Comparison of efficacy of prophylactic ketamine and dexmedetomidine on postoperative bladder catheter-related discomfort.

Objectives: To compare the effects of prophylactic ketamine and dexmedetomidine on postoperative bladder catheter-related discomfort/pain in patients undergoing cystoscopy.

Methods: This prospective study was conducted on 75 American Society of Anesthesiologists (ASA) I-II patients between 18-75 years of age and undergoing cystoscopy between November 2011 and June 2012 at Hacettepe University Hospital, Ankara, Turkey. Patients were randomly assigned to one of the 3 groups to receive 1 μ/kg dexmedetomidine, 250 μ/kg intravenous ketamine, or normal saline. All patients were questioned regarding probe-related discomfort, patient satisfaction, and pain at the end of the operation 0 (t0) and 15 (t1), 60 (t2), 120 (t3), and 360 (t4) minutes postoperatively. Evaluations were performed in person at the  post-anesthesia care unit, or in ambulatory surgery rooms, or by phone calls.

Results: Pain incidence in the dexmedetomidine and ketamine groups (p=0.042) was significantly lower than that in the control group (p=0.044).The sedation scores recorded at t0 in the dexmedetomidine and ketamine groups (p=0.004) were significantly higher than that of the control group (p=0.017).Patient groups were similar regarding the rate of hallucinations experienced at t1, no patients experienced hallucinations at t2, t3, or t4. Significantly more patients experienced hallucinations at t0 in the ketamine group than in the dexmedetomidine group (p=0.034) and the control group (p=0.005). 

Conclusion: Dexmedetomidine and ketamine had similar analgesic effects in preventing catheter-related pain; however, dexmedetomidine had a more acceptable side effect profile. To identify the optimal doses of dexmedetomidine and ketamine, more large-scale interventional studies are needed.