b'2021 CARES Annual Report 5 5 IntroductionEMS-treated out-of-hospital cardiac arrest (OHCA) affects more than 250,000 Americans each year and is the third leading cause of disability adjusted life years (DALY) in the United States, behind cardiovascular disease and back pain. Typically, one in ten patients survives to hospital discharge, with 80% having no or moderate neurological disability. Cardiac arrest resuscitation is an important measure of a communitys emergency response readiness. Successful resuscitation requires involvement by a range of individuals including bystanders, emergency medical dispatchers, first responders, paramedics, and hospital providers. Performing bystander CPR can nearly double survival and public access defibrillation results in an almost 50% survival rate for patients presenting in a shockable rhythm. Its important to remember that these impactful community-based interventions happen in advance of 911 responders arriving on the scene. Without data on key indicators such as patient outcomes and bystander interventions, communities and EMS leadership lack information about how they are performing relative to others, as well as whether their quality improvement efforts are succeeding. Data collection is crucial in identifying gaps and planning next steps to strengthen the chain of survival. OHCA registries fill this role by compiling standardized measures at the community, state, and national level. Benefits of participating in such registries include determining patient outcomes, uniform benchmarking, identifying opportunities for improvement, and assessing the effectiveness of specific interventions1. The Cardiac Arrest Registry to Enhance Survival (CARES) allows communities to benchmark their performance with local, state, or national metrics to better identify opportunities to improve their OHCA care. CARES offers a comprehensive understanding of where arrests are occurring, whether bystanders are providing intervention prior to EMS arrival, EMS and hospital performance, and patient outcomes. This in turn provides the data necessary to make informed decisions and allocate limited resources for maximal community benefit. By creating an easy-to-use and flexible system to collect OHCA data and forming a community to share best practices, CARES has transformed the way EMS agencies are treating cardiac arrest. Participating agencies can make decisions in their community based on real-time feedback and analysis, in order to increase survival.The culmination of CARES occurs during the national reporting process, once the dataset for the calendar year is finalized. Participating states, EMS agencies, and hospitals receive their official CARES reports for the year. For 2021, over 9,500 reports were generated during the three-day reporting process, making it possible for every CARES participant to compare local, regional and national data for benchmarking and surveillance purposes with the goal of increasing survival from OHCA.We sincerely appreciate the members of the EMS and hospital CARES communities, as well as the sponsors (American Heart Association, American Red Cross, and Emory University Woodruff Health Sciences Center) who support our mission to save lives and improve patient care. We are pleased to present the 2021 Annual Report.1Graham R, McCoy MA, Schultz AM. Strategies to improve cardiac arrest survival: A Time to Act. Institute of Medicine. 2015.'