Leveraging implementation and behavioral science to reduce harmful overuse of diagnostic testing in critically ill children - Project Abstract Overtreatment – health care in which the benefit does not outweigh risks – accounts for up to $200 billion annually in the United States, and is associated with worse outcomes and death. Unnecessary use of diagnostic testing is a primary driver of overtreatment. Diagnosing and treating suspected sepsis exemplifies this challenge. In hospitalized children, severe sepsis is common (8.2% prevalence) and deadly (25% mortality rate). Pediatric hospitals prioritize early sepsis recognition and rapid antibiotic administration as key performance metrics. Signs and symptoms of sepsis in children, however, are non-specific. The resulting diagnostic uncertainty may lead to harmful overtreatment. Blood cultures are the gold standard for diagnosing sepsis due to bacteremia. Frequently, clinicians obtain blood cultures and simultaneously start empiric broad-spectrum antibiotics. Only 5-15% of cultures will be positive, however, and up to 50% of those are actually falsely positive. False positive results lead to unnecessary antibiotics, increased lengths of stay, and increased costs. Reduction in unnecessary blood cultures in pediatric intensive care unit patients is feasible and safe, but current practice patterns for blood culture use vary widely, and culture use may be driven by reflexive behavior and fear of missing sepsis. With my Primary Mentor, I have been leading an AHRQ-funded 14-site PICU blood culture quality improvement collaborative called Bright STAR (R18 HS025642-01) since 2017. I will now leverage Bright STAR to 1) investigate what leads to blood culture overuse in the PICU, and 2) develop and test strategies to safely reduce blood culture overuse. I will use the Consolidated Framework for Implementation Research, the concept of cognitive bias, and the Proctor implementation framework to accomplish these objectives, in a series of qualitative, quantitative, and quasi-experimental research investigations. This proposal will give me experience in: applying frameworks of implementation/behavioral science, conducting mixed methods studies, designing implementation strategies, and conducting a clinical trial. These skills are critical to achieving my long term goal: to design and test strategies to safely reduce harmful overuse of other unnecessary diagnostic tests (and consequently, unnecessary treatments) in critically ill children. I will be mentored by a team of highly funded, successful researchers with expertise in infectious diseases, implementation science, behavioral science, trial design, and mixed methods research. I will have the full support of the Division of Critical Care at The Children's Hospital of Philadelphia and the University of Pennsylvania, with access to innumerable resources (such as the Penn Implementation Science Center, the Center for Pediatric Clinical Effectiveness research, and the Penn Mixed-Methods Laboratory) to help me accomplish my aims. I will use this award to become an independent implementation scientist improving patient outcomes by reducing harmful overuse of unnecessary tests in critically ill children on a large scale.