Determinants of bystander removal attempts in witnessed foreign body airway obstruction: a prospective nationwide multicenter observational study from the MOCHI registry.

Background: Foreign body airway obstruction (FBAO) is a time-critical emergency. Although bystander removal maneuvers can improve outcomes, they are not consistently attempted even when events are witnessed. We aimed to identify patient-, witness-, and setting-related factors associated with the absence of bystander removal attempts in witnessed FBAO. Methods: We analyzed a prospective, nationwide, multicenter cohort from the MOCHI registry in Japan, including patients with witnessed FBAO. The primary outcome was absence of a bystander removal attempt. Multivariable logistic regression with multiple imputation for missing data was used to examine associations with patient age, sex, eating function, location (home, care facility, public), and witness/bystander age and sex. Results: Among 325 witnessed FBAO events, 193 (59%) involved a removal attempt and 132 (41%) did not. The median patient age was 81 years. Attempt rates varied by location: 82% in care facilities, 52% at home, 43% in public places. Witnesses/bystanders were significantly older in events without an attempt (median 60 vs. 50 years). Older witness/bystander age was independently associated with higher odds of no attempt (OR 1.39 per 10-year increase; 95% CI 1.14-1.70). Compared with home, no attempt was less frequent in care facilities (OR 0.43; 95% CI 0.20-0.93) and more frequent in public places (OR 2.11; 95% CI 1.08-4.10). Conclusions: In witnessed FBAO, removal attempts were less likely when witnesses were older and when events occurred in public places. These findings may help inform age-tailored and setting-specific first-aid strategies to increase bystander intervention.