First “First Responder” Study

R&D Ref. 2015/0342
REC Ref. 15/SS/0128

Research to date is very clear that quick action is essential to improving the probability of survival and good brain function following OHCA. Even brief delays in calling for help or beginning CPR can have a profound impact on whether resuscitation is successful or not. For every minute that a defibrillatory shock is delayed after the onset of a shockable cardiac rhythm, the survival rate decreases by 7-10% (Holmberg et al. 2000, Larsen et al. 1993). Performing CPR during this interval slows the rate of survival decline to just 3-4% per minute, allowing emergency services to get to the scene while the patient is still salvageable (Laren et al. 1993; Valenzuela et al. 1997). Empirical evidence from multiple studies suggests that bystander CPR increases the OHCA victim’s chance of survival by between 2 and 3 times (Lloyd-Jones, et al., 2009) and bystander CPR is cited as a major factor in the success of centres with the world’s best OHCA survival rates (Kellermann 2010).

Despite the bystander responder’s critical role in summoning and delivering help to the victim, almost no information exists as to how the bystander makes crucial decisions, such as when to call emergency services, or whether to begin CPR. Similarly, the impact of such an experience on the subsequent well-being of the bystander, and what support may be helpful or necessary for them, has not been evaluated.

This study aims to provide the first in-depth look into the experience of the OHCA bystander responder. These insights will allow us to look for ways we can improve the early steps in the “chain of survival” following OHCA — the steps often most likely to bring about the biggest improvements in patient survival and function after a cardiac arrest. Information about how we could deliver care to OHCA victims better and faster, before professional help has arrived, can be used to inform public education efforts, aspects of public policy, and emergency medical systems design. Further, this research investigates the emotional impact of participating in OHCA for the bystander who responds, directing much delayed attention to their emotional responses and well-being.

Research goals: To provide the first in-depth understanding of the non-medical person’s experience responding to an OHCA, allowing exploration of two main objectives: 1) identifying ways in which initial prehospital care of the OHCA patient might be improved, and 2) identifying the risks and benefits of involvement in OHCA response for non-medical persons, and how that experience might be made easier for those respond.


For more information please contact the study team on 0131 242 9352.

Status: closed

Start Date

February 2016

Coordinated by

EMERGE-RRG team on behalf of University of Edinburgh (

Main Trial Site


End date

May 2017