Does Gender Affect Rectal Temperature Cooling Rates?: A Critically-Appraised Topic.

Clinical Scenario: Exertional heat stroke (EHS) is a medical emergency characterized by body core temperatures >40.5°C and central nervous system dysfunction.1 An EHS diagnosis should be immediately followed by cold-water immersion (CWI). Ideally, EHS victims cool at a rate >0.15°C/min until temperature reaches 38.9°C.1 While generally accepted, these EHS treatment recommendations often stem from research which only examined males. Since gender differences exist in anthropomorphics (e.g., body surface area, lean body mass)2 and anthropomorophics impact CWI cooling rates,3 it is possible CWI cooling rates may differ between genders.

CLINICAL QUESTION: Do CWI rectal temperature (Trec ) cooling rates differ between hyperthermic males and females?

SUMMARY OF FINDINGS: The average Trec cooling rate across all examined studies2,4,5 for males and females were 0.18±0.05°C/min and 0.24±0.03°C/min, respectively. Hyperthermic females cooled ~33% faster than males. Clinical Bottom Line: Hyperthermic females cooled faster than males most likely because of higher body surface area to mass ratios and less lean body mass.3 Regardless of gender, CWI is highly effective at lowering Trec . Clinicians must be able to treat all EHS victims, regardless of gender, with CWI given its high survival rate when implemented appropriately.5 Strength of Recommendation: Moderate evidence (two Level 3 studies) suggests females cool faster than males when treated with CWI following severe hyperthermia. Despite gender differences, cooling rates exceeded cooling rate recommendations for EHS victims (i.e., 0.15°C/min).6 .