Efficacy of a novel warming blanket. Prospective randomized trial

Abstract

Perioperative hypothermia is a common complication of general anesthesia and occurs in up to 50 % of patients during ear, nose and throat (ENT) surgery. In this prospective, randomized controlled study the hypothesis that a new conductive warming blanket (BarrierA (R) EasyWarmA (R), Molnlycke Health Care Erkrath, Germany) is better in reducing the incidence of perioperative hypothermia in ENT surgery than insulation with a conventional hospital duvet alone was tested. After approval of the local ethics committee and written informed consent 80 patients with a planned procedure time between 1 and 3 h were recruited. Anesthesia was induced and maintained using propofol, remifentanil and rocuronium and the core temperature was measured using an esophageal temperature probe. Patients in the study group were warmed at least 30 min prior to induction of anesthesia using the novel warming blanket (BarrierA (R) EasyWarmA (R)) and patients in the control group were insulated with a standard hospital duvet. Data were tested using Fisher's exact test, Student's t-test or the Mann-Whitney U-test as appropriate. Time-dependent changes in core temperature were evaluated using repeated measures analysis of variance (ANOVA) and post hoc Scheff,'s test. Results are expressed as mean +/- SD or as median and interquartile range (IQR) as appropriate. A p < 0.05 was considered to be statistically significant. The ANOVA did not identify a significantly higher core temperature in the study group at any time point. Furthermore, Fisher's exact test showed no differences in the incidence of intraoperative (12 out of 29 versus 10 out of 32 patients, p = 0.44) or postoperative hypothermia (12 out of 29 versus 9 out of 32 patients, p = 0.30) between the groups. No adverse effects were observed. In the studied patient group the new conductive warming blanket (BarrierA (R) EasyWarmA (R)) showed no superiority compared to conventional thermal insulation alone.