Context: Bupivacaine is the most common local anesthetic agent used for brachial plexus blocks (BB). Due to the adverse effects noted with bupivacaine, safer alternative agents such as levobupivacaine and ropivacaine are being used now. Aims: Although several studies exist comparing pairs of anesthetic agents, few studies have compared all three agents using dexmedetomidine (DMT) as an adjuvant. To bridge this knowledge gap, we undertook the present study. Settings and Design: This was a prospective, randomized, placebo-controlled, triple-blind comparative study. Materials and Methods: Eighty patients were randomly allocated to four study groups: group B, given bupivacaine alone, and groups BD, LD, and RD, given twenty-five ml of 0.5% bupivacaine, 0.5% levobupivacaine, and 0.75% ropivacaine, respectively, along with DMT 0.5 μg/kg body weight. Onset of the sensory and motor blocks; duration of the sensory block, motor block and analgesia of the block were compared between the groups. Statistical Analysis Used: Differences between the groups were analyzed using one-way analysis of variance and Tukey's honestly significant difference -β post hoc test for parametric data, and for nonparametric data, Chi-square test and Fisher's exact test were used. Results: The durations of analgesia observed were 7 ± 0.7, 13.4 ± 0.6, 12.7 ± 1.0, and 12.5 ± 0.6 h in groups B, BD, LD, and RD, respectively; these differences were statistically significant (F = 294.825, P < 0.001). Post hoc tests revealed a statistically significant difference between Group B and all the other groups, between the BD and LD groups, and between BD and RD groups. The times to onset of sensory blocks observed were 11.3 ± 11.3, 7.6 ± 0.8, 8.1 ± 0.8, and 8.4 ± 0.8 min in groups B, BD, LD, and RD, respectively, while the times to onset of motor blocks observed were 17.1 ± 1.5, 11.0 ± 0.9, 10.3 ± 1.0, and 10.2 ± 0.7 min in groups B, BD, LD, and RD, respectively. Conclusions: DMT added as an adjuvant to bupivacaine, levobupivacaine, and ropivacaine resulted in a statistically significant enhancement of the duration of analgesia.

Background and Aims: Bupivacaine and lidocaine mixtures are the commonly used local anesthetic drugs for the peribulbar blocks. Because of its safe anesthetic profile, ropivacaine is being investigated as an alternative agent. Several centers have evaluated the effect of the addition of an adjuvant like dexmedetomidine (DMT) to ropivacaine in enhancing the block characteristics. We proposed to evaluate the effect of the addition of DMT to ropivacaine versus a control group not having DMT as adjuvant. Material and Methods: A prospective, randomized comparative study was conducted on a total of 80 patients attending our hospital for cataract surgeries. Patients were allocated into four groups of 20 each ( n = 20) and peribulbar blocks were given 6 mL of 0.75% ropivacaine in group R and 6 mL of 0.75% ropivacaine plus 10 μg, 15 μg, and 20 μg DMT, respectively, in groups RD1, RD2, and RD3. Results: When DMT was used as an adjunct to ropivacaine, there was a prolongation of the duration of the sensory block. Conclusion: In peribulbar blocks, 6 mL of ropivacaine 0.75% produces satisfactory block characteristics, and the addition of 10 μg, 15 μg, or 20 μg of DMT as an adjuvant to ropivacaine 0.75% had the effect of significantly prolonging the duration of the sensory block, which is directly proportional to the dose of DMT employed. However, 20 μg of DMT added as an adjuvant to ropivacaine 0.75% appears to be the optimal dose, as this anesthetic drug mixture provides maximum prolongation of the sensory block besides providing satisfactory operating conditions, acceptable sedation levels, and stable hemodynamic parameters.