Hypothermia

Follows exposure to cold, affects all body organs and systems when bodies core temperature falls below 35°C

  • Severe (core T less than 28°C) — unconscious, with or without vital signs, pupillary constriction reflex unreliable. Loss of reflexes
  • Moderate (core T 28–32°C) — drowsy, not shivering, may appear drunk or as if they had stroke
  • Mild (core T 32–35°C) — alert and shivering. Use passive rewarming

In severe hypothermia person may appear lifeless and mistakenly be pronounced dead. If in doubt — start and continue resuscitation. Evidence of death includes airway obstruction (eg vomit, snow, debris) or injuries incompatible with life

  • Severe hypothermia — high risk of ventricular fibrillation (VF)
    • Must be moved very gently, no sudden movements
    • Nurse flat, change position slowly, carefully
    • Cut away clothing, don't drag off
    • Follow usual emergency care procedures with very careful handling

Resuscitation considerations

  • Feel for carotid (neck) or femoral (groin) pulse for at least 30–45 seconds
  • Chest compressions and cardiac pacing not needed if you feel any pulse, no matter how slow, concentrate on rewarming person
  • Only indications for compressions are asystole (no heartbeat), VT
  • Once started, CPR must continue until return of circulation or death diagnosed
    • Circulation should return when core temp around 32°C
    • May take hours, needs huge commitment of resources and effort
  • Use 30 compressions and 2 breaths at rate of 100 compressions/minute
    • Do not give usual resuscitation (ALS) medicines until core T 30°C or more
    • When core T more than 32°C — standard resuscitation algorithms and decision making used
  • Defibrillation indicated for VT or VF
    • May not work if core Temp less than 32°C
    • Try once. If doesn't work — do not shock again until core T 30°C or more
    • Continue CPR

Do First

  • Stop further heat loss by removing wet clothing and pat dry gently
  • Have clinic room or ambulance uncomfortably warm
  • Put on dry clothing, wrap in dry blankets or sleeping bag and cover head
  • Put heat packs/covered hot water bottles under arms, on groin, abdomen and base of neck
  • If conscious give something sweet to drink

Check

  • Calculate age appropriate REWS
    • Adult — RR, O₂ sats (best centrally), pulse, BP, core Temp (best with low reading thermometer or probe)
    • OR Child (less than 13 years) — Respiratory distress, RR, O₂ sats (best centrally), pulse, central capillary refill time, core Temp (best with low reading thermometer or probe)
  • If not able to monitor core Temp — use history, clinical signs
    • Consider other causes, predisposing factors (eg sepsis, stroke)
  • Weight, BGL
  • U/A, pregnancy test
  • ECG and coma scale

Do

  • Give oxygen to target O2 sats 94–98% OR if moderate/severe COPD 88–92%
  • Put in IV cannula or Intraosseous needle
  • POC test potassium
  • Blood culture, FBC 
  • Give warm IV fluids to 43–45°C — microwave fluid for 3 minutes, testing temperature of the bag
    • normal saline — 250–500mL bolus
    • THEN  Normal saline with 5% glucose infusion — adult 150–200mL/hr OR match IV input with urine output
  • Put in indwelling urinary catheter – hourly urine measures — aim for 0.5mL/kg/hr
  • If any chance person long-term or regular heavy drinker of alcohol, or malnourished — give thiamine IV infusion — 100mg over 30 minutes