Cardiac Arrest

Cardiac Arrest as a High-Yield Clinical Priority

Cardiac arrest is the abrupt loss of heart function, leading to cessation of blood flow to vital organs. In the emergency department (ED), it represents a true time-critical event where every second directly impacts survival and neurological outcome.[1] For the Certified Emergency Nurse (CEN) exam, mastery of cardiac arrest recognition, high-quality cardiopulmonary resuscitation (CPR), advanced cardiac life support (ACLS) algorithms, and post-resuscitation care is essential. This topic consistently appears as a high-yield section on the CEN blueprint.

Essential Terminology for Arrest Rhythms and Interventions

  • Cardiac Arrest: Cessation of cardiac mechanical activity, confirmed by unresponsiveness, absent breathing, and no palpable pulse.[2]
  • Return of Spontaneous Circulation (ROSC): Restoration of a palpable pulse and measurable blood pressure.[1]
  • Defibrillation: Delivery of a therapeutic dose of electrical energy to the heart to terminate ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT).[3]
  • Shockable Rhythm: VF and pulseless VT are the only rhythms treated with defibrillation.[1]
  • Non-Shockable Rhythm: Asystole and pulseless electrical activity (PEA) are not treated with defibrillation; the focus is on high-quality CPR and identifying reversible causes.[1]
  • High-Quality CPR: Chest compressions at a rate of 100–120/min, depth of at least 2 inches (5 cm), full chest recoil, minimizing interruptions, and avoiding excessive ventilation.[1]

The AHA Chain of Survival and ACLS Protocol

The Chain of Survival (AHA)

  1. Immediate recognition and activation of the emergency response system — verify unresponsiveness, call for help, activate code team.
  2. Early high-quality CPR — compressions first, ratio 30:2, with minimal interruptions.
  3. Rapid defibrillation — apply AED or manual defibrillator as soon as a shockable rhythm is identified.
  4. Advanced life support — secure airway (ETT or supraglottic device), IV/IO access, administer medications.
  5. Post–cardiac arrest care — targeted temperature management (TTM), hemodynamic optimization, and PCI for STEMI.[1]

ACLS Pulseless Arrest Algorithm (Adult)[1]

  • Start CPR — give oxygen, attach monitor/defibrillator.
  • Check rhythm:
    • Shockable (VF/pVT): Defibrillate → immediately resume CPR for 2 minutes → check rhythm; repeat every 2 minutes. During CPR, establish IV/IO access. Give epinephrine 1 mg every 3–5 minutes. Consider amiodarone or lidocaine for refractory VF/pVT.
    • Non-shockable (Asystole/PEA): Continue CPR for 2 minutes → check rhythm. Gain IV/IO access. Give epinephrine 1 mg as soon as possible, repeat q3–5min. Identify and treat reversible causes (Hs and Ts).
  • Reversible Causes (Hs & Ts):
    • Hypovolemia, Hypoxia, Hydrogen ion (acidosis), Hypo-/Hyperkalemia, Hypothermia, Tension pneumothorax, Tamponade (cardiac), Toxins, Thrombosis (pulmonary or coronary).[2]

Recognizing Cardiac Arrest: Clinical Presentation

  • Unresponsiveness — no response to voice or tactile stimuli.
  • Agonal breathing — gasping, irregular, ineffective respirations may be present in the first minutes.
  • Absence of pulse — palpate carotid (or femoral) for no more than 10 seconds.
  • Loss of consciousness — occurs within seconds of arrest.
  • Cyanosis — due to lack of oxygenated blood.
  • Seizure-like activity — may mimic seizure but is secondary to cerebral hypoxia.

Bedside Diagnostics in Cardiac Resuscitation

  • Primary Survey (A-B-C-D-E): Assess airway patency, breathing (chest rise, breath sounds), circulation (pulse check, skin color), disability (neurologic status), and exposure.
  • Cardiac Monitoring: Attach defibrillator pads and five-lead ECG to identify rhythm.
  • End-Tidal CO₂ (ETCO₂) Monitoring: Waveform capnography confirms ETT placement and monitors CPR quality (goal ETCO₂ > 10 mmHg; a sudden rise may indicate ROSC).[1]
  • Point-of-Care Ultrasound (POCUS): Can assess for cardiac tamponade, pneumothorax, hypovolemia, and cardiac activity (to differentiate PEA from true asystole).[4]
  • Arterial Blood Gas (ABG): Measures pH, PaO₂, PaCO₂, lactate — guides ventilation and identifies acidosis.
  • Laboratory Studies: Electrolytes (K⁺, Ca⁺⁺, Mg⁺⁺), troponin, glucose, and tox screen if indicated.

Therapeutic Steps in Cardiac Arrest Management

Initial Actions

  • High-quality CPR — rate 100–120/min, depth ≥2 in., allow full chest recoil, limit interruptions to <10 seconds for rhythm checks.[1]
  • Defibrillation (if shockable) — use biphasic energy: 120–200 J (follow manufacturer recommendations); if monophasic, 360 J. Resume CPR immediately after each shock.

Airway and Ventilation

  • Bag-mask ventilation (30:2 ratio) until advanced airway placed.
  • Advanced airway (ETT or supraglottic): confirm placement with waveform capnography. Then ventilate once every 6 seconds (10 breaths/min) without pausing compressions.[1]

Medications

  • Epinephrine: 1 mg IV/IO q3–5 min. First dose given as soon as IV access obtained in non-shockable rhythms; in shockable rhythms, give after second defibrillation.[1]
  • Amiodarone: First dose 300 mg IV/IO push, second dose 150 mg IV/IO for refractory VF/pVT.[1]
  • Lidocaine: Alternative (1–1.5 mg/kg first dose; 0.5–0.75 mg/kg second dose) if amiodarone is unavailable.
  • Magnesium Sulfate: 1–2 g IV only for torsades de pointes or suspected hypomagnesemia.[1]

Reversible Cause Management

  • Hypovolemia: Rapid fluid resuscitation with isotonic crystalloids.
  • Hypoxia: Ensure adequate oxygenation and ventilation, secure airway.
  • Acidosis: Optimize ventilation and compressions; consider sodium bicarbonate only in specific conditions (e.g., tricyclic overdose, hyperkalemia).[1]
  • Tension pneumothorax: Needle decompression (14-gauge, second intercostal space, midclavicular line).
  • Cardiac tamponade: Pericardiocentesis.
  • Thrombosis (MI): Consider fibrinolytic therapy or emergent PCI if ROSC achieved.
  • Toxin: Administer appropriate antidote (e.g., naloxone for opioid overdose).

Post–Cardiac Arrest Care

  • Targeted temperature management (TTM) — maintain core temperature 32–36°C for at least 24 hours in patients who remain comatose after ROSC.[1]
  • Hemodynamic support – goal mean arterial pressure (MAP) ≥65 mmHg with fluids, vasopressors (norepinephrine first line).[1]
  • PCI evaluation – urgent cardiac catheterization for suspected STEMI or new LBBB on ECG.[5]
  • Neurologic prognostication – avoid sedation interruptions for 72 hours if TTM used; use clinical exam, EEG, and neuroimaging.

Minimizing Risks During Cardiac Arrest Management

  • Inadequate CPR – failure to achieve adequate depth or recoil reduces coronary and cerebral perfusion.
  • Excessive ventilation – increases intrathoracic pressure, decreases venous return, and lowers cardiac output.[1]
  • Defibrillator safety – ensure all personnel are “clear” before shock delivery; no contact with patient or stretcher.
  • Medication errors – use closed-loop communication; verify IV/IO patency; avoid giving epinephrine before defibrillation in shockable rhythms (unless already delayed).
  • Unrecognized ROSC – if pulse returns but CPR continues, risk of injury; monitor ETCO₂ and adjunct pulse checks.
  • Post-arrest hypotension – aggressive correction to avoid secondary brain injury.
  • Hypoglycemia/hyperglycemia – monitor blood glucose; treat hypoglycemia (D50), avoid severe hyperglycemia (>180 mg/dL).

Exam-Focused Strategies for Cardiac Arrest

  • Memorize the Hs and Ts — a common CEN question asks you to identify a reversible cause (e.g., chest pain + cardiac arrest → suspect MI; trauma + arrest → consider tension pneumothorax or tamponade).
  • Remember the “2-minute rule”: After each defibrillation or rhythm check, resume CPR for 2 minutes before checking again.
  • Know the correct energy doses: Biphasic 120–200 J (follow manufacturer label); monophasic 360 J.
  • Amiodarone vs. Lidocaine: Amiodarone is first-line for refractory VF/pVT; lidocaine is an alternative if amiodarone is not available.
  • Epinephrine timing: In shockable rhythms, give after the second shock; in non-shockable, give ASAP.
  • Airway management tip: Once an advanced airway is placed, ventilate at 10 breaths/min without pausing compressions — do not hyperventilate.
  • TTM indication: Comatose patients after ROSC (no purposeful movement). Do not apply to awake patients.
  • Common pitfall: Confirming cardiac arrest by pulse check >10 seconds — this delays CPR. The CEN exam emphasizes minimal interruption.
  • Memory aid: Use “Shock When Shockable, EPI Every 3–5, Hs & Ts Always” for algorithm flow.

References & Sources

  1. Panchal AR, Berg KM, Hirsch KG, et al. 2019 American Heart Association Focused Update on Adult Advanced Cardiovascular Life Support: An Update to the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2019;140(24):e881–e894. https://doi.org/10.1161/CIR.0000000000000732
  2. Lewis SL, Bucher L, Heitkemper MM, Harding MM. Medical-Surgical Nursing: Assessment and Management of Clinical Problems. 10th ed. St. Louis, MO: Elsevier; 2017. https://www.elsevier.com/books/medical-surgical-nursing/lewis/978-0-323-32852-4
  3. Lee SM, Kim HL, Kim MA. Defibrillation. Korean J Anesthesiol. 2013;64(5):397-402. https://doi.org/10.4097/kjae.2013.64.5.397
  4. Zücker AR, Blehar DJ, Guirgis FW, Nelson MJ, Borde AB. Point-of-care ultrasound use during cardiac arrest: a retrospective review. Am J Emerg Med. 2018;36(10):1831-1835. https://doi.org/10.1016/j.ajem.2018.02.007
  5. O’Gara PT, Kushner FG, Ascheim DD, et al. 2013 ACCF/AHA guideline for the management of ST-elevation myocardial infarction: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation. 2013;127(4):e362-e425. https://doi.org/10.1161/CIR.0b013e3182742cf6

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