Project Summary Each year, an estimated 530,000 adults die of cardiac arrest in the USA. Mortality rates are excessively high – 90% for out-of-hospital events and 75% for in-hospital events – and have remained unchanged for over a decade. Early high-quality cardiopulmonary resuscitation (CPR) is the most critical lifesaving intervention for a patient in cardiac arrest. There is a need for highly functioning point-of-care tools to 1) assist practitioners during a cardiac arrest response, 2) allow for regular training in in-situ settings, and 3) enable data-rich performance-focused peer debriefing. In our predicate SBIR Phase I proposal, XiMiO Health, Inc. proposed developing the first smartwatch-enabled Basic Life Support (BLS) application for use in both training and clinical response - a system we call Relay Response. Our first specific aim was to design a BLS App with real-time decision support to American Heart Association (AHA) protocols and real-time CPR depth and rate performance feedback. To accomplish this, we proposed developing an app with an intuitive user interface capable of displaying real-time depth and rate feedback from a novel algorithm that calculates depth and rate from accelerometer sensor data. Additionally, we proposed developing a cloud-based database linked to our BLS App to enable real-time data sharing between rescuers responding to a cardiac arrest. Shortly, we will begin benchtop testing to demonstrate proof-of-concept that our BLS App performs as intended. Our second specific aim was to test the feasibility of our BLS App in a CPR simulation study. The study will include 30 participants with a wide range of CPR experience (in-hospital providers, EMTs, and noncertified personnel), using CPR manikins to establish proof-of- concept validation of the BLS App’s performance and utility as a CPR aid. Our study is on schedule and will commence in Q1 2022. With the I-Corps program, the Team’s objective is to validate and characterize our beachhead market for the BLS App – inclusive of developing buying personas, value propositions, pricing models, and sales processes. We expect our success in characterizing our beachhead market during the I-Corps program will allow us to establish early commercial customers and sales channel partnerships. Additionally, the commercial traction that will result from us successfully completing the I-Corps program will reduce the commercial risk to institutional investors and will accelerate our ability to attract venture capital. Ultimately, we believe our success will provide strong support to our SBIR Phase II application, which we anticipate submitting in Q2 2022.