Modified Adaptive Servoventilation (ASV) Compared to Conventional ASV

Adaptive servoventilation (ASV) is a type of non-invasive ventilation which ameliorates central sleep and/or mixed apnea and periodic breathing. Previous studies in the field have shown that treatment of periodic breathing with ASV improves sleep quality and quality of life. In reducing central apneas, ASV reduces overall arousal index, and increases overall slow wave sleep and rapid eye movement (REM) sleep more than oxygen, continuous positive airway pressure or bi-level treatments. ASV can also more effectively reduce central apnea and overall apnea/hypopnea index (AHI) in patients on long-term opiates, and appears to effectively treat Complex Sleep Apnea Syndrome. It is more effective than other forms of non-invasive ventilation for patients with central and/or mixed apnea or periodic breathing, and is better tolerated. This is a prospective, randomised, crossover, observational study. Subjects will spend one night on conventional ASV and one night on modified ASV with full in-lab polysomnography (PSG) during therapy on both nights. Objective and subjective parameters will be recorded and analysed.