Role of pulmonary lymphatics in chronic pulmonary edema.

• Clinically, the development of pulmonary edema is frequently associated with an elevation of left atrial pressure. However, overt pulmonary edema does not always occur with such pressure elevations, even when the plasma oncotic pressure is greatly exceeded. It is conceivable that a dilatation of the pulmonary lymphatic system might remove fluid from the lung and prevent, or delay, the development of overt pulmonary edema. In experimental studies on the dog, it has been demonstrated that lymph flow from the lungs increased with an acute elevation of the pulmonary venous pressure"; however, the quantity of lymph was small and apparently ineffective in preventing the development of pulmonary edema. The critical question, however, of the extent of the pulmonary lymph flow in chronic pulmonary edema remained unanswered. It was the purpose of the current study to determine what i*ole, if any, the lymphatics play in the prevention of chronic pulmonary edema.