Effects of esophageal acid perfusion on cough responsiveness in patients with bronchial asthma.
OBJECTIVE
The effect of gastroesophageal reflux (GER) on cough responsiveness in patients with bronchial asthma has yet to be studied in significant detail. The purpose of this study was to assess the effect of distal esophageal acid perfusion on cough responsiveness in patients with bronchial asthma.


METHODS
In seven patients with mild persistent bronchial asthma (mean +/- SD age, 57.7 +/- 3.7 years; four women and three men), esophageal pH was monitored by a pH meter and cough responsiveness was evaluated by single-breath aerosol inhalation of capsaicin with increasing dosage from 0.30 to 9.84 nmol. Simultaneously, esophageal perfusion was performed through an esophageal tube filled with either saline solution or 0.1 N hydrochloric acid (HCl), the order of which was selected at random, in 1-week intervals. Results were expressed as the lowest concentration of capsaicin eliciting three coughs (PD3). Spirometry was also performed during esophageal pH monitoring.


RESULTS
A significant decrease in the geometric mean of log PD3 was observed during distal esophageal HCl perfusion (0.45 +/- 0.04 nmol) compared with that of the saline solution perfusion (0.04 +/- 0.06 nmol) [p < 0.01]. However, no significant changes were observed either in FVC, FEV1, or peak expiratory flow during the periods of the saline solution or HCl perfusion.


CONCLUSIONS
The present data demonstrate that an increase in cough responsiveness may be induced when HCl stimulates the distal portion of esophagus in patients with bronchial asthma, suggesting that the GER would be one of the important factors that influence asthmatic status.
Wu
De-Nan
DN
Third Department of Internal Medicine, Iwate Medical University, School of Medicine, Morioka, Japan.
Yamauchi
Kohei
K
Kobayashi
Hitoshi
H
Tanifuji
Yukio
Y
Kato
Chieko
C
Suzuki
Kazuyuki
K
Inoue
Hiroshi
H
D000336:Aerosols; D001249:Asthma / Q000503:physiopathology*; D002211:Capsaicin; D003371:Cough / Q000503:physiopathology*; D005260:Female; D005764:Gastroesophageal Reflux / Q000503:physiopathology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D013147:Spirometry
D000336:Aerosols; D002211:Capsaicin