The Application of Impulse Oscillometry on the Diagnosis of ACOS,Asthma and COPD.

ACOS,asthma and COPD are prevalent diseases with similar manifestations and different type airway impairments. The differential diagnosis is not easy because the patients always complain of the similar symptoms and are not able to complete spirometry well. Impulse Oscillometry System (IOS) is capable of identifying airway obstruction and reactions to bronchodilators by providing impedance data and curves. IOS is also a patient-friendly and valuable tool with minimal demands on patient and requiring only passive cooperation. IOS is a tool to measure lung function during tidal breathing. The output is a measure of respiratory impedance (Zrs), which include the respiratory resistance (Rrs) and respiratory reactance (Xrs) measured over a range of frequencies (usually from 3 to 35 Hz). The main objective of this study is to investigate the ability of IOS to measure small airway disease by providing different impedance profiles for participants with ACOS,asthma and COPD. Another objective of this study is to investigate the differential ability to identify three diseases by measuring airway impedance and reactions to bronchodilators. First,participants completed the IOS test.Second,participants inhaled salbutamol for 200g 15 minutes to repeat the IOS.The investigators collect these 2 data for analysis.