Effect of intraesophageal acid instillation on airway reactivity in patients with asthma.

OBJECTIVE

To study the change in airway reactivity due to presence of acid in lower esophagus and its reversibility by antacid.

METHOD

In this double blind study 12 subjects with asthma and gastroesophageal reflux received acid (N/10 hydrochloric acid) and antacid (mixture of magnesium trisilicate and aluminum hydroxide) perfusion in lower esophagus via a nasogastric tube. The four combinations were antacid-antacid (control), antacid-acid, acid-antacid and acid-acid. Airway reactivity (Histamine PD20) was recorded after each perfusion.

RESULTS

Histamine PD20 significantly decreased (airway reactivity increased) (p < 0.05) with all three combinations containing acid as compared to control. No significant difference in airway reactivity was observed if the antacid was given before or after the acid.

CONCLUSION

Presence of acid in lower esophagus can increase airway reactivity. This effect lasts longer than the presence of acid in esophagus itself.