Influence on outcome after cardiac arrest of time elapsed between call for help and start of bystander basic CPR. The Belgian Cerebral Resuscitation Study Group.

The exact impact of the 'interval between cardiac arrest (CA) and the start of basic cardiopulmonary resuscitation (CPR) performed by bystanders' on outcome is not fully established. We retrospectively evaluated data with regard to response intervals of 1195 out-of-hospital CA interventions where bystander CPR was performed and continued by the eight mobile intensive care units (MICUs) participating in the Belgian Cerebral Resuscitation Registry between 1982 and 1990. Partial correlations between time elapsed from CALL to CPR by lay public and outcome were determined when the effect of response times of 1st and 2nd tier were removed. The following groups were studied: ventricular fibrillation (VF), asystole and electromechanical dissociation (EMD), non-witnessed and witnessed. Good outcome was represented by initial restoration of spontaneous circulation (ROSC successes) and by prolonged survival (CPR successes) being 22.7 and 9.7%, respectively. The mean time +/- S.E.M. between CALL and CPR initiated by lay people for the studied population (n = 1195) was 2.5 +/- 0.1 min. The partial correlation coefficient between prolonged survival and time passed between CALL and bystander CPR was negative for all types of CA, yet significance was reached only in the non-witnessed group. Using ROSC as the endpoint significance is achieved in all groups except the VF patients, where the intervention times were shorter. In our population, prolonged survival was independently and negatively influenced by a delay between CALL and any CPR in the non-witnessed CA group (n = 421).