Effect of Smartphone Dispatch of Volunteer Responders on Automated External Defibrillators and Out-of-Hospital Cardiac Arrests

Abstract

ImportanceSmartphone dispatch of volunteer responders to nearby out-of-hospital cardiac arrests (OHCAs) has emerged in several emergency medical services, but no randomized clinical trials have evaluated the effect on bystander use of automated external defibrillators (AEDs).ObjectiveTo evaluate if bystander AED use could be increased by smartphone-aided dispatch of lay volunteer responders with instructions to collect nearby AEDs compared with instructions to go directly to patients with OHCAs to start cardiopulmonary resuscitation (CPR).Design, Setting, and ParticipantsThis randomized clinical trial assessed a system for smartphone dispatch of volunteer responders to individuals experiencing OHCAs that was triggered at emergency dispatch centers in response to suspected OHCAs and randomized 1:1. The study was conducted in 2 main Swedish regions: Stockholm and Västra Götaland between December 2018 and January 2020. At study start, there were 3123 AEDs in Stockholm and 3195 in Västra Götaland and 24 493 volunteer responders in Stockholm and 19 117 in Västra Götaland. All OHCAs in which the volunteer responder system was activated by dispatchers were included. Excluded were patients with no OHCAs, those with OHCAs not treated by the emergency medical services, and those with OHCAs witnessed by the emergency medical services.InterventionsVolunteer responders were alerted through the volunteer responder system smartphone application and received map-aided instructions to retrieve nearest available public AEDs on their way to the OHCAs. The control arm included volunteer responders who were instructed to go directly to the OHCAs to perform CPR.Main Outcomes and MeasuresOverall bystander AED attachment, including those attached by volunteer responders and lay volunteers who did not use the smartphone application.ResultsVolunteer responders were activated for 947 patients with OHCAs. Of those, 461 were randomized to the intervention group (median [IQR] age of patients, 73 [61-81] years; 295 male patients [65.3%]) and 486 were randomized to the control group (median [IQR] age of patients, 73 [63-82] years; 312 male patients [65.3%]). Primary outcome of AED attachment occurred in 61 patients (13.2%) in the intervention arm vs 46 patients (9.5%) in the control arm (difference, 3.8% [95% CI, −0.3% to 7.9%]; P = .08). The majority of AEDs were attached by lay volunteers who were not using the smartphone application (37 in intervention arm, 28 in control). There were no significant differences in secondary outcomes. Among the volunteer responders using the application, crossover was 11% and compliance to instructions was 31%. Volunteer responders attached 38% (41 of 107) of all AEDs and provided 45% (16 of 36) of all defibrillations and 43% (293 of 666) of all CPR.Conclusions and RelevanceIn this study, smartphone dispatch of volunteer responders to OHCAs to retrieve nearby AEDs vs instructions to directly perform CPR did not significantly increase volunteer AED use. High baseline AED attachement rate and crossover may explain why the difference was not significant.Trial RegistrationClinicalTrials.gov Identifier: NCT02992873

One-Year Review in Cardiac Arrest: The 2022 Randomized Controlled Trials

“…In particular, the community is highly encouraged to implement technologies, e.g., a smartphone app or text message, in order to improve the rate of bystander-initiated CPR and the use of automated external defibrillators (AED) [ 2 ]. In response to this encouragement, the “Swedish AED and Mobile Bystander Activation” (SAMBA) trial [ 9 ] investigated new strategies to improve early activation of emergency response for cardiac arrest. More specifically, the study evaluated whether a smartphone application for the dispatch of volunteer responders could increase the bystander use of AEDs in patients with OHCA before arrival of EMS or on-duty first responders (fire and police services).…”

“…Before this trial, only analyses on pre–post implementation of community apps for first-responder dispatch were available and anticipated reductions in the response time with volunteers arriving at the OHCA scene prior to EMS in the majority of instances [ 10 ]. Surprisingly, the SAMBA trial [ 9 ], the first RCT testing the real impact of smartphone alerting technologies to dispatch volunteer rescuers, failed to show any significant increase in volunteer AED use. However, it cannot be excluded that the neutral results of this study might have been confounded by the poor compliance to instructions and contamination of study groups by crossover [ 9 ].…”

“…Surprisingly, the SAMBA trial [ 9 ], the first RCT testing the real impact of smartphone alerting technologies to dispatch volunteer rescuers, failed to show any significant increase in volunteer AED use. However, it cannot be excluded that the neutral results of this study might have been confounded by the poor compliance to instructions and contamination of study groups by crossover [ 9 ]. Indeed, many volunteer rescuers retrieved and attached an AED even without receiving specific instructions.…”

Smartphone-activated volunteer responders and bystander defibrillation for out-of-hospital cardiac arrest in private homes and public locations

“…This is in alignment with a randomized trial from Sweden which did not find a significant increase in AED attachment when volunteer responders were activated. 33 …”

Improving Out-of-Hospital Cardiac Arrest Survival Rates—Optimization Given Constraints

“…The experience in countries such as Sweden, in which bystander CPR rates are over 50% and survival to discharge rates are over 20%, supports this assertion . The study by Berglund et al takes this logic a step forward in creatively leveraging a mobile telephone app that geolocates AEDs in Sweden using a national AED registry and linking these data with nearly 44 000 citizens trained in bystander CPR in 2 Swedish cities connected through a smartphone system (Heartrunner). This infrastructure served as the platform for a randomized clinical trial in which, in addition to dispatching EMS when notified of an OHCA, emergency dispatchers randomly provided volunteer responders with either alerts asking them to run to the OHCA to provide CPR (control group) or instructed 4 of the 5 closest identified trained bystanders to go get the nearest AED (route illustrated via geolocation software) with the closest individual instructed to go immediately to the OHCA to provide CPR (intervention group).…”