Respiratory resistance and reactance in stable COPD patients: Rrs5: 0.403 ± 0.083kPa / L / s, Rrs20: 0.338 ± 0.064kPa / L / s, Xrs5: - 0.132 ± 0.087kPa / L / s, in exacerbations COPD patients Rrs5: 0.501 ± 0.135kPa / L / s, Rrs20: 0.383 ± 0.098kPa / L / s, Xrs5: - 0.176 ± 0.063kPa/L/s.