The effect of 10 minutes of prewarming for prevention of inadvertent perioperative hypothermia: comparison with 30 minutes of prewarming

Background: At least 30 minutes of pre-warming has been recommended for the prevention of redistribution hypothermia. However, it has been reported that less than 30 minutes of pre-warming is also effective. The aim of this study was to evaluate the ability of 10 minutes of pre-warming to prevent inadvertent perioperative hypothermia. Results were compared with 30 minutes of pre-warming. Methods: In this prospective randomized study, 59 patients scheduled for elective surgery less than 120 minutes under general anesthesia were divided into 2 groups: the first group was pre-warmed for 10 minutes (n = 30), the second group for 30 minutes (n = 29). The patients were pre-warmed for 10 or 30 minutes in the pre-anesthetic area using a forced-air warmer. When the patients’ body temperatures decreased below 36°C, we warmed them with a forced-air warmer intraoperatively and postoperatively. Body temperatures were recorded during perioperative periods. Shivering and thermal comfort were evaluated in the pre-anesthetic area and post-anesthesia care unit. Results: The incidence of intraoperative and postoperative hypothermia were not significantly different (P > 0.05). However, the temperatures were higher in the 30 minute group from the post-warming time to 90 minutes after anesthetic induction (P < 0.05). Conclusions: Ten minutes of pre-warming has the same effectiveness as 30 minutes of pre-warming for preventing inadvertent perioperative hypothermia. It is a preferable choice for the patients scheduled for surgery less than 120 minutes under general anesthesia. Keywords: Forced-air warming; Perioperative hypothermia; Preoperative warming