294 RANDOMIZED CONTROLLED TRIAL COMPARING ENDOSCOPIST-ADMINISTERED KETAMINE TO OPIOID/BENZODIAZEPINE MODERATE SEDATION FOR ADULT OUTPATIENT ENDOSCOPY

Ketamine, first used for procedural sedation in the 1960s, has made a resurgence, because it is an effective sedative agent in a variety of settings, due to its desirable cardiovascular properties including lack of effect on the laryngeal reflex. Although extensively used for pediatric endoscopic sedation, data regarding its use in adult populations is extremely limited. We hypothesized that ketamine is an effective alternative to standard moderate sedation regimens (SMS) and would be preferred by patients. Therefore, we designed a pilot study to compare ketamine to standard moderate sedation regimens. After obtaining Institutional Review Board approval, we conducted a randomized controlled trial comparing ketamine to SMS for outpatient colonoscopy or upper endoscopy at Brooke Army Medical Center from February 2018 to August 2019. The study was designed with a necessary enrollment of 66 patients to achieve a 0.5% unit change in satisfaction with a power of 0.8 and alpha of 0.05. After obtaining informed consent, subjects were randomized into either the ketamine group or SMS group. Those in the ketamine group received 1mg of midazolam along with ketamine, while the SMS group received standard midazolam/fentanyl. The primary outcome was patient satisfaction measured using the Patient Satisfaction in Sedation Instrument (PSSI) and secondary outcomes included changes in hemodynamics, time to sedation onset and recovery, and total doses of medications. A total of 66 subjects were enrolled; 33 in each group. Baseline variables including age, gender distribution, ASA scores, and types of procedures performed were similar (Table 1). Colonoscopies and upper endoscopies were performed for both diagnostic and screening purposes. Patients in the ketamine group were significantly more satisfied with their overall sedation experience and in all analyzed subcategories including sedation delivery, procedural recall, and side effects, compared to the SMS group (p=0.0096). The median time to onset of sedation and overall procedure time was faster in the ketamine group compared to the control group. The median dose of ketamine was 75mg and median doses of fentanyl and midazolam in the control group were 150mcg and 5mg respectively. Vital signs remained significantly closer to physiological baseline in the ketamine group (p=0.004). Recovery times were no different between the groups and no emergence reactions or hallucinations were reported (Table 2). Ketamine is preferred by patients, preserves hemodynamics better than SMS, and can be safely administered by endoscopists. Ketamine has the potential to greatly enhance sedation in many settings, including those with baseline abnormal hemodynamics, as well as for difficult to sedate patients. Use of ketamine will likely require education about its benefits.View Large Image Figure ViewerDownload Hi-res image Download (PPT)