AAO-HNSF Primary Care Otolaryngology Handbook

8

CHAPTER 1

Drug-Induced Sleep Endoscopy A contemporary diagnostic measure for evaluating OSA is the use of drug-induced sleep endoscopy (DISE) . In the United States, this proce- dure is primarily performed by otolaryngologists. While PSG and HST are used to establish a diagnosis of OSA, DISE is used as a tool to examine the structure and pathophysiology of the patient’s upper airway during obstructive events. Thought about even simpler, a PSG or HST reveals if a patient has OSA and the severity of the disease, while a DISE attempts to answer why a patient has OSA from an anatomic standpoint. The goal of DISE is to achieve a dynamic upper airway exam in an asleep patient, with the intention of triggering episodes of collapse to formally evaluate the location and severity of collapse and guide surgical decision making. It can be used as a stand-alone procedure or adjunct at the time of surgery, and is typically performed in a procedure suite or operating room. Originated in Europe in the 1990s, DISE includes three key features: • Use of a pharmacologic agent to achieve sedation • Sedation targeted to a depth to approximate sleep with spontaneous ventilation • Endoscopic evaluation of the upper airway—usually using a flexible laryngoscope Multiple classification and scoring schemes have been designed and published. A common scoring method is the VOTE classification , in which the degree of airway collapse is scored at the following levels: • V—Velum

110

• O—Oropharynx • T—Tongue base • E—Epiglottis

Each level is scored as 0 (no collapse), 1+ (partial collapse), or 2+ (complete collapse). Further designation can be given to the geometric configuration of the collapse. One example would include palate (velum)-level collapse as being either anteroposterior or circumferential. Patients being considered for candidacy for hypoglossal nerve stimulation all require a preoperative DISE exam. Complete (2+) circumferential collapse at the velum is considered a contraindication for the procedure.

Primary Care Otolaryngology