Title: Active vs. Passive rewarming in Severe Accidental Hypothermia
Report By: Martin Hanazlek
Clinical Scenario: “A patient suffering from severe accidental hypothermia presents to EMS providers following falling through the lake ice while ice fishing and then snowmobiling for 20 min before collapsing at the trailhead parking lot shortly after calling 911. On assessment EMS providers find a 46 year old unresponsive male laying in the snow with a patent airway and shallow breathing at 9 breaths per min. The patient has a faint radial pulse palpated at a rate of 50 beats per min. The patient is gently moved into the back of the ambulance where EMS providers note an absence of shivering. Pt is placed on 100% oxygen via non-rebreather and attached to the cardiac monitor. The patent’s rectal temperature is 29C. SP02 is not easily obtainable or reliable since the patient has decreased distal circulation, sensation, and movement. Transport time for this patient is in excess of 60 min and air medical transport is unavailable. Will active rewarming to a body core temperature of 35 degrees C vs. passive rewarming result in observable afterdrop and / or increased patient survival?
PICO (Population – Intervention – Comparison – Outcome) Question:
In severe accidental hypothermia does active rewarming vs. Passive rewarming result in more or less adverse events for patients?
Search Strategy: (hypotherm*) AND (rewarming OR “active external rewarming” OR warming OR afterdrop OR heating) filters: humans and English. results: 2049
|Author, Date||Population:Sample characteristics||Design (LOE)||Outcomes||Results||strengths/ Weaknesses|
|Kornberger E. 1999||15 adult hypothermic patients||Case series||15 hypothermic patients successfully rewarmed above 35°C. Afterdrop not observed in any of the patients. 9 hypothermic patients had no prehospital cardiac arrest. all 9 had long-term survival. 6 patients had prehospital cardiac arrest which was not corrected.||Active rewarming showed no observable afterdrop and increased patient survival.||Flaws: small case studyStrength: good cohort selection|
|Laniewicz M. 2008||1 adult hypothermic patient||Case study||68-year-old female hypothermic (core temperature of 23.0 degrees C) unresponsive pulseless patient was successfully rewarmed above 35°C . Initial passive rewarming attempts failed before active rewarming iat a rate of 3°C per hour was initiated.||No afterdrop measured during rewarming process. Patient survived long term following active rewarming, and after patient failed initial traditional / passive rewarming methodologies.||Flaws: case study on singular patientStrength: applicable to EMS community|
Consider: Based on these results, active rewarming should remain part of the protocol when treating severe accidental hypothermia
Clinical Bottom Line: Active rewarming in patients presenting with severe accidental hypothermia improves patient outcome.
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