Noninvasive Ventilation Masks Carbon Dioxide Clearance in Normal Volunteers

Order of the masks (BiTrac MaxShield™ with standard elbow, BiTrac™ Full Face with standard elbow, Respironics PerforMax with standard elbow, and Respironics AF531 with standard elbow) were randomly chosen. Investigators randomly assigned all masks for paper raffling from container. All subjects performed 20 minutes on each mask followed by 5 minutes wash out interval between masks. EPAP levels will be 0, 2, 4, \& 5 (5 minutes for each level) while IPAP remains at 5 higher than EPAP. FiCO2 and EtCO2 were collected at 4:00, 4:30 and 5:00 minute mark for each EPAP level. Also, subjective mask comfort was assessed via visual analog scale (VAS) with 1 referring to least comfortable and 5 being the most comfortable after 5 each EPAP setting.