Descriptive Characteristics of Drowning-Related Out-of-Hospital Cardiac Arrest in Marine Leisure Activities on a Japanese Island

Introduction Drowning is a global public health concern, with over 300,000 deaths annually. In Japan, approximately 700 drowning-related fatalities occur each year, increasingly involving older adults during marine leisure activities. However, limited data are available on the clinical characteristics of such incidents at tourist destinations. This study describes the characteristics and outcomes of drowning-related out-of-hospital cardiac arrest (OHCA) cases on a remote tourist island in Japan. Methods This retrospective, single-center descriptive case series reviewed OHCA cases due to drowning at Yaeyama Hospital between June 2021 and December 2023. Patient demographics, incident details, and outcomes were collected. Key variables included age, type of activities, bystander cardiopulmonary resuscitation (CPR), instructor presence, time to hospital arrival, and neurological outcomes based on the Cerebral Performance Category (CPC) scale. Results Among 31 OHCA cases, 90% (28 cases) involved tourists. The median age was 50 years, with most incidents related to snorkeling (10 cases) or scuba diving (9 cases). Bystander CPR was performed in 14 cases; 7 patients achieved return of spontaneous circulation. Instructors were present in 9 adult cases; however, whether they performed CPR could not be confirmed. At discharge, one adult had a CPC score of 1, and one had CPC 4. All 5 pediatric patients had CPC 1. The mean time from incident recognition to hospital arrival was 52 min. Conclusion This case series highlights demographic and situational patterns in drowning-related OHCA during marine activities. Further research is needed to identify risk factors and improve prevention strategies in resource-limited island settings.