PHARYNGEAL AIR-FLOW DURING SLEEP

This study was conducted to investigate the effects of sleep and nasal resistance on pharyngeal airflow in a group of healthy male adults wi thout complaint of habitual snoring. Twelve subjects aged 21 to 60 yea rs were studied in a sleep laboratory during exclusive nasal breathing . Nasal and pharyngeal airflow variables were measured concomitantly a t different stages of sleep. Awake pharyngeal resistance averaged 0.02 -0.03 Pa/cm(3)/s in recumbency. In stage 2 sleep and quiet breathing r esistance increased by a factor of 3-4 and by a factor of 7-8 during s noring. Increased nasal loading did not increase pharyngeal resistance further or induce snoring. Mostly, increased pharyngeal resistances w ere of similar magnitude in both phases of respiration, but in a few i nstances inspiratory resistance exceeded that in expiration, and in a similar number the reverse was found. Overall, compliance of the phary ngeal airway was not a prominent feature in this group of subjects. Th e relationship between transpharyngeal pressure and resistance should be studied further in order to simplify future studies of airflow duri ng sleep.