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Bronchodilator responsiveness in normal infants and young children
A B Goldstein1, R G Castile, S D Davis
1Section of Pediatric Pulmonary Medicine, Children's Hospital, The Ohio State University College of Medicine, Columbus, Ohio 43205, USA.
Insights
Normal infants show airway narrowing reversible with bronchodilators. The youngest infants and those exposed to tobacco smoke had the greatest response to albuterol, indicating significant airway responsiveness.
Area of Science:
- Pediatric Pulmonology
- Respiratory Physiology
Background:
- Infants exhibit bronchoconstriction, reversible with beta-agonists.
- Limited data exists on baseline airway tone and bronchodilator response in infants.
- Keywords: airway responsiveness, asthma, tobacco smoke, infant pulmonary function, bronchodilator.
Purpose of the Study:
- To evaluate baseline airway responsiveness to inhaled albuterol in healthy infants.
- To assess changes in maximal expiratory flows as an indicator of airway response.
Main Methods:
- Maximal expiratory flow-volume curves were obtained from 41 healthy infants (5.4-141.4 weeks).
- Measurements were taken at baseline and 10 minutes post-inhalation of albuterol (n=28) or placebo (n=13).
- A metered-dose inhaler with a spacer was used for drug delivery.
Main Results:
- Albuterol significantly increased FEV(0.5), FEF(75%), and FEF(85%) compared to placebo (p < 0.05).
- Younger infants and those with maternal smoking exposure showed the greatest bronchodilator response.
- Six infants showed a significant increase in FEF(75%) exceeding two standard deviations from the placebo group mean.
Conclusions:
- Healthy infants possess baseline airway tone comparable to adults and older children.
- Infant airway responsiveness to bronchodilators is influenced by age and prenatal tobacco smoke exposure.
- Findings highlight the importance of considering these factors in infant respiratory health.
Unlabelled:
Several studies have demonstrated that normal infants exhibit bronchoconstriction after inhalation of nonspecific agonists and that the induced airway narrowing can be reversed by the inhalation of a beta-agonist. However, there are very limited data on baseline airway tone and the airway response to a beta-agonist in this subject population. The purpose of our study was to evaluate in normal infants baseline airway responsiveness to the inhaled beta-agonist, albuterol, using changes in maximal expiratory flows. Forty-one healthy infant volunteers with no history of respiratory disease or recurrent wheezing (ages 5.4 to 141.4 wk) were studied. Maximal expiratory flow- volume curves were obtained at baseline and 10 min after inhalation of albuterol (n = 28) or placebo (n = 13) using a metered-dose inhaler with a spacer. The mean percent change was significantly greater (p < 0.05) in the albuterol versus placebo group for FEV(0.5) (2.2% versus -1.5%), FEF(75%) (10.6% versus -3.1%), and FEF(85%) (12.9% versus 0.5%). Six of 28 albuterol-treated infants demonstrated increases in FEF(75%) greater than two standard deviations from the mean change in FEF(75%) seen in the placebo group. These infants were younger and more frequently exposed to maternal smoking during pregnancy. We conclude that normal healthy infants have overall levels of baseline airway tone that are similar to that reported in adults and older children; however, among the infants we evaluated the response to an inhaled bronchodilator was greatest in the youngest infants and in those exposed to tobacco smoking.
Keywords:
airway responsiveness; asthma; tobacco smoke; infant pulmonary function; bronchodilator