1156: THE BYSTANDER EFFECT: THE INFLUENCE OF KNOWN BYSTANDER CPR AND WITNESSED ARREST ON ED CPR DURATION

Abstract

Introduction: Long term outcomes for patients with out-of-hospital cardiac arrest (OHCA) are generally poor, with global 1-month survival rates of just over 10%. Witnessed cardiac arrest and bystander cardiopulmonary resuscitation (CPR) are associated with improved rates of ROSC and survival to hospital discharge. The goal of this study is to evaluate the relationship between known bystander CPR and witnessed cardiac arrest on physician decision to terminate resuscitation in the ED. Methods: We prospectively evaluated a consecutive sample of OHCAs that presented to a single tertiary care emergency department from 2018-2019. Data were collected via video surveillance of ED resuscitation bays in combination with patient chart review. Multivariate linear regression was used to evaluate the relationship between witnessed cardiac arrest, bystander CPR, and time to termination of resuscitation. Results: A total of 71 patients met inclusion criteria of OHCA with EMS CPR and termination of resuscitation in the ED. 51 patients had a non-shockable initial presenting rhythm and 20 patients presented with shockable rhythms. Bystander CPR was associated with an average decrease in ED CPR duration of 7.4 minutes (p = 0.02) for patients with non-shockable rhythms, but was not associated with ED CPR duration for patients with shockable rhythms (y = 0.49; p = 0.95). There was no difference in time to termination between witnessed and unwitnessed cardiac arrests. Conclusions: The performance of bystander CPR is one of the most important links in the chain of survival that improves clinical outcomes in cardiac arrest. In our population, bystander CPR was a significant factor in physician decision to terminate resuscitation for patients presenting in non-shockable rhythms. Patients with shockable rhythms were resuscitated longer and without consideration of bystander CPR or presence of witnessed arrest, which may be related to known better chances of ROSC and overall neurologic outcomes for these patients. These findings suggest that bystander CPR may be factored into the total resuscitation time by emergency clinicians when considering the multifactorial decision to terminate CPR.