Comparison of Dexmedetomidine and Ketamine in Serratus Anterior Plane Block for Postoperative Pain Control in Thoracotomy Patients: A Randomized Clinical Trial.

Background: Postoperative pain control after thoracotomy is very important, and if not controlled, it can cause severe complications. Objectives: This study aimed to compare dexmedetomidine and ketamine in serratus anterior plane block (SAPB) in pain control after thoracotomy. Methods: This randomized clinical trial was conducted on 74 patients aged 18 to 60 years old with American Society of Anesthesiologists (ASA) class I or II who were referred to Imam Khomeini hospital in Ahvaz, Iran, for thoracotomy and randomly divided into two groups. After surgery, the SAPB with ultrasound-guided was performed. In the ropivacaine-ketamine (RK) group, ketamine 0.5 mg/kg and 0.4 cc/kg ropivacaine solution 0.25% and in the ropivacaine-dexmedetomidine (RD) group, in addition to 0.4 cc/kg ropivacaine 0.25%, dexmedetomidine 0.5 µg/kg was added. Verbal Numeric Scale (VNS), systolic blood pressure (SBP), diastolic blood pressure (DBP), respiratory rate (RR), heart rate (HR), and mean arterial blood pressure (MAP) were recorded. Results: There was no significant difference in both groups in terms of demographic information (P < 0.05). The average VNS was lower in the ketamine group than in the dexmedetomidine group; however, there was a significant difference only at 1, 12, and 24 hours after surgery (P < 0.05). There was no statistically significant difference between the two groups in terms of SBP and DBP, HR, and MAP. There was a significant difference in the RR in the two groups at 12 and 24 hours after the operation (P < 0.05). Conclusions: Dexmedetomidine and ketamine, which were used as supplements to ropivacaine for SAPB in patients undergoing elective thoracotomy, reduced the pain intensity after thoracotomy; nevertheless, the intensity of pain reduction was more and more effective in the group receiving ketamine.