Difference in survival after out-of-hospital cardiac arrest between the two largest cities in Sweden: a matter of time?

BACKGROUND: Dramatic differences in survival after out-of-hospital cardiac arrests (OHCA) reported from different geographical locations require analysis. We therefore compared patients with OHCA in the two largest cities in Sweden with regard to various factors at resuscitation and outcome.

SETTING: All patients suffering an OHCA in Stockholm and Goteborg between 1 January 2000 and 30 June 2001, in whom cardiopulmonary resuscitation (CPR) was attempted were included in this retrospective analysis.

RESULTS: All together, 969 OHCA in Stockholm and 398 in Goteborg were registered during the 18-month study period. There were no differences in terms of age, gender, and percentage of witnessed cases or percentage of patients who had received bystander CPR. However, the percentage of patients with ventricular fibrillation (VF) at arrival of the ambulance crew was 18% in Stockholm versus 31% in Goteborg (P <0.0001). The percentage of patients who were alive 1 month after cardiac arrest was 2.5% in Stockholm versus 6.8% in Goteborg (P=0.0008). Various time intervals such as cardiac arrest to calling for an ambulance, cardiac arrest to the start of CPR and calling for an ambulance to its arrival were all significantly longer in Stockholm than in Goteborg.

CONCLUSION: Survival was almost three times higher in Goteborg than in Stockholm amongst patients suffering an OHCA. This is primarily explained by a higher occurrence of VF at the time of arrival of the ambulance crew, which in turn probably is explained by shorter delays in Goteborg. The reason for the difference in time intervals is most likely multifactorial, with a significantly higher ambulance density in Goteborg as one possible explanation.