Shock early, resume CPR immediately for 2 min, give adrenaline after initial shocks fail and amiodarone (or lidocaine) for persisting VF, and treat the cause.
At the bedside
Timed steps- 1
Shock immediately
0 minBiphasic at the manufacturer's recommended energy (commonly 150-200 J; if unknown use maximum). Resume CPR immediately without pulse check.
- 2
Rhythm check → 2nd shock
2 minStill VF/pVT: shock (same or higher energy), resume CPR. Get IV access (IO if IV fails).
- 3
3rd shock, then drugs
4 minAfter the 3rd shock: adrenaline 1 mg IV and amiodarone 300 mg IV (ERC timing). AHA: adrenaline after initial defibrillation attempts fail; amiodarone or lidocaine for shock-refractory VF.
- 4
Repeat adrenaline
Every 3-5 min1 mg every alternate 2-min cycle.
- 5
Second antiarrhythmic dose
After 5th shockAmiodarone 150 mg (or lidocaine 0.5-0.75 mg/kg).
- 6
Optimise and think
Persisting VFCheck pad contact and position, consider antero-posterior pads (vector change); check K+, Mg2+, ischaemia; consider early PCI or ECPR where available. VC and double sequential defibrillation are not established (AHA 2025).
- 7
Up to 3 stacked shocks
Monitored, witnessed VF in ICU or cath labIf pads are already on, give up to three quick successive shocks before starting compressions (ERC).
Vasopressor in arrest
Adrenaline (epinephrine)
- Dose
- 1 mg every 3-5 min, starting after the 3rd shock (ERC)
- Preparation
- 1 mL of 1 mg/mL ampoule, or 10 mL of 100 mcg/mL
Antiarrhythmic for shock-refractory VF/pVT
Amiodarone
- Dose
- 300 mg after 3rd shock; 150 mg after 5th shock
- Preparation
- 150 mg/3 mL ampoules: 300 mg = 6 mL; may dilute to 20 mL D5
Alternative antiarrhythmic
Lidocaine (lignocaine)
- Dose
- 1-1.5 mg/kg, then 0.5-0.75 mg/kg (max 3 mg/kg)
- Worked example
- 70 kg: 100 mg (5 mL of 2%), then 50 mg
References
- 1
- 2
- 3
- 4
- 5
Shockable rhythm loop
Step 1 of ~6
Shock (biphasic 150-200 J or maximum)
Based on Soar J, Böttiger BW, Carli P, et al; Part 9: Adult Advanced Life Support: 2025 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Educational use; follow local protocol.
Evidence
- AHA 2025: biphasic preferred; single shocks rather than stacked; manufacturer energy (maximum if unknown); higher energy for subsequent shocks may be considered. Adrenaline 1 mg every 3-5 min; in shockable rhythms after initial defibrillation attempts fail. Amiodarone or lidocaine may be considered for shock-refractory VF/pVT. Routine calcium, bicarbonate and magnesium are not recommended.
- ALPS (2016): amiodarone and lidocaine did not improve survival to discharge overall, but improved survival in bystander-witnessed arrests.
- PARAMEDIC2 (2018): adrenaline improved 30-day survival but not favourable neurological survival.
- DOSE-VF (2022): vector change and double sequential defibrillation improved survival in refractory VF by intention-to-treat; AHA 2025 judges usefulness "not established" given methodological concerns.
Controversies
- Adrenaline timing in VF differs slightly between AHA ("after initial shocks fail") and ERC ("after the 3rd shock").
- Double sequential defibrillation risks defibrillator damage and requires millisecond timing.
- ECPR for refractory VF needs a system (rapid transport, cannulation team) that very few Indian centres have.
🇮🇳 India notes
- Biphasic defibrillators are now standard in most Indian ICUs; older monophasic units (360 J) may still be found in smaller hospitals.
- Lidocaine for IV use must be the preservative-free plain 2% preparation; avoid adrenaline-containing local anaesthetic vials.
References
- 1
- 2
- 3
- 4
- 5
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