title: Risk Factors for Postoperative Shivering After Oral and Maxillofacial Surgery.
abstract: OBJECTIVE
  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.
  
  
  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 χ2test 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).
  
  
  CONCLUSIONS
  Clinicians should pay attention to postoperative shivering not only in patients with hypothermia but also in patients with substantial blood loss.
authors.affiliation: Assistant Professor, Department of Dental Anesthesiology, Kyushu University Hospital, Fukuoka, Japan. Electronic address: tsukamoto@dent.kyushu-u.ac.jp.
authors.forename: Masanori
authors.initials: M
authors.lastname: Tsukamoto
authors.affiliation: Assistant Professor, Department of Dental Anesthesiology, Faculty of Dental Science, Kyushu University Hospital, Fukuoka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Hitosugi
authors.affiliation: Resident, Department of Dental Anesthesiology, Kyushu University Hospital, Fukuoka, Japan.
authors.forename: Kanako
authors.initials: K
authors.lastname: Esaki
authors.affiliation: Professor, Department of Dental Anesthesiology, Faculty of Dental Science, Kyushu University Hospital, Fukuoka, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yokoyama
mesh_terms: D000328:Adult; D000758:Anesthesia / Q000009:adverse effects; D016063:Blood Loss, Surgical; D005260:Female; D006801:Humans; D007035:Hypothermia / Q000175:diagnosis / Q000209:etiology*; D016015:Logistic Models; D008297:Male; D063168:Mandibular Osteotomy; D063166:Maxillary Osteotomy; D015999:Multivariate Analysis; D011183:Postoperative Complications / Q000175:diagnosis / Q000209:etiology*; D012189:Retrospective Studies; D012307:Risk Factors; D012768:Shivering