title: Factors that determine intraoperative blood loss in bimaxillary osteotomies and the need for preoperative blood preparation.
abstract: OBJECTIVE
  To define factors that influence blood loss in bimaxillary osteotomies and the need for blood preparation at the Faculty of Dentistry, Mahidol University, Bangkok, Thailand.
  
  
  METHODS
  We retrospectively studied 208 patients who underwent bimaxillary osteotomies during 2005 to 2009. Possible factors for intraoperative blood loss such as age, body weight, gender, operative time, experience of the surgeons, and different operative procedures were statistically analyzed.
  
  
  RESULTS
  Female patients had a significantly higher percentage of blood loss from allowable blood loss than male patients (P = .006). Experience of the surgeons had a significant influence on blood loss (P = .02) and operative time (P < .001). No significant difference in blood loss was found among the 4 groups classified by operation (P = .852). Simple regression analysis showed a significantly positive correlation between blood loss and duration of operation (R(2) = 0.15, P < .001). There was no correlation between blood loss and patient age (P = .35).
  
  
  CONCLUSIONS
  The factors that influence blood loss include patient gender, experience of the surgeon, and operative time. Blood preparation should be considered in women, especially small individuals in whom a long operative time is expected and who are being operated on by an inexperienced surgeon. Because of the low rate of transfusion, a group-and-save policy is appropriate.
authors: Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Mahidol University, Rajavithavi, Bangkok, Thailand.
authors: Duangdee
authors: D
authors: Rummasak
authors: Benjamas
authors: B
authors: Apipan
authors: Pariya
authors: P
authors: Kaewpradup
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D016063:Blood Loss, Surgical; D001803:Blood Transfusion; D001804:Blood Transfusion, Autologous; D001835:Body Weight; D005260:Female; D005500:Follow-Up Studies; D006400:Hematocrit; D006801:Humans; D008297:Male; D008334:Mandible / Q000601:surgery; D008437:Maxilla / Q000601:surgery; D056948:Orthognathic Surgical Procedures / Q000379:methods*; D010027:Osteotomy / Q000379:methods*; D019340:Osteotomy, Le Fort / Q000379:methods; D059229:Osteotomy, Sagittal Split Ramus / Q000379:methods; D011300:Preoperative Care; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D013997:Time Factors; D055815:Young Adult