Effectiveness of cutaneous warming systems on temperature control: Meta-analysis

Aim: This paper is a report of a meta-analysis to identify the effectiveness of different types of cutaneous warming systems in temperature control for patients undergoing elective surgery. Background: Hypothermia is a common and serious complication of surgery. Different cutaneous warming systems are used to prevent hypothermia during surgery but there have been no previous meta-analyses of the effectiveness of different warming systems in controlling temperature. Data sources: We conducted a search of the CINAHL (2000 to April 2009), Medline (2000 to April 2009), Embase (2000 to April 2009) and the Cochrane Register of Controlled Trials (2000 to April 2009) databases for randomized controlled trials published in English, Spanish and Portuguese. The primary outcome measure of interest was core body temperature. Methods: A systematic review incorporating meta-analysis was carried out. Results: From 329 papers, 23 trials compared warming systems. Forced-air warming systems had a strong tendency towards superior temperature control over passive insulation via cotton blankets (mean difference: 0·29°C; 95% confidence interval: -0·02 to 0·59, three trials 292 patients) and radiant warming systems (mean difference: 0·16°C; 95% confidence interval: -0·01 to 0·33, three trials, 161 patients). However, circulating water garments tended to be more effective than forced-air warming systems (mean difference: -0·73°C; 95% confidence interval: -1·51 to 0·05, I² = 97%; four trials, 198 patients). Pooled results approached statistical significance and indicated clinically meaningful differences in temperature control. Conclusion: Current evidence suggests that circulating water garments offer better temperature control than forced-air warming systems, and both are more effective than passive warming devices.