Effectiveness of perineural administration of dexamethasone with lidocaine on onset time of sensory block and early postoperative analgesia in axillary brachial plexus block: a prospective cohort study, Ethiopia

Abstract

Introduction: The axillary brachial plexus block is a popular nerve block for forearm, wrist, and hand surgery. The aim of this study was to assess the effectiveness of perineural administration of dexamethasone as an adjunct to lidocaine with adrenaline on the onset of sensory block and early postoperative analgesia in trans-arterial axillary brachial plexus block.

Methodology: This single-centered prospective cohort study recruited 68 adult patients, 34 in each groups. The frequently used 8 mg dexamethasone combined with 1% lidocaine and adrenaline was investigated. The normality of the data was checked using the Shapiro-Wilk test. An independent t-test was used to compare the mean values of symmetric numeric data. Categorical variables between the two groups were analyzed using χ². The Mann-Whitney U test and Kaplan-Meier method using the log-rank test were used to compare asymmetric numeric data, and a P-value of <0.05 was considered as significant.

Results: The median onset time of sensory block was comparable between the nonexposed (24(6) min) and exposed group (24(6) min) (P=0.068). However, the duration of sensory block was significantly longer in the exposed group (235.5±37.51 min) than the nonexposed group (172.76±28.19 min) (P<0.001). The time to the first analgesic request was significantly longer in the exposed than the nonexposed group (P<0.01). Postoperative pain scores were significantly lower at 4 and 8 h in the exposed group (P<0.05).

Conclusion and recommendations: The addition of 8 mg dexamethasone to 1% lidocaine with adrenaline solution in trans-arterial axillary brachial plexus block for ambulatory elective hand, wrist, and forearm surgeries prolonged the duration of sensory blockade and the first analgesic request time but did not reduce the onset time of sensory block. The authors recommend the addition of 8 mg dexamethasone to 1% lidocaine with adrenaline solution to prolong the duration of sensory block and the first analgesic request time.

Keywords: Brachial plexus block; adrenaline; lidocaine; perineural dexamethasone; postoperative analgesia.

Figure 1

Comparison of median onset time of analgesia (in minutes) for all nerves of axillary block Mann–Whitney U test was used for analysis. MN, median nerve; MCN, musculo cutaneous nerve; RN, radial nerve; UN, ulnar nerve.

Figure 2

Comparison of cumulative frequency of patients recovered from analgesia at a given time between the groups, analyzed using the Fisher exact test at 130 min and the χ² test at 172, 214, 256, and 298 min. * indicate P<0.05.

Figure 3

Kaplan–Meier curves (log-rank test) for the first analgesic request (P<0.001).

Figure 4

Comparison of incidence of nausea and vomiting between the two groups.