Effects of the phosphodiesterase III inhibitors olprinone, milrinone, and amrinone on hepatosplanchnic oxygen metabolism

Objective: To measure the hepatic venous oxygen saturation in patients afte r cardiac surgery and to compare the effects of olprinone (OLP), a newly sy nthesized phosphodiesterase III inhibitor, with those of milrinone (MIL) an d amrinone (AMR) on hepatosplanchnic oxygen dynamics. Phosphodiesterase III inhibitors are used to improve the hemodynamic state after cardiac surgery . However, the effect of these agents on the hepatosplanchnic circulation h as not been investigated thoroughly. Design: Prospective, randomized study. Setting: University hospital intensive care unit (ICU). Patients: Twenty-nine patients undergoing elective cardiac surgery. Measurements and Main Results: In each patient, a 7.5-Fr oximeter catheter was placed in the hepatic vein via the right femoral vein. Catheterization was completed before admission to the ICU, and the study was performed 8 to 24 hrs after surgery, after obtaining stable systemic hemodynamics in the ICU. The patients were assigned randomly to three groups, and they received one of three drugs for 2 hrs (OLP group, 0.3 mu g/kg/min of OLP; MIL group , 0.5 mu g/kg/min of MIL; AMR group, 10 mu g/kg/min of AMR). The authors di d not change the patient's hemodynamic interventions, including catecholami nes and vasodilators, throughout the study period. Arterial and hepatic ven ous blood gas data and hemodynamic data (via a pulmonary artery catheter) w ere obtained before and after drug infusion. Using these data, the authors calculated systemic oxygen delivery and consumption, the systemic oxygen ex traction ratio and the hepatosplanchnic oxygen extraction ratio, and the ch ange in hepatosplanchnic blood flow using Pick's equation. Although the increases in cardiac index were not significantly different am ong the three groups, hepatic venous oxygen saturation increased significan tly only in the CLP group (from 47.1% +/- 2.6% to 57.0% +/- 1.5% in the OLP group, from 48.4% +/- 2.3% to 50.9% +/- 2.6% in the MIL group, and from 49 .8% +/- 3.6% to 50.8% +/- 1.7% in the AMR group). The calculated hepatospla nchnic blood flow change was significantly larger in the OLP group than in the other groups (30.1% +/- 5.7% in the OLP group, 9.3% +/- 5.1% in the MIL group, and 2.6% +/- 6.5% in the AMR group). Conclusions: These results suggest that OLP enhances hepatosplanchnic blood flow and thus may be beneficial in protecting the hepatosplanchnic organs after cardiac surgery.