Cooling Modality Effectiveness and Mortality Associate With Prehospital Care of Exertional Heat Stroke Casualities.

BACKGROUND: Cold-water immersion is the gold standard for field treatment of an exertional heat stroke (EHS) casualty. Practical limitations may preclude this method and ice sheets (bed linens soaked in ice water) have emerged as a viable alternative. Laboratory studies suggest that this is an inferior method; however, the magnitude of hyperthermia is limited and may underestimate the cooling rate in EHS casualties. OBJECTIVE: Our aim was to determine the prehospital core cooling rate, need for continued cooling on arrival to the emergency department, and mortality rate associated with ice sheet use. METHODS: De-identified retrospective data were obtained from emergency medical services (EMS) and included presence or absence of altered mental status, cooling measures applied prior to EMS arrival, and time and core temperature (Tc; rectal) on-scene and on hospital arrival. Cooling rate was calculated from time and temperature data. Mortality data were obtained from the U.S. Army Combat Readiness Center. RESULTS: There were 462 casualties that met inclusion criteria. The cooling rate for the entire sample was 0.07°C ± 0.08°C · min-1. EHS casualties with an observed initial Tc < 39°C had an en route cooling rate of 0.03°C ± 0.04°C · min-1 vs. initial Tc ≥ 39°C cooling rate of 0.16°C ± 0.08°C · min-1. There was one fatality due to EHS, for a mortality rate of 0.20% (95% CI 0.01-1.20%). CONCLUSIONS: The cooling rate in EHS casualties with initial Tc ≥ 39°C was approximately double that reported in laboratory studies. The observed mortality rate was comparable with casualties treated with cold-water immersion. Our data suggest that ice sheets provide a viable alternative when practical constraints preclude cold-water immersion.

Exertional heat illness at Fort Benning, GA: Unique insights from the Army Heat Center.

The Army Heat Center at Fort Benning, GA was established to identify and disseminate best practices for the prevention, field care, evacuation, hospital care, and return to duty of exertional heat casualties. During the 2017-2021 surveillance period, there were 1,911 heat casualties treated at Ft. Benning's Martin Army Community Hospital. Most patients were junior enlisted and officer personnel who were engaged in initial entry training. Heat exhaustion, heat injury, heat stroke, and hyponatremia accounted for 52.6%, 18.4%, 18.2%, and 2.0% of total heat illnesses, respectively. The annual proportion of heat casualties that were due to heat exhaustion rose steadily during the surveillance period, reaching 77.7% in 2021, while the incidence of heat injury and heat stroke did not increase during this period. Data are presented on the occurrence of clusters of heat illness, the association of cases of heat stroke with arduous physical activities, and the seasonal variation in incidence of heat illnesses. It is important that unit leaders and trainers understand the risk factors for heat illness among those being trained and that early first aid measures be employed in the field (especially rapid cooling).

The Cardiometabolic Health Benefits of Sauna Exposure in Individuals with High-Stress Occupations. A Mechanistic Review.

Components of the metabolic syndrome (i.e., hypertension, insulin resistance, obesity, atherosclerosis) are a leading cause of death in the United States and result in low-grade chronic inflammation, excessive oxidative stress, and the eventual development of cardiometabolic diseases (CMD). High-stress occupations (HSO: firefighters, police, military personnel, first responders, etc.) increase the risk of developing CMD because they expose individuals to chronic and multiple stressors (i.e., sleep deprivation, poor nutrition habits, lack of physical activity, psychological stress). Interestingly, heat exposure and, more specifically, sauna bathing have been shown to improve multiple markers of CMD, potentially acting as hormetic stressors, at the cellular level and in the whole organism. Therefore, sauna bathing might be a practical and alternative intervention for disease prevention for individuals with HSO. The purpose of this review is to detail the mechanisms and pathways involved in the response to both acute and chronic sauna bathing and collectively present sauna bathing as a potential treatment, in addition to current standard of care, for mitigating CMD to both clinicians and individuals serving in HSO.