Advanced Cardiovascular Life Support (ACLS) Protocol for Cardiac Arrest
Immediately begin high-quality CPR with chest compressions at least 2 inches deep at 100-120 compressions per minute, minimize all interruptions, and prepare for early defibrillation—these are the most critical interventions that determine survival. 1, 2
Initial Recognition and Response
Check for responsiveness, breathing, and pulse simultaneously within 10 seconds maximum. 1, 2 If no definite pulse is felt, immediately:
- Activate the emergency response system 1
- Retrieve an AED/defibrillator and emergency equipment 1, 2
- Attach cardiac monitor pads as soon as available to identify the arrest rhythm 2
Critical pitfall: Healthcare providers often take too long checking for pulses—if any doubt exists about pulse presence, start compressions immediately rather than delaying. 1
High-Quality CPR Technique
Compression depth: Push hard—at least 2 inches (5 cm) with complete chest recoil between compressions 1, 2, 3
Compression rate: 100-120 compressions per minute continuously 2, 3
Compression-to-ventilation ratio: 30 compressions to 2 breaths until an advanced airway is placed 1, 3
Minimize interruptions: Keep pauses under 10 seconds, particularly during rhythm checks and defibrillation 1, 2
Rotate compressors every 2 minutes to prevent fatigue and maintain compression quality 1, 3
Rhythm-Based Management
For Ventricular Fibrillation (VF) or Pulseless Ventricular Tachycardia (pVT):
Deliver one shock immediately as soon as the defibrillator is available—this is the only intervention proven to increase survival to hospital discharge. 1, 2
- Biphasic defibrillators: Use manufacturer recommendation (typically 120-200 joules initially); if unknown, use maximum available
- Monophasic defibrillators: 360 joules
- Subsequent shocks should be equivalent or higher energy
Resume CPR immediately after shock delivery (starting with compressions, without pulse or rhythm check) for exactly 2 minutes before reassessing rhythm 1, 2
Administer epinephrine 1 mg IV/IO every 3-5 minutes throughout the resuscitation 2, 3
For refractory VF/pVT (persisting after 2-3 shocks): Administer antiarrhythmic medication—either amiodarone or lidocaine 2, 3
For Asystole or Pulseless Electrical Activity (PEA):
Begin CPR immediately and administer epinephrine 1 mg IV/IO every 3-5 minutes 2, 3
Aggressively search for and treat reversible causes (H's and T's): 1
- Hypovolemia, Hypoxia, Hydrogen ion (acidosis), Hypo/hyperkalemia, Hypothermia
- Tension pneumothorax, Tamponade (cardiac), Toxins, Thrombosis (pulmonary), Thrombosis (coronary)
Advanced Airway Management
Place an endotracheal tube or supraglottic airway device without interrupting chest compressions. 2, 3 The timing of airway placement should not delay CPR or defibrillation. 1
Immediately confirm tube placement with waveform capnography—this is mandatory, not optional. 1, 2, 3
After advanced airway placement: 1, 2, 3
- Deliver 1 breath every 6 seconds (10 breaths per minute)
- Continue chest compressions continuously without pauses for ventilation
- No longer use 30:2 compression-ventilation cycles
Critical pitfall: Avoid excessive ventilation, which decreases venous return and cardiac output. 1
Monitoring Resuscitation Quality
Use quantitative waveform capnography throughout resuscitation: 1, 2
- Target PETCO₂ >10 mmHg during CPR
- If PETCO₂ <10 mmHg, immediately improve CPR quality (deeper compressions, faster rate, minimize interruptions)
- An abrupt sustained increase in PETCO₂ (typically ≥40 mmHg) indicates return of spontaneous circulation (ROSC) 1
If intra-arterial pressure monitoring is available: Target relaxation phase (diastolic) pressure >20 mmHg 1
Important caveat: Do not use ETCO₂ alone to predict mortality or terminate resuscitation efforts. 2
Medication Administration
Establish IV or intraosseous (IO) access early for medication delivery 3
Epinephrine 1 mg IV/IO every 3-5 minutes improves survival, particularly in nonshockable rhythms 1, 2, 3
For refractory VF/pVT, administer antiarrhythmics: 2
- Amiodarone (preferred) or
- Lidocaine (alternative)
Recognition of ROSC
Signs of ROSC include: 1
- Palpable pulse and measurable blood pressure
- Abrupt sustained increase in PETCO₂ (typically ≥40 mmHg)
- Spontaneous arterial pressure waves on intra-arterial monitoring
Post-Resuscitation Care
Immediately after achieving ROSC: 3
Maintain oxygenation: Target oxygen saturation 92-98%—avoid both hypoxia and hyperoxia 2, 3
Maintain hemodynamic stability: Target mean arterial pressure ≥65 mmHg 3
Initiate targeted temperature management immediately for all patients who do not follow commands after ROSC to optimize neurological outcomes 1
Consider emergent coronary angiography for patients with ST-segment elevation on ECG or signs of ongoing myocardial ischemia 2
Special Populations
Pregnant patients: Perform manual lateral uterine displacement to relieve aortocaval compression during CPR 2
Hypothermic patients: Continue resuscitation efforts until the patient is rewarmed—standard ACLS medications and defibrillation should be attempted 1, 2
Opioid overdose with respiratory arrest: Focus on airway management and ventilation first; naloxone administration should not delay CPR if cardiac arrest occurs 1
Traumatic cardiac arrest: Despite historically poor outcomes, initiate ACLS regardless of initial rhythm, with emphasis on rapid transport and addressing reversible causes (tension pneumothorax, hemorrhage, tamponade) 4
System Considerations
Consider extracorporeal CPR (ECPR) for select patients when conventional CPR is failing, particularly in witnessed arrests with shockable rhythms 2
The survival equation: Without treatment, survival declines approximately 5.5% per minute; early CPR (within 4-6 minutes) and defibrillation (within 10-12 minutes) are essential for meaningful survival 5