Project Summary-Abstract The extended response to the novel coronavirus 2019 (COVID-19) pandemic has increased clinician work burden and risk for infection while creating an environment of uncertainty, especially as easing of government lockdown measures and potential additional surges of infection are expected in the near future. System responsiveness and clinician preparedness are needed to prevent safety threats for both patients and staff. Rapidly evolving care guidelines for COVID-19 patients result in continuous changes to implementation at the bedside, presenting the opportunity for unintended consequences and the introduction of latent safety threats. Clinician exposure to acute occupational stress events can lead to an activation of the sympathetic nervous system, resulting in key physiologic changes including a decrease in heart rate variability. Repeated or continuous stress exposure, leading to lower heart rate variability, is linked to increased medical errors and decreased patient satisfaction. Simulation, a technical field that applies experiential techniques to practice, learn, evaluate, test, systems or human actions, provides a proven methodology for improving system responsiveness and process improvement. We recently developed and piloted a new rapidly adaptive simulation intervention to increase guideline adoption and preparedness for COVID-19 care delivery. Building upon this work, our overall goal is to develop and test the COVID-19 Responsive Intervention: Systems Improvement Simulations (CRI:SIS), a simulation- based training and quality improvement intervention that will minimize physician stress and improve system responsiveness. To accomplish this goal, we will first identify facilitators, barriers, and unintended safety risks in the adoption of new COVID-19 guidelines through in-depth interviews with emergency physicians and structured field observations during the care of critically ill COVID-19 patients. Next, we will conduct a two-site randomized clinical trial to test the efficacy of CRI:SIS as a simulation-based preparedness intervention on decreasing emergency physician stress and anxiety during the care of COVID-19 patients in the ED through on-shift measurements of heart rate variability as a physiologic marker of stress and responses to the State- Trait Anxiety Inventory post-shift. Finally, we will test CRI:SIS as a process improvement strategy through rapid cycle iterative loops of simulation-based testing of guidelines and design prototyping with our departmental administrators, measuring changes to the AHRQ Hospital Survey on Patient Safety Culture. We will rapidly disseminate CRI:SIS as two simulation interventions, one on clinician preparedness and the other on system improvement, through interactive virtual tele-simulations, webinars, and virtual workshops providing mentorship and shared learning for other institutions facing similar challenges. If proven successful, our simulation-based CRI:SIS interve...