Historical outcomes of pediatric hematopoietic stem cell transplantation patients requiring critical care

Hematopoietic stem cell transplantation (HSCT) is being used to treat numerous malignant and non-malignant medical conditions in pediatric patients, but frequently is associated with severe medical complications. We review the outcomes of HSCT patients who developed complications requiring pediatric intensive care unit (PICU) care. The earliest reported patient cohorts, who were transplanted prior to 1990, had high PICU mortality rates, exceeding 80%. Patients transplanted from the 1980s-1990s varied more widely in mortality rates, with mortalities of 56-88% reported for mechanically ventilated patients and rates of 44-50% reported for studies including both mechanically ventilated and non-mechanically ventilated patients in PICU. The patient group transplanted from the 1990s to the early 2000s had reported mortalities of 46-60%. For patients transplanted after 2000, mortality rates were reported ranging from 37-69%. Two centers reported a significant improvement in mortality over time at their centers, although other institutions did not find similar changes. Factors associated with increased mortality included the need for mechanical ventilation, pulmonary pathology as a cause for intubation, severity of lung disease, multiorgan failure, and severe graft versus host disease. The Pediatric Risk of Mortality scoring system has not been consistently predictive of mortality; the modified Oncological Pediatric Risk of Mortality system was more predictive of mortality in several studies. Overall, the mortality of pediatric HSCT patients requiring PICU care has decreased, but remains substantial. Further study is needed to define clinical factors that affect outcome, so that treatments might be modified to improve survival.