Response to the inhaled bronchodilator, metaproterenol, was evaluated in 28 outpatient infants and young children with cystic fibrosis (CF) (mean age, 16 months) and in 22 normal control children (mean age, 13 months). Lung function was assessed from partial expiratory flow volume curves generated by the rapid compression techniques and was quantitated by the maximal expiratory flow at functional residual capacity (V̇maxFRC). For the normal control group there was no significant change in V̇maxFRC after the aerosol of either normal saline or metaproterenol. At baseline, the group of infants with CF had significantly lower values of V̇maxFRC than did the normal control infants (202 versus 273 ml/s, p<0.05). The CF group demonstrated no significant change from baseline V̇maxFRC after the aerosol of normal saline. However, after metaproterenol the CF group had a significant increase (p<0.001) in V̇maxFRC, which eliminated the difference in V̇maxFRC between the CF and normal control groups (267 versus 276 ml/s). We conclude that infants and young children with CF have increased bronchomotor tone and that bronchoconstriction represents a significant component of the airway obstruction present in patients with CF at this age.
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine