Upper Airway Collapsibility Evaluation in Different Sedative Levels by Sleep Endoscopy

Overview

The purpose of this study is to evaluate the upper airway collapsibility by sleep endoscopy in different sedative levels. Propofol pump infusion will be used to achieve conscious sedation. Bispectral Index monitor will be applied to the monitor the conscious level. Two different sedative levels (BIS 65-75, 50-60) will be achieved for upper airway evaluation. The severities of upper airway obstruction will be evaluated the correlation to the disease severities. Mandible advancement will be done to evaluate the response for oral appliance.

Obstructive sleep apnea/hypopnea syndrome (OSAHS) is a disorder characterized by recurrent upper airway collapse during sleep. Clinical consequences as increased cardiovascular events and automobile accidents were noted. Polysomnography is diagnostic while continuous positive airway pressure (CPAP) is the standard treatment. The adherence of CPAP treatment remained suboptimal, between 29 to 83%. In selected cases, alternative treatments were considered useful. However, how to choose candidates is still an issue. Sleep endoscopy has been introduced since 1991 to allow direct visualization of the upper airway under sleep simulation. It predicts better outcome in non-adherent OSAHS patients who received alternative treatment. However, the ideal dose, drug, and sedative depth were not known. Bispectral Index (BIS) monitor is a noninvasive neurophysiological monitoring device that been introduced since late 1990's. By applying a sensor to the forehead, the BIS obtained electroencephalograms(EEG) and electromyograms(EMG) which were transformed into simplified scaled numbers through 0-100. It has been applied in the real time monitor of anesthesia depth during operation or recovery, monitor of sleep in critical illness patients and gastrointestinal endoscopy sedation. This study focuses on CPAP non-adherent patients. It evaluates the upper airway collapsibility in awake and two different sedative levels, BIS 65-75 (light sedation) and BIS 50-60(deep sedation). Conscious sedation will be achieved by propofol pump infusion. No benzodiazepam or opioid are used to avoid the effect of upper airway muscle tone and respiratory drive. The patency over the velopharynx, oropharynx, larynx, and hypopharynx will be recorded. Specific obstruction patterns such as tongue base retraction, epiglottis anterior-posterior decent, omega-shaped epiglottis,and bilateral arytenoids anterior drawing will also be recorded. The correlation of the upper airway collapsibility between sedative depth and sleep stages (ex. NREM vs. REM) will be evaluated. Besides, mandible advancement will be done under deep sedation. The response will guide further treatment choice for those CPAP non-adherent patient.