The Effect of Acid Aerosols on Airway Responsiveness in Asthmatics

Abstract

ABSTRACT Most investigations have shown that short-term exposure to acid aerosols did not cause airway obstruction in normal subjects at concentrations up to 1 mg/m3, whereas some studies could demonstrate adverse effects in asthmatic subjects at concentrations of 0.1 mg/m3 or higher. Inhalation of acid aerosols may produce airway hyperreactivity to carbachol in normal subjects and may enhance airway hyperreactivity in asthmatic subjects. We investigated 12 patients with bronchial asthma inhaling aerosols of either saline (S), ammonium sulfate (AS), or sulfuric acid (SA). Two inhalations of 10 min were performed 30 min apart. Thirty minutes later, a hyperventilation challenge with 0.75 ppm SO2 was performed. We determined the ventilation rate necessary to increase SRaw by 100%, PV100SRaw, by stepwise increasing ventilation. The response showed large variation after AS and SA, with no significant differences between the first and the second inhalation. SRaw was significantly increased after AS. Mean PV100S...