title: A BMI >35 does not protect patients undergoing cardiac bypass surgery from red blood cell transfusion.
abstract: The effect of obesity on allogeneic intraoperative blood product transfusion in patients undergoing coronary artery bypass graft surgery (CABG) is poorly understood. We analyzed the influence of obesity on the risk of intraoperative red blood cell (RBC) transfusion among 45,200 consecutive non-reoperative CABG procedures from a multi-institutional perfusion database. A body mass index (BMI) in obese I category was associated with a 9.9% decrease in transfusion risk (p<0.05). Compared to patients with a normal BMI, obese I and obese III patients do not have any change in the relative risk of RBC transfusion. Overweight and mild obesity have a protective role in reducing intraoperative blood transfusion during cardiopulmonary bypass (CPB) surgery. However, logistic regression analysis showed that much of the observed reduction in transfusion rates for obese patients can be accounted for by other known confounds. The lack of a linear effect of increasing BMI on blood transfusion risk is a novel finding and warrants further investigation.
authors.affiliation: 1 Medical Department of Specialty Care, Nashville, TN, USA.
authors.forename: Linda B
authors.initials: LB
authors.lastname: Mongero
authors.affiliation: 1 Medical Department of Specialty Care, Nashville, TN, USA.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Tesdahl
authors.affiliation: 1 Medical Department of Specialty Care, Nashville, TN, USA.
authors.forename: Al H
authors.initials: AH
authors.lastname: Stammers
authors.affiliation: 2 Department of Cardiothoracic Surgery, Morristown Medical Center, Morristown, NJ, USA.
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Dickinson
authors.affiliation: 3 Department of Cardiovascular Sciences, Division of Cardiothoracic Surgery, East Carolina University, Greenville, NC, USA.
authors.forename: Alan P
authors.initials: AP
authors.lastname: Kypson
authors.affiliation: 1 Medical Department of Specialty Care, Nashville, TN, USA.
authors.forename: John
authors.initials: J
authors.lastname: Brown
authors.affiliation: 1 Medical Department of Specialty Care, Nashville, TN, USA.
authors.forename: Sam
authors.initials: S
authors.lastname: Weinstein
mesh_terms: D000368:Aged; D001804:Blood Transfusion, Autologous; D015992:Body Mass Index; D002315:Cardiopulmonary Bypass / Q000379:methods; D001026:Coronary Artery Bypass / Q000379:methods; D017707:Erythrocyte Transfusion; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D057725:Operative Blood Salvage; D012189:Retrospective Studies
keywords: BMI >35; cardiac surgery; cardiopulmonary bypass; obesity; obesity paradox; red blood cell transfusions