Natural Sleep and Drug-induced Sleep Endoscopy

Drug induced sleep endoscopy (DISE) has been performed worldwide since 1991 to determine the site and configuration of upper airway obstruction in patients with obstructive sleep apnea. However, there are no studies comparing DISE to sleep endoscopy during natural sleep. Objective: to compare natural sleep endoscopy to drug induced sleep with propofol.

The study population will include 28 patients who are candidates to surgical treatment.

Methods Detailed clinical history and physical examination will be performed before natural sleep endoscopy. A 2-hour fast will be required. During both natural sleep and propofol-induced sleep, pharyngeal pressure will be measured using a pressure-tipped catheter (model TC-500XG; Millar).The nasopharynx will be numbed with xylocaine (10%) and oxymetazoline (0.05%), the catheter will be passed through a nasal mask into one nostril, and placed at the tongue base as confirmed by visual inspection of the oropharynx.A 2.8mm pediatric bronchoscope (Olympus) will be passed through the mask and into the other nostril. A nasal mask will be fitted and a heated pneumotachograph with differential pressure transducer connected to the mask will quantify airflow. The endoscope will be located at velopharynx, lateral wall of the pharynx and 2 cm above tongue and epiglottis.The VOTE Endoscopic Classification will be used to describe site and configuration of pharyngeal collapse in each study. The study will be scored by two experienced investigators, blind to the patient identification and type of study (natural sleep or drug-induced). Propofol-induced sleep will be performed at the operating room before surgery.

Inclusion criteria

• BMI less than 35kg/m2
• Apnea-hypopnea index > 5 events/hour of sleep
• Clinical indication of surgical treatment for sleep apnea

Exclusion criteria

• Severe or decompensated cardiac or respiratory diseases
• Previous pharyngeal surgery
• Tonsils grade III or IV
• Other sleep disturbance (parasomnias, primary insomnia, narcolepsy)
• Sedative medication use (opioids, benzodiazepines and muscle relaxants)
• Uncontrolled diabetes or hyperthyroidism