A Study to Assess Sedation Using Intranasal Dexmedetomidine in Upper Gastrointestinal Endoscopy

Upper gastrointestinal endoscopy, like many other diagnostic and therapeutic procedures, may be associated with discomfort. Although upper endoscopy is usually of shorter duration and better tolerated by patients, most trials investigating the influence of analgesia and sedation have been performed on patients undergoing this procedure. Some patients may tolerate colonoscopy without sedation, but various techniques are used to limit discomfort and pain. Selection and dosing of sedatives depends on the patient's emotional state, the intensity of pain during examination, foreseeable technical difficulties, the endoscopist's experience, the presence or absence of anesthesia personnel, and hospital-specific procedures.

Conscious sedation is a popular technique for colonoscopy and upper gastrointestinal endoscopy. The combination of an opioid and a benzodiazepine is known to provide good analgesic and sedative conditions during endoscopy. This combination of opioid and benzodiazepine, however, also increases the risk of respiratory depression. Therefore, pharmacologic agents which may provide adequate sedation without respiratory depression are of great interest to clinicians.

Dexmedetomidine is a highly selective α2-adrenoceptor agonist with sedative and analgesic effects. Compared with clonidine, it is more selective for the α 2 adrenoceptor and acts as a full agonist in most pharmacologic test models. Potentially desirable properties include decreased requirements for other anesthetics and analgesics, a diminished sympathetic response to stress and the potential for cardioprotective effects against myocardial ischemia. When compared with conventional sedatives such as opioids or benzodiazepines, its lack of respiration depression is a distinct advantage. Previous studies using dexmedetomidine for sedation has been promising with maintenance of respiratory function. Patients are readily arousable. With intravenous slow bolus administration, there is a minimal increase in blood pressure initially, followed by a slight decrease in blood pressure. Lower dose ranges, avoidance of rapid bolus injection, and a slow rate of administration tend to decrease these circulatory side effects. Many clinical studies have shown that it can be well and safely used intravenously, intramuscularly and transdermally. Although not an officially technique, there are also reports of intranasal administration resulting in fairly predictable onset in both adults and children.