OBJECTIVETo study the clinical significance of tidal breathing lung function test in 1-4 years old children with wheezing diseases.

METHODSA total of 141 1-4 years old children with wheezing diseases were enrolled as the observed groups (41 cases of asthma, 54 cases of asthmatic bronchitis, and 46 cases of bronchopneumonia). Thirty children without respiratory diseases were enrolled as the control group. All the recruits underwent tidal breathing lung function test. The observed groups underwent bronchial dilation test, and tidal breathing flow volume (TBFV) parameters were evaluated before and after bronchial dilation test.

RESULTSThe observed groups showed obstructive ventilatory disorder (65%) according to the TBFV loop, and their ratio of time to peak tidal expiratory flow (TPTEF) to total expiratory time (TE) and ratio of volume to peak expiratory flow (VPEF) to total expiratory volume (VE) were significantly lower than in the control group (P<0.05). The asthma subgroup had significantly improved TPTEF/TE and VPEF/VE after bronchial dilation test (P<0.05). Taking an improvement rate of ≥ 15% either for TPTEF/TE or for VPEF/VE as an indicator of positive bronchial dilation test, the bronchial dilation test had a sensitivity of 47% and a specificity of 84% in diagnosing asthma in 1-4 years old children. The positive rate was 28% among the children in the asthma subgroup with an TPTEF/TE ratio of ≥ 23% before bronchial dilation test, versus 65% in those with an TPTEF/TE ratio of <23%.

CONCLUSIONSObstructive ventilatory disorder is the main impairment of tidal breathing lung function in 1-4 years old children with wheezing diseases. Tidal breathing bronchial dilation test can reflect a reversal of airway obstruction to a certain extent. The sensitivity of bronchial dilation test for the diagnosis of asthma is not satisfactory in 1-4 years old children with wheezing diseases, but this test has a relatively high diagnostic value in children with severe airway obstruction.