An anaesthetist who was blinded to all monitor tracings ventilated the lungs of 40 apnoeic patients during routine anaesthesia induction either with a standard bag-valve device or with the mouth-to-bag resuscitator in a random order. Study endpoints were peak inspiratory flow rates, peak airway pressure, tidal volumes and inspiratory time.
Peak inspiratory flow was 40 ± 10 l min−1 for the standard bag-valve device versus 33 ± 13 l min−1 for the mouth-to-bag resuscitator (P < 0.0001); peak airway pressure was 17 ± 5 cmH2O versus 14 ± 5 cmH2O (P < 0.0001); inspiratory tidal volume was 477 ± 133 ml versus 644 ± 248 ml (P < 0.001) and inspiratory time was 1.1 ± 0.3 s versus 1.9 ± 0.6 s (P < 0.0001).
Employing the mouth-to-bag resuscitator during simulated ventilation of a non-intubated patient in respiratory arrest significantly decreased peak inspiratory flow and peak airway pressure and increased inspiratory tidal volume and inspiratory times compared to a standard bag-valve device.