Association of Preoperative Hematocrit and Intraoperative/Postoperative Transfusion Volume With Outcomes of Major Abdominal Surgery

Abstract

Background

Despite the independent effect of lower preoperative hematocrit levels and higher transfusion volumes with increased postoperative morbidity and mortality, the impact of the interplay between these variables on outcomes remains poorly understood. We hypothesized that after adjusting for preoperative hematocrit, red cell transfusions exhibit a stepwise association with increased mortality and complications after major abdominal surgery (MAS).

Methods

All adults (≥18 years) undergoing elective MAS (colectomy, enterectomy, proctectomy, laparotomy, splenectomy, gastrectomy, enterorrhaphy/colorrhaphy, and peritoneal drainage) were identified in the 2020-2022 American College of Surgeons National Surgical Quality Improvement Program database. The primary outcome of interest was in-hospital mortality within 30 days of discharge. Secondary outcomes included postoperative complications, as well as length of stay (LOS) and unplanned readmission.

Results

Among 15,646 patients undergoing MAS, 88.0% were not transfused, while 5.3% received 1 unit and 6.7% received ≥2 units of blood. After multivariable adjustment, lower preoperative hematocrit levels (AOR 0.9, 95% Cl 0.9-1.0) and higher transfusion volumes (1 Unit: AOR 1.6, 95% Cl 1.1-2.4; ≥2 Unit: AOR 2.4, 95% Cl 1.6-3.4) were independently associated with an increased risk of mortality (all P < 0.05). Notably, higher transfusion volumes demonstrated a stronger association with increased rates of individual complications, prolonged LOS, and unplanned readmission compared to preoperative hematocrit levels (all P < 0.05).

Discussion

Given the independent impact of transfusion volume on acute outcomes, efforts should focus on early, multimodal anemia management to reduce transfusion requirements in the preoperative phase, rather than relying on intraoperative transfusions, when feasible.