Bystander CPR Best Hope for Out-of-Hospital Cardiac Arrest?

Patrice Wendling

July 17, 2017

COPENHAGEN — A new systematic review suggests that early defibrillation by lay bystanders may roughly double the number of survivors after an out-of-hospital cardiac arrest (OHCA) vs emergency first responders[1].

After examining data from 41 observational studies, Danish investigators found a median survival to hospital discharge of 53% when lay bystanders deliver defibrillation and 28.6% when delivered by professional first responders including police and firefighters.

The gap was similar in cases where the AED was attached but the defibrillation status was unknown (32% vs 11.5%, respectively).

"We believe this increased survival must be the timing, because the ambulance staff is so trained in using the AED they might get it on more quickly and do it in a more efficient way. But this just shows it's about getting it on and leaving the rest to the AED," lead author Dr Josefine Bækgaard (Emergency Medical Services, University of Copenhagen, Denmark) told | Medscape Cardiology.

The results, published July 7, 2017 in Circulation, also support the emerging strategy of using smartphone GPS technology to direct trained laypeople to an OHCA at the same time as EMS. Not only can these volunteers reach the OHCA patient more quickly, they can reach a larger population, including residential areas where 70% of OHCAs occur, the authors note.

"What we're pointing toward in this review is that this might be a very good solution," Bækgaard said.

Smartphone apps like Pulse Point and Good Samaritan are already in use in numerous US cities such as Seattle, a leader in OHCA response with a survival rate for OHCA due to ventricular fibrillation that hit 62% in 2013, or double the 2011 national average of 31%.

A recent blinded, randomized trial in Stockholm[2] reported that bystander-initiated CPR rates jumped from 48% in OHCA cases with no mobile alert to 62% when volunteers trained in CPR were alerted via mobile phone positioning of an OHCA within 500 m of them. Survival at 30 days was numerically better in the phone alert group (11.2% vs 8.6%).

A text-alert system in the Netherlands notifying volunteers of a suspected OHCA patient within 1000 m also increased defibrillation, particularly in residential areas, and shortened the average time to defibrillation by 2:39 min compared with EMS[3]. Copenhagen also recently launched a similar mobile text-alert system, Bækgaard said.

The present review included 41 studies from 11 countries, of which 18 reported lay-bystander AED usage, 20 EMS-dispatched professional first responders, and three both groups. It did not identify any EMS-dispatched volunteer responder studies using defibrillation eligible for inclusion.

Overall, the median survival to hospital discharge after OHCA treated with a public-access AED was 40% (range 9.1%–83.3%).

The 2015 American Heart Association and 2015 European Resuscitation Council guidelines recommend public-access defibrillation programs, and numerous states have made AED availability mandatory. Further, a collaboration between EMS leaders from around the world, known as the Global Resuscitation Alliance, has recently been formed with the aim to improve cardiac-arrest survival by, among others, increasing the use of public AEDs.

"The main problem is that these bystanders and laypersons generate such improved survival, but less than 5% of all out-of-hospital cardiac-arrest patients are defibrillated before EMS arrives," Bækgaard said. "It's one thing to place all these public AEDs, but we still need to engage the layperson to use them."

The research group at the Emergency Medical Services, Copenhagen received support from the Laerdal Foundation for Acute Medicine. The authors report no relevant financial relationships.

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