title: Exhaled and sputum nitric oxide in bronchiectasis: correlation with clinical parameters.
abstract: OBJECTIVE
  Although there has been tremendous attention on endogenous nitric oxide (NO) production in many respiratory and systemic diseases, little is known on NO production in bronchiectasis.
  
  
  METHODS
  We determined exhaled and sputum NO levels in 109 patients with stable bronchiectasis (71 women; mean +/- SD age, 58.2 +/- 14.1 years) and 78 control subjects (39 women; mean age, 56.7 +/- 12.1 years) by using an automatic chemiluminescence analyzer.
  
  
  RESULTS
  There was no significant difference in exhaled NO between patients with bronchiectasis and control subjects (p = 0.11). Bronchiectasis patients with Pseudomonas aeruginosa infection had a significantly lower exhaled, but not sputum, NO levels than their counterparts and control subjects (p = 0.04 and p = 0.009, respectively). Exhaled NO correlated with 24-h sputum volume in P aeruginosa-infected patients (r = - 0.36; p = 0.002). After adjustment for sputum volume and number of bronchiectatic lung lobes, P aeruginosa-infected patients still had lower exhaled NO levels than their counterparts (p = 0.01). There was no correlation between exhaled NO with FEV(1), FVC, and the number of bronchiectatic lung lobes (p > 0.05). Sputum NO levels were not different between patients and control subjects (p = 0.64), and had no correlation with clinical parameters.
  
  
  CONCLUSIONS
  Exhaled NO appears to be reduced among bronchiectasis patients with P aeruginosa infection independent of other clinical parameters, and further studies on the potential mechanisms and pathogenetic implications of this reduction should be pursued.
authors.affiliation: Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong SAR, China. kwttsang@hkucc.hku.hk
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Tsang
authors.forename: Raymond
authors.initials: R
authors.lastname: Leung
authors.forename: Peter Chin-Wan
authors.initials: PC
authors.lastname: Fung
authors.forename: Shelley L
authors.initials: SL
authors.lastname: Chan
authors.forename: George L
authors.initials: GL
authors.lastname: Tipoe
authors.forename: Gaik C
authors.initials: GC
authors.lastname: Ooi
authors.forename: Wah K
authors.initials: WK
authors.lastname: Lam
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001944:Breath Tests; D001987:Bronchiectasis / Q000175:diagnosis*; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000032:analysis*; D018410:Pneumonia, Bacterial / Q000175:diagnosis; D011379:Prognosis; D011552:Pseudomonas Infections / Q000175:diagnosis; D011550:Pseudomonas aeruginosa; D013183:Sputum / Q000737:chemistry*; D014797:Vital Capacity / Q000502:physiology
chemical_list: D009569:Nitric Oxide