What is the step‑by‑step management of an adult cardiac arrest, including high‑quality cardiopulmonary resuscitation, defibrillation, epinephrine, amiodarone or lidocaine, treatment of reversible causes (hypoxia, hypovolemia, electrolyte abnormalities, hypothermia, tension pneumothorax, cardiac tamponade, toxins, thrombosis), post‑cardiac‑arrest care (airway and ventilation, hemodynamic support, targeted temperature management, neurological assessment, cardiac evaluation, laboratory work‑up), and considerations for a patient with a history of recurrent seizures?

Management of Adult Cardiac Arrest

Immediately begin high-quality CPR with chest compressions at a depth of at least 2 inches (5 cm) and rate of 100-120/min, minimizing interruptions to less than 10 seconds, and deliver defibrillation for shockable rhythms followed by epinephrine 1 mg IV/IO every 3-5 minutes, while systematically addressing reversible causes (the 5 H's and 5 T's). 1, 2

Initial Response and High-Quality CPR

Ensure scene safety first, then immediately check for responsiveness and activate the emergency response system. 1

Begin CPR immediately without delay:

• Perform chest compressions at a rate of 100-120/min and depth of at least 2 inches (5 cm) 1, 2
• Allow complete chest recoil between compressions 1, 2
• Minimize interruptions in compressions to less than 10 seconds 1, 2
• Avoid excessive ventilation, as it impairs venous return and cardiac output 2
• Change compressor every 2 minutes or sooner if fatigued 1, 2
• Perform cycles of 30 compressions and 2 breaths if trained; compression-only CPR is acceptable for untrained rescuers 1

Rhythm Assessment and Defibrillation

Check rhythm every 2 minutes during CPR cycles. 1

For VF/pulseless VT (shockable rhythms):

• Deliver one shock immediately 1
• Biphasic defibrillator: Use manufacturer recommendation (typically 120-200 Joules initially); if unknown, use maximum available 1
• Monophasic defibrillator: Use 360 Joules 1
• Resume CPR immediately for 2 minutes after shock without pulse check 1
• Recheck rhythm after 2 minutes and repeat cycle 1

For PEA/asystole (non-shockable rhythms):

• Continue CPR and administer epinephrine as soon as feasible 3
• Recheck rhythm every 2 minutes 1

Medication Administration

Establish IV or IO access without delaying CPR. 1, 2, 3

Epinephrine dosing:

• For shockable rhythms: Administer 1 mg IV/IO if initial CPR and defibrillation are unsuccessful 3
• For non-shockable rhythms: Administer 1 mg IV/IO as soon as feasible 3
• Repeat every 3-5 minutes throughout resuscitation 1

Antiarrhythmic therapy for refractory VF/pulseless VT:

• Amiodarone: First dose 300 mg IV/IO bolus, second dose 150 mg IV/IO 1
• Lidocaine (alternative): First dose 1-1.5 mg/kg IV/IO, second dose 0.5-0.75 mg/kg IV/IO 1

Advanced Airway Management

Consider advanced airway placement only after initial CPR cycles or after ROSC. 4

Airway options:

• Endotracheal intubation or supraglottic advanced airway 1
• Use waveform capnography or capnometry to confirm and monitor ET tube placement 1
• Once advanced airway is placed, give 1 breath every 6 seconds (10 breaths/min) with continuous chest compressions 1

Critical pitfall: Do not interrupt chest compressions for more than 10 seconds except for defibrillation. 2

Systematic Treatment of Reversible Causes (5 H's and 5 T's)

The 5 H's:

Hypovolemia:

• Rapidly infuse IV crystalloids or blood products if hemorrhage is suspected 2

Hypoxia:

• Administer 100% oxygen immediately 2
• Place advanced airway and confirm with waveform capnography 2

Hydrogen ion (acidosis):

• Ensure adequate ventilation to eliminate CO2 2
• Consider sodium bicarbonate only for known severe metabolic acidosis or hyperkalemia 2
• Do not routinely administer sodium bicarbonate 3

Hypo-/Hyperkalemia:

• For hyperkalemia: Administer IV calcium chloride or calcium gluconate immediately 2
• For hypokalemia: Correct gradually after ROSC 2
• Never administer IV bolus potassium during cardiac arrest 2

Hypothermia:

• Begin active rewarming measures immediately 2
• Continue resuscitation efforts longer than usual for hypothermic patients 2

The 5 T's:

Tension pneumothorax:

• Perform immediate needle decompression followed by chest tube placement 2

Tamponade (cardiac):

• Perform immediate pericardiocentesis if suspected 2

Toxins:

• Administer specific antidotes if toxin is known 2
• Consider high-dose insulin therapy and IV calcium for calcium channel blocker or beta-blocker toxicity 2
• Beta-blockers may be considered for shock-resistant pVT/VF 3

Thrombosis (pulmonary):

• Consider thrombolytic therapy (alteplase) for suspected massive pulmonary embolism causing cardiac arrest 2, 5

Thrombosis (coronary):

• Prepare for emergency cardiac catheterization and PCI after ROSC 2

Recognition of Return of Spontaneous Circulation (ROSC)

Monitor continuously for signs of ROSC:

• Palpable pulse and measurable blood pressure 1, 2
• Abrupt sustained increase in PETCO2 to ≥40 mm Hg 1, 2
• Spontaneous arterial pressure waves on intra-arterial monitoring 1, 2

Post-Cardiac Arrest Care (After ROSC)

Airway and ventilation:

• Maintain oxygen saturation >95% 2
• Avoid hyperventilation 1, 2
• Confirm advanced airway placement with waveform capnography 1

Hemodynamic support:

• Treat hypotension with vasopressors if needed 2
• Target adequate perfusion pressure 2

Targeted temperature management:

• Initiate therapeutic hypothermia protocols per institutional guidelines 6

Neurological assessment:

• Perform serial neurological examinations 7
• The ultimate goal is return to prior quality and functional state of health 7

Cardiac evaluation:

• Obtain 12-lead ECG 2
• Consider emergency cardiac catheterization for suspected coronary thrombosis 2

Laboratory work-up:

• Obtain arterial blood gas to assess pH, PaCO2, and metabolic derangements 8
• Check electrolytes, particularly potassium 2
• Assess for reversible causes not yet identified 8

Special Considerations for Patients with Recurrent Seizures

For unconscious patients with history of seizures:

• Place in lateral (recovery) position to maintain airway patency and prevent aspiration 8
• Assess airway patency and consider oro- or nasopharyngeal airway if needed 8
• Implement oral hygiene measures and repetitive suctioning of oropharyngeal secretions 8
• Once hemodynamically stable with airway secured, elevate head of bed to 30-45 degrees to reduce aspiration risk 8

Critical Pitfalls to Avoid

• Never delay CPR to establish vascular access or search for reversible causes—CPR comes first 2
• Do not interrupt chest compressions for more than 10 seconds except for defibrillation 2
• Do not administer IV bolus potassium during cardiac arrest for suspected hypokalemia 2
• Do not routinely administer calcium or sodium bicarbonate 3
• Avoid excessive ventilation during CPR 2
• Do not perform pulse checks immediately after defibrillation—resume CPR immediately 6

Termination of Resuscitation

Consider termination after 30 minutes of asystole in patients with end-stage comorbidities and no reversible causes, as the prospect of meaningful recovery is poor. 5