Effects and arterial concentration of prostaglandin E1 during cardiopulmonary bypass.

The effects an infusion prostaglandin E1 (PGE1) on both haemodynamics and PGE1 arterial blood concentration during and after cardiopulmonary bypass (CPB) were studied in 15 patients (eight patients received PGE1 30 ng kg-1 min-1; seven served as controls and did not receive PGE1 administration). Mean arterial blood pressure and systemic vascular resistance were significantly lower in the PGE1 group than in the control group during CPB. There were no statistically significant differences between the two groups with regard to mean pulmonary-artery pressure, central venous pressure, and cardiac or perfusion index. The arterial blood concentration of PGE1 in the control group during CPB was about 50 pg ml-1. In the PGE1 group it increased rapidly after the beginning of CPB and reached a level of 1500 pg ml-1 at 60 min of CPB. After weaning off CPB, PGE1 concentration decreased rapidly to 70 pg ml-1 in spite of the continuous PGE1 infusion. It is concluded that the metabolism of PGE1 is strongly inhibited during CPB and the effects of PGE1 may be unexpectedly heightened. Therefore, the infusion rate of PGE1 during CPB should be 30 ng kg-1 min-1 or less in order to avoid severe hypotension.