Prevention of Intraoperative Hypothermia by Preoperative Skin-Surface Warming

TLDR

Intraoperative hypothermia arises from anesthesia‑induced vasodilation and heat redistribution, and preinduction skin‑surface warming has been shown to reduce postinduction hypothermia in volunteers. In a randomized study of 16 total hip arthroplasty patients, those covered with a warming blanket for ≥90 min before induction were compared to those not warmed, with core and skin temperatures recorded throughout surgery. Prewarming reduced the first‑hour core temperature drop (−0.3 °C vs −0.7 °C), maintained higher core temperatures at surgery end (36.3 °C vs 35.2 °C), and eliminated postoperative shivering, demonstrating efficacy even for procedures lasting 3 h or longer.

Abstract

Intraoperative hypothermia initially results from internal redistribution of heat facilitated by anesthesia-induced vasodilation. Preinduction 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.Intraoperative core and mean skin temperatures were measured during total hip arthroplasty in 16 patients, randomly assigned to be covered preoperatively with a warming blanket for > or = 90 min (prewarmed group) or not covered (unwarmed group).During the first hour of anesthesia, core temperature decreased more than twice as much in the unwarmed group (-0.7 +/- 0.1 degree C; mean +/- SE) than in the prewarmed patients (-0.3 +/- 0.1 degree C). At the end of surgery, core temperature was 36.3 +/- 0.1 degree C in the prewarmed group and 35.2 +/- 0.2 degree C in the unwarmed group. During recovery, seven patients obviously shivered in the unwarmed group and none in the prewarmed group.Preanesthetic skin-surface warming reduces the initial postinduction hypothermia in surgical patients, preventing intraoperative hypothermia and postoperative shivering even for procedures lasting 3 h or longer.