Guidelines for RBC Transfusion Thresholds and Storage
What is the target hemoglobin level for red blood cell (RBC) transfusion among hospitalized adult patients who are hemodynamically stable, and the length of time RBCs should be stored prior to transfusion?
Reference librarians conducted a literature search for randomized clinical trials (RCTs) evaluating hemoglobin thresholds for RBC transfusion (1950-May 2016) and RBC storage duration (1948-May 2016) without language restrictions. The results were summarized using the Grading of Recommendations Assessment, Development, and Evaluation method. For RBC transfusion thresholds, 31 RCTs included 12,587 participants and compared restrictive thresholds (transfusion not indicated until the hemoglobin level is 7-8 g/dl) with liberal thresholds (transfusion not indicated until the hemoglobin level is 9-10 g/dl). For RBC storage duration, 13 RCTs included 5,515 participants randomly allocated to receive fresher blood or standard-issue blood.
The summary estimates across trials demonstrated that restrictive RBC transfusion thresholds were not associated with higher rates of adverse clinical outcomes, including 30-day mortality, myocardial infarction, cerebrovascular accident, rebleeding, pneumonia, or thromboembolism. The RCTs also demonstrated that fresher blood did not improve clinical outcomes.
The authors concluded that a restrictive transfusion threshold is safe in most clinical settings, and that the current blood banking practices of using standard-issue blood should be continued.
These guidelines suggest that it is good practice to consider the hemoglobin level, the overall clinical context, patient preferences, and alternative therapies when making transfusion decisions regarding an individual patient. The guidelines recommend that restrictive RBC transfusion threshold in which the transfusion is not indicated until the hemoglobin level is 7 g/dl is recommended for hospitalized adult patients who are hemodynamically stable, including critically ill patients, rather than when the hemoglobin level is 10 g/dl (strong recommendation, moderate quality evidence). A restrictive RBC transfusion threshold of 8 g/dl is recommended for patients undergoing orthopedic surgery, cardiac surgery, and those with pre-existing cardiovascular disease (strong recommendation, moderate quality evidence). The restrictive transfusion threshold of 7 g/dl is likely comparable with 8 g/dl, but RCT evidence is not available for all patient categories. These recommendations do not apply to patients with acute coronary syndrome, severe thrombocytopenia (patients treated for hematological or oncological reasons who are at risk of bleeding), and chronic transfusion–dependent anemia. Another recommendation is that patients, including neonates, should receive RBC units selected at any point within their licensed dating period (standard issue) rather than limiting patients to transfusion of only fresh (storage length: <10 days) RBC units (strong recommendation, moderate quality evidence).
Keywords: Acute Coronary Syndrome, Blood Transfusion, Cardiac Surgical Procedures, Critical Illness, Erythrocyte Transfusion, Hemoglobins, Hemorrhage, Myocardial Infarction, Pneumonia, Secondary Prevention, Stroke, Thromboembolism
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