title: [An analysis of pharyngeal respiratory pressure before and after onset of obstruction in respiratory obstructive sleep apnea hypopnea syndrome].
abstract: OBJECTIVE
  To study the characteristics of pharyngeal respiratory pressure before and after onset of airflow obstruction events in obstructive sleep apnea hypopnea syndrome (OSAHS).
  
  
  METHODS
  The respiratory pressure in nasopharynx, oropharynx, and hypopharynx in 8 patients with OSAHS and 9 normal persons were evaluated through catheter manometer. Base on mean respiratory pressure and the ratio of negative respiratory pressure persistent time, the characteristics of pharyngeal respiratory pressure before and after the event onset were analyzed.
  
  
  RESULTS
  During sleep, the pharyngeal respiratory pressure in normal persons had similar and periodical wave shape. The ratio of negative respiratory pressure persistent time was less than 0.5. In patients with OSAHS, when the obstruction of airflow happened, the pharyngeal respiratory pressure fluctuated violently, the wave shape became irregular, and the negative expiratory pressure was evident. The mean respiratory pressure was 1 to 2 order of magnitude larger than in normal persons, even reaching -990 Pa. The ratio of persistent negative pressure time was larger than normal. During the intermittent period, the wave shape of pharyngeal respiratory pressure was regular and periodical, the pressure wave shape was different from onset of obstruction. However, in the intermittent period, the mean respiratory pressure, the ratio of negative respiratory pressure persistent time, and other characteristics were still statistically different from normal persons (P < 0.05).
  
  
  CONCLUSIONS
  During the intermittent period, the pharyngeal respiratory pressure in patients with OSAHS during sleep is basically different from the pharyngeal respiratory pressure in normal person. The characteristics of pharyngeal respiratory pressure in intermittent period indicates that both structural and functional abnormalities in pharyngeal cavity in patients with OSAHS, which affect the respiratory airflow during sleep are inherent. The effects are more prominent during onset period, suggesting that the characteristics of the pharyngeal pressure of breathing during the onset period will be more important to the mechanism of airflow obstruction.
authors.affiliation: Department of Otorhinolaryngology, The 359th Hospital of PLA, Zhenjiang, Jiangsu Province 212001, China. liuyongyi888888@sohu.com
authors.forename: Yong-yi
authors.initials: YY
authors.lastname: Liu
authors.forename: Ya-jun
authors.initials: YJ
authors.lastname: Bao
authors.forename: Wen-hua
authors.initials: WH
authors.lastname: Liu
authors.forename: Da-kang
authors.initials: DK
authors.lastname: Yao
authors.forename: Kai-rong
authors.initials: KR
authors.lastname: Qin
authors.forename: Lin-hui
authors.initials: LH
authors.lastname: Jiang
authors.forename: Chen
authors.initials: C
authors.lastname: Sang
mesh_terms: D000328:Adult; D000403:Airway Resistance; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D010614:Pharynx / Q000503:physiopathology*; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology*