Validity of Fractional Exhaled Nitric Oxide and Impulse Oscillometry in Patients With Cough Variant Asthma
Validity of Fractional Exhaled Nitric Oxide and Impulse Oscillometry in Patients With Cough Variant Asthma
The aim of the research is to evaluate the clinical value of fractional exhaled nitric
 oxide(FeNO) ,impulse oscillometry(IOS) and mid-expiratory flow (MEF) in patients with cough
 variant asthma.
The present study has the following objectives:

 to evaluate the relationship between BHR and mid-expiratory flow, to assess the diagnostic
 accuracy of fractional exhaled nitric oxide，impulse oscillometry and mid-expiratory flow in
 CVA with special regard to its discriminating value between CVA and other causes of a chronic
 cough, to estimate prognostic value of BHR and fractional exhaled nitric oxide (FeNO) count
 in predicting response to asthma treatment.
Inclusion Criteria:

 age 18-65 years old. Cough as the sole or predominant symptom lasting for at least 8 weeks,
 with no radiographic evidence of lung diseases.

 Exclusion Criteria:

 treatment of any oral corticosteroid in the last 4 weeks, and respiratory tract infection
 within 8 weeks.

 smoking (min. 6 months) had asthma or other lung diseases, including obliterative
 bronchiolitis, bronchiectasis,and cystic fibrosis.