Background

The effects of extreme environmental heat on the health and performance of the warfighter have been documented for centuries.^1,2 The U.S. military has conducted and supported research aimed at reducing the impact of heat stress since World War II, greatly advancing our understanding of the physiology of heat stress, the pathophysiology of exertional heat illness (EHI), and the associated epidemiology and risk factors.^3–5 However, weather is an established mission variable and the warfighter needs to be prepared to conduct operations and training in adverse environmental conditions.⁶ The combination of environmental heat and/or high metabolic heat production coupled with clothing and equipment factors practically guarantees that EHI casualties will occur. As detailed in this issue of the MSMR, EHI, hyponatremia, and rhabdomyolysis continue to affect individual warfighters and pose a significant burden on the military medical system.

In June 2016, a soldier died of hyponatremia during Ranger School training.⁷ This was the eighth death due to hyponatremia or exertional heat stroke at Fort Benning since 1998 and illustrates what has been termed the "tragedy loop". ⁸ In other words, when such a death occurs, there is renewed interest in prevention through education and training as well as in the medical management of EHI casualties. That response is usually effective, but, with the passage of time, there is a loss of institutional memory as experienced leaders and trainers are reassigned and replaced by less experienced personnel. This loss may culminate in another death, and the cycle would begin anew. With 1 exception, all of the heat illness–related deaths at Fort Benning in the past 22 years have illustrated that the tragedy loop follows a 2- to 3-year time course.⁸

In the wake of the most recent death, clinicians at Martin Army Community Hospital (MACH) recognized that a more sustainable approach was necessary to break the tragedy loop and to prevent future deaths due to heat illness. In 2017, Fort Benning hosted the first "Heat Forum", which brought together clinicians, researchers, and leaders from across the Army. At the same time, an ad hoc "Heat Center" was created, consisting of a group of dedicated clinicians and other health care professionals who focused their efforts on improving prevention efforts, standardizing medical management, and facilitating research. Ultimately, the participants realized that this ad hoc approach was not sustainable, as it depended on busy clinicians being able to devote time outside their clinical responsibilities. In 2019, with the support of leaders at the Army Office of the Surgeon General, Regional Health Command-Atlantic, and the Consortium for Health and Military Performance (CHAMP) at the Uniformed Services University of the Health Sciences (USUHS), the Warrior Heat- and Exertion-Related Event Collaborative (WHEC) and the Fort Benning Heat Center were created. The fourth annual Heat Forum took place that same year, and the meeting has expanded to include attendees and participants from across the Department of Defense (DOD).

The WHEC is a joint service, multidisciplinary executive advisory board composed of representatives from CHAMP, the U.S. Army Research Institute of Environmental Medicine (USARIEM), the Army Public Health Center (APHC), the Army Training and Doctrine Command, the Departments of the Navy and the Air Force, and selected civilian institutions. A key issue is the lack of coordination and synchronization of policies and procedures not only between the services, but also between installations within a given service. An objective of the WHEC will be to develop clinical practice guidelines that reflect the best evidence for preventing, mitigating, risk stratifying, and improving the management of EHI and related illnesses in warfighters. Importantly, the WHEC will maintain a web-based repository of clinical practice guidelines, information papers, and an "ask the expert" function to assist in providing up-to-date information to address prevention, mitigation, and return-to-duty concerns. The WHEC website can be accessed at https://www.hprc-online.org/resources-partners/whec.

The WHEC will also provide guidance and leadership, assist in coordinating and facilitating research, and collaborate with service-specific research centers, including the Heat Center at Fort Benning. The Army Surgeon General's Office tasking was simply to do all possible to decrease the morbidity and mortality of EHI and related conditions and end the aforementioned tragedy loop.

For each of the last 4 years, owing in part to the total number of trainees, the environmental conditions, and the physical demands of training, Fort Benning has experienced the highest numbers of EHIs of any installation in the DOD, so positioning the first field operating agency Heat Center at Fort Benning was a logical decision.⁹ Three areas of focus of the Heat Center have been identified—prevention, medical management, and research.

Prevention is the foundation of the Center’s efforts. Through the annual Heat Forum, senior leader engagements, and the training of leaders and cadre down to the level of sergeants and staff sergeants, Heat Center staff provide education and training to support prevention efforts. A current initiative of the Heat Center is the creation and inclusion of EHI prevention training for all cadre and drill sergeants during their inprocessing and instructor orientation at Fort Benning. As heat illness treatment is often not covered in medical curricula, education of new MACH staff supports the medical management line of effort.

Over the years, MACH staff have refined treatment protocols for the medical management of EHI casualties. The other services, in particular the Navy in support of Marine Corps training, have also developed unique and successful strategies for the management of EHI and related conditions. The WHEC aims to share these protocols, from point of injury through return to duty, with all installations and services. The goal is to coordinate best practices across the DOD to mitigate EHI and related conditions across the DOD. The WHEC, leveraging clinical consultation in the National Capital Region and across the U.S., will activate and commission a clinical consultation hotline to assist with challenging EHI case decisions.

Lastly, while USARIEM, USUHS, and the APHC have a long history of exceptional laboratory-based and epidemiological research on the effects of heat stress on the warfighter, because of a lack of access to heat casualty patients, they have been limited in their ability to conduct clinically meaningful research on this population. Given the sheer volume of EHI casualties at Fort Benning, active research collaborations between the Heat Center, USUHS, USARIEM, and the U.S. Army Medical Material Development Agency have been established.

Given the demands of military training, it is an unrealistic goal to prevent all EHI in the military. To be prepared to fight anywhere, the warfighter must be trained in a range of conditions, including hot environments. The WHEC and the Heat Center are ideally positioned to support efforts to reduce the severity of EHI as much as possible and to eliminate all heat-related deaths in the military and end the tragedy loop.

Author affiliations: Martin Army Community Hospital, Fort Benning, GA (MAJ DeGroot); the Uniformed Services University of the Health Sciences, Bethesda, MD (Dr. O’Connor).

References

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