Effect of Dexamethasone as an Adjuvant to Bupivacaine for Ultrasound-guided Axillary Plexus Block: A Randomized, Double-blinded Prospective Study.

Abstract

Objectives: The study evaluated sensory and motor block onset time, duration, and intensity, as well as pain intensity, sedation levels, and vital signs, showing that adding dexamethasone to bupivacaine improved sensory and motor block onset time, duration, and intensity, enhanced sedation effects. Axillary plexus block is a common type of anesthesia for surgical management of upper extremity injuries.

Methods: This prospective clinical trial included 72 patients over 18 years of age who were candidates for surgical management of upper extremity injuries with the axillary plexus block approach. The patients were randomly divided into two groups: group BD [30 ml bupivacaine 0.25% with 2ml dexamethasone (n=36)] and group B [30 ml bupivacaine 0.25% with 2ml distilled water (n=36)]. The Pinprick test and Modified Bromage Scale (MBS) were used to evaluate the sensory and motor block levels. Additionally, the Visual Analogue Scale (VAS) and Ramsay Sedation Scale (RSS) were used to assess pain intensity and degree of sedation. All collected data were analyzed using IBM SPSS Statistics version 20 software.

Results: The mean age of patients in the B and BD groups was 34.41±11.11 and 36.8±13.3, respectively. According to the results, there was a significant difference in the average time of sensory and motor block onset between two groups, with group BD showing shorter onset time compared to group B (P<0.001). Moreover, the mean duration and intensity of the sensory and motor block were significantly higher in group BD (P<0.05). Additionally, the degree of sedation changes after the block started were more pronounced in group BD. There was no statistically significant difference between the two groups regarding changes in pain intensity, heart rates (HR), mean arterial blood pressure (MABP), and complications (P>0.05).

Conclusion: Adding dexamethasone to bupivacaine as a safe adjuvant drug effectively prolongs the axillary plexus block time duration and reduces post-surgery pain. Furthermore, it accelerates the onset time of sensory and motor block.