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At least 19 recordsLinked to original sources
PubMed2001

Balanced ultrafiltration, modified ultrafiltration, and balanced ultrafiltration with modified ultrafiltration in pediatric cardiopulmonary bypass.

This study evaluates the effect of balanced ultrafiltration, modified ultrafiltration, and balanced ultrafiltration with modified ultrafiltration on inflammatory mediators in children's open-heart surgery. Eighty children with congenital heart disease were randomly divided into four groups: control group (C group); balanced ultrafiltration group (BUF group); modified ultrafiltration group (MUF group); and balanced ultrafiltration with modified ultrafiltration group (B+M group). Clinical data of these groups were similar. Tumor necrosis factor (TNF), interleukin-8(IL-8), and E-selectin were measured at the beginning of cardiopulmonary bypass (CPB), 30 min later, at the cessation of CPB, at the cessation of MUF (MUF group and B+M group), and 2 hours postoperatively. During CPB, the concentrations of TNF, IL-8, and E-selectin increased significantly in C and MUF groups and did not change significantly in BUF and B+M groups. In the period of MUF, TNF and IL-8 increased; whereas, E-selectin did not change. The study shows that ultrafiltration can filter out the inflammatory mediators, but only BUF can decrease the concentrations of them. Moreover, MUF only can concentrate blood. Combining both techniques has both effects, but the effect of BUF was offset by MUF.

Cardiopulmonary Bypass↗
PubMed1998

The hemodynamic effect of different ultrafiltration rates in patients with cardiac failure and patients without cardiac failure: comparison between isolated ultrafiltration and ultrafiltration with dialysis.

OBJECTIVE: The increasing number of dialysis patients with cardiovascular diseases will lead to an increase in the incidence of intradialytic hypotension. Intradialytic hypotension is determined by changes in plasma volume, changes in vascular reactivity and structural cardiovascular changes. In this study the effect of two different ultrafiltration rates (UF-rate), i. e. 500 and 1000 ml/h, on plasma volume, extracellular volume and arterial blood pressure was studied during different treatments of 2 hours combined ultrafiltration + hemodialysis (UF+HD) and 2 hours isolated ultrafiltration (i-UF). PATIENTS AND METHODS: 15 Patients, 8 patients with cardiac failure, CFpts (NYHA classification III and IV) and 7 patients without cardiac failure (NCFpts) were investigated during a standardized dialysis treatment. RESULTS: The decrease in plasma volume and decrease in extracellular volume was comparable both between i-UF and UF+HD and comparable between CFpts and NCFpts and was only dependent on the UF-rate. i-UF resulted in minor blood pressure changes in both CFpts and NCFpts. In CFpts UF+HD resulted in a significant decrease in systolic blood pressure (SBP) at both UF-rates while in NCFpts SBP decreased significantly only at the higher UF-rate during UF-HD. Although there were no significant differences in hemodynamic stability during the different treatment modalities between CFpts and NCFpts, the decrease in SBP in CFpts at the higher UF-rate during UF+HD was much more pronounced. CONCLUSION: From this clinical study we conclude that differences in hemodynamic stability between i-UF and UF+HD and between CFpts and NCFpts are not related to differences in plasma volume preservation. Other factors like different changes in vascular reactivity and in CFpts structural cardiovascular changes might be responsible for the observed differences.

Aged↗
PubMed1998

Modified ultrafiltration versus conventional ultrafiltration: a randomized prospective study in neonatal piglets.

UNLABELLED: Cardiopulmonary bypass in neonates generates large increases in inflammatory mediators, causing edema formation that may lead to multiple organ dysfunction. Clinical strategies aimed at removing inflammatory mediators, reducing edema formation, and improving organ function include conventional and modified ultrafiltration. OBJECTIVE: This study examines the effectiveness of conventional and modified ultrafiltration in preventing weight gain, myocardial edema formation, and left ventricular dysfunction in neonatal piglets undergoing cardiopulmonary bypass. METHODS: In this randomized prospective study, 18 1-week-old piglets were supported with cardiopulmonary bypass at 100 ml kg(-1) x min(-1), cooled to 25 degrees C, exposed to 75 minutes of cardioplegic arrest, rewarmed to 37 degrees C, and weaned from bypass. Left ventricular myocardial contractility was assessed by the preload-recruitable stroke work method, with the use of a sonomicrometric two-dimensional cylindrical model, before bypass and at 10, 60, and 120 minutes after separation from bypass. RESULTS: Total body weight gain was significantly less in the modified ultrafiltration group than in either the conventional ultrafiltration group or the control group (no filtration). Myocardial wet/dry ratios were also improved with modified ultrafiltration, but not with conventional ultrafiltration, when compared with no filtration (control group). Hemodynamically, modified ultrafiltration was superior to conventional ultrafiltration and no filtration (control) in raising the mean arterial pressure and increasing the left ventricular preload-recruitable stroke work after bypass. CONCLUSION: Modified ultrafiltration is superior to conventional ultrafiltration and no filtration in reducing the total body weight gain, lessening myocardial edema, raising mean arterial pressure, and improving left ventricular contractility in neonatal piglets undergoing cardiopulmonary bypass and cardioplegic arrest.

Animals↗
PubMed1983

Ultrafiltrable calcium and magnesium in ultrafiltrates of serum prepared with the Amicon MPS-1 system.

We evaluated the Amicon micropartition system (MPS-1) for preparing ultrafiltrates of serum for use in evaluating ultrafiltrable Ca and Mg. We found no adsorption of either to the filter and 99.6% retention of serum proteins on the membrane. Ultrafiltrate volumes recovered (100-450 microL) varied with centrifugation time (10-30 min) and temperature. Centrifugation time did not affect the measured concentration of ultrafiltrable calcium and magnesium, and pH change in the 1-mL serum specimen during a 30-min centrifugation at room temperature was negligible. There was an inverse relationship between temperature and ultrafiltrable Ca and Mg concentrations. The precision (CV) between filters ranged from 1.2 to 5.1% for ultrafiltrable Ca and 1.5 to 2.7% for ultrafiltrable Mg. The correlation between ultrafiltrable Ca (y) and ionized Ca (x) in samples from 115 patients with calcium-related metabolic disorders was good (y = 1.04x + 0.18; r = 0.9128). We find the MPS-1 to be a simple and convenient tool for the rapid production of serum ultrafiltrates.

Adult↗
PubMed2002

[Comparative study of pulmonary function after conventional ultrafiltration or modified ultrafiltration during cardiac surgery of infants].

OBJECTIVE: To compare the effects of conventional ultrafiltration and modified ultrafiltration in protecting patients' pulmonary function during cardiopulmonary bypass. METHODS: Thirty infants patients (less than 7 kg) were divided into two groups: conventional ultrafiltration group (CUF, n = 15) and modified ultrafiltration group (MUF, n = 15). The volume of ultrafiltration, transfusion, hematocrit (HCT) before and after ultrafiltration, patients' respiration function (respiration index, A-aDO2, airway pressure), the time of mechanical ventilation and ICU in the two groups were respectively monitored. RESULTS: The transfusion in MUF group was significantly less than in CUF group (P < 0.01), and the volume of ultrafiltration in MUF group was significantly more than in CUF group (P < 0.01). The time of mechanical ventilation and ICU staying in MUF group were significantly shorter in MUF group than that in CUF group (P < 0.05). At 12 and 24 hours after operations, the A-aDO2 in MUF group was lower than that in CUF group (P < 0.05), and the respiratory index in MUF group was higher than that in CUF group (P < 0.05). CONCLUSION: The modified ultrafiltration can effectively improve pulmonary function after operations for low weight infants.

Cardiopulmonary Bypass↗
PubMed1993

Ultrafiltration and modified ultrafiltration in pediatric open heart operations.

The capillary leak associated with cardiopulmonary bypass results in an increase in content of water in the tissues measurable by an increase in total body water after cardiac operation. Following work by Magilligan in the 1970s, ultrafiltration was introduced during bypass as a means of hemoconcentrating patients and potentially removing water from the tissues. Conventional methods proved inconsistent; thus, we modified the technique to ultrafilter the patients immediately after cessation of bypass. Modified ultrafiltration takes 10 minutes and results in an elevation of the on-bypass hematocrit to about 35% or 40%. In pilot studies comparing bypass in absence of ultrafiltration with conventional ultrafiltration and modified ultrafiltration, only the modified technique was seen reliably to reduce the elevation in total body water to only 4%, within a narrow range. Subsequent prospective studies confirmed the reduction in accumulation of total body water and also demonstrated a reduction in blood loss and in requirements for blood transfusion. Systolic blood pressure was observed to increase uniformly in all patients undergoing modified ultrafiltration. This effect was investigated and found to be associated with a marked increase in cardiac index, no change in systemic vascular resistance, a decrease in heart rate, and a marked decrease in pulmonary vascular resistance. Recently, we have demonstrated an increase in contractility and a decrease in myocardial wall volume. The modified technique of ultrafiltration has been employed successfully in more than 400 patients in our institution, and represents an excellent option for perioperative management of both accumulation of fluid in the tissues and hemodynamics after hypothermic bypass.

Adolescent↗
PubMed2001

Hemodynamic response to fluid withdrawal in overhydrated patients treated with intermittent ultrafiltration and slow continuous ultrafiltration: role of blood volume monitoring.

Fluid overload may occur in patients with congestive heart failure, especially when there is associated acute renal failure. When the pharmacological approach is not sufficient to maintain the patient's fluid balance, extracorporeal therapies must be instituted. However, since the ultrafiltration rate may be faster than fluid refilling from the interstitial space, remarkable changes in the circulating blood volume may occur. This may finally result in further worsening of peripheral perfusion due to a significant drop in cardiac output. In order to prevent a fall in the circulating blood volume, slow continuous ultrafiltration (SCUF) should be employed instead of acute intermittent ultrafiltration (UF). To further improve the tolerance to extracorporeal ultrafiltration, the session can be driven by the relative blood volume change monitored on-line with adequate sensors and devices. We utilized one of these systems (Crit-Line, Hemametrics, USA) to compare the relative changes in blood volume during UF and SCUF in 22 patients with fluid overload. Variations in blood pressure were significantly greater with UF than with SCUF even in the presence of similar levels of fluid removal. The variations in blood pressure were paralleled by variations in blood volume, which were greater with UF than with SCUF. In conclusion, extracorporeal ultrafiltration can be used to control the fluid balance in congestive heart failure, but it is advisable to prescribe low ultrafiltration rates over an extended period of time. The use of on-line blood volume monitors can be of further help in improving tolerance and the hemodynamic response.

Acute Kidney Injury↗
PubMed2003

Combination of balanced ultrafiltration with modified ultrafiltration attenuates pulmonary injury in patients undergoing open heart surgery.

OBJECTIVE: To explore the effects of ultrafiltration technique in preventing and relieving pulmonary injury in children undergoing open heart surgery and cardiopulmonary bypass (CPB). METHODS: Thirty cases with congenital heart defects were divided into a control group and an experimental group. In the control group, conventional cardiopulmonary bypass was used without ultrafiltration; while in the experimental group, cardiopulmonary bypass with balanced ultrafiltration and modified ultrafiltration were used. Pulmonary static compliance (Cstat), airway resistance (Raw), alveolar-arterial oxygen difference (A-a DO2), hematocrit (HCT), serum albumin (Alb), interleukin-6 (IL-6), endothelia-1 (ET-1) and thromboxane (TXB2) were measured. RESULTS: The pulmonary function was improved, HCT and serum albumin concentrations were increased, and some harmful medium-size solutes were decreased in the experimental groups compared with the control group. CONCLUSIONS: Combination of balanced ultrafiltration with modified ultrafiltration can effectively concentrate blood, exclude harmful inflammatory mediators, and attenuate lung edema and inflammatory responsive pulmonary injury.

Cardiac Surgical Procedures↗
PubMedDate not supplied

Maximum ultrafiltration rate in continuous arteriovenous hemofiltration does not occur at the lowest level of the ultrafiltrate collection chamber.

A common assumption is that increasing transmembrane pressure by lowering the ultrafiltrate receptacle and the accompanying fluid column should always result in increasing ultrafiltration in continuous arteriovenous hemofiltration (CAVH) systems. To test this assumption, CAVH circuits were operated in vitro with use of a recirculating apparatus with an adjustable elevated reservoir. Hydraulic operational characteristics were studied in a variety of CAVH circuits, lowering the height of the ultrafiltrate column stepwise until it was at the lowest height possible. The results for most experiments performed reveal that ultrafiltration rate (UFR) reaches a peak and then declines as the collection receptacle is lowered further. There is also a decline in pre-filter blood flow preceding the peak in UFR. At lower blood flow, UFR decreases for the same transmembrane pressure (TMP). Therefore, as ultrafiltrate pressure is decreased, the effect of increased TMP on UFR is opposed by the effect of decreased blood flow, which decreases UFR. The implication of this in clinical medicine is that one may need to empirically test UFR in a CAVH system in positions other than the very lowest position.

Blood Flow Velocity↗
PubMed1976

A new device for ultrafiltration. The ultrafiltrability of calcium and inorganic phosphate in human serum.

The various problems concerning the ultrafiltration of blood serum are outlined, and a novel ultrafiltration device, which overcomes all these problems is presented. Its main advantages are the following: (1) The deposition of protein on the filter is prevented by producing a flow across the filter surface. (2) The pCO2 remains constant, since the fluid is not in contact with a gas space. (3) The minimum serum volume is only 0.4 ml (4) Six samples can be processed simultaneously. (5) All commercially available filter types can be used. The machine, tested by measuring the ultrafiltrability of calcium, inorganic phosphate, sodium and chloride in human serum, proved to be a reliable laboratory tool. The precision of the determinations were comparable to respective serum analyses. The ultrafiltrabilities obtained, without correction for water content of serum, were 55.6 +/- 2.9% for calcium, 88.3 +/- 5.0% for inorganic phosphate, 95 +/- 1.7% for sodium, and 103 +/- 0.7% for chloride (means +/- S.D.).

Adult↗
PubMed1980

Controlled ultrafiltration during single-pass dialysis with the RP-6 dialyzer and evaluation of its time-dependent ultrafiltration index.

A simple and inexpensive method is described for controlling ultrafiltration when using the high flux RP-6 dialyzer. When th RP-6 is operated in the co-current mode and with single-pass dialysate delivery, (PBo-PDo) can be used to accurately and safely control ultrafiltration. Combined results from ten dialyses indicate there is a pressure-dependent concentration polarization which affects ultra-filtration as reported previously, and in addition, a time-dependent effect indicating a more complex dialyzer/blood interaction. The ultrafiltration index decreases linearly with time. The ultrafiltration can be adequately predicted by (Formula: see text).

Blood Flow Velocity↗
PubMed1988

Blood volume change during isolated ultrafiltration and combined ultrafiltration-dialysis.

Despite extensive study of the difference in the cardiovascular response to ultrafiltration in isolation and during haemodialysis, there is still disagreement in the literature as to whether or not there is a difference in the efficiency of plasma refilling between the two procedures. We believe that this results both from the use of inadequate techniques to measure change in blood volume and shortcomings in experimental design. We have employed novel methods in ten patients to study plasma refilling during isolated ultrafiltration and dialytic ultrafiltration. Measurement of blood pressure and heart rate confirmed the inferior cardiovascular tolerance to haemodialysis observed by others. However, no difference in the rate of plasma refilling could be demonstrated. Our observations suggest that the superior tolerance to isolated ultrafiltration is not explained by differences in vascular refilling.

Adult↗
PubMed1987

Plasma volume changes induced by sequential ultrafiltration-hemodialysis and sequential hemodialysis-ultrafiltration.

Isolated ultrafiltration (UF) has been shown to preserve plasma volume (PV) by means of a high plasma refilling rate, mediated by a rapid rise in oncotic pressure. This mechanism contributes to the good tolerance of sequential ultrafiltration-hemodialysis (SUH). This study compared PV changes induced by SUH and sequential hemodialysis-ultrafiltration (SHU). Seven dialysis patients underwent two sets of SUH and SHU, in which 2 h of UF (approximately equal to 3L) respectively preceded or followed 2 h of no-weight-change hemodialysis (ISO HD). VEM (volume of extravascular mobilization), VEM/VUF (percent of plasma refilling rate) and delta PV were calculated by mathematical formulas. Results showed: 1) a high VEM/VUF during the UF period, either before or after ISO HD: 80 and 77% respectively; 2) a significant increase in PV during ISO HD after UF, compared to ISO HD before UF: + 229 ml and + 43 ml, P less than 0.05; 3) VEM/VUF significantly higher during SUH than during SHU: 87 and 80%, P less than 0.01. In conclusion, the decrease in PV was lower in SUH than in SHU (11 vs. 19%, P less than 0.001) because the plasma refilling persisted through the ISO HD period.

Combined Modality Therapy↗
PubMed1973

Dynamics of glomerular ultrafiltration in the rat. IV. Determination of the ultrafiltration coefficient.

Pressures and flow rates were measured in accessible surface glomeruli of mutant Wistar rats under conditions deliberately designed to prevent achievement of filtration pressure equilibrium, that is, the equalization of transcapillary hydrostatic and oncotic pressures by the efferent end of the glomerulus as typically observed in the normal hydropenic rat. Disequilibrium was obtained at elevated levels of glomerular plasma flow (GPF) brought about by acute expansion of plasma volume with a volume of rat plasma equal to 5% of body weight. Glomerular hydrostatic and oncotic pressures measured at high GPF were used to calculate the ultrafiltration coefficient, K(f), the product of effective hydraulic permeability and surface area. GPF was then either lowered (by aortic constriction) or raised (by carotid occlusion) in order to examine the dependence of K(f) on GPF. The value of K(f) per glomerulus, 0.08 nl/(s.mm Hg), was found not to vary over an approximately twofold range of GPF. This finding, taken together with data from previous studies from this laboratory, leads us to conclude that plasma-flow dependence of glomerular filtration rate (GFR) results primarily from flow-induced changes in mean ultrafiltration pressure, rather than large changes in K(f).

Animals↗
PubMed2004

Removal of phenolic compounds in pomegranate juices using ultrafiltration and laccase-ultrafiltration combinations.

Phenolic compounds of fruit juices are responsible for haze and sediment formation as well as for color, bitterness and astringency. The influence of ultrafiltration (UF) and laccase-UF combination was investigated on phenolic contents of pomegranate juices and on filtration output. Laccase-treated and then ultrafiltered pomegranate juices have shown a rapid increase in their color, when compared to only ultrafiltered (control) samples. Kinetic parameters of laccase were also determined. During the oxidation period, the changes occurring in pomegranate juices were estimated from phenolic contents, color and anthocyanin measurements. Results have shown that laccase oxidation produced a significant decrease in phenolic content of pomegranate juices while juice color the increased. However, in recent literatures, the possibility to remove polyphenols in apple juices was reported. We decided in this study that laccase treatment can not be applied due to the loss of natural red color and unwanted dark brownish color formation in pomegranate juice.

Antioxidants↗