Dialysate leakage represents a major noninfectious complication of peritoneal dialysis (PD). An exit-site leak refers to the appearance of any moisture around the PD catheter identified as dialysate; however, the spectrum of dialysate leaks also includes any dialysate loss from the peritoneal cavity other than via the lumen of the catheter. The incidence of dialysate leakage is somewhat more than 5% in continuous ambulatory peritoneal dialysis (CAPD) patients, but this percentage probably underestimates the number of early leaks. The incidence of hydrothorax or pleural leak as a complication of PD remains unclear. Factors identified as potentially related to dialysate leakage are those related to the technique of PD catheter insertion, the way PD is initiated, and weakness of the abdominal wall. The pediatric literature tends to favor Tenckhoff catheters over other catheters as being superior with respect to dialysate leakage, but no consensus on catheter choice exists for adults in this regard. An association has been found between early leaks (< or =30 days) and immediate CAPD initiation and perhaps median catheter insertion. Risk factors contributing to abdominal weakness appear to predispose mostly to late leaks; one or more of them can generally be identified in the majority of patients. Early leakage most often manifests as a pericatheter leak. Late leaks may present more subtly with subcutaneous swelling and edema, weight gain, peripheral or genital edema, and apparent ultrafiltration failure. Dyspnea is the first clinical clue to the diagnosis of a pleural leak. Late leaks tend to develop during the first year of CAPD. The most widely used approach to determine the exact site of the leakage is with computed tomography after infusion of 2 L of dialysis fluid containing radiocontrast material. Treatments for dialysate leaks include surgical repair, temporary transfer to hemodialysis, lower dialysate volumes, and PD with a cycler. Recent recommendation propose a standard approach to the treatment of early and late dialysate leaks: 1-2 weeks of rest from CAPD, and surgery if recurrence. Surgical repair has been strongly suggested for leakage causing genital swelling. Delaying CAPD for 14 days after catheter insertion may prevent early leakage. Initiating CAPD with low dialysate volume has also been recommended as a good practice measure. Although peritonitis and exit-site infections are the most frequent causes of technical failure in peritoneal dialysis (PD), dialysate leaks represent one of the major noninfectious complications of PD. In some instances, dialysate leakage may lead to discontinuation of the technique (1). Despite its importance, the incidence, risk factors, management, and outcome of dialysate leakage are poorly characterized in the literature. We will review the limited available information on this topic in the next few sections.

Catheters, Indwelling↗

PubMedDate not supplied

On-line dialysis quantification in acutely ill patients: preliminary clinical experience with a multipurpose urea sensor monitoring device.

Direct dialysis quantification offers several advantages compared with conventional blood urea kinetic modeling, and monitoring urea concentration in the effluent dialysate with an on-line urea sensor is a practical approach. Such a monitoring device seems desirable in the short-term dialysis setting to optimize and personalize both renal replacement therapy and nutritional support of acutely ill patients. We designed a urea monitoring device consisting of a urea sensor, a multichannel hydraulic circuit, and a PC microcomputer. The sensor determines urea from catalysis of its hydrolysis by urease in liquid solution during neutral conditions. Hydrolysis of urea produces NH4+, and creates an electrical potential difference between two electrodes. Each concentration determination of urea is the average value of 10 measurements; samples are diverted and measured every 7 min. Laboratory calibration of the urea sensor has demonstrated linearity over the range 2-35 mmol/L. Urea monitoring was performed throughout the treatment course, either on the effluent dialysate or ultrafiltrate in seven acutely ill patients treated by either hemofiltration (n=5) or hemodiafiltration (n=2). The slope of the concentration of urea in the effluent over time was used to calculate an index of the dialysis dose delivered (Kt/V), urea mass removal, and protein catabolic rate. In addition, samples of the effluent were drawn every 21 min, and sent to the central laboratory for measurement of urea concentrations using an autoanalyzer. Kt/V values also were calculated with Garred's equation using pre and post session concentrations of urea in blood. Concentrations of urea in the effluent determined by the urea sensor were found to be very close to those obtained from the central laboratory over a wide range of values (3 to 42 mmol/L). In addition, Kt/V values for both hemofiltration and hemodiafiltration, when calculated with concentrations of urea in the effluent obtained by the urea sensor, did not significantly differ from Kt/V values obtained from the laboratory concentrations of urea in the effluent. On-line urea sensor monitoring of the effluent suppresses the cumbersome task of total effluent collection, and the complexity of urea kinetic analysis. The multipurpose prototype described here represents a new, simple, and direct assessment of dialysis dose and protein nutritional status of acutely ill patients, and is suitable for various modalities.

Acute Kidney Injury↗

PubMedDate not supplied

Variation of intra-access flow early and late into hemodialysis.

Intra-access flow (Qac), measured by ultrasound dilution, is a reliable method for screening for access dysfunction. Because of a reduced circulating volume and a relative decrease in blood pressure at the end of hemodialysis (HD), we hypothesized that Qac could be significantly reduced when measured late into HD. Fifty patients were prospectively evaluated for variation in Qac early and late into HD. There were 33 native fistulae and 17 synthetic grafts. Six separate measures of Qac were performed for each patient by ultrasound dilution (Transonic HD01 hemodialysis monitor; Transonic Systems, Inc., Ithaca, NY): three within the first 30 minutes and three within the last 30 minutes of HD. Session time was 3.5 or 4 hours, and mean net ultrafiltration was 3.3 +/- 0.9 L/HD. Early and late into HD, mean arterial pressure (MAP) decreased from 100.0 +/- 14.6 to 92.8 +/- 17.8 mm Hg, heart rate from 73 +/- 11 to 79 +/- 15 bpm, and hematocrit increased from 34 +/- 3 to 38 +/- 4%. For the whole group, mean Qac decreased from 1,101.7 +/- 566.7 to 972.5 +/- 515.6 ml/min (p = NS); when Qac was corrected for a MAP of 100 mm Hg, the reduction remained nonsignificant (from 1,101.7 to 1,048.0 ml/min). When considering native and synthetic fistulae separately, the drop in Qac was still nonsignificant (from 1,098.9 +/- 613.4 to 983.2 +/- 593.2 for native fistulae versus 1,107.2 +/- 480.5 to 999.8 +/- 379.8 ml/min for grafts, p = NS). Overall, the percent reduction in Qac early versus late into HD was 11.7%, whereas it reached only 4.9% when access flows corrected for MAP were considered. We conclude that variation in Qac during HD is relatively small, especially when values are corrected for MAP. Therefore, according to our results, Qac measures by using the ultrasound dilution method made at any time during HD should be reliable for most patients.

Adult↗

PubMedDate not supplied

Renal replacement in end-stage renal disease patients over 75 years old.

BACKGROUND: Over the last decade, the age of dialysis patients has been increasing steadily in several units in Canada. Our main objective was to assess prevalence, co-morbidity and outcome of ESRD patients over 75 years old at the beginning of dialysis treatment in our center. As a group, they were compared to younger dialysis patients treated simultaneously. METHODS: In the last 5 years, all cases beginning dialysis in our institution who were above 75 years of age were reviewed, as well as cases aged between 50 and 60 years who started dialysis during the same period. Between January 1996 and December 2000, among a total of 429 new chronic dialysis patients, 67 ESRD patients over 75 years (15.6%) and 66 patients between 50 and 60 years (15.4%) began dialysis treatment. RESULTS--PRIMARY AND SECONDARY: Diabetes was present in 37% of elderly and in 56% of the younger patients. Younger patients had been referred earlier to our nephrologists than the older ones (42 vs. 27%). Elderly were more frequently treated by hemodialysis than peritoneal dialysis (81 vs. 19%) when compared to their younger counterparts (65 vs. 35%). Long-term catheters for hemodialysis were used more often in elderly patients. No renal transplantation were performed in older patients while 7 younger patients received a renal graft. Survival rates after 1 and 3 years were, respectively, 93 and 74% for patients between 50 and 60 years, whereas it decreased to 80 and 45% for those over 75 years (p = 0.002). More than 50% of patients older than 75 years died within 2 years after starting dialysis; their mean survival was 31 months; patients starting dialysis between 50 and 60 years survived on the average 44 months during the study period. According to the multivariate logistic regression model, risk factors for increased mortality in the older group were: number of hospitalization days during the past 3 months (OR 34.8, 95% CI 8.3-145.7, p < 0.001) and lower weight (OR 16.6, 95% CI 2.0-139.0, p = 0.001). CONCLUSION: We may conclude that, in our hands, life expectancy of patients who began dialysis above 75 years is significantly shorter than for patients for whom dialysis is initiated between age 50 and 60 years, especially if they have a low weight, lose weight and/or require hospitalization.

Age Factors↗

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