Authors: Vakiarou F et al.
Published in: Cureus, September 2025. DOI: 10.7759/cureus.91480
Summary:
This systematic review evaluated all randomized controlled trials that compared different doses of intrathecal ropivacaine for cesarean delivery. Across 10 trials and 756 patients, the authors found substantial heterogeneity in study design, dosing regimens (4 mg to 25 mg), and definitions of “successful anesthesia,” which made a meta-analysis inappropriate. Reported ED50 values ranged from 6.1 to 16.7 mg, while ED95 values ranged from 11.4 to 26.8 mg. However, the highest values came from a study that assessed block success unusually late (30 minutes), making them less clinically applicable.
The best-designed studies—those with clear dosing arms, consistent timing of assessment, and robust methodology—clustered around an ED50 of 8–10 mg and an ED95 of 12–15 mg. Sensory block height varied across trials, but most defined success at T4–T7 with no need for supplemental anesthesia. Motor block reporting was inconsistent, but higher doses were associated with longer and denser motor block. Hypotension occurred more frequently with higher doses, with one study reporting a rate as high as 55% in the highest-dose arm.
The review also emphasized gaps in the literature. Trials used different dermatomal targets, different block assessment times, and lacked standardized criteria for inadequate anesthesia. Most studies were conducted in Asian populations, raising concerns about generalizing doses to taller Western populations where spinal spread may differ.
Overall, the review concludes that 12–15 mg of intrathecal ropivacaine is the most consistently effective dose range for cesarean delivery, producing reliable surgical anesthesia with manageable hemodynamic effects. More standardized research is needed, especially in populations with greater height variability.
What You Should Know:
• Most reliable ED50: 8–10 mg.
• Most reliable ED95: 12–15 mg.
• Higher doses increase hypotension risk without clear benefit.
• Study heterogeneity (definitions, dermatomes, timing) limits firm universal guidance.
• Nearly all trials involved relatively short women; taller Western populations may require adjusted dosing.
• Best-quality trials support 12–15 mg as the optimal practical dose range.
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