Peritoneal Dialysis International: Journal of the International Society for Peritoneal Dialysis

To perform a cross sectional analysis in 71 patients on continuous ambulatory peritoneal dialysis (CAPD) to identify significant correlations of weekly small solute clearances and indices of nutritional status with each other and with patient demographics and other commonly monitored clinical and laboratory parameters.

This was a retrospective, cross sectional analysis in 71 patients on CAPD from less than 1 to 105 patient-months (average, 20 months).

An outpatient CAPD program.

All patients on CAPD in our program at the time of the study willing to undergo the clearance and nutritional status measurements.

No interventions other than the monitoring of their status.

Weekly small solute clearances, dietary protein intake, serum albumin, lean body mass, net protein catabolic rate, and urinary and dialysate nitrogen.

Weekly K/V urea (weekly urea clearance normalized to total body water) of at least 1.7 and weekly total creatinine clearances (liter/week/1.7 m2) of at least 50 are associated with net protein catabolic rates (PCR) greater than 0.9 g/kg of normalized body weight in average CAPD patients. K/V urea and net PCR correlate significantly with serum albumin. High transporters identified by the peritoneal equilibration test have greater albumin losses and lower serum albumin concentrations. Estimates of lean body mass correlate significantly with serum albumin and net PCR; lean body mass correlates significantly and inversely with age.

Greater small solute clearances are associated with better nutritional status.

To determine whether estimates of daily dialysis clearance of creatinine and urea, based on data from the 4-hour peritoneal equilibration test, correlate well with daily dialysis clearance measured by 24-hour dialysate collection in chronic ambulatory peritoneal dialysis patients.

Prospective study in which each subject collected all dialysate from a 24-hour period and then immediately thereafter underwent a standard peritoneal equilibration test (PET). Daily clearances of creatinine and urea were calculated from 24-hour dialysate collections by standard methods and then were compared with several estimates of 24-hour clearance based on PET data.

Single peritoneal dialysis unit of a university teaching hospital.

Thirty-six stable patients on continuous ambulatory peritoneal dialysis (CAPD).

The estimated values for daily dialysis clearance both overestimated and underestimated the measured 24-hour clearance. The correlation coefficient between the extrapolations and the actual 24-hour clearances ranged from 0.63–0.68. The range of discordance for daily creatinine clearance was from -2530 mL/dayto +2199 mL/day. For daily urea clearance, the range of discordance was from -21 03 mL/ day to +1940 mL/day. The peritoneal membrane transport characteristics of the individual patient did not predict whether the extrapolation overestimated orunder estimated the measured daily clearance.

Extrapolation of PET data is not a reliable method to estimate the dose of dialysis delivered to the patient. A 24-hour collection of dialysis is necessary for this determination.

To develop a formula that would permit a rapid and simple calculation of required dialysate volume needed to provide a predetermined daily creatinine clearance.

Prospective study of peritoneal dialysis patients followed for 6 months.

A primary care teaching hospital in New York.

Twenty-six patients beginning peritoneal dialysis entered and completed the study.

By employing each patient's measured peritoneal equilibration test (PET) and a standard clearance formula, a patient-specific treatment protocol (PSP) was calculated. The PET 2-hour DIP croat was used for continuous cycling peritoneal dialysis (CCPD) and the 4hour DIP patients on continuous ambulatory peritcornoeal dialysis (CAPD) to determine a PSP that would provide a minimum of 6 L of creatinine clearance daily.

Patients were followed for 6 months to assess the ability of this approach of maintaining acceptable levels of blood urea nitrogen, creatinine, albumin, and hematocrit over the 6–month period of observation.

Our study of 26 patients revealed that only 6 patients (23%) could be treated with the standard prescription of 8 L/day on CAPD. The remaining 77% of our patients required 9–13 L/day for CAPD and 12–21 L/day for CCPD. All patients were free of uremic symptoms and demonstrated acceptable biochemical parameters over a 3–6 month period of observation.

A patient-specific protocol utilizing individually derived PET data provides an acceptable and easy to calculate initial treatment prescription for each patient that avoids the necessity for trial and error that has heretofore been employed.

We hypothesized that the infection rates and organisms would differ in long-term peritoneal dialysis (PD) patients versus those who died or transferred to hemodialysis during the first 4 years on PD.

Data on PD-related infections and outcome were collected from 1979 to 1991 (prospectively since 1982).

The patients were followed at University and Veterans Administration dialysis centers.

All patients on continuous ambulatory peritoneal dialysis (CAPD) or continuous cycling peritoneal dialysis (CCPD) for 4 years or more (n=43) were compared to those patients who died or transferred to hemodialysis prior to 4 years on PD (n=213).

Infection rates due to various microorganisms and reasons for transfer to hemodialysis were examined.

Peritonitis rates were 1.2/year versus 0.8/year (p<0.001) in patients on peritoneal dialysis less than 4 years compared to those on 4 years or more, respectively, a difference due to S. epidermidis (0.32/year vs 0.20/year, p=0.0001) and gram-negative rods other than P. aeruginosa (0.15/year versus 0.06/year, p<0.001). Exitsite infection rates were 1.2/year versuss 0.7 /y (p<0.0001) in the patients on less than 4 years compared to those on 4 years or more, respectively, a difference in part due to S. aureus (0.45/year vs 0.3/year, p<0.001) and other gram positive organisms (0.28/year vs 0.1 0/year, p<0.001). The rates of infections that were similar in the two groups were tunnel infections (0.2/year), P. aeruginosa infections, and S. aureus peritonitis (0.18/year vs 0.14/year, p=0.09). S. aureus was the most common cause of exit-site and tunnel infections in both groups. Forty-two percent of the patients on PD 4 years or more subsequently transferred to hemodialysis, most often due to infections, especially S. aureus.

Although infection rates are lower in patients on peritoneal dialysis 4 years or more, S. aureus and P. aeruginosa continue to account for a high proportion of the infections. Improvement in technique survival will require prevention of these infections.

Chronic tunnel infections often necessitate the removal of the continuous ambulatory peritoneal dialysis (CAPD) catheter. Most published studies advocate postponing the insertion of a new catheter for several weeks. For young children it will be particularly difficult to wait this length of time, since vascular access may be cumbersome, and hemodialysis may not be well tolerated. The present study describes the results of the simultaneous removal and replacement of the CAPD catheter. .Design: Twenty-three Toronto Western Hospital II catheters were inserted in 17 children because of infectious complications (21 chronic tunnel infections; 2 recurrent peritonitis) in a single operation under appropriate antibiotic prophylaxis. The new catheter was inserted at the contralateral side of the abdomen with the deep cuff in the midline, using the same entrance to the peritoneal cavity. Dialysis was resumed immediately after the operation.

A university pediatric dialysis unit.

Seventeen children (mean age 3.7 years; range 1.0–8.5 years) were studied. In this group 23 catheters were replaced.

In four cases a relapse of the tunnel infection was observed within 3 months. All other cases remained free of infection for a period of at least 6 months. The main causative microorganism was Staphylococcus aureus (15 occurrences).

It is not necessary to interrupt peritoneal dialysis for the replacement of a CAPD catheter because of infectious complications.

To study the mechanism(s) of potassium transport into human mesothelial cells (HMC) exposed to osmotic solutes.

Using potassium analog 86Rb, we evaluated its intracellular transport through three pathways: 1. blocked by ouabain; 2. blocked by furosemide but not by ouabain; 3. blocked by neither furosemide nor ouabain. Experiments were performed in a normotonic medium (control) or in a medium supplemented with osmotic solutes (glucose, glycerol, mannitol). Both the acute and chronic effects of osmotic solutes on potassium transport were studied.

The acute exposure of mesothelial cells to osmotic solutes modifies the intracellular transport of potassium through all studied channels, and the effect is specific for every solute. In mesothelial cells exposed over 7 days to glucose (90 mM), the intracellular transport via ouabain and furosemide-blocked channels is decreased, whereas it is increased through the third pathway. Total intracellular accumulation of 86Rb (potassium) ions in mesothelial cells cultured in a medium supplemented with various concentrations of glucose is decreased, and this effect is proportional to the concentration of glucose in the medium.

The intracellular transport of potassium in mesothelial cells is regulated through at least three independent mechanisms. Acute or chronic exposure of mesothelial cells to a hypertonic medium affects the intracellular accumulation of potassium, an d this effect is specific for the various osmotic solutes.

To chemically identify and quantify glucose degradation products in heat sterilized fluids for peritoneal dialysis.

Three different brands of commercial PD-fluids and one laboratory made fluid, sterilized either by heat or filtration, were investigated for the presence of aldehydes.

Aldehydes were identified and quantified using high performance liquid chromatography and gas chromatography.

The tested brands of heat sterilized PD-fluids were found to contain several different aldehydes while the sterile filtered PD-fluid contained none. The highest concentrations in commercial PD-fluids of these aldehydes were: acetaldehyde (420 μm), glyoxal (14 μm), methylglyoxal (12 μm) and formaldehyde (11 μm). Valeraldehyde was also identified but not quantified. The presence of 5–HMF (15 μm) and 2-furaldehyde (2 μm), which has been identified by others, was confirmed.

The heat sterilization of commercial PD fluids gives rise to several aldehydes which may contribute to adverse effects of PD-fluids on patients.

During continuous ambulatory peritoneal dialysis (CAPD), the loss of complement factors via the dialysate may cause complement deficiencies. This hypothesis was tested in a group of children treated with CAPD.

Classical (CH50) and alternative (AP50) complement activity and serum levels of factors C1 q, C3, C4, C3d, B, D, and P in CAPD patients were compared to normal controls and to children with preterminal renal failure.

Patients were seen in a university hospital; normal controls were seen in an outpatient clinic of a general hospital.

A group of 22 children on CAPD was compared to a normal control group of 44 children and to a group of 12 children with preterminal renal failure with a creatinine clearance below 25 mL/min/1.73 m2.

CH50, AP50, C3, and B were not significantly different from the control group in both the CAPD and preterminal groups. Factors C1q (p=0.01) and C4, C3d, D, and P (p<0.001) were higher in the CAPD group in comparison to the normal control group. The factors D (p<0.001) and P (p=0.02) were also elevated in the preterminal group. For the measured factors there was no significant difference between the CAPD group and the preterminal group.

There is no deficiency of complement in children treated with CAPD. High levels of C3d and D can be explained by the reduction of their elimination by the kidney. The increased levels of the other factors are presumably due to increased synthesis in renal failure. This does not seem to be caused by CAPD.

To examine the effect of a reduced calcium/magnesium dialysis fluid (1.25/0.25 mmol/L, respectively) on calcium and magnesium mass transfer in both 1.36% and 3.86% glucose solutions.

Each patient underwent four test exchanges, two with a standard dialysis fluid containing 1.36% and 3.86% glucose, and two with a reduced calcium/magnesium fluid containing 1.36% and 3.86% glucose. Calcium and magnesium were measured in dialysate and serum at ° and 240 minutes.

Single renal unit of a university teaching hospital.

Sixteen patients established on CAPD, and peritonitis-free, for at least 3 months.

A lower dialysate calcium results in negative mass transfer when serum-ionized calcium exceeds dialysate calcium (mean -.0.21±0.15 mmol/exchange), and positive mass transfer when serum-ionized calcium is less than dialysate calcium in 1.36% glucose solutions (mean 0.57±0.18 mmol/exchange). A negative correlation was found between serum-ionized calcium level and calcium mass transfer. With a 3.86% reduced calcium/magnesium solution, calcium mass transfer is always negative (-.0.88±0.18 mmol/exchange) due to ultrafiltration and solute drag.

Fifteen patients were found to be hypermagnesemic at the time of the study. Magnesium mass transfer was neutral with the standard 1.36% glucose fluid (mean -.0.01 mmol/exchange), but negative with the reduced calcium/magnesium 1.36% glucose fluid (mean -.0.58±0.13 mmol/exchange). With the 3.86% glucose solution, both fluids produced negative magnesium mass transfer (mean -.0.32±0.11 and -1.07±0.11 mmol/exchange for standard and reduced calcium/magnesium fluids, respectively).

We conclude that this fluid formulation should reduce hypercalcemia and hypermagnesemia in CAPD patients.

To determine the natural history of a surgically placed Tenckhoff catheter in patients on continuous ambulatory peritoneal dialysis (CAPD).

Prospective 7–year study analyzing catheter survival of all catheters using the Kaplan-Meier life table methodology.

Teaching hospital, department of nephrology.

One hundred and fifteen unselected patients beginning CAPD.

Removal of the catheter required for the following complications: exit-site or tunnel infections or relapsing peritonitis, outflow obstruction, pericatheter leak, and development of hernias.

Period between insertion and removal of the catheter.

The cumulative survival of all catheters after 1,2, and 3 years of CAPD was 87%, 69% and 65%. Catheter survival of the first versus the second catheter after 1 year was significantly longer (p=0.03). The difference was not significant in relation to diabetes, age, and sex. Infectious complications caused 61% (n=19) of all 31 catheter failures, mainly due to tunnel infections caused by Staphylococcus aureus (n=12). “Mechanical” complications accounted for 49% (n=12) of catheter failures. Eight of 12 mechanical complications were outflow failures. Seven patients had to be transferred to hemodialysis.

The straight Tenckhoff catheter is a reliable peritoneal access device for CAPD in an unselected patient population.