Low Incidence of Death and Renal Failure in United States Military Service Members Hospitalized with Exertional Heat Stroke: A Retrospective Cohort Study

Abstract

Introduction: The goal of the current study was to characterize the rate and estimate associated mortality and morbidity of exertional heat stroke (EHS) in U.S. military service members. Materials and Methods: The current study was a retrospective cohort medical chart review study of all active-duty U.S. military service members, hospitalized with EHS at any MTF in the world between January1, 2007 and July 1, 2014. Enrolled patients were identified by altered mental status and elevated temperatures associated with physical exercise. Results: Out of 607 service members with an International Classification of Disease code indicating any type of heat injury, 48 service members met inclusion criteria for EHS. Core temperature was M = 105.8°F (41°C), standard deviation = 1.43, 90% were diagnosed with EHS prior to hospitalization, and 71% received prehospital cooling. Meantime to normothermia post-hospitalization was 56 minutes (standard deviation = 79.28). Acute kidney injury was diagnosed in 40% of patients although none developed hyperkalemia or required dialysis. Disseminated intravascular coagulation was rare (4%, n = 2) and overall observed mortality was very low (2%, n = 1). Conclusion: EHS is aggressively identified and treated in U.S. Military Treatment Facilities. Mortality and morbidity were strikingly low.