Comparison of intravenous tramadol and ketamine for prevention of catheter-related bladder discomfort after laparoscopic surgery: A randomized, placebo-controlled, double-blind study

Abstract

Objectives: To compare the efficacy of intravenous tramadol and ketamine for prevention of catheter-related bladder discomfort (CRBD) after elective laparoscopic surgery. Design: Randomized, placebo-controlled, double-blind trial Setting: King Chulalongkorn Memorial Hospital; a tertiary care center Research methodology: A total of 210 patients, aged 18-70 years with American Society of Anesthesiologists physical status I or II undergoing elective laparoscopic surgery requiring bladder catheterization were randomly allocated into one of three groups. Group T received intravenous tramadol 1.5 mg/kg, Group K received intravenous ketamine 0.5 mg/kg and Group P received intravenous saline as a placebo before catheterization. Patients received intermittent intravenous morphine for postoperative pain control. An anesthesiologist unaware of the randomiation status evaluated catheter-related bladder discomfort, postoperative pain and shoulder pain using visual analog scales (VAS) 0, 1, 2, 6 and 24 hours after surgery. Postoperative 24-hour morphine requirement and adverse effects were also assessed. Results: Patients in Group T and K had significantly lower CRBD severity compared with control 6 hours (mean±SD of tramadol=4.9±12.12 versus placebo=12.4±22.7; p=0.04, ketamine=3.5±13.2 versus placebo=12.4±22.7; P=0.002) and 24 hours after surgery (tramadol=3.2±9.6 versus placebo=9.2±18.7; p=0.028, ketamine=1.3±4.3 versus placebo=9.2±18.7; P=0.002). Postoperative pain severity, total 24-hour morphine consumption and adverse events including sedation, postoperative nausea and vomiting, blurred vision, respiratory depression, hallucinations and hemodynamic instability were broadly comparable between the groups. Patients in Group T had a significantly lower incidence of shoulder pain (7 out of 67 patients [10.4%]) than those in Group K (21 out of 70 [30%]) and control (24 out of 70 [34.3%]) 24 hour after surgery (P=0.006 and 0.001, respectively). Conclusions: Intravenous tramadol 1.5 mg/kg and ketamine 0.5 mg/kg administered before bladder catheterization are both effective in reducing the severity of postoperative CRBD 6 and 24 hours after elective laparoscopic surgery without significant adverse effects. Tramadol also decreases the incidence of post-laparoscopy shoulder pain.