This is a study evaluating the usage of Ketamine as sedative agent in ERCP. The usage of Ketamine will be compared to the standard sedation in our center, which is Midazolam in combination with Pethidine as analgesia.

This is a double blinded study whereby both the surgeons and patients are blinded from the sedative agent used. Patients admitted to UKMMC requiring ERCP will randomized into 2 groups after evaluating the inclusion and exclusion criteria. Patients will be divided into two arms, Midazolam and Ketamine group respectively. Before the initiation of the the scope, patient would be given specified dose of sedation accordingly. All the parameters and outcome would be measured during and after the procedure.

Inclusion Criteria:

• Malaysian citizens of who is able to give valid consent
• Patient planned for ERCP (either emergency or elective)

Exclusion Criteria:

• Known hypersensitivity towards Ketamine or Midazolam
• Patient refusal to participate or unable to give consent
• Increased intracranial pressure, acute stroke (<3 months), intracranial haemorrhage (<3 months)
• Uncontrolled hypertension (BP>160/100) and tachycardia (Heart rate >120)
• Acute myocardial infarction, acute coronary syndrome (<3 months)
• Tachyarrythmia
• Pregnancy
• IVDU or substance abuse patient
• Patient with history of hallucination
• Child's Pugh Class C

Both the patients and surgeon will be blinded from knowing the sedative agent