Effect of bystander cardiopulmonary resuscitation type on 1-month survival in drowning following out-of-hospital cardiac arrest in natural water bodies: a nationwide retrospective cohort study.
Resuscitation · 2026-04-01 · Registry study
Abstract
AIM: This study aimed to examine the total causal effect of bystander cardiopulmonary resuscitation (BCPR) type and 1-month survival in cases of drowning following out-of-hospital cardiac arrest (OHCA) in natural water bodies. METHODS: This retrospective cohort study used the Utstein style database and the Emergency Transport Registry of Japan from 2016 to 2022. We included cases of drowning following OHCA in natural water bodies (e.g., sea, river/pond). BCPR was categorized as no-BCPR, hands-only CPR (chest compressions only), and conventional CPR (chest compressions with rescue breathing). Multivariable logistic regression analysis was used to estimate adjusted odds ratios (AORs) and 95% confidence intervals (CIs). RESULTS: A total of 3914 patients were eligible for analysis (no-BCPR, n = 2633 [67.3%]; hands-only CPR, n = 1049 [26.8%]; conventional CPR, n = 232 [5.9%]). The proportion of 1-month survival was 2.7% for no-BCPR, 9.4% for hands-only CPR, 24.1% for conventional CPR. Multivariable logistic regression analysis revealed that compared with no-BCPR, both conventional CPR (AOR [95% CI], 3.70 [2.31-5.93]) and hands-only CPR (AOR [95% CI], 1.74 [1.19-2.54]) were positively associated with 1-month survival. Furthermore, hands-only CPR and conventional CPR was positively associated with 1-month survival (AOR [95% CI], 2.13 [1.41-3.23]). CONCLUSION: In cases of drowning following OHCA in natural water bodies, both conventional CPR and hands-only CPR indicated a beneficial causal effect on 1-month survival compared to no-BCPR, with conventional CPR showing greater causal effect. These findings support prioritizing conventional CPR for drowning following OHCA in natural water bodies.