From the Guidelines
Heat stroke is a severe medical emergency that requires immediate treatment with active cooling methods, and the most effective approach is cold-water immersion, as recommended by the Society of Critical Care Medicine guidelines 1.
Key Recommendations
- If you suspect heat stroke, call emergency services right away and move the person to a cooler location.
- Remove excess clothing and cool the body with cold water, ice packs on the neck, armpits, and groin, or immersion in cold water if possible.
- While waiting for help, have the person lie down with legs elevated, and offer cool water if they're conscious and able to drink.
Cooling Methods
- Active cooling methods are recommended over passive cooling in patients with heat stroke, with cold-water immersion being the most effective method 1.
- Other forms of active cooling, such as commercial ice packs, cold showers, ice sheets and towels, cooling vests and jackets, and evaporative, fanning, or a combination of techniques, can be used when water immersion is not available 1.
Prevention
- Prevention involves staying hydrated, wearing lightweight clothing, limiting outdoor activity during peak heat, and taking regular breaks in cool areas.
- Never leave anyone in a parked car, as temperatures can rise dangerously within minutes, even with windows cracked.
Risk Factors
- Risk factors for heat stroke include age extremes, certain medications, alcohol use, and lack of acclimatization to heat.
- Certain populations, such as infants, elderly, and people with pre-existing medical conditions, are at higher risk of heat stroke.
Treatment Goals
- The goal of treatment is to rapidly lower the body temperature to less than 39°C (102.2°F) and prevent long-term cognitive or motor dysfunction 1.
- Mortality rates in patients requiring ICU care for heat stroke can approach 60%, and approximately 30% of heat stroke survivors experience some form of long-term cognitive or motor dysfunction 1.
From the Research
Definition and Classification of Heat Stroke
- Heat stroke is an illness with a high risk of mortality or morbidity, which can occur in the young and fit (exertional heat stroke) as well as the elderly and infirm (nonexertional heat stroke) 2.
- It is characterized by hyperthermia (>40 °C/>104 °F) and nervous system dysregulation, with two primary etiologies: exertional and non-exertional 3.
- Heat stroke is classified into Non-Exertional Heatstroke (NEHS) and Exertional Heatstroke (EHS) 4.
Cooling Methods for Heat Stroke
- Rapid, effective cooling increases survival in heat stroke, but there is debate on the optimal cooling method 2.
- Ice-water immersion has been shown to be highly effective in exertional heat stroke, with a zero fatality rate in large case series of younger, fit patients 2.
- Evaporative plus convective cooling may be augmented by crushed ice or ice packs applied diffusely to the body, and chilled intravenous fluids may also supplement primary cooling 2.
- Water immersion of adults with exertional hyperthermia resulted in faster cooling rates when compared to passive cooling 3.
- Cold water immersion therapy is the most efficient and efficacious modality in treating heat stroke, yet it is rarely initiated in the prehospital setting 5.
Treatment and Management of Heat Stroke
- The basic principle of heatstroke management is early resuscitation and immediate cooling 4.
- Cold water immersion or convection evaporation method can be implemented based on the specific patient characteristic 4.
- Preventive strategies are early recognition by health workers, socialization to vulnerable groups, and adequate acclimatization 4.
- The prognosis of heat stroke in patients is directly related to the degree of hyperthermia and its duration, therefore rapid cooling is crucial 6.