Short daytime ApneaGraph for initial case selection of obstructive sleep apnea–hypopnea syndrome before surgery

The aim of this study was to determine whether the 2-h daytime ApneaGraph (dAG) for patients with obstructive sleep apnea–hypopnea syndrome (OSAHS) can be used initially to diagnose and identify the site of obstruction before surgery. Fifty patients with OSAHS diagnosed by polysomnogram were enrolled in this prospective study. Sleep-related parameters, which include the indices for apnea–hypopnea (AHI), apnea index (AI), obstructive, central and mixed AHI (OAHI, CAHI and MAHI, respectively), the lowest oxygen saturation (LSaO₂) and the proportion of upper and lower airway obstruction (UPPER and LOWER, respectively), were measured by both daytime and nocturnal AG (nAG). Different operative techniques were used according to the obstruction site assessed by the nAG. Clinical outcomes were assessed with the Epworth Sleepiness Scale (ESS), visual analog scale (VAS), AI, AHI and LSaO₂. All the indices except LSaO₂ found no significant differences between dAG and nAG; there were significant positive correlations with regard to most indices, but not for CAHI between dAG and nAG. When compared dAG with nAG, most moderate and severe patients had predominant sites of obstructions in the upper level. Postoperative ESS, VAS, AI and AHI decreased significantly, while LSaO₂ significantly increased compared with those preoperative counterparts. dAG may be used as an alternative means for early and low-cost diagnostic evaluation of OSAHS before surgery.