EFFECT OF PHOSPHATIDYLCHOLINE ON LYMPHATIC DRAINAGE AND FLUID LOSS FROM THE PERITONEAL-CAVITY OF SHEEP

Effect of phosphatidylcholine on lymphatic drainage and fluid loss fro m the peritoneal cavity of sheep. The purpose of this investigation wa s to test the hypothesis that phosphatidylcholine enhances net ultrafi ltration by decreasing lymphatic drainage of the peritoneal cavity. Tw elve sheep were used in this study. Six animals received 50 ml/kg intr aperitoneal infusions of Dianeal(R) 4.25% (490 mOsm/liter) and six rec eived similar volumes of premixed phosphatidylcholine-Dianeal(R) (510 mOsm/liter). Labeled albumin (25 mu Ci I-125-human serum albumin) was added to the dialysate as a lymph flow marker. Lymph drainage of the p eritoneal cavity was estimated from the appearance of the intraperiton eally administered tracer in the blood. Net ultrafiltration was signif icantly enhanced by phosphatidylcholine at each hour up to 6 hours pos t-infusion, and over this period reached 30.3 +/- 3.8 ml/kg in the pho sphatidylcholine animals compared to 12.2 +/- 2.1 ml/kg in the control group. Phosphatidylcholine treatment decreased the volume removed by lymphatics; by six hours 5.5 +/- 1.1 ml/kg in the animals receiving ph osphatidylcholine, and 10.3 +/- 1.0 ml/kg in the control group was dra ined as lymph. Fluid loss (estimated from the tracer disappearance fro m the peritoneal cavity) was slightly less in the phosphatidylcholine- treated animals, averaging 15.8 +/- 1.6 in this group versus 16.8 +/- 1.7 ml/kg in the control sheep. However, these differences were not si gnificant. Phosphatidylcholine significantly increased transcapillary ultrafiltration (estimate of volume movement into peritoneal cavity wi thout fluid loss) from 27.6 +/- 1.5 ml/kg in the controls to 43.8 +/- 3.4 ml/kg in the animals receiving phosphatidylcholine. In summary, th e inhibitory effect of phosphatidylcholine on lymph drainage may not c ontribute significantly to the enhanced net ultrafiltration, since tot al fluid loss from the peritoneal cavity was approximately the same in phosphatidylcholine-treated and untreated groups. We conclude that th e main effect of phosphatidylcholine in sheep is to facilitate the mov ement of liquid from the blood into the peritoneal cavity.