Impact of microarousal associated with increased negative esophageal pressure in sleep-disordered breathing.

PURPOSE

"Microarousals" during sleep have not been analyzed systematically. We investigated the importance of "microarousals" (lasting 1.5-3 s).

METHODS

Standard polysomnography including esophageal pressure (Pes) assessment was performed on ten patients (aged 54.0 +/- 5.0 years) with respiratory effort-related arousal > or =5/h. We measured the number of arousals per hour (American Sleep Disorders Association (ASDA) arousal index) and the number of microarousals lasting 1.5-3 s per hour (mASDA arousal index). On the night after the baseline sleep study, we performed overnight continuous positive airway pressure (CPAP) titration.

RESULTS

mASDA arousals, characterized by lower Pes values, were observed more frequently in patients with sleep-disordered breathing. The Pes results did not differ significantly between ASDA and mASDA arousals (-15.6 +/- -5.0 vs -15.0 +/- -4.4 cmH(2)O). mASDA arousals were significantly improved by CPAP treatment (mASDA arousals, 82.6 +/- 60.1 vs 6.0 +/- 1.4/h).

CONCLUSIONS

mASDA arousals were characterized by an increase in Pes. mASDA arousals are thus key to our understanding of clinical manifestations in patients with sleep-disordered breathing.