What is the recommended protocol for diagnosing and managing cardiac arrest, including initial assessment, high‑quality CPR, defibrillation, medication administration, airway management, treatment of reversible causes, and post‑cardiac arrest care?

Cardiac Arrest Diagnosis and Management Protocol

Immediately initiate high-quality CPR with chest compressions at 100-120/min and depth of at least 2 inches (5 cm) upon recognizing cardiac arrest, minimize interruptions to maintain chest compression fraction >80%, and deliver early defibrillation for shockable rhythms while simultaneously addressing reversible causes. 1, 2, 3

Initial Assessment and Recognition

Check for responsiveness by tapping the victim's shoulder and shouting "Are you all right?" 3

• Simultaneously assess breathing and pulse within 10 seconds, looking specifically for absent breathing or only gasping while palpating for a definite pulse 1, 3
• If unresponsive with no breathing or only gasping, immediately activate the emergency response system and retrieve the AED and emergency equipment 1, 3
• In the current era of mobile devices, both EMS activation and CPR initiation should occur simultaneously 1

High-Quality CPR: The Foundation of Survival

Begin chest compressions immediately without removing clothing first, as this is the most critical intervention 1

Compression Technique

• Rate: 100-120 compressions per minute (frequencies below 100/min decrease ROSC; above 120/min reduces coronary blood flow) 1, 2, 3
• Depth: At least 2 inches (5 cm) in adults, essential for generating critical blood flow to heart and brain 1, 2, 3
• Allow complete chest recoil after each compression to permit the heart to fill completely; incomplete recoil significantly reduces coronary perfusion pressure 1, 2, 3
• **Minimize interruptions to <10 seconds**, maintaining chest compression fraction >80% to maximize perfusion and survival 1, 2, 3
• Change compressor every 2 minutes or sooner if fatigued to maintain quality 1, 3

Ventilation Strategy

• Perform 30 compressions to 2 breaths until an advanced airway is placed 1, 3
• Avoid excessive ventilation, which reduces venous return and cardiac output 1, 2
• Compression-only CPR is appropriate if rescuers are untrained or unwilling to provide respirations 1

Rhythm Assessment and Defibrillation

Check rhythm as soon as monitor/defibrillator is available 1

For Shockable Rhythms (VF/pVT)

• Deliver 1 shock immediately when VF/pVT is identified, as early defibrillation is the single most effective intervention 1, 3, 4, 5
• Shock energy: Biphasic 120-200 Joules initially (use manufacturer recommendation; if unknown, use maximum available); Monophasic 360 Joules 1
• Resume CPR immediately for 2 minutes after the shock without pausing to check rhythm, starting with chest compressions 1, 3
• Patients with VF have significantly higher ROSC rates (55.43%) compared to asystole (24.05%) 4

For Non-Shockable Rhythms (Asystole/PEA)

• Resume CPR immediately for 2 minutes 1
• Focus on identifying and treating reversible causes 1, 6

Medication Administration

Establish IV/IO access during CPR without interrupting compressions 1, 3

Epinephrine

• Administer 1 mg IV/IO every 3-5 minutes throughout the resuscitation 1, 3
• For pediatric patients: 0.01 mg/kg (0.1 mL/kg of 0.1 mg/mL concentration); maximum 1 mg 1

Antiarrhythmics for Refractory VF/pVT

• Amiodarone: First dose 300 mg IV/IO bolus; second dose 150 mg 1, 3
  • Pediatric: 5 mg/kg bolus; may repeat up to 3 total doses 1
• Lidocaine (alternative): First dose 1-1.5 mg/kg; second dose 0.5-0.75 mg/kg 1, 3
  • Pediatric: Initial 1 mg/kg loading dose 1

Advanced Airway Management

Place endotracheal tube or supraglottic airway when feasible without prolonged interruption of compressions 1, 3, 4

• Confirm placement with waveform capnography, the gold standard for tube verification 1, 3
• ETCO₂ <10 mmHg suggests inadequate CPR quality and should prompt reassessment of compression technique 3
• Once advanced airway is placed, provide continuous chest compressions with 1 breath every 6 seconds (10 breaths/min) 1, 2, 3
• For pediatric patients without advanced airway: 15:2 compression-ventilation ratio with 2 rescuers 1

Critical pitfall: Delays in ventilation are common in hospital settings, with only 37% of arrests receiving ventilation within 1 minute; mouth-to-mask resuscitation achieves faster ventilation times than bag-valve-mask 7

Treatment of Reversible Causes: The H's and T's

Systematically address potentially reversible causes during resuscitation 1, 6

The 4 H's

• Hypovolemia: Administer fluid boluses 1, 6
• Hypoxia: Ensure adequate oxygenation and ventilation 1, 6
• Hydrogen ion (acidosis): Consider sodium bicarbonate for severe metabolic acidosis 1, 6
• Hypo-/Hyperkalemia: Treat electrolyte abnormalities aggressively 1, 6
• Hypothermia: Rewarm if core temperature is low 1, 6

The 4 T's

• Tension pneumothorax: Needle decompression followed by chest tube 1, 6
• Tamponade (cardiac): Pericardiocentesis 1, 6
• Toxins: Administer specific antidotes (e.g., naloxone for opioids) 1, 6
• Thrombosis (pulmonary): Consider thrombolytics or ECPR 1, 6
• Thrombosis (coronary): Prepare for emergent cardiac catheterization 1, 6

Point-of-care ultrasound has a critical role in identifying reversible causes such as tamponade, tension pneumothorax, and pulmonary embolism 6

Recognition of Return of Spontaneous Circulation (ROSC)

Monitor for signs of ROSC during rhythm checks 1, 3

• Palpable pulse and measurable blood pressure 1, 3
• Abrupt sustained increase in ETCO₂ (typically ≥40 mmHg), the most reliable indicator during ongoing CPR 1, 3
• Spontaneous arterial pressure waves with intra-arterial monitoring 1, 3

Post-Cardiac Arrest Care

Immediately transition to comprehensive post-resuscitation management upon achieving ROSC 3, 8

Oxygenation and Ventilation

• Target SpO₂ 94-98% to avoid both hypoxemia and hyperoxemia, which worsen neurological outcomes 3
• Maintain normocapnia by adjusting ventilation parameters 3

Hemodynamic Support

• Maintain MAP ≥65 mmHg with vasopressors (norepinephrine or epinephrine) as needed 3
• Identify and treat underlying cause of arrest 3, 8

Cardiac Evaluation

• Obtain 12-lead ECG immediately to identify ST-elevation MI 3
• Consider urgent coronary angiography for suspected cardiac etiology, particularly with ST-elevation or high suspicion for coronary thrombosis 3

Neuroprotection

• Initiate targeted temperature management for all patients who don't follow commands after ROSC, maintaining temperature between 32-36°C for at least 24 hours 3
• Avoid premature withdrawal of care; prognostication requires a multifaceted approach considering potential for neurological recovery and should not occur in the absence of definite prognostic signs 8

Quality Improvement

• In-hospital cardiac arrest affects over 290,000 adults annually in the United States with mean age 66 years, 58% male, and 81% presenting with non-shockable rhythms 8
• Hospitals should participate in national quality-improvement initiatives to optimize outcomes 8
• The "chain of survival" concept emphasizes that successful resuscitation depends on rapid delivery of all critical interventions, with early defibrillation being the single most effective intervention capable of achieving 30% long-term survival for witnessed VF 5