Studies on Lymphatic Drainage of the Peritoneal Cavity in Sheep

In the sheep, it is possible to cannulate several of the lymphatics that drain the peritoneal cavity and assess lymphatic drainage of this serous space directly. Indwelling catheters were placed in the caudal mediastinal and thoracic ducts. The right lymph duct could not be cannulated. Lymphatic drainage of the peritoneal cavity based on the movement of 125I-albumin from the cavity into the lymph compartments was not affected by the osmolality of the dialysate but was markedly altered by anesthesia. In addition, lymphatic drainage was assessed from the disappearance of instilled 125I-albumin from the peritoneal cavity and from the appearance of intraperitoneally administered 125I-albumin in the bloodstream and compared with data from the cannulated preparations. Lymph flows derived from tracer movement into the cannulated lymph compartments and from the appearance of tracer in the bloodstream were very similar. However, calculations of lymph flows based on the disappearance of tracer from the peritoneal cavity appeared to overestimate lymphatic drainage.