Air pollution and activation of mobile medical team for out-of-hospital cardiac arrest

Abstract

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).