Randomized Controlled Study Using Ropivacaine with Intravenous Adjuvants in Spinal Anaesthesia In Lower Limb...

In recent years, several adjuvants have been used to prolong the duration of the subarachnoid block. These adjuvants have either been used via intrathecal route or intravenous (i.v.) route. Dexmedetomidine and clonidine have been used as adjuvants to local anesthetic drugs by intrathecal, epidural, caudal, and i.v. routes and for peripheral nerve blocks. In this study, we endeavored at finding the efficacy of dexmedetomidine and clonidine in improving the analgesia quality and duration of the subarachnoid block.

A prospective, double-blind, randomized control trial comprising 70 subjects posted for elective lower limb surgeries.

Seventy patients were selected at random and were allocated to two groups (Group C and Group D) of 35 each. In Group C, the patients received isobaric ropivacaine with clonidine 1.0 μg.kg^-1 intravenously. In Group D, the patients received isobaric ropivacaine with dexmedetomidine 0.5 μg.kg^-1 intravenously. Perioperatively, heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure, and oxygen saturation were recorded and documented every 5 min till the end of surgery. Time of onset, level of sensory blockade, and duration of sensory blockade were recorded. Motor block was assessed using modified Bromage scale. Data validation and analysis were carried out by SPSS version 16. A P < 0.05 was considered statistically significant.

Time of onset of sensory block in Dexmedetomidine group and Clonidine group was 2.70 ± 1.25 minutes and 3.50 ± 1.23 minutes respectively (P = 0.021). Time of onset of motor block in Dexmedetomidine group and Clonidine group was 3.55 ± 1.60 minutes and 4.30 ± 1.45 minutes respectively (P = 0.034). Time for 2 segment regressions of sensory block in Dexmedetomidine group and Clonidine group was 140.30 ± 12.32 minutes and 125.65±14.33minutes respectively (P = 0.047). Time of regressions of motor blockade to Bromage Scale 1 in Dexmedetomidine group and Clonidine group was 148.65 ± 15.23 minutes and 129.70 ± 19.35 minutes respectively (P = 0.032).

The use of i.v. dexmedetomidine perioperatively prolongs the duration of sensory and motor block significantly when compared to i.v. clonidine.