Anesthesia & Clinical Research
Open Access

Abstract

Efficacy of low-dose hypobaric anesthetics in spinal anesthesia for cesarean delivery and comparison with other bupivacaine formulations

Zahra Reza Ghafari*, Ghassan Kloub, Ramesh Srigiri, Rasha Maryam, Rama Krishna

Background: Spinal anesthesia remains the technique of choice for elective cesarean delivery. However, conventional doses of intrathecal local anesthetics (e.g., 10 mg-12 mg of hyperbaric bupivacaine 0.5 %) are associated with a high incidence of maternal hypotension, nausea, vomiting, bradycardia, and consequent fetal perfusion concerns. Use of low-dose intrathecal local anesthetics (often <10 mg) either in hypobaric or marginally hyperbaric solutions has been proposed to mitigate these side effects while maintaining adequate surgical anesthesia. Objective: To review and compare the efficacy and safety of low-dose hypobaric (or marginally hyperbaric) intrathecal anesthetic techniques in cesarean delivery, with particular focus on bupivacaine formulations and resultant maternal/ fetal outcomes. Methods: A narrative review of Randomized Controlled Trials (RCTs), observational studies and recent systematic reviews/meta-analyses was conducted. Outcomes of interest included block adequacy, need for supplementation, hypotension incidence, vasopressor use, recovery times, maternal satisfaction, and neonatal outcomes. Comparisons across different bupivacaine doses, baricities, and adjuvant use (e.g., intrathecal opioids) were made. Results: Recent meta-analysis (17 trials, 1280 parturients) demonstrated that low-dose hypobaric local anesthetics (<10 mg bupivacaine/levobupivacaine; <15 mg ropivacaine) were associated with a significantly reduced risk of hypotension (RR~0.56, 95% CI 0.43-0.73) but a higher risk of requiring intraoperative analgesic supplementation (RR~3.13, 95% CI 2.14-5.59). Several RCTs confirm that doses as low as 7 mg hyperbaric bupivacaine (with intrathecal opioid) provide adequate surgical anesthesia while improving hemodynamic stability though may require epidural supplementation. PubMed+1 Comparisons of different baricity (marginally hyperbaric vs standard hyperbaric) also show lower cephalad spread and less hypotension with preserved efficacy. Conclusion: Low-dose intrathecal bupivacaine (or other local anesthetics) in hypobaric or marginally hyperbaric form for cesarean delivery can reduce maternal hemodynamic side?effects without meaningful compromise in surgical anesthesia provided appropriate adjuvants (intrathecal opioids) and readiness for supplementation. However, practitioner caution is required given the increased risk of block supplementation or failure, and the need for tailored dosing and monitoring

Published Date: 2026-05-12; Received Date: 2026-04-15