International Study of the Epidemiology of Platelet Transfusions in Critically Ill Children with an Underlying Oncologic Diagnosis

Objectives: To describe the epidemiology of platelet transfusions in critically ill children with an underlying oncologic diagnosis and to examine effects of prophylactic versus therapeutic transfusions. Design: Subgroup analysis of a prospective, observational study. Setting: Eighty-two PICUs in 16 countries. Patients: All children (3 d to 16 yr old) who received a platelet transfusion during one of the six predefined screening weeks and had received chemotherapy in the previous 6 months or had undergone hematopoietic stem cell transplantation in the last year. Interventions: None. Measurements and Main Results: Of the 548 patients enrolled in the parent study, 237 (43%) had an underlying oncologic diagnosis. In this population, 71% (168/237) of transfusions were given prophylactically, and 59% (139/237) of transfusions were given at a total platelet count greater than 20 × 10⁹/L, higher than the current recommendations. Those with an underlying oncologic diagnosis were significantly older, and received less support including less mechanical ventilation, fewer medications that affect platelet function, and less use of extracorporeal life support than those without an underlying oncologic diagnosis. In this subpopulation, there were no statistically significant differences in median (interquartile range) platelet transfusion thresholds when comparing bleeding or nonbleeding patients (50 × 10⁹/L [10-50 × 10⁹/L] and 30 × 10⁹/L [10-50 × 10⁹/L], respectively [p = 0.166]). The median (interquartile range) interval transfusion increment in children with an underlying oncologic diagnosis was 17 × 10⁹/L (6-52 × 10⁹/L). The presence of an underlying oncologic diagnosis was associated with a poor platelet increment response to platelet transfusion in this cohort (adjusted odds ratio, 0.46; 95% CI, 0.22-0.95; p = 0.035). Conclusions: Children with an underlying oncologic diagnosis receive nearly half of platelet transfusions prescribed by pediatric intensivists. Over half of these transfusions are prescribed at total platelet count greater than current recommendations. Studies must be done to clarify appropriate indications for platelet transfusions in this vulnerable population.