Reduction Of Chronic Post-surgical Pain with Ketamine – A Pilot Study

INTERVENTION: The effect of intravenous ketamine given prior to and for up to 24 hours following surgical incision on the prevalence and severity of chronic post‐surgical pain at 4‐6 months postoperatively. Ketamine dosage is 0. 5mg/kg bolus, followed by 0.25 mg/kg/hr intra‐operatively. then 0.1 mg/kg/hr continued for 24 hour CONDITION: Chronic post‐surgical pain PRIMARY OUTCOME: The incidence of chronic post‐surgical wound‐related pain reported by the patient using a structured questionnaire incorporating the modified brief pain inventory (mBPI). SECONDARY OUTCOME: Opioid and other analgesic consumption Quality of life estimates using the WHODAS and Kessler K‐10 Depression scale, and their relationship to pain prevalence and severity The mean severity of chronic post‐surgical wound‐related pain measured using a Visual Analog Scale (0‐100). The relationship of the severity of acute postoperative pain to chronic post surgical pain prevalence and severity using a Visual Analog Scale (0‐100). The severity of acute postoperative pain measured using a Visual Analog Scale (0‐100). INCLUSION CRITERIA: Patients undergoing elective abdominal or non‐cardiac thoracic surgery under general anaesthesia involving a skin incision at least 8 cm in length and a hospital stay of at least one night postoperatively.