Objective To investigate the changes of small airway function and diffusing capacity in patients with mild asthma before and after bronchial provocation test (BPT).Methods BPT was performed in suspected asthma patients with chief complaints of paroxysmal wheeze,chest tightness and cough，but with normal chest X-ray and baseline pulmonary function.BPT positive group was regarded as asthma group，while BPT negative group as control group.Lung volume，ventilatory function and diffusing capacity were measured before and after BPT and compared between the asthma and control groups.Results （A）No statistical differences were found in FEV1%，FEV1/FVC，FVC%，VC%，TLC%，FRC%，RV%，RV/TLC between the asthma and control groups before BPT.FEV1/FVC and FVC% were significantly decreased (all Plt;0.01)，while FRC% (Plt;0.05)，RV% (Plt;0.01) and RV/TLC (Plt;0.01) increased significantly in the asthma group after BPT compared with the control group.The decline rate of FEV1/FVC and FVC% and the increase rate of TLC%，RV%，RV/TLC were significantly higher in the asthma group than those in the control group (all Plt;0.01).（B）Compared with the control group，FEF25%-75% (Plt;0.05)，Vmax75% (Plt;0.01) and Vmax50% (Plt;0.05) were significantly lowered before BPT，while the above parameters and Vmax25% were significantly decreased after BPT in the asthma group (all Plt;0.01).The decline rate of FEF25%-75%，Vmax75%，Vmax50% and Vmax25% was significantly higher in the asthma group than those in the control group (all Plt;0.01).（C）There was no statistical difference in DLCO in both groups before and after BPT.Conclusions Patients with mild asthma had small airways impairment before BCT which further declined after BPT.However,no impairment of diffusion capacity was found before or after BPT.
Objective To investigate the relationship of small airway function with airway sensitivity and reactivity and assess the factors influencingairway hyperresponsiveness (AHR).Methods Data of consecutive subjects with suspected asthma who had a≥20% reduction in FEV1 after ≤12.8 mmol/L cumulative doses of methacholine were analyzed from January 2005 to April 2006.Airway sensitivity was assessed by the cumulative dose of methacholine required to cause 20% reduction in FEV1 (PD20).Airway reactivity was analyzed using the slope of the dose-response curve (DRS).The DRS was defined as the reduction in FEV1 from baseline after the final dose of methacholine inhaled divided by the cumulative dose inhaled.Because of their highly skewed distribution，DRS was logarithmically transformed (log10) for all analysis.Results A total of 184 consecutive subjects aged 16 to 80 years was enrolled.There were 70 male (38.0%) and 114 female (62.0%) subjects.Subjects with higher airway sensitivity，indicated by lower PD20，also had a lower Vmax50% and Vmax25%，and vise versa.PD20 was negatively correlated wit log10DRS (r=-0.874，Plt;0.01).In a simple linear regression model，log10DNS was significantly correlated with FEV1%，Vmax50% or Vmax25% respectively (the determinant r2 were 0.062，0.097 and 0.085，respectively，all Plt;0.01).In a multiple linear regression model that included age，height，and percentage of predicted FEV1，Vmax50% and Vmax25% accounted for 3.9% and 2.6%，respectively，of variability in airway reactivity.The association between Vmax50% and log10DNS was significant in both male and female subjects.The r2 was higher in male subjects.The subjects were divided into three age groups and the association between Vmax50% or Vmax25% and log10DNS was higher in female than in male for age≤25 years，higher in male than in female for 25 -45 years.No association was found for agegt;45 years in both males and females.Conclusions Impaired small airway function is associated with higher airway sensitivity and reactivity to methacholine in subjects with suspected asthma.
Objective To study the efect of montelukast for improving bronchial hyperresponsiveness (BHR) in treatment of bronchiolitis. Methods Four hundreds infants, 3 to 24 months old, hospitalized with acute bronchiolitis in three Hospitals (Urumqi Children’s Hospital, Pediatrics Department of First Ailiated Hospital of Xinjiang Medical University, and Pediatrics Department of Army General Hospital) from January, 2007 to January, 2008, were randomly assigned into four groups: placebo group (n=92), budesonide group (n=91), montelukast short-course group (7 days, n=88), and montelukast long-course group (28 days, n=90). Main outcome measure was BHR ater treatment, including recurrent bronchiolitis wheezing and asthma incidence rate. Secondary measures were changes in serum T-IgE level and eosinophilic cationic protein (ECP) level. Results All four groups were comparable at baseline. No signiicant diferences were observed between placebo group and budesonide group in changes of serum T-IgE (F=6.17, P=0.00), ECP (F=8.13, P=0.00), recurrent post-bronchiolitis-wheezing (χ2=49.46, P=0.00) and asthma incidence rate (χ2=27.21, P=0.00). Ater treatment with montelukast, there was statistical signiicance in T-IgE and ECP level, times of recurrent bronchiolitis wheezing and asthma incidence rate, as follows, montelukast short-course group versus placebo group (F=12.56, P=0.00), montelukast short-course group versus budesonide group (F=7.22, P=0.00), montelukast long-course group versus placebo group (F=20.48, P=0.00), montelukast long-course group versus budesonide group (F=13.56, P=0.00), montelukast short-course group versus montelukast long-course group (F=1.04, P=0.00). Conclusions Budesonide treatment for 7 days can not improve bronchial hyperresponsiveness induced by bronchiolitis, while montelukast does, that is, montelukast can decrease both the times of bronchiolitis wheezing and asthma incidence rate. Long-course treatment of montelukast is superior to that of short-course.