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

To determine the ability of the dialysis adequacy and transport test (DATT) to monitor changes in peritoneal transport characteristics over time.

University-based peritoneal dialysis program.

One hundred patients on continuous ambulatory peritoneal dialysis who underwent 226 simultaneous DATTs and peritoneal equilibration tests (PET).

Retrospective analysis of DA TT and PET data.

The mean 24-hour dialysate-to-plasma creatinine (cr) concentration ratio (DIP cr) from the DATT was 0.70±0.10, and the mean four-hour DIP crfrorn the PET was 0.68 ± 0.10. The correlation coefficient between the fourhour and 24-hour DIP cr was 0.81, and the standard error of estimate was 0.065. The mean (±SD) difference between the four-hour and 24-hour DIP cr was 0.023 ± 0.061. Fifty eight patients had two or more sequential DA TTs and PETs. For these 94sets of sequential DATTs and PETs, the mean (±SD) difference between the change in the four-hour DIP cr and the change in the 24-hour DIP cr was 0.020 ± 0.024, and the standard error of estimate was 0.064. In 17 patients a change in dwell volume from 2.0 L to 2.5 L occurred between the first and second measures of peritoneal membrane transport characteristics. The mean (±SD) difference between the change in the four-hour DIP cr and the change in the 24-hour DIP cr was 0.036 ± 0.055, and the standard error of estimate was 0.087.

The DATT can be used to monitor for changes in peritoneal transport over time. It should not be used in patients receiving cycler therapy or in patients whose dwell times and dextrose concentrations vary markedly from day to day.

The purpose of the present study was to compare the dosage requirements of recombinant human erythropoietin (rHuEPO) administered subcutaneously (SC) either one or three times weekly.

A randomized, prospective study. .Setting: The patients were recruited from two university hospitals and five county hospitals.

Thirty-three anemic patients on continuous ambulatory peritoneal dialysis (CAPD) treatment for endstage renal failure completed the study.

Initially, all were treated with rHuEPOSC three times a week until hemoglobin blood levels (Hb) remained constant between 105 and 121 g/L for three months. Following randomization, 17 patients continued the same treatment schedule (group A), while 16 patients received the same dose, but administered only once weekly for three months (group B).

The Hb levels and rHuEPO doses at the start and at the end of the three-month study period.

In group A the median Hb at randomization was 118 g/L (109 -119) (25 -75 percentiles) and, after three months, was 113 g/L (106 -119) (p = 0.13), while in group B the median Hb was 114g/L (108–119) and 114 g/L (106 -120), respectively (p = 0.50). In group A the weekly dose of rHuEPO remained virtually unchanged during the study period, 65 (55 -86) and 66.3 (55 -95) U/kg/week, respectively, while in group B it was increased from 60.2 (46–88) to 77 (60 90) U/kg/week. The 22% increase (p = 0.03) took place during the last two weeks.

Our findings indicate that a once-weekly SC dosing regimen of rHuEPO in anemic CAPD patients was equally effective in maintaining a stable hemoglobin level as a thrice-weekly dosing regimen.

To improve the growth characteristics of human peritoneal mesothelial cells (HPMC).

The effect of commonly used agents, L-cysteine and epidermal growth factor (EGF), added individually (“single”) or mixed with hydrocortisone and apo-transferrin (“admixture”) in the culture medium (M199) on cultured HPMC, was investigated. Methods: Growth agents were added to M199 medium along with 2% fetal bovine serum and L-glutamine. Growth was determined by the analysis of thymidine ([methyl-3H] thymidine) incorporation into deoxyribonucleic acid, total cell protein, and by cell counts. Morphology was assessed by phase contrast light microscopy and scanning electron microscopy.

HPMC exposed to L-cysteine 0.25 x 10–3 mol/L (30 μg/mL) exhibited significantly improved attachment and growth. Attached cells appeared flat and well spread out shortly after seeding, and produced a tight polygonal monolayer in 14 days, in contrast to the growth of HPMC in control M199 medium, which failed to reach confluence. After an initial lag period in cell growth, EGF (0.01 μg/mL) produced a greater increase in cell growth than L-cysteine did; however, this was associated with changes in HPMC morphology. During the growth period (14 days), EGF-stimulated HPMC appeared distorted and irregular compared to L-cysteine-treated cells, which had the characteristic tight “cobblestone” appearance.

L-cysteine improved cell attachment with preservation of the characteristic morphology of HPMC. Epidermal growth factor improved cell growth but produced changes in morphology. The addition of L-cysteine to the culture medium has an important cell growth enhancement role due to the improved cell attachment and cell viability.

To analyze interleukin (IL)-10, interferon gamma (IFN-y), IL-2, and soluble IL-2 receptor alpha (sIL2Rα) in the dialysate and serum of patients on continuous ambulatory peritoneal dialysis (CAPD).

Samples from dialysate bags were collected during the initial month of dialysis. During peritonitis, samples were collected from the first three bags on the day of admittance to the hospital and from the night bags on days 3 and 10. Serum samples were drawn on days 1 and 10. .Results: IL-10 was detected in all dialysate samples except one on the first day of infection, with a peak median level of 50 pg/mL and a slow decrease thereafter. In serum the median levels never exceeded detectable levels. Patients infected with Escherichia coli or Staphylococcus aureus had higher IL-10 levels in dialysate on day 3 as compared to the remaining patients (p < 0.05). If the catheter had to be drawn, because of persistent cloudy dialysate, the IL-10 levels remained elevated for a longer time (p<0.05). IFN-y and IL-2were detected only in the dialysate of patients infected with either S. aureusor S. epidermidis. Only one serum sample showed increased IFN-y. SIL-2Rα was found in all the serum and dialysis samples from the first day of infection. Contrary to the analyzed cytokines, the receptor showed several fold higher levels in serum as compared to the dialysate. During the infection the receptor levels in the dialysate increased, while they remained stationary in the serum, indicating a local production.

This is the first time IL-10 has been demonstrated in the dialysate during peritonitis in CAPD patients. In view of its role as a suppressor of the immune and inflammatory responses, it is a potentially important observation, which might have clinical implications in the future.

The purpose of this work was to develop an animal model of sclerosing encapsulating peritonitis, a complication of continuous ambulatory peritoneal dialysis in which the intestines are conglomerated into an ovoid cocoonlike structure.

Toward this end, rats were injected with a chemical irritant (household bleach) intraperitoneally. One week later, before the resultant peritonitis could cause adhesions, 10 or 25 mL of fresh whole rat blood was injected into the peritoneal cavity. Two weeks later, the effect of the treatments was evaluated by macroscopic and microscopic study.

The irritant caused a chemical peritonitis. The subsequently injected blood clotted on the surfaces of the inflamed intestines, and contraction of the clot (syneresis) was responsible for bringing the intestinal loops together. This conglomeration was made permanent by the fibrosis evoked by the chemical peritonitis. The end result was an ovoid encapsulated mass of intestines and other viscera.

An animal model for an abdominal cocoon has been produced. It can be used for studies of the pathogenesis and prevention of this complication of peritoneal dialysis.

To estimate the maximal body surface area (BSA) at which an uric chronic peritoneal dialysis patients can achieve adequate peritoneal dialysis using a variety of continuous ambulatory peritoneal dialysis (CAPD) and cycler regimens. Adequate dialysis was defined as a creatinine clearance of either 60 L/week/1.73 m2 or 70 L/ week/1.73 m2.

Calculation of daily peritoneal creatinine clearances using standard formulas. For CAPD patients, creatinine clearance was calculated using published values for dialysate-to-plasma ratios for creatinine (DIP cr) measured over a 24-hour period and assuming a daily ultrafiltration rate of 1.5 to 2.0 L/day. For cycler patients, creatinine clearance was calculated for both one and two-hour dwell volumes, using published values for DIP cr from the peritoneal equilibration test and assuming a daily ultrafiltration rate of 2.0 L/day. All clearances were corrected to a normalized body surface area of 1.73 m2.

For CAPD patients, 2– L dwell volumes can provide a weekly creatinine clearance of 60 L/week/1.73 m2 in patients with BSA < 1.45 m2 in the high transporter group and with BSA < 1.2 m2 in the low-average transporter group. Increasing dwell volume from 2.0 to 2.5 L increases these BSA limits in the four transport groups by 0.2 0.3 m2. Cycler therapy is not a viable option for patients in the low transporter group, and this therapy can achieve adequate creatinine clearances in patients in the low-average transport group only with large dwell volumes and in patients with BSA < 1.55 m2. However, in the high-average and high transporter groups, cycler therapy provides for superior creatinine clearances compared to CAPD patients using similar dwell volumes.

Adequate creatinine clearances in anuric patients are most likely to be achieved in patients with BSA > 2.0 m2 if they have high-average or high transport characteristics and are receiving cycler therapy with large dwell volumes and at least one daytime dwell. However, adequate creatinine clearances may be difficult to achieve in an uric patients who have a large BSA an d a low or low-average transport type, regardless of peritoneal dialysis modality. These patients should be considered for either high-dose peritoneal dialysis (multiple daytime and nighttime exchanges) or hemodialysis therapy.

Peritoneal catheters often become dislocated, and this may lead to malfunction. Since it is not usually possible to bring them back into their correct position, they must be replaced. With the aim of preventing this complication, we designed a new catheter.

The new catheter has the same form as the Tenckhoff catheter except for a small increase in external diameter of the last 2 cm, made possible by the high specific weight of a small12-g tungsten cylinder incorporated in the Silasticat the abdominal end. The new catheter may be inserted by a percutaneous technique.

University hospitals of Sienaand Perugia, Italy.

In the last three years, 32 of these catheters have been implanted for a total experience of 468 patientmonths. Their position was checked on insertion and every two months thereafter by radiography; 26 Tenckhoff catheters (415 patient-months) were studied at the same time. Insertion was performed surgically and by a percutaneous method. The frequency of cuff extrusion, exit-site infections, leakage, and peritoneal infection were noted, together with peritoneal function, which was evaluated by KTN and weekly creatinine clearance one month after catheter insertion; the tests were repeated when dislocation occurred and at the end of the trial.

No dislocations occurred with the self-locating catheters, whereas nine dislocations occurred in control patients (p = 0.0003). There were no significant differences with respect to controls for cuff extrusion, exit-site infections, leakage, peritoneal infection, and peritoneal function.

The presence of a small weight at the catheter tip prevents displacement completely, keeping the intraperitoneal part of the catheter in place.

To discuss potential reasons for reported differences in the results of several recent studies comparing mortality risk among continuous ambulatory peritoneal dialysis (CAPD) and hemodialysis patients, and to assess the role of statistical methods and study design.

Recent published reports comparing mortality risk among patients treated with CAPD and hemodialysis.

Differences in study design, study populations, sample size, data collection, and availability of data likely account in part for the differences in available study results. The Cox model is a valuable tool, particularly for observational studies. Observed outcome differences for CAPD and hemodialysis patients may be due to either the dialytic modality itself or other factors such as differences in patient selection, practice patterns, dialysis dose, patient compliance, etc. Relative mortality rates for hemodialysis and CAPD patients may vary by country, as these factors may differ internationally. A randomized clinical trial is necessary to best determine the effect of the modality itself.