Table 2 Summary of Spinal Block Efficacy and Postoperative Analgesia by Ropivacaine Concentration.

From: Determining the optimal ropivacaine concentration for spinal anaesthesia during day surgery for anorectal procedures: a dose-finding study

Ropivacaine Concentration (%)

Successful Blocks(n/N)

Observed Response Rate

PAVA-Adjusted Response Rate

Pain Onset Time (min)

0.30% (4.50 mg, n = 10)

10/10

1.000

1.000

80.7 ± 9.2b

0.25% (3.75 mg, n = 11)

9/11

0.818

0.890

70.4 ± 20.1 ab

0.20% (3.00 mg, n = 26)

25/26

0.962

0.890

63.8 ± 16.4 a

0.15% (2.25 mg, n = 3)

1/3

0.333

0.333

26.0 1

  1. PAVA, Pool-adjacent-violators algorithm for dose–response modeling. MEC99 estimates are exploratory given sample‑size limitations; see Methods and Supplementary Materials for Monte Carlo simulation‑based precision assessment.
  2. Pain onset time analysis:
  3. Analyzed for 0.20%/0.25%/0.30% groups (One-way ANOVA: F(2,37) = 3.31, P = 0.037)
  4. Tukey post-hoc testing (a,bindicate pairwise differences at P < 0.05)
  5. Levene’s test confirmed variance homogeneity (P = 0.84)
  6. Single successful block at 0.15% (excluded from statistics)
  7. Lidocaine-supplemented cases excluded
  8. 0.15% group SD incalculable (n = 1)
Back to article page