Pediatric Bone Marrow Transplantation: Intensive Care Management

Abstract

Bone marrow transplantation (BMT) has assumed increasing importance in the treatment of bone marrow failure, hematopoietic malignancies, congenital immunodeficiencies, and solid tumors. Children undergoing BMT are at high risk for infection and hemorrhage during the period of aplasia. In addition, life-threatening complications of circulatory, pulmonary, gastrointestinal, hepatic, and renal function are common and frequently require intensive supportive care. This review provides an overview of pediatric BMT that focuses on management problems relevant to intensive care. Thorough pretransplantation assessment of underlying organ dysfunction is mandatory before undertaking BMT. The complications associated with preconditioning regimens that use total body irradiation and high doses of ablative chemotherapy are described. Finally, problems involving individual organs are discussed by systems. The challenge of improving the results of BMT in the treatment of childhood malignant and hematopoietic disorders depends, in large part, on successful preventive measures and good management of complications that occur immediately before and within the first 100 days after transplantation. As BMT is indicated for treatment of an increasing number of diseases, more patients will require the care of intensivists familiar with transplantation-related complications. General ConsiderationsBone marrow transplantation (BMT) has assumed increasing importance in the treatment of aplastic anemia [ 1 ], congenital immunodeficiency diseases [2], the leukemias [3-6], and a variety of other malignancies [7]. Because many of these disorders occur during the first two decades of life, children are frequently referred for BMT. Clinical experience has shown that children undergoing BMT tolerate intensive chemoradiotherapy better and have a markedly lower incidence of notable graft-versushost (GVH) disease than their adult counterparts [8,9]. Our purpose in this review is to focus specifically on problems the intensivist is likely to confront in managing children during BMT. BMT is, in itself, a simple procedure. The donor is anesthetized and marrow is harvested by multiple aspirations from the iliac crest. The marrow is filtered mechanically and infused in the form of a blood transfusion. Donor cells migrate to the recipient's bone marrow and active hematopoiesis usually resumes within a few weeks after BMT. Major problems encountered in BMT include the toxicity of intensive conditioning regimens designed to eradicate host immunologic function or residual malignant cells, a prolonged period of pancytopenia and severe immunodeficiency when opportunistic infections are frequently life threatening, and GVH disease in which immunocompetent donor cells attack a variety of host organs. Despite these formidable hurdles, BMT cures 70 to 80% of patients with severe aplastic anemia [10], and excellent results have been observed in the treatment of leukemia and other disorders [2][3][4][5][6][7].