Effect on spirometry of distilled water and cromoglycate solutions nebulised by a small portable ultrasonic nebuliser

The airway response to inhaled ultrasonically nebulised distilled water and three disodium cromoglycate solutions (DSCG in distilled water, normal saline and buffered saline) produced by a small portable nebuliser was determined by spirometry in 12 stable adult asthmatics in a double-blind trial. The mean percentage falls in forced expiratory volume in 1s (FEV1) were 13.4% following distilled water, 5.6% following DSCG in distilled water, 4.8% following DSCG in normal saline, 6.9% after DSCG in buffered saline. The fall in FEV1 was significantly greater (p less than 0.01) after distilled water than after all DSCG solutions with no significant difference between the DSCG solutions. Coughing was also greater during inhalation of nebulised distilled water than during inhalation of nebulised DSCG solutions (p less than 0.01).