What are the treatment options for hypothermia?

Treatment of Hypothermia

Treatment of hypothermia should follow a tiered approach based on severity, with passive rewarming for mild cases, active external rewarming for moderate cases, and active internal rewarming for severe hypothermia. 1

Classification of Hypothermia

• Mild hypothermia: 35°C to 32°C (95°F to 89.6°F) 2
• Moderate hypothermia: 32°C to 28°C (89.6°F to 82.4°F) 2
• Severe hypothermia: <28°C (<82.4°F) 2
• Profound hypothermia: <24°C (75.2°F) 2

Treatment Algorithm Based on Severity

Mild Hypothermia (35°C to 32°C)

• Level 1 interventions (passive rewarming): 1

  • Remove wet clothing immediately 1
  • Increase environmental temperature 1
  • Apply warm blankets 1
  • Cover patient with vapor barrier to prevent heat loss 3
  • Monitor temperature every 15 minutes 1

• Patients with mild hypothermia and significant endogenous heat production from shivering can usually rewarm themselves with proper insulation, though active warming provides comfort and energy conservation 3

Moderate Hypothermia (32°C to 28°C)

• Level 2 interventions (active external rewarming): 1

  • Continue all Level 1 interventions 1
  • Apply heating pads 1
  • Use radiant heaters 1
  • Employ forced warm air blankets 1
  • Use electric blankets 1
  • Provide humidified oxygen 1
  • Monitor temperature every 5 minutes 1

• Active external rewarming has been shown to increase core temperature by approximately 0.8°C compared to a 0.4°C decrease with passive rewarming alone during transport 1

Severe Hypothermia (<28°C)

• Level 3 interventions (active internal rewarming): 1
  • Continue all Level 1 and 2 interventions 1
  • Administer warmed intravenous fluids 1
  • Consider peritoneal lavage with warmed fluids 1
  • For critical cases, consider extracorporeal rewarming methods: 1
    • Hemodialysis (can increase temperature by 2.15°C/hour) 4
    • Cardiopulmonary bypass (CPB) 1
    • Continuous arteriovenous rewarming (CAVR) 1
    • Heparin-free extracorporeal life support 1

Special Considerations

• Rewarming rate: Natural rewarming occurs at approximately 1.20°C/hour, while shivering can increase this rate up to 3.6°C/hour 1

• External rewarming in severe cases: Despite peripheral vasoconstriction in severe hypothermia, external rewarming can still be effective - one study showed patients with temperatures below 30°C were successfully warmed to above 35°C using forced-air warmers 1

• Rewarming target: Aim to rewarm to a minimum core temperature of 36°C before transferring patients between units, but cease rewarming after reaching 37°C as higher temperatures are associated with poor outcomes 1

• Caution with rewarming: Improper rewarming can potentially cause further injury through a "rewarming injury" phenomenon similar to reperfusion injury 5

• Monitoring during rewarming: Watch for complications including:

  • Cardiac arrhythmias (particularly atrial fibrillation) 2
  • Coagulopathy 2
  • Rhabdomyolysis 2

Prehospital Management

• Begin rewarming as early as possible in the prehospital setting 1
• Implement Level 1 strategies immediately, even if core temperature measurement isn't available 1
• Ensure all intravenous fluids are reliably warmed before infusion 3
• Early organized prehospital hypothermia protocols have been shown to reduce hypothermia incidence from 19% to 3% 1

Pitfalls and Caveats

• Temperature measurement: Always confirm diagnosis with core body temperature using a low-reading thermometer, as clinical presentation may not correlate with actual severity 2
• Overlooked condition: Hypothermia is often disregarded during initial resuscitation due to focus on other injuries - in one major trauma center, temperature was only documented in 38% of trauma admissions 1
• Prevention priority: Emphasis should be on prevention first and treatment second, as it becomes increasingly difficult to rewarm patients once significant heat is lost 1
• Cardiac assessment: Take extra time to check for life signs before initiating CPR in hypothermic patients 6
• Transport considerations: For severely hypothermic patients, consider transport to advanced care facilities even if transport time is greater 6