Rewarming in Hypothermia


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

Search Outcome:502


Relevant Papers:2

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.
References: YReferences

  1. Dae, M.W., Gao, D.W., Ursell, P.C. et al, Safety and efficacy of endovascular cooling and rewarming for induction and reversal of hypothermia in human-sized pigs. Stroke. 2003;34:734–738.
  1. Keller, E., Imhof, H.G., Gasser, S. et al, Endovascular cooling with heat exchange catheters: a new method to induce and maintain hypothermia. Intensive Care Med. 2003;29:939–943.
  1. Kjaergaard, B., Bach, P. Warming of patients with accidental hypothermia using warm water pleural lavage.Resuscitation. 2006;68:203–207.
  1. Walpoth, B.H., Walpoth-Aslan, B.N., Mattle, H.P. et al, Outcome of survivors of accidental deep hypothermia and circulatory arrest treated with extracorporeal blood warming. N Engl J Med. 1997;337:1500–1505.
  1. Tiruvoipati, R., Balasubramanian, S.K., Khoshbin, E. et al, Successful use of venovenous extracorporeal membrane oxygenation in accidental hypothermic cardiac arrest. ASAIO J. 2005;51:474–476.
  1. Willekes, T., Naunheim, R., Lasater, M. A novel method of intravascular temperature modulation to treat severe hypothermia. Emerg Med J. 2006;23:e56.
  1. Hypothermia After Cardiac Arrest Study Group. Mild therapeutic hypothermia to improve the neurologic outcome after cardiac arrest. N Engl J Med. 2002;346:549–556.
  1. Bernard, S.A., Gray, T.W., Buist, M.D. et al, Treatment of comatose survivors of out-of-hospital cardiac arrest with induced hypothermia. N Engl J Med. 2002;346:557–563.


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