Can a pulseless ventricular tachycardia be defibrillated with 120 J?

Yes, 120 Joules Can Successfully Defibrillate Pulseless VT

Yes, you can defibrillate pulseless ventricular tachycardia with 120 J using a biphasic defibrillator, as this energy level falls within the recommended range and has demonstrated high efficacy (85-98%) for terminating ventricular arrhythmias. 1

Key Management Principles

Pulseless VT is treated identically to ventricular fibrillation - this is a critical distinction from stable VT with a pulse. 2, 3 You must use unsynchronized high-energy shocks (defibrillation doses), not synchronized cardioversion. Attempting to synchronize on pulseless VT wastes precious time and may fail to deliver a shock at all. 3

Energy Dosing for Biphasic Defibrillators

First Shock

• Use the manufacturer's recommended dose (typically 120-200 J for biphasic devices) 2, 1
• If manufacturer settings are unknown, using maximal dose is reasonable 1
• For rectilinear biphasic (RLB) waveforms specifically, a selected dose of 120 J typically delivers nearly 150 J to most patients due to impedance-based adjustments 1

Evidence Supporting 120 J

The 2015 AHA Guidelines explicitly state that biphasic shocks using 200 J or less achieve first-shock termination rates consistently in the 85-98% range. 1 Observational data show that 120 J settings with RLB waveforms achieved 87.8% initial VF termination rates and 86.4% for persistent VF. 1

Subsequent Shocks if First Fails

If 120 J doesn't work:

• Second and subsequent shocks should be at least equivalent energy 2
• Higher energy doses may be considered (escalating to maximum device capability) 1
• Follow manufacturer's instructions for fixed versus escalating protocols 1
• Research shows conversion rates increase substantially at 360 J if lower energies fail 4

Critical Workflow Points

1. Minimize interruptions in CPR - charge the defibrillator while compressions continue 2
2. Single shock strategy - deliver ONE shock, then immediately resume CPR for 2 minutes before rhythm recheck 2, 5
3. No pulse checks immediately after shock - start compressions immediately 2
4. Biphasic waveforms are strongly preferred over monophasic (which require 360 J) 1, 5

Common Pitfalls to Avoid

• Don't attempt synchronized cardioversion on pulseless VT - this is for stable VT with pulses only (starting at 100 J synchronized) 3, 2, 3
• Don't delay for "optimal" energy selection - any appropriate biphasic energy (120-200 J) works well; speed matters more 2, 1
• Don't deliver stacked shocks without CPR - the single-shock-plus-immediate-CPR strategy improves survival compared to three stacked shocks 5
• Don't confuse polymorphic VT with monomorphic VT - polymorphic (irregular) VT cannot be synchronized and requires defibrillation doses like pulseless VT 3, 2, 3

The bottom line: 120 J biphasic defibrillation is appropriate, effective, and guideline-concordant for pulseless VT, with the understanding that you may need to escalate energy if the first shock fails.