Objective To study the presence of 1,2-dicarbonyl compounds in peritoneal dialysis (PD) fluids, their concentration in effluents with increasing dwell time, and their role in the formation of advanced glycation end-products (AGEs). Measurements Dicarbonyl compounds in heat- and filter-sterilized PD fluids were quantified by reverse-phase high performance liquid chromatography (HPLC) after derivatization to dimethoxyquinoxaline derivatives. Kinetics of the in vitro formation of AGEs upon incubation of 1,2-dicarbonyl compounds or PD fluids with albumin, with or without aminoguanidine, were measured by AGE fluorescence (excitation/emission wavelengths of 350 nm/430 nm). Patients AGEs and dicarbonyl compounds were measured in effluents collected from standardized 4-hour dwells from 8 continuous cycling peritoneal dialysis patients. Results In PD fluids, 3-deoxyglucosone (3-DG) has been identified as the major dicarbonyl compound formed during the process of heat sterilization. The process also formed glyoxal (GO) and methylglyoxal (MGO), with the amount of 3-DG being approximately 25 – 60 times higher than GO and MGO. When incubated with albumin, the identified 1,2-dicarbonyl compounds rapidly formed AGEs. The formation of AGEs was more pronounced in conventional heat-sterilized PD fluids compared with filter-sterilized PD fluids, and was completely inhibited by aminoguanidine. In effluents, the concentration of MGO, GO, and 3-DG decreased with increasing dwell time, with a concomitant increase in AGE fluorescence. Conclusions The dicarbonyl compounds 3-DG, MGO, and GO are potent promoters of AGE formation. The presence of these and possibly other dicarbonyl compounds formed during heat sterilization of glucose-based PD fluids is, to a large extent, responsible for the in vitro AGE formation by these fluids, as evidenced by the speed of AGE formation in PD fluids and the complete inhibition by aminoguanidine. Because 3-DG, MGO, and GO are rapidly cleared from PD fluids during dialysis, these compounds may contribute to the in vivo AGE formation in PD patients.

Icodextrin enhances ultrafiltration during the daytime dwell in CCPD patients. As a result of an increased 24-h ultrafiltration volume, DCl/1.73 m2 and DCl/1.73 m2/l improve. DCl/1.73 m2/l/UF does not rise, which suggests that the increase in DCl/1.73 m2 and DCl/1.73 m2/l is caused by convective transport.

Catheter-related infections result in high patient morbidity, the need for temporary haemodialysis, and high costs. These infections are the main cause of limited technique survival in peritoneal dialysis. We introduced a protocol for the simultaneous peritoneoscopic insertion and removal of peritoneal catheters in patients with catheter-related infections. Peritoneal dialysis was continued the day after surgery using low-volume dwells and a dry abdomen during the daytime. The dialysate leukocyte count had to be below 100/mm3 before exchanging catheters, which was performed under antibiotic therapy based on culture sensitivity. The old catheter was removed after the new catheter had been inserted in the opposite abdominal region. CAPD patients were switched to APD for 1 week, which made prolonged hospitalization necessary. Simultaneous catheter insertion and removal was performed 25 times in 22 patients on CCPD and 15 times in 14 patients on CAPD. In CCPD patients, peritoneal dialysis was restarted after 1.0+/-0.1 days in 24 cases. One patient had sufficient residual renal function and discontinued CCPD until day 10. In 10 CAPD patients (11 procedures) APD was started 1.3+/-0.2 days after the procedure with CAPD beginning 7.1+/-0.6 days thereafter. Three CAPD patients preferred haemodialysis and restarted CAPD 10.0+/-2.1 days after surgery. One patient continued CAPD the day after surgery. In addition to minor complications (e.g. position-dependent outflow problems), dialysate leakage occurred in two patients. Two patients developed peritonitis within the first 30 days after surgery, one of which was procedure related. One patient had severe lower gastrointestinal bleeding 2 weeks after the procedure, which was not related to the catheter replacement. Ultimately, in 38 of 40 procedures the patients could successfully continue peritoneal dialysis. We conclude that simultaneous insertion and removal of a peritoneal dialysis catheter without interruption of peritoneal dialysis is a safe procedure in patients with catheter-related infections.

Objective To investigate peritoneal defense during icodextrin use in continuous cyclic peritoneal dialysis (CCPD). Design In an open, prospective, 2-year follow-up study, CCPD patients were randomized to either glucose (Glu) or icodextrin (Ico) for their long daytime dwell. Setting University hospital and teaching hospital. Patients Both established and patients new to CCPD were included. A life expectancy of more than 2 years, a stable clinical condition, and written informed consent were necessary before entry. Patients aged under 18 years, those who had peritonitis in the previous month, and women of childbearing potential, unless taking adequate contraceptive precautions, were excluded. Thirty-eight patients (19 Glu, 19 Ico) started the study. The median follow-up was 16 and 17 months for Glu and Ico respectively (range 0.5 – 25 months and 5 – 25 months, respectively). Outcome Measures Peritoneal defense characteristics and peritoneal dialysis-related infections were recorded every 3 months. Results Total peritoneal white cell count tended to decrease over time in both groups. After 1 year, absolute numbers and percentages of effluent peritoneal macrophages (PMΦs) were significantly higher in Ico than in Glu patients; this difference in the percentage persisted after 2 years. Percentage of mesothelial cells increased over time in Ico patients. The phagocytic capacity of PMΦs decreased over time, resulting in a borderline significant difference for coagulase-negative staphylococci ( p = 0.05) and a significant difference for Escherichia coli ( p < 0.05) phagocytosis in favor of Ico patients. PMΦ oxidative metabolism remained stable over time without a difference between the groups. PMΦ cytokine production and effluent opsonic capacity also remained stable over time. Finally, 16 peritonitis episodes in Glu and 14 in Ico patients occurred. Glucose patients had 37 and Ico patients 32 exit-site infections during the study. Conclusion CCPD patients using Ico did equally as well as Glu-treated patients with respect to clinical infections and most peritoneal defense characteristics. However, in a few peritoneal defense tests, Ico-treated patients did better.

In contrast to glucose, icodextrin preserved the daytime dwell ultrafiltration during peritonitis. Serum icodextrin metabolites increased during icodextrin use, but remained stable during peritonitis. Adverse effects were not observed.