Out-of-hospital cardiac arrest in Victoria: rural and urban outcomes

Objective: To compare the survival rate from out-of-hospital cardiac arrest in rural and urban areas of Victoria, and to investigate the factors associated with these differences. Design: Retrospective case series using data from the Victorian Ambulance Cardiac Arrest Registry. Setting: All out-of-hospital cardiac arrests occurring in Victoria that were attended by Rural Ambulance Victoria or the Metropolitan Ambulance Service. Participants: 1790 people who suffered a bystander-witnessed cardiac arrest between January 2002 and December 2003. Results: Bystander cardiopulmonary resuscitation was more likely in rural (65.7%) than urban areas (48.4%) (P = 0.001). Urban patients with bystander-witnessed cardiac arrest were more likely to arrive at an emergency department with a cardiac output (odds ratio [OR], 2.92; 95% Cl, 1.65-5.17; P < 0.001), and to be discharged from hospital alive than rural patients (urban, 125/1685 [7.4%]; rural, 2/105 [1.9%]; OR, 4.13; 95% Cl, 1.09-34.91). Major factors associated with survival to hospital admission were distance of cardiac arrest from the closest ambulance branch (OR, 0.87; 95% Cl, 0.82-0.92), endotracheal intubation (OR, 3.46; 95% Cl, 2.49-4.80), and the presence of asystole (OR, 0.50; 95% CI, 0.38-0.67) or pulseless electrical activity (OR, 0.73; 95% Cl, 0.56-0.95) on arrival of the first ambulance crew. Conclusions: Survival rates differ between urban and rural cardiac arrest patients. This is largely due to a difference in ambulance response time. As it is impractical to substantially decrease response times in rural areas, other strategies that may improve outcome after cardiac arrest require investigation.