Abstract

This is an observational study of heat-related illness in UK Service Personnel deployed into summer conditions in Northern Kuwait and Southern Iraq. Among 622 hospitalisations reported during a 9-week period at the historical British Military Hospital, Shaibah, 303 consecutive admissions are reviewed in detail. Several clinical syndromes attributable to thermal stress were observed. These ranged from self-limiting debility to life-threatening failures of homeostasis, with 5.0% developing a critical care requirement. Hyponatraemia was a commonly occurring electrolyte disturbance by which, relative to the local reference range, a majority of heat-attributed admissions were affected. Reductions in measured serum sodium could be profound (<125 mmol/L in 20.1% of all heat-related casualties). Hypokalaemia was observed in half of cases, though only a minority were affected by severely low potassium (<2.5 mmol/L in 4.0%). Despite preventive measures prescribed on hospital discharge, illness and significant biochemical derangements could recur upon return to duties in the heat. We reiterate the need for primary prevention of heat illness wherever possible and importance of early, effective interventions to treat and protect Service Personnel from secondary injury. We also highlight the requirement for comprehensive assessment to inform prognostication and occupational decision-making in relation to extreme climatic heat, including aeromedical evacuation. We draw additional attention to the contribution of psychological factors in select cases and identify research questions to improve understanding of environment-induced incapacitation in general.