Table 2.
Sleep quality and sleep disordered breathing at baseline
| Variable | Control (n=8), mean±SD | COPD (n=17), mean±SD | Statistics |
|---|---|---|---|
| Total sleep time (minutes) | 396.3±39.8 | 376.6±87.7 | n.s. |
| Sleep efficiency (%) | 84.6±4.3 | 79.6±17.9 | n.s. |
| Sleep latency (minutes) | 15.8±16.9 | 14.9±20.7 | n.s. |
| REM sleep latency (minutes) | 89.2±33.6 | 99.3±59.5 | n.s. |
| WASO (minutes) | 55.4±15.4 | 79.4±67.4 | n.s. |
| Sleep stage N1 (%) | 11.1±6.0 | 13.9±9.0 | n.s. |
| Sleep stage N2 (%) | 50.2±14.7 | 52.0±9.0 | n.s. |
| Sleep stage N3 (%) | 16.7±11.5 | 15.7±11.7 | n.s. |
| Sleep stage REM (%) | 21.9±8.5 | 18.4±6.2 | n.s. |
| Arousal index (n/h) | 10.3±6.6 | 11.0±5.3 | n.s. |
| Arousal index NREM (n/h) | 9.4±5.4 | 10.0±6.6 | n.s. |
| Arousal index REM (n/h) | 9.3±7.8 | 12.2±10.4 | n.s. |
| RDI (n/h) | 10.9±9.6 | 8.0±7.8 | n.s. |
| RDI NREM (n/h) | 9.5±8.2 | 5.9±7.1 | n.s. |
| RDI REM (n/h) | 17.0±19.4 | 18.6±20.9 | n.s. |
| Average SaO2 (%) | 95.2±1.8 | 93.9±2.9 | n.s. |
| tcCO2 mean awake (mmHg) | 39.6±6.3 | 42.4±6.1 | n.s. |
| tcCO2 mean NREM (mmHg) | 43.0±7.0 | 43.7±5.5 | n.s. |
| tcCO2 mean REM (mmHg) | 50.6±12.9 | 53.0±12.5 | n.s. |
Abbreviations: n/h, numbers/hour; n.s., not significant; N1–N3, non-rapid eye movement sleep stages 1–3; RDI, respiratory disturbance index; NREM, non-REM; REM, rapid eye movement sleep; SaO2, O2 saturation; tcCO2, transcutaneous carbon dioxide; WASO, wakefulness after sleep onset.