TABLE 1

Patient characteristics

CharacteristicsComparative datasetEffect of O2Effect of ACZ
BaselineO2BaselineACZ
Demographics
 Males/females n/n19/99/27/5
 Age years48±1049±1048±7
 Body mass index kg·m−235±634±734±7
 CPAP cmH2O10.9±2.910.6±2.410.5±2.0
Sleep
 Time in bed min416±37403±41402±30428±40413±39
 TST min321±51325±55299±57340±42338±44
  Supine non-REM261±63273±60243±65*285±68296±52
  Supine REM28±1737±2435±3032±1430±11
Respiratory event characteristics
 AHI events·h−133 (32)58 (56)42 (38)*48 (17)25 (20)
  Supine non-REM33 (37)56 (55)42 (43)*50 (19)24 (22)*
  REM/non-REM1.18±0.831.09±0.841.38±0.920.94±0.381.30±1.10
  Obstructive apnoea index# events·h−12.1 (12.6)31 (29)16 (43)4.86 (7.28)0.63 (6.21)
  Mixed apnoea index# events·h−10.00 (0.53)0.37 (4.55)0.22 (0.60)0.00 (0.65)0.00 (0.04)
  Central apnoea index# events·h−10.00 (0.50)0.39 (5.32)0.00 (0.27)*0.00 (0.16)0.00 (0.00)
  Hypopnoea index# events·h−133 (22)12 (14)11 (11)39 (24)18 (15)
 Arousal index# events·h−141 (24)60 (44)51 (35)39 (10)32 (7)
 Mean O2 saturation# %94±293±397±1*94±195±2*
 Minimum O2 saturation# %83±678±789±4*82±485±5
 Stable breathing#,¶ %18±1814±1714±1610±1220±17
 Event duration s26±623±427±5*30±1036±10*
 Inter-event interval s44±1038±849±8*49±1361±14*
Ventilatory control
 Standard loop gain+0.57±0.210.46±0.26§0.32±0.06ƒ0.60±0.330.35±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.