Guideline sources The following summarized guidelines for the evaluation and management of heat-related illness are prepared by our editorial team based on guidelines from the Wilderness Medical Society (WMS 2019). 1 Guidelines 1. Classification and risk stratification Risk assessment: use the wet-bulb globe temperature index for the assessment of heat risk. A Show 2 more 2. Diagnostic investigations Temperature measurement: Prefer rectal temperature measurement, when available, as the most accurate measurement of core hyperthermia compared to axillary, oral, or aural thermometry. B Do not delay empiric cooling for heat stroke by a measurement value that may be below the diagnostic threshold of 40 C in hyperthermic patients with an altered sensorium. D Screening for comorbidities: screen for significant preexisting medical conditions. B https://web.pathway.md/diseases/recbZqB6WmRb8jeJF 1/3 6/24/23, 12:31 PM Heat-related illness Pathway g p g g Cardiac evaluation: obtain cardiac evaluation in patients with recurrent episodes of heat syncope inconsistent with exercise-associated collapse or other clear explanation. B 3. Medical management Goals of cooling: cool patients with heat stroke to a target temperature of no less than 39 C. B Rehydration: Minimize dehydration in patients with heat illness. B Administer IV fluids for rehydration in patients with exertional heat stroke. B Intravenous cold fluids: Administer cold IV fluids as an adjunctive cooling method in patients with heat stroke. B Do not use intravascular cooling catheters or cold water lavage for primary treatment od patients with heat stroke. D Antipyretics: avoid using antipyretics in patients with heat illness. D Dantrolene: do not use dantrolene for the treatment of heat stroke. D 4. Nonpharmacologic interventions Passive cooling: offer passive cooling measures to minimize thermal strain and maximize heat loss. B Immersive cooling: offer cold water immersion as the optimal cooling method in the field management of patients with heat stroke. A Show 2 more Evaporative cooling: Consider offering evaporative or convective cooling as an adjunct cooling method in the field treatment if cold water immersion is unavailable. B Consider offering evaporative and convective cooling in classic heat stroke in the hospital setting. Do not use evaporative and convective cooling for exertional heat stroke, unless effective conductive cooling is not available. B Ice packs: apply ice packs to cover the entire body. Apply chemical cold packs, if used, to the cheeks, palms, and soles rather than the skin covering the major vessels. B 5. Preventative measures Acclimatization: advise allowing for acclimatization with 1-2 hours/day of heat-exposed exertion for at least 8 days. B Clothing: advise assessing and modifying clothing and equipment for a given activity as needed to optimize evaporative, convective, conductive, and radiative heat exchange or isolation, taking https://web.pathway.md/diseases/recbZqB6WmRb8jeJF 2/3 6/24/23, 12:31 PM Heat-related illness Pathway into account the mechanisms of heat accumulation or dissipation dominating during the activity. B Hydration: Ensure adequate hydration before activity. B Ensure ongoing rehydration with a "drink to thirst" approach sufficient to prevent > 2% loss of body weight. B Aerobic exercise: promote regular aerobic activity before heat exposure. B Avoidance of drugs affecting thermoregulation: advise minimizing the use of medications likely to affect the thermoregulatory response. B References 1. Grant S Lipman, Flavio G Gaudio, Kurt P Eifling et al. Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Heat Illness: 2019 Update. Wilderness Environ Med. 2019 Dec;30 4S S33 S46. Open 2. Lipman GS, Eifling KP, Ellis MA et al. Wilderness Medical Society Practice Guidelines for the Prevention and Treatment of Heat Illness. Wilderness Environ Med. 2014 Dec;25 4 Suppl):S55 65. Open https://web.pathway.md/diseases/recbZqB6WmRb8jeJF 3/3