Comparison the Effect of Intermittent Low Dose Ketamine and Marcaine Infusion through the Sub-pleural Catheter in the Post-Thoracotomy Pain

Lack of adequate relief of pain after thoracotomy can cause many complications. In this study the effect of using low dose ketamine through sub pleural catheter for pain relief after thoracotomy were compared with marcaine. In this prospective clinical trial study, patients undergoing elective thoracotomy were included. After thoracotomy, for pain relief the patients in case and control groups received 0.5 mg/kg/hr ketamine and 5 cc marcaine 0.5% through sub pleural catheter, respectively. Vital signs, arterial oxygen saturation, and pain level of patients in both groups were recorded and compared at 1 hour after the surgery in recovery and at 8, 16, and 24 hours after surgery In ketamine and marcaine groups, 41 and 51 patients were studied, respectively. Mean pain level before intervention and 8, 16, and 24 hours after it was higher in ketamine group (P < 0.05). One hour after local injection of local anesthetic drugs, the level of pain relief was similar in two studied groups (P > 0.05). Systemic analgesic dose used after thoracotomy was significantly lower in marcaine group than ketamine group (P < 0.05). Mean difference of pain before and after injection of local anesthetic drugs in the two groups did not different significantly (P > 0.05). Low-dose ketamine likewise marcaine could be used as a known local anesthetic for post-operative pain relief but this pain reduction is less due to the short half-life of ketamine.