Continuous pressure measurements during sleep to localize obstructions in the upper airways in heavy snorers and patients with obstructive sleep apnea syndrome.

Twenty-one patients were examined, of whom 18 suffered from obstructive sleep apnea syndrome and 3 were heavy snorers. The diagnosis was established by a combination of medical history, clinical examination and standard nocturnal polysomnography. Five pressure transducers were used in the pharynx and one in the esophagus, in addition to monitors for oxygen saturation and oro-nasal airflow. A clinically significant obstruction was defined as occurring when the pressure difference between two transducers was higher than 50% of the more caudal of the two pressures. In the 20 patients having obstructions during sleep, 7 had obstruction in only one segment of the airway, 9 in two segments and 4 in three segments. All but 2 patients had obstructions in the velopharyngeal region. Since the effect of uvulopalatopharyngoplasty (UPPP) is best during the first few months after surgery, 10 patients were re-examined after only 3 months in order to record optimal results sequentially. Of these, 6 still had obstructions involving the velopalatine segments and only 4 had none. This may explain why UPPP has a success rate of only 50-70% in most publications, depending on the definitions of success.