Comparison of manually triggered ventilation and bag-valve-mask ventilation during cardiopulmonary resuscitation in a manikin model

Background

To compare a novel, pressure-limited, flow adaptive ventilator that enables manual triggering of ventilations (MEDUMAT Easy CPR, Weinmann, Germany) with a bag-valve-mask (BVM) device during simulated cardiac arrest.

Methods

Overall 74 third-year medical students received brief video instructions (BVM: 57 s, ventilator: 126 s), standardised theoretical instructions and practical training for both devices. Four days later, the students were randomised into 37 two-rescuer teams and were asked to perform 8 min of cardiopulmonary resuscitation (CPR) on a manikin using either the ventilator or the BVM (randomisation list). Applied tidal volumes (V_T), inspiratory times and hands-off times were recorded. Maximum airway pressures (P_max) were measured with a sensor connected to the artificial lung. Questionnaires concerning levels of fatigue, stress and handling were evaluated. V_T, pressures and hands-off times were compared using t-tests, questionnaire data were analysed using the Wilcoxon test.

Results

BVM vs. ventilator (mean ± SD): the mean V_T (408 ± 164 ml vs. 315 ± 165 ml, p = 0.10) and the maximum V_T did not differ, but the number of recorded V_T < 200 ml differed (8.1 ± 11.3 vs. 17.0 ± 14.4 ventilations, p = 0.04). P_max did not differ, but inspiratory times (0.80 ± 0.23 s vs. 1.39 ± 0.31 s, p < 0.001) and total hands-off times (133.5 ± 17.8 s vs. 162.0 ± 11.1 s, p < 0.001) did. The estimated levels of fatigue and stress were comparable; however, the BVM was rated to be easier to use (p = 0.03).

Conclusion

For the user group investigated here, this ventilator exhibits no advantages in the setting of simulated CPR and carries a risk of prolonged no-flow time.