Value of airway responsiveness measurement in the diagnosis of infant cough variant asthma / 中华实用儿科临床杂志

ABSTRACT

Objective:To explore the value of airway responsiveness measurement by the tidal lung function test combined with the bronchial provocation test (BPT) in the diagnosis of infant cough variant asthma (CVA), and to provide evidence for clinical diagnosis of CVA.Methods:The tidal lung function test and BPT test results of 131 cases of chronic cough (including 70 CVA cases and 61 non-CVA cases) treated in the Asthma Specialist Clinic of Children′s Hospital Affiliated to Chongqing Medical University from January 2018 to September 2018 were retrospectively analyzed.The results between CVA group and non-CVA group were compared.Results:There was no significant difference in the basal tidal lung function detection results between the CVA group and non-CVA group ( P>0.05). The positive rate of BPT in the CVA group was significantly higher than that in the non-CVA group (98.6% vs. 27.9%, χ2=30.757, P<0.01). Among the patients with positive BPT, the proportion of patients with moderate and severe positive reactions in the CVA group was significantly higher than that in the non-CVA group (40.0% vs. 3.3%, 15.7% vs. 0, χ2=24.894, 20.464, all P<0.01). During BPT test process, a significantly greater number of patients showed wheezing and a significant decrease in oxygen saturation(SpO 2) in the CVA group than in the non-CVA group (50.0% vs.0, 91.4% vs.45.9%, χ2=32.169, 36.544, all P<0.01), while the number of patients with severe cough and shortness of breath was similar in both groups (all P>0.05). After the application of bronchodilator or oxygen inhalation, the symptoms of polypnea and wheezing disappeared in all children.The values of the ratio of the time to reach peak tidal expiratory flow to total expiratory time[(TPTEF/TE)%] and the ratio of the volume required to reach peak tidal expiratory flow to total expiratory volume[(VPTEF/VE)%] recovered to more than 80% of the basic values and SpO 2 up to 95%. Conclusions:The tidal lung function test combined with the BPT test is of certain significance for the diagnosis and differential diagnosis of CVA infants.CVA can be better diagnosed based on the degree of BPT and the clinical manifestations during the course of the test.