Do neighbourhoods in Vancouver and surrounding areas demonstrate different rates of bystander CPR and survival for out-of-hospital cardiac arrest?

Objective: No prior work exists examining the relation between the geographic distribution of out-of-hospital cardiac arrest (OHCA) in the city of Vancouver and surrounding areas that may exhibit a clustering of cases. The primary objective of this study was to describe the distribution of OHCA within the Vancouver Coastal Health region using a geographic information system (GIS) analysis and appropriate statistical analyses.

Methods: This study was a post-hoc GIS-based analysis of OHCA patients in the city of Vancouver and surrounding areas, using data collected by the Resuscitation Outcomes Consortium between September 2007 and December 2011. The kernel density techniques and regression tree analysis using binary recursive partitioning were used.

Results: We examined 1617 cases of OHCA with a mortality rate of 86.5% (95% CI 84.8-88.2). The mean age of OHCA cases was 66.6 years (95% CI 65.7-67.5), and 33.6% (95% CI 31.3-35.9) were female. The proportion with an initial shockable rhythm (VF or pulseless VT) was 22.2% (95% CI 20.2-24.2); 42.3% (95% CI 39.9-44.7) of all cases received bystander CPR, and 49.7% (95% CI 47.3-52.1) were transported to the hospital by paramedics. The rate of survival to hospital discharge with favourable neurological status (FNS) Cerebral Performance Category (CPC) 1 or 2 was 10.4% (8.9-11.9). Distance of transport to the hospital (less than 2.7 km) was a significant predictor of survival with FNS, but income did not predict survival with FNS. Areas with higher proportions of commuters by car demonstrated lower rates of survival with FNS.

Conclusion: This is the first GIS-based study to examine OHCA in a single large Canadian centre. Clustering of OHCA consistent with areas of high population density was observed. Distance of transport was a significant predictor of survival with FNS for patients with OHCA. This may have important implications for future emergency medical services deployment and dispatch decision-making, and public policy initiatives.