The Effect of Ketamine and Dexamethasone in Combination with Lidocaine on the Onset and Duration of Axillary Block in Hand and Forearm Soft Tissue Surgery

BACKGROUND: Using peripheral nerve block compared to general anesthesia has gained more popularity due to reduced postoperative pain, less need for post-surgery analgesic drugs, reduced incidence of nausea, shortness of PACU time, and increased patient satisfaction. OBJECTIVES: The aim of this study was to compare the effect of ketamine and dexamethasone as additives to lidocaine on duration and onset of axillary block action. METHODS: In this clinical trial, all patients who referred to Hazrat-e-Fatemeh hospital for forearm and hand soft tissue surgery with informed consent were randomly divided into three groups in order to examine the onset and duration of axillary block: lidocaine + ketamine, lidocaine + dexamethasone in axillary block, and lidocaine alone (control). Then, the onset and duration of sensory and motor blocks were measured and recorded every three minutes and after the surgery. Quantitative and qualitative variables were analyzed using ANOVA or Kruskal–Wallis test and Chi-square or Fisher exact test in SPSS v.22. RESULTS: Duration of sensory and motor block axillary was significantly higher in lidocaine + dexamethasone group than in lidocaine + ketamine group (P < 0.05); it was also significantly higher in lidocaine + ketamine group compared to lidocaine group (P < 0.05). However, there was no significant difference in the onset of sensory and motor block axillary between the three groups (P > 0.05). CONCLUSIONS: According to the results of our study, we can conclude that adding dexamethasone or ketamine to lidocaine could improve duration of sensory and motor axillary block in patients undergoing forearm and hand soft tissue surgery. However, dexamethasone had the highest effect on duration of block axillary. We proved that dexamethasone or ketamine added to lidocaine had no effect on the onset of block axillary.