EFFECT OF BLOOD AND ALBUMIN ON PULMONARY-HYPERTENSION AND EDEMA IN PERFUSED RABBIT LUNGS

Perfusate composition may alter pulmonary hemodynamics and edema forma tion in perfused lungs. Perfusion for 3 h with Krebs-Henseleit solutio n with 3% bovine serum albumin did not produce pulmonary hypertension, pulmonary edema (assessed by lung wet-to-dry wt ratio), or increased macromolecular permeability (assessed by I-125-albumin uptake). Additi on of blood to hematocrit levels of 10 or 20% resulted in pulmonary hy pertension during the final hour of perfusion but not pulmonary edema or increased macromolecular permeability. Pulmonary hypertension durin g blood perfusion was primarily due to increased precapillary resistan ce. Perfusion with buffer solution without albumin produced edema and increased macromolecular permeability but not pulmonary hypertension. In lungs perfused with blood (20% hematocrit), thromboxane B-2 levels increased in parallel with the pulmonary hypertension, and inhibition of cyclooxygenase or thromboxane synthase with indomethacin or dazmegr el prevented pulmonary hypertension. Perfusion with leukopenic blood ( from prior nitrogen mustard administration or from filtration) also pr evented pulmonary hypertension. We conclude that blood perfusion produ ces pulmonary hypertension via thromboxane Az generation, which depend s on leukocyte activation, and that perfusion with buffer solutions wi thout albumin produces edema and increased permeability without pulmon ary hypertension.