Prospective observational study of the effectiveness of prewarming on perioperative hypothermia in surgical patients submitted to spinal anesthesia

Abstract

Prewarming has been shown to prevent intraoperative inadvertent hypothermia. Nevertheless, data about optimal prewarming-time from published clinical trials report contradictory results. We conducted this pilot study to evaluate routine clinical practice regarding prewarming and its effect on the prevalence of perioperative hypothermia in patients undergoing transurethral resection (TUR) under spinal anesthesia. This was a prospective, observational, pilot study to examine clinical practice in a tertiary hospital regarding prewarming in 140 consecutive patients. When prewarming (pw) was performed, forced-air warming was provided in the pre-anesthesia room for 15 (pw15), 30 (pw30), or 45 (pw45) min. Tympanic temperature was recorded upon entering the pre-anesthesia room, at the time of initiating surgery, and every 15 min intra-operatively. We also recorded duration of the surgical procedure and length of stay in the Post-Anesthesia Care Unit (PACU). Pw15 was performed in 34 patients, pw30 in 29 patients, and pw45 in 21 patients. Fifty-six patients did not receive pw and 96% of them developed hypothermia at the end of the surgical procedure, compared to 73% of patients in pw15 (p = 0.002), 75% in pw30 (p = 0.006) and 90% in pw45 (p = 0.3). Length of stay in the PACU was markedly shorter in pw15 (131 ± 69 min) and pw30 (123 ± 60 min) than in the non-pw group (197 ± 105 min) (p = 0.015 and p = 0.011, respectively). This difference was not significant in pw45 (129 ± 56 min) compared to non-pw patients. In conclusion, prewarming for 15 or 30 min before TUR under spinal anesthesia prevents development of hypothermia at the end of the surgical procedure.

Short-Periods of Pre-Warming in Laparoscopic Surgery. A Non-Randomized Clinical Trial Evaluating Current Clinical Practice

“…One of main reasons could be the prolonged surgical time and the increased heat loss via exposure to cold/dry CO 2 insufflation during pneumoperitoneum [ 23 ]. In non-laparoscopic surgeries, pre-warming for less than an hour has been shown to decrease the occurrence of intraoperative hypothermia [ 9 , 24 , 25 , 26 , 27 , 28 ]. However, few studies have examined the effect of pre-warming in laparoscopic surgery.…”

“…Core temperature was measured using a tympanic thermometer (Genius-2 Tympanic Thermometer and Base, Covidien Ltd., Mansfield, MA, USA) at hospital admission and upon arrival at the pre-anesthesia room (PreT). Prior to initiating the study, nurses-in-charge of temperature monitoring were trained for temperature measurements [ 9 ]. To reduce intra-observer variability, the mean value of three consecutive measurements was selected.…”

“…The sample size was estimated based on a previous observational study [ 9 ], with a power analysis to detect a difference of 0.3 °C in core temperature. Ninety patients ( n = 30 in each group) provided an 80% power for detecting a difference at an alpha-level of 0.05.…”

“…However, it has not been reported whether it could also decrease the rate of perioperative hypothermia when compared to an open approach [ 5 ]. Inadvertent hypothermia is common in the perioperative period, affecting 50–90% of patients undergoing surgery [ 6 , 7 , 8 , 9 ]. Perioperative hypothermia can increase intraoperative bleeding [ 10 ], surgical wound infection [ 11 ], discomfort, and length of hospital stay [ 12 ].…”

Incidence of Unintentional Intraoperative Hypothermia in Pediatric Scoliosis Surgery and Associated Preoperative Risk Factors

“…21 Prewarming using forced-air warming 7 devices is reportedly an effective method to prevent intraoperative hypothermia. [22][23][24] Horn et al performed a randomized controlled trial in patients (mostly adults) undergoing elective surgery under general anesthesia, including orthopedic surgery. They show significant differences in the change in core temperature between the patients who did and did not undergo prewarming.…”