The Effects of Different Loading Doses of Dexmedetomidine on The Bispectral Index-Guided Propofol Sedation in Patients Undergoing Advanced Upper Gastrointestinal Endoscopic Procedures: A Randomized Control Study

Advanced upper gastrointestinal tract procedures such as Endoscopic retrograde cholangiopancreatography (ERCP) & Endoscopic ultrasound (EUS) are very important diagnostic and therapeutic procedures for the diagnosis & management of many pancreatobiliary pathologies whether benign or malignant (1-4). These procedures require moderate-deep sedation with the patient lying in the lateral or semi-prone position to provide the operator easier access & insertion while permitting fluoroscopic visualisation (1-4).

Propofol sedation is currently the most popular drug used for advanced endoscopic procedures because of its shorter half-life which results in a shorter recovery time than conventional sedation (benzodiazepine &/or opioid) (5). Propofol was administered initially by intermittent boluses but later on was superseded by continuous infusion guided by clinical scoring, e.g., Ramsey sedation score (6), by target-controlled infusion (TCI) (7) or more recently by bispectral index (BIS) monitoring (8).

Propofol, however, has a narrow therapeutic window that may cause fluctuation of the level of sedation from moderately deep sedation to near general anesthesia. Not only that but also propofol sedation is associated with many other complications including apnoea, airway obstruction desaturation, hypotension, bradycardia, gagging, restlessness, regurgitation & vomiting & delayed recovery (9).

Dexmedetomidine, a highly specific, potent and selective α2-adrenoceptor agonist, was originally introduced as a sedative for critically ill mechanically ventilated patients [9]. In addition to sedation, it has a group of unique properties in the form of analgesia, reduction of sympathetic tone and attenuation of the neuroendocrine and hemodynamic responses to anesthesia and surgery with minimal respiratory depression, making it an attractive agent for perioperative sedation especially in remote areas outside the operating theatres (6,10).

The quest to replace propofol coupled with the unique sedo-analgesic properties of dexmedetomidine resulted in the interest in the use of dexmedetomidine for providing sedation for advanced endoscopic procedure (6,10).