Table 3 Effect of initial CPAP therapy on overnight sleep parameters in patients allocated to longer term CPAP or BVS therapy
CPAP groupBVS groupp Value
Effective CPAP level (cm H2O)14 (3)13 (2)0.65
Min Spo2 (%)70 (12)74 (10)0.27
%TST <90 (%)39 (16–80)57 (14–86)0.66
AHI (events/h)22 (29)13 (12)0.22
Sleep efficiency (%)73 (18)80 (12)0.18
% REM23 (12)22 (12)0.75
Change Tcco2 NREM-REM (mm Hg)5 (3)*4 (2)†0.25
  • Data presented as mean (SD) or median (interquartile range) as appropriate.

  • BVS, bilevel ventilatory support; CPAP, continuous positive airway pressure; Spo2, oxygen saturation; TST, total sleep time; AHI, apnoea-hypopnoea index; NREM, non-rapid eye movement sleep; REM, rapid eye movement sleep; Tcco2, transcutaneous carbon dioxide pressure.

  • *n = 13; †n = 15.