Correlations of serum potassium fluctuations with body temperature after major surgery.

We have observed an association between hypothermia and hypokalemia in a number of postoperative patients. In order to analyze the incidence and consequences of this correlation, 108 patients undergoing major operations were prospectively studied. Rectal temperature, serum and urinary potassium, arterial blood gases, blood glucose, and routine monitoring were analyzed. Hypothermia occurred in 35 (32%) patients, of whom 20 (57%) suffered from hypokalemia. Hypothermia was accompanied by an undercompensated metabolic acidosis in 15 (75%) and hyperglycemia in 18 (89%), while nine (45%) patients had cardiac dysrhythmias. Urinary potassium excretion was lower in hypothermic patients and therefore cannot explain the finding of hypokalemia. Administration of NaHCO3, insulin, digitalis, and calcium in patients suffering from hypothermia must be done with caution because hypokalemia may coexist with low body temperature and predispose the patients to lethal dysrhythmias.