Table 2.
Comparison of traditional pulmonary function tests and pulsed oscillatory resistance determination between the carbon dioxide retention and non-carbon dioxide retention COPD
| Carbon dioxide retention (n = 86) | Non-carbon dioxide retention (n = 144) | p value | |
|---|---|---|---|
| Z5%pred | 185.9 (154–216.65) | 162.4 (131.35–199.6) | 0.004 |
| R5%pred | 168 (138.85–197.7) | 148 (126.75–182.75) | 0.008 |
| R5 | 0.52 (0.43–0.61) | 0.49 (0.39–0.57) | 0.057 |
| R20%pred | 123.4 (105.75–139.55) | 117.2 (104.3–135.6) | 0.236 |
| R20 | 0.32 (0.29–0.375) | 0.33 (0.29–0.37) | 0.764 |
| R5-R20 | 0.18 (0.125–0.23) | 0.14 (0.09–0.205) | 0.009 |
| X5 | −0.24 (−0.31--0.16) | −0.19 (− 0.32--0.13) | 0.022 |
| Fres | 22 (18.26–26.19) | 21.2 (17.48–24.61) | 0.173 |
| Ax | 1.89 (1.27–2.57) | 1.54 (0.74–2.44) | 0.011 |
| FEV1 | 0.95 (0.77–1.42) | 1.39 (1.06–1.74) | < 0.001 |
| FEV1%pred | 34.25 (25.4–47.8) | 51.45 (40–61.7) | < 0.001 |
| FEV1/FVC | 48.14 (42.08–56.71) | 56.26 (46.55–62.79) | < 0.001 |
| MMEF75–25%pred | 14.25 (9.7–19.9) | 21.5 (16.1–27.75) | < 0.001 |
| DLCO/VA | 75.47 ± 24.29 | 80.13 ± 24.34 | 0.169 |
| RV/TLC | 59.44 ± 10.11 | 55.98 ± 10.63 | 0.017 |
Abbreviations: PFT Pulmonary function test, FEV1 forced expiratory volume in 1 sec, FVC forced vital capacity, FEV1/FVC forced expiratory volume in 1 sec/forced vital capacity, MMEF25–75% maximal mid expiratory flow, RV/TLC residual volume/total lung capacity, DLCO/VA ratio of carbon monoxide diffusion capacity to alveolar ventilation, %Pred, of the predicted value, Z5 Total respiratory impedance, R5 resistance at 5 Hz, R20 resistance at 20 Hz, X5 reactance at 5 Hz, Fres response frequency, Ax reactance area