Assessment of respiratory impedance during deep-slow breathing with impulse oscillometry in patients with chronic obstructive pulmonary disease

Abstract

Objective: To observe the relationship of deep-slow respiratory pattern and respiratory impedance(RI) in patients with chronic obstructive pulmonary disease (COPD).Methods: RI under normal respiration and during deep-slow respiration was measured one after the other with impulse oscillometry for 8 patients with COPD and for 9 healthy volunteers as control.Results: When respiration was changed from normal pattern to the deep-slow pattern, the tidal volume increased and respiratory frequency significantly decreased in both groups (P < 0. 01), the total respiratory impedance (Z respir) showed a decreasing trend in COPD group, but with no obvious change in the control group. No change in the resonant frequency (fres) was found in both groups, and the respiratory viscous resistance obviously decreased in the COPD group(R5: P=0.0168; R20: P=0.0498; R5-R20: P=0.0388), though in the control group it was unchanged.Conclusion: IOS detection could reflect the response heterogeneity of different compartments of respiratory system during tidal breathing. During deep-slow respiration, the viscous resistance in both central airway and peripheral airway was decreased in patients with COPD. RI measurement by impulse oscillometry may be a convenient pathophysiological method for studying the application of breathing exercise in patients with COPD.