Lymphatic drainage of the peritoneal cavity in experimental ascites

Transport of labelled protein from the abdominal cavity by the thoracic duct and by the right lymph trunk was investigated in dogs with ascites due to inferior cava vein constriction and in control animals. The greater part of peritoneal fluid protein is transported in both ascites and under normal conditions by the lymphatics of the right side. The excess protein filtered from the liver sinusoids in venous stasis is transported by the thoracic duct. In this condition large amounts of fluid accumulate in the lymphatics in consequence of a relative obstacle to outflow at the veno-lymphatic junction. Thoracic duct drainage in experimental ascites leads to large fluid and protein losses and consequently to a reduction of inferior caval pressure and of capillary filtration in the liver. The intervention reduces ascites formation but does not influence the lymphatic absorption and transport of peritoneal fluid. Consequently, it is indicated only as a temporary measure, a preliminary to portocaval shunt operation, to reduce the increased sinusoidal and portal pressures. A cervical lympho-venous anastomosis reduces thoracic duct pressure by eliminating the obstacle to lymph flow. Accordingly, the intervention facilitates the return of excess lymph into the blood stream, and reduces fluid and protein leakage into the abdominal cavity from the liver.