Public Access Defibrillation (PAD) Community Trial

BACKGROUND:

Sudden out-of-hospital cardiac arrest (OOH-CA) remains a significant cause of death, in spite of recent declines in overall mortality from cardiovascular disease. Existing methods of emergency resuscitation are inadequate due to time delays inherent in the transport of a trained responder with defibrillation capabilities to the side of the OOH-CA victim.

Existing Emergency Medical Services (EMS) systems typically combine paramedic Emergency Medical Technician (EMT) services with some level of community involvement, such as bystander cardiopulmonary resuscitation (CPR) training. Some communities include automated external defibrillators (AEDs) at isolated sites or in mobile police or fire vehicles. Such an approach typically varies in effectiveness, with an incremental improvement in effectiveness seen in communities that organize and integrate services with the existing EMS system. However, optimal improvement in survival from sudden OOH-CA may require a program that utilizes volunteer non-medical responders (who may not have a traditional duty to respond to an emergency) who are successfully trained to use AEDs. A comprehensive, integrated community approach to treatment with AEDs would have community units served by these volunteer non-medical responders who can quickly identify and treat a patient with OOH-CA. Such an approach is termed Public Access Defibrillation (PAD).

Some observational studies suggest support for the PAD approach. These studies have targeted traditional public safety responders such as police and firefighters or other laypersons in leadership positions who are trained and regularly called upon to take command in an emergency (e.g., airline flight attendants, security officers in Las Vegas casinos). Other studies, both randomized and observational, where trainees have been spouses or family members of at-risk patients, suggest that not all laypersons can effectively utilize AEDs in the setting of OOH-CA, even with extensive training. This study differs from those conducted previously by focusing on an intermediate group, namely, volunteer non-medical responders (e.g., merchants, bank tellers, building superintendents, and co-workers). This study will provide results that may help to develop informed public policy regarding the use of AEDs by volunteer non-medical persons.

DESIGN NARRATIVE:

This was a study of a comprehensive, integrated community approach in which volunteer non-medical responders (lay volunteers without a traditional responsibility to take charge in medical emergencies as their primary job description) were trained to use automated external defibrillators (AEDs). This approach is called Public Access Defibrillation (PAD). The hypothesis investigated was that PAD would significantly increase survival in out-of-hospital cardiac arrest by reducing the time interval from collapse to defibrillation. The specific aim of this randomized, controlled trial was to measure survival to hospital discharge following out-of-hospital cardiac arrest in community units trained and equipped to provide public access defibrillation in addition to optimal standard care, compared to community units trained to provide optimal standard care (recognition of out-of-hospital cardiac arrest, 911 access, cardiopulmonary resuscitation). Secondary aims included the comparison using Utstein criteria (Annals of Emergency Medicine 1991;20:861-74), neurological status, quality of life, cost, and cost-effectiveness between the two groups.

Participating research sites identified 1,000 units (e.g., public areas, gated communities, shopping malls, airport terminals, casinos, business parks) within their service area that anticipated at least 0.6 treatable out-of-hospital cardiac arrests within a 15 month period. Each unit was randomized to serve as either an intervention or control group, with comparative episode data collected for a 15 month period following a short preliminary data collection period (approximately 2 months to evaluate the ability for the site to capture event data) after training. Within each site, units were sub-randomized to a retraining strategy. Performance at retraining was monitored, and strategies modified if indicated.

Volunteer non-medical responders (e.g., office staff, bank tellers, merchants, and neighborhood volunteers) in both the intervention and control groups will be trained to provide the optimal standard of care: (a) recognize out-of-hospital cardiac arrest; (b) access 911 or its equivalent; and, (c) administer CPR. Volunteers in the intervention group will also be taught to use an AED promptly while awaiting arrival of the first public safety emergency medical team. The criteria for number and location of trained volunteers and devices will be a maximum 3-minute "walk through" to have the AED at the patient's side.

Out-of-hospital cardiac arrest victims in each of the two groups will be compared over the 15 month intervention period with respect to their: (a) survival to hospital discharge (primary outcome); (b) neurological status; (c) quality of life; and, (d) resource use/costs. The incremental cost-effectiveness of volunteer non-medical responder defibrillation will be calculated.