We measured laryngeal resistance (Ria), upper airway resistance (Ruaw), and lower respiratory resistance below the larynx (Rirs) during methacholine and histamine provocation in 10 normal and 12 asthmatic subjects. In another 10 asthmatic subjects, Ria was measured during medication for spontaneous asthma attack. The Ria was measured with the low-frequency sound method. Direct measurements of Ruaw and Rirs were obtained using the 3-Hz forced oscillation technique with a needle inserted below the cricoid cartilage. In normal subjects, Ruaw increased in proportion to the increase in Rirs during methacholine and histamine provocation. In asthmatic subjects, control Ruaw was higher than the control Ruaw in normal subjects (p < 0.001) and Ruaw did not change despite an increase in Rirs during methacholine and histamine provocation. After medication for spontaneous asthma attack, Ria decreased in proportion to decrease in total respiratory resistance (Rrs). We conclude that in asthmatic subjects, Ria contributes to an increase in Rrs during both the nonspasmodic period and the spontaneous asthma attack but does not do so during bronchoprovocation, probably because the larynx is less sentsitive than the lower respiratory tract.
|Number of pages||8|
|Journal||American Review of Respiratory Disease|
|Publication status||Published - 1985|
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine