Table 2.
Diaphragm EMG, ventilation during wakefulness and NREM sleep
| COPD (n=19) | Overlap (n=16) | |||||||
|---|---|---|---|---|---|---|---|---|
| Characteristics | Wakefulness | NREM | △% | p Value | Wakefulness | NREM | △% | p Value |
| EMGdi%max | 29.5±13.3 | 23.0±8.9 | 22 | 0.006 | 29.3±15.8 | 27.3±14.7 | 7 | 0.38 |
| VE (L) | 8.6±2.0 | 6.5±1.5 | 24 | <0.001 | 8.3±2.0 | 6.1±1.8 | 27 | 0.001 |
| VT (L) | 0.47±0.11 | 0.37±0.09 | 22 | 0.001 | 0.47±0.11 | 0.36±0.10 | 24 | 0.001 |
| VT/EMGdi | 0.39±0.23 | 0.37±0.21 | 5 | 0.92 | 0.35±0.21 | 0.28±0.19 | 20 | 0.041 |
| ETCO2 (%) | 4.5±0.5 | 4.5±0.6 | 0 | 0.89 | 4.7±0.7 | 4.7±0.8 | 0 | 0.48 |
| RR | 18.4±3.1 | 17.8±2.1 | 3 | 0.33 | 17.6±1.7 | 17.2±2.9 | 2 | 0.35 |
| Normal (n=12) | OSA (n=14) | |||||||
| EMGdi%max | 12.6±3.7 | 12.2±3.3 | 3 | 0.84 | 14.2±7.9 | 23.4±10.8 | 65 | 0.001 |
| VE (L) | 8.3±1.6 | 7.5±1.3 | 10 | 0.07 | 8.0±2.7 | 6.3±1.9 | 21 | 0.006 |
| VT (L) | 0.50±0.09 | 0.49±0.10 | 2 | 0.56 | 0.48±0.16 | 0.39±0.10 | 19 | 0.008 |
| VT/EMGdi | 0.69±0.18 | 0.69±0.20 | 0 | 0.91 | 0.56±0.24 | 0.28±0.13 | 49 | 0.001 |
| ETCO2 (%) | 4.8±0.3 | 5.0±0.3 | 4 | 0.002 | 4.5±0.8 | 4.6±0.9 | 3 | 0.18 |
| RR | 16.7±2.3 | 15.6±2.3 | 7 | 0.10 | 16.6±3.0 | 16.0±2.3 | 4 | 0.27 |
△%, percentage change compared with wakefulness; EMGdi%max, percentage of maximal EMGdi; ETCO2, end-tidal CO2; NREM, non-rapid eye movement; p value, comparison of wakefulness and NREM; RR, respiratory rate; VE, minute ventilation; VT, tidal volume; VT/EMGdi, the ratio of tidal volume to peak root mean square of EMGdi.