Some Observations on the Role of the Lymphatics in Experimental Acute Pulmonary Edema

Abstract

Lymph was collected from the right duct and thoracic duct of 13 dogs in which acute pulmonary edema was produced by partial obstruction of the left atrium by means of a balloon. Elevation of left atrial pressure to 30 mm. Hg resulted in an increase in thoracic duct flow within 30 minutes, followed by an increase in right duct flow within the next 15 minutes. Critical pulmonary edema became manifest approximately 30 minutes after the onset of increased right duct flow, and the dogs died in pulmonary edema approximately 90 minutes after inflation of the left atrial balloon, unless the left atrial pressure was reduced. The per cent of fluid in serial lung biopsies increased in the first biopsy taken 15 minutes after the elevation of left atrial pressure to 30 mm. Hg, and the increase was sustained, resulting in engorgement of the lungs unless the left atrial pressure was decreased. The small absolute increase in lymph from the right duct suggests that the lymphatics are unable to function significantly to relieve the pulmonary edema produced in the.se acute experiments, resulting in an overflow of fluid into the tracheobronchial tree. C41utamic oxalacetic transaminase showed marked increases in the lymph from the right duct but only modest increases in the lymph from the thoracic duct throughout the experiments. Pyruvic transaminase in lymph from the right and thoracic ducts was relatively unchanged.