"Light" Versus "Deep" Bispectral Index (BIS) Guided Sedation for Colonoscopy

A Randomised Controlled Trial of "Light" Versus "Deep" Sedation for Elective Outpatient Colonoscopy: Recall, Procedural Conditions and Recovery

In this trial, patients undergoing elective colonoscopy under sedation will be randomised to BIS-guided sedation targeting either "light" (bispectral index [BIS] 70-80) or "deep" (BIS<60) sedation. Sedation will be achieved with a standardised regimen of target-controlled infusion of propofol and fentanyl bolus. The primary end point will be the incidence of procedure recall in each group - this will be assessed at the conclusion of the procedure. The procedural conditions, cardio-respiratory complications and recovery including cognitive function will be assessed during and immediately after the procedure. The incidence of dreaming and patient satisfaction with anaesthesia care will be recorded immediately after the procedure. The study will be complete when the patient leaves the hospital on the day of the procedure.

Controversy exists about the need for deep sedation or light sedation during elective colonoscopy. Deep sedation ensures amnesia for the procedure and may ensure better operating conditions, but may result in cardiorespiratory side effects and prolonged recovery. Differences exist between countries regarding the prevailing depth of sedation with deeper sedation in general being administered in Australia than the United States. This study aims to explore that controversy.

Inclusion Criteria:

• Plan for elective outpatient colonoscopy under sedation
• Able and willing to provide written informed consent for study entry and completion of all study related procedures
• American Society of Anesthesiologists' (ASA) physical status grade 1-3

Exclusion Criteria:

• Colonoscopy and gastroscopy booked as joint procedures
• Colonoscopy on emergency patients and/or inpatients
• Inadequate English comprehension (verbal and written to understand the Participant Information and Consent Form)
• Intellectual or psychiatric disability that prevents consent to and comprehension of study procedures
• Significant cognitive impairment that prevents independent conduct of activities of daily living or results in 3rd party procedural consent being obtained
• ASA physical status grade 4-5