Smartphone Activated Volunteer Responders Arriving prior to Emergency Medical Services is Associated with Increased Survival to Discharge following Out of Hospital Cardiac Arrest

Miss Belinda Delardes¹, Dr. Mads Christian Tofte Gregers², Ms. Emily Nehme^1,3, Mr. Michael Ray¹, Mr. Dylan Hall¹, Prof Tony Walker³, Dr. David Anderson^1,3, Dr. Daniel Okyere^1,3, Ms. Ashanti Dantanarayana¹, Dr. Ziad Nehme^1,3

¹Ambulance Victoria, Blackburn North, Australia, ²Copenhagen University Hospital, Denmark, ³Monash University, Melbourne, Australia

Biography:

Belinda is an ALS paramedic from metropolitan Melbourne with a strong interest in research and is a current PhD candidate. She has been a Resuscitation Coordinator with Ambulance Victoria for the past three years and is a member of the Global Resuscitation Alliance, developing a passion for improving OHCA management.

Abstract:

Introduction: We conducted an observational study investigating Out of Hospital Cardiac Arrests (OHCAs) which were eligible for Smartphone Activated Volunteer Responder (SAVR) dispatch. We aimed to determine if OHCAs with at least one SAVR arriving prior to emergency medical services (EMS) would have increased rates of survival to discharge compared with OHCAs where EMS arrived first.

Methods: Population‐based observational cohort study of consecutive non-EMS witnessed OHCAs that were eligible for SAVR activation in Victoria, Australia, from February 12, 2018, to May 31, 2023. We included adult patients ≥18 years of age. Cases were excluded if they occurred in a residential aged care facility, did not receive EMS resuscitation, the dispatch code was ineligible for SAVR activation or occurred during the COVID-19 pandemic lock-down periods due to the pausing of the SAVR program.

Results: A total of 9,196 cases were included, of which 1,158 (12.6%) had a SAVR arrive on scene, with arrival prior to EMS in 564 (48.7%) cases. After risk-adjustment, a SAVR arriving before EMS resulted in a near eight-fold increased odds of bystander CPR (adjusted odds ratio [AOR] 7.62, 95%CI 4.99 – 11.64), sixteen-fold increased odds of bystander defibrillation (AOR 15.63, 95%CI 9.08 – 26.9), and 38% increased odds of survival to hospital discharge (AOR 1.38, 95%CI 1.03 – 1.85). Conversely, a SAVR arriving after EMS was not associated with bystander CPR, bystander defibrillation, or patient outcomes.

Conclusion: SAVR arrival prior to EMS was associated with increased rates of bystander CPR, defibrillation, and patient survival to hospital discharge.