Law Enforcement Often Arrive First on Scene at Out-of-Hospital Cardiac Arrest in an Underserved County in Michigan

Early initiation of CPR can improve outcomes in out-of-hospital cardiac arrest (OHCA). In Genesee County, MI, an underserved region reported to have low rates of bystander CPR, non-EMS first-responders (FRs) like police and fire have the potential to bridge the gap between 911 activation and EMS arrival. Our objectives were to determine how often FRs are closest to the scene at the time of initial 911 call and to identify appropriate metrics for potential intervention, including the percent of cases in which the closest unit: 1. is dispatched, 2. arrives first on scene, and 3. initiates CPR.

Trained abstractors reviewed CARES registry and 911 dispatch data to identify appropriate OHCA cases for the period 1/1/2022-12/31/2023. Cases with missing data, those with delayed recognition or occurrence of cardiac arrest, and arrests in extended care facilities (ECF) were excluded. GPS location data, unit dispatch and arrival times, and pre-hospital CPR were abstracted in duplicate, with disagreements adjudicated by third review. Two-tailed Student’s t tests were used to determine statistical significance of differences between groups.

Out of 1109 OHCA cases, 103 (9.3%), 199 (17.9%), and 48 (4.3%) were excluded due to missing data, delayed CA, or ECF arrest, respectively. Of the remaining 759 OHCAs, police, fire, and EMS were closest to the scene in 293 (38.6%), 238 (31.4%), and 228 (30%) cases. When closest, police were 2.4+/-1.7 miles away vs. 5.9+/-3.1 for EMS (p < 0.001) and were dispatched 82.6% of the time. Despite a call-to-dispatch time of 4.0+/-3.8 min vs. 1.3+/-0.5 min for EMS (p < 0.01), police arrived on scene first in 89.6% of cases, an average of 6.2 (IQR 1.4-7.2) minutes earlier than EMS. Fire was always dispatched when closest and had a mean call-to-dispatch of 1.8+/-0.5 min, but arrived on scene first in only 50% of cases. 911 dispatch data rarely documented who performed CPR on scene, although available CARES data indicates low rates of police-initiated CPR.

Non-EMS FRs were closest to the scene in 70% of relevant OHCA cases in Genesee County from 2022-2023. Police, in particular, arrived on scene first in almost all cases in which they were closest, despite a significant delay in dispatch. Our results indicate potential opportunity for expedited response through utilization of FRs and provide accessible metrics for larger studies and intervention-based trials.