Physio-Control LIFEPAK CR Plus - Manual (Page 59)

LIFEPAK CR Plus and LIFEPAK EXPRESS Defibrillator Operating Instructions A-7
©2009-2010 Physio-Control, Inc.
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Specifications
CLINICAL SUMMARY: 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 is 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.
Ventricular Tachycardia
Seventy-two episodes of ventricular tachycardia (VT), induced in 62 patients, were treated with
randomized shocks. High rates of conversion were observed with biphasic and monophasic shocks.
Sample sizes were too small to statistically determine the relationship between success rates of the
waveforms tested.
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
1
st Shock Success
Exact 95% Confidence Interval
200 J MDS 61/68 (90%) 80 to 96%
200 J BTE 39/39 (100%) 91 to 100%
130 J BTE 39/47 (83%) 69 to 92%