A comparison of solute clearance and ultrafiltration volume in peritoneal dialysis with total or fractional (50%) intraperitoneal volume exchange with the same dialysate flow rate

This paper summarizes the basis of prescription for automated peritoneal dialysis (APD) established during a French national conference on APD. Clinical results and literature data show that peritoneal clearances are closely determined by peritoneal permeability and hourly dialysate flow rate, independently of dwell time or number of cycles. With APD, peritoneal creatinine clearance increases according to the hourly dialysate flow rate to a maximum (plateau), then decreases because of the multiplication of the drain-fill times. The hourly dialysate flow giving the maximum peritoneal creatinine clearance is defined as the “maximal effective dialysate flow” (MEDF). MEDF is higher for high peritoneal permeabilities: MEDF is 1.8 and 4.2 L/hr with nocturnal tidal peritoneal dialysis (TPD) for a 4-hr creatinine dialysate-to-plasma ratio (DIP) of 0.50 and 0.80, respectively. With nightly intermittent peritoneal dialysis (NIPD), MEDF is 1.6 and 2.3 Llhr for a DIP of 0.50 and 0.78, respectively. Under these conditions, tidal modalities can only be considered as a way to increase the MEDF. Using the MEDF concept for an identical APD session duration, the maximal weekly normalized peritoneal creatinine clearance can vary by 340% when 4hr DIP varies from 0.41 to 0.78. APD is not recommended when 4-hr creatinine DIP is lower than 0.50. However, the limits of this technique may be reached at higher peritoneal permeabilities in anurics because of the duration of sessions andlor the additional exchanges required by these patients.

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Computer Simulations of Continuous Flow Peritoneal Dialysis Using the 3-Pore Model—A First Experience

Peritoneal Dialysis International ◽

10.3747/pdi.2018.00225 ◽

2019 ◽

Vol 39 (3) ◽

pp. 236-242 ◽

Cited By ~ 1

Author(s):

Carl M. Öberg ◽

Giedre Martuseviciene

Keyword(s):

Peritoneal Dialysis ◽

Flow Rate ◽

In Silico ◽

Continuous Flow ◽

High Volume ◽

Dialysis Fluid ◽

Pore Model ◽

Dialysate Flow ◽

Dialysate Flow Rate

Background Continuous flow peritoneal dialysis (CFPD) is performed using a continuous flux of dialysis fluid via double or dual-lumen PD catheters, allowing a higher dialysate flow rate (DFR) than conventional treatments. While small clinical studies have revealed greatly improved clearances using CFPD, the inability to predict ultrafiltration (UF) may confer a risk of potentially harmful overfill. Here we performed physiological studies of CFPD in silico using the extended 3-pore model. Method A 9-h CFPD session was simulated for: slow (dialysate to plasma creatinine [D/P crea] < 0.6), fast (D/P crea > 0.8) and average (0.6 < D/P crea < 0.8) transporters using 1.36%, 2.27%, or 3.86% glucose solutions. To avoid overfill, we applied a practical equation, based on the principle of mass-balance, to predict the UF rate during CFPD treatment. Results Increasing DFR > 100 mL/min evoked substantial increments in small- and middle-molecule clearances, being 2 - 5 times higher compared with a 4-h continuous ambulatory PD (CAPD) exchange, with improvements typically being smaller for average and slow transporters. Improved UF rates, exceeding 10 mL/min, were achieved for all transport types. The β2-microglobulin clearance was strongly dependent on the UF rate and increased between 60% and 130% as a function of DFR. Lastly, we tested novel intermittent-continuous regimes as an alternative strategy to prevent overfill, being effective for 1.36% and 2.27%, but not for 3.86% glucose. Conclusion While we find substantial increments in solute and water clearance with CFPD, previous studies have shown similar improvements using high-volume tidal automated PD (APD). Lastly, the current in silico results need confirmation by studies in vivo.

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A Comparison of Clearances on Tidal Peritoneal Dialysis and Intermittent Peritoneal Dialysisa

Peritoneal Dialysis International ◽

10.1177/089686089401400209 ◽

1994 ◽

Vol 14 (2) ◽

pp. 145-148 ◽

Cited By ~ 29

Author(s):

Beth Piraino ◽

Filitsa Bender ◽

Judith Bernardini

Keyword(s):

Peritoneal Dialysis ◽

Small Molecule ◽

Flow Rate ◽

Peritoneal Equilibration Test ◽

Urea Nitrogen ◽

Dialysate Flow ◽

Dialysate Flow Rate ◽

Fill Volume ◽

The Mean ◽

Tidal Peritoneal Dialysis

Objectives To compare the small molecule clearances on tidal peritoneal dialysis (TPD) and intermittent peritoneal dialysis (IPD), controlling for dialysate flow rate. Design Alternating 8-hour treatments on IPD and TPD (2 of each in 6 patients), each treatment separated by 3 or more days [patients returning to continuous ambulatory peritoneal dialysis (CAPD) in the interim] were performed. IPD treatments consisted of 15 exchanges with 2 Llexchange for a total of 30 Lltreatment. TPD treatments consisted of 29 exchanges, with an initial fill volume of 2 L, followed by 1 L tidal volume for the subsequent exchanges (reserve volume of 1 L) for a total of 30 Lltreatment. Patients Six patients, with a mean dialysatelplasma (DIP) creatinine as determined by the peritoneal equilibration test (PET) of 0.64±0.1 0, were studied. Four had a low -average DIP creatinine, while 2 had a high-average DIP creatinine. Measurements Urea nitrogen, creatinine, phosphate, and potassium clearances on TPD and IPD were compared using the paired t-test. Results The dialysate flow rates were 3.7±0.1 Llhour for IPD and 3.8±0.2 Llhour for TPD. The mean dialysate dextrose was 1.9±0.5 gldL for both. The creatinine clearances were 9±2 versus 10±3 mLlminute, the urea nitrogen clearances 19±3 versus 20±3 mLlminute, and phosphate clearances 10±3 versus 11±3 mLlminute for IPD and TPD, respectively (all not different). The ultrafiltration rates were 2.9±0.9 mLlminute on IPD and 3.3±1.6 mLI minute on TPD (not different). On both IPD and TPD the clearances of urea nitrogen, creatinine, and phosphate for the 2 patients with high-average DIP creatinine were higher than for the 4 patients with low -average DIP creatinine. Conclusions When the dialysate flow rate is controlled and a TPD prescription of 1 L reserve and tidal volumes is used, the small molecule clearances on IPD are similar to those on TPD.

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Solutes removal characteristics at various effluent rates during different continuous renal replacement therapy modalities

The International Journal of Artificial Organs ◽

10.1177/0391398819836045 ◽

2019 ◽

Vol 42 (7) ◽

pp. 354-361

Author(s):

Wenyan Yu ◽

Feng Zhuang ◽

Shuai Ma ◽

Mingli Zhu ◽

Feng Ding

Keyword(s):

Fluid Flow ◽

Renal Replacement Therapy ◽

Continuous Renal Replacement Therapy ◽

Replacement Therapy ◽

Flow Rate ◽

Fluid Flow Rate ◽

Dialysate Flow ◽

Dialysate Flow Rate ◽

Continuous Hemodialysis ◽

Solute Clearance

Background:Some studies suggest the effluent as a surrogate solute removal indicator in continuous hemodialysis or hemofiltration, but the delivered clearance is frequently smaller than prescribed. This study aims at testing whether the effluent, represented by mL/kg/h, could measure solute clearance and whether increasing effluent increases clearance proportionately in continuous hemodialysis or hemofiltration.Methods:Patients treated with continuous renal replacement therapy for various diagnoses were included. The range of dialysate flow rate or substitution fluid flow rate was 1–5 L/h; solutes in the effluent and in the plasma entering the filter were measured, and the ratio of solutes in the effluent and in the plasma entering the filter and the clearance of blood urea nitrogen, creatinine, phosphate, and β2-microglobulin were calculated.Results:The ratio of solutes in the effluent and in the plasma entering the filter showed a decreasing trend with increased dialysate flow rate or substitution fluid flow rate ( p < 0.05), but solute clearance showed an increasing trend. The increase in solute clearance was less than expected from the increased effluent ( p < 0.01), and actual delivered clearance was always below the corresponding prescribed clearance ( p < 0.001).Conclusion:With increasing prescribed clearance of continuous renal replacement therapy, effluent rate overestimated the delivered clearance.

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FP507EFFECT OF DIALYSATE FLOW RATE (QD) ON SMALL AND MIDDLE MOLECULAR SOLUTE REMOVAL IN HIGH-EFFICIENCY ON-LINE HAEMODIAFILTRATION (OL-HDF)

Nephrology Dialysis Transplantation ◽

10.1093/ndt/gfv179.36 ◽

2015 ◽

Vol 30 (suppl_3) ◽

pp. iii241-iii241

Author(s):

Luciano A. Pedrini ◽

Simona Zerbi

Keyword(s):

Flow Rate ◽

High Efficiency ◽

Dialysate Flow ◽

Dialysate Flow Rate ◽

On Line

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Does the Blood Pump Flow Rate have an Impact on the Dialysis Dose During Low Dialysate Flow Rate Hemodialysis?

Blood Purification ◽

10.1159/000486843 ◽

2018 ◽

Vol 46 (4) ◽

pp. 279-285 ◽

Cited By ~ 2

Author(s):

Maxime Leclerc ◽

Clémence Bechade ◽

Patrick Henri ◽

Elie Zagdoun ◽

Erick Cardineau ◽

...

Keyword(s):

Flow Rate ◽

Blood Pump ◽

Bivariate Analysis ◽

Dialysis Dose ◽

Dialysate Flow ◽

Pump Flow ◽

Dialysate Flow Rate ◽

Pump Flow Rate ◽

A Prospective Study ◽

The Impact

We conducted a prospective study to assess the impact of the blood pump flow rate (BFR) on the dialysis dose with a low dialysate flow rate. Seventeen patients were observed for 3 short hemodialysis sessions in which only the BFR was altered (300,350 and 450 mL/min). Kt/V urea increased from 0.54 ± 0.10 to 0.58 ± 0.08 and 0.61 ± 0.09 for BFR of 300, 400 and 450 mL/min. For the same BFR variations, the reduction ratio (RR) of β2microglobulin increased from 0.40 ± 0.07 to 0.45 ± 0.06 and 0.48 ± 0.06 and the RR phosphorus increased from 0.46 ± 0.1 to 0.48 ± 0.08 and 0.49 ± 0.07. In bivariate analysis accounting for repeated observations, an increasing BFR resulted in an increase in spKt/V (0.048 per 100 mL/min increment in BPR [p < 0.05, 95% CI (0.03–0.06)]) and an increase in the RR β2m (5% per 100 mL/min increment in BPR [p < 0.05, 95% CI (0.03–0.07)]). An increasing BFR with low dialysate improves the removal of urea and β2m but with a potentially limited clinical impact.

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Myoglobin Clearance during Continuous Veno-Venous Hemofiltration with or without Dialysis

The International Journal of Artificial Organs ◽

10.1177/039139889802100406 ◽

1998 ◽

Vol 21 (4) ◽

pp. 205-209 ◽

Cited By ~ 22

Author(s):

D. Nicolau ◽

Y.S. Feng ◽

A.H.B. Wu ◽

S.P. Bernstein ◽

C.H. Nightingale

Keyword(s):

Renal Failure ◽

Animal Model ◽

Flow Rate ◽

Major Complication ◽

Viable Option ◽

Effective Technique ◽

Dialysate Flow ◽

Continuous Arteriovenous Hemofiltration ◽

Pump Rate ◽

Dialysate Flow Rate

The management of acute myoglobinuric renal failure, the major complication of rhab-domyolysis, continues to be a treatment dilemma for the clinician as limited therapeutic options are available. Previously, we have demonstrated that continuous arteriovenous hemofiltration (CAVH) is an effective technique for removing myoglobin in an animal model. In the present study, swine were administered four grams of equine myoglobin intravenously and underwent the continuous veno-venous hemofiltration (CVVH) procedure for six hours each. Animals were studied in each of the following groups: CVVH at a pump rate 100 ml/minute, CVVH at a pump rate 200 ml/minute and CVVH at a pump rate 100 ml/minute plus dialysis at a dialysate flow rate of one Liter/h. Once the filtering process was initiated there was a rapid and sustained production of ultrafiltrate in all groups. The amount of myoglobin excreted in the ultrafiltrate over the six-hour filtering period was 688, 948 and 570 mg which corresponded to 17, 24 and 14 percent of the administered dose, respectively, for the three treatments. In comparison to previous CAVH experiments, CVVH removed more circulating myoglobin and the addition of the dialysis component did not appear to improve removal. Based on these findings, it appears that the CVVH hemofiltration system is a viable option for the removal of systemic myoglobin.

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Quantitating Dialysis using two Dialysate Samples: A Simple, Practical and Accurate Approach for Evaluating Urea Kinetics

The International Journal of Artificial Organs ◽

10.1177/039139889702000803 ◽

1997 ◽

Vol 20 (8) ◽

pp. 422-427 ◽

Cited By ~ 10

Author(s):

D.S.C. Raj ◽

S. Tobe ◽

C. Saiphoo ◽

M.A. Manuel

Keyword(s):

Kinetic Parameters ◽

Flow Rate ◽

Volume Of Distribution ◽

Mean Difference ◽

Recent Analysis ◽

Altman Plot ◽

Bland Altman Plot ◽

Dialysate Flow ◽

Dialysate Flow Rate ◽

Urea Kinetics

Urea kinetics is now widely used to determine the adequacy of dialysis. Several simplified formulae are currently in use but only a few have been accepted into clinical practice because of their simplicity and ease of calculation. A recent analysis of these formulae showed that for the same set of blood urea values the calculated Kt/V can range from 1.0 to 1.5. We have developed a new dialysate-based method (2DSM) to estimate the urea kinetic parameters using dialysate and blood samples taken at the beginning and at the end of dialysis. The total urea removed (TUR) was calculated from the geometric mean of the two dialysate samples, dialysate flow rate and the duration of dialysis. The Watson formula was used to determine the volume of distribution of urea. A comparison of the 2DSM and the direct dialysate quantification (DDQ) method showed the following results (mean ± sd, n = 52): for total urea removal (TUR) 697 ± 32 vs 722 ± 37 mmol (p = 0.6, r2 = 0.928, y = 101 + 0.83 ×, mean difference 25 ± 76 mmol, see Bland-Altman plot), dialysate urea concentration (Durea) 5.55 ± 0.25 vs 5.75 ± 0.29 mmol/l (p = 0.6, r2 = 0.928, y = 0.8 + 0.82 x, mean difference 0.2 ± 0.6 mmol, see Bland-Altman plot), dialyser clearance (K) 232 ± 4.4 vs 235 ± 5.6 ml/min (p - 0.54), Kt/V 1.42 ± 0.04 vs 1.51 ± 0.04 (p = 0.21), volume of distribution of urea (Vd) 40.14 ± 1.04 vs 38.74 ± 1.2 L, (p = 0.38), and PCR 64.6 ± 2.6 vs 68.1 ± 3.1 g/day. We have developed a simple method of determining dialysate-based urea kinetics which requires two dialysate samples, one at the beginning and one at the end of dialysis and a blood sample at the midpoint of dialysis. TUR can be calculated using the dialysate flow rate and the dialysis duration and once this is known all the other kinetic parameters can be calculated.

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