A randomised controlled trial comparing the effects of in-hospital and home-based methods of adjusting non-invasive ventilation settings in people with long-term breathing failure.

All participants will undergo a standardised daytime titration of NIV (using Vivo 45LS ventilator [Breas Medical, Massachusetts, United States of America]), followed by a four-week acclimatisation period (Week 0 to Week 4). After this period, participants who are not successfully using NIV will be randomised to one of three study arms. These participants will complete a single overnight sleep study assessment and NIV adjustments corresponding to their study arm during the adjustment period (Week 5 to Week 8). Randomised participants may undergo additional overnight sleep studies if deemed necessary by the clinician reviewing the sleep study to improve NIV usage. Participants successfully using NIV after the acclimatisation period (Week 0 to Week 4) will not be randomised and therefore will not undergo a sleep study during the adjustment period (Week 5 to Week 8). All participants will be asked to continue using NIV as prescribed during the adjustment period (Week 5 to Week 8) and the follow up period (Week 9 to Week 16). All participants will complete a home-based review of summarised overnight NIV and respiratory data (approximately 10 hours) at end-intervention (Week 16). Participants who are not randomised at Week 4 (post-recruitment) will not be included in the primary analysis. All participants (randomised and non-randomised participants) will be included in an observational analysis (lower grade of evidence) comparing outcomes at end-intervention (Week 16). Arm 2: Intervention Participants randomised to Arm 2 will complete a home-based polygraphy sleep study (approximately 10 hours), with adjustments to NIV settings based on breath-by-breath analysis. On the day of the sleep study, participants will attend a telehealth assessment with a respiratory doctor, who will make any required adjustments to the NIV mask and/or settings as deemed necessary. An experienced sleep scientist will set up the polygraphy sleep study equipment in the participant's home for the participant to wear and sleep with overnight. Measurements will include thoracic and abdominal respibands, continuous oxygen saturation (SpO2) using a pulse oximeter with a finger probe, and transcutaneous carbon dioxide (PtcCO2) using transcutaneous capnography. Mask pressure, total flow, tidal volume and leak will be measured by the NIV device. The sleep study data will be analysed by experienced clinicians to determine optimal NIV settings based on breath-by-breath analysis within 72 hours of the sleep study. The optimal NIV settings will be applied and sleep study equipment will be collected during a home-visit session with a respiratory nurse. Arm 3: Intervention Participants randomised to Arm 3 will complete a home-based review of summarised overnight NIV and respiratory data (approximately 10 hours). On the day of the review, participants will attend a telehealth assessment with a respiratory doctor, who will make any required adjustments to the NIV mask and/or settings as deemed necessary. Participants will set up continuous SpO2 monitoring themselves using a pulse oximeter with a finger probe. Mask pressure, total flow, tidal volume and leak will be measured by the NIV device. Experienced clinicians will determine optimal NIV settings based on summarised, whole-night NIV data, analysed within 72 hours of NIV data collection. The optimal NIV settings will be applied through a second telehealth session with a respiratory nurse.