Comparison of Analgesic Efficacy of Dexmedetomidine and Midazolam as Adjuncts to Lignocaine for Intravenous Regional Anesthesia

Abstract

Background: Intravenous regional anesthesia (IVRA) is safe, technically simple, and cost-effective technique compared to general anesthesia with success rates of 94-98% for upper and lower limb surgeries. The main disadvantage of this procedure is its limited duration for surgery, lack of postoperative analgesia, and tourniquet pain. To overcome this disadvantage, various adjuvants to lignocaine have been studied from time to time.

Aim: To compare the analgesic efficacy of dexmedetomidine and midazolam as adjuncts to lignocaine for IVRA for forearm and hand surgeries.

Setting and design: The study was conducted by the Department of Anaesthesia of Medical College and patients posted for elective as well as the emergency forearm and hand surgeries were included in the study. It was a prospective comparative study.

Materials and methods: Sixty patients of either sex belonging to the American Society of Anesthesiologists Class I and II, in the age range of 18-65 years, scheduled for upper limb orthopedic surgery, either elective or emergency, were included in the study. All patients were administered IVRA in this prospective, double-blind, randomized study. Patients enrolled in the study were randomly divided into two groups of thirty each. Group M-received 40 ml of 0.5% lignocaine with midazolam 50 μg/kg and Group D-received 40 ml of 0.5% lignocaine with dexmedetomidine 1 μg/kg. Time of onset of sensory block, duration of analgesia, total dose of fentanyl given, intraoperative blood pressure, oxygen saturation, heart rate, postoperative analgesia, and adverse effects were recorded and compared between the groups.

Statistical analysis used: The statistical evaluation was performed using SPSS version 17.0 software. All values were calculated with a 95% confidence interval. The parameters were expressed as mean ± standard deviation and t-test was used for comparing demographic and clinical data. For comparisons, P < 0.05 was considered statistically significant.

Results: Mean duration of analgesia was 93 ± 28 min in dexmedetomidine group and 84 ± 28 min in midazolam group, and onset of sensory block was comparable in both groups.

Conclusion: Dexmedetomidine and midazolam, when used as adjuvants to lignocaine for IVRA, significantly improve the intraoperative conditions by providing superior quality of block. The superiority of one over the other could not be established as midazolam produced the early onset of block and less requirement of fentanyl, whereas dexmedetomidine when added to IVRA provided longer duration of analgesia (93 ± 28 min) in comparison to midazolam (84 ± 28 min).

Keywords: Adjuvants; dexmedetomidine; intravenous regional anesthesia; lignocaine; midazolam.

Figure 1

Onset of sensory block (mean ± standard deviation).

Figure 2

Mean dose of fentanyl required.