Effect of intravenous dexamethasone on the duration of hyperbaric bupivacaine spinal anesthesia in lower abdominal surgery, Randomized controlled trial

BACKGROUND: The purpose of this study was to investigate the effect of intravenous (IV) dexamethasone on the duration of hyperbaric bupivacaine spinal anesthesia. METHODS: Two hundred patients between the ages of 18 and 60, of both sexes with ASA I- II classification scheduled for lower abdominal surgery under spinal anesthesia using hyperbaric bupivacaine 0.5% were randomly divided into two groups: the dexamethasone group (Dexa group) and the control group, with 100 patients in each group. Before the administration of spinal anesthesia, the Dexa group received an intravenous infusion of 8 mg dexamethasone in 500 mL normal saline, while the control group received 500 mL normal saline only. The primary outcome of this study was to assess the effect of IV dexamethasone on the regression of hyperbaric bupivacaine spinal anesthesia. Secondary outcome measures included the total duration of sensory and motor blocks, VAS score, time of first analgesic request, total analgesic consumption within the first 24 h, and the occurrence of any side effects. RESULTS: The Dexa group had significantly delayed onset of 2 dermatomes regression (P < 0.001) compared to the control group. Additionally, the Dexa group had significantly longer duration of both sensory block (P = 0.01) and motor block (P < 0.001). The Dexa group had significantly longer duration until the first postoperative analgesic request (P < 0.001) and a lower incidence of side effects compared to the control group. CONCLUSION: Although the intravenous administration of dexamethasone had a limited effect on the duration of hyperbaric bupivacaine spinal anesthesia, it improved postoperative VAS scores compared to the control group and decreased overall postoperative analgesic consumption. Therefore, it can be considered a valuable addition to postoperative multimodal analgesia strategies, aiming to minimize total analgesic consumption. CLINICAL TRIAL REGISTRATION: ID: NCT04778189 (2/3/2021).