Blood transfusion in cardiac surgeries - Toward a personalized protocol

Protocols for allogeneic red blood cell (RBC) transfusion are often operationalized using a universal, static hemoglobin (HGB) threshold, even though HGB varies across the population, being strongly correlated with sex, environment, and other medical conditions. 1 Carson J.L. Stanworth S.J. Roubinian N. et al. Transfusion thresholds and other strategies for guiding allogeneic red blood cell transfusion. Cochrane Database Syst Rev. 2016; 10: CD002042 PubMed Google Scholar ,2 Murphy W.G. The sex difference in haemoglobin levels in adults - mechanisms, causes, and consequences. Blood Rev. 2014; 28: 41-47 Crossref PubMed Google Scholar In 1942, Adams and Lundy proposed a static threshold that has become known as the “10/30 rule” – transfuse when the hemoglobin is below 10g/dL or hematocrit below 30% - prior to anesthetic induction. 3 Adams R.C.L.J. Anesthesia in cases of poor surgical risk: some suggestions for decreasing the risk. Anesthesiology. 1942; 3: 603-607 Crossref Google Scholar Subsequently, randomized clinical trials comparing liberal (10.0 g/dL) vs. restrictive thresholds (7–8 g/dL) verified sufficient oxygen carrying capacity with HGB below 10 g/dL without having a negative impact on mortality. Consequently, leveraging the empirical results of these randomized trials, modern surgical and anesthesia task force recommendations have focused on static, one-size-fits-all transfusion triggers, 4 Ducrocq G. Gonzalez-Juanatey J.R. Puymirat E. et al. Effect of a restrictive vs liberal blood transfusion strategy on major cardiovascular events among patients with acute myocardial infarction and anemia: the REALITY randomized clinical trial. JAMA. 2021; 325: 552-560 Crossref PubMed Scopus (78) Google Scholar including the 2021 STS/SCA/AmSECT/SABM updated patient blood management guidelines. 5 Tibi P. McClure R.S. Huang J. et al. STS/SCA/AmSECT/SABM update to the clinical practice guidelines on patient blood management. Ann Thorac Surg. 2021; 112: 981-1004 Abstract Full Text Full Text PDF PubMed Google Scholar However, transfusion policies utilizing a static, one-size-fits-all threshold may overlook individual characteristics that correlate with patients’ HGB level and result in unnecessary transfusions for patients.