Outcome of Patients Requiring Medical ICU Admission Following Bone Marrow Transplantation: Methods
Over the past two decades, bone marrow transplantation (BMT) has become accepted as a standard treatment modality in adults with aplastic anemia (AA), acute lymphocytic leukemia (ALL), acute myeloid leukemia (AML), chronic myelogenous leukemia (CML), lymphoma, and certain solid tumors. Prior to BMT, patients receive conditioning regimens that include myeloablative chemotherapy often accompanied by total-body irradiation. For at least 2 weeks after BMT, patients will experience profound leuko-cytopenia and thrombocytopenia. This and the additional use of immunosuppressive therapy place these patients at increased risk for numerous complications, including opportunistic infections, bleeding, and graft-vs-host disease (GVHD).
Pulmonary complications have been observed in 40 to 60 percent of patients with BMTs. These include interstitial pneumonitis in up to 40 percent of allogeneic BMT recipients, bacterial, viral, and fungal pneumonias, cardiogenic and noncardiogenic pulmonary edema, bronchiolitis obliterans, and alveolar hemorrhage syndrome. With these severe acute complications, it has been estimated that 30 to 40 percent of BMT recipients require treatment.
The outcome of patients with BMTs with respiratory failure generally has been poor, with a 3 percent survival at 6 months in one series. Earlier work has focused specifically on these patients respiratory failure or on mixed medical and postoperative surgical patients admitted to critical care units. We report our experience with patients with BMTs with and without respiratory failure requiring mechanical ventilation admitted to a medical intensive care unit (MICU).
A registry of all patients admitted to the MICU between March 3, 1984 and March 26, 1991 was reviewed for patients who were status post-BMT. The medical records of 36 patients with a total of 43 admissions to the MICU were reviewed who underwent either allogeneic or autologous BMT. Variables that were studied included age, sex, underlying disease, remission status, type of transplant, conditioning regimen, and history of CVHD. The date and indication for admission to MICU were noted along with the need for mechanical ventilation, duration of mechanical ventilation, and overall length of stay. An APACHE II (acute physiology and chronic health evaluation) score was determined for the day of admission to the MICU. In the case of a patient with more than one admission to the MICU separated by at least 48 h, each was calculated as a separate admission. Statistical analysis was performed using Students t test, and the Mann-Whitnfcy rank-sum test. A p value of less than 0.05 was considered significant.