In this study, patients who were not compliant with NPPV included those who could not tolerate NPPV, those who failed NPPV and were invasively ventilated, and those who self-weaned because they thought they no longer needed NPPV. (32) Both of these studies suggest that compliance decreases over time, even over short periods of time such as 3 days.Plant et al (32) also reported mask comfort using a