Role of Parasympathetic Activity in Mild to Severe Asthma With Fixed Airway Obstruction (PARASMA Study)

Visit 1, After predosed spirometry is done, the patients will be received 4 puffs of salbutamol. 30 minutes later, if they meet the criteria of fixed airway obstruction based on ATS criteria, then they will continue to undergo serial spirometry at 1, 2, 3, and 4 hours. Then, the patients requested to be administered 4 puffs of ipratropium and do spirometry at 4.5 and 5 hours.

Visit 2, After predosed spirometry is done, the patients will be received 4 puffs of ipratropium they will continue to undergo serial spirometry at 30 minutes,1, 2, 3, and 4 hours. Then, the patients requested to be administered 4 puffs of salbutamol and do spirometry at 4.5 and 5 hours.

Visit 3, After predosed spirometry is done, the patients will be received 4 puffs of a placebo, and they will do spirometry at 30 minutes, 1 and 2 hours (Placebo arm). Then, the patients requested to be administered 4 puffs of ipratropium and 4 puffs of salbutamol and do spirometry at 4.5 and 5 hours (Salbutamol plus ipratropium arm)

Visit 3, After predosed spirometry is done, the patients will be received 4 puffs of a placebo, and they will do spirometry at 30 minutes, 1 and 2 hours (Placebo arm).