Raising the head of the bed to 30 degrees for adults with snoring and obstructive sleep apnoea

INTERVENTION: Softide Smart‐Bed prototype — an adjustable ("smart") bed combining electric actuators with non‐contact physiological sensing (Keeson Technology Corporation; developed 2020–2021; not a marketed device at the time of the study). Within‐patient randomised‐order crossover. Each participant underwent two whole‐night attended polysomnograms on the same study adjustable bed: (i) an observation night in the flat (0°) configuration (the within‐patient control), and (ii) an intervention night with the upper half of the bed raised to a fixed 30° for the whole night (adaptive/closed‐loop features disabled). The two nights were usually consecutive (median inter‐night gap 1 night). Night order was assigned 1:1 from a computer‐generated random sequence prepared centrally by the sponsor and disclosed to the site immediately before each participant's first study night. One centre (Qinhuangdao, n = 10) did not randomise (all observation‐first) and is handled by a pre‐specified sensitivity analysis. CONDITION: Obstructive sleep apnoea and habitual snoring ; Nervous System Diseases PRIMARY OUTCOME: Paired within‐patient change in total apnoea–hypopnoea index (AHI) measured using two whole‐night polysomnograms at intervention night and observation night Paired within‐patient change in whole‐night snoring burden (co‐primary) measured using two whole‐night acoustic recordings at intervention night and observation night SECONDARY OUTCOME: Paired within‐patient change in Oxygen Desaturation Inde X3% (ODI3) and Oxygen Desaturation Inde X4% (ODI4) measured using two whole‐night polysomnograms at intervention night and observation night Paired within‐patient change in oxygen‐desaturation morphology (duration/area/depth) measured using two whole‐night polysomnograms at intervention night and observation night Paired within‐patient change in positional behaviour, ?PHI = ?log2(supine/lateral minutes) measured using two whole‐night polysomnograms at intervention night and observation night Paired within‐patient change in positional physiology, ?PSI = ?log2(supine/lateral AHI), measured using two whole‐night polysomnograms at intervention night and observation night Paired within‐patient change in SpO2 summary statistics (mean/median/ variability) measured using two whole‐night polysomnograms at intervention night and observation night Safety measured using treatment‐emergent adverse events at on and after the intervention night INCLUSION CRITERIA: 1. Adults aged 18 years or older, male or female 2. Clinically suspected or polysomnography‐confirmed obstructive sleep apnoea (no minimum apnoea–hypopnoea inde X[AHI] required for enrolment) 3. Able to undergo two whole‐night polysomnograms on the study adjustable bed 4. Written informed consent