Effect of Palatable Lidocaine Gel Versus Dexmedetomidine on Gag Reflex During Propofol Based Sedation for Patients Undergoing Elective Upper Gastrointestinal Endoscopy. A Randomized Controlled Study

Upper gastrointestinal tract endoscopy (UGIE) is a valuable procedure that is commonly used for the diagnosis of possible causes of upper gastrointestinal tract (GIT) symptoms such as bleeding, pain, dysphagia, recurrent vomiting and reflux. Moreover, it is a safe and easy procedure for taking biopsy samples for suspected esophageal, gastric and duodenal diseases, grading and even ligating varices [1, 2].

UGIE is widely performed under propofol sedation that considered a safe sedation technique and alleviates the sympathetic response to the procedure. However, gag reflex and retching still exist in approximately 29% of those patients despite being under propofol sedation [3]. Any further trial of deepening sedation in order to minimize gagging may compromise hemodynamics and cause respiratory depression. These complications add to the overall costs as it increases morbidity and duration of patients' hospitalization. On the other hand, continued gag reflex could affect the safety of the procedure, patient's tolerance and endoscopist's satisfaction [4].

Dexmedetomidine, a short-acting selective α2-agonist, has been used frequently as a sedoanalgesic in many diagnostic and therapeutic procedures [5]. It provides unique sedative activity not present in conventional sedatives so it is unlikely to cause restlessness or respiratory depression was seen with Gaba aminobutyric acid (GABA) receptor agonists such as propofol. Therefore it minimizes physical and emotional distress and enhances successful completion of the procedure without remarkable gag reflex [6]. However, many clinicians may have qualms regarding the safety profile of dexmedetomidine usage in such endoscopic procedures due to its well known hemodynamic side effects (especially bradycardia and hypotension) [7].

Topical pharyngeal anesthesia(TPA) has been used to avoid such complications resulting from deepening sedation through increase i.v anesthetic doses of propofol or adjuvants that may be used as dexmedetomidine. TPA is preferred in many centers, particularly for diagnostic endoscopy [8, 9].

Lidocaine is widely used for TPA. The spray, gel and inhaler forms of it are commercially available. However, application of lidocaine gel to the oral cavity and the oropharynx, especially the base of the tongue, palate, uvula, palatopharyngeal, palatoglossal folds and posterior pharyngeal wall will attenuate or even abolish the gag reflex while introducing the UGIE, thus increasing the patient's comfort and tolerance to the procedure and decreasing the dose of i.v. anesthetics with their potential complications [10, 11].