EM Coach: It’s Cold Outside

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Treating a patient caught in snowstorm with dropping core temperature.



A 65-year-old male with a history of coronary artery disease presents to the emergency department after he and his mountaineering group were caught in a snowstorm. He is somnolent, but arousable and has a core temperature of 29°C.

His EKG is shown.

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Which of the following is the most appropriate next step in his treatment?

Question Answer Choices

  1. 40°C IV fluids
  2. Antiarrhythmic therapy
  3. Passive rewarming
  4. Percutaneous coronary intervention
  5. Thrombolytic therapy

Question Explanation

Correct answer: A. 40°C IV fluids


The case patient’s EKG shows an Osborn J wave. These may occur in patients with core temperatures below 32°C and can be mistaken for ST elevation.

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The J point on an EKG marks the end of the QRS and the beginning of the ST segment. When it is elevated with a hump configuration, this is referred to as an Osborn J wave. This may be seen in hypothermia, as well as hypercalcemia or Brugada syndrome. The wave does not require any specific cardiac intervention or antiarrhythmic therapy. Treatment should be directed at the underlying hypothermia.

Patients with moderate hypothermia (a core temperature between 28 and 32°C) should undergo active external rewarming with warmed parenteral fluids, a warm environment and forced-air blankets or heating pads. Minimally invasive rewarming (such as with bladder lavage) may also be considered.

Incorrect answer choices:

Antiarrhythmic therapy (Choice B) is not indicated in this hypothermic patient with slow atrial fibrillation and an Osborn J wave. Atrial fibrillation and flutter are fairly common in hypothermia and often resolve with rewarming.

Osborn J waves may be mistaken for ST segment elevation, particularly in this patient with a history of coronary artery disease. Treatment with thrombolytics (Choice E) or PCI (choice D) would be appropriate for a patient with ST elevation.

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In a hypothermic patient with ST elevation, it may be prudent to rewarm the patient prior to cardiac intervention, as cardiac instrumentation performed on an irritable ventricle may lead to life threatening arrhythmias. Expert consultation should be immediately obtained in such cases. The case patient, however, has a J wave — not ST elevation.

Passive rewarming (Choice C) is appropriate for alert, stable patients with mild hypothermia. This involves removing the patient from the cold environment, removing wet clothes and providing blankets to promote heat retention.

Drinking warm, sweet liquids is also encouraged (though this technically would be considered active rewarming). Active movement should be encouraged in patients without trauma or other contraindications. The case patient with moderate hypothermia requires more aggressive, active rewarming.



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