Variation in the duration of arousal in obstructive sleep apnea.
BACKGROUND
The aim of this study was to evaluate the relationship between the duration of arousal and the type, duration and minSaO(2) of apneas/hypopneas, and the time of night and sleep stage when they occurred.


METHODS
We measured the duration of arousals associated with apneas (A) and hypopneas (H) in 10 polysomnographic recording. Arousals were categorized as: 1) Short Electroencephalographic Arousal (SEA: 3-15 s) and 2) Awakenings (>15 s). The dependent variable for multiple logistic regression analysis was duration of arousal (0 = 3-11 s, 1 = >11 s); the independent variables were event (0 = H, 1 = A), event duration (0 = 10-20 s, 1 = >20 s), sleep stage (0 = REM, 1 = NREM 1-2); minSaO(2) (0 = 86%, 1 = <86%) and time of night (0 = at or before 3:00 AM, 1 = after 3:00 AM).


RESULTS
We analyzed 1536 apneas and hypopneas. 80.3% had arousal, 61% SEA and 19.3% awakenings. The median duration of arousal was higher in apneas (A: 12 s, H: 9.2 s, p<0.001). The apneas and events >20 s with a minSaO(2) <86% had a higher probability of arousal >11 s (apnea: OR 2.1, p<0.001; events >20 s: OR 1.5, p<0.01; minSaO(2) <86%: OR 1.4, p<0.05).


CONCLUSIONS
Arousals were greater in apneas than in hypopneas. Apneas and events >20 s with a minSaO(2) <86% were associated more frequently with arousal >11 s.
Nigro
Carlos Alberto
CA
Sleep Laboratory, Hospital Alemán, Buenos Aires, Argentina. cnigro@intramed.net
Rhodius
Edgardo Edmundo
EE
D001143:Arousal; D004569:Electroencephalography; D006801:Humans; D017286:Polysomnography; D012044:Regression Analysis; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000503:physiopathology*; D012894:Sleep Stages / Q000502:physiology; D013997:Time Factors; D014851:Wakefulness / Q000502:physiology