Intrathecal fentanyl and dexmedetomidine with hyperbaric bupivacaine for prolongation of analgesia in elderly patients undergoing lower abdominal and lower limb surgeries- a prospective randomized study

Background: Subarachnoid block is still the most commonly used anesthetic technique for lower abdominal and lower limb surgeries, however local anesthetics alone are associated with relatively short duration of action. Intrathecal adjuvants have been reported to improve the quality of anesthesia along with prolongation of postoperative analgesia and are gaining popularity nowadays. The aim of our study was to compare dexmedetomidine and fentanyl as intrathecal adjuvants to 0.5% hyberbaric bupivacaine with respect to onset and duration of sensory and motor block, duration of analgesia, hemodynamic variations and incidence of side effects.
Method: Fifty two patients of either sex aged 65 to 85 yrs belonging to ASA grade I and II posted for lower limb and lower abdominal surgeries were randomly divided into two groups. Group D was administered hyperbaric bupivacaine 15 mg + dexmedetomidine 5 μg in 0.5 ml normal saline, group F was administered hyperbaric bupivacaine 15 mg + fentanyl 25 μg (0.5 ml)
Result: There was no statistically significant difference between the two groups with respect to onset of sensory and motor block (p > 0.05). The mean time for two segment sensory regression was significantly lower in group D as compared to group F (p < 0.05).Patients in group D had significantly prolonged duration of sensory and motor block as compared to group F (p < 0.05). The duration of analgesia was significantly prolonged in group D (p < 0.05), along with reduced requirement of rescue analgesia. The patients in the two groups did not show any significant difference with respect to hemodynamic changes and incidence of side effects (p > 0.05).
Conclusion: Dexmedetomidine as intrathecal adjuvant in elderly patients was found to prolong sensory and motor block, provided good quality of intraoperative analgesia, prolonged postoperative analgesia with reduced demand for rescue analgesia as compared to fentanyl along with stable hemodynamics and minimal side effects.