A Comparison of Intrathecal Dexmedetomidine and Fentanyl as Adjuvants to 0.5% Hyperbaric Levobupivacaine for Lower Abdominal Surgeries: A Prospective, Double-Blinded, Randomized Controlled Trial.

Background Due to its affordability and ease of application, the subarachnoid block is the most frequently used method for lower abdominal procedures. Levobupivacaine has an onset of sensory and motor blockade comparable to that of bupivacaine and prolongs the duration of analgesia while facilitating quick recovery from motor block. Fentanyl and dexmedetomidine, when used as additives to intrathecal local anesthetic, can extend the duration of sensory and motor blockade and enhance postoperative analgesia. Aims and objectives The purpose of this study is to examine and compare the effectiveness of fentanyl and dexmedetomidine administered as adjuvants to 0.5% hyperbaric levobupivacaine intrathecally in lower abdominal operations with respect to block characteristics, postoperative analgesia as measured by visual analog scale (VAS) scores, hemodynamic changes, and adverse effects. Materials and methods Seventy patients were randomized into two groups of 36 each. Group LF received 15mg of 0.5% hyperbaric levobupivacaine with 25mcg of fentanyl, and Group LD received 15mg of 0.5% hyperbaric levobupivacaine with 10mcg of dexmedetomidine intrathecally. Results Patients in Group LD had a significantly longer duration of sensory and motor block than those in Group LF. In Group LF, the onset of sensory and motor blockade was faster (6.25 ± 1.89 minutes and 9.00 ± 3.24 minutes) compared to Group LD (8.70 ± 1.93 minutes and 10.95 ± 4.03 minutes). The length of sensory and motor blockade in Group LD was longer than in Group LF (308.28 ± 6.36 minutes vs. 232.28 ± 7.01 minutes and 198.20 ± 6.52 minutes vs. 157.45 ± 6.30 minutes, respectively). The total postoperative requirement for analgesics in the initial 24 hours, and the mean VAS scores were lower in Group LD. Conclusion Patients in Group LD experienced a significantly longer duration of sensory and motor block than those in Group LF. The onset of sensory and motor blockade was significantly faster in Group LF than in Group LD. The total postoperative requirement for analgesics in the initial 24 hours and the mean VAS scores were lower in Group LD. This concludes that the use of dexmedetomidine as an adjuvant to 0.5% hyperbaric levobupivacaine during the subarachnoid block provides prolonged postoperative analgesia, reduces total analgesic requirements, and maintains stable hemodynamics, while the use of fentanyl as an adjuvant to hyperbaric levobupivacaine enhances the onset of both sensory and motor blockade.