title: Study of Exhaled Nitric Oxide in Subjects with Suspected Obstructive Sleep Apnea: A Pilot Study in Vietnam.
abstract: OBJECTIVE
  The concentration of exhaled nitric oxide (eNO), reflecting the activity of inducible NO synthase in airway epithelium, has been found to increase in patients with obstructive sleep apnea (OSA). This study aimed to measure eNO concentration in patients with suspected OSA and to correlate different eNO parameters with clinical and sleep apnea characteristics.
  
  
  METHODS
  In this cross-sectional study, all patients underwent in-lab overnight polysomnography (PSG) and eNO measurement using a method of multiple flow rates before and after PSG (pre- and post-PSG).
  
  
  RESULTS
  According to the result of PSG, 82 persons were divided into two groups: control subjects (n = 30; 54 ± 14 years) and patients with OSA defined as apnea-hypopnea index (AHI) ≥ 5/hour (n = 52; 53 ± 12 years). Body mass index (BMI) and neck and abdomen circumferences of OSA patients were significantly higher than those from control subjects. In OSA group, post-PSG alveolar NO concentration (CANO) (5.3 ± 1.9 ppb) was significantly higher than pre-PSG CANO (4.0 ± 1.7 ppb; P < 0.001). Significant correlations have been found between CANO and AHI (P < 0.001) and between CANO and nadir SpO2 (P < 0.05). The daytime CANO value of more than 4.1 ppb can be used to screen symptomatic subjects for the presence of OSA with a high specificity of 93.3%.
  
  
  CONCLUSIONS
  Our findings indicate CANO as a surrogate marker for OSA in persons with suggestive symptoms.
authors.affiliation: Bio-Medical Research Center, Lam Dong Medical College, Dalat, Lam Dong 063, Vietnam; Department of Respiratory Physiology, Cochin Hospital, Paris Descartes University, Sorbonne Paris Cité, 75014 Paris, France.
authors.forename: Sy
authors.initials: S
authors.lastname: Duong-Quy
authors.affiliation: Department of Respiratory Physiology, Cochin Hospital, Paris Descartes University, Sorbonne Paris Cité, 75014 Paris, France.
authors.forename: Thong
authors.initials: T
authors.lastname: Hua-Huy
authors.affiliation: Department of Technology and Biology, Dalat, Lam Dong 063, Vietnam.
authors.forename: Huyen-Tran
authors.initials: HT
authors.lastname: Tran-Mai-Thi
authors.affiliation: Department of Pulmonology, St. Elisabeth Hospital, 5000-5999 Namur, Belgium.
authors.forename: Nhat-Nam
authors.initials: NN
authors.lastname: Le-Dong
authors.affiliation: Pennsylvania State University, 500 University Drive, Hershey, PA 17033, USA.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Craig
authors.affiliation: Department of Respiratory Physiology, Cochin Hospital, Paris Descartes University, Sorbonne Paris Cité, 75014 Paris, France.
authors.forename: Anh-Tuan
authors.initials: AT
authors.lastname: Dinh-Xuan
mesh_terms: D015992:Body Mass Index; D001944:Breath Tests; D003430:Cross-Sectional Studies; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010865:Pilot Projects; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis*; D012913:Snoring / Q000209:etiology; D014744:Vietnam; D014797:Vital Capacity / Q000502:physiology
chemical_list: D009569:Nitric Oxide; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III