Study Design: A randomized, cross-over and double-blind study. Objective: To compare the pressure of 10 cmH2O and minimal effective pressure derived from manual titration on the effect of CPAP treatment in OSA. Methods: Patients with suspected OSA (age, body mass index and symptom) to be referred to a sleep centre were recruited. Patients with OSA confirmed by overnight full polysomnography (PSG) were invited to do standard overnight manual titration under PSG based on the Academy of Sleep Medicine (AASM) manual guidelines. Patients whose manual titration pressure lower than 10cmH2O and willing to participate in the study were invited to repeat two more nights (3th PSG and 4th PSG) under CPAP pressure at both 10cmH2O and the pressure derived from manual titration in random order. The sleep apnea-hypopnea index (AHI), obstructive sleep apnea index (OHI), arousal index (ArI), oxygen desaturation index (ODI), sleep structure, and treatment preference were to be observed.
Compliance of continuous positive airway pressure （CPAP） derived from auto-titration is similar to that derived from manual titration, although pressure derived from the former was usually 2-5 cmH2O higher than the latter. Therefore the Investigators hypothesize that accurate titration maybe not necessary for successful treatment of obstructive sleep apnea (OSA) as long as CPAP pressure was not lower than the minimal effective pressure.