[Postanesthetic hematocrit changes in orthognathic surgery.]

Blood transfusions have been heavily questioned due to the increased number of transfusion-transmitted diseases This study aimed at evaluating perioperative blood loss and hematocrit recovery in 14 days, in patients submitted to orthognathic surgery under induced hypotensive anesthesia, with three different volume replacement techniques.

This was a prospective study of consecutive patients submitted to orthognathic surgery in the period August 1985 to July 2003. Patients were distributed in three groups: group I with pre-operative self-donation of blood 7 days before surgery; group II with intraoperative self-donation; and group III with normovolemic hemodilution. Pre-medication, induction, maintenance, drugs and monitoring were standardized. Patients were submitted to induced hypotensive general anesthesia. The following data were evaluated: blood loss, anesthetic length, systolic, diastolic and mean blood pressure, heart rate, hematocrit and hemoglobin at pre-induction, 60 hours after the first sample and at 14th the postoperative day, as well as perioperative complications.

Blood loss was 1340.03 +/- 427.97 in group I; 1098.08 +/- 429.30 in group II; and 1044.71 +/- 526.56 in group III, with statistical significance in group I as compared to groups II and III. There was significant decrease in pre-induction hemoglobin as compared to 60 hours and 83% hematocrit recovery in 14 days.

Perioperative blood loss for all groups was high, with need for allogeneic blood transfusion. Virtually all patients have tolerated blood loss since in general they were young patients, physical status ASA I and II without associated diseases. Hematocrit has not returned to preoperative values after 14 days.