scholarly journals Measuring Peritoneal Absorption with the Prolonged Peritoneal Equilibration Test from 4 to 8 Hours Using Various Glucose Concentrations

2014 ◽  
Vol 34 (6) ◽  
pp. 605-611 ◽  
Author(s):  
Josep Teixidó–Planas ◽  
Maria Isabel Troya–Saborido ◽  
Guillermo Pedreira–Robles ◽  
Milagros Del-Rio–Lafuente ◽  
Ramon Romero–Gonzalez ◽  
...  
Keyword(s):  
Water Transport ◽  
Peritoneal Fluid ◽  
Glucose Solution ◽  
Free Water ◽  
Random Order ◽  
Practical Method ◽  
University Hospital ◽  
Transport Parameters ◽  
Peritoneal Equilibration Test ◽  
Small Pore

BackgroundPeritoneal fluid flows such as small-pore ultrafiltration and free water transport can now be calculated by means of the modified peritoneal equilibration test (PET). To calculate peritoneal fluid absorption, volume markers have been used, but that method is not easily applicable in clinical practice. Alternatively, absorption can be estimated using the personal dialysis capacity test. However, a method of measuring overall peritoneal absorption together with the PET is lacking. The aim of the present study was to assess whether overall peritoneal absorption was different when measured from the 4th to 8th hour in a prolonged PET using three different glucose solutions.MethodsThe study enrolled 32 stable peritoneal dialysis (PD) patients from a tertiary university hospital, who underwent three 8-hour prolonged PETs with 1.36%, 2.27%, and 3.86% glucose solution. The PETs were performed in random order over a period of less than 1 month. During the prolonged PET, the peritoneal volume was emptied and reinfused at 60 and 240 minutes and drained at 480 minutes. Peritoneal absorption was calculated as the volume difference between the 4th and the 8th hour.ResultsThe dialysate-to-plasma ratio (D/P) of urea, the D/P creatinine, and the mass transfer area coefficient (MTC) of creatinine at 240 minutes were not significantly different with the three glucose solutions. The end-to-initial (D/D0) glucose, MTC urea, and MTC glucose were significantly different. All water transport parameters were significantly different, except for the 4- to 8-hour absorption volumes and rates. The peritoneal absorption rates were, for 1.36% solution, 1.03 ± 0.58 mL/min [95% confidence interval (CI): 0.83 to 1.24 mL/min]; for 2.27% solution, 0.86 ± 0.71 mL/min (95% CI: 0.61 to 1.11 mL/min); and for 3.86% solution, 1.05 ± 0.78 mL/min (95% CI: 0.77 to 1.33 mL/min). Peritoneal absorption volumes and rates from the 4th to the 8th hour showed good correlations for the various solutions.ConclusionsUsing any glucose solution, the prolonged PET with voiding and reinfusion at the 4th hour could be a practical method for calculating overall peritoneal absorption from the 4th to the 8th hour in PD patients.

Validation by Computer Simulation of Two Indirect Methods for Quantification of Free Water Transport in Peritoneal Dialysis

2005 ◽  
Vol 25 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Daniele Venturoli ◽  
Bengt Rippe
Keyword(s):  
Peritoneal Dialysis ◽  
Water Transport ◽  
Free Water ◽  
Hydraulic Permeability ◽  
Nephrol Dial Transplant ◽  
Peritoneal Equilibration Test ◽  
Simple Method ◽  
Sodium Removal ◽  
Relative Contribution ◽  
Small Pore

Background In peritoneal dialysis, approximately 40% of the total osmotic ultrafiltration (UF) induced by glucose can be predicted to be due to “free” water transport across aquaporin-1 (APQ-1). Theoretically, it would be possible to assess the fraction of free water transport in the early phase of a hypertonic dwell, when UF rate is high and the relative contribution of Na+ diffusion is low. La Milia et al. [La Milia V. et al. Fast-fast peritoneal equilibration test (FAST-FAST-PET): a simple method for peritoneal hydraulic permeability study [Abstract]. Nephrol Dial Transplant 2002; 17 (Suppl 1):17–18] suggested a technique to assess sodium-associated water transport based on sodium removal (Na+R) divided by the plasma Na+ concentration during a “fast-fast” (60 minute) peritoneal equilibration test (PET) for 3.86% glucose, yielding an estimate of the UF passing through the small pores (UFSP). Free water transport (UF through ultrasmall pores; UFUSP) was obtained by subtracting UFSP from total UF. Although peritoneal Na+ transport is almost totally convective, this technique will slightly overestimate small-pore UF due to the presence of some small-pore Na+ diffusion from the circulation during the dwell. A way of dealing with this problem was presented recently by Smit (Smit W. et al. Quantification of free water transport in peritoneal dialysis. Kidney Int 2004; 66:849–854). Methods In the present study we used the three-pore model of peritoneal transport to predict the degree of overestimation of UFSP for the technique presented by La Milia et al., and any potential deviations from theory for the technique presented by Smit et al. Simulations were performed under ordinary conditions and during simulated UF failure for 3.86% glucose. The fractional UF coefficient accounted for by APQ-1 was set at 2%. Results Estimating the UFSP from the sodium-associated water transport according to the method by La Milia et al. consistently overestimated UFSP and underestimated UFUSP. These errors were, however, minimal for dwells lasting between 30 and 80 minutes. The technique by Smit et al. to calculate aquaporin-mediated water flow (UFUSP), using an elaborate correction for Na+ diffusion from the circulation during the dwell, seemed accurate in most situations but, in general, tended to moderately overestimate UFUSP at early dwell times (<30 minutes) and underestimate UFUSP at long dwell times (4 hours). Conclusions The technique presented by La Milia et al. to calculate free water transport during a fast-fast PET was found to be surprisingly accurate, although the procedure would further improve by the introduction of a correction algorithm. The technique by Smit is even more accurate for dwells up to 4 hours’ duration. However, since the Smit technique is elaborate, it is less practical for routine determinations of aquaporin-mediated water transport in peritoneal dialysis.

Quantification of Free Water Transport during the Peritoneal Equilibration Test

2009 ◽  
Vol 29 (5) ◽  
pp. 523-527 ◽  
Author(s):  
Trijntje T. Cnossen ◽  
Watske Smit ◽  
Constantijn J.A.M. Konings ◽  
Jeroen P. Kooman ◽  
Karel M. Leunissen ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Water Transport ◽  
Peritoneal Cavity ◽  
Glucose Solution ◽  
Free Water ◽  
Peritoneal Equilibration Test ◽  
Additional Information

Objective Free water transport (FWT) can be calculated after a dwell of 1 hour with a 3.86% glucose solution using sodium kinetics (mini-PET, as developed by LaMilia et al.). This requires measurement of the intraperitoneal volume after drainage of the abdomen. Since valuable information of a 4-hour peritoneal equilibration test (PET) may be lost, the aim of the present study was to investigate whether temporary drainage of the peritoneal cavity after 1 hour and re-instillation thereafter would influence the results of the 4-hour PET. Methods and Patients Two PETs were performed in 10 stable peritoneal dialysis (PD) patients (mean age 59 ± 13 years, mean duration on PD 33 ± 15 months) within a mean period of 54 (range 13 – 104) days: one standardized 4-hour PET using 3.86% glucose (PET A) and one with drainage after 1 hour followed by re-instillation (PET B). Results Mean total ultrafiltration (UF) of PETs A and B was 667 ± 210 mL and 621 ± 206 mL (NS). Mean FWT at 60 minutes was 164 ± 74 mL and mean UF through the small pores was 204 ± 181 mL; FWT correlated well with total UF ( r = 0.720, p = 0.019). Classification of transport categories was identical for 9 of the 10 patients. Comparison of 1-hour and 4-hour results in test B showed a good correlation between dialysate-to-plasma ratios (D/P) of creatinine and urea and Dt/D0 ratios of glucose. Conclusion A 4-hour 3.86% glucose PET, including temporary drainage after 1 hour for assessment of free water transport, does not influence the results of D/P creatinine or Dt/D0 glucose and gives essential additional information on aquaporin function.

scholarly journals Time Course of Peritoneal Function in Automated and Continuous Peritoneal Dialysis

2012 ◽  
Vol 32 (6) ◽  
pp. 605-611 ◽  
Author(s):  
Wieneke M. Michels ◽  
Marion Verduijn ◽  
Alena Parikova ◽  
Elisabeth W. Boeschoten ◽  
Dirk G. Struijk ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Repeated Measures ◽  
Time Course ◽  
Fluid Transport ◽  
Free Water ◽  
Transport Parameters ◽  
Lymphatic Absorption ◽  
Small Pore ◽  
Year 2000 ◽  
Over Time

♦ Background and ObjectivesIn automated peritoneal dialysis (APD), a patient's peritoneal membrane is more intensively exposed to fresh dialysate than it is in continuous ambulatory peritoneal dialysis (CAPD). Our aim was to study, in incident peritoneal dialysis (PD) patients, the influence of APD—compared with that of CAPD—on peritoneal transport over 4 years.♦ Design, Setting, Participants, and MeasurementsPatients were included if at least 2 annual standard permeability analyses (SPAs) performed with 3.86% glucose were available while the patient was using the same modality with which they had started PD (APD or CAPD). Patients were followed until their first modality switch. Differences in the pattern of SPA outcomes over time were tested using repeated-measures models adjusted for age, sex, comorbidity, primary kidney disease, and year of PD start.♦ ResultsThe 59 CAPD patients enrolled were older than the 47 APD patients enrolled (mean age: 58 ± 14 years vs 49 ± 14 years; p < 0.01), and they had started PD earlier (mean start year: 2000 vs 2002). Over time, no differences in solute ( p > 0.19) or fluid transport ( p > 0.13) were observed. Similarly, free water transport ( p = 0.43) and small-pore transport ( p = 0.31) were not different between the modalities. Over time, patients on APD showed a faster decline in effective lymphatic absorption rate (ELAR: p = 0.02) and in transcapillary ultrafiltration (TCUF: p = 0.07, adjusted p = 0.05). Further adjustment did not change the results.♦ ConclusionsCompared with patients starting on CAPD, those starting on APD experienced a faster decline in ELAR and TCUF. Other transport parameters were not different over time between the groups.

scholarly journals The contribution of free water transport and small pore transport to the total fluid removal in peritoneal dialysis

2005 ◽  
Vol 68 (4) ◽  
pp. 1849-1856 ◽  
Author(s):  
Alena Parikova ◽  
Watske Smit ◽  
Dirk G. Struijk ◽  
Machteld M. Zweers ◽  
Raymond T. Krediet
Keyword(s):  
Peritoneal Dialysis ◽  
Water Transport ◽  
Free Water ◽  
Fluid Removal ◽  
Small Pore ◽  
Total Fluid

scholarly journals Analysis of Ultrafiltration Failure Diagnosed at the Initiation of Peritoneal Dialysis with the Help of Peritoneal Equilibration Tests with Complete Drainage at Sixty Minutes. A Longitudinal Study

2016 ◽  
Vol 36 (4) ◽  
pp. 442-447 ◽  
Author(s):  
Daniela Machado Lopes ◽  
Ana Rodríguez-Carmona ◽  
Teresa García Falcón ◽  
Andrés López Muñiz ◽  
Tamara Ferreiro Hermida ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Water Transport ◽  
Time Course ◽  
Free Water ◽  
Control Group ◽  
First Year ◽  
Study Group ◽  
Ultrafiltration Failure ◽  
Small Pore

BackgroundUltrafiltration failure (UFF) diagnosed at the initiation of peritoneal dialysis (PD) has been insufficiently characterized. In particular, few longitudinal studies have analyzed the time course of water transport in patients with this complication.ObjectiveTo investigate the time course of peritoneal water transport during the first year on PD in patients presenting UFF since the initiation of this therapy (study group).MethodProspective, observational, single-center design. We analyzed, at baseline and after 1 year of follow-up, peritoneal water transport in 19 patients incident on PD with UFF. We used incident patients without UFF as a control group. Water transport was characterized with the help of 3.86/4.25% dextrose-based peritoneal equilibration tests (PETs) with complete drainage at 60 minutes.ResultsThe study group revealed a disorder of water transport affecting both small-pore ultrafiltration (SPUF) ( p = 0.054 vs incident without UFF) and free water transport (FW T) ( p = 0.001). After 1 year of follow-up, FWT displayed a general increasing trend in the study group (mean variation 48.9 mL, 95% confidence interval [CI] 15.5, 82.2, p = 0.012), while the behavior of SPUF was less predictable (-4.8 mL, 95% CI -61.4, 71.1, p = 0.85). These changes were not observed in incident patients without UFF. Neither initial clinical characteristics, baseline PET-derived parameters, or suffering peritoneal infections during the first year predicted the time course of the capacity of UF in the study group. Recovery from incident UFF was apparently linked to improvement of SPUF.ConclusionsPatients with UFF at the start of PD suffer a disorder of peritoneal water transport affecting both FWT and SPUF. Free water transport increases systematically in these patients after 1 year of follow-up. The evolution of SPUF is less predictable, and improvement of this parameter marks reversibility of this complication.

scholarly journals Free water transport, small pore transport and the osmotic pressure gradient

2008 ◽  
Vol 23 (7) ◽  
pp. 2350-2355 ◽  
Author(s):  
A. Parikova ◽  
W. Smit ◽  
M. M. Zweers ◽  
D. G. Struijk ◽  
R. T. Krediet
Keyword(s):  
Pressure Gradient ◽  
Osmotic Pressure ◽  
Water Transport ◽  
Free Water ◽  
Small Pore ◽  
Osmotic Pressure Gradient

scholarly journals Two-in-One Protocol: Simultaneous Small-Pore and Ultrasmall-Pore Peritoneal Transport Quantification

2012 ◽  
Vol 32 (5) ◽  
pp. 537-544 ◽  
Author(s):  
Ana Paula Bernardo ◽  
M. Auxiliadora Bajo ◽  
Olivia Santos ◽  
Gloria Del Peso ◽  
Maria João Carvalho ◽  
...  
Keyword(s):  
Free Water ◽  
Peritoneal Membrane ◽  
Peritoneal Equilibration Test ◽  
Indirect Measurements ◽  
Ultrafiltration Failure ◽  
Small Pore ◽  
Decisive Parameter ◽  
Sodium Sieving ◽  
Functional Deterioration ◽  
Small Solute

BackgroundReduced free water transport (FWT) through ultrasmall pores contributes to net ultrafiltration failure (UFF) and should be seen as a sign of more severe functional deterioration of the peritoneal membrane. The modified peritoneal equilibration test (PET), measuring the dip in dialysate Na concentration, estimates only FWT. Our aim was to simultaneously quantify small-solute transport, FWT, and small-pore ultrafiltration (SPUF) during a single PET procedure.MethodsWe performed a 4-hour, 3.86% glucose PET, with additional measurement of ultrafiltration (UF) at 60 minutes, in 70 peritoneal dialysis patients (mean age: 50 ± 16 years; 61% women; PD vintage: 26 ± 23 months). We calculated the dialysate-to-plasma ratios (D/P) of creatinine and Na at 0 and 60 minutes, and the Na dip (DipD/PNa60,), the delta dialysate Na 0–60 (ΔDNa0–60), FWT, and SPUF.ResultsSodium sieving (as measured by ΔDNa0–60) correlated strongly with the corrected DipD/PNa60, ( r = 0.85, p < 0.0001) and the corrected FWT ( r = 0.41, p = 0.005). Total UF showed better correlation with FWT than with indirect measurements of Na sieving ( r = 0.46, p < 0.0001 for FWT; r = 0.360, p < 0.0001 for DipD/PNa60,). Corrected FWT fraction was 0.45 ± 0.16. A negative correlation was found between time on PD and both total UF and FWT ( r = -0.253, p = 0.035 and r = -0.272, p = 0.023 respectively). The 11 patients (15.7%) diagnosed with UFF had lower FWT (89 mL vs 164 mL, p < 0.05) and higher D/P creatinine (0.75 vs 0.70, p < 0.05) than did the group with normal UF. The SPUF correlated positively with FWT in the normal UF group, but negatively in UFF patients ( r = -0.709, p = 0.015). Among UFF patients on PD for a longer period, 44.4% had a FWT percentage below 45%.ConclusionsMeasurement of FWT and SPUF is feasible by simultaneous quantification during a modified 3.86% glucose PET, and FWT is a decisive parameter for detecting causes of UFF in addition to increased effective capillary surface.

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