Abstract
Bronchomotor tone after deep inspiration and bronchial responsiveness to methacholine were studied at 4:00 A.M. and 4:00 P.M. in 14 normal and 13 asthmatic subjects. Bronchomotor tone was assessed with respiratory resistance (Rrs) measured by the forced oscillation method. Bronchial responsiveness to methacholine and baseline Rrs were higher at 4:00 A.M. than at 4:00 P.M. in both normal and asthmatic subjects (p < 0.01). The difference in methacholine threshold between 4:00 P.M. and 4:00 A.M. in asthmatics was similar to that in normal subjects. Immediately after deep inspiration, Rrs decreased more at 4:00 A.M. than at 4:00 P.M. in normal subjects. In contrast, asthmatic subjects showed a significantly greater immediate increase in Rrs after deep inspiration at 4:00 A.M. than at 4:00 P.M. It is suggested that the bronchoconstrictive effect after deep inspiration is a distinguishing characteristic of asthmatics.
Original language | English |
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Pages (from-to) | 278-282 |
Number of pages | 5 |
Journal | American Review of Respiratory Disease |
Volume | 132 |
Issue number | 2 |
Publication status | Published - 1985 |
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine