title: Increased alveolar nitric oxide concentration is related to nocturnal oxygen desaturation in obstructive sleep apnoea.
abstract: OBJECTIVE
  To assess distal/alveolar inflammation in patients with suggestive symptoms of obstructive sleep apnoea (OSA) using exhaled nitric oxide (NO) measured by two-compartment model (2-CM) after correction for axial NO back-diffusion (trumpet model).
  
  
  METHODS
  Ninety five patients suspected for OSA prospectively underwent pulmonary function test, overnight polysomnography (PSG), and exhaled NO measurement. Patients with apnoea-hypopnoea index (AHI) < 5/hour were included in non-OSA group. Exhaled NO was repeatedly measured after PSG in 21 OSA patients and 8 non-OSA subjects.
  
  
  RESULTS
  Alveolar NO concentration (C(ANO)) was significantly higher in OSA patients (n = 71; 4.07 ± 1.7 ppb) as compared with non-OSA subjects (n = 24; 2.24 ± 1.06 ppb; p < 0.0001) whilst maximal bronchial NO flux (J'awNO) and fractional exhaled NO (F(ENO)) did not differ between the two groups. C(ANO) was strongly associated to AHI (r = 0.701; p < 0.0001) and to recording time with SaO2 < 90% (ST-90%; r = 0.659; p < 0.0001) in OSA patients but not in non-OSA persons. The area under ROC curve for screening patients with OSA and significant nocturnal oxygen desaturation (ST-90% > 1%) was 0.865 ± 0.036 (95% IC, 0.793-0.937; p < 0.0001). C(ANO) at 4.5 ppb could detect these patients with specificity of 94% and sensitivity of 46%. Increase of C(ANO) measured after PSG was significantly related to oxygen desaturation index (ST-90%) in OSA patients.
  
  
  CONCLUSIONS
  Increased alveolar NO concentration was related to the severity of nocturnal oxygen desaturation in patients with OSA, linking the distal airway inflammation to intermittent hypoxia. (250 words).
authors: Department of Respiratory Physiology, Cochin Hospital, University Paris Descartes, Sorbonne Paris Cité, 27 rue du faubourg Saint-Jacques, 75679 Paris cedex 14, France.
authors: Thong
authors: T
authors: Hua-Huy
authors: Department of Pulmonology, St. Elisabeth Hospital, Namur, Belgium.
authors: Nhat-Nam
authors: NN
authors: Le-Dong
authors: Department of Respiratory Physiology, Cochin Hospital, University Paris Descartes, Sorbonne Paris Cité, 27 rue du faubourg Saint-Jacques, 75679 Paris cedex 14, France.
authors: Sy
authors: S
authors: Duong-Quy
authors: Department of Respiratory Physiology, Cochin Hospital, University Paris Descartes, Sorbonne Paris Cité, 27 rue du faubourg Saint-Jacques, 75679 Paris cedex 14, France.
authors: Laurent
authors: L
authors: Luchon
authors: Department of Respiratory Physiology, Cochin Hospital, University Paris Descartes, Sorbonne Paris Cité, 27 rue du faubourg Saint-Jacques, 75679 Paris cedex 14, France.
authors: Saïd
authors: S
authors: Rouhani
authors: Department of Respiratory Physiology, Cochin Hospital, University Paris Descartes, Sorbonne Paris Cité, 27 rue du faubourg Saint-Jacques, 75679 Paris cedex 14, France. Electronic address: anh-tuan.dinh-xuan@cch.aphp.fr.
authors: Anh Tuan
authors: AT
authors: Dinh-Xuan
mesh_terms: D000328:Adult; D000368:Aged; D001944:Breath Tests; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D006973:Hypertension; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000032:analysis*; D010100:Oxygen / Q000378:metabolism*; D017286:Polysomnography; D011446:Prospective Studies; D011650:Pulmonary Alveoli / Q000378:metabolism*; D020181:Sleep Apnea, Obstructive / Q000453:epidemiology / Q000378:metabolism* / Q000503:physiopathology
chemical_list: D009569:Nitric Oxide; D010100:Oxygen
keywords: Alveolar inflammation; Exhaled nitric oxide; Nocturnal oxygen desaturation; Obstructive sleep apnoea