#EMConf: Environmental Hypothermia

Hypothermia is a potentially life threatening condition seen more often in the winter seasons that has a spectrum of signs/symptoms and comes with a myriad of multiorgan dysfunction. It is essential for the EM physician to be cognizant of these and treat appropriately. 

Neurological - Altered mental status, poor judgement, ataxia, paradoxical undressing, loss of consciousness. At temperatures <29°C, pupillary reflex is abscent and <23°C corneal reflex is absent, which is not prognostic of brain death.

Cardiac - When temperatures drop <32°C, the myocardium become very irritated and can convert from bradycardia to atrial fibrillation/flutter with slow ventricular repsonse → ventricular fibrillation → asystole. Be careful placing a central line and go femoral as the guidewire alone can be enough to send this patient into a deadly arrhythmia

Metabolic - Cold diuresis often occurs so these patients will be volume down. Resuscitate them with warm fluids. Also check for rhabdomyolysis and possible compartment syndrome with increased CK.

Haematologic - Coagulopathy is profound even at temperatures <34°C. This becomes especially important in trauma. Make sure your patients are warmed to stop the bleeding!



Core Temp


Mild (HT I)

Conscious, shivering


Warm environment, warm clothing, blankets, sweet drinks

Moderate (HT II)

Impaired consciousness (may or may not be shivering)


Active external rewarming (bear hugger, warm fluids)

Cardiac monitoring

Minimal movement

Severe (HT III)

Unconscious, vital signs present


HT II management

Plus: airway management, consider ECMO


Vital signs absent

Cardiac arrest is possible below 32°C, much bigger risk <28°C


Up to 3 doses of epinephrine and defibrillation




Brown D. Hypothermia. In: Tintinalli JE, Stapczynski J, Ma O, Yealy DM, Meckler GD, Cline DM. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 8eNew York, NY: McGraw-Hill; 2016. http://accessemergencymedicine.mhmedical.com.ezproxy.rowan.edu/content.a.... Accessed January 03, 2019.