IOS determine respiration impedance is a sensitive marker of judgement air velocity obstruction,it can replace FEV1 judge the degree of COPD patients airway obstruction.

• IOS法测定呼吸阻抗是判断气道阻塞的敏感指标 ,可以代替FEV 1 判断COPD患者的气道阻塞程度。