Abstract
OBJECTIVES: This study aimed to determine whether the association between conventional bystander cardiopulmonary resuscitation (BCPR) and better outcomes in drowning-associated out-of-hospital cardiac arrest (OHCA) differs between young and older people or between non-medical and medical drowning in Japan. DESIGN: Observational study. SETTING: This study used data from the Japanese Fire and Disaster Management Agency databases. PARTICIPANT: Of the 504 561 OHCA cases recorded in the nationwide database between 2016 and 2019, 16 376 (3.2%) were presumably caused by drowning. MAIN OUTCOME MEASURE: The main outcomes were a 1-month neurological prognosis defined as cerebral performance category 1 or 2 and 1-month survival as measures. RESULT: The incidence of drowning as a presumed cause of OHCA was high in the winter and the middle-aged and older generations in Japan. However, OHCA caused by drowning in the younger generation frequently occurs in the summer. Furthermore, younger patients had higher incidences of bystander-witnessed cardiac arrest (22.0%), BCPR provision (59.3%) and arrest in outdoor settings (54.0%) than middle-aged and older generations (5.9%, 46.1% and 18.7% respectively). If the patient was younger or the arrest was accidental, the conventional BCPR group had better neurological outcomes than the compression-only BCPR group (95% CI of adjusted OR, 1.22 to 12.2 and 1.80 to 5.57, respectively). However, in the case of middle-aged and older generations and medical categories, there was no significant difference in outcomes between the two types of BCPR. This conventional group's advantage was maintained even after matching. CONCLUSION: Conventional bystander CPR yielded a higher neurologically favourable survival rate than compression-only BCPR for OHCA caused by drowning if the patient was younger or the arrest was non-medical. Conventional CPR education for citizens who have the chance to witness drownings should be maintained.