title: Response to inhaled bronchodilators and nonspecific airway hyperreactivity in children with cystic fibrosis.
abstract: We tested the hypothesis that children with CF who have a significant response to bronchodilator (BD) would respond positively to standard methacholine (Mch) challenge. Our objective was to correlate the response to BD with the concentration that produced a 20% fall (PC20) in forced expiratory volume in 1 second (FEV1). We studied 22 patients (12 males), aged 10.5 +/- 0.7 years (mean +/- SE), with a Shwachman-Kulczycki score 82 +/- 2.6 and baseline FEV1 of 80 +/- 4.5% predicted. Baseline expiratory flows, static lung volumes, and airway resistance were measured before and 30 min after inhaled salbutamol. On a separate day, within 2 weeks, a Mch challenge was given, with doubling concentrations from 0.03 to 8.0 mg/mL. A positive challenge was defined as a PC20 less than or equal to 2.0 mg/mL, and a positive response to BD as a greater than 6% of FEV1 increase. Mch challenge yielded 17 responders (R) with a PC20 of 0.5 +/- 0.1 mg/mL, and 5 nonresponders (NR) with a PC20 of 8.8 +/- 2.9 mg/mL. Baseline FEV1 was 77 +/- 5.3% predicted in R compared to 89 +/- 6.3% in NR (P = less than 0.001). History of springtime rhinitis was positive in 9/17 R and 2/5 NR. No significant correlation was found between baseline FEV1 and PC20, or between change in FEV1 post-BD and PC20. A greater than 6% increase in FEV1 was seen in 14/17 R (83% sensitivity) and in none of the 5 NR (100% specificity). In R, 8/17 patients had baseline FEV1 less than 80% predicted, compared to 1/5 in NR.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Pediatrics, University of Manitoba, Winnipeg.
authors.forename: I
authors.initials: I
authors.lastname: Sanchez
authors.forename: R E
authors.initials: RE
authors.lastname: Powell
authors.forename: V
authors.initials: V
authors.lastname: Chernick
mesh_terms: D000293:Adolescent; D000420:Albuterol / Q000627:therapeutic use*; D001985:Bronchial Provocation Tests; D001993:Bronchodilator Agents / Q000627:therapeutic use*; D002648:Child; D003550:Cystic Fibrosis / Q000188:drug therapy*; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D012123:Pulmonary Ventilation / Q000187:drug effects*; D012129:Respiratory Function Tests / Q000379:methods
chemical_list: D001993:Bronchodilator Agents; D016210:Methacholine Chloride; D000420:Albuterol