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Appendix B
Clinical Summaries
LIFEPAK 20e Defibrillator/Monitor Operating Instructions B-1
©2006-2013 Physio-Control, Inc.
DEFIBRILLATION OF VENTRICULAR FIBRILLATION AND VENTRICULAR
TACHYCARDIA
Background
Physio-Control conducted a multi-centered, prospective, randomized and blinded clinical trial of
biphasic truncated exponential (BTE) shocks and conventional monophasic damped sine wave
(MDS) shocks. Specifically, the equivalence of 200 J and 130 J BTE shocks to 200 J MDS
shocks
1
was tested.
Methods
Ventricular fibrillation (VF) was induced in 115 patients during evaluation of implantable
cardioverter defibrillator function and 39 patients during electrophysiologic evaluation of
ventricular arrhythmias. After 19±10 seconds of VF, a customized defibrillator delivered an
automatically randomized shock. Efficacy was based on success of this shock. To demonstrate
equivalence of test shocks to control shocks, the 95% upper confidence limit of the difference in
efficacy (95UCLD), control minus test, was required to be less than 10%.
Results
Ventricular Fibrillation
The efficacy of the 200 J BTE shocks was demonstrated to be at least equivalent to the efficacy
of 200 J MDS shocks (95UCLD=2%). The difference in success rates of 200 J MDS minus 200 J
BTE shocks was -10% (exact 95% confidence interval from -27% to 4%). The 130 J BTE shocks
were not demonstrated equivalent to 200 J MDS shocks (95UCLD=22%). However, neither was
their efficacy significantly lower than that of the 200 J MDS shocks (statistical power limited by
small sample sizes). For all shock types, hemodynamic parameters (oxygen saturation and
systolic and diastolic blood pressure) were at or near their pre-induction levels by 30 seconds
after successful shocks.
1
S.L. Higgins et al., “A comparison of biphasic and monophasic shocks for external defibrillation,” Prehospital
Emergency Care, 2000, 4(4):305-13.
Shock
Ventricular Fibrillation
1st Shock Success
Exact 95% Confidence Interval
200 J MDS 61/68 (90%) 80-96%
200 J BTE 39/39 (100%) 91-100%
130 J BTE 39/47 (83%) 69-92%