Comparison of dexmedetomidine and fentanyl as intrathecal adjuvants to 0.5% hyperbaric bupivacaine for total abdominal hysterectomy under subarachnoid block: A prospective randomized double blind study

Abstract

Background: Subarachnoid block is still the most commonly used anesthetic technique for lower abdominal surgeries, however local anesthetics alone are associated with relatively short duration of action. The intrathecal adjuvants has been reported to improve the quality of anesthesia along with prolongation of postoperative analgesia and has gained popularity nowadays. So the aim of our study was to compare the dexmedetomidine and fentanyl as intrathecal adjuvant 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.

Methodology: Sixty four female patients, aged 30-60 years, belonging to American Society of Anesthesiologists (ASA) physical status І or ІІ, scheduled for elective total abdominal hysterectomy with or without bilateral salpingo-oophorectomy were randomly allocated into two groups, Group BD received 2.5 ml of 0.5% hyperbaric bupivacaine and 5 μg dexmedetomidine diluted in 0.5 ml preservative free normal saline while Group BF received 2.5 ml of 0.5% hyperbaric bupivacaine and 25 μg (0.5 ml) fentanyl.

Results: There was no statistically significant difference between two groups with respect to onset of sensory and motor block (p > 0.05). The mean time for two segment sensory regression was significantly slower in Group BD as compared to Group BF (p < 0.05). Patients in Group BD had significantly prolonged duration of sensory and motor block as compared to Group BF (p < 0.05). Similarly the duration of analgesia was significantly prolonged in Group BD (p < 0.05), along with reduced requirement of rescue analgesics. The patients in both 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 was found to have prolonged sensory and motor block, provide good quality of intraoperative analgesia, stable hemodynamics, minimal side effects and prolonged postoperative analgesia along with reduced demand for rescue analgesics as compared to fentanyl.