PHARYNGEAL CT STUDIES IN PATIENTS WITH MILD OR SEVERE UPPER AIRWAY-OBSTRUCTION DURING SLEEP

The upper airway cross-sectional areas were studied with pharyngeal co mputed tomography (CT) at the nasopharyngeal, velopharyngeal, tongue b ase and hyoid bone levels in 119 consecutively investigated patients w ith a snoring complaint. According to their findings in an all-night s tatic charge sensitive bed (SCSB) recording, the subjects were divided into four equally sized groups with increasing severity of nocturnal breathing disturbance. The body mass index (BMI) increased and the min imal cross-sectional area at the velopharyngeal level decreased consis tently as a function of the severity of nocturnal breathing disturbanc e. The minimal cross-sectional area at the hyoid bone level showed a b iphasic trend, with an initial decrease but a final increase, as the d egree of nocturnal breathing disturbance aggravated. The results contr adict the idea of gradually increasing anatomical narrowing of the upp er airways in general as the nocturnal breathing disturbance exacerbat es and support the concept of two anatomically determined entities of partial and complete upper airway obstruction during sleep.