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Accidental hypothermia and frostbite
In accidental hypothermia, grade severity by core temperature and consciousness, rewarm accordingly — passive, active external or active internal up to ECMO — and handle gently to avoid ventricular fibrillation; in a patient in cardiac arrest "nobody is dead until warm and dead".
Why it matters in the exam
Questions describe an older person found in a cold home, an intoxicated person found outdoors at night, or a victim rescued from cold water, and test the grade of severity, the ECG findings — bradycardia, the Osborn (J) wave and atrial fibrillation — and the right rewarming method. A mild patient shivers and is slightly confused; in moderate hypothermia shivering stops and consciousness falls; in severe hypothermia the patient is unconscious.
Resuscitation of a hypothermic patient follows different rules: below 30 °C give up to three shocks and withhold drugs until rewarmed above 30, and between 30 and 35 °C lengthen the interval between drug doses. A hypothermic patient in cardiac arrest is taken to a centre with ECMO, and a very high potassium (above 12 mmol/L) signals a hopeless prognosis. Avoid rough handling of a cold patient, which may trigger ventricular fibrillation.
Frostbite is also asked: rewarm the limb in water at 37–39 °C for 15–30 minutes, only when there is no risk of refreezing, without rubbing or heating by a fire. In severe injury presenting within about 24 hours, thrombolysis or iloprost is considered to save tissue. Amputation is usually delayed for weeks until the margin of dead tissue is clear — "frostbite in January, amputate in July".
Key points
- Grades: mild 32–35, moderate 28–32, severe below 28 °C.
- Rewarming by severity: passive, active external, active internal or ECMO.
- ECG: bradycardia, Osborn wave, atrial fibrillation.
- Cardiac arrest below 30 °C: up to three shocks, no drugs; "not dead until warm and dead".
- Frostbite: water at 37–39 °C, no rubbing, late amputation.
Summary table
| Grade | Core temperature | Picture | Rewarming |
|---|---|---|---|
| Mild | 32–35 °C | Shivering, mild confusion | Passive: remove wet clothes, blankets, a warm drink if fully conscious |
| Moderate | 28–32 °C | Shivering stops, falling consciousness, bradycardia | Active external: forced warm-air blankets, warmed fluids 38–42 °C |
| Severe | Below 28 °C | Unconscious, risk of VF | Active internal; unstable patient — ECMO |
| Cardiac arrest | Usually below 24 °C | Asystole or VF | Prolonged resuscitation, ECMO |
| Frostbite | — | White-grey skin, blisters | Water at 37–39 °C for 15–30 minutes; no rubbing |
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Sources
- European Resuscitation Council Guidelines: cardiac arrest in special circumstances, 2021 (with the 2025 update) — Accidental hypothermia
- Wilderness Medical Society Clinical Practice Guidelines for the out-of-hospital evaluation and treatment of accidental hypothermia and of frostbite, 2019 update — Rewarming and frostbite care
- Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 9th edition (2020) — Hypothermia; Frostbite and other localized cold injuries
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.