To determine the effectiveness of ventilations in bystander cardiopulmonary resuscitation (BCPR) and to identify the factors associated with ventilation-only BCPR. From out-of-hospital cardiac arrest (OHCA) data prospectively collected from 2005 to 2011 in Japan, we extracted data for 210,134 bystander-witnessed OHCAs with complete datasets but no prehospital involvement of physician [no BCPR, 115,733; ventilation-only, 2093; compression-only, 61,075; and conventional (compressions+ventilations) BCPR, 31,233] and determined the factors associated with 1-month neurologically favourable survival using simple and multivariable logistic regression analyses. In 91,885 patients with known BCPR durations, we determined the factors associated with ventilation-only BCPR. The rate of survival in the no BCPR, ventilation-only, compression-only and conventional group was 2.8%, 3.9%, 4.5% and 5.0%, respectively. After adjustment for other factors associated with outcomes, the survival rate in the ventilation-only group was higher than that in the no BCPR group (adjusted OR; 95% CI, 1.29; 1.01-1.63), but lower than that in the compression-only (0.76; 0.59-0.96) or conventional groups (0.70; 0.55-0.89). Conventional CPR had the highest OR for survival in almost all OHCA subgroups. The adjusted OR (95% CI) for survival after dividing BCPR into ventilation and compression components was 1.19 (1.11-1.27) and 1.60 (1.51-1.69), respectively. Older guidelines, female sex, younger patient age, bystander-initiated CPR without instruction, early BCPR and short BCPR duration were associated with ventilation-only BCPR. Ventilation is a significant component of BCPR, but alone is less effective than compression in improving neurologically favourable survival after OHCAs.

Background The impact of the coronavirus disease 2019 (COVID-19) pandemic on out-of-hospital cardiac arrest (OHCA) occurring in this setting remains unclear. Objective The objective of this study is to elucidate the impact of the COVID-19 pandemic on the prehospital characteristics and outcomes of OHCA occurring in the workplace. Methods This nationwide observational study in Japan was a retrospective analysis and included 16,364 non-emergency medical service witnessed and adult workplace OHCAs. The characteristics and outcomes of workplace OHCAs were compared between the pre-pandemic period (2016-2019) and the pandemic period (2020-2021). Furthermore, subgroup analyses were performed for workplace location (office vs. non-office) and infection burden region. Results During the pandemic period, no significant changes were observed in incidence, public access defibrillation (PAD) provision rates, one-month survival rates, or neurologically favorable survival rates. However, increases were observed for bystander cardiopulmonary resuscitation (CPR) (crude odds rate (cOR), 95% confidence interval (CI): 1.10, 1.02-1.16; P<0.001), particularly compression-only CPR. The multivariable analysis revealed that the impact of the pandemic was similarly seen in an increase in bystander CPR (adjusted OR, 95% CI: 1.14, 1.06-1.22; P<0.001). Furthermore, the monthly changes in only PAD were altered biennially (PAD: P=0.02, bystander CPR: P=0.52, one-month survival: P=0.26, and neurologically favorable one-month survival: P=0.48). Analysis restricted to high-infection burden regions revealed that only the PAD rate decreased (P=0.03). Conclusion The COVID-19 pandemic had no impact on OHCA survival in workplaces and had a limited positive impact on bystander responses. This may be attributed to previous positive CPR training experiences and routine preparation for health crises.