Effect of location of out-of-hospital cardiac arrest on survival outcomes

This study aims to study how the effect of the location of patient collapses from cardiac arrest, in the residential and non-residential areas within Singapore, relates to certain survival outcomes. A retrospective cohort study of data were done from the Cardiac Arrest and Resuscitation Epidemiology (CARE) project. Out-of- hospital cardiac arrest (OHCA) data from October 2001 to October 2004 (CARE) were used. All patients with OHCA as confirmed by the absence of a pulse, unresponsiveness and apnoea were included. All events had occurred in Singapore. Analysis was performed and expressed in terms of the odds ratio (OR) and the corresponding 95% confidence interval (CI). A total of 2375 cases were used for this analysis. Outcomes for OHCA in residential areas were poorer than in non-residential areas-1638 (68.9%) patients collapsed in residential areas, and 14 (0.9%) survived to discharge. This was significantly less than the 2.7% of patients who survived after collapsing in a non-residential area (OR 0.31 [0.16 - 0.62]). Multivariate logistic regression analysis showed that location alone had no independent effect on survival (adjusted OR 1.13 [0.32 - 4.05]); instead, underlying factors such as bystander CPR (OR 3.67 [1.13 - 11.97]) and initial shockable rhythms (OR 6.78 [1.95 - 23.53]) gave rise to better outcomes. Efforts to improve survival from OHCA in residential areas should include increasing CPR by family members, and reducing ambulance response times.