Analysing ventricular fibrillation ECG-signals and predicting defibrillation success during cardiopulmonary resuscitation employing N(alpha)-histograms

Mean fibrillation frequency may predict defibrillation success during cardi opulmonary resuscitation (CPR). N(alpha)-histogram analysis should be inves tigated as an alternative. After 4 min of cardiac arrest, and 3 versus 8 mi n of CPR, 25 pigs received either vasopressin or epinephrine (0.4, 0.4, and 0.8 U/kg vasopressin versus 45, 45, and 200 mug/kg epinephrine) every 5 mi n with defibrillation at 22 min. Before defibrillation, the N(alpha)-parame ter histogramstart/histogramwidth and the mean fibrillation frequency in re suscitated versus non-resuscitated pigs were 2.9 +/- 0.4 versus 1.7 +/- 0.5 (P = 0.0000005); and 9.5 +/- 1.7 versus 6.9 +/- 0.7 (P = 0.0003). During t he last minute prior to defibrillation, histogramstart/histogramwidth of gr eater than or equal to 2.3 versus mean fibrillation frequency ! 8 Hz predic ted successful defibrillation with subsequent return of a spontaneous circu lation for more than 60 min with sensitivity, specificity, positive predict ive value and negative predictive value of 94 versus 82%, 96 versus 89%, 98 versus 93% and 90 versus 74%, respectively. We conclude, that N(alpha)-ana lysis was superior to mean fibrillation frequency analysis during CPR in pr edicting defibrillation success, and distinction between vasopressin versus epinephrine effects. (C) 2001 Elsevier Science Ireland Ltd. All rights res erved.