According to this study:

* In stable children in the ICU, restricting the hemoglobin threshold for transfusion to 7 g/dL diminishes transfusion risk without increasing the rate of adverse events.

Up to half of children in the ICU are given a red blood cell transfusion to counter anemia and improve oxygen delivery. But leukocytes transfused along with the erythrocytes may promote inflammation and organ dysfunction. Because the optimal hemoglobin threshold for transfusion in stable, critically ill children is unknown, researchers compared the effects of limiting transfusion of packed red cells to patients with hemoglobin of 7 g/dL (restrictive strategy) as opposed to 9.5 g/dL (liberal strategy). The red-cell units transfused in both groups had had the leukocytes removed before storage in a process called universal leukocyte reduction.

Six hundred thirty-seven stable but critically ill patients three days to 14 years old at 19 tertiary-care ICUs in four countries were randomly assigned to one of two study groups, 320 in the restrictive-strategy group and 317 in the liberal-strategy group. All started with comparable hemoglobin values (a mean of 8 g/dL). Primary end points in both groups were the rate of deaths and of new cases of multiple-organ-dysfunction syndrome.

The hemoglobin transfusion target range in the restrictive-strategy group was 8.5 to 9.5 g/dL and in the liberal-strategy group was 11 to 12 g/dL. In both groups the transfusion of packed red cells began within 12 hours of achieving the transfusion threshold and was performed according to "a formula that accounted for the patient's weight and the average hemoglobin concentration in red-cell units at each participating site." The study protocol was followed for 28 days or until death, whichever came first, and could be suspended at the attending physician's discretion for reasons such as clinically significant blood loss, hemodynamic instability, severe hypoxemia, or surgical intervention and resumed when appropriate. The protocol was suspended in 39 patients in the restrictive-strategy group and in 20 in the liberal-strategy group.

Comparison of the two groups revealed no significant difference in either the number of patients with new or progressive multiple-organ dysfunction or in the number of deaths. The researchers wrote that "no significant differences were observed with respect to nosocomial infections, mechanical ventilation, the duration of stay in the ICU, or reactions to red-cell transfusion."

The authors conclude that in critically ill but stable children the use of a restrictive strategy involving a hemoglobin threshold of 7 g/dL for red-cell transfusion can safely reduce both the number of transfusions and the rate of exposure to red cells, thereby diminishing the chance of adverse outcomes of transfusion.

C. Contillo