Effect of prostaglandin E1 and nitroglycerin on portal venous flow during hypothermic extracorporeal circulation: Assessment by transesophageal echography

Background: Although several vasodilators are used to control vascular resi stance during cardiac surgery, their effects on splanchnic circulation duri ng extracorporeal circulation are unknown. We designed the present noninvas ive study to evaluate the effect of prostaglandin E1 and nitroglycerin on p ortal venous flow during extracorporeal circulation using transesophageal e chography. Methods: We included 26 patients undergoing cardiac surgery with moderate h ypothermic extracorporeal circulation in this study. After obtaining hemody namic stability under extracorporeal circulation, we measured portal venous diameter, mean flow velocity and the velocity time integral using transeso phageal echography and calculated portal venous flow The patients were assi gned to two groups where either prostaglandin E1 (N=13) or nitroglycerin (N =13) was administered intravenously to maintain perfusion pressure at the l evel of 70 mmHg. We measured the same parameters 20 and 40 min following ad ministration of the drug. Results: Visualization of the portal vein was obtained by transesophageal e chography in anesthetized patients. Calculated portal venous flow significa ntly increased in the prostaglandin E1 group, while it did not alter in We nitroglycerin group. Conclusion: The present results indicate that transesophageal echography ma y be a feasible tool to assess portal venous flow, and that prostaglandin E 1 may improve the blood distribution to the splanchnic area and the liver d uring hypothermic extracorporeal circulation.