An original non-traumatic maneuver for repositioning migrated peritoneal dialysis catheters.

OBJECTIVE: To describe an original non-traumatic maneuver for repositioning a migrated peritoneal dialysis (PD) catheter. METHODS: First, tissues wrapping the PD catheter are dissociated, then a correct route is selected according to the position of the catheter, and finally the catheter is repositioned manually in 8 steps: pressing, palpating, vibrating, wave vibrating, rotating, back-pushing and vibrating, swaying, and compressing. RESULTS: Of 30 cases of PD catheter migration, repositioning was successful on the first attempt in 9 cases, on the third attempt in 10 cases, on the seventh attempt in 7 cases, and failed in 4 cases. The overall success rate was 86.7%. CONCLUSION: Manual repositioning of a migrated PD catheter is safe, painless, economical, and feasible. Repositioning of the migrated dialysis catheter may be attempted before referral for more invasive interventions.

Evaluating peritoneal fluid transport in continuous peritoneal dialysis patients: a practical approach.

BACKGROUND/AIMS: Evaluating the peritoneal fluid kinetics is of clinical importance in peritoneal dialysis treatment. We have previously developed a simple way to evaluate the peritoneal fluid transport characteristics in continuous ambulatory peritoneal dialysis patients which, however, cannot be applied to those patients on a fixed dialysis schedule. Therefore, in the present study, we tested the possibility to vary the peritoneal dwell time and tried to develop a more patient-friendly ultrafiltration (UF) collection protocol. METHODS: The patients' UF volume was recorded for 10 days. All patients recruited were asked to perform their usual dialysis exchanges with, however, a special UF data collection protocol to improve the accuracy of computer simulation: at least one dwell of 2-4 h, one of 4-7 h, and one of more than 7 h. The fluid transport model was applied to the pooled UF volume for fluid kinetics simulation, and the data from the following day's UF records using the same glucose concentration and dwell time were used to evaluate reliability and accuracy of the simulated UF value. RESULTS: Fifty-two chronic peritoneal dialysis patients were included in the present study. All of the UF data could be used in the computer simulation, and there was a significant negative correlation between fluid absorption rate (K(e); see text) and actual UF volume on the following day using a glucose concentration of 1.5% and a dwell time of 4 h (r = -0.336, p < 0.05). The estimated UF values correlated significantly with the actually measured UF values. The variability of the results, expressed by the width between the 95% limits of agreement, fell within -139.2 to 131.9 ml, while the mean difference was -3.7 ml. CONCLUSIONS: Our present study showed that varying the peritoneal dwell time was a patient-friendly UF data collection protocol for continuous ambulatory peritoneal dialysis patients on a fixed dialysis schedule. Applying the fluid transport model and nonlinear least squares regression analysis to pooled UF values might be a good and simple way to predict the peritoneal UF capacity.

Defining peritoneal dialysis adequacy: Kt/Vurea revisited.

BACKGROUND: Although adequate peritoneal dialysis is not well defined, Kt/Vurea has been used as an index, and various values have been proposed. However, conflicting evidence existed regarding the appropriateness of using Kt/Vurea to define dialysis adequacy and its optimal value. Therefore, the present study performed a theoretical analysis on whether we should use Kt/Vurea to define peritoneal dialysis adequacy and what the optimal value should be. METHODS: The three-pore model was applied to evaluate the transport patterns of different molecular weight solutes and fluid. Optimal Kt/Vurea value was estimated based on urea kinetics and nitrogen balance. RESULTS: The removal pattern of small solute, middle and large molecules, and fluid and sodium are quite different. Depending on the dwell time, higher urea removal does not necessarily mean higher sodium, fluid, and other molecular weight solute removals. To reach nitrogen balance, the dialysis doses and therefore Kt/Vurea values varied with different dietary protein intakes in a patient with a given weight and residual renal function. CONCLUSION: This study shows that Kt/Vurea in peritoneal dialysis cannot represent the removal of other solutes and fluid, indicating that Kt/Vurea alone should not be used as a sole indicator of peritoneal dialysis adequacy. The results also show that optimal Kt/Vurea cannot be a fixed value, but varies according to individual dietary protein intake and tolerable blood urea level.

A simple method for the estimation of peritoneal fluid transport.

BACKGROUND: Evaluating peritoneal fluid kinetics is of great value to the adjustment of peritoneal dialysis prescription. Therefore, in the present study, we developed a simple method, based on a membrane transport model, to evaluate the fluid transport characteristics of the peritoneal membrane in continuous ambulatory peritoneal dialysis (CAPD) patients. METHODS: Patients' peritoneal ultrafiltration (UF) volume was collected for 2 consecutive months. Membrane transport model and nonlinear least-squares regression analyses were applied to the pooled UF volume for the first month for fluid kinetic simulation and the data from the second month were used to evaluate the reliability and precision of simulated UF values. RESULTS: Seventeen chronic peritoneal dialysis (PD) patients were selected for the present study. Simulated UF values based on the pooled UF volume in the first month correlated significantly with the actual measured UF values in the second month. By Bland-Atman plot, the width between the 95% limits of agreement fell within -133.3 to 154.2 ml with a mean difference of 10.5 ml. CONCLUSION: Our study showed that applying the fluid transport model and nonlinear least-squares regression analysis to the pooled actual UF value might be a good and simple way to predict peritoneal UF.

Metabolic acidosis in peritoneal dialysis patients: the role of residual renal function.

BACKGROUND: Metabolic acidosis (MA) is common in chronic renal insufficiency (CRI) patients, and its pattern changes as renal function deteriorates. Although the prevalence of acidosis in peritoneal dialysis has been reported to be rather high, the causes of it have not been well studied. The present study was performed to examine the prevalence of metabolic acidosis in our continuous ambulatory peritoneal dialysis (CAPD) patients and its possible causes. METHODS: In this cross-sectional study, we analyzed data from patients who received maintenance CAPD in our hospital and had been on dialysis for at least one month. Patients' demographic features, medications, and intercurrent medical conditions were recorded. Data including blood biochemistry, dialysis adequacy, and nutrition were collected. A serum bicarbonate concentration of less than 23 mmol/l was defined as having acidosis. The normal value of the serum anion gap (AG) was defined as 12+/- 4 mmol/l. RESULTS: A total of 154 patients (76 males and 78 females) with age of 60.04+/- 13.92 years and the time on dialysis of 16.83+/- 21.59 months were included in this study. Sixty-six patients (43%) had a serum bicarbonate of less than 23 mmol/l, among whom 12 patients (8%) were identified as having MA with increased AG, 54 (35%) were identified as having MA with normal AG. Patients who had better residual renal function (RRF) had a significantly lower serum bicarbonate level despite their higher total KT/V(urea) as compared to those with lower RRF. In addition, patients with MA and normal AG had the highest RRF and highest total KT/V(urea). All patients with MA and increased AG had significantly lower values of dietary protein intake (DPI) as compared to their values of normalized protein nitrogen appearance (nPNA), and had higher serum urea and phosphate levels as compared with those patients without MA. CONCLUSION: Our study suggested that CAPD patients with better RRF were more susceptible to metabolic acidosis, which was characterized by normal anion gap and hyperchloremia. Thus, we speculate that renal loss of bicarbonate may to a large extent be responsible for the occurrence of MA in these patients.