Abstract
PURPOSE: Intrathecal fentanyl improves intraoperative analgesia and reduces hypotension by enhancing subtherapeutic local anesthetic doses during cesarean sections. This study explores whether these advantages are affected by the negative circulatory effects of carbetocin after delivery. PATIENTS AND METHODS: This randomized double-blind, non-inferiority trial was conducted at a tertiary hospital in China. Sixty patients who underwent cesarean section, with singletons, were randomly assigned to receive either spinal anesthetic 15 mg ropivacaine combined with 10 µg fentanyl (Group F) or 16.5 mg ropivacaine (Group R). Slow intravenous carbetocin was routinely administered after delivery. Primary outcomes included hypotension incidence and anesthesia success rate (non-inferiority margin of 0.20). Secondary outcomes included analgesic supplementation time after anesthesia, vasopressor use, neonatal outcomes, patient satisfaction with anesthesia and postoperative analgesia, and adverse event incidence. RESULTS: The incidence of hypotension in Groups F and R was 73.3% and 96.7%, and the success rate of anesthesia was 93.3% and 66.7%, respectively. Compared with Group R, Group F showed superior results in terms of the incidence of hypotension (difference: -23.3%; 95% confidence interval [CI], -40.4 to -6.2; P (superiority 2-sided) < 0.05) and the success rate of anesthesia (difference: 26.6%; 95% CI, 7.5 to 45.7; P (superiority 2-sided) < 0.05). Group F experienced longer pain relief, required less vasopressors, and reported less transient chest tightness. No significant differences were observed in other outcomes. CONCLUSION: Low-dose ropivacaine combined with fentanyl remains a recommended choice for spinal anesthesia in cesarean sections, alongside carbetocin administration.