The effect of short time periods of pre‐operative warming in the prevention of peri‐operative hypothermia

Abstract

SummaryThe aim of our study was to evaluate the performance of different durations of active pre-operative skin-surface warming (pre-warming) to prevent peri-operative hypothermia and postoperative shivering. We randomly assigned 200 patients, scheduled for surgery of 30-90 min under general anaesthesia, to receive passive insulation or forced-air skin surface warming for 10, 20 or 30 min. Body temperature was measured at the tympanic membrane. Shivering was graded by visual inspection. There were significant differences in changes of core temperature between the nonpre-warmed group and all the pre-warmed groups (p < 0.00001), but none between the three pre-warmed groups (p = 0.54). Without pre-warming, 38/55 (69%) patients became hypothermic (< 36°C) at the end of anaesthesia, whereas only 7 ⁄ 52 (13%), 3 ⁄ 43 (7%) and 3 ⁄ 50 (6%) patients following 10, 20 or 30 min pre-warming, respectively, became hypothermic (p < 0.001 vs no pre-warming). Shivering was observed in 10 patients without, and in three, three and one patients with pre-warming in the respective groups (p = 0.02). Pre-warming of patients for only 10 or 20 min before general anaesthesia mostly prevents hypothermia and reduces shivering.

Effect of short-term prewarming on body temperature in arthroscopic shoulder surgery

“…Although some experiments have 13 (52) 12 ( revealed that 30 minutes of prewarming is needed to gain heat content exceeding the amount of redistribution [14], another study has shown that prewarming for 20 minutes can reduce the risk of perioperative hypothermia [18]. Jo et al [19] have conducted controlled trial and found that prewarming for 20 minutes cannot reduce the incidence of intraoperative hypothermia.…”

Peri‐operative warming devices: performance and clinical application

“…Prewarming before induction of anaesthesia is the only technique that has been shown to attenuate redistributive heat loss. The maximal effect takes 2 h to achieve [100], although periods as short as 10 min have a significant effect [101]. The optimal combination of practicality and effectiveness has yet to be determined.…”

Perioperative temperature measurement and management: moving beyond the Surgical Care Improvement Project

“…This strategy has been shown to significantly attenuate, and prevent, hypothermia from redistribution of blood from the patient's core to periphery while under general anesthesia [71][72][73][74][75]. Recently, prewarming the patient for as little as 10 to 20 minutes has been shown as effective at reducing perioperative hypothermia and postoperative shivering [75]. Disadvantages with preoperative warming include reduced efficacy with sweating and patient discomfort [72,75].…”

“…Recently, prewarming the patient for as little as 10 to 20 minutes has been shown as effective at reducing perioperative hypothermia and postoperative shivering [75]. Disadvantages with preoperative warming include reduced efficacy with sweating and patient discomfort [72,75]. The Artic Sun™ Temperature Management System (Medivance Inc., Louisville, CO) has been shown "to be more effective for rewarming patients after off-pump coronary artery bypass than conventional warming methods. "…”