Objective: This study examines subjects' level of consciousness with bispectral analysis in sedation endoscopy of the upper airway.
Study design: A prospective study.
Setting: University hospital.
Subjects and methods: Bispectral analysis levels recorded in natural sleep of 43 patients with obstructive sleep apnea during an overnight polysomnographic sleep study were directly compared with the levels recorded during midazolam sedation sleep endoscopy in the same subjects. The possible muscle relaxation effect of midazolam was examined via surface chin electrodes. Supine Müller maneuver findings in 50 patients with obstructive sleep apnea were also compared with soft tissue dynamics during midazolam sedation sleep endoscopy.
Results: In our study of the 43 patients with bispectral analysis during natural sleep and midazolam sedation sleep endoscopy, a predominance of bispectral analysis values indicating N1 and N2 sleep was observed during the sedation study. Midazolam failed to achieve deeper levels of sleep with minimal N3 and no convincing rapid eye movement. As N1 and N2 are the stages during which maximal dynamic activities occur, and they make up an average of 70.5% of total sleep time, from 210 sleep studies at our laboratory, the present technique would be ideal as a surgical assessment tool. No muscle relaxation effect could be detected at our protocol dose of midazolam. The supine Müller maneuver findings were significantly different from those observed during sedation sleep.
Conclusion: These findings support the value of sleep endoscopy as an efficient and informative technique for the examination of upper airway dynamics relevant to focused surgical planning.