Exertional Heat Illness: Deployability, Risk Assessment, and Clinical Management

Nearly 2,500 active-duty service members suffered from heat-related ailments in 2016, despite policies, guidance and warnings that have been in place since 1955.1-9 Heat illnesses continue to be a significant threat to both the health of US military members and the effectiveness of military operations.1-2 It is a high priority to identify and manage heat-related injuries, including death, experienced by military service members when performing exertional tasks wearing impermeable personal protective equipment (PPE; e.g., Tyvek® clothing) during missions or disaster preparedness exercises 4,11. During a mission/exercise lasting several days or weeks, Homeland Response Forces (CERF-P/HRF) National Guard personnel perform under extreme environmental conditions. They may don PPE multiple times within a day and across days putting them at increased risk for exertional heat injury (EHI). This warrants continual medical monitoring for service member health and
safety.
Definitions of heat stress are robust in medical science, but few studies have examined predictive factors associated with EHI risk or the clinical management of EHI risk in military personnel. 15 At least eight EHI Risk Assessment Tools 11-14,17-20 or guidelines with varying recommendations for management of EHI risks exist.18-20 Authors of these guidelines and recommendations include NATO, Army, Airforce, and Centers for Disease Control. CERF-P/HRF teams utilize a SF-600 Overprint for Pre- and Post-Entry Assessment. The backside of this form used for re-entry assessment and monitoring of EHI during disaster exercises lacks information (e.g. environmental factors, hydration, etc.) needed to match established definitions for immediate and future EHI risk. There are no clinical management guidelines noted on the SF600.
An evidence-based approach for identifying, monitoring and predicting current and future EHI is critically needed to ensure the health and safety of 850,000 National Guard and Reserve Service Members and to assure efficient resource use.10 This study’s main objective is to expand the SF-600 used to determine deployability into an evidence-based tool that includes immediate EHI Severity (none, mild, low, moderate, high and death) and the Deployability Risk Score (low, moderate and high risk)17. The revised SF-600 (SF-600R) will also include evidence based practice guidelines for immediate treatment by medics and for management of future EHI risk for service members who don PPE multiple times. Our long-term goal is to protect the health of our service members and reduce EHI morbidity through clinical screening for EHI risk and early detection of EHI vulnerability. Our central premise is that EHI and EHI risk can be identified and ameliorated through the use of the SF-600R. The rationale underlying this proposed research is that the SF600R will provide a working tool to recogize immediate EHI episodes, and be able to provide documentation to score factors that may contribute to future EHI risk. There is a critical need to employ an evidence based tool that informs medics of potential EHI risks12 and provides pratical recommendations for managing heat injury and illness in the field. To test our central premise, we will pursue the following specific aims:
Aim 1. Revise the current SF-600 form to add missing heat risk data required to identify EHI Severity and the Deployability Risk Score and to incorporate current best practices around managing EHI risk.
Sub-aim 1a: Identify and prioritize factors related to EHI Severity and Deployability Risk through expert focus groups of medical personnel/CERF-P/HRF and other military experts. Experiences of
military medical personnel, and civilian experts actively engaged in treating National Guard personnel during disaster training exercises will identify missing critical components of EHI on the SF600 that is currently used as a deployability screening tool used in assessing personnel.
Sub-aim 1b: Revise the SF-600 form to include knowledge-based risk assessment of EHI Severity and Deployability Risk through a panel of content experts. Individuals with extensive EHI, medical, military or research expertise will establish the content validity of the revised tool.
Sub-aim 1c: Enhance the SF-600 form to include evidence based field and clinical management of heat injury and illness using a Delphi panel. Military personnel with medical, clinical and research
experience will provide professional expertise and valuable anecdotal knowledge about predictive factors, monitoring, and evaluation.
Aim 2. Pilot the revised SF-600 during disaster training exercises at two National Guard military bases in Washington and Texas. The U.S. Department of Defense supports the need to prevent EHI3 and identify specific risks for individual National Guard military members. Future work will evaluate the impact of clinical management recommendations added to the revised SF-600 for treating immediate EHI and future heat injury or illness. Establishing an accurate and effective risk-based tool with corresponding clinical management guidelines designed to be an adjunct to existing DoD EHI recognition and training protocols makes this project critically important for force health protection with application to other branches of the military.