Peritoneal dialysis can maintain nitrogen balance with low Kt/V in anuric patients

A big concern for continuous ambulatory peritoneal dialysis (CAPD) is dialysis adequacy in anuric patients. Some studies have even suggested that CAPD patients should be transferred to hemodialysis when they become anuric in order to achieve adequate dialysis. In the present study, we tried to find out whether anuric patients can maintain nitrogen balance with standard or even lower dialysis dose.

This was a cross-sectional single-center study. Fifteen anuric CAPD patients were selected. Their 3-day dietary records were reviewed by a dedicated dietitian to calculate their energy, protein, and nitrogen intake (NI). Nitrogen removal (NR) from urine and dialysate was measured by Kjeldahl technique. Fluid status was evaluated by bioimpedance analysis. Subjective global nutritional assessment was used to evaluate nutritional status.

Among the 15 patients, 9 males and 6 females, mean age was 63.80 (31 - 77) years, dialysis duration 39.76 (6 - 127) months, body weight 58.70 ± 9.86 kg, and height 160.20 ± 7.93 cm. The mean dietary protein intake was 43.28 ± 7.57 g/day (0.80 ± 0.15 g/kg/d), total Kt/V was 1.59 ± 0.32 with dialysis dose of 7,904.00 ± 1,481.79 mL. However, they achieved neutral nitrogen balance (NI 6.92 ± 1.21 g/d vs. NR 6.83 ± 1.36 g/d, N balance 0.09 ± 1.00 g/d). All of them maintained good nutritional status (SGA "A", serum albumin 39.67 ± 3.58 g/L), and no symptom of nitrogen retention (serum urea 20.49 ± 3.06 mmol/L). Meanwhile, they achieved good volume control with a slightly low total fluid removal (704.00 ± 293.21 mL/d).

Our study suggested that anuric patients (even with low Kt/V) can achieve nitrogen balance and stay well-nourished with appropriate dietary protein intake.