Bronchiolitis is an acute, highly contagious, viral infection of the lungs that is common in infants. It causes the small airways in the lungs to become inflamed, blocking the free passage of air so that the infant becomes breathless, wheezy and short of oxygen. Bronchodilators are drugs often used as aerosols to widen the air passages by relaxing the bronchial muscle. They are effective in helping infants and adults with asthma. Howver, unlike asthmatics, infants with bronchiolitis are usually wheezing for the first time and wheezing for a different reason, that is to say, because their airways are clogged with debris. Therefore, infants with bronchiolitis may be less likely to respond to bronchodilators.
This review of trials found no effect of bronchodilators on oxygen saturation. Some infants treated as outpatients showed a short-term improvement in respiratory scores, but infants hospitalized for bronchiolitis showed no significant benefit of bronchodilator treatment. This review also found that bronchodilators do not reduce the need for hospitalization, do not shorten the length of stay in hospital or shorten illness duration at home. Side effects of bronchodilators include rapid heart beat and shakiness. Given these side effects and little evidence that they are effective, bronchodilators are not helpful in the management of bronchiolitis.
This review is limited by the small number of studies that use the same outcomes. The small number of infants included in each of these studies limits the ability to show statistically important differences between bronchodilator and placebo treatment. This review is also limited by the use of clinical scores that may vary from one observer to the next. Also older studies included children who had wheezed before and may have asthma.