Intraoperative hypothermia initially results from internal redistribution of heat facilitated by anesthesia-induced vasodilatlon. Preinductlon skin-surface warming minimizes postinduction hypothermia in anesthetized volunteers. However, its efficacy might be reduced in surgical situations, because of multiple sources of heat loss.Methods:
Intraoperative core and mean skin temperatures were measured during total hip arthroplasty in 16 patients, randomly assigned to be covered preoperatlvely with a warming blanket for ≥90 min (prewarmed group) or not covered (unwarmed group).Results:
During the first hour of anesthesia, core temperature decreased more than twice as much in the unwarmed group (−0.7 ± 0.1° C; mean ± SE) than in the prewarmed patients (−0.3 ± 0.1° C). At the end of surgery, core temperature was 36.3 ± 0.1° C in the prewarmed group and 35.2 ± 0.2° C in the unwarmed group. During recovery, seven patients obviously shivered in the unwarmed group and none in the prewarmed group.Conclusions:
Preanesthetic skin-surface warming reduces the initial postinductlon hypothermia in surgical patients, preventing intraoperative hypothermia and postoperative shivering even for procedures lasting 3 h or longer.