Widespread interest in the complications associated with packed red blood cell (PRBC) transfusions has led to the scrutiny of traditional transfusion practices. Recently, attempts have been made to define more clearly the indications for PRBC transfusions in patients, particularly those who are critically ill. At present, however, transfusions continue to be ordered based on a hemoglobin level less than 10 g/dL. We report herein the impact on oxygen consumption of PRBC transfusions administered for a hemoglobin concentration less than 10 g/dL in 30 surgical intensive care unit patients who were euvolemic and hemodynamically stable. For the group as a whole, transfusion had a negligible effect on oxygen consumption. Fifty-eight percent of all such transfusions failed to change oxygen consumption by greater than 10% and could therefore be considered of questionable benefit.