any of various drugs, as epinephrine or theophylline, that open bronchial air passages by relaxing the tightened muscles that surround the bronchial tubes, used to treat asthma, bronchitis, emphysema, etc.
However, people who have a cough with wheezing (bronchospasm), indicating that the bronchial airways are narrowed or blocked, may be given a bronchodilator to relax the muscles and increase ventilation.
The child then inhales a drug that widens the air passages (a short-acting bronchodilator) and the doctor takes another measurement of the lung capacity.
Sometimes when airways are obstructed, the patient is given a bronchodilator, and the test is performed again.
A vet might also decide to use aerosol therapy or a bronchodilator to help open the airways.