PERITONEAL TRANSPORT DURING DIALYSIS WITH AMINO ACID-BASED SOLUTIONS

Objective: To evaluate the potential clinical role of amino acids as a n osmotic agent. Design: The peritoneal transport of fluid, amino acid s, and other solutes was investigated during a 6-hour single-cycle per itbneal dialysis with PDA 1% versus 1.36% glucose (n=6) or PDA 2.7% ve rsus 3.86% glucose solution (n=9). Patients: Fifteen stable nondiabeti c continuous ambulatory peritoneal dialysis (CAPD) patients. Results: The fractional absorption of the osmotic agents at 6 hours was higher with PDA 2.7% versus glucose 3.86% (p<0.005). The diffusive mass trans port coefficient, K-BD, calculated for a period of dialysate isovolemi a was higher with PDA 2.7% versus PDA 1% for essential, nonessential ( p<0.O05), and total(p<0.05) amino acids. The intraperitoneal volume-ov er-time curves and K-BD values for urea, creatinine, glucose, albumin, beta 2-microglobulin, and total protein did not differ between the am ino acid solutions and the corresponding glucose solutions. K-BD for u rea was significantly higher during the dwell with PDA 2.7% versus PDA 1% (p<0.05). Plasma amino acid concentrations increased substantially during the first 1-2 hours and then decreased gradually. Valine and m ethionine rose to 792% and 1119% of baseline values, respectively. Con clusions: We conclude that the peritoneal transport of fluid and inves tigated solutes, except amino acids, was not different with the amino acid solutions compared with the corresponding equimolar glucose solut ions. However, ultrafiltration tended to be lower with amino acid solu tions. Furthermore, the fractional absorption of amino acids and K,, v alues for amino acids was higher with PDA 2.7% versus PDA 1%, suggesti ng an effect of the hypertonic amino acid solution on the peritoneal m embrane transport properties. Also, the hypertonic PDA 2.7% solution y ielded nonphysiologically high plasma levels of several amino acids. W e therefore consider this solution not to be safe enough for longterm clinical use.