[Significance of hemodynamic parameters of blood loss in orthognathic surgery]

The hemodynamic parameters of 95 patients undergoing maxillary or bimaxillary orthognathic surgery in 1996 and 1997 at the Department of OMF Surgery/Plastic Surgery, Krefeld, Germany, were analyzed retrospectivly to study the effect of intraoperative blood loss.

The parameters included the blood loss volume, age, weight and sex of the patients, the mode of osteotomy and the operation time, the surgeon, the average blood pressure, the infusion volume, the anesthesiologist, the thrombocyte counts and their function, the activity of the coagulation factors II, V, VII, VIII, IX, X, XI, XII, XIII and von-Willebrand-factor, and the pathological coagulation factor counts of each patient, the rate of autologous blood donation and the rate of retransfusion. Statistical analysis was done using the Speraman-Rhotest.

The average blood loss during maxillary osteotomy was 670 +/- 380 ml and during bimaxillary surgery 1120 +/- 510 ml. Men lost about 300 ml more than women. Operations of more than 3.5 h in length led to a blood loss of 1200 +/- 520 ml as opposed to 670 +/- 310 ml. The average blood loss among various surgeons was between 670 ml and 1180 ml of various anesthesiologists between 730 ml and 1200 ml, without statistical evidence. Some 17.9% of patients showed pathological thrombocytic function concerning medication with aspirin; 34.7% had pathological activities of coagulation factors, but only 2.1% with clinical significance.

Mode of operation, maxillary or bimaxillary, und length of operation were the most significant factors of intraoperative blood loss. Patients with pathological coagulation had nearly the same rate of blood loss as patients with physiological coagulation. In most cases this was determined by restriction of aspirin. Analysis of the rate of autologous blood retransfusion showed a significant correlation to blood loss in bimaxillary surgery. Maxillary osteotomy led to a retransfusion of only 14.2% of autologous blood unit. This should be reviewed critically especially concerning costs.