Comparing fentanyl and dexmedetomidine as adjuvants to bupivacaine for spinal anesthesia in appendectomy: effects on peritoneal symptoms – a randomized clinical trial

BACKGROUND: Peritoneal symptoms, including visceral pain, abdominal discomfort, and vagal responses (e.g., nausea, bradycardia), are common during abdominal surgeries under spinal anesthesia. This study compared intrathecal dexmedetomidine and fentanyl for their effectiveness in controlling these symptoms during appendectomy. METHODS: This randomized, double-blinded clinical trial included 150 patients of the American Society of Anesthesiologists I, II physical status scheduled for emergency open appendectomy. Participants were randomly assigned to receive either intrathecal dexmedetomidine (5 μg, Group D) or fentanyl (25 μg, Group F), both combined with 0.5% hyperbaric bupivacaine. RESULTS: Dexmedetomidine significantly reduced the incidence of peritoneal symptoms compared to fentanyl: abdominal discomfort (9.5% vs. 33.3%), visceral pain (10.8% vs. 53.3%), nausea (9.5% vs. 34.7%), and vomiting (6.8% vs.34.7%) (P < 0.001). The time to first rescue analgesia was significantly longer in the dexmedetomidine group (396 vs. 243 min; P < 0.001). Bradycardia was more frequent in group D (25.7% vs. 1.3%, P < .001); no cases of respiratory depression were observed. Hypotension occurred slightly more frequently in group D, whereas shivering was more prevalent in group F; however, neither difference reached statistical significance. The VAS was significantly higher in group F than in group D at four and six hours postoperatively (P < 0.001). CONCLUSIONS: Dexmedetomidine provides superior peritoneal symptom control and prolonged analgesia compared to fentanyl as an intrathecal adjuvant in spinal anesthesia for appendectomy. Despite a higher incidence of bradycardia, its opioid-sparing benefits and overall safety make it a valuable alternative, particularly for procedures involving significant visceral manipulation.