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PubMed2000

Ultrafiltration with icodextrins in continuous ambulatory peritoneal dialysis and automated peritoneal dialysis.

Icodextrins (Icos) produce constant linear ultrafiltration (UF). This effect allows Icos to replace glucose during long dwells in continuous ambulatory peritoneal dialysis [CAPD (nighttime)] and automated peritoneal dialysis [APD (daytime)]. However, the effectiveness of Icos in producing UF (IcoUF) is limited by lymphatic reabsorption, whose extent depends partly on posture and physical activity. This paper aims to assess whether the difference in posture and physical activity between daytime dwells in APD and nighttime dwells in CAPD affects IcoUF. Patients undergoing first treatment were retrospectively examined. Ten patients were on CAPD [4 males, 6 females; average age, 73.0 +/- 13.4 years; body surface area (BSA), 1.63 +/- 0.21 m2; total volume per day, 5.6 +/- 1.9 L], and ten were on APD (7 males, 3 females; average age, 67.7 +/- 9.8; BSA, 1.75 +/- 0.22 m2; total volume per night, 10.5 +/- 0.9 L). Ultrafiltration was assessed for seven consecutive days preceding a peritoneal equilibration test (PET) and collection of diuresis. In both groups, 3 patients had no diuresis, and the difference between CAPD and APD was not significant (625 +/- 762 mL vs 780 +/- 878 mL). Moreover, no significant difference was seen in 4-hour dialysate-to-plasma creatinine (D/P) between CAPD (0.65 +/- 0.12) and APD (0.64 +/- 0.05). Dwell times with Icos were shorter in CAPD than in APD (11.5 +/- 1.8 hours vs 14.8 +/- 0.5 hours, p < 0.0005), but the fill volume was not significantly different (1760 +/- 286 mL vs 1790 +/- 249 mL). Water excretion owing to diuresis and dialysis [total water excretion (TWE): 1619 +/- 497 mL CAPD vs 1762 +/- 736 mL APD] and dialytic UF (363 +/- 443 mL CAPD vs 748 +/- 479 mL APD), which is not linked to Icos, were not significantly different between the two groups. The IcoUF and the percentage of IcoUF to TWE were significantly higher in CAPD compared to APD [631 +/- 253 mL (44% +/- 27%) vs 234 +/- 215 mL (19% +/- 19%), p < 0.001 (p < 0.05)]. In conclusion, an upright posture and physical activity seem to produce less IcoUF in APD despite the longer dwell. These factors could, indeed, produce greater intraperitoneal pressure, resulting in increased lymphatic reabsorption during a daytime dwell.

Aged↗
PubMed1999

[Effects of bone marrow endothelial cell conditioned medium and its ultrafiltration-prepared components on the growth of CFU-GM].

In this study, we obtained the serum-free conditioned medium from subcultures of murine bone-marrow-derived endothelial cell line which has been established recently by ourselves. And then, molecular weight (MW) > 10 kD, 3-10 kD, 1-3 kD, 0.5-1 kD and < 0.05 kD components were sifted out from the conditioned medium (mBMEC-CM) by means of serial ultrafiltration. Assays of granulocyte-macrophage colony-forming cell (CFU-GM) were performed to examine the effects of mBMEC-CM and its ultrafiltration-prepared components. It was not observed that mBMEC-CM and MW 3-10 kD component had any significant influence on the growth of CFU-GM. However, MW > 10 kD and 0.5-1 kD components enhanced the proliferation of CFU-GM, whereas MW 1-3 kD and < 0.5 kD ones inhibited it. All these four components exerted their effects on the growth of CFU-GM in dose-dependent way. Our observations suggest that under the conditions of in vitro, murine bone marrow endothelial cells produce several active components which have promoting or inhibitory effects on the growth of CFU-GM.

Animals↗
PubMedDate not supplied

Ultrafiltration and dialysate sodium profiling: choosing the optimal therapy for your patients.

Impaired vascular refilling and declining plasma osmolality contribute to the incidence of complications during hemodialysis therapy. Interventions such as ultrafiltration and dialysate sodium profiling can be utilized to make dialysis treatments more effective and comfortable for patients. Selecting appropriate profiles requires careful clinical assessment and an understanding of the principles supporting these interventions. This paper describes fluid distribution and factors influencing vascular refilling during hemodialysis. The principles of ultrafiltration and dialysate sodium profiling are discussed and validated. Guidelines for clinical assessment and selection of profiles are presented.

Decision Making↗
PubMed1992

Blood flow, ultrafiltration and solute transport rate in continuous arteriovenous haemodiafiltration: the AN-69 flat-plate haemofilter.

We measured blood flow, ultrafiltration rate and uraemic solute clearance at different dialysate flow rates during CAVHD using the AN-69 0.43 m2 flat plate haemofilter. As filter performance depends on clinical conditions and operational characteristics, data were analysed in terms of resistance to blood flow, membrane index of ultrafiltration, and diffusive mass transfer coefficients. An attempt was made to construct nomograms that may be used both to predict filter performance and to compare different haemofilters with each other.

Biophysical Phenomena↗
PubMed1992

[Dynamics of myocardial function in the complex treatment of patients with heart failure using isolated ultrafiltration (polycardiographic data)].

Sixty patients with Stages IIB-III chronic heart failure were examined. The main group included 30 patients on complex therapy involving isolated ultrafiltration (IUF), the other 30 patients who refused to have IUF comprised the control group. The patients from the main group had improvement in the phasic pattern of a cardiac cycle, which was associated with enhanced myocardial contractility and performance due to decreased preload. Improved phasic parameters observed after IUF sessions were sustained in the post-ultrafiltration period and different from those in the control group in which their significant changes were absent during treatment.

Cardiac Glycosides↗
PubMed1992

Peritoneal ultrafiltration after chronic exposure to dialysis fluid.

Eleven rats were given twice-daily intraperitoneal injections of 20 mL of dialysis fluid containing 4.5% glucose for 6 weeks. The peritoneal ultrafiltration capacity of this group was compared with that of a control group of 10 rats that had received no injections by measuring the volume and glucose concentration of the dialysate remaining in the peritoneal cavity 2 hours after injection. Animals that had received injections of dialysis fluid showed significant loss of peritoneal ultrafiltration: volume of dialysate remaining in the control group was 31 (13-35) mL, and in the experimental group was 25 (11-45) mL, with p less than 0.02 (Mann-Whitney). This was associated with enhanced glucose absorption: glucose absorbed by the control group was 382 (312-706) mg, and 595 (435-738) mg in the experimental group (p less than 0.002, Mann-Whitney).

Animals↗
PubMed2004

Simultaneous removal of nitrate and phosphate using cross-flow micellar-enhanced ultrafiltration (MEUF).

The feasibility of cross-flow micellar-enhanced ultrafiltration (MEUF) was investigated to remove nitrate and phosphate simultaneously. At the above critical micelle concentration (CMC), a cationic surfactant added in wastewater forms micelles, which have positive charge on their surface. Anionic contaminants such as nitrate and phosphate can be bound on the micelles by electrostatic interaction, and the micelle-pollutants complex is removed effectively by ultrafiltration. In this study, a cross-flow MEUF system was designed and investigated the feasibility of MEUF for field application. A cationic surfactant, cetylpyridinium chloride (CPC), was used, and the synthetic wastewater was treated by the polyacrylonitrile membranes with molecular weight cut-off (MWCO) of 30,000 Da and 10,000 Da. With the molar ratio of CPC to total pollutants of > 3, > 86% of nitrate and > 91% of phosphate were removed, respectively, and > 97% of CPC was also rejected. The flux was maintained 20-30% of the flux of distilled water. Therefore, it is feasible to remove nitrate and phosphate simultaneously using the cross-flow MEUF system.

Acrylic Resins↗
PubMed2005

Ultrafiltration failure in peritoneal dialysis. Causes and clinical consequences.

Ultrafiltration failure (UFF) is the insufficient ability to remove excess fluid from the body by dialysis. In peritoneal dialysis (PD) this is a common complication, the frequency increases with duration of treatment. In this review a summary of peritoneal transport mechanisms and the conditions associated with UFF are discussed. The 2 most common circumstances in which ultrafiltration failure occurs, peritonitis and long-term PD treatment, are outlined more extensively. In addition a diagnostic approach and therapeutic options for the different causes of UFF are given.

Humans↗
PubMed2005

Using an improved 1D boundary layer model with CFD for flux prediction in gas-sparged tubular membrane ultrafiltration.

Tubular membrane ultrafiltration and microfiltration are important industrial separation and concentration processes. Process optimisation requires reduction of membrane build-up. Gas slug introduction has been shown to be a useful approach for flux enhancement. However, process quantification is required for design and optimisation. In this work we employ a non-porous wall CFD model to quantify hydrodynamics in the two-phase slug flow process. Mass transfer is subsequently quantified from wall shear stress, which was determined from the CFD. The mass transfer model is an improved one-dimensional boundary layer model, which empirically incorporates effects of wall suction and analytically includes edge effects for circular conduits. Predicted shear stress profiles are in agreement with experimental results and flux estimates prove more reliable than that from previous models. Previous models ignored suction effects and employed less rigorous fluid property inclusion, which ultimately led to under-predictive flux estimates. The presented model offers reliable process design and optimisation criteria for gas-sparged tubular membrane ultrafiltration.

Bioreactors↗
PubMed2005

The difference in causes of early and late ultrafiltration failure in peritoneal dialysis.

OBJECTIVE: Ultrafiltration failure (UFF) is a major complication of peritoneal dialysis. Although it seems associated with long-term treatment, it can also occur in recently started patients. To identify the causes of this complication in patients with early and late UFF we studied a group of 48 patients. Patients were classified as early if they had been treated for less than 2 years and as late if they had been treated for more than 4 years. METHOD: The patients were studied using a standard peritoneal permeability analysis. They all had a net ultrafiltration of less than 400 mL after a 4-hour dwell with 3.86% glucose. As possible causes for UFF, the solute transport parameters dialysate-to-plasma ratio (D/P) and mass transfer area coefficient of creatinine were compared, as well as the effective lymphatic absorption rate (ELAR) and the maximum dip in D/P sodium as an assessment of osmotic conductance to glucose. RESULTS: 25 short-term patients were compared with 23 long-term patients. Both groups showed an equal distribution of high small solute transport rates as a cause of UFF. The chi-square test showed that a high ELAR was a more frequent cause in early UFF compared to late UFF. However, a decreased osmotic conductance to glucose was significantly more often observed in late UFF. Some patients showed more than one cause of the complication. CONCLUSION: This study has shown that UFF in long-term patients is often caused by a decreased osmotic conductance to glucose, most likely caused by a dysfunction of peritoneal water channels in combination with increased peritoneal surface area. In short-term patients, aquaporin dysfunction is rare, but a high ELAR was a very important factor in the occurrence of UFF.

Adult↗
PubMed2005

Effluent treatment by multi-media filtration, microfiltration and ultrafiltration: results of a pilot investigation at WWTP Hoek van Holland.

Upgrading of wastewater treatment plant (WWTP) effluent as a part of the Dutch governmental policy to close the water cycle has increasing interest now. The Water Board Hoogheemraadschap van Delfland together with the project team of Witteveen + Bos Consulting Engineers, Delft University of Technology and Rossmark water treatment investigated the reuse possibilities of WWTP effluent in the region of Delfland. Therefore pilot research was carried out at WWTP Hoek van Holland applying different filtration techniques: multi-media filtration, micro- and ultrafiltration. The results show stable process performances of the different filtration techniques when proper pre-treatment was applied. For microfiltration the filtration characteristics were strongly influenced by particles which were not retained in the multi-media filter. For ultrafiltration the filtration characteristics were strongly influenced by organic components < 0.2 microm. The upgraded WWTP effluent could not be used directly as process water or for agriculture purposes, due to high concentrations of COD and salts in the WWTP effluent and filtrates. However WWTP effluent or floc filtrate could be applied directly as water for the washing of sea-sand.

Filtration↗
PubMedDate not supplied

Vaccination of turkeys with cell-free culture filtrate of Pasteurella multocida: effects of ultrafiltration and endotoxin removal.

Cell-free culture filtrate (CCF) of Pasteurella multocida strain R44/6 (serotype 3/4/9/12) was fractionated by ultrafiltration into fractions of less than 10,000, greater than 10,000, greater than 30,000, and 10,000 to 30,000 molecular weight (MW). The less-than-10,000-MW fraction contained little endotoxin comparable to bacteriologic medium; the 10,000-to-30,000-MW fraction had a moderate amount of endotoxin, whereas the greater-than-10,000- and greater-than-30,000-MW fractions contained high levels of endotoxin. Following ultrafiltration, each fraction, except the less-than-10,000-MW fraction, was divided into two equal parts, and endotoxin was removed from one part. Turkeys were vaccinated with the various MW fractions of CCF, with and without endotoxin, via the air sacs at 6 and 9 weeks of age and compared with negative controls given bacteriologic medium and positive controls vaccinated with a commercial bacterin. Before oral challenge with strain P-1059 (serotype 3) at 12 weeks of age, antibody titers were detected only in positive control turkeys. Protection against challenge, as measured by post-challenge mortality and body-weight gain, was provided by the greater-than-10,000-, greater-than-30,000-, and 10,000-to-30,000-MW fractions containing endotoxin and the commercial bacterin. Turkeys that had been vaccinated with bacteriologic medium and the four different fractions without endotoxin were not protected. Results indicated that endotoxin in CCF of P. multocida is critical in protecting turkeys from pasteurellosis.

Air Sacs↗
PubMed2005

Fentanyl plasma levels after modified ultrafiltration in infant heart surgery.

Modified ultrafiltration (MUF) is a novel application of ultrafiltration to remove excess water after cardiopulmonary bypass in pediatric patients that was first reported in 1991. It has gained widespread use as an important adjunct to fluid management in neonates, infants, and pediatric cardiac surgery patients. Now more than two decades after its original description, the exact mechanism of action and effects of this therapy are still a matter of discussion. The aim of this study was to determine the effects of MUF on plasma fentanyl levels using a two-phase in vitro and in vivo study. We designed an in vitro experimental model to simulate MUF that allowed measurement of plasma fentanyl levels while eliminating biologic variables. Plasma fentanyl levels were measured during five consecutive operations on neonates and infants undergoing repair of congenital heart defects. Increases in plasma fentanyl levels were found in vitro as well as in vivo. Fentanyl plasma levels more than doubled after MUF (increased by a factor of 2.22, from 12.4 to 27.5 ng/ml in vivo). The increase in plasma fentanyl levels needs to be taken into account when delivering anesthetic care and when analyzing the effect of MUF on outcome variables.

Cardiopulmonary Bypass↗
PubMedDate not supplied

[Concentration of medium molecular weight components in serum and ultrafiltrate in patients with chronic renal failure].

Comparable assays of medium molecular weight components in both serum and its ultrafiltrate in dialysed patients have shown, that an increase of such compounds levels in dialysis fluid is accompanied with their increase in the ultrafiltrate. No relationship between urea and medium molecular weight compounds content in both dialysate and serum was found.

Adult↗
PubMedDate not supplied

What is the optimal dwell time for maximizing ultrafiltration with icodextrin exchange in automated peritoneal dialysis patients?

BACKGROUND: Icodextrin is increasingly being used in automated peritoneal dialysis (APD) for the long dwell exchange to maintain adequate ultrafiltration (UF). However, the UF reported in the literature varies with different dwell times: from 200 to 500 mL with 12 - 15 hour dwells. In order to maximize UF, it is important to know the relationship between dwell time and UF when using icodextrin in APD patients. With this knowledge, decisions can be made with respect to dwell period, and adjustments to the dialysis prescription can be made accordingly. METHODS: We prospectively studied this relationship in 36 patients from Canada and Turkey. All patients did the icodextrin day exchange manually after disconnecting themselves from overnight cycler dialysis. Dwell period was increased by 1 hour every week, from 10 to 14 hours. Ultrafiltration was noted for each icodextrin exchange. Mean UF for each week (i.e., dwell period) was compared by repeated measures ANOVA. RESULTS: We found no difference in mean UF with increasing dwelt time: 351.73 +/- 250.59 mL at 10 hours versus 371.75 +/- 258.25 mL at 14 hours (p = 0.83). We also compared mean UF between different subgroups and found that males (p = 0.02 vs females) and high transporters (p = 0.04 vs low) had higher mean UF. Further analysis of maximal UF showed no correlation to age, sex, diabetic status, transport category, creatinine clearance, Kt/V, duration on peritoneal dialysis, or duration of icodextrin use. CONCLUSION: Icodextrin-related UF in APD patients is not related to demographic factors and does not increase significantly beyond 10 hours.

Adult↗
PubMed2006

Effects of conventional ultrafiltration on renal performance during adult cardiopulmonary bypass procedures.

Ultrafiltration has been used successfully in a variety of applications in the perioperative setting to assist in hemoconcentration and volume reduction. This study was designed to investigate the effects of aggressive conventional hemofiltration on bypass urine production, fluid balance, and renal performance in the 24 hours after bypass procedures in the adult population. A prospective, randomized study was designed to determine the effects of conventional ultrafiltration (CUF) during bypass while monitoring urine dynamics intraoperatively and in the 24-hour post-bypass period. Study group 1 (CUF, n = 49) was compared to control group 2 (non-CUF, n = 47) by monitoring urine values, volume additions, and packed red cell (PRC) use throughout the procedure. The mean total CUF volume removed from group 1 was 5781 +/- 2612. There were no differences in pre-bypass, total bypass, or total operating room (OR) urine between the two groups. The 24-hour urine totals were significantly higher in group 2 (2389 +/- 895) than in group 1 (2035 +/- 895). The ending bypass hematocrit was also lower in group 2 (26 +/- 2.0) than in group 1 (30 +/- 6.0). OR PRC additions were higher in group 2 (395 +/- 699) than group 1 (204 +/- 300). The non-CUF control group 2 experienced significantly greater ending fluid balance (3006 +/- 868) compared with group 1 (744 +/- 1271). No significant differences in pre- or postoperative creatinine values were observed. Aggressive CUF can be safely used during cardiopulmonary bypass in the adult population to reduce fluid accumulation and elevate bypass hematocrit without effecting bypass or intraoperative urine production.

Aged↗
PubMed1990

Ultrafiltration to remove endotoxins and other cytokine-inducing materials from tissue culture media and parenteral fluids.

The presence of small amounts of endotoxins are often undesirable when investigating cytokines such as interleukin-1 and tumor necrosis factor alpha. Polymyxin B, widely used to block endotoxins, does not block several forms of endotoxins, and at high concentrations, polymyxin B itself stimulates interleukin-1 production. Human peripheral blood mononuclear cells are highly sensitive to endotoxins; they respond with cytokine production to endotoxins at concentrations of 10-50 pg/ml and detect pyrogenic materials nonreactive in the Limulus test. In the present study, ultrafiltration using polysulfone filters was found to remove all interleukin-1- and tumor necrosis factor alpha-inducing substances produced in E. coli cultures. Interleukin-1- and tumor necrosis factor alpha-inducing substances derived from Pseudomonas aeruginosa cultures were also rejected by the filters. Ultrafiltration is therefore a convenient and effective procedure to remove interleukin-1 and tumor necrosis factor alpha-inducing substances from parenteral fluids and solutions that come in contact with blood such as fluids used in hemodialysis. This technique is also applicable for the large-scale production of culture media for mammalian cell expression of recombinant, pyrogen-free proteins intended for use in humans.

Biological Factors↗
PubMed1991

[Central and peripheral hemodynamics in patients with heart failure treated with isolated ultrafiltration (rheographic data)].

A total of 30 patients with Stage IIB-III (by the classification made by V. Kh. Vasilenko and N. D. Strazhesko) heart failure were studied. The preload decrease resulted from isolated ultrafiltration sessions was found to lead to improved central and peripheral hemodynamic parameters, as evidenced by higher cardiac output that caused a reduction of total peripheral vascular resistance. With the multimodality therapy performed in the postultrafiltration period, the reduced total peripheral vascular resistance was followed by diminished edema of parenchymal organs. In the postinfiltration period, the isolated ultrafiltration-induced improvement in peripheral hemodynamic parameters was associated with abundant fluid transition from the interstitial space and with a profound decrease in tissue edema and pressure.

Aged↗