Effects of preoperative warming on the occurrence of surgical site infection: A systematic review and meta-analysis

OBJECTIVE: To determine whether preoperative warming can reduce the risk of surgical site infection (SSI) after surgery. BACKGROUND: Intraoperative hypothermia is a risk factor for the occurrence of SSI in patients after surgery. However, the effectiveness of preoperative warming in reducing the incidence of the condition remains unclear. MATERIALS AND METHODS: A systematic review was conducted using Medline, EMBASE, and the Cochrane Library to identify randomized controlled trials (RCTs) that evaluated the risk of SSI after surgery with and without the use of a preoperative warming protocol. The primary outcome measure was the diagnosis of SSI within 10-90 days of surgery. The pooled risk ratio was estimated with a fixed-effect meta-analysis. Sensitivity analyses were performed to examine the impact of the structural design of preoperative warming on the pooled risk of SSI. RESULTS: Of the 249 studies identified, seven RCTs representing 1086 patients were included in the present meta-analysis. The use of preoperative warming was associated with a significant decrease in SSI (RR = 0.60, 95% CI 0.42-0.87, P = 0.072). Specifically, we defined patients who used forced-air warming (FAW) and integrated measures such as liquid heating and warming blankets as the MIX group and patients who used only FAW as the FAW group. Patients who used MIX methods (temperature set <43 °C and 30-min prewarming) before surgery benefited more from prewarming. CONCLUSIONS: The results of this study suggest that preoperative warming can reduce rates of SSI after surgery. We, therefore, recommend the application of MIX warming methods before surgery.