Abstract
OBJECTIVES: To evaluate the agreement between bystander cardiopulmonary resuscitation (B-CPR) documented by emergency medical services (EMS) personnel in the Birmingham Cardiac Arrest Registry to Enhance Survival (CARES) and B-CPR identified through 9-1-1 audio review. METHODS: We conducted a retrospective observational analysis of adult non-traumatic out-of-hospital cardiac arrest (OHCA) cases in Birmingham from January 1 to December 31, 2023. We excluded EMS-witnessed events, those in nursing homes, health care facilities, jails/prisons, or involving patients who were conscious during the 9-1-1 call. The provision of B-CPR was classified as "yes" or "no" in CARES based on EMS documentation and compared to B-CPR status determined through review of the corresponding 9-1-1 audio by a single reviewer. Agreement between sources was assessed using percent agreement, Cohen's kappa, Gwet's AC, and McNemar's test. RESULTS: Of 236 total cases, EMS documented a B-CPR rate of 12.3% whereas audio review indicated a B-CPR rate of 27.5%. Concordant classification occurred in 180 (76.3%) cases: 19 cases where both sources indicated B-CPR was performed and 161 where both indicated it was not. Discrepancies occurred in 56 cases (23.7%), including 46 instances where 9-1-1 audio identified B-CPR but EMS did not, and 10 where EMS documented B-CPR but audio review did not. Among the 46 audio-confirmed cases not captured by EMS, most involved B-CPR that ended before EMS arrival (e.g., B-CPR was discontinued by the caller), and 7 appeared to be EMS misclassifications. In the 10 cases where EMS documented B-CPR but audio did not, all involved calls that ended prior to EMS arrival without recognition of OHCA or B-CPR instruction. Overall agreement was fair to moderate: Cohen's kappa = 0.28 [95%CI 0.15, 0.42], Gwet's AC1 = 0.65 [95%CI 0.56, 0.75]), and McNemar's test showed significant asymmetry in classification, p < 0.001. CONCLUSIONS: The provision of B-CPR differed in nearly 25% of OHCA cases when comparing EMS documentation with 9-1-1 audio review. Most discrepancies resulted from early termination of B-CPR by the caller prior to EMS arrival, while a smaller proportion appeared to reflect EMS misclassification. These findings underscore the importance of sustained telecommunicator CPR instruction through EMS arrival at the patient's side.