Defibrillation for adult ventricular fibrillation

Ventricular Fibrillation. [Source]

Three-quarters of arrests are due to ventricular fibrillation. Only a small proportion is due to electromechanical dissociation (EMD), the rest being due to asystole.

EMD usually has a potentially reversible cause:

• hypovolaemia
• hypoxia
• hyperkalaemia
• hypokalaemia
• hypothermia
• tension pneumothorax
• tamponade
• toxicity due to drugs
• thromboembolism

Defibrillation is used to convert VF to sinus rhythm. Previously the recommendation was Initially a monophasic 200-joule shock, followed by 200-J and then 360-J shocks. New resusciation guidelines now recommend shocking at 360-J. Biphasic defibrillation is currently the best treatment for adult VF and should be used when available.

2010 AHA ACLS algorithm

Further reading:

1. Biphasic or monophasic defibrillation for adult ventricular fibrillation. [BestBets]