Effect of exchange transfusion with a red blood cell substitute on neonatal hemodynamics and organ blood flows

The present study was designed to evaluate the effect of a perfluorocarbon erythrocyte substitute on hemodynamics in the newborn lamb. Isovolumic double volume exchange transfusions were performed with perfluorocarbon emulsion (FC-43) on lambs who were ventilated to maintain normal acid base status. Hematocrit, fluorocrit, viscosity, arterial gas tensions, mean arterial pressure, and heart rate were determined before (control) and after (exchange) exchange transfusion. A radiolabeled microsphere technique was used and cardiac output, organ blood flow, organ vascular resistance, and oxygen delivery were calculated. As the hematocrit and viscosity decreased and the fluorocrit increased, there was a significant increase in PaO₂ as well as a significant decrease in A-a gradient and oxygen content. There was no significant change in the acid-base status or the hemodynamic profile (heart rate, stroke volume, cardiac output, and mean arterial pressure). Blood flow to the heart and brain showed a significant increase, whereas flow to the cortex of the kidney showed a significant decrease. There was no significant change in flow to the gastrointestinal tract. Organ vascular resistance in the brain significantly decreased, increased in the kidney, and showed no significant change in the heart and gastrointestinal tract. Oxygen delivery significantly decreased in all organs except the heart. These data suggest that perfluorocarbon emulsions can acutely maintain hemodynamic stability in the newborn lamb and that the intrinsic properties of perfluorocarbons allow for the preservation of adequate oxygenation and acid-base status.