Association of small adult ventilation bags with return of spontaneous circulation in out of hospital cardiac arrest.

Introduction: Little is known about the impact of tidal volumes delivered by emergency medical services (EMS) to adult patients with out-of-hospital cardiac arrest (OHCA). A large urban EMS system changed from standard adult ventilation bags to small adult bags. We hypothesized that the incidence of return of spontaneous circulation (ROSC) at the end of EMS care would increase after this change.
Methods: We performed a retrospective analysis evaluating adults treated with advanced airway placement for nontraumatic OHCA between January 1, 2015 and December 31, 2021. We compared rates of ROSC, ventilation rate, and mean end tidal carbon dioxide (ETCO ₂ ) by minute before and after the smaller ventilation bag implementation using linear and logistic regression.
Results: Of the 1,994 patients included, 1,331 (67%) were treated with a small adult bag. ROSC at the end of EMS care was lower in the small bag cohort than the large bag cohort, 33% vs 40% (p = 0.003). After adjustment, small bag use was associated with lower odds of ROSC at the end of EMS care [OR 0.74, 95% CI 0.61 - 0.91]. Ventilation rates did not differ between cohorts. ETCO ₂ values were lower in the large bag cohort (33.2 ± 17.2 mmHg vs. 36.9 ± 19.2 mmHg, p < 0.01).
Conclusion: Use of a small adult bag during OHCA was associated with lower odds of ROSC at the end of EMS care. The effects on acid base status, hemodynamics, and delivered minute ventilation remain unclear and warrant additional study.
Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: This research did not receive any external funding. Robert Walker is a biomedical engineer employed by Stryker Emergency Care. Nicholas Johnson receives research funding from National Institutes of Health, Centers for Disease Control and Prevention, and University of Washington Royalty Research Fund for unrelated work and serves on a Scientific Advisory Board for Neuroptics, Inc. Thomas Rea has received support from Philips. Michael Sayre has received consulting fees from Stryker Emergency Care. The remaining authors have no conflicts of interest to report.
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