TABLE 1.
Patient characteristics
| Characteristics | Comparative dataset | Effect of O2
|
Effect of ACZ
|
||
|---|---|---|---|---|---|
| Baseline | O2 | Baseline | ACZ | ||
| Demographics | |||||
| Males/females n/n | 19/9 | 9/2 | 7/5 | ||
| Age years | 48±10 | 49±10 | 48±7 | ||
| Body mass index kg·m−2 | 35±6 | 34±7 | 34±7 | ||
| CPAP cmH2O | 10.9±2.9 | 10.6±2.4 | 10.5±2.0 | ||
| Sleep | |||||
| Time in bed min | 416±37 | 403±41 | 402±30 | 428±40 | 413±39 |
| TST min | 321±51 | 325±55 | 299±57 | 340±42 | 338±44 |
| Supine non-REM | 261±63 | 273±60 | 243±65* | 285±68 | 296±52 |
| Supine REM | 28±17 | 37±24 | 35±30 | 32±14 | 30±11 |
| Respiratory event characteristics | |||||
| AHI events·h−1 | 33 (32) | 58 (56) | 42 (38)* | 48 (17) | 25 (20) |
| Supine non-REM | 33 (37) | 56 (55) | 42 (43)* | 50 (19) | 24 (22)* |
| REM/non-REM | 1.18±0.83 | 1.09±0.84 | 1.38±0.92 | 0.94±0.38 | 1.30±1.10 |
| Obstructive apnoea index# events·h−1 | 2.1 (12.6) | 31 (29) | 16 (43) | 4.86 (7.28) | 0.63 (6.21) |
| Mixed apnoea index# events·h−1 | 0.00 (0.53) | 0.37 (4.55) | 0.22 (0.60) | 0.00 (0.65) | 0.00 (0.04) |
| Central apnoea index# events·h−1 | 0.00 (0.50) | 0.39 (5.32) | 0.00 (0.27)* | 0.00 (0.16) | 0.00 (0.00) |
| Hypopnoea index# events·h−1 | 33 (22) | 12 (14) | 11 (11) | 39 (24) | 18 (15) |
| Arousal index# events·h−1 | 41 (24) | 60 (44) | 51 (35) | 39 (10) | 32 (7) |
| Mean O2 saturation# % | 94±2 | 93±3 | 97±1* | 94±1 | 95±2* |
| Minimum O2 saturation# % | 83±6 | 78±7 | 89±4* | 82±4 | 85±5 |
| Stable breathing#,¶ % | 18±18 | 14±17 | 14±16 | 10±12 | 20±17 |
| Event duration s | 26±6 | 23±4 | 27±5* | 30±10 | 36±10* |
| Inter-event interval s | 44±10 | 38±8 | 49±8* | 49±13 | 61±14* |
| Ventilatory control | |||||
| Standard loop gain+ | 0.57±0.21 | 0.46±0.26§ | 0.32±0.06f | 0.60±0.33 | 0.35±0.21* |
Data are presented as mean±SDor median (interquartile range), unless otherwise stated. ACZ: acetazolamide; CPAP: continuous positive airway pressure; TST: total sleep time; REM: rapid eye movement; AHI: apnoea–hypopnoea index.
#
measured in supine non-REM sleep
¶
stable breathing (no events or arousals for ≥5 min)
+
ratio of feedback response to a 1-cycle·min−1 oscillatory disturbance as measured using CPAP drops except for in the O2 study, when proportional ventilation was used in some individuals
§
proportional assist ventilation used in nine individuals
ƒ
proportional assist ventilation used in seven individuals.
*
p<0.05 versus baseline.