Background: Spinal anesthesia is used commonly intraoperatively. However, local anesthetics are associated with relatively short duration of action. A number of adjuvants have been used to prolong the postoperative analgesia.
Objectives: To compare efficacy of dexmedetomidine and fentanyl when given intrathecally as an adjuvant to 2.5 ml of 0.75% isobaric ropivacaine.
Materials and methods: Sixty selected patients were randomized to receive 2.5 ml of 0.75% isobaric ropivacaine with dexmedetomidine 5 mcg (Group RD) or 20 mcg of fentanyl (Group RF) intrathecally for lower limb surgeries, block characteristics, hemodynamic changes, and adverse effects were compared.
Results: Efficacy of both the drugs when given intrathecally was studied. Mean time needed for sensory blockade at T10 was 156.4667 ± 33.78 s in Group RD and 185.2000 ± 35.17 s in Group RF. The results are clinically and statistically significant (P - 0.002). The mean of total duration of sensory block in Group RD was 194.400 min while it was 139.9000 min in Group RF which was clinically and statistically significant (P - 0.0001). Time taken for onset of motor block was almost same in both groups. The mean of total duration of motor block in Group RD was 136.7333 min while it was 94.8667 min in Group RF which was clinically and statistically significant (P - 0.000).
Conclusion: Dexmedetomidine at a dose of 5 μg added to 2.5 ml of ropivacaine provided earlier sensory blockade, prolonged duration of sensory and motor blockade for patients under intrathecal anesthesia for lower limb surgeries with no sedation.
Keywords: Dexmedetomidine; duration of block; fentanyl; isobaric ropivacaine; spinal anesthesi.