Comparative evaluation of ropivacaine versus dexmedetomidine and ropivacaine in epidural anesthesia in lower limb orthopedic surgeries.

BACKGROUND: Various adjuvant are being used with local anesthetics for prolongation of intra operative and postoperative analgesia in epidural block for lower limb surgeries. Dexmedetomidine, the highly selective α2 adrenergic agonist is a new neuroaxial adjuvant gaining popularity. The aim of the present study was to compare the hemodynamic, sedative and analgesia potentiating effects of epidurally administered dexmedetomidine when combined with ropivacaine.

MATERIALS AND METHODS: The study was conducted in prospective, randomized double-blind manner in which 100 patients of American Society of Anesthesiologist Grade I and II in the age group of 20-65 years of either sex under going lower limb surgeries were included after taking informed consent. The patients were randomly allocated into two groups of 50 each. Epidural anesthesia was given with 150 mg of 0.75% ropivacaine in Group A (n = 50) and 150 mg of 0.75% ropivacaine with dexmedetomidine (1 μg/kg) in Group B (n = 50). Two groups were compared with respect to hemodynamic changes, block characteristics which included time to onset of analgesia at T10, maximum sensory analgesic level, time to maximum sensory and motor block, time to regression at S1 dermatome and time to the first dose of rescue analgesia for 24 h. At the end of study, data was compiled and analyzed statistically using Chi-square test, Fisher's exact test and Student t-test. P < 0.05 was considered to be significant and P < 0.001 as highly significant.

RESULTS: Significant difference was observed in relation to the duration of sensory block (375.20 ± 15.97 min in Group A and 535.18 ± 19.85 min in Group B [P - 0.000]), duration of motor block (259.80 ± 15.48 min in Group A and 385.92 ± 17.71 min in Group B [P - 0.000]), duration of post-operative analgesia (312.64 ± 16.21 min in Group A and 496.56 ± 16.08 min in Group B [P < 0.001]) and consequently low doses of rescue analgesia in Group B (1.44 ± 0.501) as compared to Group A (2.56 ± 0.67). Sedation score was significantly more in Group B in the post-operative period.

CONCLUSION: Epidural Dexmedetomidine as an adjuvant to Ropivacaine is associated with prolonged sensory and motor block, hemodynamic stability, prolonged postoperative analgesia and reduced demand for rescue analgesics when compared to plain Ropivacaine.