OBJECTIVE: To verify if the bronchoprovocation test with 4.5% hypertonic saline solution allows to detect the gradient of response in asthmatic children and adolescents, according to asthma severity. METHODS: 75 asthmatic patients aged six to 18 years-old were evaluated in this cross-sectional study. They were classified according to asthma severity in: intermittent or mild persistent (IM) and moderate or severe persistent (MS). They were also classified according to sensitization to inhaled allergens in atopics: positive skin prick test to Dermatophagoides pteronyssinus, D. farinae and Blomia tropicalis; or non- atopic with negative skin prick tests. All patients underwent a bronchoprovocation test with 4.5% hypertonic saline solution. The result of the bronchoprovocation test was considerd positive if at least a reduction of 20% in the forced expiratory volume in one second (FEV1) was noted. RESULTS: 60 individuals were atopic. The bronchoprovocation test was positive more frequently in the MS group than in the IM one (93 versus 65%). Less time was needed for a 20% fall of FEV1 in the MG compared to the IL group [90 (30 - 330) versus 210 (30 - 690) seconds; p<0.05]. The percentage of FEV1 fall was higher in the MG group than in the IL one [26,4% (14 - 63) versus 20% (0 - 60); p<0.05]. CONCLUSIONS: The 4.5% hypertonic saline solution bronchoprovocation test is safe and easy to perform. It detects a gradient of response in asthmatic children and adolescents regarding asthma severity. Higher frequency of positive tests, shorter time for FEV1 fall, and higher percentage of FEV1 fall were observed in moderate and severe asthmatic patients.
asthma; saline solution, hypertonic; spirometry
