The Annals of thoracic surgery
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Almost one-third of 24 adult patients undergoing hypothermic cardiopulmonary bypass (CPB) for elective cardiac operation were found to have upper extremity skin and muscle temperatures of 30.0 degrees C or less at termination of CPB despite the return of nasopharyngeal temperature to normal values. Within 45 minutes, the mean nasopharyngeal temperature of these patients fell spontaneously from 37.1 degrees +/- 0.3 degrees C (+/- standard deviation) to 35.1 degrees +/- 0.4 degrees C, a significantly greater fall (p less than 0.005) than was observed for patients with extremity temperatures greater than 30.0 degrees C. Persistent hypothermia of the upper extremities correlated statistically with large body mass; it appears that these patients incur disproportionately large caloric debts during hypothermic CPB. Inadvertent hypothermia after CPB can be minimized if both core and extremity temperatures are utilized to provide an assessment of the adequacy of warming prior to return to spontaneous circulation.
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Four instances of severe anaphylactoid reaction occurring subsequent to cardiopulmonary bypass are described. These catastrophic reactions, from which 2 patients died, took place approximately an hour following administration of protamine and were characterized by marked peripheral vasodilatation, loss of capillary membrane integrity, and fulminant noncardiogenic pulmonary edema. ⋯ Differential diagnosis from other causes of acute cardiorespiratory dysfunction depended on early assessment of pulmonary artery and left ventricular filling pressures, cardiac output, respiratory mechanics, and arterial blood gases. Therapy was difficult; success in 1 of the patients seemed to have been effected in part by prompt administration of high-dose corticosteroids and maintenance of peripheral vascular tone with an alpha-adrenergic agonist.