Red Blood Cell Transfusion Safety: Probabilistic Risk Assessment and Cost/ Benefits of Risk Reduction Strategies

While transfusion safety, particularly with respect to transfusion-transmitted infectious diseases, has improved dramatically over the past several decades, progress in other clinical processes of blood product transfusion continue with highly variable practices and human errors that contribute to adverse outcomes. In this paper, we study the adverse outcome risk in red blood cell (RBC) transfusion in the United States using Probabilistic Risk Assessment (PRA). PRA allows us to map, in a comprehensive manner, the various types of events that may contribute to an adverse outcome, including socio-technical factors such as the risk coming from human error; and allows us to formalize the logical relationships among those events and the adverse outcome risk. We utilize the PRA model to assess the risk to the patient from RBC transfusion in the United States, to identify the major risk points in the transfusion process, and to evaluate the costs and benefits of several risk reduction strategies. Our data come from published studies in the medical literature. We find that the risk of a potentially severe outcome (e.g., mortality, major injury or other serious long-term consequences, a life threatening incident) from RBC transfusion lies in the interval [10.4327,511.2] per 100,000 units of RBC transfused, with a point estimate of 25.4527. The leading causes of severe outcomes include circulatory overload and bacterial infection. Acute hemolytic reactions, which are mainly caused by erroneous administration of the blood, also contribute significantly to severe outcomes of transfusion. Interestingly, our analysis indicates that an intervention that is targeted at reducing the risk of the erroneous administration of blood (through training programs or technology investments) has a higher potential impact in reducing the severe outcome risk from RBC transfusion than additional screening to further reduce the risk of transfusion-transmitted viral infections, of HIV 1-2, hepatitis B, and hepatitis C, which the lay public fears most. Furthermore, such an error reduction program will be more cost-effective than the additional screening of donated blood. Our study provides guidelines for public policy to improve the safety of RBC transfusion in the United States.