Association Between Intraoperative Blood Loss Adjusted for Body Size and Postoperative Complication Risk After Hepatectomy: A Multicenter Retrospective Study.

BACKGROUND

While increased intraoperative blood loss (IBL) during hepatectomy has been associated with poorer surgical outcomes, variations in patient body size can obscure the impact of IBL on complications. This study aimed to clarify the relationship between body size-adjusted IBL and complications and to identify clinically relevant thresholds for IBL.

METHODS

A retrospective analysis was conducted using a multicenter database of 2,043 patients who underwent hepatectomy for hepatocellular carcinoma. IBL was adjusted by body size factors, including total blood volume (TBV). The IBL/TBV ratio, defined as the blood loss ratio (BLR), was identified as the optimal body size-adjusted marker based on the highest absolute |z|-statistic.

RESULTS

The AUROC for BLR (0.706) was slightly higher than that for unadjusted IBL (0.698), although the absolute improvement in discrimination was modest. In multivariable analysis incorporating operative complexity and calendar year, operative time and Albumin-Bilirubin score were significantly associated with severe postoperative complications. A significant interaction was observed between BLR and anatomical resection (AR) (P for interaction = 0.008), whereas the interaction between BLR and laparoscopic surgery was not statistically significant (P for interaction = 0.205). In the AR group, high BLR (cutoff 13.1%) was associated with a severe complication rate (CD ≥3) of 19.1%, compared with 6.5% for low BLR. In the non-AR group, complication rates were 25.0% for high BLR (cutoff 15.0%) and 4.0% for low BLR.

CONCLUSION

This study suggested that BLR may provide a clinically interpretable, body size-adjusted measure of intraoperative blood loss associated with postoperative complication risk. The association between BLR and severe postoperative complications differed according to anatomical resection status, supporting consideration of surgical context when interpreting BLR.