Endoscopic procedures like ERCP are performed with patient under moderate to deep sedation  

•Sedation reduces patient anxiety, discomfort and pain, enhancing patient cooperation and facilitating the procedure.

•Sedation during endoscopy also minimizes patient’s risk for physical injury during examination and provides the endoscopist with an ideal environment for  thorough examination.

Most patients undergoing ERCP may have obstructive jaundice, which makes them prone to hypotension and bradycardia during sedation.

•Sedation may be defined as a drug-induced depression in the level of consciousness.

•Four stages of sedation have been described, ranging from minimal (anxiolysis) to moderate , deep and general anesthesia.[1] The most common agent used for sedation is propofol as single use or in combination with other medications, because of better pharmacokinetic profile than benzodiazepines or opioids with regard to onset time and recovery time.[2,3] 

 â€¢Although propofol is routinely administered for GI endoscopy, it is associated with several adverse events such as hypoxia, hypotension, arrhythmia and risk of respiratory depression including apnea.[4,5] Etomidate is an  hypnotic agent with rapid onset (5-15 seconds) and recovery (5-15 minutes).[6]

•Etomidate has more stable cardiovascular profile than propofol [12] and minimal respiratory depression.

•Etomidate may causes minor side effects like pain on injection, postoperative nausea andvomiting (PONV), dose‑dependent myoclonus and adrenocortical suppression- gets normalised in 24 hrs. Bispectral index (BIS)[7] is considered a better indicator for depth of anesthesia compared to routine clinical parameters and results in decreased induction dose of anesthetic drug and quick recovery.

•It is a dimensionless number scaled between 0 and 100, with 100 representing awake patient and 0 represent absence of brain activity or electrical silence.

•An optimal value for the maintenance of sedation for endoscopic procedure should be between 60-70.

•Etomidate is mostly used as induction agent in anesthesia,very few studies done in ERCP using  Etomidate as sedative for loading and maintenance.