Spinal anesthesia is the most common approach used for lower abdominal surgeries. Levobupivacaine 0.5% and racemic bupivacaine 0.5% are equally effective in spinal anesthesia. Dexmedetomidine (a highly selective alpha-2 adrenergic agonist) and fentanyl (short-acting synthetic opioid) are effective intrathecal adjuvants. The aim of our study was to evaluate onset and duration of sensory and motor block, duration of postoperative analgesia, and side effects on addition of dexmedetomidine and fentanyl as adjuvants to hyperbaric 0.5% levobupivacaine along with the control group.

Ninety patients of American Society of Anesthesiologists (ASA) grade I/II undergoing infraumbilical surgery were studied in a prospective, double blind, controlled study. Levobupivacaine was made hyperbaric by adding 1 mL of 25% dextrose to 12.5 mg levobupivacaine. Patients were randomly allocated to receive either 12.5 mg hyperbaric levobupivacaine + normal saline (group A, n = 30) or 12.5 mg hyperbaric levobupivacaine + 25 μg fentanyl (group B, n = 30) or 12.5 mg hyperbaric levobupivacaine + 5 μg dexmedetomidine (group C, n = 30) intrathecally.

Patients in the dexmedetomidine group had significantly longer sensory and motor block time than patients in the fentanyl and control groups. Mean time of sensory regression to S1 was 161.2 ± 14.6, 180.3 ± 6.2, and 472.5 ± 8.7 minutes in groups A to C respectively (p < 0.0001). Duration of analgesia was prolonged to 259.4 ± 12.8 minutes in group C as compared with 114.0 ± 14.3 and 161.8 ± 8.5 minutes in the control and fentanyl group respectively (p < 0.0001).

Intrathecal 5 μg dexmedetomidine seems to be an attractive alternative to 25 μg fentanyl as adjuvant to 0.5% hyperbaric levobupivacaine in spinal anesthesia. It is associated with prolonged motor and sensory block and provides good quality of intraoperative analgesia and extended duration of postoperative analgesia as compared with fentanyl.

Jain S, Sharma G, Bafna U, Jain D, Meena S, Jetley P. A Comparative Study of Intrathecal Fentanyl and Dexmedetomidine as Adjuvants to Hyperbaric Levobupivacaine 0.5% and Hyperbaric Levobupivacaine 0.5% Alone in Infraumbilical Surgeries. J Recent Adv Pain 2016;2(2):44-48.