Findings from the ABC-PICU study may alter policies at hospitals where fresh red cells are preferentially used

A new study led by the Sainte-Justine University Hospital Centre and the University of Montreal, and Washington University School of Medicine in St. Louis has found that transfusions using fresh red blood cells—cells that have spent seven days or less in storage—are no more beneficial than older red blood cells in reducing the risk of organ failure or death in critically ill children. The results are published online today in the Journal of the American Medical Association.

Anemia is highly prevalent among children hospitalized in pediatric intensive care units. Red blood cell transfusion is the only way to rapidly treat severe anemia that could be life threatening. Red blood cells are stored in blood banks as red cell units for up to 42 days. Some findings published in the last few decades had suggested that transfusion with red blood cell units stored for longer time periods might be less beneficial than transfusion with fresher red cell units. The findings should reassure patients, families and doctors: the current standard blood bank practice, which involves dispensing older red cells, is just as safe and effective in these children, who are among the sickest and most fragile of patients. 

The study, one of the largest clinical trials to investigate red blood cell storage in critically ill children, sheds light on a controversial aspect of transfusion medicine that has been understudied. The study was funded by the Canadian Institutes of Health Research (CIHR) in Canada, by the National Heart, Lung, and Blood Institute (NHLBI) in the US, by the Programme Hospitalier de Recherche Clinique (PHRC) in France and by the Quebec Ministry of Health.

The study was led in collaboration by two principal investigators: Doctor Marisa Tucci from the Sainte-Justine University Hospital Centre and the University of Montreal in Canada and Doctor Philip Spinella from Washington University School of Medicine in St. Louis; both are pediatric intensivists and researchers. According to the investigators, the findings indicate that doctors who care for children in pediatric critical care units should not be afraid to use older red cells in their patients. The results from this study suggest that those who systematically request fresh red cells should consider discontinuing this practice unless there are extenuating circumstances. The study findings provide good news for blood banks, who will likely feel less pressure to respond to requests for fresh red cells.

Red blood cell transfusions are commonly administered in critically ill children with illnesses that increase the need for transfusion such as trauma, cancer chemotherapy, major surgery with significant intraoperative bleeding, and for conditions such as sickle cell disease and thalassemia. Transfusing the oldest red cells in the stored inventory first is standard practice among many hospitals to avoid wastage. However, some hospitals preferentially give fresh red blood cells for some critically ill children, even though clinical studies supporting the benefits of this practice have been lacking.

To help fill the research gap, the investigators of the Age of Blood in Children in Pediatric Intensive Care Units (ABC-PICU) study undertook a randomized trial that recruited patients admitted to pediatric intensive care units in 50 medical centers. The study began in February 2014 and ended in November 2018; 1,461 children aged 3 days to 16 years admitted to pediatric intensive care units were recruited in the United States (29 sites), Canada (10 sites), France (8 sites), Italy (2 sites), and Israel (1 site); Sainte-Justine University Hospital was the coordinating center in Canada and recruited the greatest number of patients (over 160). Data management and analysis was done by Dr Dean Fergusson from the Centre for Practice-Changing Research at the University of Ottawa de l’Université d’Ottawa along with Drs Tucci and Spinella. During the course of the study, half of the patients received transfusions with fresh red blood cells stored for seven days or less and half received transfusions with older red cells. The primary outcome measured was the development of new or progressive multiple organ dysfunction (impairment of one or more organs). The researchers found that fresh red cells did not reduce the incidence of new or progressive multiple organ dysfunction or death compared to older red cells and that the outcomes were not significantly different between the two groups. About 20.2% of those who received fresh red cells experienced new or progressive organ dysfunction while 18.2% of those who received older red cells experienced similar dysfunction.

The relatively large number of patients recruited and geographic diversity as well as the inclusion of a wide variety of patients were among its strengths, making it reasonable for researchers to generalize the findings to a larger pediatric population. The researchers did note some caveats. The study did not examine whether the use of the oldest red cells allowable (more than 35 days) affects outcomes, or if fresh red cells affect outcomes for children requiring large-volume red cell transfusions. The children in this study received low-volume red cell transfusions.

The results of this study are applicable to the vast majority of children in pediatric intensive care units and show that current red blood cell transfusion practices are safe.