Effects Of Inhaled Corticosteroids On Lung Function In Children With Post-infectious Bronchiolitis Obliterans In Remission

Objective:The purpose of the study was to evaluate the effects of inhaled corticosteroids on lung function in remission of post-infectious bronchiolitis obliterans（PIBO）,and to evaluate the effects of continuous inhaled corticosteroids and intermittent inhaled corticosteroids on lung function in remission of PIBO.Method:The clinical data of 34 patients with PIBO in remission who were treated and followed up in the First Hospital of Jilin University from January 2007 to January 2021 were retrospectively analyzed.All subjects were divided into group A and group B according to the treatment regimens.Patients in group A received continuous inhaled corticosteroids therapy（2 times a day）,and patients in group B received intermittent inhaled corticosteroids therapy（inhaled corticosteroids after acute respiratory tract infection or wheezing）.Different lung function tests were performed at different ages.Tidal breathing lung function tests were performed in PIBO patients aged≤5 years,and lung ventilation function test and bronchial dilation test were performed in PIBO patients aged>5 years.Lung function was assessed at the beginning of follow-up and at the end of follow-up（1 year of corticosteroids inhalation）.In this study,the general data,clinical manifestations,lung function results and other data of all subjects were collected,and the clinical data of the two groups were statistically analyzed.Result:1.After 1 year of inhalation of corticosteroids,patients≤5 years old,time to peak tidal expiratory flow as a proportion of expiratory time（TPTEF/TE）and volume to peak expiratory flow as a proportion of exhaled volume（VPEF/VE）were no significant difference between the two groups.In patients aged>5 years old,forced vital capacity（FVC）and forced expiratory volume in 1 second（FEV₁）were67.55±19.01 and 55.13±23.43,which were significantly higher than at the beginning of follow-up.2.After 1 year of inhalation of corticosteroids,tidal volume per kilogram（V_T/Kg）,TPTEF/TE and VPEF/VE were no significant difference between the two groups of A and B in patients aged≤5 years old,compared with those at the beginning of follow-up.The difference of V_T/Kg,TPTEF/TE and VPEF/VE between the end and the beginning of follow-up in group A was 0.31±1.37,2.35±3.12 and1.02±2.35,showing an upward trend.The difference of V_T/Kg,TPTEF/TE and VPEF/VE between the end and the beginning of follow-up in group B was-0.93±1.34,-0.18±2.00 and-0.52±1.83,showing a downward trend.3.After 1 year of inhalation of corticosteroids,patients>5 years old,FVC,FEV₁ and maximal midexpiratory flow velocity 25-75%(MMEF_25-75%)of group A were 70.96±21.92,60.75±24.95 and 38.71±25.61,which were significantly higher than at the beginning of follow-up.FVC,FEV₁,FEV₁/FVC,MMEF_25-75%in group B showed no significant differences compared with those at the beginning of follow-up.The difference of FEV₁ and MMEF_25-75%between the end of follow-up and the beginning of follow-up in group A was significantly higher than that in group B,and there was no significant difference in FVC and FEV₁/FVC between groups A and B.However,the difference of FEV₁/FVC in group A was 0.43±12.08,showing an increasing trend.The difference of FEV₁/FVC in group B was-10.13±11.13,showing a downward trend.4.52.94%of PIBO patients who aged>5 years old were positive for bronchial dilation tests.5.During the follow-up period,there was no significant difference in the proportion of respiratory tract infection between group A and group B,and no other complications or adverse events occurred in both groups.Conclusion:1.Inhaled corticosteroids can effectively improve lung function and relieve airway obstruction in PIBO patients>5 years of age in remission,especially continuous inhaled corticosteroids therapy.2.For PIBO patients aged≤5 years in remission,inhaled corticosteroids may have positive therapeutic significance,especially for continuous inhaled corticosteroids therapy.3.Patients with PIBO may have reversible airflow limitation.