Maximal degree of airway narrowing induced by methacholine and adenosine monophosphate: relationship with the decrease in forced vital capacity

• Published in: Annals of allergy, asthma, & immunology Vol. 105; no. 6; pp. 418 - 424
• Main Authors: Prieto, Luis, MD, PhD, Lopez, Victoria, MD, Perez-Frances, Carmen, MD, PhD, Marin, Julio, MD, PhD
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01-12-2010; Elsevier
• Subjects: Adenosine Monophosphate; Adult; Allergy and Immunology; Asthma - diagnosis; Asthma - etiology; Asthma - physiopathology; Biological and medical sciences; Bronchial Hyperreactivity - chemically induced; Bronchial Provocation Tests - methods; Bronchoconstriction - drug effects; Bronchoconstrictor Agents; Dermatology; Female; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Humans; Male; Medical sciences; Methacholine Chloride; Middle Aged; Pollen - adverse effects; Rhinitis, Allergic, Perennial - diagnosis; Rhinitis, Allergic, Perennial - etiology; Sarcoidosis. Granulomatous diseases of unproved etiology. Connective tissue diseases. Elastic tissue diseases. Vasculitis; Vital Capacity; Respiratory tract; Immunopathology; Immunology; AMP; Dermatology; Forced vital capacity; Narrowing; Respiratory system
• ISSN: 1081-1206; 1534-4436
• DOI: 10.1016/j.anai.2010.10.002

Background Changes in forced vital capacity (FVC) may represent an indirect method for the detection of plateau in response to inhaled bronchoconstrictor agents. Objective To determine the relationship between the level of plateau obtained with either methacholine or adenosine monophosphate (AMP) and the decrease in FVC induced by each bronchoconstrictor agent. Methods Airway responsiveness to high concentrations of methacholine and AMP was determined in patients with intermittent asthma (n = 41) or allergic rhinitis (n = 26). Furthermore, allergen-induced changes in the response to each bronchoconstrictor agent were investigated in 18 pollen-sensitive patients. Concentration-response curves were characterized by the slope of the FVC values recorded at each step of the challenge against the corresponding forced expiratory volume in 1 second (FEV1) values and, if possible, by the level of plateau. Results The slope FVC vs FEV1 was similar in patients with plateau and in those without plateau. In patients with pollen allergy, the mean (95% confidence interval) for the level of plateau detected with methacholine increased from 16.8% (11.8%–22.0%) before the pollen season to 21.7% (14.8%–28.6%, P = .008) during the pollen season, whereas pollen-induced changes in the slope FVC vs FEV1 were not significant. Similar results were obtained with AMP. Conclusions In patients with allergic rhinitis or intermittent asthma, methacholine or AMP-induced changes in FVC are not significantly related to the presence or level of plateau. Furthermore, these 2 constituents of the concentration-response curve can be modified independently by a proinflammatory stimulus. These results suggest that the bronchoconstrictor-induced change in FVC cannot be used as a surrogate estimation of the level of plateau.