Clinical considerations in the use of forced-air warming blankets during orthognathic surgery to avoid postanesthetic shivering

Background: During head and neck surgery including orthognathic surgery, mild intraoperative hypothermia occurs frequently. Hypothermia is associated with postanesthetic shivering, which may increase the risk of other postoperative complications. To improve intraoperative thermoregulation, devices such as forced-air warming blankets can be applied. This study aimed to evaluate the effect of supplemental forced-air warming blankets in preventing postanesthetic shivering. Methods: This retrospective study included 113 patients who underwent orthognathic surgery between March and September 2015. According to the active warming method utilized during surgery, patients were divided into two groups: Group W (n = 55), circulating-water mattress; and Group F (n = 58), circulating-water mattress and forced-air warming blanket. Surgical notes and anesthesia and recovery room records were evaluated. Results: Initial axillary temperatures did not significantly differ between groups (Group $W=35.9{\pm}0.7^{\circ}C$, Group $F=35.8{\pm}0.6^{\circ}C$). However, at the end of surgery, the temperatures in Group W were significantly lower than those in Group F ($35.2{\pm}0.5^{\circ}C$ and $36.2{\pm}0.5^{\circ}C$, respectively, P = 0.04). The average body temperatures in Groups W and F were, respectively, $35.9{\pm}0.5^{\circ}C$ and $36.2{\pm}0.5^{\circ}C$ (P = 0.0001). In Group W, 24 patients (43.6%) experienced postanesthetic shivering, while in Group F, only 12 (20.7%) patients required treatment for postanesthetic shivering (P = 0.009, odds ratio = 0.333, 95% confidence interval: 0.147-0.772). Conclusions: Additional use of forced-air warming blankets in orthognathic surgery was superior in maintaining normothermia and reduced the incidence of postanesthetic shivering.