Procedure for assessing patients referred to the UK's military Heat Illness Clinic: a case series.

INTRODUCTION: The UK military operates a Heat Illness Clinic (HIC) to aid the return to exercise, training and occupational duty recommendations for individuals who have suffered exertional heat illness or heatstroke. This paper describes the process of assessment and reports representative data from n=22 patients referred to the HIC. METHOD: The assessment included clinical consultation, and measurement of maximal oxygen consumption (V̇O2max) and a heat tolerance test (HTT) conducted on a treadmill in an environmental chamber with an air temperature of 34°C and 44% relative humidity. Patients began the HTT wearing military clothing, carrying a rucksack (mass 15 kg) and walking at 60% V̇O2max, at 30 min the rucksack and jacket were removed and the T-shirt at 45 min, individuals continued walking for 60-90 min. Patients were considered heat tolerant if rectal temperature achieved a plateau. RESULTS: N=14 patients were heat tolerant on the first assessment and of the n=8 patients required to return for repeat assessment, five were heat tolerant on the second assessment and the remaining three on the third assessment. CONCLUSIONS: In conjunction with patient history and clinical evaluation, the HTT provides a physiological basis to assist with decisions concerning patient management and return to duty following an episode of heat illness.

Outcomes of UK military personnel treated with ice cold water immersion for exertional heat stroke.

INTRODUCTION: Despite mitigation efforts, exertional heat stroke (EHS) is known to occur in military personnel during training and operations. It has significant potential to cause preventable morbidity and mortality. International consensus from sports medicine organisations supports treating EHS with early rapid cooling by immersing the casualty in cold water. However, evidence remains sparse and the practice is not yet widespread in the UK. METHODS: Following changes to enable on-site ice cold water immersion (ICWI) at the Royal Marines Commando Training Centre, Lympstone, UK, we prospectively gathered data on 35 patients treated with ICWI over a 3-year period. These data included the incidence of adverse events (e.g. death, cardiac arrest or critical care admission) as the primary outcome. Basic anthropometric data, cooling rates achieved and biochemical and haematological test results on days 0-5 were also gathered and analysed. RESULTS: Despite being a cohort of patients in whom we might expect significant morbidity and mortality based on the severity of EHS at presentation, none experienced a serious adverse event. In this cohort with rapid initiation of effective cooling, biochemical derangement appeared less severe than that reported in previous studies. Higher body mass index (BMI) was associated with a lower cooling rate across a range of values previously reported as potentially of clinical significance. CONCLUSIONS: This case series supports recent updates to UK military guidance that ICWI should be more widely adopted for the treatment of EHS. Clinicians should be aware of likely patterns of blood test abnormalities in the days following EHS. Further work should seek to establish the impact of lower rates of cooling and develop strategies to optimise cooling in patients with higher BMI.

Neurological rehabilitation following heat illness in the UK Armed Forces.

Heat illness remains a significant threat to health in the UK Armed Forces despite recent improvements in the prevention of cases. A small number of heat illness survivors develop long-term neurological sequelae. Here we briefly review the background literature and present our experience of treating UK Armed Forces patients with neurological consequences of heat illness. In our cohort of patients, we observed significant improvements in subjective symptoms and objective assessments following a period of neurological rehabilitation at the Defence Medical Rehabilitation Centre. We conclude with recommendations for further research and for the incorporation of screening for neurological disability following heat illness into service policy.

Managing the risk of heat illness on board type 23 frigates deploying to the Arabian Gulf.

Temperature extremes are commonplace in the Middle East, varying between 30 degrees C and 50 degrees C. During the summer months, temperatures reach 50 degrees C consistently, with high humidity and sea temperatures rarely dropping below 33 degrees C. Sailing from the temperate climate of the U.K., Ship's crews are deploying to these extremes and working in spaces within the Ship where temperatures climb as high as 520C for at least 4 out of 6 months. Type 23 frigates (T23) were designed for anti-submarine warfare (anecdotally assumed to be North Sea based), yet now deploy continuously to hotter climates which subjects personnel to increased heat stress putting them at risk of heat injury. These risks can be minimised with simple measures such as maintaining hydration, rest periods outside of hot workspaces and finally cooling techniques such as inserting the arms up to the elbows in cool water for 10 minutes. During the 4 months spent in the Arabian Gulf of a 6 month tour, during the summer of 2010, personnel on board the T23 frigate HMS SOMERSET suffered no cases of heat illness despite the risks, due to employing these simple strategies.