Comparison of perineural dexamethasone and dexmedetomidine as adjuvants in reducing rebound pain in patients undergoing peripheral nerve block: A double blind randomized controlled study.

Background and Aims: Rebound pain (RP) is a distressing, yet not much explored, entity. This study aimed to evaluate and compare how adjuvants like dexamethasone and dexmedetomidine added to 0.5% ropivacaine for peripheral nerve block (PNB) can impact RP. Material and Methods: In this randomized, double-blinded study, 72 patients posted for elective upper limb surgeries under brachial plexus block were randomly divided into three groups of 24 each. Group A received 28 ml 0.5% ropivacaine +2 ml normal saline, Group B received 28 ml 0.5% ropivacaine + 8 mg dexamethasone (2 ml), and Group C received 28 ml 0.5% ropivacaine +50 µg dexmedetomidine (2 ml). The incidence and onset of RP, as well as the duration of sensory and motor block, were compared between the groups. The distribution of variables was compared using appropriate statistical tests. Results: On postoperative days 1 and 2, the RP incidence was significantly lower in the dexmedetomidine group (12.5%, 16.67%) and dexamethasone group (25%, 20.83%), compared to the control group (54.17%, 58.33%) ( Conclusions: The incidence of RP is significantly reduced when dexmedetomidine and dexamethasone are added as adjuvants to 0.5% ropivacaine in upper limb PNBs, with dexmedetomidine being superior in this regard.