A comparative study of the analgesic efficacy of dexamethasone and dexmedetomidine as adjuvants to levobupivacaine for interscalene brachial plexus block in patients undergoing orthopedic shoulder surgeries – a randomized clinical trial

Abstract

BACKGROUND: Shoulder surgery can cause significant postoperative pain. Therefore, control of postoperative pain is important by decreasing the pain to a tolerable level so that patients can return to their day-to-day activities. Regional anesthesia in the form of an interscalene brachial plexus block (ISBPB) is used, either as an adjunct to general anesthesia or as the primary anesthetic to improve analgesia and facilitate early mobilization in patients. Ultrasound-guided ISBPB is a less invasive, easy technique to perform, and has fewer complications than the other procedures. Levobupivacaine, the S-enantiomer of bupivacaine, has cardiotoxicity than bupivacaine. Therefore, it is an ideal neural blocking agent. Dexamethasone is a systemic glucocorticoid with potent anti-inflammatory and analgesic effects. It is routinely used to reduce postoperative nausea, vomiting, and pain. Dexmedetomidine is an alpha 2 adrenoceptor agonist. It is used as an adjuvant to local anesthetics in regional anesthesia. AIMS AND OBJECTIVES: To evaluate the onset time of sensory and motor block, duration of sensory and motor block, time taken for the first rescue analgesia, total dose of rescue analgesia, postoperative visual analogue score (VAS), and additive effects of dexmedetomidine and dexamethasone to levobupivacaine for interscalene brachial plexus block in patients undergoing orthopedic shoulder surgeries. METHODOLOGY:  Written informed consent was obtained. Nil by mouth status was confirmed. IV access was secured using an 18-gauge cannula in patients  Patients underwent pre-anesthetic evaluation with detailed history, airway examination, and systemic examination. The patients have been explained the procedure of block and the visual analogue score. Routine blood investigations were done. 10 Docusign Envelope ID: 2A7A1BA6-51B6-46E2-BBB2-7E81A48E78C2  The block was given with an in-plane technique using a 22 G needle, and Group A received 25 ml 0.5% levobupivacaine with 8 mg dexamethasone as an adjuvant. In contrast, Group B received 25 ml 0.5% levobupivacaine with 50 mcg dexmedetomidine and 1.5 ml sterile water as an adjuvant.  Patients were evaluated for the onset time of sensory and motor block and the duration of sensory and motor block.  Patients were also evaluated for the time taken for the first dose of rescue analgesia and the requirement of the total dose of rescue analgesia  Patients were assessed for postoperative visual analogue scores for both groups at 2, 6, 8, 10, 12, and 24 hours post-surgery. RESULTS:  Age and gender were comparable and statistically insignificant.  The onset time of sensory and motor blockade was significantly faster in Group A than in Group B.  The duration of action was significantly longer in Group B than in Group A.  The time taken for the first rescue analgesic is significantly longer in Group B than in Group A.  The total dose of analgesic given was significantly lower in Group B than in Group A.  VAS scores were significantly better in Group B than in Group A. CONCLUSION: In conclusion, with all the above findings, which are statistically significant, dexmedetomidine has better action as analgesia than dexamethasone when used as an adjuvant to levobupivacaine for ISBPB in patients undergoing shoulder surgeries.