[Occurrence of complex sleep apnea during continuous positive airway pressure therapy]

To explore the occurrence of complex sleep apnea syndrome in patients with obstructive sleep apnea during continuous positive airway pressure titration and evaluate their polysomnographic characteristics.

A total of 420 patients with obstructive sleep apnea were recruited to undergo an overnight continuous positive airway pressure titration at the Sleep Medicine Center, West China Hospital from January 2010 to December 2012. Their polysomnographic records of respiratory events, oxygen desaturation events and sleep stages were retrospectively reviewed.

The incidence of complex sleep apnea syndrome was 7.9% (33/420) and central apnea index (9.0 ± 5.1) /h.No significant differences existed in age, gender, body mass index and titration pressure of continuous positive airway pressure between two groups. Compared with those with non-complex sleep apnea, complex sleep apnea patients had significant increases in apnea/hypopnea index (12.8/h vs 3.6/h, P < 0.05) and oxygen desaturation index (10.3/h vs 3.8/h, P < 0.05) which mainly happened in non-rapid eye movement stage. They also showed decreases in total sleep time ((365 ± 96) vs (402 ± 77) min), rapid eye movement stage (16% ± 8% vs 20% ± 10%) , increases in non-rapid eye movement stage 1 (24% ± 17% vs 15% ± 13%), wakefulness after sleep onset ((108 ± 93) vs (79 ± 61) min) and brief arousal index ((28 ± 15) vs (20 ± 12)/h). And the differences were statistically significant (all P < 0.05).

Complex sleep apnea syndrome is common among Chinese patients with obstructive sleep apnea. Compared with those with non-complex sleep apnea, complex sleep apnea patients have reduced sleep time and worse sleep quality during continuous positive airway pressure therapy.