PROJECT SUMMARY: “Handoffs and Transitions in Critical Care – Understanding Scalability (HATRICC-US)” Modern care of the patient with acute cardiopulmonary failure requiring critical care support is marked by the inadequate adoption and use of interventions with proven effectiveness. There is an urgent need to characterize implementation strategies suitable for use in the fast-paced, high stakes environment of critical care; doing so would generate a substantial public health impact by narrowing the evidence-to-practice performance gap for these high-acuity patients. One such gap is caused by inconsistent adoption of standardized post-surgical handoffs in U.S. hospitals, an intervention deemed high priority by the American Heart Association. In this project, we use an evidence-based standardized protocol for patient care handoffs from the operating room (OR) to the intensive care unit (ICU) as a model to study the uptake and use of complex sociotechnical interventions in acute care. In previous work, our group demonstrated adoption, fidelity, and improvement in process outcomes in a pilot 2-site study of OR-to-ICU handoff standardization. Our published work in this area builds on a base of more than 65 published studies demonstrating the effectiveness of handoffs protocols on a range of outcomes relevant to the care of patients with cardiopulmonary failure, including process, provider, and patient outcomes. The proposed study is an extension of our work that will address critical knowledge gaps about implementation in acute care by studying the implementation of a standardized handoff protocol in 12 adult and pediatric ICUs in eight hospitals in five health systems. This pragmatic study is a Hybrid Type 2 effectiveness-implementation study with a dual focus on demonstrating improvements in short-term patient outcomes (composite measure of new-onset organ failure [co-primary]; adverse postoperative events) and implementation outcomes (fidelity [co- primary]; feasibility; acceptability; appropriateness; implementation cost; and sustainment over two years). The study integrates implementation frameworks, theories, and models with engineering approaches to workflow evaluation, intervention adaptation, and evaluation. Our specific aims are to: (1) elucidate handoff protocol implementation determinants using mixed-methods on-site contextual inquiry, (2) use an engineering approach known as participatory design to adapt the handoff protocol to each ICU and use theory-based implementation mapping to select tailored, multifaceted, multilevel implementation strategies, (3) implement handoff protocols in stepped wedge fashion with randomized roll-out under the leadership of site based teams, and (4) use human- centered design to create an implementation toolkit to facilitate the dissemination and use of study findings to a broad audience. The proximate goal of this work is to determine effective approaches to implementation for complex sociotechnical interv...