Figure 49-28 Schematic diagram of the determinants of blood flow distribution during one-lung ventilation. The major determinants of blood flow to the nondependent lung are gravity, surgical interference with blood flow, amount of nondependent lung disease, and magnitude of nondependent lung hypoxic pulmonary vasoconstriction. The determinants of dependent lung blood flow are gravity, amount of dependent lung disease, and dependent lung hypoxic pulmonary vasoconstriction. RV, right ventricle. (From Benumof JL: Anesthesia for Thoracic Surgery. Philadelphia, WB Saunders, 1987.)