Impact of Preoperative Hematocrit, Body Mass Index, and Red Cell Mass on Allogeneic Blood Product Usage in Adult Cardiac Surgical Patients: Report From a Statewide Quality Initiative

Objective: The study aims were to evaluate current blood transfusion practice in cardiac surgical patients and to explore associations between preoperative anemia, body mass index (BMI), red blood cell (RBC) mass, and allogeneic transfusion. Design: Multicenter retrospective study. Setting: Academic and non-academic centers. Participants and Interventions: After Institutional Review Board approval, 26,499 patients who underwent coronary artery bypass grafting +/- valve replacement/repair between 2011 and 2019 were included from the Maryland Cardiac Surgery Quality Initiative database. Patients were stratified into BMI categories (<25, 25 to <30, and >30 kg/m2), and a multivariable logistic regression model was fit to determine if preopera-tive hematocrit, BMI, and RBC mass were associated independently with allogeneic transfusion. Results: Preoperative anemia was found in 55.4%, and any transfusion was administered to 49.3% of the entire cohort. Females and older patients had lower BMI and RBC mass. Increased RBC and cryoprecipitate transfusions occurred more frequently after surgery in the lower BMI group. After adjustments, increased transfusion was associated with a BMI <25 relative to a BMI >30 at an odds ratio (OR) of 1.26 (95% confidence interval [CI]: 1.08-1.39). For each 1% increase in preoperative hematocrit, transfusion was decreased by 9% (OR: 0.91; 95% CI: 0.90-0.92). For every 500 mL increase in RBC mass, there was a 43% reduction of transfusion (OR: 0.57; 95% CI: 0.55-0.58). Conclusions: Transfusion probability modeling based on calculated RBC mass eliminated sex differences in transfusion risk based on preopera-tive hematocrit, and may better delineate which patients may benefit from more rigorous perioperative blood conservation strategy. (c) 2022 Elsevier Inc. All rights reserved.

Automated summary

The study aimed to evaluate blood transfusion practices in cardiac surgical patients and explore associations between preoperative anemia, BMI, RBC mass, and transfusion. Analysis of 26,499 patients showed that preoperative anemia was present in 55.4% of cases, with 49.3% receiving transfusions. Females and older patients had lower BMI and RBC mass, and lower BMI was associated with increased transfusion. Additionally, higher preoperative hematocrit and RBC mass were associated with decreased transfusion. The findings suggest that transfusion probability modeling based on calculated RBC mass could improve blood conservation strategies.