Objective: To investigate polysomnographic determinants of excessive daytime sleepiness (EDS) and potential relationship in Chinese patients with obstructive sleep apnea-hypopnea syndrome (OSAS).
Methods: A total of 410 patients with obstructive sleep apnea-hypopnea syndrome were analyzed retrospectively who were obtained in Sleep medicine center of West China hospital from January to April in 2010. All of the patients with an apnea-hypopnea index (AHI) greater than 5 h(-1) were evaluated using the Epworth Sleepiness Scale (ESS) and sleep disorders questionnaire. The patients who ESS score was more than 10 were defined as EDS; otherwise, the other was considered to without EDS.
Results: A total of 176 patients with EDS (ESS: 15 ± 3) and 234 without EDS (ESS: 6 ± 3) were studied. Patients with EDS were slightly higher BMI (28 ± 4 vs 26 ± 4) and shorter REM sleep latency (99 ± 65 vs 125 ± 81) than patients without EDS. Furthermore, there were significant difference in awake SaO2, AHI, minimum SaO2, oxygen desaturation index and arousal index between EDS group were No-EDS group (P < 0.001). There was a significant difference in waking SaO2 of severe OSAS between both groups.
Conclusion: Long-term chronic hypoxia already exists in severe OSAS patients with prominent sleepiness. Waking SaO2 may play a role as a predictor in evaluation and diagnosis in patients with OSAS.