Severe escalation of out-of-hospital cardiac arrests in sars-cov-2-immersed metropolitan cities

INTRODUCTION: Following COVID-19 stay-at-home directives in March 2020, many EMS systems worldwide observed 30- 40% decreases in total call volumes. Simultaneously, most metropolitan cities severely impacted by COVID-19 also reported marked increases in out-of-hospital cardiac arrest (OHCA) cases. The study aim was to quantify the change in OHCA numbers observed in large urban centers during the onset of the COVID-19 crisis. METHODS: Major city EMS systems covering ∼one-quarter of the U.S. population (n=45), and millions of others in major European/Australian cities, were surveyed for their monthly EMS OHCA numbers during the first 6 months of 2020. Data were compared to averaged corresponding monthly periods in 2018 and 2019. Considering normal variation and the complexities of OHCA cases (risk, significant personnel/resource utilization and protracted time away from other 9-1-1 responses), >10% increase/decrease was considered, a priori, a highly significant difference, especially in terms of operational impact. RESULTS: Of the 45 major U.S. cities studied, large escalations in OHCA were associated with the relative prevalence of COVID-19. During April, 32 cities with high rates of COVID-19 had >15% increases in OHCA vs. prior years. Among 13 cities with >50% (1.5-fold) increases, 3 widely recognized COVID-19 epicenters had >double their usual OHCA numbers (2.5-fold in NYC). Conversely, despite lockdowns, cities with relatively lower COVID-19 cases, had no change from prior years (n=6) or even fewer cases (n=6). Inclusive of all 45 cities, the mean number of OHCA cases/city rose in April by 62%, from 149 to 241 (p=0.037). By June, cities with the highest rates of OHCA, like NYC, returned to or approached pre-COVID levels after mitigating spread, while initial low impact cities with lower OHCA rates in April (eg, Phoenix, Charleston) experienced marked increases in June as local COVID-19 cases rose substantially. European/Australian cities mirrored the U.S. experience. CONCLUSIONS: Metropolitan cities have experienced marked increases in OHCA during 2020 paralleling the prevalence of COVID-19 in their respective jurisdictions placing significant operational strains on affected 9-1-1 systems. These on-going observations are now part of a work in progress to elucidate the underlying etiologies.