Abstract
Excessive daytime sleepiness (EDS) is the obstructive sleep
apnea syndrome (OSAS) most frequent symptom. The relationship
between the level of daytime sleepiness and standard
polysomnographic variables (i.e., apnea/hypopnea index [AHI] and
oxygen saturation SaO2) has been the subject of a number of
studies. To date, the results have been inconsistent. The goal
of this study is to assess the variables significantly related
with daytime sleepiness severity. The variables chosen were: AHI,
percentage of total time that the subject remains with arterial
oxygen saturation level below 90% (SaO2<90%), minimum oxygen
saturation (SaO2 m), body mass index (BMI), and age. The study
sample was composed of 51 obstructive sleep apnea patients
selected from a medical centre.
Subjects completed using the Epworth Sleepiness
Scale (ESS) to determine daytime sleepiness. The OSAS was
diagnosed by conventional polysomnography.
The results indicated significant correlations
between level of daytime sleepiness and age (r=.302; p<.05), BMI
(r=.339, p<.05), SaO2 m (r=-.393, p<.01) and SaO2 < 90% (r=.492,
p<.01). Significant correlations were also found between AHI and
SaO2<90% (r=.314, p<.05), BMI and SaO2<90% (r=.387; p<.05), and
SaO2 m and SaO2<90% (r=- .746; p<. 01). No significant
correlation was detected between AHI and level of daytime
sleepiness. According to the results, the percentage of total
time that the subject remains with arterial oxygen saturation
level below 90% (SaO2< 90%) is the best predictor of daytime
sleepiness severity.
