Varadarajulu S et al. (2007) Prospective randomized trial evaluating ketamine for advanced endoscopic procedures in difficult to sedate patients. Aliment Pharmacol Ther 25: 987–997

Patients who undergo advanced endoscopic procedures must be adequately sedated; however, some patients are difficult to sedate and others react adversely to standard sedatives.

Varadarajulu et al. evaluated whether adding ketamine to a standard sedative regimen improved the sedation achieved by a standard sedative regimen alone. The study included 175 patients due to undergo endoscopic ultrasonography or endoscopic retrograde cholangiopancreatography who could not be adequately sedated by meperidine (50 mg), midazolam (5 mg) and diazepam (5 mg): 82 patients were randomly allocated to receive ketamine (20 mg every 5 min) and 93 patients to receive meperidine (25 mg) and diazepam (2.5 mg), until adequately sedated. The addition of ketamine to a standard sedative regimen had a significantly beneficial effect on sedation quality, patient discomfort and sedation-related technical difficulties (all three according to a qualitative physician's rating), as well as on depth of sedation, recovery time, sedation failure and standard sedative requirements. No significant differences were seen in sedation-associated complication rates for the two cohorts.

Despite the limitations of this study (e.g. nonblinded design, subjective outcome measures, patient satisfaction not assessed), the authors conclude that adding ketamine to a standard sedation regimen improves the quality and depth of sedation and reduces the recovery time for patients who are otherwise difficult to sedate. They now call for prospective, comparative, randomized, blinded trials to evaluate the safety and effectiveness of ketamine in patients undergoing either standard or advanced endoscopic procedures.