Hypothermia

3 Jul

Defining hypothermia:

  • Mild hypothermia – Core temperature 32 to 35ºC (90 to 95ºF)
  • Moderate hypothermia – Core temperature 28 to 32ºC (82 to 90ºF)
  • Severe hypothermia – Core temperature below 28ºC (82ºF)

Exam findings:

  Mild hypothermia demonstrate tachypnea, tachycardia, initial hyperventilation, ataxia, dysarthria, impaired judgment, shivering, and so-called “cold diuresis.”

  Moderate hypothermia is characterized by proportionate reductions in pulse rate and cardiac output, hypoventilation, central nervous system depression, hyporeflexia, decreased renal blood flow, and loss of shivering. Paradoxical undressing may be observed. Atrial fibrillation, junctional bradycardia, and other arrhythmias can occur.

  Severe hypothermia can lead to pulmonary edema, oliguria, areflexia, coma, hypotension, bradycardia, ventricular arrhythmias (including ventricular fibrillation), and asystole

ECG Findings:

  • Prolongation of all intervals
  • Osborn waves

Care in the ED:

removing cold clothing, ABC’s, rewarming, and appropriate resuscitation. 

Core Temperature after-drop is a significant risk of active external rewarming.  As the patient is warmed, peripheral blood vessels dilate.

Ischemic, acidotic blood pooled in the extremities returns to the core circulation and can cause electrolyte disturbances (hyperkalemia, hypoglycemia), hypotension, and cardiac dysrhythmias.

Active core re-warming in association with external rewarming can help combat this.  Care is supportive, but the cardiovascular instability must be expected and properly monitored for.

Submitted by W. Brooks.

Reference(s): UpToDate; Cold stress, near drowning and accidental hypothermia: a review, Giesbrecht GG, Aviat Space Environ Med. 2000;71(7):733. picture

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One Response to “Hypothermia”

Trackbacks/Pingbacks

  1. therapeutic hypothermia: what’s the best way to get ‘em cold? « DAILYEM - September 26, 2012

    […] REMINDER WHY OVERSHOOTING PAST MILD HYPOTHERMIA (32 degrees C) IS BAD […]

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