Reduction Of Chronic Post-surgical Pain with Ketamine - ROCKet Trial

The effect of intravenous ketamine administered prior to and for up to 72 hours following surgical incision on the incidence of chronic post-surgical pain at 12 months post-operatively. Ketamine or placebo dosage is intravenous 0.5 mg/kg bolus, followed by 0.125 mg/kg/hr intra-operatively, then 0.125 mg/kg/hr continued for up to 72 hours post-operatively. The initial bolus dose will be administered after induction and prior to surgical incision. The trial infusion will be continued for 72 hours after the commencement of surgery, or until: 1. the patient no longer requires opioid analgesia (IV or oral) for acute pain management, or 2. IV access is discontinued by the treating surgical unit, or 3. the patient is deemed ready for discharge home by the treating surgical unit. The research staff will liaise daily with the treating ward staff and acute pain service to coordinate trial solution administration with the patient care plan for each day. Trial solution rate dose escalation: In the case of severe postoperative pain that is not responding adequately to standard postoperative analgesia (NRS or VAS pain score >5/10 with functional impairment of postoperative mobilization), the trial solution infusion rate can be doubled to 0.25 mg/kg/hr (ketamine or placebo equivalent) by the treating acute pain team. This should be reviewed daily and returned to the standard rate where pain control becomes satisfactory or if side effects which are considered possibly related to the study drug are found to be dose limiting. Trial solution rate dose reduction: If the patient is experiencing symptoms such as hallucinations, unpleasant dreams, delirium, confusion or drowsiness which the research staff in consultation with the treating clinicians suspect may be due to ketamine administration and which are causing distress or impeding patient’s postoperative mobilisation or recovery, the trial solution can be ceased for 2 hours and re-commenced at half the rate administered previously. Trial solution cessation: Following dose reduction of >6 hours, if there are persisting postoperative symptoms such as hallucinations, unpleasant dreams, delirium, confusion or drowsiness which the research staff in consultation with the treating clinicians suspect may be due to ketamine administration and which are causing distress or impeding patient’s postoperative mobilisation or recovery, the trial solution can be ceased Dose escalation, reduction or cessation will be captured in the eCRF and be centrally monitored via the database. Site monitoring will occur early in the trial and allow for education of research staff. 1. If the trial solution is stopped or is interrupted for whatever reason by clinical staff, and upon review it is considered that the trial solution should be recommenced, this can occur. 2. Trial solution rate dose escalation: This should be reviewed at least daily, or more urgently or frequently if required, for example due to refractory severe pain or suspected side effects.