Abstract Sun702: Unexpected Delays: Breathing Diagnostic Tool Associated with Compression Interruptions Without Clear Survival Benefits

Introduction: The Medical Priority Dispatch System (MPDS) includes a Breathing Verification Diagnostic Tool (BVDxT) to help emergency dispatchers assess breathing effectiveness in suspected cardiac arrest and identify the need for chest compressions. However, the use of a breathing diagnostic tool may delay critical chest compression initiation. Hypothesis: We hypothesize that the breathing diagnostic tool may delay the start of chest compressions in cardiac arrest. Objective: This study aims to determine if a breathing diagnostic tool impacts time to first chest compression and key patient outcomes, including cardiac arrest recognition, return of spontaneous circulation (ROSC), and survival to hospital discharge. Methods: We conducted a retrospective cohort study of cardiac arrests treated by the Salt Lake City Fire Department from August 2016 to February 2025. We excluded cases with undocumented breathing status or breathing diagnostic tool use, or those initially identified as not breathing. We compared outcomes between patients where the breathing diagnostic tool was used versus not used. Results: Of 1,016 cardiac arrests, possibly abnormal breathing was identified in 379 emergency calls. The tool was used in 164 patients and not used in 167; 48 cases had missing data. Baseline cardiac arrest characteristics were similar between groups, though bystander CPR was more frequent in the breathing diagnostic tool group (60.3% vs. 46.0%, p=0.01). Interruptions in ongoing chest compressions occurred in 17.7% (28/164) of cases and time to dispatcher recognition of arrest was longer when the breathing diagnostic tool was performed (2.8 min in non-BVDxT group vs. 3.5 min in BVDxT group, p=0.01). No significant difference was found in time to first chest compression (4.0 min in non-BVDxT group vs. 4.5 min in BVDxT group, p=0.19). Multivariable linear regression did not demonstrate an association of breathing diagnostic tool use and shorter time to first chest compression (coefficient 14.9, p=0.45, 95% CI, -23.487- 53.281). Similarly, no association was observed between breathing diagnostic tool use and ROSC (adjusted odds ratio 1.25, 95% CI 0.792-1.983, p=0.33) or survival (adjusted odds ratio, 0.91, 95% CI 0.504-1.647, p=0.76). Conclusion: In this single center EMS agency, the breathing verification diagnostic tool did not significantly affect time to first chest compression, ROSC, or survival to hospital discharge for cardiac arrest patients.