We will be investigating the use of ketamine in sedation for endoscopic procedures, specifically outpatient endoscopy including esophagoduodenoscopy (EGD) and colonoscopy. Participants will be randomized to one of two arms including conventional moderate sedation with midazolam and fentanyl or the ketamine arm. They will then undergo the planned procedure. Physicians preforming the procedure will be surveyed following the procedure and patients will be surveyed twice, once after meeting criteria for discharge on day of the procedure and a second time 48 hours following the procedure.

In this study, the investigators plan to conduct a single blinded randomized controlled trial in the Gastroenterology Service to demonstrate the efficacy of ketamine and its utility in moderate sedation. Patients presenting to the endoscopy lab for esophagogastroduodenoscopy (EGD) and/or colonoscopy who meet inclusion criteria will be approached, and if amenable, will be consented and enrolled. Patients will be randomized to receive either a ketamine loading dose and then subsequent doses IV ketamine and midazolam 1mg IV prior to administration of ketamine or standard fentanyl/midazolam moderate sedation during their procedure. Participants will then undergo the planned procedure. The primary outcome will be patient satisfaction, which will be measured using the validated "Patient Satisfaction with Sedation" instrument (PSSI). A number of secondary outcomes will include the following: (1) provider satisfaction (measured using and the "Clinician Satisfaction with Sedation" instrument (CSSI), (2) the time from sedation administration to procedure start (when the scope is inserted), (3) the time from sedation to recovery (defined as the time from the end of the procedure until the patient meets discharge criteria from the recovery area), (4) time to cecum (for colonoscopy) total doses of medications given (midazolam, fentanyl, and ketamine), (5) overall time of the procedure, (6) adverse events, (7) changes in vital signs, (8) and the need for additional medications, in particular reversal agents.

Inclusion Criteria:

• Patients age 18 to 65 years who present to the GI clinic for an EGD or colonoscopy

Exclusion Criteria:

• Poor vital sign stability

• Hypoxia: O2 < 92%,

• Hypotension, hypertension, heart rate and respiratory rates greater than 20% above or below normal as dictated by normal ranges in SAMMC protocol

• Any allergy to ketamine, fentanyl, or midazolam

• Patient is pregnant or refuses pregnancy test, in women of child-bearing potential.*

• American Society of Anesthesiologists (ASA) score>3

• Presence of a history of psychosis, hallucinations, and/or a psychotic disorder

• History of increased intracranial pressure/ hypertensive hydrocephalus within the last 3 months

• Active pulmonary infection or disease.

• History of airway instability, tracheal surgery, or tracheal stenosis.

  • * Not applicable if patient is a female over 50 years old or has had a hysterectomy and/or oophorectomy