Introduction: Emergency Medical Services (EMS) professionals rely on the bag-valve-mask (BVM) to provide life-saving positive-pressure ventilation in the prehospital setting. Multiple emergency medicine and critical care studies have shown that lung-protective ventilation protocols reduce morbidity and mortality. A recent study has shown that the volumes typically delivered by EMS professionals with the adult BVM are often higher than recommended by lung-protective ventilation protocols. Our primary objective was to determine if a group of EMS professionals could reduce the volume delivered by adjusting the way the BVM was held. Secondary objectives included 1) if the adjusted grip allowed for volumes more consistent with lung-protection ventilation strategies and 2) comparing volumes to similar grip strategies used with a smaller BVM.
Methods: A patient simulator of a head and thorax was used to record respiratory rate, tidal volume, peak pressure, and minute volume delivered by participants for 1 minute each across 6 different scenarios: 3 different grips (using the thumb and either 3 fingers, 2 fingers, or one finger) with 2 different sized BVMs (adult and pediatric). Trials were randomized by blindly selecting a paper with the scenario listed. A convenience sample of EMS providers was used based on EMS provider and research staff availability.
Results: We enrolled 50 providers from a large, busy, urban hospital-based EMS agency a mean 8.60 (SD = 9.76) years of experience. Median volumes for each scenario were 836.0 mL, 834.5 mL, and 794 mL for the adult BMV (p = 0.003); and 576.0 mL, 571.5 mL, and 547.0 mL for the pediatric BVM (p < 0.001). Across all 3 grips, the pediatric BVM provided more breaths within the recommended volume range for a 70 kg patient (46.4% vs. 0.4%; p < 0.001) with only a 1.1% of breaths below the recommended tidal volume.
Conclusion: The study suggests that it is possible to alter the volume provided by the BVM by altering the grip on the BVM. The tidal volumes recorded with the pediatric BVM were above recommended range in 2 of the 3 grips. The volumes of the pediatric BVM were overall more consistent with lung-protective ventilation volumes when compared to all 3 finger-grips of the adult BVM.
Keywords: BVM; EMS; lung-protective ventilation; prehospital.