Is there a hidden blood loss in orthognathic surgery and should it be considered? Results of a prospective cohort study

The aim of this prospective observational study was to investigate the parameter ‘hidden blood loss’ (HBL) in context orthognathic surgery, incorporating undetected bleeding volumes occurring intra- and postoperatively. Orthognathic were recorded at three different time points. At end operation visible intraoperative loss (VBL) measured. Additionally, perioperative calculated 24 h 48 postoperatively using ‘haemoglobin balance method’. Analysis HBL based on difference between (CBL), determined after surgery. 82 patients (male 33, female 49) included study, whom 41 underwent bimaxillary surgery Bilateral Sagittal Split Osteotomy (BSSO). Statistically significant differences with reference absolute found when comparing two treatment modalities. In terms HBL, a volume 287.2 ml (±265.9) group 346.9 (±271.3) BSSO cohort recorded. This accounted for 32.2% (bimaxillary surgery) 62.6% (BSSO) CBL (BIMAX vs. BSSO, p < 0.001). is valuable adjunct record within management further improve patient safety postoperative outcomes.