An Investigation to Test the Efficacy of the High Flow (HF) Continuous Positive Airway Pressure (CPAP) in Patients With Obstructive Sleep Apnea (OSA)

Phase One: High Flow (HF) CPAP (HF-CPAP) Titration: Participants will attend the sleep lab to undergo a comprehensive split-night respiratory PSG. Each participant will be randomized to one of 20 L/min or 35 L/min of CPAP for the first half of the night and swapped to the alternate flow rate for the second half o the night. At the completion of night 3 participants will be categorized as responders or non-responders. Only responders will continue to Phase 2 of the investigation. Phase Two: HF-CPAP compared with CPAP: Participants will attend the sleep lab to undergo a comprehensive overnight respiratory PSG. Each participant will be randomized to HF-CPAP at a flow rate of 35 L/min or to conventional CPAP at their therapeutic pressure. They will spend the entire night on this treatment arm. Thew following night participants will undergo the alternative treatment arm for the duration of the night.