title: In moderate-to-severe asthma patients monitoring exhaled nitric oxide during exacerbation is not a good predictor of spirometric response to oral corticosteroid.
abstract: BACKGROUND
  The importance of monitoring exhaled nitric oxide (NO) in asthma remains controversial.
  
  
  OBJECTIVE
  To measure exhaled NO, postnebulized albuterol/ipratropium spirometry, and Asthma Control Test (ACT) during asthma exacerbation requiring 8- to 10-day tapering oral corticosteroid in nonsmoking patients with moderate-to-severe asthma on moderate-dose inhaled corticosteroid and long-acting β(2)-agonist but not maintenance oral corticosteroid.
  
  
  METHODS
  After measuring the fraction of exhaled NO (Feno [ppb]) at 50, 100, 150, and 200 mL/s, the total Feno at 50 mL/s (ppb), large central airway NO flux (J'(awNO) [nL/s]), and peripheral small airway/alveolar NO concentration (C(ANO) [ppb]) were calculated and corrected for NO axial back-diffusion. Outpatient exacerbation required the patient with asthma to be afebrile with normal chest x-ray and white blood cell count.
  
  
  RESULTS
  Group 1 included 17 patients (6 men) with asthma, age 52 ± 12 years, studied at baseline, during 18 exacerbations with abnormal Feno at 50 mL/s, J'(awNO), and/or C(ANO), and post 8- to 10-day tapering 40 mg prednisone (recovery). Baseline: IgE, 332 ± 243 Kμ; total blood eosinophils, 304 ± 266 cells/μL; body mass index, 28 ± 6; ACT, 16 to 19; and FEV(1), 2.5 ± 0.7 L (86% ± 20% predicted); exacerbation: FEV(1), 1.7 ± 0.4 L (60% ± 17%) (P < .001); recovery: FEV(1), 2.5 ± 0.7 L (85% ± 13%) (P < .001). Group 2 included 11 (7 men) similarly treated patients with asthma, age 49 ± 14 years, studied at baseline, during 15 exacerbations with normal Feno at 50 mL/s, J'(awNO), and C(ANO). Baseline: IgE, 307 ± 133 Kμ; total blood eosinophils, 296 ± 149 cells/μL; body mass index, 28 ± 6; ACT, 16 to 19; and FEV(1), 2.7 ± 0.9 L (71% ± 12% predicted); exacerbation: FEV(1), 1.7 ± 0.6 L (54% ± 19%) (P< .006); recovery: FEV(1), 2.7 ± 0.9 L (70% ± 14%) (P= .002). On comparing group 1 versus group 2, there was no significant difference for baseline IgE, eosinophils, body mass index, and ACT and similar significant (≤.006) decrease from baseline in FEV(1) (L) during exacerbation and similar increase (≤.006) at recovery.
  
  
  CONCLUSIONS
  Increased versus normal exhaled NO during outpatient exacerbation in patients with moderate-to-severe asthma on inhaled corticosteroid and long-acting β(2)-agonist but not maintenance oral corticosteroid does not preclude a robust clinical and spirometric response to tapering oral prednisone.
authors.affiliation: Department of Medicine, Pulmonary Division, Lakewood Regional Medical Center, Lakewood, CA 90712, USA. afgelb@msn.com
authors.forename: Arthur F
authors.initials: AF
authors.lastname: Gelb
authors.forename: Roxanna
authors.initials: R
authors.lastname: Moridzadeh
authors.forename: Deepak H
authors.initials: DH
authors.lastname: Singh
authors.forename: Christine
authors.initials: C
authors.lastname: Fraser
authors.forename: Steven C
authors.initials: SC
authors.lastname: George
mesh_terms: D000284:Administration, Oral; D000305:Adrenal Cortex Hormones / Q000008:administration & dosage / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D001249:Asthma / Q000175:diagnosis* / Q000188:drug therapy*; D018450:Disease Progression; D045853:Exhalation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000032:analysis*; D011379:Prognosis; D012129:Respiratory Function Tests; D013147:Spirometry; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D000305:Adrenal Cortex Hormones; D009569:Nitric Oxide