From the Guidelines
Defibrillation at 200 joules is typically initiated for ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT) as the initial energy setting when using a biphasic defibrillator. This recommendation is based on the most recent and highest quality study, which suggests that a 200J initial shock is effective in terminating VF and minimizing myocardial damage 1. After identifying cardiac arrest and confirming a shockable rhythm through rhythm assessment, immediately deliver the shock at 200J, followed by immediate resumption of CPR.
Key Considerations
- For subsequent shocks, maintain or increase the energy level according to manufacturer recommendations, usually between 200-360J.
- If using an older monophasic defibrillator, a higher initial energy of 360J is recommended instead.
- Early defibrillation significantly improves survival rates, with a 10% decrease in survival for each minute defibrillation is delayed.
- Always ensure safety by clearly announcing "clear" and visually confirming no one is touching the patient before delivering the shock.
Evidence Summary
The 2015 American Heart Association guidelines update for cardiopulmonary resuscitation and emergency cardiovascular care supports the use of 200J as the initial energy setting for biphasic defibrillators 1, 2. The evidence suggests that this energy level is effective in terminating VF and minimizing myocardial damage, while also improving survival rates.
Clinical Implications
In clinical practice, it is essential to prioritize early defibrillation and follow the recommended energy settings to maximize the chances of successful resuscitation. By following these guidelines, healthcare providers can improve patient outcomes and reduce morbidity and mortality associated with cardiac arrest.
From the Research
Defibrillation Energy Levels
- The recommended initial energy for biphasic defibrillators is 150-200 J, as stated in the European Resuscitation Council guidelines for cardiopulmonary resuscitation in 2005 3.
- For second and subsequent shocks, the recommended energy is 150-360 J for biphasic defibrillators 3.
- In the case of refractory ventricular fibrillation, double sequential external defibrillation has been used with energy levels of 200 J and 400 J 4.
- A study comparing monophasic and biphasic defibrillation waveforms found that shock success within the first three ascending energy shocks for biphasic waveforms (120, 150, 200J) was superior to monophasic waveforms (200, 300, 360J) for patients initially presenting in a shockable rhythm 5.
Specific Energy Level of 200 J
- The energy level of 200 J is mentioned as part of the recommended initial energy range for biphasic defibrillators 3.
- In a case report, a patient received six biphasic defibrillations using standard energy levels, which may have included 200 J, before double sequential external defibrillation was applied 6.
- A study used an energy level of 200 J for defibrillation in patients with out-of-hospital cardiac arrest, with a step-up protocol to 300 J and 360 J for subsequent shocks 5.
- Another study used an energy level of 200 J for the first defibrillation, followed by 400 J using two biphasic defibrillators in a case of refractory ventricular fibrillation 4.