Figure 3

Dose–response curve for ropivacaine plotted from probit analysis. The minimum local analgesic volume of 0.25% ropivacaine for fascia iliaca compartment block was 15.01 ml (95% confidence interval CI − 6.53 ml ~ 22.99 ml), and the 95% effective volume was 26.99 ml (95% confidence interval CI 20.54 ml ~ 84.09.