Novel low na peritoneal dialysis solutions designed to optimize na gap of effluent: Kinetics of na and water removal

Background: An imbalance between sodium intake to and excretion from the body contributes to overhydration in peritoneal dialysis (PD) patients. Novel low Na solutions were developed based on the concept of optimizing the Na gap of effluent to achieve better Na balance. The present study investigated Na and water removal by those solutions. Methods: Compositions of low Na (LS) and standard Na (SS) solutions were as follows: Na 133, 126, and 118 mEq/L with respective corresponding glucose concentrations of 0.9%, 1.6%, and 2.5% in LS(90), LS(160), and LS(250) solutions; Na 135 mEq/L with glucose 1.35% and 2.5% in SS(135) and SS(250) solutions respectively. Based on the status of their daily PD prescriptions, respective LS solutions were assigned to 41 patients as follows: LS(90) or LS(160) for SS(135) solution, and LS(160) or LS(250) for SS(250) solution. Results: In the 4-hour dwell, no differences were found in Na removal between LS(90) and SS(135), whereas Na removal by LS(160) and LS(250) was significantly increased compared to SS(135) and SS(250) (p < 0.05 respectively). The Na gaps of the 3 respective LS solutions were significantly less than those of controls (p < 0.05 respectively). With 1-day full-time use of LS solutions, no significant changes were found in daily water removal compared to controls, while Na removal was significantly increased in LS solutions (p < 0.05), with conversion to a negative Na gap in total daily effluent. Conclusion: The low Na solutions used in the present study facilitated Na removal by reducing the Na gap. This characteristic is expected to achieve better Na balance in PD patients with excess body fluid retention.