Effect of Dexamethasone as an Adjuvant to Bupivacaine in Supraclavicular Brachial Plexus Block for Prolongation of Analgesia - A Comparative Study

Background: The supraclavicular brachial plexus block is a widely employed regional anesthetic technique for upper limb surgeries, offering effective intraoperative anesthesia and postoperative pain relief. Bupivacaine, a commonly used local anesthetic, provides excellent nerve blockade but its effects are limited to a few hours. To enhance the efficacy and prolong the duration of analgesia, various adjuvants have been studied. Among these, dexamethasone has shown promising results in extending analgesic effects. This study investigates the impact of adding dexamethasone to bupivacaine on the onset and duration of sensory and motor blocks, duration of analgesia, and potential adverse effects. Materials and Methods: This prospective, double-blind, randomized controlled trial was conducted in a period of February 2024 to November 2024 at DKS Post Graduate lnstitute and Research Centre, Raipur, Chhattisgarh, India, included 80 patients aged 18–60 years, classified as ASA grades I–II, undergoing upper limb surgeries under supraclavicular brachial plexus block. The patients were randomly divided into two groups. Group BD received 28 mL of 0.5% bupivacaine combined with 2 mL dexamethasone (8 mg), while Group BN received 28 mL of 0.5% bupivacaine with 2 mL normal saline. The onset and duration of sensory and motor blocks were assessed using a pinprick test and the Bromage scale, respectively. The duration of analgesia was defined as the time from the onset of the sensory block to the first request for rescue analgesia. Hemodynamic parameters, including heart rate, blood pressure, respiratory rate, and oxygen saturation (SpO2), were recorded. Adverse effects were monitored for 24 hours postoperatively. Data analysis was conducted using SPSS v17.0, with a significance threshold of p<0.05. Results: The demographic characteristics of the two groups were comparable. The study revealed significant differences in the onset and duration of sensory and motor blocks between the groups. The mean onset time for the sensory block was slightly prolonged in Group BD (13.18 ± 1.65 min) compared to Group BN (12.53 ± 1.13 min), with a p-value of 0.04. Similarly, the onset of the motor block was significantly longer in Group BD (18.48 ± 2.2 min) than in Group BN (14.75 ± 1.28 min), with a p-value of <0.001. The duration of the sensory block was markedly extended in Group BD (667 ± 31.31 min) compared to Group BN (376.75 ± 13.33 min, p<0.001). The motor block duration also showed a significant increase in Group BD (587.13 ± 29.04 min) compared to Group BN (338.5 ± 9.62 min, p<0.001). Furthermore, the duration of analgesia was significantly longer in Group BD (720.5 ± 11.86 min) compared to Group BN (430.13 ± 15.55 min, p<0.001). Hemodynamic parameters, including heart rate, systolic and diastolic blood pressure, respiratory rate, and oxygen saturation, remained stable in both groups (p>0.05). Notably, no adverse effects were observed in either group throughout the monitoring period. Conclusion: The study demonstrates that the addition of dexamethasone to bupivacaine in supraclavicular brachial plexus blocks significantly enhances the duration of sensory and motor blocks as well as postoperative analgesia without associated adverse effects. This finding supports the use of dexamethasone as an effective adjuvant in regional anesthesia for upper limb surgeries. Its incorporation into clinical practice could provide improved pain management and patient satisfaction.