A short delay from out of hospital cardiac arrest to call for ambulance increases survival.

AIM To describe the relative impact on survival of the delay from estimated time of collapse to call for an ambulance among patients who suffer from a bystander witnessed out of hospital cardiac arrest of a cardiac aetiology. METHODS A majority of all ambulance organizations in Sweden (covering 85% of Sweden inhabitants) participate in a National survey of out of hospital cardiac arrest. RESULTS In all there were 9340 patients with a bystander witnessed cardiac arrest of a cardiac aetiology in whom cardiopulmonary resuscitation (CPR) was attempted participating in this survey. Survival at one month among patients with a delay between estimated time of collapse and call for ambulance of < or =4 min (median) was 6.9% versus 2.8% among patients with a median of >4 min (P<0.0001). When adjusting for age, sex, initial rhythm, estimated interval between collapse and start of CPR, place of arrest and the interval between call for ambulance and arrival of the rescue team, the odds ratio for survival was 0.70 (0.95% CI. 0.58-0.84) per unit increase of the natural logarithm of delay in minutes between collapse and call. CONCLUSION Among patients with a bystander witnessed out of hospital cardiac arrest of a cardiac aetiology increased delay from estimated time of collapse to call for an ambulance decreased the chance of survival.