Hypothermia and Associated Morbidities

Patients undergoing general and major conduction anesthesia will experience varying degrees of hypothermia with a typical core temperature loss of up to three degrees centigrade in the first three hours (figure 1). This is most pronounced during the first hour of anesthesia with a loss occurring of 1.6º C.1 Anesthetic-induced mild hypothermia (34-36° C) has documented ill effects, including a three-fold increase in surgical wound infections, a tripling of cardiac morbidity, coagulopathy, and prolonged emergence and recovery, all translating into longer hospital stays and increased costs. 2-6   The New England Journal of Medicine has reported that, “maintaining normothermia intraoperatively is likely to decrease the incidence of infectious complications in patients undergoing colorectal resection and to shorten their hospitalizations." 7

Due to these findings, the 2007 Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery8 include maintenance of normothermia as an evidence-based Level 1 guideline.9 In fact, the American Society of Anesthesiologists (ASA) has submitted maintenance of normothermia as a physician performance measure and is waiting for acceptance from the Centers for Medicare & Medicaid Services (CMS).9, 10

This is especially important since the American Medical Association signed the Joint House-Senate Working Agreement that promised to develop 140 performance measures covering 34 clinical areas and, by 2007, that physicians would voluntarily report three to five measures each. Each of these measures has significant bearing on the practice of anesthesia as governmental pressures mount to pursue value-based purchasing such as the Deficit Reduction Act and Tax Relief Act) and potential financial incentives like Pay-for-Performance.

Finally, hypothermia also appears to have a significant effect on patient satisfaction and anxiety. Memories of thermal comfort or discomfort during surgery have an effect on a patient’s overall satisfaction with surgical care. People respond holistically to complex stimuli, so the sensation of feeling cold produces discomfort and can trigger anxiety about the impending surgery, the anesthesia, expected pain and being immobilized.11    Nurses at the 2003 AORN Congress and the American Society of PeriAnesthesia Nurses convention cited patient warmth as the top comfort concern.11

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