While a restrictive transfusion strategy has been advocated for most patients, a restrictive approach for cardiac surgery patients may put them at a greater risk of anemia-induced tissue hypoxia or worse outcomes. A recent multicenter, randomized trial published in The New England Journal of Medicine compared a restrictive threshold (transfuse when hemoglobin drops below 7.5 g/dL) to a liberal threshold for RBC transfusion (transfuse when hemoglobin drops below 9.5 g/dL in operating room or ICU or less than 8.5 g/dL otherwise) among 5243 cardiac surgery patients. Patients in the restrictive group were less likely to receive a transfusion and received fewer units on average than patients in the liberal group. Mortality, however, was similar in both groups—3.0% of patients died in the restrictive group compared to 3.6% in the liberal group (odds ratio, 0.85; 95% CI, 0.62 to 1.16). The non-inferiority of a restrictive approach to a liberal approach was robust even when considering myocardial infarctions, strokes, new-onset renal failure events in addition to death (11.4% vs 12.5%, odds ratio 0.90; 95% CI, 0.76 to 1.07; P<0.001 for non-inferiority). A restrictive approach to transfusions for cardiac surgery patients appears to be safe.
- Mazer CD, Whitlock RP, Fergusson DA, et al. Restrictive or liberal red-cell transfusion for cardiac surgery. The New England Journal of Medicine 2017; published online November 12, 2017. doi:10.1056/NEJMoa1711818