- A provider integrates multimodal analgesia for a patient undergoing major surgery and chooses acetaminophen as a foundational component. Why is acetaminophen a useful base agent in a multimodal plan?
- It provides profound analgesia sufficient to avoid all other agents
- It contributes opioid-sparing analgesia with a favorable safety profile when dosed within limits, complementing other agents
- It acts as a neuromuscular blocker
- It reliably eliminates neuropathic pain on its own
Correct answer: It contributes opioid-sparing analgesia with a favorable safety profile when dosed within limits, complementing other agents
Acetaminophen is a useful foundation of multimodal analgesia because it provides modest analgesia and an opioid-sparing effect with a generally favorable safety profile when kept within recommended dose limits, layering with nonsteroidal agents, regional techniques, and opioids. It is not potent enough to replace all other analgesics, has no neuromuscular or specific neuropathic action, so its value is as a safe, complementary base agent.
- A provider managing a regional anesthesia program emphasizes that, even with ultrasound guidance, no single safety measure eliminates the risk of local anesthetic systemic toxicity. Which combination best reflects a layered prevention strategy?
- Using the maximum dose for every block to ensure success
- Injecting the full dose rapidly to shorten the procedure
- Calculating a weight-based maximum dose, aspirating before injection, dosing incrementally, and monitoring the patient
- Avoiding aspiration to keep the needle still
Correct answer: Calculating a weight-based maximum dose, aspirating before injection, dosing incrementally, and monitoring the patient
Preventing local anesthetic systemic toxicity relies on a layered approach: calculating and respecting a weight-based maximum dose, aspirating before injection to detect intravascular placement, injecting in small incremental aliquots while observing for early symptoms, and continuously monitoring the patient. Using maximum doses routinely, rapid full-dose injection, or skipping aspiration each remove a safety layer and increase the risk, so the combined practices define safe technique.
- A provider reviews the indications for a peripheral nerve block versus a neuraxial technique for a patient on therapeutic anticoagulation who needs analgesia for a distal lower-limb procedure. Why might a superficial, compressible peripheral nerve block be considered relatively safer than a neuraxial block in this patient?
- Peripheral blocks never cause bleeding
- Anticoagulation does not affect peripheral blocks at all
- Peripheral blocks require no anatomic knowledge
- Bleeding at a superficial, compressible site is more accessible and lacks the enclosed neuraxial space where a hematoma can compress the spinal cord
Correct answer: Bleeding at a superficial, compressible site is more accessible and lacks the enclosed neuraxial space where a hematoma can compress the spinal cord
A superficial, compressible peripheral nerve block is generally considered to carry a lower catastrophic-bleeding risk than a neuraxial block in an anticoagulated patient because a hematoma at an accessible site can be detected and compressed, whereas bleeding in the confined neuraxial space can compress the spinal cord and cause permanent injury. This does not mean peripheral blocks never bleed or that anticoagulation is irrelevant, so site selection and individualized risk assessment still apply.
- A provider plans a continuous epidural infusion for postoperative analgesia and combines a dilute local anesthetic with an opioid. What is the rationale for combining these two drug classes in the epidural infusion?
- Their synergy allows lower concentrations of each, providing effective analgesia while limiting motor block and individual side effects
- To produce a dense motor block for ambulation
- The opioid blocks sodium channels like the local anesthetic
- To shorten the duration of analgesia
Correct answer: Their synergy allows lower concentrations of each, providing effective analgesia while limiting motor block and individual side effects
Combining a dilute local anesthetic with an opioid in an epidural infusion exploits their synergy at the spinal cord, so lower concentrations of each provide effective analgesia while minimizing the dense motor block of higher local anesthetic concentrations and the side effects of higher opioid doses. The opioid acts on dorsal horn opioid receptors rather than sodium channels, and the combination aims to optimize analgesia with preserved mobility rather than to shorten it.
- A provider counsels a patient that any anesthetic technique carries inherent risks and that the decision involves weighing risks against benefits. Which ethical principle is reflected when the provider also weighs the obligation to act in the patient's best interest against the obligation to avoid harm?
- Justice and confidentiality
- Beneficence balanced against nonmaleficence
- Autonomy alone
- Fidelity and veracity only
Correct answer: Beneficence balanced against nonmaleficence
Weighing the duty to act in the patient's best interest against the duty to avoid causing harm reflects balancing beneficence and nonmaleficence, two core ethical principles that underlie the risk-benefit reasoning of anesthetic planning. Autonomy concerns the patient's right to choose, justice concerns fair allocation, and fidelity and veracity address loyalty and truthfulness, so the benefit-versus-harm balance specifically engages beneficence and nonmaleficence.
- A provider plans a regional technique for postoperative analgesia and explains the concept of preemptive or preventive analgesia. What does this concept describe?
- Withholding analgesia until the patient reports severe pain
- Using only a single dose of opioid at the end of surgery
- Administering analgesic interventions before and throughout the period of noxious stimulation to reduce central sensitization and subsequent pain
- Treating only the psychological component of pain
Correct answer: Administering analgesic interventions before and throughout the period of noxious stimulation to reduce central sensitization and subsequent pain
Preemptive or preventive analgesia describes delivering analgesic interventions, such as regional blocks and multimodal agents, before and throughout the noxious surgical stimulus to blunt the development of central sensitization and reduce postoperative pain and analgesic requirements. Waiting for severe pain, relying on a single late opioid dose, or addressing only psychological factors does not capture this proactive, mechanism-based strategy.
- A provider reviews the standard for documenting a preanesthetic evaluation before an elective anesthetic. Which elements are essential components of this assessment?
- The surgeon's preferred postoperative diet only
- The hospital billing codes for the case
- A list of the operating room staff present
- A focused history, airway and physical examination, review of relevant studies, and an anesthetic plan with risk discussion
Correct answer: A focused history, airway and physical examination, review of relevant studies, and an anesthetic plan with risk discussion
A complete preanesthetic evaluation includes a focused history including comorbidities, medications, allergies, and prior anesthetic experiences, an airway and pertinent physical examination, review of relevant laboratory and diagnostic studies, assignment of physical status, and formulation of an anesthetic plan discussed with the patient. Billing codes, staffing lists, and dietary preferences are not the substantive clinical components of this safety-focused assessment.
- A provider administers a spinal anesthetic and chooses to add a small dose of an opioid to the local anesthetic to improve intraoperative and early postoperative analgesia. Which monitoring consideration follows from adding a hydrophilic neuraxial opioid such as morphine?
- Extended monitoring for delayed respiratory depression is warranted because of rostral cerebrospinal fluid spread
- No additional monitoring is needed
- The patient requires immediate reversal with naloxone
- Monitoring is needed only for the duration of the surgery
Correct answer: Extended monitoring for delayed respiratory depression is warranted because of rostral cerebrospinal fluid spread
Adding a hydrophilic neuraxial opioid such as morphine to a spinal anesthetic warrants extended postoperative respiratory monitoring because the drug can spread rostrally in the cerebrospinal fluid to the brainstem and cause delayed respiratory depression hours after administration. Routine reversal is not indicated absent toxicity, and confining monitoring to the operative period would miss the characteristic delayed risk, so prolonged surveillance is the appropriate response.
- A provider weighs a peripheral nerve block against general anesthesia alone for an ambulatory shoulder arthroscopy and incorporates the block into the plan. Which general benefit supports adding a regional block in an ambulatory setting?
- It lengthens the recovery room stay
- It provides targeted analgesia that reduces opioid requirements, postoperative nausea, and time to discharge readiness
- It eliminates the need for any general anesthesia in every case
- It guarantees zero postoperative pain after the block resolves
Correct answer: It provides targeted analgesia that reduces opioid requirements, postoperative nausea, and time to discharge readiness
Incorporating a peripheral nerve block in ambulatory surgery provides focused, effective analgesia that lowers opioid requirements and associated nausea and sedation, often shortening the time to meet discharge criteria and supporting same-day discharge. It does not lengthen recovery, is frequently combined with light general anesthesia or sedation rather than replacing it universally, and rebound pain can occur as the block resolves, so a multimodal plan is still needed.
- A provider documents that the patient's stomach should be considered full and selects a cuffed endotracheal tube with a rapid sequence induction. Within general anesthesia, what is the primary protective function of the inflated endotracheal tube cuff in this context?
- It measures airway pressure
- It warms the inspired gas
- It seals the trachea to reduce the passage of regurgitated gastric contents into the lungs and prevents gas leak
- It directly suctions the stomach
Correct answer: It seals the trachea to reduce the passage of regurgitated gastric contents into the lungs and prevents gas leak
An inflated endotracheal tube cuff seals the trachea so that positive-pressure ventilation does not leak around the tube and, importantly in an aspiration-risk patient, helps prevent regurgitated gastric contents from passing into the lower airway. The cuff does not measure pressure, warm gas, or suction the stomach, so its protective role in a full-stomach rapid sequence induction is the tracheal seal.
- A provider performs a regional anesthetic and emphasizes the importance of the time-out and confirming laterality before a peripheral nerve block. Why is confirming the correct side particularly important before a nerve block?
- Local anesthetic on the wrong side is harmless
- Side confirmation is needed only for spinal anesthesia
- The block side does not affect surgical anesthesia
- A wrong-side block is a preventable never event that fails to anesthetize the surgical site and exposes the patient to an unnecessary, potentially harmful procedure
Correct answer: A wrong-side block is a preventable never event that fails to anesthetize the surgical site and exposes the patient to an unnecessary, potentially harmful procedure
Confirming laterality with a time-out before a peripheral nerve block prevents a wrong-side block, a recognized never event that leaves the operative limb unanesthetized while subjecting the patient to an unnecessary block with its attendant risks such as nerve injury and local anesthetic exposure. A wrong-side block is not harmless or irrelevant, and side verification applies to peripheral blocks as well as neuraxial procedures, so the safety check is essential.
- A provider chooses a supraclavicular brachial plexus block for upper-limb surgery and is aware of a characteristic complication of this approach due to the proximity of the lung apex. Which complication must the provider specifically watch for?
- Pneumothorax
- Cauda equina syndrome
- Post-dural puncture headache
- Malignant hyperthermia
Correct answer: Pneumothorax
The supraclavicular approach to the brachial plexus places the needle near the dome of the pleura, so pneumothorax is a recognized complication that the provider must anticipate and monitor for, particularly with worsening respiratory symptoms after the block. Cauda equina syndrome and post-dural puncture headache are neuraxial complications, and malignant hyperthermia is unrelated, so the apical lung proximity makes pneumothorax the characteristic risk of this block.
- A provider plans deliberate controlled hypotension and selects the technique only after confirming that the patient is normovolemic and has no significant end-organ disease. During the technique, which monitor is most important for detecting inadequate perfusion early?
- A peripheral nerve stimulator
- Continuous, ideally invasive, beat-to-beat arterial blood pressure monitoring with attention to organ-specific signs
- A urinary catheter checked once at the end of the case
- A single baseline temperature reading
Correct answer: Continuous, ideally invasive, beat-to-beat arterial blood pressure monitoring with attention to organ-specific signs
Because deliberate controlled hypotension narrows the margin between adequate and inadequate organ perfusion, continuous beat-to-beat blood pressure monitoring, often with an arterial line, together with attention to organ-specific indicators such as electrocardiographic ischemia and urine output, is essential to detect underperfusion early and restore pressure. A nerve stimulator assesses neuromuscular function, and a single end-of-case urine check or baseline temperature cannot provide the real-time perfusion surveillance the technique demands.
- While weaning a patient from cardiopulmonary bypass after valve replacement, the heart fills but ejects poorly and the blood pressure remains low despite adequate volume. Which intervention is most appropriate to support separation from bypass?
- Reversing anticoagulation immediately with protamine before the heart is supported
- Deepening the volatile anesthetic to relax the heart
- Re-administering a full heparinizing dose to improve circuit flow
- Starting an inotrope such as epinephrine or milrinone to augment myocardial contractility
Correct answer: Starting an inotrope such as epinephrine or milrinone to augment myocardial contractility
Poor ejection with a full heart during separation from cardiopulmonary bypass indicates the failing ventricle needs contractile support, so an inotrope such as epinephrine or milrinone is titrated to improve cardiac output before and after coming off the circuit. More heparin and deeper volatile agent would not help a stunned ventricle, and protamine is withheld until the heart is reliably supporting the circulation off bypass.
- A patient undergoing coronary artery bypass grafting on cardiopulmonary bypass is given an antifibrinolytic agent. What is the primary goal of administering tranexamic acid in this cardiac surgical setting?
- To lower systemic vascular resistance during rewarming
- To anticoagulate the bypass circuit in place of heparin
- To provide myocardial protection during aortic cross-clamping
- To reduce perioperative bleeding and the need for blood transfusion by inhibiting clot breakdown
Correct answer: To reduce perioperative bleeding and the need for blood transfusion by inhibiting clot breakdown
Tranexamic acid is an antifibrinolytic that blocks plasmin-mediated clot breakdown, reducing perioperative bleeding and transfusion requirements during cardiac surgery where bypass activates fibrinolysis. It does not anticoagulate the circuit, which is the role of heparin, and it provides neither myocardial protection nor vasodilation during rewarming.
- An elderly patient with severe aortic stenosis undergoes transcatheter aortic valve replacement in the hybrid suite. During rapid ventricular pacing for balloon valvuloplasty, what hemodynamic effect should the anesthesia provider expect and prepare to manage?
- A sustained hypertensive surge requiring vasodilators
- A transient profound drop in cardiac output and blood pressure during the pacing run
- No change because pacing does not affect output during the procedure
- An immediate rise in cardiac output from improved coronary flow
Correct answer: A transient profound drop in cardiac output and blood pressure during the pacing run
Rapid ventricular pacing during transcatheter aortic valve replacement deliberately reduces stroke volume so the balloon and valve can be deployed without dislodgement, producing a brief but profound fall in cardiac output and blood pressure that the provider anticipates and supports. It does not cause hypertension or improved output, and the hemodynamic effect is real and significant, requiring readiness with vasopressors.
- A patient is undergoing transcatheter aortic valve replacement via a transfemoral approach under monitored anesthesia care with sedation. Which advantage most supports choosing conscious sedation over general anesthesia for a suitable candidate?
- It permits faster recovery and may shorten length of stay while allowing neurologic assessment
- It removes the possibility of vascular complications
- It guarantees the procedure can be completed without conversion to general anesthesia
- It eliminates any need for invasive arterial monitoring
Correct answer: It permits faster recovery and may shorten length of stay while allowing neurologic assessment
Monitored anesthesia care for transfemoral transcatheter aortic valve replacement can speed recovery, facilitate ongoing neurologic assessment, and shorten hospital stay in appropriately selected patients. It still requires invasive arterial monitoring and does not prevent vascular complications, and conversion to general anesthesia must always remain available.
- During one-lung ventilation for a thoracoscopic lobectomy, the patient's oxygen saturation falls to 86 percent. After confirming correct tube position and increasing the inspired oxygen, which next maneuver most directly improves oxygenation?
- Immediately resuming two-lung ventilation without surgeon coordination
- Discontinuing all positive end-expiratory pressure to the dependent lung
- Applying continuous positive airway pressure to the nondependent operative lung
- Switching to a smaller tidal volume on the dependent lung only
Correct answer: Applying continuous positive airway pressure to the nondependent operative lung
When hypoxemia persists during one-lung ventilation despite high inspired oxygen and confirmed tube position, applying continuous positive airway pressure to the collapsed nondependent lung delivers some oxygen to its perfused alveoli and raises saturation. Removing positive end-expiratory pressure from the dependent lung would worsen its atelectasis, and abruptly resuming two-lung ventilation without surgeon coordination disrupts the operative field and is reserved for refractory desaturation.
- Which physiologic mechanism normally helps preserve arterial oxygenation during one-lung ventilation by diverting blood away from the collapsed lung?
- Increased dead space in the dependent ventilated lung
- Systemic vasodilation lowering pulmonary pressures
- Hypoxic pulmonary vasoconstriction in the nonventilated lung
- Reflex bronchodilation of the operative lung
Correct answer: Hypoxic pulmonary vasoconstriction in the nonventilated lung
Hypoxic pulmonary vasoconstriction redirects blood flow away from the poorly oxygenated, collapsed nondependent lung toward the ventilated dependent lung, reducing shunt and helping maintain arterial oxygenation during one-lung ventilation. Volatile anesthetics can blunt this protective reflex, which is why excessive concentrations may worsen hypoxemia, whereas systemic vasodilation, dead space changes, and bronchodilation do not provide this shunt-reducing effect.
- A parturient suddenly develops cardiovascular collapse, hypoxemia, and disseminated intravascular coagulation immediately after delivery. Which obstetric catastrophe does this rapid triad most strongly suggest?
- Aspiration pneumonitis
- Amniotic fluid embolism
- Postdural puncture headache
- Local anesthetic systemic toxicity
Correct answer: Amniotic fluid embolism
Amniotic fluid embolism classically presents with abrupt cardiovascular collapse, profound hypoxemia, and disseminated intravascular coagulation occurring around the time of delivery, reflecting an anaphylactoid-like reaction to fetal antigens entering the maternal circulation. This sudden triad distinguishes it from local anesthetic toxicity, aspiration, or a dural-puncture headache, none of which produces this combination of shock, hypoxia, and coagulopathy.
- When amniotic fluid embolism is suspected during a cesarean delivery and the patient deteriorates into cardiac arrest, which management principle is most critical for the anesthesia team?
- Withholding chest compressions until the diagnosis is confirmed by laboratory testing
- High-quality cardiopulmonary resuscitation with prompt consideration of perimortem cesarean delivery and aggressive treatment of coagulopathy
- Administering dantrolene as the primary therapy
- Avoiding blood products to limit transfusion reactions
Correct answer: High-quality cardiopulmonary resuscitation with prompt consideration of perimortem cesarean delivery and aggressive treatment of coagulopathy
Amniotic fluid embolism with arrest is managed with immediate high-quality resuscitation, left uterine displacement or prompt perimortem cesarean delivery to improve maternal circulation, and aggressive correction of the accompanying coagulopathy with blood products. Treatment is supportive and must begin at once rather than awaiting laboratory confirmation, dantrolene has no role, and blood products are essential, not avoided.
- A parturient with severe preeclampsia is receiving a magnesium sulfate infusion and reports loss of her patellar reflexes with new respiratory depression. What is the most appropriate immediate intervention?
- Stopping the magnesium infusion and administering intravenous calcium
- Giving an additional dose of an ergot uterotonic
- Increasing the magnesium infusion rate to control seizures
- Administering dantrolene for the muscle weakness
Correct answer: Stopping the magnesium infusion and administering intravenous calcium
Loss of deep tendon reflexes followed by respiratory depression signals magnesium toxicity, so the infusion is stopped immediately and intravenous calcium is given to antagonize magnesium's neuromuscular and cardiac effects while ventilation is supported. Increasing the magnesium would worsen toxicity, and ergot agents or dantrolene do not address magnesium overdose.
- A patient with HELLP syndrome presents for cesarean delivery. Which laboratory abnormality most directly influences the decision about whether neuraxial anesthesia can be safely performed?
- Elevated serum uric acid
- Mildly elevated blood glucose
- An isolated elevation in serum sodium
- Thrombocytopenia from the low platelet count
Correct answer: Thrombocytopenia from the low platelet count
HELLP syndrome includes hemolysis, elevated liver enzymes, and low platelets, and the thrombocytopenia is the key factor in deciding on neuraxial anesthesia because a low platelet count raises the risk of epidural or spinal hematoma. Uric acid, glucose, and sodium values do not bear on the bleeding risk of placing a neuraxial block in this setting.
- A patient with severe preeclampsia undergoing cesarean delivery requires general anesthesia because of coagulopathy. Why must the team plan carefully for the laryngoscopy and intubation in this patient?
- Because airway edema and an exaggerated hypertensive response to intubation can precipitate cerebral hemorrhage
- Because preeclampsia abolishes the hemodynamic response to laryngoscopy
- Because succinylcholine cannot be used in any preeclamptic patient
- Because volatile agents are contraindicated in preeclampsia
Correct answer: Because airway edema and an exaggerated hypertensive response to intubation can precipitate cerebral hemorrhage
Preeclampsia is associated with significant airway edema and an exaggerated sympathetic hypertensive response to laryngoscopy, which can spike blood pressure dangerously and precipitate intracranial hemorrhage, so the team prepares for a difficult airway and blunts the pressor response. The hemodynamic response is amplified rather than abolished, and volatile agents and succinylcholine remain usable in preeclampsia.
- A 3-year-old child is brought to the operating room for tonsillectomy and adenoidectomy. Compared with adults, which airway and respiratory feature increases this child's risk of rapid desaturation during induction?
- A larger functional residual capacity that buffers apnea
- A lower oxygen consumption per kilogram than adults
- A slower respiratory rate that conserves oxygen
- A higher oxygen consumption combined with a smaller functional residual capacity
Correct answer: A higher oxygen consumption combined with a smaller functional residual capacity
Young children have a high oxygen consumption per kilogram and a proportionally smaller functional residual capacity, so their oxygen reserve is quickly exhausted and they desaturate far faster than adults during apnea at induction. Their oxygen demand is higher, not lower, and their reserve is smaller rather than buffering, which underlies the need for efficient airway management.
- A child develops laryngospasm during emergence from general anesthesia after a tonsillectomy. After applying continuous positive airway pressure with 100 percent oxygen and a jaw-thrust fails to break the spasm, which next step is most appropriate?
- Giving a bolus of an inhaled bronchodilator through the circuit
- Administering a small dose of propofol or succinylcholine to relax the laryngeal muscles
- Immediately performing an emergency surgical airway
- Withholding all medication and waiting for the spasm to resolve on its own
Correct answer: Administering a small dose of propofol or succinylcholine to relax the laryngeal muscles
When positive pressure and jaw thrust fail to break pediatric laryngospasm, deepening with a small dose of propofol or administering succinylcholine relaxes the laryngeal muscles and restores ventilation before hypoxia worsens. Waiting passively risks severe hypoxia and bradycardia, a surgical airway is a last resort, and a bronchodilator does not relieve glottic closure.
- A neonate presents for emergency repair of a tracheoesophageal fistula with esophageal atresia. Which intraoperative concern is most specific to the presence of the fistula during positive-pressure ventilation?
- Inability to maintain normothermia regardless of technique
- Gastric distension from gas passing through the fistula, impairing ventilation
- Sudden onset of malignant hyperthermia
- Excessive systemic absorption of local anesthetic
Correct answer: Gastric distension from gas passing through the fistula, impairing ventilation
With a tracheoesophageal fistula, positive-pressure ventilation can force gas through the fistula into the stomach, causing gastric distension that splints the diaphragm and impairs ventilation, so tube positioning below the fistula and careful ventilation are critical. This mechanical problem is specific to the fistula and is unrelated to local anesthetic absorption or malignant hyperthermia.
- An anesthesia provider plans induction for a healthy but anxious 4-year-old without intravenous access. Which induction approach is most commonly used and best suited to this child?
- A high spinal anesthetic as the sole technique
- Rapid sequence intravenous induction before any access is obtained
- An inhalational (mask) induction with a volatile agent followed by placement of intravenous access
- Awake fiberoptic intubation
Correct answer: An inhalational (mask) induction with a volatile agent followed by placement of intravenous access
For a cooperative or anxious young child without intravenous access, an inhalational mask induction with a volatile agent such as sevoflurane is the standard approach, allowing the child to become anesthetized before an intravenous line is placed. Awake fiberoptic intubation, intravenous rapid sequence before access exists, and a sole high spinal are not appropriate routine techniques for this healthy preschooler.
- A frail older adult is scheduled for elective surgery and is identified preoperatively as frail with limited physiologic reserve. How should this frailty most influence the anesthetic plan?
- It should lead to routine deep sedation to keep the patient comfortable
- It should favor careful drug titration, multimodal opioid-sparing analgesia, and delirium-prevention strategies
- It should prompt no change, since age alone determines management
- It should mandate general anesthesia for every procedure
Correct answer: It should favor careful drug titration, multimodal opioid-sparing analgesia, and delirium-prevention strategies
Frailty predicts poorer perioperative outcomes, so the plan emphasizes cautious titration of anesthetics, opioid-sparing multimodal analgesia, maintenance of physiology, and measures to prevent postoperative delirium and functional decline. Frailty is more informative than chronologic age alone, does not require general anesthesia for every case, and deep sedation can actually increase delirium risk.
- A patient with severe obesity is being preoxygenated before rapid sequence induction. Which positioning maneuver best improves preoxygenation and prolongs the safe apnea time in this patient?
- Turning the patient fully prone for induction
- Placing the patient flat in the supine position
- Using a head-up or ramped position to align the airway and improve functional residual capacity
- Placing the patient in steep head-down Trendelenburg
Correct answer: Using a head-up or ramped position to align the airway and improve functional residual capacity
A head-up or ramped position improves functional residual capacity, reduces the weight of the chest and abdomen on the lungs, and aligns the airway axes, which enhances preoxygenation and lengthens the time to desaturation in patients with severe obesity. A flat supine position worsens functional residual capacity, and Trendelenburg or prone positioning is not used for induction in this setting.
- When dosing anesthetic drugs for a patient with severe obesity, which body weight scalar is generally most appropriate for a lipophilic maintenance infusion versus a single induction bolus of certain agents?
- Drug dosing must be individualized, with some agents dosed on lean or ideal body weight and others on total or adjusted body weight
- Always use total body weight for every drug
- Body weight is irrelevant to dosing in obesity
- Always use ideal body weight for every drug
Correct answer: Drug dosing must be individualized, with some agents dosed on lean or ideal body weight and others on total or adjusted body weight
Dosing in severe obesity is drug-specific: lipophilicity, volume of distribution, and clearance determine whether an agent should be scaled to lean, ideal, adjusted, or total body weight, so a single weight scalar cannot be applied to all drugs. For example, succinylcholine is dosed on total body weight while many induction agents use lean or adjusted weight, making individualized dosing the correct principle.
- A patient is scheduled for a magnetic resonance imaging study under general anesthesia in the imaging suite. Which hazard is uniquely critical to the anesthesia provider in this non-operating-room environment?
- The absence of any need for patient monitoring during imaging
- A guaranteed inability to resuscitate the patient if needed
- The strong static magnetic field, which attracts ferromagnetic objects and can damage or interfere with equipment
- An inability to deliver any inhaled anesthetic in the scanner
Correct answer: The strong static magnetic field, which attracts ferromagnetic objects and can damage or interfere with equipment
The magnetic resonance environment has a powerful static magnetic field that can turn ferromagnetic objects into dangerous projectiles and disrupt monitors and pumps, so only magnetic-resonance-compatible equipment is used and strict screening is enforced. Inhaled anesthesia and full monitoring are still provided with compatible equipment, and resuscitation plans include moving the patient out of the magnet's zone.
- A patient receiving repeated electroconvulsive therapy treatments has poor seizure quality on the current session. Which anesthetic agent is generally preferred because it tends to have minimal anticonvulsant effect and may support adequate seizure duration?
- A deep volatile anesthetic maintained throughout
- Methohexital or another agent chosen to avoid excessive seizure suppression
- A high dose of a benzodiazepine
- A long-acting barbiturate infusion
Correct answer: Methohexital or another agent chosen to avoid excessive seizure suppression
For electroconvulsive therapy, induction agents such as methohexital are favored because they provide rapid hypnosis with relatively little anticonvulsant effect, helping preserve the therapeutic seizure duration. Benzodiazepines and long-acting barbiturates raise the seizure threshold and shorten seizures, and a deep volatile anesthetic is not the standard approach for routine electroconvulsive therapy.
- A patient with a known history of severe coronary artery disease is undergoing off-pump coronary artery bypass grafting. During positioning of the heart for grafting of the lateral wall, the blood pressure falls sharply. What is the most likely cause of this hemodynamic change?
- Reversal of the heparin anticoagulation
- A drug error with the anesthetic agent
- Onset of malignant hyperthermia
- Mechanical compression and displacement of the heart impairing venous return and filling
Correct answer: Mechanical compression and displacement of the heart impairing venous return and filling
During off-pump coronary artery bypass, lifting and rotating the beating heart to expose lateral and posterior vessels mechanically compresses the chambers and impairs venous return and ventricular filling, causing hypotension that the team manages with volume, positioning, and pressor support. This positional effect, not a drug error, malignant hyperthermia, or heparin reversal, explains the sudden pressure drop.
- A patient undergoing open repair of an infrarenal abdominal aortic aneurysm is about to have the aortic cross-clamp applied. What hemodynamic change should the anesthesia provider anticipate at the moment of clamping?
- An abrupt increase in afterload causing hypertension proximal to the clamp
- A sudden fall in afterload and hypotension
- No change in blood pressure during clamping
- Immediate profound bradycardia from vagal stimulation
Correct answer: An abrupt increase in afterload causing hypertension proximal to the clamp
Applying the aortic cross-clamp suddenly increases left ventricular afterload and causes hypertension proximal to the clamp, increasing myocardial work and wall stress, which the provider blunts with vasodilators or deeper anesthesia. Unclamping produces the opposite problem of hypotension from reperfusion, so anticipating the clamp-related afterload surge is essential for vascular cases.
- During open abdominal aortic aneurysm repair, the surgeon prepares to release the aortic cross-clamp. Which intervention best prepares the patient for the expected hemodynamic effect of unclamping?
- Giving a large dose of a beta-blocker immediately before release
- Hyperventilating the patient to a very low carbon dioxide level
- Ensuring adequate volume loading and coordinating gradual clamp release to limit declamping hypotension
- Deepening the anesthetic and giving vasodilators just before release
Correct answer: Ensuring adequate volume loading and coordinating gradual clamp release to limit declamping hypotension
Releasing the aortic cross-clamp causes a sharp fall in afterload plus washout of vasoactive and acidic metabolites from ischemic tissue, producing declamping hypotension, so the provider volume-loads in advance and the surgeon releases the clamp gradually with communication. Deepening anesthesia, beta-blockade, or hyperventilation before unclamping would worsen the hypotension rather than prevent it.
- A patient undergoing a robotic-assisted laparoscopic prostatectomy is placed in steep Trendelenburg with carbon dioxide pneumoperitoneum for a prolonged period. Which physiologic consequence should the anesthesia provider most anticipate?
- Increased airway pressures, reduced lung compliance, and facial and airway edema
- A marked fall in arterial carbon dioxide
- Improved functional residual capacity from the positioning
- Decreased intracranial and intraocular pressure
Correct answer: Increased airway pressures, reduced lung compliance, and facial and airway edema
Steep Trendelenburg combined with carbon dioxide pneumoperitoneum pushes the abdominal contents against the diaphragm and shifts fluid cephalad, raising airway pressures, lowering lung compliance, and producing facial, conjunctival, and airway edema over a long case. The same conditions raise rather than lower intracranial and intraocular pressure, tend to increase absorbed carbon dioxide, and reduce functional residual capacity.
- A patient with a history of a prior episode suggestive of malignant hyperthermia is scheduled for a procedure under the care of a CRNA. Which anesthetic plan is most appropriate to safely care for this susceptible patient?
- Use a standard volatile anesthetic but keep dantrolene nearby
- Avoid all anesthesia and perform the case awake without analgesia
- Use succinylcholine for rapid sequence but avoid volatile agents only
- Provide a nontriggering anesthetic avoiding volatile agents and succinylcholine, with a prepared machine and dantrolene available
Correct answer: Provide a nontriggering anesthetic avoiding volatile agents and succinylcholine, with a prepared machine and dantrolene available
A malignant-hyperthermia-susceptible patient receives a nontriggering technique that avoids all volatile anesthetics and succinylcholine, using agents such as propofol, opioids, and nondepolarizing relaxants on a flushed or vapor-free machine with dantrolene immediately available. Using a volatile agent or succinylcholine would risk triggering a crisis, and performing the case awake without analgesia is neither necessary nor humane.
- A patient with a documented spinal cord injury at the sixth thoracic level undergoes a cystoscopy and develops sudden severe hypertension, bradycardia, and a pounding headache during bladder distension. Which condition does this represent?
- Autonomic dysreflexia
- Local anesthetic systemic toxicity
- Malignant hyperthermia
- A simple vasovagal episode
Correct answer: Autonomic dysreflexia
In a patient with a spinal cord injury above the major splanchnic outflow, a noxious stimulus below the lesion such as bladder distension triggers autonomic dysreflexia, producing severe hypertension, reflex bradycardia, and headache, which is treated by removing the stimulus and giving fast-acting antihypertensives. This pattern is distinct from malignant hyperthermia, local anesthetic toxicity, or a vasovagal faint, which do not present with this dangerous hypertensive surge from a stimulus below the injury.
- A pediatric patient with a single-ventricle physiology who has undergone a Fontan procedure presents for noncardiac surgery. Which hemodynamic principle is most important because pulmonary blood flow in Fontan physiology is passive?
- Dehydration improves cardiac output in Fontan patients
- High airway pressures improve pulmonary blood flow and should be maximized
- Aggressive positive end-expiratory pressure is always beneficial
- Maintaining adequate preload and low pulmonary vascular resistance is essential to preserve passive pulmonary flow
Correct answer: Maintaining adequate preload and low pulmonary vascular resistance is essential to preserve passive pulmonary flow
In Fontan physiology, systemic venous blood flows passively to the lungs without a pumping ventricle, so adequate preload and low pulmonary vascular resistance are critical, and factors that raise pulmonary resistance or excessive airway pressure impede pulmonary flow and cardiac output. High airway pressures, aggressive positive end-expiratory pressure, and hypovolemia all reduce passive pulmonary blood flow and are harmful in these patients.
- A patient with longstanding poorly controlled diabetes presents for foot surgery. Beyond glucose management, which airway-related concern is specifically associated with chronic diabetes?
- Stiff joint syndrome causing limited atlanto-occipital mobility and potential difficult intubation
- An inability to use any neuraxial technique
- Reduced risk of gastroparesis and aspiration
- A guaranteed easy airway in all diabetic patients
Correct answer: Stiff joint syndrome causing limited atlanto-occipital mobility and potential difficult intubation
Longstanding diabetes can cause stiff joint syndrome with glycosylation of tissues that limits cervical and atlanto-occipital mobility, contributing to difficult laryngoscopy, classically suggested by the inability to approximate the palms (prayer sign). Diabetic patients are also at higher risk for gastroparesis and aspiration rather than lower, and neuraxial techniques are not categorically prohibited.
- A patient with severe chronic obstructive pulmonary disease requires general anesthesia for an upper abdominal procedure. Which ventilation strategy best reduces the risk of dynamic hyperinflation and breath stacking in this patient?
- Continuous high positive end-expiratory pressure without regard to exhalation
- A prolonged expiratory time with an adequate expiratory phase to allow full exhalation
- A rapid respiratory rate with short expiratory time
- High tidal volumes with minimal expiratory time
Correct answer: A prolonged expiratory time with an adequate expiratory phase to allow full exhalation
Patients with severe obstructive lung disease have prolonged expiratory airflow, so allowing adequate expiratory time prevents air trapping, dynamic hyperinflation, and intrinsic positive end-expiratory pressure that can cause hypotension and barotrauma. A rapid rate with short expiration or high tidal volumes with little expiratory time worsens breath stacking, making a longer expiratory phase the protective strategy.
- A patient with a history of a kidney transplant on immunosuppression presents for an unrelated surgery. Which anesthetic consideration is most important regarding neuromuscular blocking agents in a patient with significant renal impairment?
- Avoiding all neuromuscular monitoring
- Choosing a relaxant with organ-independent elimination such as cisatracurium to avoid prolonged blockade
- Using only relaxants that depend entirely on renal excretion
- Giving a fixed maximal dose regardless of renal function
Correct answer: Choosing a relaxant with organ-independent elimination such as cisatracurium to avoid prolonged blockade
In renal impairment, relaxants that rely on renal excretion can accumulate and prolong blockade, so an agent like cisatracurium that is cleared by organ-independent Hofmann elimination is favored and titrated with neuromuscular monitoring. Relying on renally excreted relaxants, abandoning monitoring, or giving fixed maximal doses would increase the risk of residual paralysis in these patients.
- A patient undergoing radical neck dissection near the carotid sinus suddenly develops profound bradycardia and hypotension during surgical manipulation. What is the most appropriate immediate action?
- Begin rapid blood transfusion as the first step
- Deepen the volatile anesthetic to treat the heart rate
- Ask the surgeon to stop the manipulation and consider infiltrating the area with local anesthetic
- Administer dantrolene for the bradycardia
Correct answer: Ask the surgeon to stop the manipulation and consider infiltrating the area with local anesthetic
Stimulation of the carotid sinus during neck surgery can trigger a baroreceptor reflex causing bradycardia and hypotension, so the first step is to have the surgeon stop manipulating the area, after which local anesthetic infiltration of the carotid sinus can blunt the reflex and an anticholinergic may be given. Dantrolene, deeper volatile anesthetic, and transfusion do not address this reflex bradycardia.
- A patient is undergoing functional endoscopic sinus surgery and the surgeon requests a relatively bloodless field. Which anesthetic technique most appropriately reduces surgical-site bleeding while maintaining organ perfusion?
- Inducing extreme hypotension well below the limits of autoregulation
- A controlled, modest reduction in blood pressure with reverse Trendelenburg positioning and adequate depth of anesthesia
- Hyperventilating the patient to a very low carbon dioxide level to vasoconstrict
- Maintaining hypertension to keep the patient safe
Correct answer: A controlled, modest reduction in blood pressure with reverse Trendelenburg positioning and adequate depth of anesthesia
A controlled hypotensive technique with modest blood pressure reduction, head-up reverse Trendelenburg positioning, and adequate anesthetic depth improves the surgical field for sinus surgery while keeping perfusion within autoregulatory limits. Driving the pressure to extremes risks organ ischemia, maintaining hypertension worsens bleeding, and aggressive hyperventilation is not the intended technique for field optimization.
- A patient with a history of severe pulmonary hypertension presents for noncardiac surgery. Which intraoperative factor is most important to avoid because it can precipitate a life-threatening rise in pulmonary artery pressure and right ventricular failure?
- Hypoxemia, hypercarbia, and acidosis, which raise pulmonary vascular resistance
- Keeping the patient warm and comfortable
- Avoiding excessive fluid administration
- Maintaining normocapnia and adequate oxygenation
Correct answer: Hypoxemia, hypercarbia, and acidosis, which raise pulmonary vascular resistance
In pulmonary hypertension, hypoxemia, hypercarbia, and acidosis all increase pulmonary vascular resistance and can precipitate acute right ventricular failure, so they are vigilantly avoided while oxygenation and ventilation are optimized. Maintaining normocapnia and oxygenation, avoiding fluid overload, and keeping the patient warm are protective rather than provocative measures in these patients.
- A geriatric patient is at high risk for postoperative cognitive dysfunction after major surgery. Which intraoperative strategy is best supported as part of an effort to reduce this risk?
- Routinely targeting deep anesthesia to ensure unconsciousness
- Maximizing benzodiazepine premedication in all elderly patients
- Withholding all analgesia to avoid sedating the patient
- Avoiding excessively deep anesthesia using processed EEG guidance and minimizing deliriogenic medications
Correct answer: Avoiding excessively deep anesthesia using processed EEG guidance and minimizing deliriogenic medications
Avoiding unnecessarily deep anesthesia, often guided by processed EEG monitoring, and limiting deliriogenic drugs such as benzodiazepines are strategies aimed at reducing postoperative cognitive dysfunction and delirium in older patients. Routinely deep anesthesia and liberal benzodiazepines increase risk, and withholding analgesia worsens delirium because uncontrolled pain is itself a precipitant.
- A parturient with a complete placenta previa is scheduled for cesarean delivery. Why must the anesthesia team prepare specifically for the possibility of major hemorrhage in this patient?
- Because the condition triggers malignant hyperthermia
- Because previa makes neuraxial anesthesia impossible
- Because placenta previa eliminates the risk of bleeding
- Because the abnormally implanted placenta over the cervical os predisposes to heavy intraoperative and postpartum hemorrhage
Correct answer: Because the abnormally implanted placenta over the cervical os predisposes to heavy intraoperative and postpartum hemorrhage
Placenta previa, with the placenta implanted over the cervical os, predisposes to substantial intraoperative and postpartum bleeding, so the team secures large-bore access, ensures blood product availability, and prepares for potential massive transfusion. Previa increases rather than eliminates bleeding risk, does not by itself preclude neuraxial anesthesia in stable patients, and is unrelated to malignant hyperthermia.
- A patient undergoing a liver transplant enters the reperfusion phase as the surgeon unclamps the portal vein and the new graft is perfused. Which hemodynamic and metabolic disturbance should the anesthesia provider most anticipate at reperfusion?
- A sustained hypertensive crisis requiring vasodilators
- An isolated rise in arterial oxygen with no other change
- Postreperfusion syndrome with hypotension, hyperkalemia, and acidosis
- Profound hypothermia-resistant fever
Correct answer: Postreperfusion syndrome with hypotension, hyperkalemia, and acidosis
When the liver graft is reperfused, cold, acidotic, potassium-rich blood and vasoactive mediators wash into the circulation, producing postreperfusion syndrome marked by hypotension, hyperkalemia, acidosis, and possible arrhythmia, which the provider treats with vasopressors, calcium, and correction of potassium and acid-base status. This is a hypotensive, not hypertensive, event and is far more than an isolated change in oxygenation, so anticipating the reperfusion disturbance is key in transplant anesthesia.
