Enhanced ultrafiltration in rabbits with bicarbonate glycylglycine peritoneal dialysis solution.

Objective: The aim of the study was to investigate net ultrafiltration (NUF) with a new bicarbonate glycylglycine (BiGG) peritoneal dialysis solution compared to the standard lactate (La) solution.

Design: In six groups of 12 normal rabbits each we measured NUF after a 2-, 4-, and 6-hour peritoneal dialysis with a BiGG solution (pH 7.35) and a standard La solution (pH 5.5) of similar glucose, electrolyte, and osmolality formulation. Furthermore, we studied the phosphatidylcholine concentration in the effluent of the two solutions.

Results: NUF volume was significantly greater with the BiGG rather than with the La solution by approximately 15% (p < 0.05), 30% (p < 0.01), and 40% (p < 0.005) at 2, 4, and 6 hours, respectively. The glucose absorption rate was greater with the La solution than with the BiGG solution, but the difference was significant only at 2 hours (p < 0.05). pH was increased in the La solution from its initial value of 5.5 to 7.18, 7.32, and 7.40 at 2, 4 and 6 hours, respectively, while it remained almost unchanged in the BiGG solution. Phosphatidylcholine (PC) in the peritoneal effluent was significantly higher in the BiGG solution in all instances (p < 0.0001).

Conclusion: It is concluded that the BiGG solution, which has a stable pH, 7.35, due to the potent buffering capacity of bicarbonate and glycylglycine, enhances peritoneal NUF by maintaining a higher osmotic gradient and retarding lymphatic absorption through an increase in PC concentration in the peritoneal cavity.