Quality assessment of defibrillation and advanced life support using data from the medical control module of the defibrillator

What actually occurred during the two last links in the 'chain of survival: defibrillation and advanced life support (ALS), was studied in 156 patient s with cardiac arrest of cardiac aetiology using the computer recording of the defibrillator and the Utstein-style data record. Ten patients (6%) surv ived. The ECG artefacts caused by chest compressions enabled a detailed ana lysis of compression rates (median 108 min(-1)) and duration of important c ompression free periods. The time from initiation of monitoring during asys tole until chest compressions were initiated was median 29 s, significantly shorter than during electromechanical dissociation (EMD, 109 s; P < 0.001) . These times were both significantly longer than the median time from init iation of monitoring until the first shock was given in cases with VF (19 s ; P < 0.001), A total of 883 shocks (median six shocks) were administered t o 110 patients with a significant difference in number of shocks between su rvivors and non-survivors, one versus seven, respectively. The success rate for the first shock and all shocks defined as non-VT/VF 5 s after the shoc k, was 75 and 63%, respectively. However, just 10% of all shocks resulted i n a rhythm with a pulse and only 4% resulted in sustained return of spontan eous circulation (ROSC). An isoelectric period followed 38% of the shocks, and in 27% this lasted more than 20 s, with five patients obtaining electri cal activity with a pulse after more than 30 s of isoelectric EGG. Thoracic impedance did not affect the shuck efficacy. The method of analysing resus citation we describe may be useful for quality improvement. (C) 1999 Elsevi er Science Ireland Ltd. All rights reserved.