Self-warming blankets versus active warming by forced-air devices for preventing hypothermia: A systematic review and meta-analysis

Unintended perioperative hypothermia is a significant complication for patients undergoing anesthesia. Different measures are routinely undertaken to prevent hypothermia and its consequences. The evidence comparing the impact of self-warming blankets and forced-air warming is scarce. Therefore, this meta-analysis aimed to evaluate the efficacy of self-warming blankets compared to forced-air devices regarding the incidence of perioperative hypothermia. METHODS: We searched the Web of Science, Cochrane Central Register of Controlled Trials, PubMed, and Scopus for relevant studies from inception until December 2022. We included comparative studies with patients allocated to undergo warming using a self-warming blanket or forced air warming. All concerned outcomes were pooled as odds ratios or mean differences (MDs) in the meta-analysis models using Review Manager (RevMan version 5.4). RESULTS: Our results from 8 studies (597 patients) favored self-warming blankets over forced-air devices in terms of core temperature at 120 and 180 minutes after induction of general anesthesia (MD = 0.33, 95% confidence interval [CI] [0.14–0.51], P = .0006), (MD = 0.62, 95% CI [0.09–1.14], P = .02), respectively. However, the overall effect did not favor either of the 2 groups for the incidence of hypothermia (odds ratio = 0.69, 95% CI [0.18–2.62]). CONCLUSION: Ultimately, self-warming blankets have a more significant effect than forced-air warming systems in terms of maintaining normothermia of core temperature after induction anesthesia. However, the present evidence is not enough to verify the efficacy of the 2 warming techniques in the incidence of hypothermia. Further studies with large sample sizes are recommended.