FREE CEN Study Guide 2026: A Complete, BCEN-Aligned Walkthrough

This free CEN study guide walks through the highest-yield content the BCEN Certified Emergency Nurse exam tests, organized by the eleven official content areas of the BCEN content outline — from cardiovascular and respiratory emergencies through obstetric, psychiatric, toxicologic, and professional practice.^[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 CEN actually tests emergency nursing — rapid recognition of life threats, prioritizing with triage and the ESI, and the first, safest action across every body system.

Read it content area by content area, then round out your prep with our practice questions and flashcards. The CEN validates the broad knowledge a registered nurse needs to care for any emergency presentation, which is what sets it apart from BCEN’s trauma (TCRN) and flight/transport (CFRN) credentials.

CEN Exam Snapshot

The exam spans every body system, but it leans on the three biggest areas: Cardiovascular (18 questions), Respiratory (17), and Neurological (17) together are about a third of the exam, followed by Medical (15) and Gastrointestinal (14). Budget your study toward the heaviest content areas first.^[2]

Percentages are derived from the official scored-item counts in BCEN’s CEN content outline effective July 2026 (BCEN publishes counts, not percentages); the standard dropped from ten content areas to eleven when gastrointestinal and genitourinary/obstetrical content were split apart.^[2]

How the CEN Is Built: Emergency Nursing Across Every System

The CEN is the general emergency-nursing certification: it tests the broad knowledge an ED nurse needs for any patient who walks (or is wheeled) through the door, across all eleven body systems and the professional practice around them.^[1] That breadth is what makes it different from BCEN’s focused credentials — the trauma-specific TCRN and the flight/transport CFRN.

Two frameworks run through almost every question. The first is prioritization: airway, breathing, and circulation come before everything else, and the “first” or “most important” action is usually the one that protects perfusion and oxygenation. The second is triage — the Emergency Severity Index sorts patients by acuity and resource need, and a chunk of the exam asks you to apply it.

Learn the recognition patterns — the ECG of a STEMI, the signs of tension pneumothorax, Beck’s triad, the four shockstates — and most clinical questions become an application of “recognize it, then take the first, safest action.”

Cardiovascular Emergencies

Cardiovascular is the largest content area at 18 scored questions.^[2] It is dominated by acute coronary syndrome and the 12-lead ECG, the ACLS dysrhythmias and cardiac arrest, heart failure and the shock states, and the high-mortality vascular catastrophes. The recurring theme is fast recognition and time-critical action — minutes change outcomes.

Acute Coronary Syndrome & the 12-Lead

Acute coronary syndrome runs from unstable angina through NSTEMI to STEMI. A STEMI shows ST elevation of at least 1 mm in two or more contiguous leads (or a new left bundle branch block) and an occluded artery that needs reperfusion — primary PCI within 90 minutes door-to-balloon, or fibrinolytics if PCI is unavailable. The first ED bundle for chest pain is a 12-lead ECG within 10 minutes, aspirin, oxygen only if hypoxic (SpO₂ below 90%), nitroglycerin for ongoing pain, and serial troponins.^[9]

Watch for atypical presentations — women, older adults, and people with diabetes may present with dyspnea, fatigue, or epigastric discomfort instead of classic crushing chest pain. Hold nitroglycerin in inferior (right-ventricular) MI and in anyone who has taken a phosphodiesterase inhibitor, because both can cause profound hypotension.

ACLS Dysrhythmias & Arrest

Know the ACLS algorithms cold. For pulseless ventricular fibrillation or tachycardia, defibrillate immediately and give high-quality CPR with epinephrine 1 mg every 3 to 5 minutes and amiodarone for refractory rhythms. Asystole and PEA are not shockable — give CPR and epinephrine and hunt the reversible causes (the H’s and T’s).

Treat symptomatic bradycardia with atropine, then transcutaneous pacing; treat stable narrow-complex SVT with vagal maneuvers and adenosine, and unstable tachycardia with synchronized cardioversion.^[7]

Doses are standard ACLS anchors; confirm against your facility’s current American Heart Association algorithms, which were updated in 2025.^[7]

Heart Failure, Tamponade & Shock

Acute decompensated heart failure causes flash pulmonary edema — dyspnea, crackles, and frothy sputum — and is treated with upright positioning, oxygen or BiPAP, nitrates, and diuretics. Cardiogenic shock from a large MI is pump failure with cold, clammy skin and low output.

Cardiac tamponade (hypotension, JVD, muffled heart sounds, with pulsus paradoxus) is obstructive shock relieved by pericardiocentesis. Recognizing which shock you face determines the fix.

Aortic Dissection, AAA & Hypertensive Crisis

A thoracic aortic dissection classically causes sudden, tearing chest or back pain with a blood-pressure difference between arms and a widened mediastinum; control heart rate and blood pressure aggressively while arranging imaging and surgery. A leaking abdominal aortic aneurysm presents with abdominal or flank pain, a pulsatile mass, and hypotension — a surgical emergency. A hypertensive emergency is severe hypertension with end-organ damage (stroke, MI, encephalopathy, pulmonary edema), treated with a controlled, gradual blood-pressure reduction to avoid organ hypoperfusion.

Respiratory Emergencies

Respiratory is the second-largest area at 17 scored questions.^[2] Airway and oxygenation come first on every respiratory question, so the recurring skill is recognizing the patient who is tiring and heading for failure before they crash.

Asthma & COPD Exacerbations

An asthma or COPD exacerbation presents with wheezing, prolonged expiration, and accessory-muscle use. Treat with inhaled bronchodilators (albuterol plus ipratropium), systemic steroids, and — for COPD — non-invasive ventilation (BiPAP) to buy time. The ominous sign is a silent chest with a tiring, drowsy patient: that is impending respiratory failure, and the answer shifts to preparing for intubation.

Pulmonary Embolism & Pneumothorax

A pulmonary embolism causes sudden dyspnea and pleuritic chest pain with tachycardia and hypoxia but often clear lung sounds; look for risk factors (immobility, recent surgery, cancer, oral contraceptives). Treat with anticoagulation, and thrombolytics for a massive PE with shock. A tension pneumothorax is a clinical diagnosis — absent breath sounds and hyperresonance on one side, hypotension, JVD, and late tracheal deviation — treated with immediate needle decompression then a chest tube; do not wait for a chest film.

Airway Management, ARDS & ABGs

Secure a threatened airway early. Rapid sequence intubation uses a sedative and a paralytic together, and capnography confirms tube placement and tracks perfusion.

ARDS is refractory hypoxemia with bilateral infiltrates that needs lung-protective, low-tidal-volume ventilation. Reading an arterial blood gas is a recurring CEN skill — pH first, then decide whether the CO₂ or the bicarbonate explains it.

Neurological Emergencies

Neurological is tied for the second-largest area at 17 scored questions.^[2] Stroke dominates, alongside increased intracranial pressure, seizures, and the can’t-miss headaches — and almost all of it is time-critical.

Stroke, TIA & the Time Window

Recognize stroke fast with BE-FAST and establish the last-known-well time, which sets treatment eligibility. A non-contrast CT comes first to distinguish an ischemic stroke (a clot) from a hemorrhagic stroke (a bleed) — giving thrombolytics to a bleed would be catastrophic.

Eligible ischemic strokes get IV thrombolytics within the window, and a large-vessel occlusion may get mechanical thrombectomy. A TIA is a transient deficit that fully resolves but is a warning of a future stroke.^[9]

Increased ICP, Seizures & Meningitis

Rising intracranial pressure shows a declining Glasgow Coma Scale and the late Cushing’s triad (hypertension with a widened pulse pressure, bradycardia, irregular respirations); manage with head-of-bed elevation, a midline head, normocapnia, and osmotic therapy. Status epilepticus is a seizure over 5 minutes or repeated seizures without recovery — give a benzodiazepine first, then a longer-acting antiepileptic. Bacterial meningitis (fever, headache, neck stiffness, Kernig/Brudzinski signs) needs early antibiotics and droplet precautions.

Headache & Neuromuscular Disorders

Sort the dangerous headache from the benign one: a “thunderclap” worst-headache-of-life suggests subarachnoid hemorrhage, a headache with fever and neck stiffness suggests meningitis, and a new headache with jaw claudication in an older adult suggests temporal arteritis. Among neuromuscular emergencies, watch a myasthenic crisis or Guillain-Barré syndrome for respiratory muscle weakness — declining vital capacity, not oxygen saturation, is the early warning.

Gastrointestinal Emergencies

Gastrointestinal is 14 scored questions in the July 2026 outline, newly split from the old combined GI/GU area.^[2] The high-yield emergencies are GI bleeding and the surgical acute abdomen.

GI Bleeding & Esophageal Varices

An upper GI bleed shows hematemesis (vomiting blood or coffee-ground material) or melena (black, tarry stools); a lower bleed shows bright-red rectal bleeding. Priorities are airway protection, two large-bore IVs, and fluid then blood resuscitation, with early endoscopy.

Bleeding esophageal varices in a cirrhotic patient carry high mortality and may need vasoactive drugs (octreotide), antibiotics, and banding. Tachycardia and a narrowing pulse pressure are early signs of blood loss; hypotension is a late sign.

The Acute Abdomen

A rigid, board-like abdomen with rebound tenderness signals peritonitis — a surgical emergency. Localize the pain: right-lower-quadrant pain with rebound at McBurney’s point suggests appendicitis; right-upper-quadrant pain after fatty food with a positive Murphy’s sign suggests cholecystitis; distension with vomiting and absent stool suggests bowel obstruction. Keep the patient NPO, give IV fluids and analgesia, and arrange imaging and surgical evaluation.

Pancreatitis & Liver Failure

Acute pancreatitis (severe epigastric pain radiating to the back, vomiting, elevated lipase) is treated with aggressive IV fluids, pain control, and NPO status; watch for the systemic complications of severe disease. In liver failure, hepatic encephalopathy (confusion, asterixis) is driven by ammonia and treated with lactulose, and a tense, fluid-filled abdomen raises the risk of spontaneous bacterial peritonitis.

Genitourinary, Gynecology & Obstetrical Emergencies

This area is 10 scored questions in the July 2026 outline (renal failure moved here from Medical).^[2] The flagship emergencies are obstetric bleeding and the surgical torsions.

Obstetric Emergencies

An ectopic pregnancy (amenorrhea, unilateral pelvic pain, vaginal bleeding) can rupture into hemorrhagic shock — a surgical emergency. Distinguish the third-trimester bleeds: abruptio placenta is painful bleeding with a rigid uterus, while placenta previa is painless bright-red bleeding (no vaginal exam). Severe preeclampsia, eclampsia, and HELLP syndrome are treated with magnesium sulfate for seizure prophylaxis and blood-pressure control; postpartum hemorrhage (most often uterine atony) is managed with fundal massage and uterotonics.

Gynecologic Emergencies & Sexual Assault

Ovarian torsion causes sudden severe unilateral pelvic pain and is a surgical emergency. For a sexual-assault patient, the priorities are safety, medical care, trauma-informed support, and careful forensic evidence collection with chain of custodyby a trained examiner (a SANE where available), with the patient’s consent.

Genitourinary & Renal Emergencies

Testicular torsion is a true emergency — sudden severe scrotal pain with a high-riding testis and an absent cremasteric reflex needs immediate urology, because the testis can be lost within hours. Renal calculi cause severe colicky flank pain radiating to the groin with hematuria. Acute renal failure can cause life-threatening hyperkalemia — watch for peaked T waves and a widening QRS, and treat with calcium (cardioprotection), insulin and glucose, and measures to remove potassium.

Mental Health Emergencies

Mental Health is 13 scored questions and was reorganized in the July 2026 outline to add bipolar, psychotic, and depressive disorders explicitly.^[2] The unifying priority is safety — of the patient and of the staff.

Suicide Risk & Patient Safety

For a suicidal patient, ensure continuous observation, remove items that could be used for self-harm, and assess risk directly — asking about suicidal thoughts does not plant the idea. A specific plan, the means, and the intent raise the risk.

Document the assessment, ensure a mental-health evaluation, and never leave a high-risk patient unobserved. Also screen for the medical mimics of psychiatric presentations (hypoglycemia, hypoxia, infection, toxic ingestion) — “medical clearance” before psychiatric disposition is a recurring theme.

Agitation, Psychosis & De-escalation

For an agitated or violent patient, verbal de-escalation comes first: a calm voice, clear limits, personal space, and removing triggers. If the patient remains a danger to self or others, chemical sedation and, as a last resort, physical restraint may be used within strict legal and ethical limits, with close monitoring of airway, circulation, and skin while restrained. Acute psychosis, mania, and severe depression are managed with safety, support, and psychiatric involvement.

Medical Emergencies

Medical is 15 scored questionsand is the broad “everything else” area — sepsis, anaphylaxis, endocrine and electrolyte crises, hematologic emergencies, and substance withdrawal.^[2] It is where the systemic, time-critical conditions live.

Sepsis, Anaphylaxis & Shock

Sepsis is organ dysfunction from a dysregulated response to infection; septic shock adds persistent hypotension needing vasopressors plus a high lactate. The early bundle: measure lactate, draw blood cultures before antibiotics, give broad-spectrum antibiotics fast, and give a 30 mL/kg crystalloid bolus for hypotension or a high lactate. Anaphylaxis is the rapid, systemic allergic reaction whose first-line treatment is intramuscular epinephrine — given immediately, not after antihistamines.

Endocrine & Electrolyte Emergencies

DKA (high glucose, anion-gap acidosis, ketones, Kussmaul breathing) is treated with fluids first, then an insulin infusion, with careful potassium replacement — insulin drives potassium into cells, so do not start it if the potassium is low until it is corrected. HHS has even higher glucose with minimal ketosis. Thyroid storm (fever, tachycardia, altered mental status) and adrenal crisis are life-threatening endocrine emergencies, and hypoglycemia is reversed with IV dextrose.

Hematologic & Substance-Related Emergencies

A sickle cell vaso-occlusive crisis needs aggressive analgesia, hydration, oxygen, and a search for triggers like infection. DIC causes simultaneous clotting and bleeding and is treated by addressing the underlying cause and replacing products.

The immunocompromised patient with neutropenic fever needs urgent broad-spectrum antibiotics. For substance use, recognize withdrawal — alcohol withdrawal (tremor, tachycardia, and the risk of seizures and delirium tremens) is scored with CIWA and treated with benzodiazepines; opioid overdose is reversed with naloxone.

Musculoskeletal and Wound Emergencies

Musculoskeletal and Wound is 11 scored questions, but it holds limb- and life-threatening emergencies.^[2]

Compartment Syndrome & Fractures

Compartment syndrome is the limb-threatening emergency: rising pressure in a closed compartment recognized by the 6 P’s, where pain out of proportion and on passive stretch is the earliest sign and pulselessness and paralysis are late. Treatment is emergent fasciotomy; do not elevate above the heart or apply ice, and remove any constricting cast. For fractures, assess neurovascular status before and after splinting; an open fracture needs early antibiotics and tetanus prophylaxis, and long-bone fractures can cause fat embolism.

Amputations & Hemorrhage Control

Control life-threatening extremity bleeding with direct pressure, then a tourniquet (note the time applied). For a traumatic amputation, control hemorrhage first, then preserve the amputated part for possible replantation: wrap it in saline-moistened gauze, seal it in a bag, and place that bag on ice — do not let the part freeze or sit directly on ice. A crush injury can cause rhabdomyolysis and acute kidney injury, treated with aggressive IV fluids.

Wounds, Tetanus & Infection

Irrigate and assess wounds for depth, foreign bodies, and neurovascular or tendon involvement; update tetanus prophylaxis based on wound type and immunization history. Never remove an impaled object — stabilize it in place. Watch for the rare but rapidly fatal necrotizing soft-tissue infection (pain out of proportion, crepitus, systemic toxicity), which is a surgical emergency.

Head, Eye, Ear, Nose, Throat Emergencies

HEENT is 10 scored questionsin the July 2026 outline (expanded from the old “Maxillofacial and Ocular” area).^[2] It centers on the vision- and airway-threatening emergencies.

Ocular Emergencies

The sight-threatening emergencies are time-critical. A chemical eye burn needs immediate, copious irrigation before anything else. Acute angle-closure glaucoma (severe eye pain, halos, a mid-dilated fixed pupil, nausea) needs urgent pressure-lowering.

Central retinal artery occlusion is sudden, painless monocular vision loss. A ruptured globe is shielded — not pressed — and a hyphema (blood in the anterior chamber) needs upright positioning and ophthalmology.

Ear, Nose & Throat Emergencies

Most epistaxis is anterior and controlled with direct pressure (lean forward, pinch the soft nose) and packing; a posterior bleed can be heavy and compromise the airway. Epiglottitis (high fever, drooling, a tripod position, stridor) and a peritonsillar abscess are airway emergencies — keep the patient calm, avoid agitating the throat, and prepare for a difficult airway.

Maxillofacial & Dental Emergencies

Maxillofacial trauma threatens the airway first — blood, broken teeth, and edema can obstruct rapidly, so be ready for a difficult airway. Ludwig’s angina (a rapidly spreading floor-of-mouth infection) is an airway emergency. An avulsed permanent tooth should be handled by the crown, gently rinsed, and reimplanted or stored in milk or saliva to preserve it.

Environment, Toxicology & Communicable Diseases

This combined area is 13 scored questions — environmental injury, poisoning, and communicable-disease control.^[2]

Burns, Temperature & Environmental Injury

In a major burn, the first priority is the airway: suspect inhalation injury with facial burns, singed nasal hairs, soot, or hoarseness, and intubate early before edema closes the airway. Estimate size with the Rule of Nines and calculate fluids with the Parkland formula.

Heat stroke (high core temperature with altered mental status) needs rapid cooling; hypothermia and frostbite need gradual rewarming and gentle handling (a cold heart is irritable). For carbon monoxide poisoning, remember that pulse oximetry can read falsely normal — give high-flow oxygen.

Toxicology, Toxidromes & Antidotes

Identify the poison by its toxidrome: cholinergic (the SLUDGE secretions, treated with atropine and pralidoxime for organophosphates), anticholinergic (“hot, red, dry, and mad”), opioid (pinpoint pupils and slow breathing, reversed with naloxone), and sympathomimetic (agitation, hypertension). Care is supportive first; specific antidotes include N-acetylcysteine for acetaminophen, naloxone for opioids, and sodium bicarbonate for tricyclic overdose.

Communicable Diseases & Isolation

Beyond standard precautions, match the precaution to the route: contact (gown and gloves — C. difficile, MRSA), droplet (a surgical mask — influenza, pertussis, meningococcus), and airborne (an N95 in a negative-pressure room — tuberculosis, measles, varicella). Remember that C. difficile requires soap-and-water handwashing because alcohol gel does not kill its spores. Early identification and isolation protect everyone in a crowded ED.^[8]

Professional Issues

Professional Issues is 12 scored questions, reorganized in the July 2026 outline into prioritization (triage, mass casualty, throughput) and legal/ethical issues.^[2] It is reliable points if you know the frameworks.

Triage, ESI & Mass Casualty

Day-to-day ED triage uses the five-level ESI (see the algorithm above): acuity first, then resource count, with danger-zone vitals up-triaging a would-be Level 3 to Level 2. In a mass-casualty incident the goal flips from doing the most for each patient to doing the most good for the most people; START triage sorts adults in under a minute using respirations, perfusion, and mental status into immediate (red), delayed (yellow), minor (green), and expectant/deceased (black).

EMTALA, Consent & Legal Issues

EMTALA requires a medical screening exam and stabilization for anyone who presents to the ED, regardless of ability to pay, and governs appropriate transfers. Respect informed consent and autonomy; a competent adult may refuse care, while a true emergency in a patient who cannot consent proceeds under implied consent. Protect privacy under HIPAA, and know the rules around minors and emergency treatment.

Forensics, Abuse Reporting & Ethics

Preserve forensic evidence and chain of custody (document wounds objectively, handle clothing and bullets carefully). Recognizing and reporting suspected abuse or neglect — of children, older adults, and vulnerable patients — is a mandatory duty. Support end-of-life and palliative care, honor advance directives, practice cultural humility, and address workplace violence and the impaired colleague within professional and legal standards.

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. Cardiovascular (18), Respiratory (17), and Neurological (17) are about a third of the exam — start there, then Medical (15) and GI (14).
• Anchor everything to prioritization. Airway, breathing, and circulation come first; most clinical questions reward the first, safest action that protects perfusion and oxygenation.
• Master the recognition patterns. STEMI on the 12-lead, tension pneumothorax, Beck’s triad, the four shock states, BE-FAST, sepsis, and anaphylaxis appear again and again.
• Learn ESI triage cold. A dying patient is ESI 1, a high-risk or severely distressed patient is ESI 2, then sort by resource count — and remember the danger-zone vitals.
• Don’t skip the smaller areas. Mental Health, HEENT, GU/Gyn/OB, and Professional Issues are reliable points if you know the patterns and the law.

Common questions CEN candidates search and get asked — each answered briefly and backed by an official source (BCEN, AHRQ, AHA/ACLS, CDC, or NIH). Tap any card to test yourself.

CEN Glossary

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

CEN

Certified Emergency Nurse — the BCEN specialty certification validating the broad knowledge a registered nurse needs to care for emergency-department patients across all presentations.

BCEN

Board of Certification for Emergency Nursing — the organization that owns and administers the CEN, CPEN, CFRN/CTRN, and TCRN credentials.

ESI

Emergency Severity Index — a five-level emergency-department triage algorithm that sorts patients first by acuity (need for a life-saving intervention or high risk) and then by anticipated resource use.

triage

The rapid sorting of patients by acuity so the sickest are seen first; in the ED this is most often done with the five-level ESI.

START

Simple Triage And Rapid Treatment — a mass-casualty triage system using respirations, perfusion, and mental status to sort patients into immediate (red), delayed (yellow), minor (green), and expectant/deceased (black).

EMTALA

Emergency Medical Treatment and Active Labor Act — the federal law requiring a medical screening exam and stabilization of any patient who presents to the ED, regardless of ability to pay.

ACS

Acute coronary syndrome — the spectrum of unstable angina, NSTEMI, and STEMI caused by reduced coronary blood flow.

STEMI

ST-elevation myocardial infarction — a full-thickness infarct shown by ST elevation on the ECG that needs emergent reperfusion (PCI or fibrinolytics).

Beck's triad

The three classic signs of cardiac tamponade: hypotension, jugular venous distension, and muffled or distant heart sounds.

pulsus paradoxus

A fall in systolic blood pressure of more than 10 mmHg on inspiration; a sign of cardiac tamponade and of severe asthma.

Cushing's triad

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

GCS

Glasgow Coma Scale — a 3-to-15 score of consciousness across eye opening (1–4), verbal response (1–5), and best motor response (1–6); 8 or below is severe impairment.

ICP

Intracranial pressure — normally about 5–15 mmHg; sustained elevation reduces cerebral perfusion and is an emergency.

NIHSS

National Institutes of Health Stroke Scale — a standardized score that quantifies the severity of a stroke's neurologic deficit.

tPA

Tissue plasminogen activator (e.g., alteplase or tenecteplase) — a clot-busting thrombolytic given to eligible ischemic-stroke patients within the time window.

tension pneumothorax

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

PE

Pulmonary embolism — a thrombus lodged in the pulmonary circulation causing sudden dyspnea, pleuritic pain, tachycardia, and hypoxia, often with clear lungs.

ARDS

Acute respiratory distress syndrome — non-cardiogenic pulmonary edema with bilateral infiltrates and refractory hypoxemia, managed with lung-protective ventilation.

RSI

Rapid sequence intubation — giving a sedative and a paralytic together to rapidly secure an emergency airway.

capnography

Continuous monitoring of exhaled (end-tidal) carbon dioxide; confirms airway placement, tracks perfusion, and helps detect return of circulation.

sepsis

Life-threatening organ dysfunction caused by a dysregulated body response to infection.

septic shock

Sepsis with persistent hypotension requiring vasopressors to keep the mean arterial pressure ≥65 mmHg, plus a lactate over 2 mmol/L despite adequate fluids.

lactate

A blood marker of inadequate tissue perfusion; a key value in sepsis bundles that should fall with effective resuscitation.

anaphylaxis

A severe, rapid-onset systemic allergic reaction; the first-line treatment is intramuscular epinephrine.

DKA

Diabetic ketoacidosis — high glucose with an anion-gap metabolic acidosis and ketones, treated with IV fluids, insulin, and careful potassium replacement.

HHS

Hyperosmolar hyperglycemic state — extreme hyperglycemia with profound dehydration and minimal ketosis or acidosis.

thyroid storm

A life-threatening hyperthyroid crisis with high fever, tachycardia, and altered mental status.

DIC

Disseminated intravascular coagulation — widespread clotting that consumes clotting factors and platelets, causing simultaneous clotting and bleeding.

compartment syndrome

Rising pressure within a closed fascial compartment that cuts off perfusion; the 6 P's (pain, paresthesia, pallor, pulselessness, paralysis, poikilothermia) — a fasciotomy emergency.

rhabdomyolysis

Muscle breakdown that releases myoglobin (e.g., after a crush injury) and can cause acute kidney injury; marked by elevated CK and dark urine.

cardiogenic shock

Shock from pump failure (a large MI, arrhythmia, or cardiomyopathy) producing cold, clammy skin and pulmonary edema.

distributive shock

Shock from widespread vasodilation — septic, anaphylactic, or neurogenic.

neurogenic shock

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

hypovolemic shock

Shock from volume loss (hemorrhage, GI bleed, dehydration) marked by tachycardia, a narrow pulse pressure, and cool skin.

obstructive shock

Shock from a mechanical block to cardiac filling or output — tension pneumothorax, cardiac tamponade, or massive pulmonary embolism.

Rule of Nines

A method to estimate burn total body surface area in adults: head 9%, each arm 9%, each leg 18%, anterior trunk 18%, posterior trunk 18%, perineum 1%.

Parkland formula

A burn fluid estimate: 4 mL lactated Ringer's × weight (kg) × %TBSA, half in the first 8 hours from the burn, the rest over 16 hours; titrate to urine output.

toxidrome

A recognizable cluster of signs and symptoms produced by a class of poison (e.g., cholinergic, anticholinergic, opioid, sympathomimetic), used to identify the agent.

CIWA

Clinical Institute Withdrawal Assessment for Alcohol — a scored tool that guides symptom-triggered treatment of alcohol withdrawal.

status epilepticus

A seizure lasting more than 5 minutes, or repeated seizures without recovery of consciousness; a benzodiazepine is first-line treatment.

ectopic pregnancy

A pregnancy implanted outside the uterus (usually a fallopian tube); rupture causes hemorrhagic shock and is a surgical emergency.

HELLP

A severe variant of preeclampsia — Hemolysis, Elevated Liver enzymes, and Low Platelets.

abruptio placenta

Premature separation of the placenta from the uterine wall, classically causing painful vaginal bleeding and a rigid uterus.

placenta previa

A placenta covering the cervical os, classically causing painless, bright-red vaginal bleeding in later pregnancy.

CRAO

Central retinal artery occlusion — sudden, painless loss of vision in one eye; a time-critical ocular emergency.

hyphema

Blood pooled in the anterior chamber of the eye, usually after blunt trauma.

ROSC

Return of spontaneous circulation — the restoration of a pulse after cardiac arrest.

acute angle-closure glaucoma

A sudden rise in intraocular pressure causing severe eye pain, a red eye, halos around lights, and a mid-dilated fixed pupil; an emergency that can blind within hours.

CEN Study Guide FAQ

References

1. 1.Board of Certification for Emergency Nursing. “Certified Emergency Nurse (CEN).” BCEN. ↑
2. 2.Board of Certification for Emergency Nursing. “CEN Examination Content Outline (effective July 2026).” BCEN. ↑
3. 3.Board of Certification for Emergency Nursing. “FAQs About the CEN Exam.” BCEN. ↑
4. 4.Board of Certification for Emergency Nursing. “The CEN Certification Process & Eligibility.” BCEN. ↑
5. 5.Board of Certification for Emergency Nursing. “BCEN Recertification.” BCEN. ↑
6. 6.Agency for Healthcare Research and Quality (AHRQ). “Emergency Severity Index (ESI): A Triage Tool for Emergency Departments.” AHRQ. ↑
7. 7.American Heart Association. “Advanced Cardiovascular Life Support (ACLS) Algorithms.” AHA / cpr.heart.org. ↑
8. 8.Centers for Disease Control and Prevention (CDC). “Infection Control & Isolation Precautions.” CDC. ↑
9. 9.National Institutes of Health / National Library of Medicine. “StatPearls & MedlinePlus Clinical Reference (emergency topics).” NIH/NLM. ↑

Career Employer

Career Employer is the ultimate resource to help you get started working the job of your dreams. We cover topics from general career information, career searching, exam preparation with free study materials, career interviewing, and becoming successful in your career of choice.

Follow Us:

All Posts