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Abstract

Out of Hospital Cardiac Arrest (OHCA) is the most time sensitive medical emergency that occurs in the community. Approximately 60,000 Canadians per year will experience OHCA, with an overall survival of 2-5%. In most jurisdictions, 75% of these cases occur with no bystander present to alert authorities and provide lifesaving interventions. Many of these unwitnessed cases experience prolonged intervals prior to discovery and have poor survival (0-1%). In the past decade, advancements in wearable technology have led to discussions about how wearable devices may act as a virtual bystander and reduce the proportion of cases that are not detected at the time of onset. I conducted several studies to better understand the potential impact of these technologies and support their development and validation. I constructed a causal framework linking the effect of a bystander to the hypothetical effect of technology-aided recognition and estimated the impact of increasing the proportion of cases that were detected at the time of onset with these technologies. Using data from a clinical registry, I found that survival would have doubled if all previously unwitnessed cases had been detected by a wearable device at the time of onset. I extended this approach to estimate which types of cases may benefit the most and found that detecting cases that occurred at home would translate to the most clinical benefit. Having determined the potential benefits from these technologies, I reviewed the research and commercial literature to understand current and future options for technology aided detection of OHCA. This identified limited real-world testing but established that existing sensors such as photoplethysmograms (PPGs) and accelerometers were best suited using a multimodal approach. However, an obstacle in developing these technologies is a lack of suitable human testing settings, given the rarity of OHCA. Based on this, I developed a clinical study to collect cardiac arrest and non-cardiac arrest data from individuals receiving palliative care and medical assistance in dying. I implemented this protocol to determine the feasibility of testing wearable technology in human participants. Finally, I evaluated the design considerations for real-world trials of these technologies in a community setting.