Peritoneal dialysis survival in relation to patient body size and peritoneal transport characteristics.

This study compares patient and technique survival on continuous ambulatory peritoneal dialysis (CAPD) and other peritoneal dialysis (PD) modalities in relation to body size indicators, race, sex, and peritoneal transport characteristics. Data were abstracted from a PD adequacy database, with 354 patients subjected to analysis. Transfers between PD modalities were almost exclusively from CAPD to various offshoots of PD, mostly due to inadequate dialysis or inadequate ultrafiltration. Survival analysis showed better technique survival for other PD modalities compared to CAPD when body mass index was less than 25 kg/m2, body surface area (BSA) was less than 1.9 m2, total body water was less than 39 L, and the dialysate-to-plasma ratio of creatinine at four hours was less than 0.65 by the peritoneal equilibration test (PET). There were no differences found in relation to gender, race, or PET ratio of dialysate glucose at four hours to dialysate glucose at time zero. In other PD modalities, no differences in technique and patient survival were found in regard to the same parameters, with the exception of better technique survival in males with a BSA over 1.9 m2. In conclusion, CAPD technique survival is better in the small patient with below average peritoneal transport characteristics. In other PD modalities, survival is not related to anthropometric indices or peritoneal transport characteristics.

Long-term follow-up of body size indices, residual renal function, and peritoneal transport characteristics in continuous ambulatory peritoneal dialysis.

Technique survival in continuous ambulatory peritoneal dialysis (CAPD) depends mostly on clearances in relation to body size and residual renal function (RRF). Our clinical impression has been that when RRF fails, larger patients leave CAPD sooner than smaller patients do. Peritoneal equilibration tests (PETs) and 24-hour adequacy evaluations performed in 277 patients in a single center from 1986 through 2009 were abstracted from the existing peritoneal dialysis adequacy database. A PET (using 2 L of 2.5% dextrose dialysis solution) was performed in 272 patients during the first 4 months of dialysis. Every 3 months, the patients brought their 24-hour urine and dialysate collections for adequacy evaluations and had height and weight recorded. Body surface area (BSA), body mass index (BMI), and total body water (TBW) were calculated. There were 1372 adequacy evaluations abstracted. The number of patients gradually declined over time because of death (28%) or transfer to other peritoneal regimens (25%) or to hemodialysis (23%). A small number of patients received a kidney graft (6%) or left CAPD for other reasons (12%); only 6% of patients remained on CAPD after 80 months of treatment. The mean (+/- standard deviation) PET 4-hour values were 0.652 +/- 0.128 for dialysate-to-plasma (D/P) ratio of creatinine (Cr), 0.403 +/- 0.0969 for 4-hour dialysate-to-initial dialysate (D/D0) glucose concentration ratio, and 2336 +/- 211 mL for the drain volume. There was no correlation between PET D/P Cr and BSA (r = 0.0051, p = 0.934), PET D/D0 glucose and BSA (r = 0.0042, p = 0.945), or PET drain volume and TBW. The correlations with other size indicators were very poor. None of the large patients (BSA > 1.9 m2, weight > 75 kg, BMI > 25 kg/m2) remained on CAPD for more than 80 months once they lost RRF. These results confirm our impression that, with declining RRF, larger patients do not continue CAPD as long as smaller patients do.

A study of the extracorporeal rate of blood flow and blood pressure during hemodialysis.

Hemodynamic instability is a common problem during hemodialysis (HD). The effect of blood flow rate (BFR) on blood pressure (BP) during HD has not been previously evaluated. Subjects receiving HD for the treatment of renal failure were enrolled (n=34). For each patient, during the last hour of 2 consecutive HD sessions the BFR was set at 200 mL/min for 30 min and at 400 mL/min for 30 min, during which period the fluid removal rate was kept constant. The order of the BFR alterations was randomized. The study procedure was repeated during the next HD session but with reversal of the order of the altered BFR. During each 30-min period, BP was recorded at baseline and subsequently every 10 min. During the BFR of 400 mL/min, subjects had a higher systolic BP by an average of 4.1 mmHg compared with the BFR of 200 mL/min (95% confidence interval [CI] 0.22-7.98; p=0.038). Similarly, during the BFR of 400 mL/min, subjects had a higher diastolic BP by an average of 3.04 mmHg compared with the BFR of 200 mL/min (95% CI 0.55-5.53; p=0.017). Likewise, during the BFR of 400 mL/min, subjects had a higher mean arterial pressure by an average of 3.44 mmHg (95% CI 0.77-6.11; p=0.012). The findings suggest that during HD, BPs are maintained higher at higher BFRs as compared with lower BFRs.

A 9-year survival analysis of the presternal Missouri swan-neck catheter.

Peritoneal dialysis (PD) catheter survival is challenging because of infection and malfunction. The swan-neck presternal catheter has a coiled intra-abdominal segment with a bead and a flanged cuff at the peritoneum; a titanium adapter joins the abdominal segment to the upper segment. The upper segment has two cuffs, one on either side of the presternal swan-neck segment. The present study evaluated the survival of Missouri presternal swan-neck PD catheters implanted at the University of Missouri--Columbia and followed at Dialysis Clinics, Inc., through 2006. Catheter type and insertion date were prospectively recorded. Survival was defined as the interval from insertion date to date of removal, censoring, or analysis. Catheters were censored for transplant, death, or transfer to another unit. A total of 131 presternal catheters were implanted in 129 patients. Mean patient age was 60.9 +/- 16.3 years. No catheters were removed during the first 3 months for either infection or technical problems. One catheter was removed at 6 months for malposition and another at 2 years for an external leak; all other catheter losses were attributable to peritonitis. Cumulative catheter survival was 93.5%, 82.5%, 63.9%, and 60.0% at 1, 2, 3, and 4 years respectively. The mean observation period was 19. 7 +/- 17.8 months, and the longest catheter survival was 87.5 months. New episodes of peritonitis were 91 in number, a rate of 1 episode per 28 patient-months. Although catheter survival exceeded the recommendation of better than 80% at 1 year, we noted a trend toward lower catheter survival and a higher peritonitis rate than were reported earlier in this series with a smaller number of catheters. That trend is partly explained by repeated episodes of peritonitis in 11 catheters; 8.5% of the patients experienced 40% of the peritonitis episodes.

Perceived value of nursing certification--summary of a national survey.

The American Board of Nursing Specialties (ABNS) conducted a survey to determine the value professional nurses place on nursing certification as well as barriers to certification. This article presents an overview of the survey results in general and specifically the views of nephrology nurse participants.

Predictors of hospitalization in patients on peritoneal dialysis: the Missouri experience.

BACKGROUND: We analyzed a large number of demographic and biochemical variables to identify predictors of hospitalization in subjects on peritoneal dialysis (PD). METHODS: All patients initiated on PD at our center from January 1990 through December 1999 were included. The following variables at the initiation of PD were included: demographics, clinical data, nutritional and adequacy parameters, transport characteristics, and various co-morbidities. Co-morbidities were graded for severity using a modified version of the Index of Coexistent Disease. Variables included during the course of PD consisted of weighted time average of a number of laboratory, adequacy, and nutritional parameters along with the number of peritonitis episodes per year. Stepwise linear regression was used following a univariate screening procedure to identify independent predictors of the outcome of hospitalization days per month on PD. RESULTS: The subject population consisted of 191 subjects (105 men, 86 women; 180 Caucasians, 10 African-American, 1 Asian). The mean age was 61 +/- 13 (SD) years and mean duration of follow-up was 21 +/- 18 months. The baseline variable analysis revealed that the presence of partner to perform PD predicted increased hospitalization (p < 0.0001). Additionally, the presence and severity of peripheral vascular disease and residual renal Kt/V at baseline (negative association) predicted increased hospitalization. In the analyses of ongoing variables, stepwise linear regression solely identified weighted time average albumin as a strong negative predictor of hospitalization (p < 0.0001). CONCLUSION: A comprehensive analysis of a large number of variables revealed that serum albumin during the course of PD (negative association) and the need for partner to perform PD strongly predicted increased hospitalization in PD subjects.

Current trends in the use of peritoneal dialysis catheters.

The Tenckhoff catheter was developed in 1968 and has been widely used since for chronic peritoneal dialysis (PD) patients. Variations of the Tenckhoff catheter have been designed over the years in a search for the ideal PD catheter--an access that can provide reliable dialysate flow rates with few complications. Currently, data derived from randomized, controlled, multicenter trials dedicated to testing how catheter design and placement technique influence long-term catheter survival and function are scarce. As a result, no firm guidelines exist at the national or international levels on optimal PD catheter type or implantation technique. Also, no current statistics on the use of PD catheters are available. The last survey was carried out using an audience response system at the Annual Peritoneal Dialysis Conference in Orlando, Florida, in January 1994. The present analysis is based on a new survey done at the 2005 Annual Dialysis Conference in Tampa, Florida. It is a snapshot of preferences in catheter design and implantation technique in 2004 from an international sample of 65 respondent chronic PD centers. The Tenckhoff catheter remains the most widely used catheter, followed closely by the swan-neck catheter in both adult and pediatric respondent centers. Double-cuff catheters continue to be preferred over single-cuff catheters, and coiled intraperitoneal segments are generally preferred over straight intra-peritoneal segments. Surgical implantation technique remains the prevailing placement method in both pediatric and adult respondent centers.

Predictors of death in patients on peritoneal dialysis: the Missouri Peritoneal Dialysis Study.

BACKGROUND: The study was designed to identify predictors of death in subjects on peritoneal dialysis (PD). METHODS: The population consisted of patients initiated on PD at the University of Missouri-Columbia and Dialysis Clinic Incorporated from January 1, 1990, through December 31, 1999. Baseline variables included demographics, clinical data, initial measures of nutritional status, adequacy, and transport characteristics. Co-morbidities were scored using a modified version of the Index of Coexistent Disease. Ongoing (during the course of PD) variables consisted of clinical characteristics and weighted time average of a number of laboratory, adequacy, and nutritional variables. The variables were screened using a univariate procedure, and then analyzed using stepwise logistic regression to evaluate their independent relation to death. RESULTS: There were 105 men and 86 women--180 Caucasians, 10 African-American, 1 Asian, mean age 61 +/- 13 (SD) years, and mean duration of follow-up 21 +/- 18 months. Eighty-two patients suffered the outcome of death. Lean body mass (LBM) at the initiation of PD was negatively associated with the risk of death (p < 0.01). In addition, the need for a partner to perform PD, total morbidity count, and the summated severity score of all co-morbidities were associated with an increased risk of death. The analysis of ongoing variables revealed that serum phosphate (negative association, p = 0.02) and number of hospitalization days per month on PD (p = 0.0006) were associated with an increased risk of death. CONCLUSION: Phosphate levels and LBM are strong negative predictors of death in PD subjects. Further, patients who need the assistance of a partner to perform PD have decreased survival.

Rates of continuous ambulatory peritoneal dialysis-associated peritonitis at the University of Missouri.

Peritoneal dialysis (PD)-associated peritonitis contributes significantly to morbidity and modalityfailure. The number of patients on PD is declining in Western countries, and peritonitis is a potential deterrent to the therapy. Here, we present a clinically significant decline in the rate of peritonitis at a single center over a 28-year period, with current rates significantly lower than the national average, and we review several factors that have contributed to those outcomes. Peritonitis and duration of follow-up have been recorded for all patients followed in our program since 1977. Introduction of important technological changes into the program were also recorded. All peritonitis rates are expressed as episodes/patient-year or episodes/n patient-months. Data are summarized for each calendar year since 1977. We followed 682 patients for a total follow-up duration of 15,435 patient-months. Glass bottles were changed to plastic bags in 1978. Straight connecting tubes were replaced by Y-sets in 1988. The presternal dialysis catheter was introduced in 1991 and has been the primary PD access since 1995. The peritonitis rate in 1977 was 5.8 episodes/patient-year, and that rate has progressively declined over the past 27 years to 0.35 episodes/patient-year in 2004. Technical improvements that contributed to the decline in overall peritonitis rates have been adopted nationwide. The largest improvement occurred with the switch from glass bottles to plastic bags, and to the closed-system Y-set that incorporated the flush-before-fill principle. Advances in catheter technology have also played a key role. Quality improvement in the program and long years of experience in overall care of PD patients are significant factors that cannot be measured quantitatively. Improvements have been made to exit-site care protocols, to exit-site evaluation and diagnosis, and to treatment strategies. Patient education and training in catheter care remain the important factor in a PD program. Many factors have contributed to the reduction of PD-associated peritonitis rates at our center Improved connectology, catheter care, and patient education play key roles in the reduction of peritonitis.

Use of tissue plasminogen activator in peritoneal dialysis catheters: a literature review and one center's experience.

There have been anecdotal reports of the use of tPA for obstructed peritoneal dialysis catheters in both adults and children. This manuscript reviews the literature and summarizes common elements of the procedures used for tPA administration in peritoneal dialysis catheters. The Gambro New Haven experience with administration of tPA (8 mgs in 10 ml of sterile water injected into the catheter and allowed to dwell for 1 hour) in 29 cases of catheter obstruction in 18 patients is presented. Patency was restored in 24 instances with no adverse effects. In the 5 cases that did not respond, the primary cause of poor drain was catheter malposition in 2, constipation in 2, and adhesions in 1. tPA was also administered to 5 patients with relapsing peritonitis; 3 patients, all with Staphylococcus epidermidis, recovered and did not experience further recurrence.

Response to inadequate dialysis in chronic peritoneal dialysis patients. Results from the 2000 Centers for Medicare and Medicaid (CMS) ESRD Peritoneal Dialysis Clinical Performance Measures (PD-CPM) Project.

BACKGROUND: It is not known if patient prescriptions are being changed if patients are receiving an inadequate dose of peritoneal dialysis. METHODS: Data from the 2000 Centers for Medicare and Medicaid were used to obtain data on dialysis adequacy and dialysis prescriptions. RESULTS: A total of 359 of 1,268 (28%) adult peritoneal dialysis patients had a total weekly Kt/V urea (twKt/V) less than 2.0 and 436 of 1,245 (35%) patients had a total weekly creatinine clearance (twCrCl) less than 60 L/wk/1.73 m2, defined as "inadequate dialysis." Among chronic ambulatory peritoneal dialysis (CAPD) patients, 81 of 188 (43%) patients had inadequate dialysis and a change in the peritoneal dialysis prescription within 6 months of the initial adequacy value. Among cycler patients, 106 of 197 (54%) patients had inadequate dialysis and a change in the prescription. Thirty-six of 46 (78%) CAPD patients and 48 of 56 (86%) cycler patients had an improvement in twKt/V after the prescription was revised. Thirty-two of 42 (76%) CAPD patients and 45 of 57 (79%) cycler patients had an improvement in twCrCl after the prescription was changed. For these patients, twKt/V increased from 1.6 +/- 0.3 to 2.1 +/- 0.5, with an increase in the peritoneal Kt/V urea from 1.5 +/- 0.3 to 1.9 +/- 0.4. Similarly, twCrCl increased from 46.3 +/- 7.5 to 59.1 +/- 10.6 L/wk/1.73 m2 with an increase in the peritoneal CrCl dose from 42.0 +/- 9.1 to 52.7 +/- 9.9 L/wk/1.73 m2. CONCLUSION: About half of peritoneal dialysis patients with inadequate dialysis did not have a prescription change and could benefit from modifications in their dialysis prescription.

Retrospective evaluation of renal kt/V(urea) at the initiation of long-term peritoneal dialysis at the University of Missouri: relationships to longitudinal nutritional status on peritoneal dialysis.

The purpose of this study was to examine the impact of low levels of residual renal function (RRF) on nutritional status in end-stage renal disease patients starting peritoneal dialysis (PD) at baseline and after a year on dialysis. We conducted a single center retrospective analysis of 116 patients who started long-term PD in a university teaching hospital from 1989 to 1998 and were followed for 1 year. Patients were divided into four equal groups according to their initial renal Kt/V(urea) (L/week) levels at the start of PD and followed for 1 year. There were no interventions. The relationship between dialysis adequacy (renal and total Kt/V(urea)) and nutritional status was studied at baseline and at 1 year. Baseline data for patients who survived were compared with the baseline data of those who died and with their own 1 year data. At baseline, the mean serum albumin (3.31 g/dl, p < 0.0001) and lean body mass (47.20% body weight, p < 0.04) of group 1 were significantly lower than in groups 2, 3, and 4. Levels of normalized protein equivalent of nitrogen appearance (nPNA) were significantly lower in group 1 than in groups 3 and 4 (p < 0.005). Although group 1 patients showed trends toward improvement in nutritional parameters, they never caught up with the other groups. At the end of 1 year, the lower total Kt/V(urea) in group 1, with the lowest RRF, was associated with the lowest mean values for nutritional status and the highest death rate. Comparison of baseline and 1 year data of survivors showed that nutritional status improved or remained stable in groups 3 and 4, who exceeded the minimum recommended adequacy targets as per Dialysis Outcome Quality Initiative criteria (mean 12 month total Kt/V(urea) 2.18 and 2.58, respectively). Comparison of baseline data of survivors and those who died showed that patients who died had lower mean values for serum albumin, nPNA, lean body mass, and body weight across all groups. Low RRF at the start of dialysis is associated with poor nutritional status. Also, patients who start dialysis with low RRF and poor nutritional status do not have significantly improved nutritional status even after 1 year on dialysis.

Air-bubble method of locking central-vein catheters for prevention of hub colonization: a pilot study.

BACKGROUND: The major source of catheter-associated bacteremia is contamination of the catheter hub during connection-disconnection procedures. A new method of catheter locking has been developed wherein anticoagulant is injected first, followed by a 0.1-mL air bubble and 0.9 mL of bactericidal solution. The anticoagulant is then located at the catheter tip and the bactericidal solution is located at the catheter hub. The air bubble prevents mixing of the two solutions. The bactericidal solution was acidified concentrated saline (ACS). The 27% saline solution has a pH of 2.0. ACS was chosen because it is theoretically harmless if injected in the amount used to lock the catheter lumens. The goals of this pilot study were to determine whether the new method of catheter locking is easy to perform with available syringes and whether eventual injection of the experimental solution is well tolerated. METHODS: Ten patients were randomly assigned, either to heparin lock (5 patients, 62 treatments) or air-bubble method (5 patients, 56 treatments). In the control group, the catheters were locked with heparin, 5000 U/mL. In the experimental group, the catheters were locked with heparin, air bubble, and ACS. Altogether, the lumens were overfilled by 0.2 mL. RESULTS: Compared to the routine method, the experimental method required a 1- to 2-min-longer procedure time. There were no errors in proper sequence of injections into the lumina. There were no episodes of bacteremia related to hub contamination in either group. In the air-bubble group, there was one case of bacteremia associated with purulent drainage from the exit and the same organism in both cultures. In three instances in each group, the locking solution could not be aspirated and was injected without any subjective symptoms or objective signs. CONCLUSION: We conclude that the air-bubble method of locking central-vein catheters is easy to perform. In three instances of air-bubble and ACS injection, there were no adverse effects. A full-scale prospective randomized study is feasible and warranted.