Comparative study between intravenous and local dexamethasone as adjuvant to bupivacaine in perianal block

Background and objectivesEarly ambulation after hemorrhoidectomy as an outpatient procedure can be provided by perianal block with local anesthesia. The objective of this study was to compare the analgesic effects of dexamethasone locally and intravenously when combined with bupivacaine and to compare it with bupivacaine as a sole local anesthetic in the perianal block technique for ano-rectal surgeries.Patients and methods60 ASA I, 20–40 years of age male patients, undergoing ano-rectal surgeries under perianal block local anesthesia were randomly allocated to one of three groups: Bupivacaine group, Local dexamethasone (LD) group and Intravenous dexamethsone (IVD) group. Measurements included the onset of sensory and motor blockade, duration of analgesia, VAS at 6 h following rescue analgesic, and postoperative nausea and vomiting.ResultsThe onset of sensory and motor blockade was significantly shorter in the LD and IVD groups than in the bupivacaine group (3.8 ± 0.7, 4 ± 0.7 vs. 3.8 ± 0.9, 4 ± 1 vs. 5.5 ± 1.2, 6.5 ± 1.1, respectively, P < 0.01). The duration of analgesia was significantly prolonged in the LD and IVD groups compared to the bupivacaine group (287.7 ± 21 vs. 286.2 ± 16.9 vs. 162.3 ± 16.9, respectively, P < 0.01). Postoperative VAS was significantly lower in the LD and IVD groups compared to the bupivacaine group (1.8 ± 0.8 vs. 1.8 ± 0.8 vs. 4.7 ± 0.4, respectively, P < 0.01). The incidence of nausea and vomiting were significantly lower in the dexamethasone groups.ConclusionDexamethasone when used as an adjuvant to bupivacaine in the perianal block for ano-rectal surgeries can accelerate the onset of blockade and prolong the postoperative analgesia.