Pulmonary effects of blood replacement with a perfluorochemical emulsion followed by exposure to 85% oxygen or air

Perfluorochemical emulsions (PCE) have been used as blood substitutes because of their high solubility coefficient for oxygen. However, concerns for their clinical use include both the hyperoxia required by PCE to improve oxygen delivery to tissues and the effects of PCE on lung tissue. We addressed 3 questions: (1) What are the combined effects on the lungs of PCE blood replacement and hyperoxia? (2) Does reduction of circulating white cells by PCE blood replacement modify the injurious effects of hyperoxia? (3) Does PCE alone alter the lungs? Adult rats received either partial or complete PCE blood replacement or no PCE and were then exposed to 85% oxygen for 5 days. Other rats received partial PCE or no PCE and breathed air for 5 days. Morphometric and morphologic analyses demonstrated that lung injury was primarily caused by hyperoxia, independent of PCE treatment. Statistical analyses of the data indicated no synergistic effects between PCE and hyperoxia; furthermore, transient reduction of blood inflammatory elements by PCE blood replacement did not modify the extent of injury that occurred later. Importantly, however, rats that received partial PCE and air exposure were virtually identical to those that received no PCE and air exposure. Five days after blood replacement, PCE components were most often seen within alveolar and interstitial macrophages and infrequently within endothelial and epithelial cells. Although PCE itself may have produced functional alterations in lung cells, direct effects were not morphologically evident. Our results suggest that, if PCE are used at moderate FIO2, such as 0.6 or less, structural changes in the lungs could be minimized.