Hi all, winter is coming,
The above patient is brought into Resus 52 by EMS as a notification for both a stroke and STEMI. You aren't able to a history as he appears obtunded, and you obtain the following EKG.
An Osborn wave (late delta wave, J-wave) is a characteristic (but not pathognomonic) finding of hypothermia at temperatures lower than 32C. It is a positive deflection at the J-point (between QRS complex and ST segment) most prominent in the precordial leads. There is correlation with the degree of hypothermia and the magnitude of the osborn wave which resolves with rewarming. Other situations this can occur are hypercalcemia, neurological injury, certain medications, and as a normal finding. Other EKG findings in hypothermia are shivering artifact, bradycardia, and prolonged PR, QRS, ST segments.
Mild hypothermia (32-35C) presents as shivering and some drowsiness. In these patients, initiate passive external rewarming measures (warm blankets).
Moderate hypothermia (28-32C) presents as loss of shivering and progressive lethargy. Vitals signs begin to be affected with a drop in HR and cardiac output.
Severe hypothermia (<28C) presents with coma and severely depressed cardiopulmonary function. Arrhythmias and cardiac arrest (a-fib, v-fib, asystole) start to occur at this point as well. Rewarming may be needed to achieve ROSC. For moderate and severe hypothermia, you'll want to use active external rewarming (Bair Hugger) and active internal rewarming. For the latter, methods include warm IV fluids, warmed humidified air, bladder lavage, gastric lavage. On the more extreme side you could also do peritoneal lavage, pleural lavage, or ECMO (most rapid rewarming technique).
(subtle resolution of J wave)
Sources
LIFTL, Osborn Wave; lifeinthefastlane.com/ecg-library/basics/osborn-wave-j-wave/
Smith, Steve Osborn waves and hypothermia. hqmeded-ecg.blogspot.com/2011/11/osborn-waves-and-hypothermia.html
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