Indices from flow-volume curves in relation to cephalometric, ENT- and sleep-O2 saturation variables in snorers with and without obstructive sleep-apnoea

In a group of 37 heavy snorers with obstructive sleep apnoea (OSA, Group 1) and a group of 23 heavy snorers without OSA (Group 2) cephalometric indices, ENT indices related to upper airway collapsibility, and nocturnal O2 desaturation indices were related to variables from maximal expiratory and inspiratory flow-volume (MEFV and MIFV) curves. The cephalometric indices used were the length and diameter of the soft palate (spl and spd), the shortest distance between the mandibular plane and the hyoid bone (mph) and the posterior airway space (pas). Collapsibility of the upper airways was observed at the level of the tongue base and soft palate by fibroscopy during a Muller manoeuvre (mtb and msp) and ranked on a five point scale. Sleep indices measured were the mean number of oxygen desaturations of more than 3% per hour preceded by an apnoea or hypopnoea of more than 10 s (desaturation index), maximal sleep oxygen desaturation, baseline arterial oxygen saturation (Sa,O2) and, in the OSA group, percentage of sleep time with Sa,O2