Synopsis
Distinguish life-threatening temperature illness from milder exposure, start effective thermal treatment, and adapt rescue and resuscitation to the environment.
- Heat stroke is a neurological emergency: confusion after exertion in the heat needs active cooling, even if the person is still sweating.
- Use core temperature to direct care; a peripheral thermometer can underestimate dangerous thermal disturbance.
- For suspected heat stroke, start effective available cooling immediately; cold-water immersion is preferred when it can be performed safely.
Reasoning priorities
Classify thermal severity and follow the response to cooling or rewarming.
Use a method appropriate to the setting, such as rectal temperature during exertional heat-stroke care or an appropriate low-reading probe in hypothermia. Record the measurement method alongside the value.
Worked reasoning
A runner collapses after a race, remains confused and has a rectal temperature of 40.5°C. The airway is patent and there is no major trauma; a supervised immersion bath is available.
- Recognise exertional heat stroke from the neurological change and exposure. Call emergency services, remove excess clothing and appoint someone to maintain the airway and observe the patient continuously.
- Start neck-down cold-water immersion without waiting for laboratory tests or transport. Keep the face clear of water and provide practical support so impaired consciousness does not create a drowning risk.
- Measure core temperature repeatedly while assessing breathing and circulation. Cooling brings the temperature to 38.8°C with improving cognition; reduce or stop immersion to avoid overshoot and continue clinical assessment.
- Verify sustained neurological and haemodynamic recovery and arrange hospital evaluation for renal, muscle, liver and clotting injury. A better temperature does not exclude evolving organ complications.
- Document collapse time, starting temperature, cooling method and response. Explain that further exertion is unsafe until medical assessment and a recovery plan are complete.
A person has hard numb toes but is conscious and haemodynamically stable after systemic assessment.
Key medicines
Adrenaline in hypothermic cardiac arrestUnder RCUK 2025, give 1 mg IV once core temperature reaches 30°C unless imminent ECPR is planned; use intervals of 6–10 minutes at 30–35°C. Return to standard ALS intervals after rewarming above this range.This modification applies to accidental hypothermic arrest, not a conscious cold patient with a pulse. Use core temperature and the specialist resuscitation plan; do not administer routine repeated doses below 30°C.
Amiodarone in hypothermic shockable arrestRCUK 2025 permits a 300 mg loading dose for a shockable rhythm under the arrest algorithm, but delays further amiodarone until core temperature exceeds 30°C.If VF persists after three shocks, defer further shocks until core temperature is above 30°C. Do not apply the drug or shock modifications to ordinary normothermic arrest.