Fatal opioid overdose remains a public health epidemic in the United States. Each day, 115 Americans die from opioid overdose, and data from the Centers for Disease Control and Prevention (CDC) indicate the epidemic is worsening. Unlike many life-threatening medical emergencies, opioid toxicity is readily reversed with rapid identification and administration of the overdose antidote naloxone or supportive respiratory care. Thus, a fundamental challenge of fatal opioid overdose events is that victims die alone or among untrained or impaired bystanders, with insufficient timely diagnosis and treatment.

We present Second Chance a smartphone based system that can detect opioid overdose precursors and connect potential overdose victims with widely available life-saving interventions. Our software system, which runs as an application on smartphones, converts the phone into a short-range active sonar system, using frequency shifts to identify respiratory depression, apnea, and gross motor movements associated with acute opioid toxicity. By creating overdose detection algorithms that can be used on devices most high-risk individuals already own, we hope to provide a harm reduction system that can automatically connect with naloxone-equipped friends and family or Emergency Medical Services (EMS) to help prevent fatal overdose events.