Fig. 7.
The interaction between hydromorphone and sufentanil on the probabilities (P) for a numerical rating scale (NRS) pain rating under inspiration 4 or less (A) and 1 or less (B), respectively. Population predictions of hydromorphone alone are shown with solid lines. The dashed lines show the corresponding analgesic effect if a sufentanil concentration of 0.1 ng/ml is present.