Surviving out of hospital cardiac arrest at home: a postcode lottery?

OBJECTIVE: To find out if the response time, distance travelled to scene, and geographical location affect survival from out of hospital cardiac arrest (OHCA).
METHODS: Retrospective cohort study over 10 years, 1 December 1991 to 1 August 2001. Outcome and demographic data were obtained for 1956 OHCAs occurring at home, in the Lothians region, from the Heartstart Scotland database. Survival rates to hospital admission and discharge were examined by postcode district.
RESULTS: Certain postcode areas were served by quicker response times and shorter journeys. The survival to admission rate was greater in those areas where the median response time was <10 minutes (13.5% versus 8.1%, p<0.05). There was greater survival to discharge in these areas but not significantly so (4.1% versus 3.2%, p = 0.42). Survival to admission was more likely in areas where the median distance travelled was <four miles (13.3% versus 9.7%, p<0.05) but not survival to discharge (4.0% versus 3.7%, p = 0.72). A close correlation between distance travelled and response time was shown (Pearson = 0.93, p<0.01), likewise between distance travelled and survival to admission (Spearman = -0.87, p<0.01). Certain areas, particularly those at greater geographical distance from ambulance dispatch points, were found to be associated with significantly lower survival to admission rates.
CONCLUSIONS: Survival to admission from OHCA is strongly influenced by response time and distance travelled to the scene. The geographical location of an arrest can potentially influence survival to admission. Measures should be taken to strategically position ambulance dispatch points and to task the nearest geographically available vehicle to attend an OHCA.