This study will be a randomized crossover trial that will be conducted at Rush University. Normal volunteers will be recruited from Rush University Medical Centers. Volunteers will be screened with inclusion and exclusion criteria and an informed consent is required in order for them to participate.
Also, initial baseline vital signs (heart rate, blood pressure, respiratory rate, and oxygen saturation) will be obtained. EtCO2 will be obtained at baseline and periodically using an oral/nasal sample line with the CapnostreamTM 20p monitor (Medtronic, Minneapolis, MN). The study will use a double limb circuit ICU ventilator Puritan Bennett™ (Medtronic, Dublin, Ireland).
Investigators will evaluate 4 NIPPV masks (2 oronasal masks and 2 full face masks). Oronasal masks will be labeled as group A and numbered as A1 and A2; while full face masks will be labeled group B and numbered as B1 and B2. Order of the masks will be randomly chosen in two steps. First steps will be choosing A or B then randomly assign mask in each of these groups. Investigators will randomly assign mask in group A or B by drawing an initial mask from the group and then continue the sequence of masks from that point. For example, investigators randomly chose group A, then randomly chose A2, the sequence will be A2, A1. Then Investigators would randomly choose B2, then the sequence would be B2, B1. All subjects will perform 15 minutes on each mask followed by 5 minutes wash out interval between masks. EPAP levels will be 0, 2, 4, \& 5 while IPAP remains at 5 higher than EPAP. EtCO2 will be collected at 4:00, 4:30 and 5:00 minute mark. These three measures should differ by less than 20% of their average. Also, subjective mask ORA: 18011502-IRB01 Date IRB Approved: 3/30/2018 Amendment Date: 5/11/2018 comfort will be assessed via visual analog scale (VAS) with 1 referring to least comfortable and 5 being the most comfortable after 5 each EPAP setting.
