Background: During the last few years, considerable focus has been given to the management of anemia and coagulopathies. This article provides current concepts of red blood cell (RBC) and plasma coagulation factor replacements.
Methods: The literature was reviewed for clinical studies relevant to RBC transfusion indications and outcomes as well as for the uses of coagulation factor replacement products for coagulopathies most likely encountered in patients with cancer.
Results: Most patients without complications can be treated with a hemoglobin level of 7 g/dL as an indication for RBC transfusion. However, the effects of disease among patients with cancer may cause fatigue, so transfusions at higher hemoglobin levels may be clinically helpful. Leukoreduced RBCs are recommended as standard therapy for all patients with cancer, most of whom do not develop coagulopathy. Transfusions to correct mild abnormalities are not indicated in this patient population. Data are inconclusive regarding the value of coagulation factor replacement for invasive procedures when the international normalized ratio is below 2.
Conclusions: Indications for RBC transfusion have become more conservative as data and experience have shown that patients can be safely and effectively maintained at lower hemoglobin levels. Coagulation factor replacement is unnecessary for most modest coagulopathies.
Transfusion is an important part of cancer therapy. Red blood cells (RBCs) may be needed because of myelosuppression for chemotherapy or anemia in the setting of chronic disease. Because of myelosuppression, platelets are often part of the continuum of care for patients with cancer. Typically, plasma is not needed because coagulopathy is not a major aspect of cancer or its therapy. However, in infrequent situations in which coagulation factor replacement is needed, plasma can be vital to the treatment of patients with cancer. Most infections can be managed with antimicrobials; however, granulocyte transfusions may sometimes be considered for recalcitrant infections in patients with neutropenia. The uses and indications for all of these blood components have undergone changes over the last few years. This report is a summary of those changes and the current clinical indications and uses of RBCs, plasma, and granulocytes.
RBC transfusion is common in the treatment of patients with cancer.1-4 Overall, patients with oncological and hematological malignancies use around 34% of the RBC supply.1 In patients with cancer, as is similar with any other patient population, the indication for RBC transfusion is to alleviate symptomatic anemia. The decision to transfuse should not be driven by the hemoglobin concentration, and no single criterion can be used as an indication for RBC transfusion. Thus, the patient’s clinical status should be of utmost consideration.5
Anemia may occur in 90% of patients during chemotherapy and, furthermore, cancer treatments often cause the loss, destruction, and decreased production of RBCs — all of which lead to anemia.6 In particular, lung and gynecological cancers are associated with anemia because the treatments for such cancers include platinum-based therapies.7 Anemia in cancer may decrease quality of life and increase cancer-induced fatigue. Cancer-associated anemia may also be an indicator of poor clinical outcomes.8 If urgent correction of anemia is unnecessary, then erythropoietin treatment may be a valid alternative to RBC transfusion and can decrease RBC transfusion rates.9
In general, RBC transfusions are used to treat (1) tissue hypoxia due to inadequate RBC mass, (2) acute anemia due to trauma or surgical blood loss, (3) anemia in patients receiving chemotherapy, and (4) cardiovascular decompensation of chronic anemia. They are also used to ensure the optimal tissue oxygenation in patients with anemia undergoing radiation therapy. RBC transfusion is not indicated for the correction of anemia due to iron deficiency, as a source of nutritional supplementation, or in volume expansion.
Dynamic physiological changes in patients with anemia help allow the decreased RBC mass to continue to oxygenate tissue. In brief, these changes include increased blood flow (as blood viscosity decreases) and increased oxygen offloading in hypoxic tissues (as the concentration of 2,3-diphosphoglycerate increases in the RBCs). In the setting of anemia, the overall blood volume is maintained with increased plasma volume. Compensatory cardiac output changes maintain adequate perfusion. As a result of these dynamic physiological changes, symptoms of anemia rarely manifest until hemoglobin values significantly dip. Animal studies indicate that extreme hemodilution can be tolerated in healthy animals.10 One study showed that 6 of 7 baboons survived hematocrit levels down to 4% and that they maintained adequate cardiac compensation at hematocrit levels as low as 10%.11 In addition, humans can tolerate very low levels of hemoglobin.12,13
RBC transfusions have been used for decades; recently, the effectiveness of RBC transfusions has been evaluated in randomized trials so that the best evidence can be ascertained to guide transfusion decisions. In some patient populations, nontransfused patients have better outcomes than transfused patients and patients who receive fewer units do better than those who receive more RBC units.14-16 The following clinical trials described below illustrate this concept.