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As the cold and snow rips through the United States, hypothermia is a major concern because each year approximately 1,300 Americans die of hypothermia.
Classification of hypothermia:
- Mild (32-35 Celsius): shivering, hyperventilation, tachycardia, but patients are usually hemodynamically stable.
- Moderate (28-32 Celsius): CNS depression, hypoventilation, loss of shivering, risk of arrhythmias, and paradoxical undressing
- Severe (<28 degrees Celsius): increased risk of ventricular tachycardia/fibrillation, pulmonary edema, and coma
The risk of cardiac arrest increases when the core temperature is less than 32 Celsius and significantly rises when the temperature is less than 28 Celsius. Rapid rewarming is required as part of resuscitation should cardiac arrest occur.
A rescue therapy to consider (when available) is extra corporeal membrane oxygenation (ECMO). ECMO not only provides circulatory support for patients in cardiac arrest, but allows re-warming of patients by 8-12 Celsius per hour.
Some studies quote survival rates of 50% with hypothermic cardiac arrest patients receiving ECMO versus 10% in similar patients who do not receive ECMO.
As winter lingers in the United States, consider speaking to your cardiac surgeons now to plan an Emergency Department protocol for hypothermic patients that may require ECMO.
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