Fig. 2.
Dose–response curves at 15 min for (A) fentanyl and (B) bupivacaine derived by nonlinear regression using a hyperbolic model. The derived dose–response models for individual drugs (doses in micrograms) were: Effect = 100 × dose / (13.82 + dose) for fentanyl, and Effect = 100 × dose / (1,590 + dose) for bupivacaine.