Cardiac Arrest & Resuscitation (ACLS)
Comprehensive emergency resuscitation guide covering high-quality chest compressions, shockable vs non-shockable pathways, double sequential defibrillation, ECMO/E-CPR, and targeted temperature management.
Resuscitation Quick Ribbon (First 2 Minutes)
Bottom-Line Clinical Pearl
Survival in cardiac arrest hinges on immediate high-quality chest compressions (100–120/min, 5–6 cm depth, complete recoil, CCF > 80%) and rapid defibrillation. For refractory VF/pVT after >= 3 standard shocks, early vector change or Double Sequential External Defibrillation (DSED) significantly improves survival to discharge. In post-ROSC care, avoid hyperthermia (> 37.5°C), target MAP >= 65 mmHg, and obtain an immediate 12-lead ECG for emergent coronary catheterization.
1. Immediate Resuscitation & The First 5 Minutes
Upon identifying an unresponsive patient without a palpable carotid pulse (assessed in < 10 seconds), immediately activate the resuscitation team, call for a defibrillator, and initiate continuous chest compressions. Establish high-flow oxygenation via bag-valve-mask (BVM) with a 30:2 ratio or asynchronous 1 breath every 6 seconds (10 breaths/min) once an advanced airway is placed.
High-Performance CPR Metrics: Depth 5–6 cm (2–2.4 in), rate 100–120/min, 100% full recoil. Compress-chest-fraction (CCF) must exceed 80%. Hover hands over the chest while defibrillator charges; clear only for the 2-second rhythm check and shock delivery.
| Phase | Action | Target Metric | Drug / Electricity |
|---|---|---|---|
| 0–2 min | High-quality CPR + Pad Placement | CCF > 80% | Rhythm check at 2 min |
| Shockable (VF/pVT) | Immediate Defibrillation | Biphasic 200J | Resume CPR immediately without pulse check |
| Cycle 2 | Epinephrine + Vascular Access | IV/IO antecubital or proximal tibia | Epinephrine 1 mg IV/IO (1:10,000) |
| Cycle 3 (Persistent VF) | Antiarrhythmic Bolus | Assess refractory status | Amiodarone 300 mg IV/IO OR Lidocaine 1.5 mg/kg |
| Refractory VF (>= 3 shocks) | Dual Defibrillation / Vector Change | Anterior-Posterior Pad Setup | Double Sequential External Defibrillation (DSED) |
2. Shockable (VF/pVT) vs. Non-Shockable (PEA/Asystole) Algorithms
Ventricular Fibrillation (VF) and Pulseless Ventricular Tachycardia (pVT) are primary electrical arrests. Survival depends directly on time to first shock. For non-shockable rhythms (PEA/Asystole), the arrest is metabolic or mechanical; immediate epinephrine (1 mg) and rapid identification of the reversible H's and T's dictate outcomes.
| Reversible Cause (H's & T's) | Bedside Clues & Diagnostic Triggers | Immediate ED Intervention |
|---|---|---|
| Hypovolemia | Trauma, GI bleed, flat IVC on POCUS | Rapid crystalloid bolus, Massive Transfusion Protocol (1:1:1) |
| Hypoxia | Airway obstruction, acute cyanosis, tension pneumo | Immediate endotracheal intubation, suction, 100% FiO2 |
| Hydrogen ion (Acidosis) | DKA, profound lactic acidosis, renal failure | Hyperventilation, Sodium bicarbonate 1–2 mEq/kg IV push |
| Hyperkalemia | Peaked T waves on baseline ECG, missed dialysis | Calcium gluconate 3g (or CaCl 1g), insulin + D50W, bicarb, albuterol |
| Hypothermia | Core temp < 30°C, outdoor exposure | Active internal rewarming, warm IV fluids, ECMO/CPB |
| Tension Pneumothorax | Absent breath sounds, tracheal shift, subcutaneous air | Immediate needle thoracostomy (5th ICS anterior axillary line) |
| Cardiac Tamponade | Pericardial effusion + RV collapse on subxiphoid POCUS | Immediate bedside ultrasound-guided pericardiocentesis |
| Toxins (OD) | TCA, beta-blocker, calcium channel blocker, opioids | Naloxone, high-dose insulin euglycemia (HIET), intralipid, sodium bicarb |
| Thrombosis (Pulmonary - PE) | Massive RV dilation / McConnell sign on POCUS | Systemic Alteplase (tPA) 50 mg IV bolus during arrest |
| Thrombosis (Coronary - STEMI) | Known CAD, sudden collapse with chest pain | Mechanical CPR + emergent cath lab transport (E-CPR / ECMO) |
3. Refractory VF Strategies: Vector Change & DSED
Refractory VF is defined as persistent VF or pVT despite >= 3 standard anterolateral shocks, epinephrine, and antiarrhythmic therapy. The DOSE VF randomized clinical trial demonstrated that both Vector Change (VC) and Double Sequential External Defibrillation (DSED) significantly increase survival to hospital discharge compared to continued standard shocks.
- Vector Change (VC): Switch pads from anterolateral (sternum/apex) to anteroposterior (left precordium and left infrascapular back). Changes the electrical vector across the left ventricle.
- Double Sequential External Defibrillation (DSED): Apply two sets of defibrillator pads (set 1 anterolateral, set 2 anteroposterior). Connect both to separate defibrillators. Fire defibrillator 1 followed immediately (< 1 second) by defibrillator 2.
- Esmolol Protocol in Refractory VF: In sympathetic storm refractory VF, esmolol 500 mcg/kg IV bolus followed by 50–100 mcg/kg/min infusion reduces myocardial oxygen demand and blunts toxic catecholamines.
4. Post-Resuscitation Care & ROSC Optimization
Return of Spontaneous Circulation (ROSC) is the beginning of the resuscitation, not the end. The postcardiac arrest syndrome is characterized by brain injury, myocardial dysfunction, systemic ischemia/reperfusion response, and persistent precipitating pathology.
| System | Post-ROSC Target | Intervention / Management |
|---|---|---|
| Hemodynamics | MAP 65–85 mmHg, SBP >= 90 | Norepinephrine 0.05–0.5 mcg/kg/min; add Epinephrine or Dobutamine for cardiogenic shock |
| Oxygenation | SpO2 92–98%, PaO2 100–150 mmHg | Wean FiO2 immediately to avoid hyperoxic cerebral free-radical damage |
| Ventilation | PaCO2 35–45 mmHg (Normocapnia) | Avoid hyperventilation (causes cerebral vasoconstriction and ischemia) |
| Coronary Reperfusion | Immediate 12-lead ECG | If STEMI or high suspicion of acute coronary occlusion: emergent cardiac catheterization |
| Targeted Temp (TTM) | Strictly avoid hyperthermia (> 37.5°C) | Cooling catheter or surface cooling pads; target 32–36°C for 24 hours in comatose patients |
5. Medicolegal Pearls, Pitfalls & Board Traps
The Routine Bicarb/Calcium Trap: Routine administration of sodium bicarbonate or calcium chloride in undifferentiated cardiac arrest does NOT improve survival and produces hyperosmolarity, intracellular acidosis (via paradoxical CO2 shift), and hypocalcemia. Restrict to documented hyperkalemia, renal failure, or TCA toxicity.
- Pulse Check Illusion: Never check a pulse during active CPR. Pulse checks must occur only at the 2-minute interval and must never take longer than 10 seconds. If uncertain, assume pulseless and resume compressions.
- ETCO2 Prognostication: An end-tidal CO2 (ETCO2) < 10 mmHg after 20 minutes of high-quality CPR correlates with near 0% survival. A sudden jump in ETCO2 (e.g. from 15 to 40+ mmHg) is the most reliable early indicator of ROSC.
- Airway Prioritization Trap: Do NOT halt chest compressions to attempt endotracheal intubation. Supraglottic airways (i-gel / King LT) or BVM with a tight two-hand seal are equivalent or superior to intubation during early resuscitation.
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