Physio-Control LIFEPAK 20e - Manual (Page 168)

Clinical Summaries
B-2 LIFEPAK 20e Defibrillator/Monitor Operating Instructions
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.
Conclusions
In this double-blinded study, the efficacy of the 200 J BTE shocks was demonstrated to be at
least equivalent to the efficacy of 200 J MDS shocks for defibrillation of short duration,
electrically-induced VF. However, the comparison of efficacy of 130 J biphasic and 200 J
monophasic shocks for VF was inconclusive. All waveforms tested provided a high rate of
termination of VT. The VT sample sizes were too small to statistically determine the relationship
between VT success rates of the waveforms tested.
Compared to conventional shocks for VF, we found no positive or negative effect of biphasic
shocks for VF on hemodynamic parameters following the defibrillating shock. It is possible that,
compared to 200 J monophasic shocks, 200 J biphasic shocks will in some cases enable earlier
termination of VF. Therefore, we conclude that biphasic shocks for VF delivered at conventional
energy levels have the potential to improve outcome in resuscitation of patients with cardiac
arrest.
Shock
Ventricular Tachycardia
1st Shock Success
Exact 95% Confidence Interval
200 J MDS 26/28 (93%) 77-99%
200 J BTE 22/23 (96%) 78-100%
130 J BTE 20/21 (95%) 76-100%