Comparing the effect of adding dexmedetomidine versus dexamethasone on prolonging the duration of intrathecal bupivacaine in lower abdominal operations

Objective The aim of this study was to evaluate the efficacy of adding dexmedetomidine compared with dexamethasone to bupivacaine to prolong the duration of spinal anesthesia and analgesia in lower abdominal operations. Patients and methods This randomized double-blind study included 60 ASA I or II patients, aged between 25 and 55 years old, scheduled for lower abdominal operations. They were administered 0.5% intrathecal bupivacaine injection and randomly divided into one of three groups: control group (GC), in which patients were administered additional 1 ml of saline; GDX group, in which patients were administered 4 mg dexamethasone; and GDM group, in which patients were administered 10 μg dexmedetomidine. The patients were monitored for heart rate, mean arterial pressure, oxygen saturation, onset and duration of sensory and motor block, intraoperative and postoperative sedation and pain, and adverse events. Results Compared with GC, GDM had significantly faster onset of sensory block (P = 0.006), longer duration of sensory block (P 0.001), longer duration of motor block (P = 0.013), longer duration of postoperative analgesia (P 0.001), and significantly higher sedation score (P 0.001). Compared with GDX, GDM had significantly longer duration of sensory block (P = 0.025) and longer duration of postoperative analgesia (P 0.001). Compared with GC, GDX had significantly longer duration of sensory block (P 0.001) and longer duration of postoperative analgesia (P 0.001). The three groups were comparable in terms of the onset of motor block (P = 0.637) and frequency of adverse events. Conclusion Intrathecal dexmedetomidine and dexamethasone are safe and effective adjuncts to intrathecal bupivacaine anesthesia in lower abdominal surgery. Dexmedetomidine showed to provide more rapid onset and longer duration of sensory block, longer duration of motor block, and longer postoperative analgesia.