Table 3.
Respiratory parameters of 212 COPD patients stratified according to the median value of 5/250 impedance ratio (124.4 for males; 122.7 for females)
| Characteristics | 5/250 impedance ratio
|
||
|---|---|---|---|
| Below median value (n=106) | Above median value (n=106) | P-value* | |
| FEV1 (% predicted) | 42.5±18.3 | 47.7±19.3 | <0.05 |
| VC (% predicted) | 66.0±17.8 | 73.3±19.0 | <0.005 |
| RV (% predicted) | 243.1±66.7 | 258.9±68.6 | ns |
| ITGV (% predicted) | 183.3±49.1 | 195.1±48.9 | ns |
| IC/TLC | 0.3±0.8 | 0.2±0.3 | ns |
| MIP (cm·H2O) | 49.9±17.7 | 61.7±20.8 | <0.001 |
| MEP (cm·H2O) | 72.2±24.2 | 84.5±27.3 | <0.001 |
| MRC dyspnea scale | 3.8±0.4 | 3.6±0.5 | <0.05 |
Notes: Data are presented as mean ± standard deviation.
*
P<0.05.
Abbreviations: 5/250 impedance ratio, ratio between Z at 5 kHz and Z at 250 kHz; FEV1, forced expiratory volume in 1 second; VC, vital capacity; RV, residual volume; ITGV, intrathoracic gas volume; IC, inspiratory capacity; TLC, total lung capacity; MIP, maximum inspiratory pressure; MEP, maximum expiratory pressure; MRC, Medical Research Council; ns, not significant.