Table 2.
Change from exacerbation to stable state in lung function and FRI parameters
| Parameters | At exacerbation | At stable state | Mean change | Significance |
|---|---|---|---|---|
| FEV1 (L) | 1.15±0.43 | 1.31±0.50 | 0.16±0.25 | <0.01* |
| FEV1 (% predicted) | 45.92±15.05 | 51.89±16.83 | 5.97±9.15 | <0.01* |
| iVawFRC (mL) | 34.78±14.20 | 36.28±12.87 | 1.50±7.65 | 0.19 |
| iVawTLC (mL) | 54.79±16.05 | 56.49±16.32 | 1.70±4.65 | 0.02* |
| FRC (L) | 4.83±1.31 | 4.62±1.17 | −0.22±0.58 | 0.01* |
| iVlobeFRC (L) | 5.01±1.18 | 4.75±1.10 | −0.25±0.61 | <0.01* |
| TLC (L) | 6.72±1.42 | 6.74±1.30 | 0.02±0.60 | 0.81 |
| iVlobeTLC (L) | 6.47±1.18 | 6.49±1.14 | 0.02±0.41 | 0.76 |
| Raw (kPa·s/L) | 0.71±0.24 | 0.63±0.34 | −0.10±0.29 | 0.04* |
| iRawFRC (kPa·s/L) | 0.11±0.13 | 0.06±0.08 | −0.04±0.12 | 0.03* |
| iRawTLC (kPa·s/L) | 0.04±0.03 | 0.04±0.02 | −0.01±0.02 | 0.03* |
| IC (L) | 1.96±0.59 | 2.20±0.73 | 0.14±0.27 | <0.01* |
| RV (L) | 3.87±1.23 | 3.66±1.02 | −0.21±0.76 | 0.07 |
| TCO (mmol/min/kPa) | 3.52±1.50 | 3.53±1.63 | 0.06±0.67 | 0.54 |
| Patient-reported outcomes | ||||
| SGRQ | 62.18±15.31 | 48.60±20.51 | −14.62±18.88 | <0.01* |
| CCQ | 3.40±1.20 | 2.41±1.30 | −1.00±1.45 | <0.01* |
| CAT | 24.06±7.81 | 18.23±8.13 | −5.83±11.28 | <0.01* |
| mMRC | 3.11±1.15 | 2.43±1.17 | −0.67±1.23 | <0.01* |
Notes: Values are shown as mean ± SD. Correlations are reported as p-value and r.
p-value <0.05.
Abbreviations: CAT, COPD Assessment Test; CCQ, Clinical COPD Questionnaire; FEV1, forced expiratory volume in 1 second; FRC, functional residual capacity; FRI, functional respiratory imaging; IC, inspiratory capacity; iRaw, airway resistance measured by FRI; iVaw, airway volume measured by FRI; iVlobe, lobar volume measured by FRI; mMRC, modified Medical Research Council dyspnea scale; Raw, airway resistance measured by plethysmography; RV, residual volume; SD, standard deviation; SGRQ, the Saint George’s Respiratory Questionnaire; TCO, transfer factor for carbon monoxide; TLC, total lung capacity.