Impact Of Different Leak Valves On CO₂ Pressure Adjacent To The Nasal Mask In Healthy Volunteers Amid Noninvasive Positive Pressure Ventilation

Objective:To explore the impact of the intended air leaks with a single hole port and with a plateau exhalation valve on CO2 pressure inside the air circuit adjacent to nasal masks amid noninvasive positive pressure ventilation(NIPPV)in healthy volunteersMethods: Twelve healthy volunteers(mean age 26.70±3.30 years, M:F=1:1)were recruited in the open-lable, cross-over study. The subjects were connected to a non-invasive ventilator(Philips Trilogy 100) via a nasal mask. A single hole port or a plateau exhalation valve was randomized linked to the masks. A capnometer was sequencially linked to the leak device. The setting of the ventilator was as the following: phase switch mode was S/T; the IPAP and EPAP were 12 cm H2O and 5cm H2 O respectively; back-up respiratory rate was10 beats/min,, inspiratory/expiratory ratio was 1:2. Each subject was test with a single hole port and a plateau valve in a rondmonly sequence.Results: The PETCO2 in the proximal circuit with the single hole leak was lower than that with the plateau valve leak(23.80 ± 4.00 cm H2O vs. 29.9 ±4.38 cm H2O, P<0.05)Conclusion: The plateau valve has less CO2 retention in the proximal end of the air circuit, indicating less CO2 would be rebreathed during NIPPV treatment.