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Bronchodilator responsiveness in infants and young children with cystic fibrosis
1Department of Pediatrics, James Whitcomb Riley Hospital for Children, Indiana University School of Medicine, Indianapolis 46223.
Insights
Infants and young children with cystic fibrosis (CF) exhibit increased bronchomotor tone. Bronchodilator response to metaproterenol significantly improved airway obstruction in young CF patients.
Area of Science:
- Pediatric Pulmonology
- Respiratory Medicine
- Cystic Fibrosis Research
Background:
- Cystic Fibrosis (CF) is a genetic disorder affecting multiple organs, primarily the lungs.
- Airway obstruction is a hallmark of CF, but its components in early childhood are not fully understood.
- Infants and young children with CF often present with respiratory symptoms requiring evaluation.
Purpose of the Study:
- To assess the response to an inhaled bronchodilator, metaproterenol, in infants and young children with CF.
- To determine if bronchoconstriction contributes to airway obstruction in this age group.
- To compare lung function parameters between CF patients and healthy controls.
Main Methods:
- Evaluated 28 infants and young children with CF and 22 healthy controls (mean ages 16 and 13 months, respectively).
- Assessed lung function using partial expiratory flow-volume curves and maximal expiratory flow at functional residual capacity (VmaxFRC).
- Administered aerosols of normal saline and metaproterenol to measure changes in VmaxFRC.
Main Results:
- Baseline VmaxFRC was significantly lower in CF patients compared to controls (202 vs. 273 ml/s).
- Normal saline did not alter VmaxFRC in CF patients.
- Metaproterenol significantly increased VmaxFRC in CF patients, normalizing the difference between groups (267 vs. 276 ml/s).
Conclusions:
- Infants and young children with CF demonstrate increased bronchomotor tone.
- Bronchoconstriction is a significant factor contributing to airway obstruction in early childhood CF.
- Bronchodilator therapy may be beneficial in managing airway obstruction in young CF patients.
Abstract:
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 technique and was quantitated by the maximal expiratory flow at functional residual capacity (VmaxFRC). For the normal control group there was no significant change in VmaxFRC after the aerosol of either normal saline or metaproterenol. At baseline, the group of infants with CF had significantly lower values of VmaxFRC than did the normal control infants (202 versus 273 ml/s, p less than 0.05). The CF group demonstrated no significant change from baseline VmaxFRC after the aerosol of normal saline. However, after metaproterenol the CF group had a significant increase (p less than 0.001) in VmaxFRC, which eliminated the difference in VmaxFRC 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.