Methods We enrolled 838 critically ill patients with euvolemia after initial treatment who had hemoglobin concentrations of less than 9.0 g per deciliter within 72 hours after admission to the intensive care unit and randomly assigned 418 patients to a restrictive strategy of transfusion, in which red cells were transfused if the hemoglobin concentration dropped below 7.0 g per deciliter and hemoglobin concentrations were maintained at 7.0 to 9.0 g per deciliter, and 420 patients to a liberal strategy, in which transfusions were given when the hemoglobin concentration fell below 10.0 g per deciliter and hemoglobin concentrations were maintained at 10.0 to 12.0 g per deciliter.

Results Overall, 30-day mortality was similar in the two groups (18.7 percent vs. 23.3 percent, P = 0.11). However, the rates were significantly lower with the restrictive transfusion strategy among patients who were less acutely ill - those with an Acute Physiology and Chronic Health Evaluation II score of less than or equal to 20 (8.7 percent in the restrictive-strategy group and 16.1 percent in the liberal-strategy group, P = 0.03) - and among patients who were less than 55 years of age (5.7 percent and 13.0 percent, respectively; P = 0.02), but not among patients with clinically significant cardiac disease (20.5 percent and 22.9 percent, respectively; P = 0.69). The mortality rate during hospitalization was significantly lower in the restrictive-strategy group (22.2 percent vs. 28.1 percent, P = 0.05).

Conclusions A restrictive strategy of red-cell transfusion is at least as effective as and possibly superior to a liberal transfusion strategy in critically ill patients, with the possible exception of patients with acute myocardial infarction and unstable angina. (N Engl J Med 1999;340:409-17) (C) 1999. Massachusetts Medical Society.