Figure 4. Comparison of size of the initial area blocked in cm²(+/− SD) for an intercostal block with doses of 8, 20, 40, and 80 mg/kg bupivacaine microspheres and bupivacaine-dexamethasone microspheres (A). Points are mean +/− SD; n = 5 sheep per dose-group. The same data are plotted as total dose of microspheres per animal (mg) to allow comparison of drug efficacy based on absolute dose administered (B). Initial areas blocked correlated significantly with increasing doses of bupivacaine-dexamethasone microspheres, but not bupivacaine microspheres. The two microsphere preparations did not differ with respect to the initial area anesthetized (P = not significant; Student's t test).