Determination of the median effective dose of propofol in combination with different doses of ketamine during gastro-duodenoscopy in children: a randomised controlled trial.

Background: Propofol is used to induce deep sedation or general anaesthesia for procedures in children. Adjuvants, such as ketamine, are routinely added to reduce the dose of propofol required and propofol-related adverse events. We conducted a randomised controlled trial to determine the effective bolus dose of propofol in combination with ketamine that induces adequate depth of anaesthesia in 50% of children (ED) undergoing gastro-duodenoscopy.

Methods: Children were randomised to one of four doses of ketamine: 0 (control), 0.25, 0.5, and 1 mg kg, followed by a dose of propofol according to Dixon's up-and-down methodology. Excessive movement, coughing, gagging, or airway obstruction that prevented endoscope insertion was considered a failure.

Results: The ED of propofol (median, 95% CI) was greater in the ketamine 0, 0.25, and 0.5 mg kg groups compared with the ketamine 1 mg kg group (6.1, 4.1-8.1; 4.5, 2.9-6; 4.7, 3.1-6.2 mg kgvs 1.1, 0.5-1.8 mg kg, respectively, P<0.008). Total dose of propofol administered during the procedure was reduced with ketamine 1 mg kg. The mean arterial pressure was lower in the ketamine 0 mg kg group compared with the 1 mg kg group during and immediately after the procedure. The ketamine 1 mg kg group experienced a higher incidence of nausea and visual disturbances.

Conclusions: Ketamine at 0.5-1 mg kg reduces the dose of propofol required to provide general anaesthesia for gastro-duodenoscopy in children and may reduce the incidence of propofol-related changes in haemodynamics.

Clinical Trial Registration: NCT 02295553.