Peritoneal Loss Research Articles

Serum glycated albumin and fructosamine in renal dialysis patients.

The effect of uraemia on protein glycation was studied by measuring glycated albumin and fructosamine in 50 non-diabetic dialysis patients (31 continuous ambulatory peritoneal dialysis, CAPD, 19 haemodialysis). After correction for serum albumin concentration, glycated albumin (g/100 g) was increased in the haemodialysis group (1.94 +/- 0.40) compared with both CAPD patients (1.46 +/- 0.37; p < 0.001) and controls (1.52 +/- 0.29; p < 0.001), but did not differ between CAPD patients and controls (p > 0.05). Serum fructosamine, corrected for either serum albumin or total protein concentration (mumol/100 g), was raised in CAPD (828 +/- 90, 386 +/- 41, respectively) and haemodialysis patients (802 +/- 123, 391 +/- 42, respectively) compared with controls (609 +/- 69, 332 +/- 27, respectively; p < 0.0001 in all cases), but did not differ between the two dialysis groups (p > 0.05). A single haemodialysis cycle had no effect on the measurement of glycated albumin or fructosamine (p > 0.05). The results confirm that glycated protein levels are generally raised in dialysis patients. In CAPD patients, altered albumin metabolism resulting from large peritoneal losses is likely to have caused a decrease in the amount of albumin glycated, an effect less apparent on the concentration of fructosamine because of the additional contribution of glycated globulins.

Evaluation of vitamin D-binding protein and vitamin D metabolite loss in children on continuous ambulatory peritoneal dialysis

We measured the serum concentration of vitamin D-binding protein (DBP) in children with chronic renal failure (CRF). We also evaluated the relationships between the peritoneal loss of vitamin D metabolites, DBP and albumin in nine children on continuous ambulatory peritoneal dialysis (CAPD). The serum levels of DBP in children with CRF were significantly higher than in normal children. The mean serum DBP level in CRF children undergoing CAPD was slightly lower than in CRF patients who were not on dialysis. In patients on CAPD, the peritoneal loss of 25-hydroxyvitamin D (25OHD) showed a significant positive correlation with the DBP concentration in the dialysate (r = 0.855, P less than 0.005). In contrast, the peritoneal loss of 1,25-dihydroxyvitamin D (1,25(OH)2D) showed a significant correlation with the loss of albumin in the dialysate (r = 0.779, P less than 0.01). The synthesis of 1,25(OH)2D3 is reduced in advanced renal failure, and the peritoneal losses of the active vitamin D sterols in patients on CAPD may aggravate this deficiency. We recommend that supplementation of active form of vitamin D, such as 1 alpha-hydroxyvitamin D3 or 1,25(OH)2D3, is important in CAPD patients, particularly those with elevated peritoneal loss of DBP and/or albumin.

Effect of Subcutaneous Administration of Recombinant Human Erythropoietin on Plasma Protein C, Protein S, and Antithrombin III Levels in Patients on Continuous Ambulatory Peritoneal Dialysis

The effect of subcutaneous administration of recombinant human erythropoietin (rHuEPO) on plasma natural coagulation inhibitors (protein C, protein S, and antithrombin III) was evaluated in 10 uremic patients on continuous ambulatory peritoneal dialysis (CAPD). These patients were commenced on a 16 week-course of twice weekly rHuEPO by the subcutaneous route. The hemoglobin increased significantly from 6.9 +/- 1.3 g/dl to 9.6 +/- 1.9 g/dl after subcutaneous rHuEPO treatment (p less than 0.01) at an average dose of 84 +/- 9 U/kg body wt/week. With rHuEPO therapy, a significant increase in platelet counts was observed, albeit within the normal range. A significant increase in the prothrombin time was demonstrated at 6 weeks after treatment and increased activated partial thromboplastin time was observed at 6 weeks and 16 weeks after rHuEPO administration although these measurements still remained in normal range. CAPD patients have comparable or even higher plasma levels of natural coagulation inhibitors compared with healthy controls supporting our previous findings that patients on CAPD have normal plasma levels due to an effective compensatory production despite peritoneal losses of these proteins with CAPD. No change in either the immunological or the functional activity of these natural coagulation inhibitors was demonstrated with rHuEPO therapy and clinical thrombosis was not observed during and after rHuEPO therapy. We conclude that there is no laboratory evidence of increased risk of thrombogenesis due to reduction of natural coagulation inhibitors with rHuEPO therapy.

Visceral Losses of Desflurane, Isoflurane, and Halothane in Swine

Percutaneous loss of inhaled anesthetics is small relative to their uptake. The minor nature of this loss results in part from the substantial barrier to diffusion posed by the skin. Pleural and peritoneal surfaces pose less effective barriers because diffusion distances are smaller than in the skin. Accordingly, we measured visceral loss to air of desflurane, isoflurane, and halothane from pleural and peritoneal surfaces in five juvenile swine. Pleural and peritoneal losses per percent end-tidal anesthetic correlated directly with the solubility of the anesthetic in blood or tissues. The total pleural losses for the first 30 min of anesthetic administration were desflurane, 1.22 +/- 0.22 mL (mean +/- standard deviation for the 30-min period); isoflurane, 2.34 +/- 0.52 mL; and halothane, 4.69 +/- 0.98 mL; respective peritoneal losses were 0.64 +/- 0.12 mL, 1.23 +/- 0.25 mL, and 2.69 +/- 0.57 mL. Pleural loss per unit time did not change with increasing duration of anesthesia, whereas peritoneal loss increased for all anesthetics. These visceral losses are greater than total percutaneous losses in humans given these anesthetics for the same period of time, but the loss of anesthetic by either route is too small to affect measurements of anesthetic kinetics or recovery.

Study on the assay of uremic protein-binding inhibitors: furan compound and hippuric acid

Plasma levels of 3-carboxy-4-methyl-5-propyl-2-furanpropionic acid (FA) and hippuric acid (HA) were studied in healthy subjects, uremic patients undergoing continuous ambulatory peritoneal dialysis (CAPD) and hemodialysis (HD). Analysis of FA and HA in the plasma were performed by gas chromatography with capillary column. The mean value of FA in HD patients (16.7 +/- 6.1 micrograms/ml) was significantly higher than these in healthy subjects (3.6 +/- 1.0 micrograms/ml) and in patients on CAPD (4.1 +/- 3.7 micrograms/ml) (p less than 0.01). HA levels in CAPD and HD groups were higher than those in healthy controls (2.4 +/- 0.8 micrograms/ml). In addition, the values in HD patients (46.7 +/- 53.5 micrograms/ml) were more increased than those in CAPD (18.5 +/- 16.5 micrograms/ml) (p less than 0.05). Approximately 95% of total FA and 25% of HA were bound to the plasma protein. However, the plasma level of HA was significantly reduced by HD therapy, whereas that of FA was not altered. In the previous study, it was described that no effect of HD on the percent of the binding of acid drugs to the plasma protein in the uremic plasma was observed. Therefore it is supposed that FA is more involved in the binding of drugs to the plasma protein in comparison with HA. The peritoneal losses of FA and HA in CAPD were 2.3 +/- 1.3 mg/day and 276 +/- 40 mg/day, respectively. As the duration of HD became longer, plasma concentrations of FA in HD patients were more increased. In general, they were maintained to be comparatively low in patients on CAPD.(ABSTRACT TRUNCATED AT 250 WORDS)

Enhancement of Ionized Calcium and 1,25-Dihydroxycholecalciferol Loss from Peritoneal Fluid during Peritonitis in Patients Treated with Continuous Ambulatory Peritoneal Dialysis

This study was to evaluate whether peritoneal loss of vitamin D metabolites during peritonitis leads to more depletion of 1,25-hydroxycholecalciferol [1,25(OH)2D3] and 25-hydroxycholecalciferol [25(OH)D] in continuous ambulatory peritoneal dialysis (CAPD) patients, especially in the high peritonitis occurrence group (HPOG). A series of ionized calcium, pH values, 1,25(OH)2D3 and 25(OH)D levels in dialysate during peritonitis were studied in 30 CAPD patients. In addition, bone mineral content (BMC) was determined during peritonitis. On the basis of peritonitis occurrence, 14 patients were in the low peritonitis occurrence group (LPOG) and 6 patients in the HPOG. Increase in peritoneal loss of ionized calcium, 1,25(OH)2D3, 25(OH)D and a decrease of pH value in dialysate may appear in the early period of peritonitis in both groups. When peritonitis occurs too frequently in a short period, the peritoneal membrane function cannot recover completely. Frequent peritonitis may impair peritoneal function and cause persistent loss of calcium. 1,25(OH)2D3 amd 25(OH)D loss is also higher in the HPOG than in the LPOG. The persistent loss of calcium, low plasma vitamin D levels and increased parathyroid hormone level with hyperparathyroidism in the HPOG are the important factors contributing to renal osteodystrophy. The lower BMC in the bone study confirmed this. Therefore, adequate calcium and vitamin D supplementation is necessary in the HPOG.

Kinetics of peritoneal protein loss during CAPD: II. Lipoprotein leakage and its impact on plasma lipid levels

We quantified the plasma levels and peritoneal loss of lipids and lipoproteins, and studied the composition of plasma and effluent lipoproteins in 16 patients on CAPD (5 females and 11 males, 18 to 76 years old). Five patients were studied prospectively (at 0, 1, 3 and 6 months) and 11 patients at 6 to 58 months on CAPD (N = 30). Elevated levels of plasma VLDL and reduced levels of plasma HDL were maintained in these patients throughout 58 months of CAPD, whereas the initially increased LDL levels showed a tendency towards normalization. All plasma lipoproteins (VLDL, IDL, LDL and HDL) were present in the peritoneal effluent. The lipoproteins isolated from plasma and peritoneal fluid shared a similar lipid and apolipoprotein composition. The peritoneal transport characteristics of plasma lipoproteins were similar to other plasma macromolecules. Their clearance correlated with their molecular mass, plasma concentration and dwell time, but was not affected by duration of CAPD treatment. The plasma lipid and lipoprotein levels were unaffected by the rate of glucose absorption. The peritoneal protein clearance correlated positively with plasma levels of triglyceride and LDL, and negatively with plasma HDL. An inverse correlation was observed also between plasma levels of HDL and its peritoneal clearance (r = -0.393, P less than 0.025, N = 30). The continuous peritoneal loss of HDL and the hypertriglyceridemia were found to contribute most to the persistent low plasma levels of HDL in CAPD patients, and thus may lead to the accelerated atherosclerosis observed in these patients.

Vitamin B6 requirements of patients on chronic peritoneal dialysis

Patients with chronic renal failure often develop vitamin B6 deficiency, which is of clinical concern because the multiorgan system manifestations are similar to those of uremia. Vitamin B6 deficiency in hemodialysis patients has been previously studied, but the need for daily pyridoxine supplementation in patients on chronic peritoneal dialysis (CPD) remains unclear. Therefore, we studied a group of 11 stable patients, nine on CAPD and two CCPD, to test for vitamin B6 deficiency and to establish daily requirements. Adequacy of vitamin B6 nutrition was assessed by measurement of plasma and dialysate effluent total vitamin B6 and pyridoxal 5'-phosphate (PLP), the latter using a very sensitive modification of the tyrosine apodecarboxylase enzyme assay. After four weeks without vitamin B6 supplements on a diet containing 1.3 +/- 0.2 mg vitamin B6/day (7.7 +/- 1.2 mumol/day), all patients had subnormal plasma PLP levels, 16 +/- 3 nmol/liter (nml 40 to 60), seven having a severe deficiency (less than or equal to 20 nmol/liter). Plasma total vitamin B6 levels (which includes non-PLP forms of the vitamin) were normal in all patients at baseline, 116 +/- 29 nmol/liter. Peritoneal losses were small, 8 +/- 2 nmol PLP/day and 545 +/- 61 nmol total vitamin B6/day. Supplementation with 5 mg/day oral pyrodoxine HCl for up to 16 weeks adequately repleted eight patients (65 +/- 7 nmol PLP/L), while three patients required 10 mg/day to achieve normal plasma PLP levels. During three episodes of peritonitis, dialysate losses of PLP did not increase.(ABSTRACT TRUNCATED AT 250 WORDS)

Vitamin D and Vitamin-D-Binding Protein Kinetics in Patients Treated with Continuous Ambulatory Peritoneal Dialysis (CAPD)

Serum and dialysate levels of 25-hydroxycholecalciferol (25-OHD3), 1,25 dihydroxycholecalciferol (1,25-(OH)2D3), and vitamin-D-binding protein (DBP) were measured in 14 patients undergoing continuous ambulatory peritoneal dialysis (CAPD). Serum levels of 25-OHD3 and DBP were within normal range (29.1 +/- 22.9 nmol/L and 5.9 +/- 1.1 mumol/L, respectively). Serum levels of 1,25-(OH)2D3 were subnormal in all (less than 16 pmol/L) but one. In 5 patients, dialysate concentrations of 25-OHD3 were 2.3 +/- 0.9 nmol/L, the rest had levels less than 1.0 nmol/L. Small quantities of 1,25-(OH)2D3 were found in the dialysate effluents. DBP could be detected in the dialysate in all patients (0.24 +/- 0.06 mumol/L). Mass transfer (MT) of 25-OHD3 and DBP were respectively -10.4 +/- 8.3 nmol/24 h and -1.46 +/- 0.46 0.46 mumol/24 h. Peritoneal clearances of 25-OHD3 and DBP were low (0.40 +/- 0.37 mL/min and 0.18 +/- 0.06 mL/min, respectively. We conclude that CAPD leads to losses of 25-OHD3 and DBP. However, the peritoneal loss of DBP is well compensated and does not result in serum deficiency. Serum 25-OHD3 levels did not correlate with time on CAPD.

Trimethoprim-Sulfamethoxazole Pharmacokinetics during Continuous Ambulatory Peritoneal Dialysis (CAPD)

Ten adult patients on continuous ambulatory peritoneal dialysis (CAPD) received one dose of trimethoprim-320 mg (TMP) and sulfamethoxazole 1600 mg (SMX) orally (p.o.), intravenously (i.v.), and intraperitoneally (i.p.) on three separate occasions to characterize the pharmacokinetics of both drugs. Concentrations of both TMP and SMX were measured in serum and dialysate by HPLC to 48 h. Half-life, total body clearance (TBC), and peritoneal clearance (PCl) were determined. The mean half-life of TMP was 28 h, while for SMX it was 12.5 h. Relative to the i.v. dose, the bioavailability following oral administration for TMP was 98% and 87% for SMX. Intraperitoneal bioavailability was 73% for TMP and 65% for SMX after a 4-h dwell. After 24 h, regardless of the route of administration, less than 3% of TMP and less than 6% of SMX appeared in dialysate. We conclude that peritoneal losses contribute insignificantly to TMP/SMX elimination during CAPD.

Plasma Levels of Pancreatic Secretory Trypsin Inhibitor in Relation to Amylase and Lipase in Patients with Acute and Chronic Renal Failure

Plasma levels of pancreatic secretory trypsin inhibitor (PSTI), lipase and amylase were measured in patients with chronic renal failure (CRF), patients undergoing regular hemodialysis treatment (RDT) or continuous ambulatory peritoneal dialysis (CAPD), patients with acute renal failure (ARF) and patients following successful cadaveric kidney transplantation. Plasma PSTI values were 9.2 +/- 0.8 ng/ml in controls (CO), 156.9 +/- 16.2 ng/ml in CRF patients, 257.6 +/- 22.3 ng/ml in RDT patients, 376.8 +/- 57.5 ng/ml in CAPD patients and 2,300 +/- 276.9 ng/ml in patients with posttraumatic ARF. RDT patients with malignant diseases displayed significantly higher PSTI values (1,014 +/- 148.7 ng/ml; p less than 0.01) than RDT patients without malignancy. Transplant patients with normal kidney function (creatinine 1.25 +/- 0.1 mg/dl) showed significantly lower PSTI values (16.7 +/- 2.1 ng/ml) than transplant patients with impaired renal function (creatinine 4.7 +/- 0.5 mg/dl; PSTI 72.8 +/- 11.8 ng/ml; p less than 0.01). Daily urinary excretion of PSTI increased from 26.7 +/- 3.1 micrograms (CO) to 551.8 +/- 54.8 micrograms in CRF patients. In CAPD patients, daily peritoneal loss of PSTI was 164.3 +/- 58.4 micrograms. Plasma PSTI values increased during hemodialysis with dialyzers made of cuprophan (317.0 +/- 32.6 vs. 422.0 +/- 46.2 ng/ml; p less than 0.05) and decreased with polysulfone dialyzers (226.6 +/- 19.9 vs. 86.6 +/- 18.1 ng/ml). There was no correlation between PSTI and urea, creatinine, lipase or amylase in each tested group. Our results document markedly elevated plasma PSTI values in all forms of renal insufficiency, suggesting extrapancreatic PSTI production and/or reduced renal elimination.

Improvement of Iron Utilization and Anemia in Uremic Patients Switched from Hemodialysis to Continuous Ambulatory Peritoneal Dialysis

Serum ferritin, hematocrit (Ht) and hemoglobin (Hb) were studied in seven patients treated with hemodialysis (HD) who later switched to continuous ambulatory peritoneal dialysis (CAPD). No iron supplements were given during the study. During the whole observation period (12 months on HD and 12 months on CAPD), there was a progressive decrease in serum ferritin during HD, accompanied by a progressive drop in Hb and Ht; on the contrary, on CAPD, Hb and Ht showed a sharp increase despite further ferritin reduction. The CAPD ferritin drop was not due to peritoneal loss of iron or ferritin, which appeared negligible. We propose that the increase in both Ht and Hb in CAPD is due to the removal of toxic factor(s) inhibiting erythropoiesis, which allow(s) increased iron utilization, and consequently a reduction in serum-ferritin levels. Anemia of chronic renal failure is a complex event to which many factors may contribute -reduced erythrocyte survival, hemolysis, iron losses from gastrointestinal leakage, reduced erythropoiesis, presence of inhibitors of erythropoiesis (1).

Prostaglandin-mediated loss of proteins during peritonitis in continuous ambulatory peritoneal dialysis

The loss of proteins into the dialysate and the peritoneal generation of the immunoreactive prostanoids PGE2, 6-keto-PGF1 alpha, PGF2 alpha, and TXB2 were studied in 12 patients undergoing continuous ambulatory peritoneal dialysis (CAPD) during 16 episodes of peritonitis and in inflammation-free periods. Protein permeability, defined as the ratio of dialysate/plasma protein (D/P), decreased with increasing molecular weight, independent of the condition of the peritoneum. With peritonitis a general rise of permeability was noticed for total protein (TP) and the individual proteins beta 2-microglobulin (beta MG), albumin (Alb), immunoglobulin G (IgG), and alpha 2-macroglobulin (alpha MG) (P less than 0.001). Simultaneously, an increase of dialysate prostanoids occurred with predominance of the vasodilative acting prostaglandins PGI2, determined as its metabolite 6-keto-PGF1 alpha, and PGE2 by factors of 8.4 and 9.7, respectively (P less than 0.001), in comparison to peritonitis-free control. In the early phase of peritonitis (0 to 12 hr after the onset of therapy) the augumented peritoneal prostaglandin synthesis correlated positively with the increased permeability of TP (r greater than or equal to 0.7446, P less than 0.01) and the individual proteins beta MG, Alb, IgG, and alpha MG (r greater than or equal to 0.5970, P less than 0.05). Inhibition of cyclo-oxigenase activity by local administration of indomethacin inhibited both the generation of 6-keto-PGF1 alpha and PGE2 by 39 and 42%, respectively (P less than 0.05), and the peritoneal loss of TP by 34% (P less than 0.05). In the absence of peritonitis indomethacin only diminished the synthesis of PGE2 whereas the generation of the other prostanoids remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Cefmenoxime kinetics during continuous ambulatory peritoneal dialysis.

The kinetics of the aminothiazolyliminomethoxy cephalosporin, cefmenoxime, were determined after a 30 min intravenous infusion of 15 mg/kg body weight in 6 adult subjects undergoing continuous ambulatory peritoneal dialysis. Concentrations of cefmenoxime in serum, urine and dialysate were determined by high-pressure liquid chromatography. The mean peak serum concentration was 92.8 +/- 11.6 micrograms/ml and the harmonic mean for the elimination half-life was 5.46 h. The volume of distribution at steady-state was 14.60 +/- 3.01 l/kg. Total body clearance of the drug was 31 +/- 7.7 ml/min with 8 +/- 5% and 5.75 +/- 2.72% of the administered dose being eliminated by renal and peritoneal clearance, respectively. Peritoneal clearance for all exchanges (n = 24) was 1.93 +/- 68 ml/min. These data suggest that peritoneal losses of this drug are minimal and doses conventionally employed in advanced renal failure can be utilized in the management of systemic infections.

Minerals and Bone-Modulating Hormones in Children on Continuous Ambulatory Peritoneal Dialysis

Peritoneal fluxes of minerals and bone-modulating hormones and their impact on corresponding serum levels and bone mineralization in 7 children on continuous ambulatory peritoneal dialysis (CAPD) were studied. Most mass transfer studies revealed modest losses of calcium into peritoneal effluents. Peritoneal losses of phosphorus and magnesium, although substantial, were not sufficient to normalize hyperphosphatemia and hypermagnesemia in most patients. Parathormone and vitamin D metabolites (25-hydroxyvitamin D and 1,25-dihydroxyvitamin D) were readily detectable in peritoneal effluents. Improved bone mineral content, by sequential densitometries, was associated with amelioration of hyperparathyroidism. These data suggest that CAPD in children induces an overall improvement of disturbed mineral metabolism; nevertheless, peritoneal losses of calcium and vitamin D metabolites must be considered and replenished appropriately.

The Durability of the Peritoneal Membrane

Severe membrane functional limitations with time on peritoneal dialysis are infrequently reported. Occasional reports where most patients were affected by peritoneal functional loss are in conflict with the good preservation of function reported by others. Such endemic distribution of structural and functional deterioration of the peritoneum should facilitate the search for etiologic factors. In the present state of ignorance it seems wise to treat infectious peritonitis promptly and aggressively, to support research in the area of membrane solution interaction and to carefully monitor the effects of chronic peritoneal dialysis on the peritoneal membrane. The most important determinant of the success of peritoneal dialysis in providing adequate therapy for chronic renal failure is the durability of the peritoneal membrane. Dobbie et al (I) have clearly stated the magnitude and severity of the problem in the following passage: “In view of the fact that most renal dialysis centres throughout the world are now embarking on a relatively new form of treatment for chronic renal failure -continuous ambulatory peritoneal dialysis, it is perhaps ironic that so little is known structurally of the tissue on which depends a life maintaining procedure and on which so many aspirations are now based.” Our ignorance of the peritoneal architecture is surpassed only by our poor understanding of the relationships between functional and structural changes. From the functional point of view, the peritoneal membrane includes the mesothelium which covers its free surface, the peritoneal interstitium, probably composed of an aqueous network bathing gels of mucosaccharides and collagen, and the microcirculation. Extensive research has been recently initiated to study the role of each of these components in transperitoneal transport and ultrafiltration and the effect of chemical and mechanical injury on the peritoneal membrane (1,2). The interest in investigating the factors responsible for altered states of solute and water transport during peritoneal dialysis has been stimulated by alanning reports suggesting functional deterioration of the peritoneal membrane system during chronic dialysis (3,4).

Losses of 1,25- and 24,25-dihydroxycholecalciferol in the peritoneal fluid of patients treated with continuous ambulatory peritoneal dialysis.

We measured peritoneal losses of the active vitamin D metabolites 1,25(OH)2D3 and 24,25(OH)2D3 in patients receiving continuous ambulatory peritoneal dialysis (CAPD). The serum concentration of 24,25(OH)2D3 was considerably lower than in hemodialysis patients. The serum concentration of 1,25(OH)2D3 was undetectable and rose to levels similar to those in hemodialysis patients only after loading with much higher oral doses of 1-alpha-vitamin D3 than those received by hemodialysis patients. Losses of both metabolites in peritoneal fluid were considerable, averaging approximately 6-8% of the plasma pool per day. These losses lead to low serum levels of these active vitamin D metabolites in CAPD patients, which may be an important factor in exacerbating renal osteodystrophy. Our results indicate the need for increased replacement doses of vitamin D metabolites in CAPD patients.

The Peritoneal Handling of Digoxin during CAPD

We measured digoxin concentrations in serum and dialysate from five digitalized patients on continuous ambulatory peritoneal dialysis (CAPD). Mean peritoneal clearance of digoxin was 3.6 ± 0.4 ml/min (± SEM). Mean mass transfer was 8.6 ± 0.6 μg/min. Our patients lost from 3.7 to 13.3% of their daily oral digoxin intake in dialysate. The mean dialysate over serum (D/S) digoxin ratio was 0.59 and fell between D/S creatinine (0.81) and D/S inulin (0.34). Between patients the range of this ratio was wide (0.25 to 0.90). We also measured serial digoxin dialysate concentrations during a six hour “dwell” in one patient and determined a D/S equilibration curve. After six hours dialysate digoxin approached a plateau near 0.5. Digoxin removal per week from dialysate was two to three times greater during CAPD than that reported from IPD. Peritoneal losses of digo xin cannot be predicted for an individual patient. In four of eight digitalized patients, the cardiac drug could be discontinued suggesting a beneficial effect of long-term CAPD in controlling congestive heart failure.