Abstract: Objective To discuss the effect of pulmonary tuberculosis (PTB) in different states of illness on the respiratory impedance and evaluate the clinical significance of impulse oscillation(IOS) to determine the impedance in the patients with PTB.Methods The IOS indices of 60 patients with minimal PTB,48 cases of moderate advanced PTB,40 cases of far advanced PTB and 30 normal cases were compared with each other.Linear correlation was used to analyze the relationship between the impedance and ventilation indices of 148 cases.ResultsResonance frequenc frequency (Fres)、the total impedance(Zrs)、the total airway resistance(R₅)、the central airway resistance(R₂₀)、the peripheral airway resistance(R₅-R₂₀)and the peripheral capucitance(X₅) in the groups of PTB rose gradually with increasing of the seriousness of PTB.Compared with normal cases,the IOS indices of the patients with minimal PTB do not rose obviously(P>0.05).The IOS indices except R₂₀ rose obviously(P0.05)in the patients with moderate advanced PTB.The IOS indices of the patients with far advanced PTB rose obviously(P0.01).The negative correlation was found between IOS indices with the exception of X₅ and ventilation indices.The positive correlation was found between X₅ and ventilation indices.The correlation relationship between Fres and MVV are strongest in all.Conclusion The differences of effect in the patients with PTB on the impedance are very great.The applied foreground of IOS in the clinical PTB will be good.

Key words: Tuberculosis,pulmonary, Respiratory impedance, Impulse oscillation