• Roger D White, Thomas H Blackwell, James K Russell, David E Snyder, and Dawn B Jorgenson.
• Department of Anesthesiology, The Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA. white.roger@mayo.edu
• Resuscitation. 2005 Jan 1;64(1):63-9.

ObjectiveThis is a study of the influence of transthoracic impedance (TTI) on defibrillation, resuscitation and survival in patients with out-of-hospital cardiac arrest (OHCA), treated with a non-escalating impedance-compensating 150 J biphasic waveform defibrillator.MethodsCardiac arrest data from two EMS systems were analyzed retrospectively. All witnessed arrests from patients who presented with a shockable rhythm and were treated initially by BLS personnel were included (n = 102). For each defibrillation and resuscitation outcome variable, we tested differences in mean TTI for successful versus unsuccessful outcome. The effect of call-to-shock time on overall outcome was also examined.ResultsInitial shocks defibrillated 90% [83-95%] (95% confidence interval) of patients. Cumulative success with two shocks was 98% [93-100%] and with three shocks was 99% [95-100%]. TTI averaged 90 +/- 23 Omega. First-shock success, cumulative success through two shocks and cumulative success through the first-shock series were unrelated to TTI, as were BLS ROSC, pre-hospital ROSC, hospital admission and discharge. In contrast and consistent with previous findings, call-to-shock time was highly predictive of survival.ConclusionsHigh impedance patients were defibrillated by the biphasic waveform used in this study at high rates with a fixed energy of 150 J and without energy escalation. Rapid defibrillation rather than differences in patient impedance accounts for resuscitation success.

24 keywords...

hide…