Wearable and ingestible technology to evaluate and prevent exertional heat illness: A narrative review.

Exertional heat illness remains a constant threat to the athlete, military service member, and laborer. Recent increases in the number and intensity of environmental heat waves places these populations at an ever increasing risk and can be deadly if not recognized and treated rapidly. For this reason, it is extremely important for medical providers to guide athletes, service members, and laborers in the implementation of awareness, education, and measures to reduce or mitigate the risk of exertional heat illness. Within the past 2 decades, a variety of wearable technology options have become commercially available to track an estimation of core temperature, yet questions continue to emerge as to its use, effectiveness, and practicality in athletics, the military, and the workforce. There is a paucity of data on the accuracy of many of these newer devices in the setting of true heat stroke physiology, and it is important to avoid overreliance on new wearable technology. Further research and improvement of this technology are critical to identify accuracy in the diagnosis and prevention of EHI.

Incidence and Risk Factors for Bone Stress Injuries in United States Air Force Special Warfare Trainees.

OBJECTIVES: To determine (1) the incidence rate of lower extremity (LE) bone stress injuries (BSIs) in United States Air Force Special Warfare (AFSPECWAR) trainees during the first 120 days of training, and (2) factors associated with sustaining a LE BSI. DESIGN: Retrospective cohort study. METHODS: AFSPECWAR Airmen (n = 2,290, mean age = 23.7 ± 3.6 years) entering an intensive 8-week preparatory course "SW-Prep" between October 2017 and May 2021. We compared anthropometric measurements, previous musculoskeletal injury (MSKI), fitness measures, and prior high-impact sports participation in those that did and did not suffer a BSI during the 120-day observation period using independent t-tests and chi-square tests. A multivariable binary logistic regression was used to determine factors associated with suffering a BSI. RESULTS: A total of 124 AFSPECWAR trainees suffered a BSI during the surveillance period, yielding an incidence proportion of 5.41% and an incidence rate of 1.4 BSIs per 100 person-months. The multivariate logistic regression revealed that lower 2-minute sit-up scores, no prior history of participation in a high-impact high-school sport, and a history of prior LE MSKI were associated with suffering a BSI. A receiver operator characteristic curve analysis yielded an area under the curve (AUC) of 0.727. CONCLUSION: BSI incidence proportion for our sample was similar to those seen in other military settings. Military trainees without a history of high-impact sports participation who achieve lower scores on sit-ups tests and have a history of LE MSKI have a higher risk for developing a LE BSI during the first 120 days of AFSPECWAR training.

Heat stroke burden and validity of wearable-derived core temperature estimation during elite military training.

OBJECTIVES: Exertional heat stroke (EHS) remains a significant health concern while training in hot environments, prompting the development of noninvasive wearable technology for monitoring estimated core temperature (ECT). The objective of this study was to review the effectiveness of an ECT device during elite military training by providing a case series of individuals who developed EHS. METHODS: This is a retrospective study of EHS cases during high-intensity training while wearing the ECT device, Zephyr BioharnessTM. Data was collected from January 2021 through September 2021 at the Air Force Special Warfare Training pipeline in San Antonio, TX. Rectal temperatures of EHS diagnoses, defined by central nervous system (CNS) dysfunction and rectal temperature approaching or >40°C (104°F), were compared to ECT reading via Zephyr BioharnessTM. Incidence rates and psychometric properties were calculated using R package. RESULTS: A total of 47,058 daily peak ECT measurements were collected among 1,364 trainees. A total of 499 trainees flagged as potential EHS by Zephyr BioharnessTM reading >39.7°C (103.5°F). The incidence of confirmed EHS was 0.8/1000 person-months. Of the 10 confirmed EHS cases (9 males, 1 female; age = 23.4 ± 2.7 yrs; BMI = 25 ± 2; body fat = 13 ± 5%), 8 trainees had a peak ECT reading below 39.7°C which resulted in a sensitivity of 20%, specificity of 98.9%, positive likelihood ratio (LR) of 18.93 (95% Confidence Interval [CI] 5.5-65.6), and a negative LR of 0.81 (95% CI 0.6-1.1). CONCLUSION: ECT had substantial false positive and negative rates. Further studies are needed to validate this technology in other populations, and the algorithm used in this device needs to be refined to better capture the environmental and physical requirements in the special operations population.

Return to Duty Following Exertional Heat Stroke: A Review.

INTRODUCTION: Exertional heat stroke (EHS), which presents with extreme hyperthermia and alteration to the central nervous system, disproportionately affects the military, where warfighters are expected to perform in all types of environmental conditions. Because of an incomplete understanding of individualized recovery from EHS, there are several shortcomings with the current guidance on return to duty (RTD) following an EHS. The purpose of this manuscript is to provide an updated literature review of best practices for return to duty following EHS to guide decision making regarding EHS and explore areas of future research for medical staff who work with warfighters. MATERIALS AND METHODS: A literature review related to EHS in both athlete and military populations, as well as any existing guidelines for RTD, was conducted using PubMed and Covidence. RESULTS: Twenty-one articles were identified for this updated review on EHS and RTD, with recommendations focused during and after an EHS event, as well as the role of heat tolerance testing (HTT). CONCLUSIONS: EHS has a high morbidity and mortality rate if not treated rapidly. Because the extent of end-organ damage is dependent on the amount of time that the individual is hyperthermic, rapid diagnosis via rectal thermometry, and efficient cooling methods are imperative to the wellbeing of EHS patients. Following EHS, gradual RTD recommendations within the limits of operational demand should be implemented to reduce the risk for a subsequent heat injury event. While many versions of HTT, most notably the Israeli Defense Force (IDF) protocol, have been created to guide RTD recommendations, a universal assessment for heat tolerance has yet to be adopted. As such, medical personnel should apply a multifactorial approach to ensure safe RTD.

Management of a Special Warfare Trainee With Repeat Exertional Heat Stroke: A Case Study.

CONTEXT: Exertional heat stroke (EHS) is the most deadly form the exertional heat illness with a higher incidence among active duty US military members than in the general population. Current guidelines on EHS recovery timelines and return to duty vary among the military branches. In some cases, individuals experience prolonged heat and exercise intolerance with repeat exertional heat illness events, which can complicate the recovery process. Management and rehabilitation of such individuals is unclear. CASE PRESENTATION: This manuscript addresses the case and management of a US Air Force Special Warfare trainee who experienced 2 episodes of EHS, despite early recognition, gold standard treatment, and undergoing 4 weeks of a stepwise recovery after an initial EHS. MANAGEMENT AND OUTCOMES: After the second episode, a 3-step process was utilized, consisting of a prolonged and personalized recovery period, heat tolerance testing using Israeli Defense Force advanced modeling, and stepwise reacclimatization. This process allowed the trainee to successfully recover from repeat EHS and return to duty, and set a framework for future repeat EHS treatment guidelines. CONCLUSIONS: In individuals with repeat EHS, a prolonged recovery period followed by heat tolerance testing can be used to demonstrate appropriate thermotolerance and safely clear an individual to begin stepwise reacclimatization. Overall, patient care and military readiness may be improved by unified Department of Defense guidelines for return to duty after EHS.

COVID-19 Vaccination in a Military Population: Evaluation of a Quality Improvement Initiative to Increase Vaccine Confidence and Reduce Hesitancy.

INTRODUCTION: Extensive efforts have been directed toward developing an effective vaccine to fight against the Coronavirus Disease 2019 (COVID-19); however, hesitancy to receive COVID-19 vaccinations has become detrimental to overcoming the COVID-19 pandemic. Although the U.S. Military instated a COVID-19 vaccine mandate, some members were still hesitant to receive the vaccine. To determine the efficacy of a program focused on vaccine hesitation, a program evaluation was conducted on a COVID-19 vaccine educational intervention (hereafter COVID-19 Educational Presentation) for trainees at Lackland Air Force Base, TX, in September 2021. Objectives of the educational session included (1) determining the participants' level of confidence that the COVID-19 vaccines are safe and effective, (2) understanding the concern for long-term side effects from COVID-19 vaccinations, and (3) identifying the driving forces behind hesitancy to receive a COVID-19 vaccination. MATERIALS AND METHODS: We reviewed data collected from the COVID-19 Vaccine Educational Presentation; it consisted of a PowerPoint presentation addressing common questions and myths about COVID-19 vaccines. A survey instrument called the COVID-19 Hesitancy and Confidence Survey was created to assess attitudes to receive the COVID-19 vaccine. RESULTS: Two voluntary COVID-19 Educational Presentations were given in September 2, 2021, months prior to the Air Force's COVID-19 vaccine mandate deadline; 128 trainees participated in the assessment surveys. Overall, the educational intervention increased confidence to receive the COVID-19 vaccine increased by 12.6% (t = -7.928, P < 0.001). CONCLUSIONS: The COVID-19 Educational Presentation increased confidence and decreased hesitancy to receive the COVID-19 vaccine. Vaccine educational programs should continue in the military population to help combat misinformation and ensure that our military force is fully vaccinated and able to maintain mission readiness.

Response to a Serogroup B Meningococcal Disease Case Among Military Trainees.

We describe the public health response to a military trainee who developed serogroup B meningococcal disease while sharing underwater breathing equipment. Despite high transmission risk, with rapid isolation and postexposure prophylaxis administration, there were no secondary cases. This case supports carefully weighing serogroup B meningococcal vaccination in high-risk settings.

Using Virtual Visits to Care for Primary Care Patients With COVID-19 Symptoms.

PURPOSE: Examine use of office resources by primary care patients who were initially evaluated through telehealth, telephone, or in-person encounters. METHODS: Retrospective electronic health record review on patients seen in March 2020 for evaluation of potential COVID-19 symptoms, to assess the total number of interactions with physicians and office staff. RESULTS: Of 202 patients, 89 (44%) had initial telehealth, 55 (27%) telephone, and 52 (26%) in-person encounters. Patients initially evaluated through telehealth, telephone, and in-person encounters had a mean of 6.1 (S.D. = 3.7), 5.2 (S.D. = 3.6), and 4.5 (S.D. = 3.0) total interactions with the office, respectively (P = .03), and 9%, 12.7%, and 19.2%, respectively, had a subsequent in-person or emergency department visit (P = .22). Multivariable analysis showed no differences in number of office interactions based on initial visit type; older patients (95% CI = 0.00-0.07) and those with subjective fevers (95% CI = 1.01-3.01) or shortness of breath (95% CI = 0.23-2.28) had more interactions with the office. CONCLUSION: Primary care providers used virtual visits to care for most patients presenting with potential COVID-19 symptoms, with many patients choosing telephone over telehealth visits. Virtual visits can successfully limit patient exposure to other people, and consideration could be given to increasing its use for patients with potential symptoms of COVID-19.