title: Intraoperative blood loss during orthognathic surgery is predicted by thromboelastography.
abstract: OBJECTIVE
  The aim of this prospective study was to evaluate the predictive value of the viscoelastic properties of whole blood samples collected preoperatively in relation to intraoperative blood loss in patients subjected to orthognathic surgery.
  
  
  METHODS
  Forty-one consecutive patients underwent simultaneous mandibular and maxillary osteotomy. Whole blood samples were collected preoperatively. The intraoperative blood loss volume was precisely estimated. The viscoelastic properties of whole blood samples were evaluated by thromboelastography (TEG), a global method that addresses the complex interplay among coagulation factors, blood platelets, and components of the fibrinolytic system. Blood platelet count, activated partial thromboplastin time, prothrombin time, plasma fibrinogen concentration, and D-dimer concentration were determined by routine methods.
  
  
  RESULTS
  Patients were separated into 2 groups according to their intraoperative bleeding volume (≤ 400 mL and >400 mL). No significant associations were observed between routine coagulation tests and intraoperative bleeding volume. The TEG results for the groups were compared. Significant associations were observed between intraoperative blood loss and the clot formation time, maximum clot firmness, and α angle, whereas bleeding volume was not related to the fibrinolytic resistance of the blood clot. An α angle exceeding 67° predicted with 95% certainty a blood loss of 400 mL or less.
  
  
  CONCLUSIONS
  We conclude that intraoperative bleeding volume in patients subjected to orthognathic surgery can be predicted by means of preoperative TEG analysis. TEG results provide optimization of patient safety and can be used for the evaluation of bleeding risk.
authors.affiliation: Unit for Thrombosis Research, Institute of Public Health, University of Southern Denmark, Esbjerg, Denmark. dmadsen@health.sdu.dk
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Madsen
authors.forename: Janne
authors.initials: J
authors.lastname: Ingerslev
authors.forename: Johannes J
authors.initials: JJ
authors.lastname: Sidelmann
authors.forename: Jens J
authors.initials: JJ
authors.lastname: Thorn
authors.forename: Jørgen
authors.initials: J
authors.lastname: Gram
mesh_terms: D000328:Adult; D016063:Blood Loss, Surgical / Q000706:statistics & numerical data*; D001809:Blood Viscosity / Q000502:physiology; D001810:Blood Volume / Q000502:physiology; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis; D005340:Fibrinogen / Q000032:analysis; D005544:Forecasting; D006801:Humans; D008297:Male; D063168:Mandibular Osteotomy / Q000379:methods; D063166:Maxillary Osteotomy / Q000379:methods; D056948:Orthognathic Surgical Procedures / Q000379:methods*; D019340:Osteotomy, Le Fort / Q000379:methods; D059229:Osteotomy, Sagittal Split Ramus / Q000379:methods; D010314:Partial Thromboplastin Time; D061214:Patient Safety; D010976:Platelet Count; D011237:Predictive Value of Tests; D011446:Prospective Studies; D055503:Protein Multimerization; D011517:Prothrombin Time; D018570:Risk Assessment; D013916:Thrombelastography / Q000379:methods*; D055815:Young Adult
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D; D005340:Fibrinogen