Decreasing peak flow rate with a new bag-valve-mask device: effects on respiratory mechanics, and gas distribution in a bench model of an unprotected airway

Reducing inspiratory flow rate and peak airway pressure may be important in order to minimise the risk of stomach inflation when ventilating an unprotected airway with positive pressure ventilation. The purpose of this study was to assess the effects of a newly developed bag-valve-mask device (SMART BAG ®, O-Two Systems International, Ont., Canada) that limits peak inspiratory flow. A bench model simulating a patient with an unintubated airway was used consisting of a face mask, manikin head, training lung (lung compliance, 100 ml/cm H 2O, airway resistance 4 cm H 2O/l/s, lower oesophageal sphincter pressure 20 cm H 2O and simulated stomach). Twenty nurses were randomised to each ventilate the manikin using a standard single person technique for 1 min (respiratory rate, 12/min) with either a standard adult self-inflating bag, or the SMART BAG ®. The volunteers were blinded to the experimental design of the model until completion of the experimental protocol. The SMART BAG ® vs. standard self-inflating bag resulted in significantly ( P