Characteristics and outcomes of out-of-hospital cardiac arrest due to drowning - a nationwide registry-based study.

AIM OF THE STUDY: To describe and compare cases of resuscitation after out-of-hospital cardiac arrest (OHCA) attributed to drowning (D-OHCA) versus other causes (ND-OHCA).

METHODS

Retrospective, descriptive and comparative analysis of D-OHCA vs. ND-OHCA patients registered in the German Resuscitation Registry from January 2013 to December 2023 using Chi-square, Mann-Whitney U tests and regression analysis. Key variables included 10-year age groups, body temperature measured at the scene, prehospital factors (e.g., bystander CPR, initial rhythm), and outcomes such as survival and neurological status (CPC, mRS) at hospital discharge.

RESULTS

Of the 68,719 included patients 316 (0.5%) had D-OHCA with 50% of the cases occurring during the summer months (June, July and August). D-OHCA in comparison to ND-OHCA patients were younger (median age 50 years vs. 72.5 years, p < 0.001), had a higher rate of asystole as initial rhythm (73.1 vs. 54.9%, p < 0.001) and a lower initial body temperature (median of 31.1 °C vs. 35.8 °C, p < 0.001). While overall survival and favourable neurological outcomes did not differ significantly between groups, stratified analysis showed that D-OHCA patients aged 0-10 years had significantly higher survival rates (44.7% vs. 16.3%, p < 0.001) and favourable neurological outcomes at hospital discharge (34.0% vs. 7.6%, p < 0.001) compared to ND-OHCA patients under 11 years.

CONCLUSION

Drowning was a rare cause of out-of-hospital cardiac arrest in this study, often occurring during summer months. Outcome in D-OHCA was generally comparable to ND-OHCA and only better in children aged up to 10 years. Lower body temperatures were associated with unfavourable outcomes in most D-OHCA cases.