Risk Factors for Postoperative Shivering After Oral and Maxillofacial Surgery

Purpose Postoperative shivering is a frequent complication of anesthesia. However, there are few reports about postoperative shivering in oral and maxillofacial surgery. Postoperative shivering in patients after osteotomy was observed from April 2008 to September 2015. This retrospective study investigated the risk factors of postoperative shivering in oral and maxillofacial surgery. Patients and Methods Anesthesia records of patients who underwent an osteotomy of the maxilla or mandible were checked. A patient's background (gender, age, height, and weight), anesthesia time, operative time, fentanyl, remifentanil, fluid volume, urine volume, blood loss volume, agent for anesthetic maintenance, rectal temperature at the end of surgery, and type of surgery were recorded in addition to the occurrence of postoperative shivering. In the univariate analysis, the Fisher exact test and the χ² test were used, and a multivariable analysis was performed using stepwise logistic regression to determine risk factors of postoperative shivering. Results In this study, 233 cases were investigated, and 24 patients (11.5%) had postoperative shivering. The occurrence of postoperative shivering was correlated with blood loss volume (shivering group, 633.9 ± 404.8 mL; nonshivering group, 367.0 ± 312.6 mL; P < .01) and core temperature at the end of surgery (shivering group, 37.2 ± 0.6°C; nonshivering group, 37.5 ± 0.5°C; P < .01). Two variables were associated with postoperative shivering. Rectal temperature at the end of surgery was the highest risk factor (odds ratio = 2.560277; 95% confidence interval, 1.236774-5.327362), and blood loss volume was the next highest risk factor (odds ratio = 0.997733; 95% confidence interval, 0.999-0998). Conclusion Clinicians should pay attention to postoperative shivering not only in patients with hypothermia but also in patients with substantial blood loss.