Six intervention trials (n=107) were included in the wider review and are reported below. One trial was a randomised single-blind crossover trial (n=13).
The author reported that study quality was largely poor, with no power calculations, a lack of definitions for apnoea, hypopnoea and OSA, and poor reporting in general.
One trial (n=13) involving obese, male, moderate-to-severe OSA patients showed an 80% reduction in A and HI in more obese hypoxaemic patients who slept in an upright position at 60°. The remaining five trials (n=94) used a variety of methods to avoid a supine sleeping position and found that, on the whole, side lying was an effective method in improving the severity of SAS. The randomised crossover trial (n=13) showed significant reductions in A and HI, as well as improvements in oxygen saturation with CPAP and positioning, although the difference favoured CPAP.