FREE CCRN Study Guide 2026: A Complete, AACN-Aligned Walkthrough

This free CCRN study guide walks through the highest-yield content the AACN Critical Care Registered Nurse (Adult) exam tests, organized by the six content areas of the current AACN test plan — five body-system clinical areas plus the Synergy Model.^[2]

It is interactive, not a wall of text: every content area has worked clinical scenarios, comparison tables, labeled diagrams, and built-in flashcards, taught the way the CCRN actually tests critical care — recognizing instability early, interpreting hemodynamics and ABGs, and managing shock, ventilation, and the failing organ.

Read it content area by content area, then round out your prep with our practice questions and flashcards. The CCRN validates the knowledge a nurse needs to care for the most acutely and critically ill adult patients — a step up in acuity from the progressive-care PCCN.

CCRN Exam Snapshot

The clinical block dominates the exam: Clinical Judgment is 80%, split across the body systems, with Professional Caring & Ethical Practice (the Synergy competencies) the remaining 20%. Under the test plan effective November 12, 2025, the body systems are grouped into five weighted clusters rather than listed one by one — budget your study toward the heaviest clusters first.^[2][3]

Percentages are from AACN’s current Adult CCRN test plan (effective November 12, 2025), which regrouped and re-weighted the body systems — older per-system percentages (Cardiovascular 17%, Pulmonary 17%, and so on) no longer apply. The combined endocrine/heme/GI/renal cluster and the musculoskeletal/neurological/psychosocial cluster are now the two largest clinical blocks.^[2][3]

How the CCRN Is Built: the Synergy Model

The CCRN is built on the AACN Synergy Model for Patient Care, whose core idea is that patient outcomes are best when the nurse’s competencies match the patient’s characteristics and needs. The model defines eight nurse competencies: Clinical Judgment — the clinical block that is 80% of the exam — plus seven that make up the Professional Caring & Ethical Practice domain (the remaining 20%).^[2]

Clinical Judgment is not a separate body system — it runs through every clinical question. The exam rewards the nurse who can take a global grasp of an unstable patient, anticipate deterioration, and act on the highest-priority problem first. Learn the recurring frameworks of critical care — read the hemodynamics, read the ABG, identify the shock state, and treat the cause — and most clinical questions become applications of them.

Cardiovascular

Cardiovascular is 13% of the exam.^[2] It is built on reading the circulation — the hemodynamic numbers that tell you whether the problem is volume, the pump, or the vessels — and on the acute coronary, heart-failure, and rhythm emergencies that fill a critical-care unit. Master the hemodynamic profile of each shock state and you own a large share of the whole exam, not just this cluster.

Hemodynamic Monitoring

Invasive monitoring is a defining CCRN skill. An arterial line gives beat-to-beat blood pressure and the mean arterial pressure; a central line measures central venous pressure (right-heart preload); and a pulmonary artery catheter measures the pulmonary capillary wedge pressure (left-heart preload), cardiac output, and systemic vascular resistance (the left-heart afterload).^[4]

The numbers tell a story. A low CVP and PCWP with a low cardiac output is hypovolemia; a high PCWP with a low cardiac output is pump failure; and a low SVR with a high or normal cardiac output points to distributive (septic) shock. Reading that pattern is the single most testable hemodynamic skill on the exam.

Acute Coronary Syndromes

Acute coronary syndrome ranges from unstable angina through NSTEMI to STEMI. A STEMI (ST-elevation on the ECG, a complete coronary occlusion) needs emergent reperfusion — primary PCI within 90 minutes, or fibrinolysis if PCI is not available in time. Initial care is the familiar bundle: aspirin, oxygen if hypoxic, nitroglycerin for ischemic pain (avoid it in right-ventricular infarction and with recent phosphodiesterase inhibitors), and an anticoagulant.^[4]

The nurse’s job is to recognize the infarct, get the 12-lead and troponin, treat the pain and the rhythm, and watch for the complications — a new murmur (papillary muscle or septal rupture), heart failure, and the lethal arrhythmias. An inferior/right-ventricular MI is preload-dependent: give fluids and avoid nitrates, which can drop the pressure dangerously.

Heart Failure & Cardiogenic Shock

Acute decompensated heart failure presents with pulmonary edema, dyspnea, and a high filling pressure. When the pump fails badly enough to cause hypoperfusion, it becomes cardiogenic shock: a high wedge pressure with a low cardiac output and a compensatory high SVR — the patient is cold, clammy, and often in pulmonary edema.

Treatment supports the failing pump rather than simply adding volume: an inotrope such as dobutamine or milrinone to raise contractility and cardiac output, careful diuresis or vasodilation to unload a congested ventricle, and mechanical circulatory support — an intra-aortic balloon pump or a ventricular assist device — when drugs are not enough. This invasive, unstable management is exactly where the CCRN scope sits above the progressive-care PCCN.

Dysrhythmias, Tamponade & Vascular Crises

Know the unstable rhythms and their treatments: a patient with a tachy- or bradydysrhythmia who is hypotensive, altered, ischemic, or in shock gets electrical therapy — synchronized cardioversion for unstable tachycardias with a pulse, defibrillation for pulseless VT/VF, and pacing or atropine for unstable bradycardia. Recognize the conduction defects the test plan names — prolonged QT (a torsades risk) and Wolff-Parkinson-White.^[2]

Cardiac tamponade is obstructive shock from fluid compressing the heart — Beck’s triad (hypotension, jugular venous distension, muffled heart sounds) and pulsus paradoxus — relieved with pericardiocentesis. The vascular crises include aortic aneurysm and aortic dissection, where you control heart rate and blood pressure tightly (a beta-blocker before a vasodilator) to limit aortic wall shear.

Respiratory

Respiratory is 12% of the exam.^[2] It is anchored by two skills the CCRN tests relentlessly — interpreting the arterial blood gas and managing the ventilated patient — plus the acute respiratory emergencies (ARDS, respiratory failure, pulmonary embolism, and pleural disease). The recurring theme is supporting oxygenation and ventilation without injuring the lung.

ABG Interpretation

Read every ABG the same way, in three steps. First the pH (7.35–7.45): below is acidosis, above is alkalosis. Second the primary driver: if the PaCO₂ (35–45) moves opposite to the pH, it is respiratory; if the HCO₃⁻ (22–26) moves the same direction as the pH, it is metabolic. Third, the degree of compensation.^[4]

For a metabolic acidosis, calculate the anion gap(Na − [Cl + HCO₃], normal 8–12): a high gap points to added acid (the MUDPILES causes — including DKA, lactic acidosis, and toxins) and a normal gap to bicarbonate loss (diarrhea, renal tubular acidosis).

ARDS & Acute Respiratory Failure

ARDS is acute, non-cardiogenic pulmonary edema from diffuse alveolar injury: bilateral infiltrates with refractory hypoxemia and a PaO₂/FiO₂ ratio of 300 or less (≤200 moderate, ≤100 severe). The cornerstone is lung-protective ventilation — low tidal volumes (~6 mL/kg ideal body weight), a plateau pressure under 30 cmH₂O, PEEP titration, and permissive hypercapnia. Prone positioningimproves oxygenation and survival in moderate-to-severe ARDS and is named in the CCRN test plan’s testable nursing actions.^[2][4]

Mechanical Ventilation

The CCRN tests the complications of the ventilator as much as the settings. Watch for a sudden high-pressure alarm (a kink, secretions, biting, bronchospasm, or a developing tension pneumothorax) versus a low-pressure alarm (a disconnection or leak).

Prevent ventilator-associated pneumonia with the bundle — head of bed 30–45°, daily sedation interruption and spontaneous breathing trials, oral care, and DVT and stress-ulcer prophylaxis. Know the danger of auto-PEEP (breath stacking) in obstructive disease and the barotrauma risk of high pressures.

When a ventilated patient suddenly desaturates, work the mnemonic DOPE — Displacement of the tube, Obstruction, Pneumothorax, and Equipment failure — and disconnect and bag the patient while you troubleshoot.

Pulmonary Embolism & Pleural Disease

A massive pulmonary embolism causes obstructive shock with acute right-heart strain — sudden hypoxia, hypotension, and signs of RV failure; treat the unstable patient with anticoagulation and, when hemodynamically significant, thrombolysis or embolectomy. A tension pneumothorax is a clinical diagnosis (absent breath sounds, hypotension, JVD, late tracheal deviation) needing immediate needle decompression then a chest tube. Pleural effusions and empyema are drained; manage the chest tube and watch its output.

Endocrine, Hematology, Gastrointestinal, Renal & Integumentary

This combined cluster is the largest clinical area at 21% of the exam.^[2] AACN groups five body systems together here, so it is broad — but the highest-yield topics are predictable: the endocrine emergencies (DKA, HHS, SIADH), the bleeding-and-clotting disorders and transfusion reactions, GI hemorrhage and hepatic failure, acute kidney injury with electrolyte crises, and the skin failures of the critically ill.

Endocrine Emergencies (DKA / HHS / SIADH)

Diabetic ketoacidosis (glucose >250, pH <7.3, ketones, a high-anion-gap acidosis) and hyperosmolar hyperglycemic state (glucose often >600, minimal ketosis, profound dehydration) are treated in the same order: fluids first, then an insulin infusion, with close potassium replacement. Insulin drives potassium into cells, so a normal or low K⁺ can crash dangerously — replace it before or alongside insulin.^[4]

SIADH causes water retention and dilutional hyponatremia with concentrated urine — managed with fluid restriction; it contrasts with diabetes insipidus (large volumes of dilute urine). Also recognize adrenal crisis (hypotension refractory to fluids and pressors → give stress-dose steroids) and thyroid storm and myxedema coma.

Hematology, Immunology & Transfusion

Disseminated intravascular coagulation consumes platelets and clotting factors, causing simultaneous thrombosis and bleeding — treat the underlying cause and support with products. Heparin-induced thrombocytopenia is an immune reaction that drops the platelet count and causes paradoxical clotting; stop all heparin (including flushes) and switch to a non-heparin anticoagulant. Distinguish the two transfusion-reaction look-alikes: TRALI (hypotension, non-cardiogenic edema, no response to diuresis) from TACO (hypertension, volume overload that improves with diuresis).^[4]

Gastrointestinal Emergencies

Acute GI hemorrhage (upper, from peptic ulcers or esophageal varices; or lower) can drive hypovolemic shock fast — resuscitate with blood, correct coagulopathy, and arrange endoscopy; for variceal bleeding, add octreotide and consider balloon tamponade. Recognize hepatic failure (encephalopathy, coagulopathy, portal hypertension), acute pancreatitis, bowel obstruction and ischemia, peritonitis, and abdominal compartment syndrome (a tense, distended abdomen with rising airway pressures and falling urine output — measure bladder pressure).

Renal, Electrolytes & CRRT

Acute kidney injury is common in critical illness (ischemia/acute tubular necrosis, nephrotoxins, sepsis). When the kidneys fail, the hemodynamically unstable patient is dialyzed with continuous renal replacement therapy rather than intermittent hemodialysis, because the slow, continuous removal is better tolerated. The electrolyte emergency to know cold is hyperkalemia.

Integumentary & Wounds

The critically ill are at high risk for skin breakdown — pressure injuries from immobility and poor perfusion, IV infiltration and extravasation injury, and skin failure. Recognize necrotizing fasciitis (pain out of proportion, crepitus, rapid systemic toxicity) as a surgical emergency, and prevent pressure injury with repositioning, support surfaces, and nutrition. Stage pressure injuries correctly and manage wounds as part of the multidisciplinary plan.

Musculoskeletal, Neurological & Behavioral/Psychosocial

This combined cluster is the second-largest clinical area at 18%.^[2] It is dominated by neurological critical care — rising intracranial pressure, stroke, spinal cord injury, and brain death — alongside the musculoskeletal emergencies (especially compartment syndrome) and the behavioral/psychosocial problems of the ICU, above all delirium.

Neurological Emergencies & ICP

Intracranial pressure is normally 5–15 mmHg; the goal is to keep it under about 20–22 while preserving cerebral perfusion pressure (CPP = MAP − ICP). Nursing measures: head of bed at 30° with the head midline, normothermia and normocapnia, avoiding hypoxia and hypotension, minimizing noxious stimulation, and giving hypertonic saline or mannitol for acute spikes.^[4]

The late, ominous sign of dangerously high ICP is a declining level of consciousness with Cushing’s triad (hypertension with a widening pulse pressure, bradycardia, irregular respirations). The overriding principle is to prevent secondary brain injury — a single episode of hypoxia or hypotension worsens outcomes, so protecting oxygenation and blood pressure is the intervention the nurse controls.

Stroke, Spinal Cord Injury & Brain Death

For ischemic stroke, time is brain: confirm the last-known-well time, get the non-contrast CT to rule out hemorrhage, and treat eligible patients with thrombolysis (within the window) and/or mechanical thrombectomy for a large-vessel occlusion.

Hemorrhagic stroke needs blood-pressure control and reversal of anticoagulation. A high spinal cord injury can cause neurogenic shock — hypotension WITH bradycardia and warm, dry skin from lost sympathetic tone (treated with fluids, vasopressors, and atropine). Brain death is the irreversible loss of all brain and brainstem function, confirmed clinically (coma, absent brainstem reflexes, a positive apnea test); the nurse supports the family and the organ-donation process.

Musculoskeletal & Compartment Syndrome

The musculoskeletal emergency is compartment syndrome: rising pressure in a closed fascial compartment that cuts off perfusion. The 6 P’s are pain (out of proportion and on passive stretch — the earliest sign), paresthesia, pallor, pulselessness, paralysis, and poikilothermia; pulselessness and paralysis are late.

Treatment is emergent fasciotomy — do not elevate above the heart or apply ice, and remove constricting dressings. After a crush injury or prolonged immobility, watch for rhabdomyolysis (elevated CK, dark urine, kidney risk) and treat with aggressive IV fluids.

Behavioral, Psychosocial & ICU Delirium

ICU delirium is an acute, fluctuating disturbance of attention and awareness — hyperactive (agitated), hypoactive (the quiet, often-missed form), or mixed — screened with the CAM-ICU and linked to worse outcomes and post-intensive care syndrome.

Management is mostly non-pharmacologic, captured in the ABCDEF bundle: minimize sedation, daily awakening and breathing trials, early mobility, reorientation and sleep hygiene, family engagement, and treating pain. Also manage agitation and aggression safely, substance withdrawal, mood disorders, and suicidal ideation/self-harm with appropriate precautions.^[4]

Multisystem

Multisystem is 16% of the exam.^[2] It covers the conditions that cross organ systems — above all sepsis and the shock states — plus cardiac arrest and ACLS, toxicology, burns, and the life-threatening derangements (acid-base, fluid and electrolyte, thermoregulation) that affect the whole patient. This is where the CCRN’s highest-acuity content lives.

Sepsis, SIRS & Septic Shock

Sepsis is life-threatening organ dysfunction from a dysregulated response to infection; septic shock is sepsis with persistent hypotension needing vasopressors to keep the MAP at 65 or above plus a raised lactate despite fluids. The immediate response is the Surviving Sepsis hour-1 bundle.^[5]

Know the related definitions: SIRS is the generalized inflammatory response (which can be non-infectious), and MODS is the progressive failure of two or more organ systems — the leading cause of ICU death. Norepinephrine is the first-line vasopressor for septic shock; vasopressin is added when it is not enough.

Shock States & MODS

Tie the cluster together with the four shock states and their hemodynamic fingerprints — the single highest-yield framework on the exam.

Match the treatment to the cause: fluids/blood for hypovolemic, an inotrope and mechanical support for cardiogenic, fluids plus norepinephrine for distributive (septic), epinephrine for anaphylactic, and relieving the obstruction (decompress the tension pneumothorax, drain the tamponade, treat the massive PE) for obstructive. Untreated shock of any kind can progress to MODS.

Cardiac Arrest, ACLS & Resuscitation

High-quality CPR is the foundation of ACLS. Sort the arrest rhythm into shockable (ventricular fibrillation and pulseless VT → immediate defibrillation, epinephrine, and an antiarrhythmic such as amiodarone) versus non-shockable(PEA and asystole → CPR and epinephrine every 3–5 minutes, with no defibrillation), and relentlessly search for the reversible causes — the H’s and T’s.^[6] After return of spontaneous circulation, provide post-arrest care, including targeted temperature management.

Toxicology, Burns & Multisystem Crises

Know the common antidotes and toxidromes (naloxone for opioids, flumazenil cautiously for benzodiazepines, N-acetylcysteine for acetaminophen, bicarbonate for tricyclics, digoxin-specific antibody fragments for digoxin). Major burns need airway-first management (intubate early for inhalation injury) and fluid resuscitation. Round out the cluster with thermoregulation emergencies (malignant hyperthermia → dantrolene; environmental hypo- and hyperthermia), submersion injury, healthcare-associated infections, and the life-threatening maternal-fetal emergencies (eclampsia, HELLP, abruption).

Professional Caring & Ethical Practice

Professional Caring & Ethical Practice is 20% of the exam — one in five questions.^[2] It tests the seven non–Clinical-Judgment competencies of the Synergy Model. AACN does not assign individual percentages to these seven in the current plan; learn them as a set, because the questions reward applying the right professional value to a real ICU situation.

Advocacy, Moral Agency & Ethics

Advocacy and moral agencymean working on the patient’s behalf and acting as a moral agent to identify and help resolve ethical and clinical concerns. In practice this is informed consent, surrogate decision-making, honoring advance directives, and speaking up when care conflicts with the patient’s wishes. The ethical principles tested here — autonomy, beneficence, non-maleficence, and justice — show up in end-of-life and goals-of-care dilemmas, where the nurse supports the patient and family and helps manage the conflict that arises when interventions no longer serve the patient.

Caring Practices & Response to Diversity

Caring practices are the activities that create a compassionate, supportive, therapeutic environment — vigilance, engagement, and responsiveness — to promote comfort and healing and prevent unnecessary suffering, including skilled palliative and end-of-life care. Response to diversity is the sensitivity to recognize and incorporate differences (cultural, spiritual, gender, age, socioeconomic, values) into the plan of care, providing culturally responsive, patient-centered care.

Collaboration & Systems Thinking

Collaboration is working with patients, families, and the interdisciplinary team toward optimal, realistic goals — effective handoffs (a structured tool such as SBAR), shared decision-making, and family-centered care. Systems thinking is the body of knowledge and tools that let the nurse manage environmental and system resources across the care continuum — recognizing how a change in one part of the system affects the whole, and navigating resources to get the patient what they need.

Clinical Inquiry & Facilitation of Learning

Clinical inquiry is the ongoing process of questioning and evaluating practice and creating change through evidence-based practice, research utilization, and experiential knowledge — the reason CCRN content is anchored to current guidelines. Facilitation of learning is the ability to teach patients, families, staff, and the community, both formally and informally — discharge teaching, family education at the bedside, and precepting. Together these competencies keep critical care evidence-based and improving.

How to Use This Study Guide

Work through the guide one content area at a time. After each one, check it off in the contents to raise your exam-readiness score, then drill the same content in our free practice questions and flashcards — active recall and timed, domain-weighted practice are what move knowledge into exam-day performance.

• Weight your time by the blueprint. The combined Endocrine/Heme/GI/Renal/Integumentary cluster (21%) and the Musculoskeletal/Neurological/Psychosocial cluster (18%) are the two largest clinical areas — then Multisystem (16%) and the Synergy Model (20%).
• Master the core frameworks first. Hemodynamic values and shock profiles, ABG interpretation, the vasoactive drips, and the Surviving Sepsis bundle recur across every clinical cluster.
• Think in patterns, not facts. Most clinical questions are solved by reading the hemodynamics or the ABG, naming the problem, and treating the cause.
• Don’t skip Professional Caring & Ethical Practice. It is a full 20% — learn the seven Synergy competencies and how to apply them.
• Use the current test plan. AACN regrouped and re-weighted the body systems effective November 12, 2025 — study to the new clusters, not the old per-system percentages.

Common questions CCRN candidates search and get asked — each answered briefly and backed by an official source (AACN, NIH, the Surviving Sepsis Campaign, the AHA, or the CDC). Tap any card to test yourself.

CCRN Glossary

Key CCRN terms in one place. Hover any dotted term throughout the guide for its definition; the full list is below.

CCRN

Critical Care Registered Nurse — the AACN specialty certification validating the knowledge a registered nurse needs to care for acutely and critically ill adult patients.

AACN

American Association of Critical-Care Nurses — through AACN Certification Corporation, the organization that owns and administers the CCRN, PCCN, CCRN-K, and related critical-care credentials.

Synergy Model

The AACN Synergy Model for Patient Care — the framework behind CCRN certification, holding that outcomes are best when the nurse's competencies match the patient's needs.

Clinical Judgment

In the Synergy Model, clinical reasoning — decision-making, critical thinking, and a global grasp of the situation — combined with nursing skills; it is 80% of the CCRN exam.

Professional Caring & Ethical Practice

The 20% of the CCRN exam covering the seven non–Clinical-Judgment Synergy competencies (advocacy, caring practices, collaboration, systems thinking, response to diversity, clinical inquiry, facilitation of learning).

hemodynamics

The pressures and flows of the circulation — preload, afterload, contractility, and cardiac output — measured invasively (arterial line, pulmonary artery catheter) or non-invasively in critical care.

CVP

Central venous pressure (right atrial pressure), normally 2–6 mmHg; a measure of right-heart preload and volume status.

PCWP

Pulmonary capillary wedge pressure (pulmonary artery occlusion pressure), normally 6–12 mmHg; reflects left atrial pressure and therefore left-ventricular preload.

cardiac output

The volume of blood the heart pumps per minute (normally 4–8 L/min); cardiac index (2.5–4.0 L/min/m²) is cardiac output indexed to body surface area.

SVR

Systemic vascular resistance (normally 800–1,200 dynes·s·cm⁻⁵) — the afterload the left ventricle pumps against; it rises in most shock but falls in distributive shock.

MAP

Mean arterial pressure (normally 70–105 mmHg) — the average perfusion pressure over a cardiac cycle; a MAP of at least 65 is the usual resuscitation target.

preload

The stretch on the ventricle at end-diastole (its filling), estimated by CVP for the right heart and PCWP for the left; low in hypovolemic shock, high in cardiogenic shock.

afterload

The resistance the ventricle must overcome to eject blood, largely set by systemic vascular resistance for the left heart.

acute coronary syndrome

A spectrum of myocardial ischemia — unstable angina, NSTEMI, and STEMI — caused by acute reduction of coronary blood flow, usually from a ruptured atherosclerotic plaque.

STEMI

ST-elevation myocardial infarction — a full-thickness infarct from complete coronary occlusion, requiring emergent reperfusion (PCI or fibrinolysis).

cardiogenic shock

Shock from pump failure (often a large MI): a high preload (PCWP) and low cardiac output with a compensatory high SVR; treated with inotropes and mechanical circulatory support.

heart failure

Inability of the heart to pump enough blood to meet the body's needs; acute decompensation causes pulmonary edema and is a leading reason for ICU admission.

cardiac tamponade

Fluid in the pericardial sac compressing the heart, recognized by Beck's triad (hypotension, jugular venous distension, muffled heart sounds) and pulsus paradoxus; treated with pericardiocentesis.

dysrhythmia

An abnormal heart rhythm; the CCRN tests recognition and management of atrial fibrillation, SVT, ventricular tachycardia/fibrillation, heart block, and conduction defects like prolonged QT and Wolff-Parkinson-White.

ABG

Arterial blood gas — measures pH, PaCO₂, PaO₂, and HCO₃⁻ to assess oxygenation, ventilation, and acid-base balance.

ARDS

Acute respiratory distress syndrome — acute, non-cardiogenic pulmonary edema with bilateral infiltrates and refractory hypoxemia (PaO₂/FiO₂ ≤ 300), managed with lung-protective ventilation and prone positioning.

lung-protective ventilation

A ventilation strategy for ARDS using low tidal volumes (~6 mL/kg ideal body weight), a plateau pressure under 30 cmH₂O, PEEP, and permissive hypercapnia to limit ventilator-induced lung injury.

PEEP

Positive end-expiratory pressure — pressure kept in the airways at the end of expiration to hold alveoli open, improve oxygenation, and recruit collapsed lung.

pulmonary embolism

A clot (usually from a deep vein) lodged in the pulmonary circulation; a massive PE causes obstructive shock with acute right-heart strain.

tension pneumothorax

Air trapped under pressure in the pleural space causing obstructive shock — absent breath sounds, hypotension, JVD, and late tracheal deviation; treated with immediate needle decompression then a chest tube.

DKA

Diabetic ketoacidosis — hyperglycemia (>250) with ketosis and a high-anion-gap metabolic acidosis (pH <7.3); treated with fluids, an insulin infusion, and potassium replacement.

HHS

Hyperosmolar hyperglycemic state — severe hyperglycemia (often >600) with profound dehydration and high osmolality but minimal ketosis; treated like DKA with fluids first, then insulin.

SIADH

Syndrome of inappropriate antidiuretic hormone — excess ADH causing water retention and dilutional hyponatremia with concentrated urine; managed with fluid restriction.

DIC

Disseminated intravascular coagulation — widespread activation of clotting that consumes platelets and factors, causing simultaneous thrombosis and bleeding; treat the underlying cause.

HIT

Heparin-induced thrombocytopenia — an immune reaction to heparin causing a falling platelet count and paradoxical thrombosis; stop all heparin and switch to a non-heparin anticoagulant.

TRALI

Transfusion-related acute lung injury — immune-mediated non-cardiogenic pulmonary edema within ~6 hours of transfusion, with hypotension that does NOT improve with diuresis.

TACO

Transfusion-associated circulatory overload — volume overload from transfusion, with hypertension and pulmonary edema that DO improve with diuresis.

acute kidney injury

A rapid decline in kidney function (rising creatinine, falling urine output), often from ischemia/acute tubular necrosis, nephrotoxins, or sepsis; severe cases need renal replacement therapy.

CRRT

Continuous renal replacement therapy — slow, continuous dialysis used for hemodynamically unstable critically ill patients who cannot tolerate intermittent hemodialysis.

hyperkalemia

A dangerously high serum potassium that destabilizes the cardiac membrane (peaked T waves, widening QRS); treat with IV calcium first, then insulin/dextrose and a beta-agonist, then removal.

ICP

Intracranial pressure — normally 5–15 mmHg; sustained elevation above ~20–22 reduces cerebral perfusion and is a neurosurgical emergency.

cerebral perfusion pressure

CPP = mean arterial pressure − intracranial pressure; the net pressure perfusing the brain, kept adequate to prevent secondary ischemic injury.

Cushing's triad

A late, ominous sign of raised intracranial pressure: hypertension with a widening pulse pressure, bradycardia, and irregular respirations.

neurogenic shock

Distributive shock after a high spinal cord injury — loss of sympathetic tone causes hypotension WITH bradycardia and warm, dry skin.

brain death

The irreversible loss of all brain and brainstem function; confirmed clinically (coma, absent brainstem reflexes, apnea test) and legally equivalent to death.

delirium

An acute, fluctuating disturbance of attention and awareness common in the ICU; screened with the CAM-ICU and managed mainly by minimizing sedation and mobilizing early (the ABCDEF bundle).

post-intensive care syndrome

New or worsened physical, cognitive, or mental-health impairment after critical illness, persisting after ICU discharge; reduced by minimizing sedation, early mobility, and delirium prevention.

compartment syndrome

Rising pressure in a closed fascial compartment causing ischemia; the 6 P's (pain, paresthesia, pallor, pulselessness, paralysis, poikilothermia) — a fasciotomy emergency.

rhabdomyolysis

Muscle breakdown releasing myoglobin (e.g., after crush injury or prolonged immobility) that can cause acute kidney injury; marked by elevated CK and dark, tea-colored urine; treated with aggressive IV fluids.

sepsis

Life-threatening organ dysfunction caused by a dysregulated host response to infection; septic shock is sepsis with persistent hypotension needing vasopressors plus a raised lactate despite fluids.

SIRS

Systemic inflammatory response syndrome — a generalized inflammatory state (abnormal temperature, heart rate, respiratory rate, and white-cell count) that may be infectious or non-infectious.

MODS

Multiple organ dysfunction syndrome — progressive failure of two or more organ systems and the leading cause of death in the ICU.

Surviving Sepsis bundle

The Surviving Sepsis Campaign's hour-1 bundle: measure lactate, draw cultures before antibiotics, give broad-spectrum antibiotics, begin 30 mL/kg crystalloid, and start vasopressors to MAP ≥65.

norepinephrine

An α1 ≫ β1 vasopressor; the first-line agent for septic and other distributive shock to raise systemic vascular resistance and mean arterial pressure.

dobutamine

A β1 inotrope that raises contractility and cardiac output while lowering systemic vascular resistance; used in cardiogenic shock and low-output heart failure.

nitroprusside

A balanced arterial and venous vasodilator for hypertensive emergency and aortic dissection; prolonged high-dose use risks cyanide/thiocyanate toxicity, especially in renal failure.

ACLS

Advanced Cardiovascular Life Support — the algorithms for cardiac arrest and peri-arrest, including shockable (VF/pVT) and non-shockable (PEA/asystole) rhythm management and the H's and T's.

H's and T's

The reversible causes of cardiac arrest to identify and treat — Hypovolemia, Hypoxia, Hydrogen ion (acidosis), Hypo-/Hyperkalemia, Hypothermia; Tension pneumothorax, Tamponade, Toxins, and Thrombosis.

CCRN Study Guide FAQ

References

1. 1.American Association of Critical-Care Nurses. “CCRN (Adult) Certification.” AACN. ↑
2. 2.American Association of Critical-Care Nurses. “CCRN Exam Handbook — Direct Care (test plan effective Nov 12, 2025).” AACN. ↑
3. 3.American Association of Critical-Care Nurses. “Revised CCRN Exams Launch Nov 12, 2025.” AACN. ↑
4. 4.National Institutes of Health / National Library of Medicine. “StatPearls & MedlinePlus Clinical Reference (critical-care topics).” NIH/NLM. ↑
5. 5.Society of Critical Care Medicine / Surviving Sepsis Campaign. “Surviving Sepsis Campaign Guidelines & Hour-1 Bundle.” SCCM. ↑
6. 6.American Heart Association. “Advanced Cardiovascular Life Support (ACLS) Guidelines.” American Heart Association. ↑
7. 7.Centers for Disease Control and Prevention (CDC). “Healthcare-Associated Infections & Sepsis.” CDC. ↑

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