Red Blood Cell Transfusions and Erythropoietin Therapy

Chapter 464 Red Blood Cell Transfusions and Erythropoietin Therapy

Red blood cells (RBCs) are transfused to increase the oxygen-carrying capacity of the blood and, in turn, to maintain satisfactory tissue oxygenation. Guidelines for RBC transfusions in children and adolescents are similar to those for adults (see Table 464-1 on the Nelson Textbook of Pediatrics website at www.expertconsult.com). However, transfusions may be given more stringently to children, because normal hemoglobin levels are lower in healthy children than in adults and, often, children do not have the underlying multiorgan, cardiorespiratory, and vascular diseases that develop with aging in adults. Thus, children often compensate better for RBC loss and, as is true for patients of all ages, there is increasing enthusiasm for conservative practices (i.e., low pre-transfusion hematocrit values).

In the perioperative period, it is unnecessary for most children to maintain hemoglobin levels of 8 g/dL or greater, a level frequently desired for adults. There should be a compelling reason to prescribe any postoperative RBC transfusion, such as continued bleeding with hemodynamic instability, because most children (without continued bleeding) can, over time, restore their RBC mass with iron therapy. The most important measures in the treatments of acute hemorrhage are to control the hemorrhage and to restore the circulating blood volume and tissue perfusion with crystalloid and/or colloid solutions. If the estimated blood loss is > 25% of the circulating blood volume (>17 mL/kg) and the patient’s condition remains unstable, RBC transfusions may be indicated along with plasma transfusions at a 1 : 1 ratio of RBC : plasma volumes. In acutely ill children with severe pulmonary disease requiring assisted ventilation, it is common practice to maintain the hemoglobin level close to the normal range, although the efficacy of this practice has not been documented by controlled scientific studies.

The pre-transfusion blood hemoglobin level or hematocrit that should prompt a RBC transfusion is controversial (i.e., restricted or a low pre-transfusion level vs liberal or a high pre-transfusion level) despite a substantial amount of published information, including randomized clinical trials. Some physicians in critical care settings prefer to transfuse RBCs quite conservatively (i.e., restricted guidelines) and to permit modest anemia, because patients with levels close to the normal range (i.e., liberal guidelines) have poorer outcomes. Studies in critically ill adults demonstrated better outcomes when the hemoglobin level was maintained at 7-9 g/dL than at 10-12 g/dL. However, anemic adults with significant cardiac disease did better with hemoglobin levels maintained at 13 g/dL than at 10 g/dL. Similar studies in children admitted to intensive care units found no inferiority when RBC transfusions were given by restricted guidelines (transfusion threshold of 7 g/dL), although the patients were in stable clinical status and needed few transfusions. In contrast, unstable critically ill children may need more liberal RBC transfusions.

With chronic anemia, the decision to transfuse RBCs should not be based solely on blood hemoglobin levels, because children compensate well and may be asymptomatic despite low hemoglobin levels. Patients with iron deficiency anemia are often treated successfully with oral iron alone, even at hemoglobin levels < 5 g/dL. Factors other than hemoglobin concentration to be considered in the decision to transfuse RBCs include: (1) the patient’s symptoms, signs, and compensatory capacities; (2) the presence of cardiorespiratory, vascular, and central nervous system disease; (3) the cause and anticipated course of the anemia; and (4) alternative therapies, such as recombinant human erythropoietin (EPO) therapy, which is known to reduce the need for RBC transfusions and to improve the overall condition of children with chronic renal insufficiency (Chapter 529.2

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