Analgesic Efficacy of Intrathecal Hyperbaric Bupivacaine Alone versus Pre-mixed and Sequential Fentanyl-Bupivacaine for Caesarean Section: A Randomized Controlled Trial

Belete Destaw^1*, Daniel Kebede², Geracho Garola³, Anteneh Gashaw², Yayeh Adamu¹

¹Department of Anaesthesiology, College of Medicine and Health Sciences, Dilla University, Dilla, Ethiopia

²Department of Midwifery, College of Medicine and Health Sciences, Dilla University, Dilla, Ethiopia

³School of Medicine, College of Medicine and Health Sciences, Dilla University, Dilla, Ethiopia

*Corresponding Author Belete Destaw, Department of Anesthesiology, College of Medicine and Health Sciences, Dilla University Dilla, Ethiopia, Email: baleanst@gmail.com

Abstract

Introduction: The optimal method for administering intrathecal fentanyl with hyperbaric bupivacaine for caesarean sections remains unclear. This study evaluated the analgesic effectiveness of sequential versus premixed intrathecal fentanyl, as well as bupivacaine alone, in women undergoing elective caesarean sections.

Method: A double-blind randomized controlled trial was conducted with 192 ASA II parturient women undergoing elective caesarean sections under spinal anesthesia at Dilla University Teaching Hospital in Ethiopia. The study ran from May 2021 to October 2022. Participants were randomly assigned to three groups: Group B received 12.5 mg of hyperbaric bupivacaine alone; Group M received 10 mg of hyperbaric bupivacaine mixed with 25 µg of fentanyl; and Group S received 10 mg of hyperbaric bupivacaine followed by 25 µg of fentanyl. The primary outcome was postoperative pain measured by the visual analog scale (VAS). Secondary outcomes included time to the first request for analgesics, block characteristics, analgesic use, adverse events, and neonatal outcomes.

Results: VAS pain scores were significantly lower in Groups S and M than in Group B at several postoperative time points (p < 0.05). However, no consistent statistically significant difference was observed between Groups S and M. The mean time to the first analgesic request was significantly longer in Group S (248 ± 42.6 min) and Group M (229 ± 35.1 min) than in Group B (178 ± 34.2 min) (p < 0.001). The duration of motor block was longer in Group S (p = 0.006). Hypotension occurred more often in Group M than in Group S (p = 0.040). Neonatal APGAR scores were similar across the groups.

Conclusion: Intrathecal fentanyl improved postoperative analgesia compared with bupivacaine alone. However, differences between sequential and pre-mixed administration techniques were modest and of uncertain clinical significance. Further multicentre studies are recommended.

Trial Registration: Pan African Clinical Trial Registry: PACTR202205853184065 (retrospectively registered)