Relationship of Humidity and Atmospheric Pressure With the Risk of Out-of-hospital Cardiac Arrest

Introduction: Climate change, which affects human health, is one of the most important public health concerns. Few studies have examined the effects of humidity and atmospheric pressure as risk factors on the cardiac system and Out-of-hospital Cardiac Arrest. Objective: This study aimed to determine the relationship between climatic variables (humidity and atmospheric pressure) with Out-of-hospital Cardiac Arrest , and its outcome over 3 years (2016-2018). Materials and Methods: This is an ecological time-series study. Participants were 392 patients with Out-of-hospital Cardiac Arrest referred to a governmental Hospital in Rasht City, Iran from 2016 to 2018. Meteorological data and information related to Out-ofhospital Cardiac Arrest and its consequences were collected from reliable resources and were analyzed in R software. Results: Low humidity increased the relative risk of Out-of-hospital Cardiac Arrest (OR=1.54, 95%CI: 1.001-2.69, P=0.001) and failed cardiopulmonary resuscitation (OR=1.76, 95% CI; 1.006-3.79, P=0.001). Higher atmospheric pressure was associated with increased risk of Out-of-hospital Cardiac Arrest (OR=1.16, 95%CI; 1.001-1.78, P=0.001) and unsuccessful cardiopulmonary resuscitation (OR=1.039, 95% CI; 1.005-1.91, P=0.001). Conclusion: Decreased humidity and increased atmospheric pressure are associated with an increased number of Out-of-hospital Cardiac Arrest cases and failure of cardiopulmonary resuscitation. Informing people with cardiovascular disease to avoid such weather conditions, as well as preparing the medical care team and designing early warning systems, can reduce the adverse effects of climate change on the heart.