Influence of mask design on bag-mask ventilation

Adequate positive pressure ventilation in the field or emergency department continues to represent a major challenge. A new face mask design that recently has been introduced consists of a low-pressure "balloon" through which a Guedel airway is attached and extended proximally through the mask to allow the attachment of a ventilation bag. The mask is designed to seal the nares and mouth when pressed against the face. Ventilation is achieved through the airway which extends through the mask to just above the epiglottis. We designed a study to evaluate ventilating volumes and mask leak with this mask design, and to compare these parameters with those achieved with standard masks. Thirty volunteers with varied experience in bag-mask ventilation were chosen to ventilate a specially adapted ventilation manikin connected to a test lung that was capable of simulating varied compliances. Spirometers measured volumes delivered to the ventilating bag and lung, and mask leak could be calculated from these readings. A constant rate of 12 ventilations per minute was maintained by each volunteer for two minutes. Volunteers ventilated the test lung using three masks in random sequence: the SealEasy mask (Respironics Inc, Monroeville, PA), a Laerdal mask (old type), and a transparent Robertshaw mask with inflatable black rim. The average tidal volume delivered by the SealEasy mask was consistently higher than either of the other two. Significantly (P less than .05) higher volumes were delivered with the SealEasy mask when compared to the Laerdal, and significantly lower mask leaks were seen when the SealEasy was compared to both.(ABSTRACT TRUNCATED AT 250 WORDS)