title: Bronchial responsiveness during esophageal acid infusion.
abstract: Among the possible mechanisms explaining the worsening of asthma due to gastroesophageal reflux disease (GERD) is the increase in bronchial hyperresponsiveness. The effects of GERD on bronchial hyperresponsiveness in patients with bronchial asthma have yet to be studied in significant detail. The aim of this study was to determine the effects of esophageal acid perfusion on bronchial responsiveness to bradykinin in patients with both asthma and GERD. In 20 patients with asthma and GERD disease, esophageal pH was monitored with a pH meter and bronchial responsiveness was evaluated by aerosol inhalation of bradykinin during esophageal acid perfusion and, 24 h earlier or later the patients were submitted to another bronchial provocation test without acid infusion. No significant changes were observed in FEV(1), FEF(25-75%), FVC, or PEF during acid perfusion. The response to the bronchial provocation test did not differ between the control day and the day of acid infusion (p = 0.61). The concentration provoking a 20% fall in FEV(1) (geometric mean +/- geometric SD) was 1.09 +/- 5.84 on the day of acid infusion and 0.98 +/- 5.52 on the control day. There is no evidence that acid infusion changes bronchial responsiveness to bradykinin. These findings strongly question the significance of acid infusion as a model to study the pathogenesis of GERD-induced asthma.
authors.affiliation: Pulmonary Division, Department of Medicine, University of São Paulo Medical School at Ribeirão Preto, Ribeirão Preto, SP 14048-900, Brazil.
authors.forename: Ana Carla S
authors.initials: AC
authors.lastname: Araujo
authors.forename: Lílian Rose O
authors.initials: LR
authors.lastname: Aprile
authors.forename: Roberto O
authors.initials: RO
authors.lastname: Dantas
authors.forename: João
authors.initials: J
authors.lastname: Terra-Filho
authors.forename: Elcio O
authors.initials: EO
authors.lastname: Vianna
mesh_terms: D000328:Adult; D001249:Asthma / Q000209:etiology / Q000503:physiopathology*; D001920:Bradykinin / Q000494:pharmacology; D001980:Bronchi / Q000187:drug effects / Q000503:physiopathology*; D004305:Dose-Response Relationship, Drug; D004947:Esophagus / Q000503:physiopathology*; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D005764:Gastroesophageal Reflux / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D006851:Hydrochloric Acid / Q000009:adverse effects / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012130:Respiratory Hypersensitivity / Q000139:chemically induced / Q000503:physiopathology; D016037:Single-Blind Method; D013147:Spirometry; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D014665:Vasodilator Agents; D006851:Hydrochloric Acid; D001920:Bradykinin