Objective

Manual ventilation is a basic skill that every emergency medical services (EMS) responder is expected to perform proficiently. Improper manual ventilation may result in significant morbidity; however, there is no feedback mechanism or method of control for the volume, pressure, or frequency during manual ventilation. In this study, we aimed to quantify the volume and peak pressures of manually delivered breaths using a simulated lung.

Methods

One hundred ninety-nine volunteer EMS responders from the EMS World Expo 2019 and EMS Today 2020 participated in this study. Each volunteer manually ventilated a simulated lung using a bag-valve-mask (BVM) for 18 breaths. Descriptive statistics were computed for peak pressures (P_peak) and tidal volumes (V_T)), and a multivariable linear regression was conducted to determine whether there was an independent correlation between P_peak or V_T and seven different variables.

Results

Both P_peak and V_T delivered by EMS responders had a high level of variability; 82.9% of clinicians delivered at least one breath exceeding the recommended safety thresholds; and 98.0% delivered at least one breath that was inadequate or excessive. Our results showed no likely clinical significant role of sex, hand size, frequency of use, or years of experience in determining P_peak and V_T. Tidal volumes were significantly higher in males (p < 0.001), those using two-hand manual ventilation (p < 0.001), shorter hand length (p = 0.013), higher confidence (p < 0.001), and more years of experience (p < 0.001). Peak pressures were significantly higher in those using two-hand manual ventilation (p < 0.001), wider hand width (p = 0.004), higher confidence (p < 0.001), less frequent use of the BVM per month (p < 0.001), more experience (p < 0.001).

Conclusions

Our study demonstrated large variability of V_T and P_peak within and, to a lesser degree, between clinicians. Of the seven variables that might have affected tidal volume or peak pressures, only the use of two hands versus one hand had a potentially clinically significant effect. Our study identifies a clear need for BVM improvement to ensure every practitioner can deliver breaths at appropriate volumes and safe pressures.