Abstract: Objective To study clinical application of bronchodilation test of tidal breathing lung function test in asthmatic children under 5 years old.
Methods A total of 190 asthmatic children who came to our hospital for diagnosis and treatment between Jan. 1,2018 and Oct. 31,2019 were recruited as research subjects. They were divided into three groups according to their ages: group Ⅰ( 6 months to 1 year old,26 cases) , group Ⅱ(1 to 3 years old,72 cases), group Ⅲ(3 to 5 years old,92 cases). According to the degree of bronchial obstruction, the patients were divided into light, medium and severe groups. All received 0.5% salbutamol. Tidal breathing flowvolume loop and parameters obtained before and after aerosol inhalation were evaluated.〖JP〗
Results (1)There was significant difference in TPTEF/TE and VPEF/VE in 190 asthmatic children and the children in groups Ⅱ before and after inhaling the drug(P<0.05).(2)There was significant difference in TPTEF/TE and VPEF/VE in medium and severe groups before and after inhaling the drug(P<0.05).(3)There was significant difference in the positive rate of bronchodilation test among the three groups with different degrees of obstruction(P<0.05).
Conclusion Bronchodilation test of tidal breathing lung function test can reflect the reversibility of airway obstruction in asthmatic children under 5 years old. Bronchodilation test of tidal breathing lung function test is of great value in the diagnosis of asthmatic children with severe obstruction.

Key words: Bronchial asthma, Tidal breathing lung function, Bronchodilation test, Children