PT  - JOURNAL ARTICLE
AU  - Wheatley, JR
AU  - PD Pare
AU  - LA Engel
TI  - Reversibility of induced bronchoconstriction by deep inspiration in asthmatic and normal subjects
AID  - 10.1183/09031936.93.02040331
DP  - 1989 Apr 01
TA  - European Respiratory Journal
PG  - 331--339
VI  - 2
IP  - 4
4099  - http://erj.ersjournals.com/content/2/4/331.short
4100  - http://erj.ersjournals.com/content/2/4/331.full
SO  - Eur Respir J1989 Apr 01; 2
AB  - Five normal and five asthmatic subjects underwent a progressive methacholine provocation study. At each concentration inspiratory pulmonary resistance (RL) was measured, as well as isovolumic maximal flow and residual volume from both partial and complete forced expirations. Results were compared over the RL range of 6-11 cmH2O.1-1.S-1. The reversibility of bronchoconstriction by deep inspiration was quantified as the ratio of the flow increase to potential maximal increase; the reversibility of gas trapping was the ratio of decrease in residual volume to potential maximal decrease. The reversibility of bronchoconstriction did not differ between the groups. In contrast, the reversibility of gas trapping was smaller in asthmatic subjects (21 +/- 17%) than in normals (84 +/- 6%). As gas trapping reflects airway closure, our findings suggest that during induced bronchoconstriction airway closure is more resistant to the effects of deep inspiration in asthmatic than in normal subjects but the reversibility of bronchoconstriction by deep inspiration is not different.