Background and Goal of Study: Adequate patient sedation for ambulatory colonoscopies should include amnesia, sedation, analgesia with haemodynamic stability and minimal adverse effects. We examined the potential beneficial effect of low dose ketamine on Midazolam-Fentanil-Propofol based sedoanalgesia for outpatient colonoscopy.
Materials and Methods: One hundred patients undergoing colonoscopy with sedoanalgesia were randomly assigned to two groups of 50 patients each in a double-blinded fashion. Patients received midazolam (0.02 mg/kg), fentanyl (1 μg/kg), ketamine (0.3 mg/kg) and midazolam (0.02 mg/kg), fentanyl (1 μg/ kg), placebo (%0.9 NaCl) in Group C+K and Group C respectively. In both groups incremental doses of propofol used in order to have a Ramsay sedation score of 3-4. Values of heart rate, blood pressures, oxygen saturation, respiratory rate and Ramsay sedation scores were recorded every 2 min for the first 10 min and every 5 min thereafter, until the completion of the procedure. Procedure times, recovery times, drug doses used, complications associated with the sedation, physician and patient satisfaction during and after colonoscopy were also recorded. Student T test and χ2 test were used for data analysis with SPSS.
Results and Discussion: A total of 97 patients were included in this study. Mean systolic blood pressures at 4, 6, 8, 10 min (p< 0.01) and diastolic blood pressures at 4, 6, 8 min (p< 0.01), mean respiratory rates at 4, 6, 8, 10, 15, 20, 25 min (p< 0.01), and mean SpO2 at 6, 8, 10, 15 and 20 min (p< 0.05) were lower in Group C compared with Group C+K. Induction time (p< 0.0001), the amount of propofol used (p< 0.0001), the use of mask ventilation (p< 0.05), the incidence of disruptive movements (p< 0.005) were significantly lower and physician satisfaction at the begining of the procedure (p< 0.05) was superior in Group C+K. Recovery times and patient satisfaction were similar. No unpleasent dream or hallucinations were reported.
Conclusion(s): Low dose ketamine is a useful adjunct to conscious sedation in patients undergoing colonoscopy. It's addition, results in better quality and depth of sedation, more stable haemodynamics, less propofol consumption and less adverse effects with similar recovery times in patients sedated using Midazolam-Fentanil-Propofol based sedation.