Evaluation of the magnitude of the bronchodilator response in children and adolescents with asthma.
OBJECTIVE
Bronchodilator response criteria have been determined in adults; however, data applicable to children and adolescents are scarce. We measured pulmonary function in asthmatic patients to determine the bronchodilator response.


METHODS
A blind study.


METHODS
Outpatient clinic of Pneumology Unit, Instituto da Crianca and Center of Asthma Care and Research, University Hospital, University of Sao Paulo Medical School.


METHODS
Sixty patients aged 6 to 20 years (median, 12 years).


METHODS
Spirometry and plethysmography were performed before and after blind placebo and bronchodilator inhalation (400 mug salbutamol by metered-dose inhaler).


RESULTS
Approximately 90% of the patients had mild-to-moderate persistent asthma. The mean FEV(1) at baseline was 79.6% of the predicted value. Distribution of variations of the different pulmonary function parameters was analyzed after placebo inhalation. The 95th percentile was adopted as a criterion for a significant bronchodilator response. After the bronchodilator test, the patients were classified based on criteria derived from the placebo inhalation and the American Thoracic Society guidelines. Parameters established as cutoff values were 265 mL, 14.2% and 10% FEV(1) expressed as absolute volume, percentage compared with that at baseline and percentage of the predicted value, respectively, and 55% specific airway conductance (sGaw) expressed as a percentage compared with that at baseline. Based on the spirometric data, 37 patients (61%) had reversibility of obstruction, while 48 patients (80%) were classified as responders based on the analysis of variations in sGaw. The classifications based on variations in FEV(1) expressed as absolute volume and percentage of the predicted value showed a substantial correlation with the international classification.


CONCLUSIONS
The cutoff values established for the assessment of the bronchodilator response in the present population agree with those reported in the literature. sGaw was the most sensitive parameter for the identification of changes in airway caliber.
Bussamra
Maria Helena
MH
Unidade de Pneumologia do Instituto da Criança, University of São Paulo Medical School, São Paulo, SP, Brazil. nena.ferreira@uol.com.br
Cukier
Alberto
A
Stelmach
Rafael
R
Rodrigues
Joaquim Carlos
JC
D000293:Adolescent; D000328:Adult; D000402:Airway Obstruction / Q000188:drug therapy; D000403:Airway Resistance / Q000187:drug effects*; D000420:Albuterol / Q000008:administration & dosage*; D001249:Asthma / Q000188:drug therapy*; D001993:Bronchodilator Agents / Q000008:administration & dosage*; D002648:Child; D004311:Double-Blind Method; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D008176:Lung Volume Measurements; D008297:Male; D036501:Metered Dose Inhalers; D010991:Plethysmography; D013147:Spirometry; D013223:Statistics as Topic
D001993:Bronchodilator Agents; D000420:Albuterol