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PubMed2005

Effect of modified ultrafiltration on pulmonary function after cardiopulmonary bypass.

BACKGROUND: Pulmonary dysfunction is one of the most common manifestations of inflammatory response after cardiopulmonary bypass (CPB). OBJECTIVE: This prospective randomized study was conducted to evaluate the effect of a modified ultrafiltration (MUF) technique on pulmonary function after CPB in children. METHODS: Forty patients weighing from 5 to 10 kg with congenital heart disease who required CPB for primary biventricular operative repair were prospectively randomized into two groups. The control group received conventional ultrafiltration (CUF) during CPB, and the study group received CUF and MUF. Pulmonary compliance (static and dynamic) and gas exchange capacity of the lung expressed as oxygen index, respiratory index, ventilation index, and alveolar-arterial oxygen pressure difference were measured after intubation (baseline), at the termination of CPB, at the end of MUF, on admission to the ICU, and 6 h postoperatively. RESULTS: There was no significant difference in lung compliance and gas exchange between the two groups before CPB. CPB produced a significant decrease in static and dynamic lung compliance in both groups. In the control group, static and dynamic lung compliance decreased from 1.0 +/- 0.3 to 0.90 +/- 0.3 mL/cm/kg and 0.87 +/- 0.2 to 0.71 +/- 0.1 mL/cm/kg (+/- SE) [p = 0.0002 and p = 0.002, respectively]. In the study group, static and dynamic lung compliance decreased from 1.0 +/- 0.2 to 0.89 +/- 0.03 mL/cm/kg and 0.94 +/- 0.2 to 0.77 +/- 0.1 mL/cm/kg (p = 0.002 and p = 0.002, respectively). There was no significant difference in the decrease in static (p = 0.9) or dynamic lung compliance (p = 0.3) between the two groups. MUF produced a significant immediate improvement in both static lung compliance (0.89 +/- 0.2 to 0.98 +/- 0.2 mL/cm/kg, p = 0.03) and dynamic lung compliance (0.77 +/- 0.1 to 0.93 +/- 0.2 mL/cm/kg, p = 0.007). The same was observed regarding the gas exchange capacity. CPB produced a significant decrease in lung gas exchange capacity, and MUF produced a significant immediate improvement in lung gas exchange capacity. The effect of MUF on lung compliance and gas exchange capacity was not sustained after admission to the ICU nor 6 h later postoperatively. There was no significant difference in the time of extubation between the two groups (12 +/- 3 h and 13 +/- 2 h, p = 0.4), the length of ICU stay, or the total hospital stay postoperatively. CONCLUSIONS: The use of MUF after CPB can produce an immediate improvement in lung compliance and gas exchange capacity, which may effectively minimize pulmonary dysfunction postbiventricular repair of congenital heart disease. However, these improvements are not sustained for the first 6 h postoperatively and do not reduce the duration of postoperative intubation, ICU stay, or total hospital stay.

Cardiopulmonary Bypass↗
PubMed2002

Possibilities for recycling cellulases after use in cotton processing: part II: Separation of cellulases from reaction products and released dyestuffs by ultrafiltration.

The adsorption and activity of a total cellulase (Trichoderma reesei) was measured and compared on undyed and dyed cotton fabrics. Recovery of enzymes from the reaction mixture and by desorption from the cotton substrate was evaluated. About 80% of the initial protein could be recovered. The removal of released products (soluble reducing sugars and dyes) from the treatment liquor and subsequent concentration of cellulase proteins was performed using an ultrafiltration membrane. Strong protein-dye interactions made it impossible to separate efficiently the dyes from the enzyme-containing treatment liquors. The use of surfactants did not enhance cellulase desorption from cotton fabric. Although anionic surfactants have a deactivating effect on cellulases, this effect seems to be reversible, since after ultrafiltration the cellulase activity was similar to that of enzymes desorbed with buffer only. Humicola insolens cellulases were shown to be much more sensitive to anionic surfactant than T. reesei cellulases. The use of cellulases that bind reversibly to cellulose is suggested for achieving more efficient cellulase recycling and for reducing backstaining by dye-cellulase complexes.

Adsorption↗
PubMed1997

Identification of aluminium fractions in serum using the techniques of high performance liquid chromatography, ultrafiltration and Zeeman atomic absorption spectrometry.

In order to ascertain the distribution of aluminium in normal and occupationally exposed sera, size-exclusion chromatography using two fractionation techniques was applied: gel filtration (Sephadex G-100 SF) and HPLC (TSK G4000 SW). For each of the techniques, protein profiles obtained for control and exposed sera did not differ and aluminium was found to be associated with the same fractions. Ultrafiltration of sera using Centricon concentrators having a nominal cut-off of M(r) = 10,000 confirmed the presence of high molecular mass and ultrafiltrable low molecular mass aluminium complexes in serum. Absolute quantitation and relative distribution of aluminium in the aforementioned complexes in original and spiked sera were determined using Zeeman atomic absorption spectrometry. It was found that the relative distribution of aluminium between high molecular mass and low molecular mass fractions was 79.1% and 19.6% in controls, compared to 91.3% and 8.7% in exposed sera, which is highly significant for both high molecular mass (p < 0.026) and low molecular mass (p < 0.004). After spiking both control and exposed sera with 400 micrograms/l of Al, the distribution changed. The percentage of the aluminium bound to high molecular mass increased from 79.1% to 98.9% for controls, and from 91.3% to 98.4% for exposed sera, confirming the affinity of high molecular mass proteins, especially transferrin for aluminium. On the other hand, the percentage of aluminium bound to low molecular mass decreased after spiking to 1.12% for controls and to 1.6% for exposed sera. These differences were not statistically significant. This suggests that at high concentrations of total aluminium in serum, the percentage of the aluminium bound to the low molecular mass is lower but the absolute quantity of aluminium circulating as the low molecular mass complex is increased. This low molecular mass aluminium complex is thought to play an important role in intracellular accumulation of aluminium.

Aluminum↗
PubMed2005

Ultrafiltration for acute decompensated heart failure.

For the 13th consecutive year, acute decompensated heart failure is the most common reason for admission to American hospitals. Most patients admitted for decompensated heart failure are by definition, diuretic resistant. The therapeutic objective in these patients is volume and sodium removal, and the restoration of diuretic sensitivity. In a significant proportion of patients, this objective is not met, subjecting patients to readmission for recurrent (or continued) heart failure decompensation. Ultrafiltration therapy offers the potential of greater volume and sodium removal as compared with conventional therapies in a more expeditious manner. Ultrafiltration can be accomplished safely, quickly and on a regular telemetry ward in extremely ill patients, but relies on earlier discharge with reduced readmission rates to be economically feasible.

Acute Disease↗
PubMed1993

Intraperitoneal phosphatidylcholine levels in patients on continuous ambulatory peritoneal dialysis do not correlate with adequacy of ultrafiltration.

A qualitative and quantitative study was undertaken to determine the lipid composition of dialysate effluent from patients maintained on continuous ambulatory peritoneal dialysis (CAPD). Effluent, after a 4-h, 2.27% dextrose dwell, was collected on ice, centrifuged and extracted for lipids with chloroform and methanol. Lipids were separated and identified by thin layer chromatography, and the constituent fatty acids were quantitated by gas liquid chromatography. Effluents from 10 patients were assayed at the commencement of CAPD treatment and again after 6 months of therapy. There was a significant fall in phosphatidylcholine and phospholipid concentrations (P < 0.007) with time, whereas the fatty acid compositions of these lipids remained constant. Dialysate phosphatidylcholine and phospholipid concentrations were not significantly different between seven patients with poor ultrafiltration and eight patients who had normal fluid removal. This study demonstrates that there is no relationship between dialysate phospholipid levels and the adequacy of filtration, although it corroborates previous reports of an inverse correlation between time on CAPD and dialysate lipid concentrations. These results do not support a rationale for ip phosphatidylcholine administration in patients with poor ultrafiltration.

Adult↗
PubMed1997

Effect of controlled extracorporeal blood cooling on ultrafiltration-induced blood volume changes during hemodialysis.

Considerable amounts of heat may be lost or gained through the extracorporeal circuit during hemodialysis and influence the hemodynamic stability of the dialysis patient. The effects of two levels of extracorporeal heat flux (Jtherm in W) on blood pressures and ultrafiltration-induced blood volume changes were studied in eight patients on conventional hemodialysis. Treatments were controlled automatically for mild to medium Jtherm of either -13.4 +/- 3.3 W (group A) or -30.2 +/- 3.7 W (group B) (1 W = 1 J/s = 3.6 kJ/h = 0.239 cal/s = 0.86 kcal/h) and repeated once. Values are given as mean +/- SD. With low blood flows (Qb = 251 +/- 21 ml/min), dialysate temperatures were automatically set at 37.3 +/- 0.3 degrees C (group A) and 35.3 +/- 0.2 degrees C (group B) for the two levels of Jtherm, respectively. Arterial blood temperatures increased by 0.4 +/- 0.4 degree C with mild extracorporeal cooling (group A), whereas arterial blood temperatures slightly decreased by -0.1 +/- 0.4 degree C in the group with medium negative heat flux (group B) (P < 0.01). Blood pressures tended to drop in the warm dialysate group and to remain unchanged in the cool dialysate group (P = NS). Relative blood volume changes calculated from on-line ultrasonic blood measurements were significantly larger with cool (-12.8 +/- 8.3 vol%) than with warm (-7.2 +/- 5.5 vol%, P < 0.05) dialysate, indicating reduced fluid removal from peripheral body compartments during cool hemodialysis ultrafiltration. Despite the larger reduction in intravascular volume, intradialytic hemodynamic stability was maintained with extracorporeal cooling and cool dialysate prescription.

Aged↗
PubMed1984

Ultrafiltration vs equilibrium dialysis for determination of free fraction.

The analytical basis of membrane separation in determining plasma free drug concentrations is developed from consideration of the generalised ideal mass action and conservation laws applied to thermodynamic states of differing component volumes. The intuitively surprising theoretical independence of free drug concentration with changing fractional volume of protein predicts the equivalence of final free drug concentration after uniform pre-dilution with that after equilibrium dialysis against the same volume of buffer. Similarly, the ultrafiltrate free concentration of drugs in ideal plasma binding equilibrium is theoretically constant, regardless of the extent of reduction in fractional volume of binding protein during filtration. The pitfalls in calculating free and bound fraction and concentration from equilibrium dialysis are reviewed and expressions presented to correct the major artefacts. The dilution behaviour of drugs is predicted from the normalised mass action model. Practical aspects of validating ultrafiltration free drug levels using equilibrium dialysis are outlined.

Blood Proteins↗
PubMed1982

The determination of ultrafiltrable calcium and magnesium in serum.

Ultrafiltrate of human serum was investigated in order to evaluate the serum content of calcium and magnesium. The acid and base concentrations and pH of the serum was altered through titration with HCl- or NaOH-solutions. The Pco2 was varied in the titrated serum using different carbon dioxide tensions. This was performed when serum was filtered in a recycling system. It is shown that the analysis of calcium and magnesium have to be done under anaerobic conditions or at standardized pH and Pco2 situations, as the concentrations vary with both pH and Pco2. The concentration ratio between ultrafiltrate and serum for calcium and magnesium was found to be 0.56 and 0.74 respectively at pH=7.41 and Pco2=40 mmHg.

Calcium↗
PubMed1978

Ultrafiltration followed by haemodialysis. A longterm trial and acute studies.

Separate ultrafiltration followed by haemodialysis (U.F.-H.D.) using Gambro Major or Cordis-Dow hollow-fiber dialyzers were evaluated in 10 dialysis patients over a mean period of 4 1/2 months and 455 U.F.-H.D. procedures. Fluid control was facilitated in oedematous patients but the number of hypotensive episodes during the combined procedure requiring intravenous 5% saline did not significantly decrease. No significant improvement in hypertension was noted. Ultrafiltration (U.F.) alone for acutely water overloaded, azotaemic patients proved very useful. Two to five liters of oedema fluid could be removed asymptomatically in one to three hours using transmembrane pressures of 250 to 500 mmHg and U.F. rates of 10 to 42 ml/min. Two patients became acutely and symptomatically hypotensive. One was an insulin dependent diabetic in whom 3800 ml were removed in 75 minutes and the other a hypertensive patient undergoing treatment with Minoxidil and propranolol.

Diabetes Mellitus, Type 1↗
PubMed1979

Osmotic ultrafiltration with dextran sodium sulfate potential for use in peritoneal dialysis.

Dextran sodium sulfate was evaluated in vitro as a potential non-absorbable osmotic agent for peritoneal dialysis. It was compared to poly(sodium acrylate) which has been shown previously to be effective in rats, but probably toxic. Dextran sodium sulfate induced osmotic ultrafiltration rates as high as 20 ml/min in water but only 2 ml/min in solution containing non-polymer electrolytes presumably because of Gibbs-Donnan effects. Compared to acrylate the dextran polymer has less sodium per gram, lower osmotic activity of polymer sodium, and yields less ultrafiltration at given transmembrane osmolalities. A non-toxic polymer more like acrylate would seem more promising as an osmotic agent for peritoneal dialysis.

Acrylates↗
PubMedDate not supplied

Concentration of blood coagulation factors by ultrafiltration in hollow fiber artificial kidney.

We have concentrated plasma coagulation factors by a process of ultrafiltration (UF) using a hollow fiber artificial kidney with applied negative pressure. The coagulation factors were concentrated by between 2.4 and 3.2 times, resulting in yields of 82-100%. There was no evidence of activation of coagulation factors as shown by approximately equal increases in the concentrations of all three moieties of factor VIII following ultrafiltration, and by the fact that plasma recalcification times post-UF were not increased. It is suggested that the concentrated plasma product from UF may be useful in replacement therapy.

Blood Coagulation↗
PubMed1975

Examination of cottage cheese whey proteins by scanning electron microscopy: relationship to membrane fouling during ultrafiltration.

Deposits formed on the membrane during ultrafiltration of aqueous solutions of individual whey proteins were examined under a scanning electron microscope. Gamma-globulin formed granules which agglomerated and stacked into layers to form a porous matrix on the membrane. Beta-lactoglobulin and bovine serum albumin both formed sheets on the membrane and formed multimers which were identified by sodium dodecyl sulfate gel electrophoresis. Beta-lactoglobulin also formed strands where deposits were not thick. Alpha-lactalbumin formed smooth spherical particles which did not hinder water permeation greatly. Studies of ultrafiltration rate indicated that beta-lactoglobulin and gamma-globulin were most significant in causing permeation flux decline by surface fouling.

Animals↗
PubMed2006

[Simultaneous determination of pesticides in agricultural products by LC/MS/MS using clean-up with ultrafiltration].

A method for simultaneous determination of multiple pesticide residues in agricultural products was developed by using a pretreatment with ultrafiltration, followed by liquid chromatography-tandem mass spectrometry (LC/MS/MS). The pretreatment process (extraction of pesticides from agricultural products with methanol, dilution of the extract with water, and ultrafiltration) gave recoveries in the range of 50-150% for 63 of 83 pesticides spiked at 0.25 microg/ g into 6 agricultural products. The detection limits of pesticides by LC/MS/MS were below 0.0005-0.05 micro/g. This method is useful for screening purposes and for multiresidue analysis of pesticides in agricultural products. Pesticide residues in 50 domestic crops were investigated by this method, and residues of 14 pesticides were detected in 30 crops.

Chromatography, Liquid↗
PubMed1999

Effect of ion binding on protein transport through ultrafiltration membranes.

Electrostatic interactions can have a significant impact on protein transmission through semipermeable membranes. Experimental data for the transport of bovine serum albumin (BSA) through a polyethersulfone ultrafiltration membrane were obtained in different salt solutions over a range of pH and salt concentrations. Net BSA charge under the same conditions was evaluated from mobility data measured by capillary electrophoresis. The results show that specific ionic composition, in addition to solution pH and ionic strength, can strongly affect the rate of protein transport through semipermeable ultrafiltration membranes. The effects of different ions on BSA sieving are due primarily to differences in ion binding to the protein, which leads to significant differences in the net protein charge at a given pH and ionic strength. This effect could be described in terms of an effective protein radius, which accounts for the electrostatic exclusion of the charged protein from the membrane pores. These results provide important insights into the nature of the electrostatic interactions in membrane systems.

Animals↗
PubMed1976

[Isolated ultrafiltration with dialyzer and blood pump in hydropic cardiac insufficiency].

The authors indicate the possibility of an "Isolated Ultrafiltration" in cardiologic patients only with the transportable blood conducting part of the artificial kidney. The loss of oedema fluid by ultrafiltration of the blood is about 500 ml/h using a twin coil dialysator "Keradenta", or, resp., more than 1,200 ml/h using a Hollow Fibre Artificial Kidney "Dow Cordis" Mod. 5 or two HFAKs Mod. 4 in parallel. The method should be practised only in such cardiologic patients, in whom a drug-resistent hyperhydration including hypervolaemia is not a sign of a sure terminal state.

Edema↗
PubMed1999

Clinical importance of intraperitoneal pressure in peritoneal dialysis and measures to counteract its effect on net ultrafiltration.

Experiments in animals and in humans have shown that fluid loss from the peritoneal cavity to the body increases with large increments in the intraperitoneal hydrostatic pressure (IPP). We have demonstrated previously that much of this fluid loss occurs to the abdominal wall and is driven by the hydrostatic pressure gradient (i.p. pressure-skin pressure) that develops across the wall whenever therapeutic or pathologic volumes of fluid reside in the cavity. We hypothesized that eliminating the pressure difference across the wall by applying an equal and opposite pressure [abdominal counterpressure (ACP)] would decrease fluid movement into the wall and decrease fluid movement from the cavity. In addition, we hypothesized that net ultrafiltration or net fluid recovery would increase with ACP. To address these hypotheses, we dialyzed rats for 3 hours in the supine position at constant levels of IPP (4, 6, and 8 cmH2O) with isotonic or hypertonic dialysis solutions containing a protein marker of fluid movement. We measured total fluid loss, fluid marker concentration in the abdominal wall, and lymph flow. In separate animals, we repeated the experiments with ACP. Total fluid loss as determined by protein clearance and fluid marker deposition in the abdominal wall was decreased in all experiments. Lymph flow was unchanged by ACP. While ACP increased the net fluid recovery in isotonic dialysis, no change was observed in the hypertonic case. Analogous experiments were carried out in six dialysis patients with or without ACP during a 4-hour dialysis with 1.5% dextrose solution performed in the supine position at i.p. hydrostatic pressure of 4-6 cmH2O. No significant difference was noted in the measured net ultrafiltration between control and ACP studies. We conclude that the careful application of ACP does decrease fluid loss (particularly to the abdominal wall) during isotonic or hypertonic dialysis in the rat. However, ACP results in improved fluid recovery only with isotonic dialysis in rats and has no effect on the recovery of fluid during peritoneal dialysis in humans.

Abdomen↗
PubMed2000

Improved purification of water and waste-water with low-cost dead-end-ultrafiltration.

One aspect of the increasing contamination of water sources is sewage effluent. In some countries it is generally disinfected prior to discharge to protect downstream communities, which use the water for drinking and recreation. However, serious questions have been raised regarding the efficacy of conventional treatments to remove or destroy viruses, and regarding the generation of harmful byproducts by sewage chlorination. A safe and reliable solution is the use of ultrafiltration for the purification of wastewater, as the ultrafiltration membranes form an absolute barrier for bacteria and viruses including colloids and macromolecules. However, this application also demands the use of open channel module systems that can be cleaned with high efficiency with regard to scaling, fouling and especially biofouling. The flat membrane module systems using selected membranes and a special plant design can meet these and further requirements expected in this application, including easy handling, low energy consumption and optimised operation costs. Technical details of the module system, case studies and cost aspects are presented.

Cost-Benefit Analysis↗