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 尾2-agonist but not maintenance oral corticosteroid.
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鈥?sub>awNO [nL/s]), and peripheral small airway/alveolar NO concentration (CANO [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.
Group 1 included 17 patients (6 men) with asthma, age 52 卤 12 years, studied at baseline, during 18 exacerbations with abnormal Feno at 50 mL/s, J鈥?sub>awNO, and/or CANO, and post 8- to 10-day tapering 40 mg prednisone (recovery). Baseline: IgE, 332 卤 243 K渭; total blood eosinophils, 304 卤 266 cells/渭L; body mass index, 28 卤 6; ACT, 16 to 19; and FEV1, 2.5 卤 0.7 L (86%卤 20%predicted); exacerbation: FEV1, 1.7 卤 0.4 L (60%卤 17%) (P聽< .001); recovery: FEV1, 2.5 卤 0.7 L (85%卤 13%) (P聽< .001). Group 2 included 11 (7 men) similarly treated patients with asthma, age 49 卤 14 years, studied at baseline, during 15 exacerbations with normal Feno at 50 mL/s, J鈥?sub>awNO, and CANO. Baseline: IgE, 307 卤 133 K渭; total blood eosinophils, 296 卤 149 cells/渭L; body mass index, 28 卤 6; ACT, 16 to 19; and FEV1, 2.7 卤 0.9 L (71%卤 12%predicted); exacerbation: FEV1, 1.7 卤 0.6 L (54%卤 19%) (P聽< .006); recovery: FEV1, 2.7 卤 0.9 L (70%卤 14%) (P聽= .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 (鈮?006) decrease from baseline in FEV1 (L) during exacerbation and similar increase (鈮?006) at recovery.
Increased versus normal exhaled NO during outpatient exacerbation in patients with moderate-to-severe asthma on inhaled corticosteroid and long-acting 尾2-agonist but not maintenance oral corticosteroid does not preclude a robust clinical and spirometric response to tapering oral prednisone.