Tuesday, 13 August 2013

The potential danger in treating Hypothermia-induced Hypokalemia

The post from Veeraish earlier this week reminded me of this patient who demonstrated 

an important learning point regarding hypokalemia in hypothermic patients. A 75 year old 

woman was found unconscious in her unheated home with overnight temperatures of 

-1⁰C. On arrival at the Emergency Department, her core rectal temperature was a 

staggering 21⁰C, blood pressure 90/50 and pulse was 28 beats per minute. EKG was 

classic, demonstrating slow atrial fibrillation, wide T wave inversion and the characteristic 

J waves of hypothermia (see Figure; note that the depth of the J wave inflection 

correlates with the degree of hypothermia). Laboratory values included  serum potassium 

Her renal function was normal. After some initial warming, repeat potassium was 1.6 

mmol/L and her heart rate improved. When she had been warmed to 26⁰C, the serum 

potassium corrected to 5.1 mmol/L before settling at 3.6 mmol/L (with no potassium 

supplementation). Her serum phosphorous level and blood sugars normalized when her 

body temperature rose above 30⁰C. She also spontaneously converted to sinus rhythm. 

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