The isolated perfused lung--a critical evaluation.

Recent refinement and application of the technique of perfusing isolated intact lung preparations from suitable experimental animal has enhanced our knowledge of the non-respiratory functions of the lung. The technique consists of perfusion with whole blood or constituted media via pulmonary artery or artificially ventilated lungs. Such preparations have been known to be especially useful for studies of uptake, metabolism and disposition of exogenous and endogenous substances. Recent advances in unilateral, split-lung perfusion in which left and right lungs are unilaterally perfused simultaneously have enabled investigators to maintain paired controls during perfusion. Such techniques are useful in the study of the interactions of endogenous and exogenous chemicals in the lung tissue. Differences between subcellular or lung slice preparations and intact lung perfusion are to be expected on the basis of distorting natural vascular and extra-vascular barriers in the case of in vitro preparations. Areas in which perfused lungs have not been extensively used include uptake and disposition of gases, solvents and vapors, effects of toxic chemicals on respiratory and non-respiratory functions of the lung and alteration of pulmonary mechanisms and hemodynamics in the presence of interacting chemical or physical stimuli. With suitable modifications, application of isolated perfused lung preparations for these investigations should be technically feasible in the future.