Efficacy of adding ketamine to levobupivacaine in paravertebral block on acute and chronic pain in thoracotomy: a randomized controlled double-blinded trial.

Background: The inappropriate management of pain after thoracotomy results in serious complications. Several adjuvants have been added to the thoracic paravertebral block (TPVB) to enhance its effects. This work aimed to evaluate the effect of adding ketamine to TPVB on thoracotomy-related acute and chronic pain. Methods: This randomized controlled double-blinded trial included 60 patients scheduled for open thoracotomy. Patients were equally randomized into 2 groups: group K: received TPVB + 1 mL ketamine (50 mg). Group C (n = 30): received TPVB (19 mL of 0.5% levobupivacaine + 1 mL normal saline) as a control arm. Results: Group K exhibited a significant delay in requesting analgesia, required less morphine in the first 24 and 48 hours, and reported lower numerical rating scale at rest and at deep breathing at various time points compared with the control group. However, both groups were comparable in post-thoracotomy pain syndrome and the incidence of complications at 2 months and 3 months. Conclusions: Adding ketamine to TPVB resulted in better analgesia as demonstrated by significantly delayed time to first rescue analgesia, lower total amount of consumed opioid, and pain score without considerable effect on chronic pain and complications in patients undergoing thoracotomy.