Spatial variation in neurological outcomes after shockable out-of-hospital cardiac arrest in central Tokyo: a single-center retrospective study

In urban areas, abundant medical resources improve outcomes for patients with out-of-hospital cardiac arrest (OHCA). However, metropolitan environments present unique pre-hospital transportation challenges rarely observed in rural areas, such as complex transportation networks and high-rise buildings. Additionally, social factors, such as economic disparities within the same city, may affect prognostic outcomes. The aim of this study was to explore the spatial variation in neurological outcomes and prehospital time intervals among patients with shockable OHCA transported to a tertiary emergency center in central Tokyo. In this retrospective, observational study, data regarding patients transported to Tokyo Medical and Dental University Hospital between June 1, 2016 and May 30, 2022 were extracted from electronic records. Bayesian spatial modeling was used to examine spatial variation in neurological outcomes and prehospital time intervals. Associations between EMS on-scene time, transport time, and neurological outcomes were also examined. Exploratory spatial patterns were observed in relation to distance from the OHCA scene to the emergency center, building floor information, and area-level contextual indicators such as land price. In this single-center cohort of patients with shockable OHCA transported to a tertiary emergency center in central Tokyo, neurological outcomes and prehospital time intervals showed spatial variation. These findings should be interpreted as exploratory and hypothesis-generating, and larger multicenter studies are needed to confirm their generalizability.