We evaluated an auto-nasal continuous positive airway pressure (nCPAP)
prototype (MC+; SEFAM, Nancy, France) in which apnoea/hypopnoea detec
tion was disabled and nasal mask pressure vibration detection was the
only mode of pressure setting, The device was tested in 15 previously
untreated obstructive sleep apnoea patients during a night with polyso
mnography. We observed that a single night of auto-nCPAP improved the
apnoea/hypnoea index (AHI) (12+/-21 vs 51+/-31 disordered breathing ev
ents . h(-1) of sleep (mean+/-SD)), the awakening-arousal index (13+/-
20 vs 40+/-26 arousals . h(-1) of sleep), and duration of slow wave sl
eep (102+/-49 vs 71+/-56 min) but not of rapid eye movement (REM) slee
p (55+/-31 vs 64+/-38 min), Auto-nCPAP was effective (apnoea/hypopnoea
and arousal indices <10 events . h(-1)) in all but three patients. Au
to-nCPAP was ineffective in one patient, whose obstructive respiratory
events were not preceded by nasal mask pressure vibration detection,
and in two patients who were quasi-permanent mouth breathers. Snoring
detection may be effective in sleep apnoea syndrome with heavy snoring
and without permanent mouth breathing, during the first night of nasa
l continuous positive airway pressure treatment.