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The purpose of this study was to examine the impact of low levels of residual renal function (RRF) on nutritional status in end-stage renal disease patients starting peritoneal dialysis (PD) at baseline and after a year on dialysis. We conducted a single center retrospective analysis of 116 patients who started long-term PD in a university teaching hospital from 1989 to 1998 and were followed for 1 year. Patients were divided into four equal groups according to their initial renal Kt/V(urea) (L/week) levels at the start of PD and followed for 1 year. There were no interventions. The relationship between dialysis adequacy (renal and total Kt/V(urea)) and nutritional status was studied at baseline and at 1 year. Baseline data for patients who survived were compared with the baseline data of those who died and with their own 1 year data. At baseline, the mean serum albumin (3.31 g/dl, p < 0.0001) and lean body mass (47.20% body weight, p < 0.04) of group 1 were significantly lower than in groups 2, 3, and 4. Levels of normalized protein equivalent of nitrogen appearance (nPNA) were significantly lower in group 1 than in groups 3 and 4 (p < 0.005). Although group 1 patients showed trends toward improvement in nutritional parameters, they never caught up with the other groups. At the end of 1 year, the lower total Kt/V(urea) in group 1, with the lowest RRF, was associated with the lowest mean values for nutritional status and the highest death rate. Comparison of baseline and 1 year data of survivors showed that nutritional status improved or remained stable in groups 3 and 4, who exceeded the minimum recommended adequacy targets as per Dialysis Outcome Quality Initiative criteria (mean 12 month total Kt/V(urea) 2.18 and 2.58, respectively). Comparison of baseline data of survivors and those who died showed that patients who died had lower mean values for serum albumin, nPNA, lean body mass, and body weight across all groups. Low RRF at the start of dialysis is associated with poor nutritional status. Also, patients who start dialysis with low RRF and poor nutritional status do not have significantly improved nutritional status even after 1 year on dialysis.

In nine patients on continuous ambulatory peritoneal dialysis (CAPD) who were in stable condition, the authors measured the effects of an extra daily exchange on small solute removals and clearances and the measured/predicted creatinine production (M/P). The goal was to evaluate the sensitivity of M/P to single exchange noncompliance. Daily collections of urine and dialysate were performed on the usual prescribed program and on the next day with an extra exchange of usual exchange volume. The average increase in drain volume of 26% was associated with an average increase in M/P of 6%. The maximum M/P increase was 15%; the percentage increase in M/P correlated inversely with renal creatinine clearance. Daily total urea clearance normalized to total body water by dialysis and renal function increased 12%. Extrapolating these findings suggests that an average patient with a baseline M/P near 1.0 and renal creatinine clearance of 5 ml/min would require more than 50% drain volume noncompliance to yield a M/P of 1.24 on the complaint day. A 50% noncompliance may not yield a M/P greater than 1.0 on the first compliant day if baseline M/P is less than 0.94. The authors suggest monitoring daily urine and dialysis creatinine output because M/P creatinine is relatively insensitive to noncompliance (particularly in patients with residual renal function) and because there are questions about the accuracy of predictions in patients with renal failure using formulae established in different populations. The authors recommend simply monitoring total daily creatinine output and establishing patients as their own controls. The authors provide a table for the interpretation of changes in creatinine output in conjunction with changes in other routinely monitored parameters.

Dialysate and blood leukocyte counts were measured during 130 episodes of peritonitis in 91 hospitalized patients on long-term peritoneal dialysis (CPD). The authors found that the blood/dialysate leukocyte count can be less than 1.0, and this is usually the case when dialysate leukocyte count exceeds 20,000/mm3. Dialysate leukocyte removal in a single 2 L drain bag can approach the leukocyte number in the entire circulating blood volume. Daily drainage can remove leukocytes in amounts exceeding the blood leukocyte pool 2 to 3 fold. The observed blood leukocyte counts throughout a range of 2,700 to 10,000 at dialysate leukocyte counts greater than 20,000 per mm3 may reflect: 1) leukocyte removal approaching maximum bone marrow output of leukocytes, and/or 2) increasing microcirculatory margination of leukocytes in those episodes of peritonitis associated with very high dialysate leukocyte counts.

A study was undertaken to evaluate the short-term reproducibility of peritoneal equilibration test (PET) results. Nine patients with end-stage renal disease undergoing continuous ambulatory peritoneal dialysis underwent PETs under similar conditions on 2 consecutive days. Dialysate samples were obtained at 0 hours, midcycle, and at the end of exchange. There were no significant differences between the mean ratios at 4 hours for creatine, urea nitrogen, potassium and protein, and glucose between PET 1 and PET 2. A standard PET is highly reproducible when repeated under similar conditions. Reproducibility is better for ratios of creatinine, glucose, urea nitrogen, and potassium than for protein.