Preemptive Low-dose Epidural Ketamine for Preventing Chronic Postthoracotomy Pain

OBJECTIVES: Chronic postthoracotomy pain is the most common long-term complication that occurs after a thoracotomy with a reported incidence of up to 80%. Although thoracic epidural analgesia is a widely used method for managing acute postthoracotomy pain, its effects seems questionable. The objective of this prospective, double-blinded, randomized, controlled trial was to assess the effect of preemptive low-dose epidural ketamine in addition to preemptive thoracic epidural analgesia on the incidence of chronic postthoracotomy pain. METHODS: We analyzed 133 patients who were randomized to preemptive thoracic epidural analgesia either with or without ketamine (Group K: 0.12% levobupivacaine, 2 μg/mL of fentanyl, 0.2 mg/mL ketamine, total volume of 500 mL vs. Group KF: 0.12% levobupivacaine, 2 μg/mL of fentanyl, total volume of 500 mL). Pain at the thoracotomy scar site during rest and movement (coughing) was assessed at 2 weeks and 3 months after surgery using a visual analog scale. The incidence of allodynia and numbness was also evaluated. RESULTS: There was no difference in the incidence of chronic postthoracotomy pain at 3 months between the 2 groups (67.7% in group K vs. 75% in group KF). The incidences of allodynia or numbness were not different between the 2 groups. DISCUSSION: The addition of preemptive low-dose epidural ketamine (1.2 mg/h) to preemptive thoracic epidural analgesia did not have any beneficial effects in preventing chronic postthoracotomy pain.