Table 9.
Correlation between the IOS and spirometry parameters in advanced elderly COPD patients
| Z5 (%predicted) | Fres (L/s) | X5 (kPa/L/s) | R5 (%predicted) | R20 (%predicted) | R5–R20 (%predicted) | ||
|---|---|---|---|---|---|---|---|
| FVC (%predicted) | r | −0.377* | −0.264 | 0.280 | −0.334* | −0.110 | −0.466** |
| FEV1 (%predicted) | r | −0.615** | −0.532** | 0.560** | −0.558** | −0.286 | −0.639** |
| FEV1/FVC (%) | r | −0.587** | −0.556** | 0.605** | −0.519** | −0.292 | −0.540** |
| MMEF (%predicted) | r | −0.487** | −0.368* | 0.454** | −0.470** | −0.323* | −0.452** |
Notes:
*
P<0.05.
**
P<0.001.
Abbreviations: IOS, impulse oscillometry; Z5, respiratory impedance; Fres, resonant frequency; X5, respiratory reactance; R5–R20, respiratory resistance; FVC, forced vital capacity; r, Pearson’s correlation coefficient; FEV1, forced expiratory volume in 1 second; MMEF, maximum midexpiratory flow rate.