Studies on Lymphatic Drainage of the Peritoneal Cavity in Sheep

Abstract

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.

Fluid Kinetics in CAPD Patients during Dialysis with a Bicarbonate-Based Hypoosmolar Solution

“…In anesthetized and con scious sheep, direct measurement of the lym phatic flow has been done by cannulation of the thoracic duct and the efferent duct from the caudal mediastinal lymph node, but not of the right lymphatic duct. This approach has not solved the problem because the recovery of RISA in blood was 40-60% of the quantity disappearing from the peritoneal cavity, much higher than the 20% observed in hu Fluid Kinetics with a Hypoosmolar Blood Purif 1996:14:217-226 223 Solution mans [29][30][31][32], Also the amount of intraperitoneally administered RISA recovered in the circulation and in the drained lymphatic ves sels was always equal in this model to the amount lost from the peritoneal cavity during a 6-hour dwell period. Thus local accumula tion of the marker in the peritoneal cavity, as has been proposed as the cause of the discrep ancy between appearance and disappearance rates in humans, was not observed in these animals.…”

Pathways for Fluid Loss from the Peritoneal Cavity

“…macromolecular tracers (by monitoring the mass of i.p. tracer that en ters a given lymph compartment and dividing by the concentration of the tracer in the peri toneal cavity) [11], One drawback with this technique is that the cannulation process may affect the flow rate [ 12], Moreover, since can nulation is not ethically feasible in humans, use of this technique to estimate lymph flow during PD requires extrapolation from ani mal data.…”