Incidence and Impact of a Single Red Blood Cell Transfusion: Analysis of the STS Database 2010-2019

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Background: As adverse effects of blood transfusions are better understood, recommendations support single red blood cell transfusions (SRBCT). However, an isolated SRBCT across the entire index admission, suggests even the single unit may be avoidable. We sought to identify the characteristics of cardiac surgery patients receiving an isolated SRBCT and analyze the impact on outcomes.

Methods: The Society of Thoracic Surgeons Adult Cardiac Surgery Database (STS-ACSD) was queried for the period between January 1, 2010 and December 31, 2019. Patients greater than 18 years of age undergoing isolated coronary artery bypass grafting (CABG) or isolated aortic valve replacement (AVR) were included. A total of 2,151,430 encounters were analyzed.

Results: Of the 847,442 (39.3%) of patients receiving any RBC transfusion during their index admission, 206,555 (24.4%) received only one unit. Propensity matching analysis determined SRBCT patients were significantly older (67.26 vs 64.02 yrs, OR 1.02; p < 0.001), female (39.1% vs 17.8%, OR 1.57; p < 0.001), non-Caucasian (18.2% vs 13.1%, OR 0.81; p < 0.001), and smaller body surface area (1.94 vs 2.07, OR 0.20; p < 0.001). They also had higher mortality (1.4% vs 1.0%, p < 0.001), stroke (1.7% vs 1.2%, p, 0.001), prolonged ventilation (6.4% vs 3.4 %, p<0.001), renal failure (1.8% vs. 0.9%, p<0.001), and reoperations (1.3% vs. 0.5%, p<0.001) than patients who received zero RBCs.

Conclusions: SRBCT is a common occurrence in adult cardiac surgery. This low volume transfusion is strongly associated with higher morbidity, even after controlling for pre-operative risk factors.

Keywords: Cardiac surgery; STS analysis; patient blood management; transfusion trends; transfusions.