RESUMO
Background: A non-invasive ventilation (NIV) mask has been designed to deliver NIV with expiratory washout (EW) to improve efficacy of ventilation by optimizing clearance of expired gases from the anatomic dead-space. This study compared the performance and comfort of a novel investigational mask with EW with a conventional mask during NIV therapy.Methods: In this pilot cross-over study, participants with severe stable chronic obstructive pulmonary disease (COPD) attended a single visit to receive bi-level NIV through two masks; the investigational mask with EW, and a conventional mask. The order of mask use was randomly allocated, and each mask was used for 60-minutes with a 30-to-60-minute washout in between. The primary outcome was transcutaneous carbon dioxide (PtCO2) at 60 minutes. Other physiologic and NIV device variables were also assessed.Results: The mean difference [95% CI] in the PtCO2 between the investigational and conventional masks at 60 minutes, adjusted for baseline, was -0.74 mmHg [-2.81 to 1.33, P=0.45]. The investigational mask with EW elicited a lower tidal volume (-128.7 mL [-190.0 to -67.3], P<0.001) and minute ventilation (-2.28 L·min-1 [-3.12 to -1.43], P<0.001), and a higher leak (7.96 L·min-1 [4.39 to 11.54], P<0.001), than the conventional mask. There were no significant differences in other physiological responses or ratings of dyspnoea or comfort.Conclusions: NIV therapy delivered using a novel mask with EW was similarly effective at reducing PtCO2, while the delivered tidal volume and minute ventilation were significantly lower, when compared to a conventional mask in participants with severe COPD.