BackgroundIn a previous study, we identified eight types of potential barriers to bystander cardiopulmonary resuscitation (CPR) initiation and continuation until the arrival of emergency medical services (EMS) on scene, in the context of emergency calls for out-of-hospital cardiac arrest (OHCA). Many cases had multiple barriers. In this study, we aimed to estimate the independent effects of these barriers after adjusting for case characteristics. MethodsWe used data for the 295 non-trauma OHCAs from the St John Western Australian (SJ-WA) OHCA Database. Excluded cases were: EMS-witnessed OHCA, callers not with/close to the patient, OHCA not recognised during the emergency call, bystander CPR in progress prior to the call and calls coded as obvious death by SJ-WA. We conducted two multivariable logistic regression models including the eight barriers (callers: 1) perceived inappropriateness of CPR, 2) emotional distress, 3) reluctance to perform CPR, 4) physical limitations, 5) access to the patient, 6) leaving the scene, 7) communication failure, and 8) on-scene distractions) and case characteristics. ResultsThe callers perceiving CPR as inappropriate (adjusted odds ratio [AOR] = 0.20, 0.11–0.37) and witnessed arrest (AOR = 2.88, 95% CI 1.48–5.60) were independently associated with CPR initiation. Caller distractions such as performing other tasks or relaying information to other bystanders were negatively significantly associated with callers continuing CPR to EMS arrival (AOR = 0.27, 0.10–0.73). ConclusionsPerceptions of inappropriateness and caller distractions were independent risk factors for the delivery of bystander CPR. Further research around how call-takers navigate these barriers and encourage callers should be performed.