Different patterns of exhaled nitric oxide response to β2-agonists in asthmatic patients according to the site of bronchodilation

JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY

卷:137

Article

Michils, Alain¹  Malinovschi, Andrei²  Haccuria, Amaryllis¹  Michiels, Sebastien¹  Van Muylem, Alain¹ 

[1] Univ Libre Bruxelles, Erasme Univ Hosp, Chest Dept, Brussels, Belgium

[2] Uppsala Univ, Dept Med Sci Clin Physiol, Uppsala, Sweden

关键词: Asthma;    fraction of exhaled nitric oxide;    bronchodilation;    ventilation distribution;   

DOI  :  10.1016/j.jaci.2015.09.054

来源: Elsevier

【 摘 要 】

Background: In asthmatic patients undergoing airway challenge, fraction of exhaled nitric oxide (FENO) levels decrease after bronchoconstriction. In contrast, model simulations have predicted both decreased and increased FENO levels after bronchodilation, depending on the site of airway obstruction relief. Objective: We sought to investigate whether beta(2)-agonists might induce divergent effects on FENO values in asthmatic patients as a result of airway obstruction relief occurring at different lung depths. Methods: FENO, FEV1, and the slope of phase III of the singlebreath washout test (S) of He (S-He) and sulfur hexafluoride (S-SF6) were measured in 68 asthmatic patients before and after salbutamol inhalation. S-He and S-SF6 decreases reflected preacinar and intra-acinar obstruction relief, respectively. Changes (Delta) were expressed as a percentage from the baseline. Results: No FENO change (vertical bar Delta FENO vertical bar <= 10%) was found in 16 patients (mean [SD]: 2.5% [5.2%]; ie, FENO5 group); a Delta FENO value of greater than 10% was found in 23 patients (31.7% [20.3%]; ie, the FENO+ group); and a Delta FENO value of less than -10% was found in 29 patients (-31.5% [17.3%]; ie, the FENO- group). All groups had similar Delta FEV1 values. In the FENO= group neither S-He nor S-SF6 changed, in the FENO+ group only SHe decreased significantly (-21.8% [SD 28.5%], P = .03), and in the FENO- group both SHe (-29.8% [24.0%], P < .001) and S-SF6 (-27.2% [23.3%], P < .001) decreased. Discussion: Three FENO behaviors were observed in response to beta(2)-agonists: a decrease likely caused by relief of an intra-acinar airway obstruction that we propose reflects amplification of nitric oxide back-diffusion, an increase likely associated with a predominant dilation up to the preacinar airways, and FENO stability when obstruction relief involved predominantly the central airways. In combination, these results suggest a new role for FENO in identifying the site of airway obstruction in asthmatic patients.

【 授权许可】

Free