The influence of air pollution by PM2.5, PM10 and associated heavy metals on the parameters of out-of-hospital cardiac arrest.

Out-of-hospital cardiac arrest (OHCA), defined as abrupt cessation of mechanical activity of the heart, is one of the most common causes of death in high-income countries. Cardiac arrest is most often a result of severe cardiovascular disease. New evidence shows that air pollutants such as heavy metals and atmospheric particulate matter have an impact on the pathophysiology of many cardiovascular diseases as well on incidences of OHCA. This retrospective analysis includes all OHCA cases that occurred in central Poland covering the area of 11.711 km2 with the population density of 108 people per square kilometer. Among 2878 EMS-treated OHCA cases between 2013 and 2016, cardiopulmonary resuscitation (CPR) was attempted in 2076 (72%) patients. Concentrations of air pollutants were compared with temperature, humidity and clinical factors affecting the CPR. The study shows seasonal variation of PM 2.5 (p < 0.001), PM 10 (p < 0.001), As (p < 0.001) and Cd (p < 0.001) over the years. Air pollution has a significant effect on the parameters of pre-hospital evaluation in OHCA patients, especially with respect to the content of PM2.5/PM10 and heavy metals. Nickel exposure affects the incidence of initial shockable rhythm (IRR 0.92; p = 0.01) and effectiveness of CPR (IRR 0.94; p = 0.003). Arsenic has an impact on overall mortality (IRR 1.07; p = 0.01) and death upon the arrival of EMS team (IRR 1.15; p < 0.001). Overall mortality was also related to ambient levels of PM10 (IRR 1.004; p < 0.047).