Predictors of blood loss during orthognathic surgery: outcomes from a teaching institution

The objective of the study was to correlate different orthognathic surgical procedures with operating time and blood loss, reported from an accredited resident training institution.

Ninety-five patient records were evaluated retrospectively. Individual blood volume, percent blood volume lost (BVL), and estimated blood loss (EBL) for each patient were recorded and correlated with operating time (OT). Statistics included independent t tests, one-way analysis of variance, and linear regression.

The mean OT for all procedures was 203 min with mean blood loss 556 ml. Mean EBL for males was 676 ml versus 468 ml for females. Overall BVL was 12.4 %, while for males, BVL was 13.3 % compared to 11.8 % for females. For a single orthognathic procedure (n = 45), mean OT 145 min., EBL 414 ml, and BVL 9.0 %; two procedures (n = 41), mean OT was 239 min., EBL 659 ml, and BVL 15 %; three procedures (n = 9), mean OT 328 min, EBL 793 ml, and BVL was 17 %.

Examination of individual procedures suggests a shorter OT for Le Fort I procedures with slightly greater EBL. Concomitant orthognathic procedures are associated with greater OT and EBL. Blood volume should be calculated for male and female patients separately. Percent BVL can be predicted based on OT using a basic equation.