Non-invasive ventilation: Evaluation of CO<inf>2</inf> washout by intentional leaking in three recent oronasal masks. A pilot study

Médrinal, Clément Prieur, Guillaume Contal, Olivier Villiot-Danger, Estelle Doyle, Clare Reychler, Gregory [UCL] Quieffin, Jean

Background. Many types of interfaces with intentional leaks exist for Non Invasive Ventilation. The purpose of intentional leaks is to remove CO2 from the interface, however the calibration does not allow a sufficiently large flow and rebreathing of CO2 can occur. The aim of this study was to compare the CO2 rinsing capacities of three new generation oronasal masks with intentional leaks (A: Quattro®, [Resmed]; B: Amara® [Respironics]; C: Forma® [Fisher&Paykel]) in healthy subjects. Methods. Seventeen healthy volunteers were included in this prospective cross-sectional, randomized, double-blinded trial. Each subject underwent ventilation with a home ventilator (IPAP: 14 cmH2O; EPAP: 4 cmH2O) with each mask consecutively. Transcutaneous capnography (PtcCO2) recordings were carried out throughout the trial and ventilator data (tidal volume, respiratory rate, minute ventilation and unintentional leaks) were also analyzed. Mask comfort was assessed using a visual analog scale (0 to 10). Results. The results showed no differences in PtcCO2 between masks (P=0.82). There were no significant differences in respiratory parameters (tidal volume, P=0.79; respiratory rate, P=0.65; minute ventilation, P=0.12) between masks. The rate of unintentional leaks were significantly lower for Mask A (P=0.016). Subjects rated Mask A and Mask C as more comfortable than Mask B (P=0.041). Conclusion. There was no effect of mask on PtcCO2 in healthy subjects. The mask with the highest comfort rating had not the lowest rate of unintentional leaks.