Exertional heat stroke (EHS) is a medical emergency which, if left untreated, can result in death. The standard of care for EHS patients includes confirmation of hyperthermia via rectal temperature (Trec) and then immediate cold-water immersion (CWI). While CWI is the fastest way to reduce Trec, it may be difficult to lower and maintain water bath temperature in the recommended ranges (1.7°C–15°C [35°F–59°F]) because of limited access to ice and/or the bath being exposed to high ambient temperatures for long periods of time. Determining if Trec cooling rates are acceptable (ie, >0.08°C/min) when significantly hyperthermic humans are immersed in temperate water (ie, ≥20°C [68°F]) has applications for how EHS patients are treated in the field.
Are Trec cooling rates acceptable (≥0.08°C/min) when significantly hyperthermic humans are immersed in temperate water?
Summary of Findings:
Trec cooling rates of hyperthermic humans immersed in temperate water (≥20°C [68°F]) ranged from 0.06°C/min to 0.19°C/min. The average Trec cooling rate for all examined studies was 0.11±0.06°C/min.
Clinical Bottom Line:
Temperature water immersion (TWI) provides acceptable (ie, >0.08°C/min) Trec cooling rates for hyperthermic humans post-exercise. However, CWI cooling rates are higher and should be used if feasible (eg, access to ice, shaded treatment areas).
Strength of Recommendation:
The majority of evidence (eg, Level 2 studies with PEDro scores ≥5) suggests TWI provides acceptable, though not ideal, Trec cooling. If possible, CWI should be used instead of TWI in EHS scenarios.