Astral VAPS AutoEPAP Clinical Trial

Inclusion criteria for the study are: 1. Participant has ability to provide written informed consent 2. Participants aged ≥18 years old 3. Participant has documented respiratory failure (e.g. sleep hypoventilation with historical PtCO2 increase ≥ 10mmHg) and/or daytime hypercapnia (\>45 mmHg) 4. Participant is currently using non-invasive positive pressure ventilation in ST or VAPS mode for ≥ 3 months 5. Participants with a previously documented AHI ≥ 5/hr 6. Participants with a recently (≤ 12 months ago) reviewed EPAP setting Exclusion criteria for the study are: 1. Participants are not compliant on NIPPV (e.g. \< 4 hr/night) 2. Participants who are pregnant 3. Participants on oxygen therapy ≥5 L/min 4. Participants with an invasive interface (e.g. tracheostomy) 5. Participants who have had an acute exacerbation within the last 3 months that resulted in a hospitalisation 6. Participants who are acutely ill, medically complicated or who are medically unstable 7. Participants in whom NIPPV therapy is otherwise medically contraindicated 8. Participants who have had surgery of the upper airway, nose, sinus, or middle ear within the previous 90 days 9. Participants with untreated, non-OSA sleep disorders, including but not limited to; insomnia, periodic limb movement syndrome, or restless legs syndrome. 10. Participants who have the following pre-existing conditions: severe bullous lung disease, recurrent pneumothorax or pneumomediastinum, cerebrospinal fluid leak, recent cranial surgery or trauma. 11. Participant does not comprehend English 12. Participant is unable or unwilling to provide written informed consent 13. Participant is physically and/or mentally unable to comply with the protocol 14. Participant is not suitable to participate in the trial for any other reason in the opinion of the investigator