Comparison of prehospital tidal volume delivery performance between automated transport ventilators and bag-valve devices in out-of-hospital cardiac arrest patients: does the pressure limit matter?

内容摘要

Automatic transport ventilators (ATVs) are a potential option for ventilating patients experiencing out-of-hospital cardiac arrest (OHCA); however, their tidal volume delivery performance at different pressure limits compared with that of manual ventilation remains unclear. This retrospective study with quasi-experimental before-after features included adult patients with nontraumatic OHCA with prehospital advanced airway in Hsinchu county, Taiwan, in 2023. Participants were categorized into three groups: Group 1 (ventilated by ATVs; pressure limit: 45 cmH2O), Group 2 (ventilated by ATVs; pressure limit: 60 cmH2O), and Group 3 [manual ventilation by bag-valve devices (BVDs)]. The inspiratory tidal volume measured using Zoll® X-series monitors after advanced airway placement in each group was compared using a linear mixed-effect model (LMM). The association between ventilation settings, delivered inspiratory tidal volume, and return of spontaneous circulation (ROSC) was investigated using logistic regression. Groups 1, 2, and 3 comprised 41 (23.0%), 80 (44.9%), and 57 (32.0%) patients with OHCA, respectively. In the post-hoc LMM analysis, Group 1 had a significantly higher tidal volume than Group 2 (adjusted difference: 66.84 mL, 95% confidence interval: 21.27-112.42, p = 0.012). However, no significant differences were found between Groups 1 and 3 or between Groups 2 and 3. No significant association was observed between different ventilation settings or delivered inspiratory tidal volume and prehospital ROSC or any ROSC following resuscitation. ATVs demonstrated comparable delivered inspiratory tidal volume to BVD ventilation in this exploratory retrospective cohort. Increasing the pressure limit of ATVs from 45 to 60 cmH2O did not increase delivered inspiratory tidal volume. The optimal pressure settings of ATVs, formal feasibility and implementation outcomes, and their effects on clinical outcomes remain unclear and require prospective validation.