The effect of inspiratory duration and chinstrap during non-invasive ventilation

This study is looking at how two adjustments — changing the length of each breath and using a chin strap — affect the quality of non-invasive ventilation (NIV) during sleep. NIV is a type of breathing support delivered through a mask worn at night, used by people with breathing problems due to conditions like neuromuscular disease, obesity, or COPD. Researchers want to find out which settings are most comfortable and effective for home users of NIV. You may be eligible if: - You have documented nighttime breathing difficulties (nocturnal hypoventilation) from any cause - You are already using a bilevel non-invasive ventilator at home at night - You are using a nasal mask with your ventilator - You have been using NIV for at least 5 hours per night consistently - You are able to attend the sleep laboratory for 3 nights over a 6-night period You may NOT be eligible if: - You have very limited arm movement that would prevent you removing your mask in an emergency - You have a significant psychiatric or psychological condition - You have had a respiratory illness in the last month - You are taking sleeping tablets or antidepressant medication Talk to your doctor about whether this trial might be right for you.