Relationship between drowning location and outcome after drowning-associated out-of-hospital cardiac arrest: nationwide study

Abstract

Purpose: Accidental drowning can cause out-of-hospital cardiac arrest (OHCA). We investigated the effect of drowning location on outcomes of individuals who experienced drowning-OHCA.

Methods: All cases of emergency medical service-treated drowning-OHCA in South Korea from January 2006 to December 2013 were analyzed. Cases were excluded if there was a preceding injury, no information on event location, or suicide. Cases were divided into 4 groups: recreational water with mandatory safety regulations (group 1, public swimming pool; group 2, beach) and nonrecreational water without mandatory safety regulations (group 3, natural freshwater; group 4, seawater). The main outcome was survival to hospital discharge. Multiple logistic regression analysis was conducted using natural freshwater as the reference location.

Results: We analyzed 1691 drowning-OHCAs (public swimming pools, 3.4%; public beaches, 5.2%; unsupervised seawater, 33.8%; and unsupervised open freshwater, 57.6%). The rate of survival to discharge was 4.6% for all cases, 17.5% for cases in public swimming pools, 9.1% for cases in public beaches, 4.9% for cases in unsupervised seawater, and 3.3% for cases in unsupervised open freshwater (p<0.01). The adjusted odds ratios (95% confidence intervals [CIs]) for survival relative to natural freshwater were 3.97 (95% CI, 1.77-8.89) for public swimming pools, 2.81 (95% CI, 1.22-6.45) for public beaches, and 1.54 (95% CI, 0.88-2.70) for unsupervised seawater.

Conclusion: Individuals who experience drowning-OHCA in public locations with safety regulations had a better rate of survival. There should be improved public awareness of the significantly greater risk of drowning-OHCA in locations that have no safety regulations.