Air Pollution and Activation of Mobile Medical Team for Out-of-hospital Cardiac Arrest

BACKGROUND:The association between air pollution exposure and cardiovascular events is well established, and the effect of short-term exposure on out-of-hospital cardiac arrest (OHCA) has received some attention. The effect of air pollution exposure and the activation of mobile intensive care units (MICUs) for cardiac arrest have never been studied.OBJECTIVE:We analyzed associations between air pollutants and MICU activation for OHCA.METHOD:This is a retrospective study including 4558 patients with OHCA and MICU activation from 2007 to 2012. A time-stratified case crossover design was used. Particulate matter (PM) of median aerodynamic diameter less than 2.5 μm (PM2.5), less than 10 μm, and ozone were the 3 main pollutants used to determine the effects of pollution exposure on the event.RESULTS:A daily average increase of 27.6 μg/m(3) in ozone was associated with an increase of MICU activation for OHCA the following day (odds ratio [OR], 1.13; 95% confidence interval [CI], 1.03-1.22). For women, a daily average increase of 27.6 μg/m(3) in ozone was associated with an increase of MICU activation for OHCA the following day (OR, 1.19; 95% CI, 1.01-1.37). An hourly average increase of 10.5 μg/m(3) in PM2.5 was associated with an increase of MICU activation for OHCA in the current hour (OR, 1.11; 95% CI, 1.02-1.19). For men, an increase in PM2.5 was associated with an increase in MICU activation for OHCA the current hour (OR, 1.10; 95% CI, 1.01-1.20). No association was found with PM of median aerodynamic diameter less than 10 μm.CONCLUSION:An association was found between air pollution and MICU activation for OHCA (ozone and PM2.5).