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Adolfo Martinez Gustavo G U.D.E.F.A. SEDENA, Mexico, DEE, CREB, Technical University of Catalonia, Barcelona, - - 2005
The present work shows the development of a low-cost system to measure on-line blood urea concentration during dialysis procedures using optical sensor in the visible range. The objective in this project is obtaining the quantification of urea on-line during practices of the hemodialysis treatments. For which it has been considered ...
Goraca Anna - - 2004
OBJECTIVE: Magnocellular neuroendocrine cells of the supraoptic nucleus of the hypothalamus produce and release the hormones vasopressin and oxytocin in response to a variety of stimuli to regulate body water and salt as well as and parturition and lactation. The aim of the present study was to estimate oxytocin release ...
Di Filippo Salvatore - - 2004
BACKGROUND: An adequate estimation of urea distribution volume (V) in hemodialysis patients is useful to monitor protein nutrition. Direct dialysis quantification (DDQ) is the gold standard for determining V, but it is impractical for routine use because it requires equilibrated postdialysis plasma water urea concentration. The single pool variable volume ...
Tessitore Nicola - - 2004
BACKGROUND: Stenosis is the main cause of arteriovenous fistula (AVF) failure. It is unclear, however, if surveillance for stenosis enhances AVF function and longevity and if there is an ideal time for intervention. METHODS: In a 5-year randomized, controlled, open trial we compared blood flow surveillance and pre-emptive repair of ...
Jegger David - - 2004
Since the initiation of cardiac surgery using cardiopulmonary bypass, little progress has been made concerning the design of catheters for vascular access. However, in the last few years, research in this specialized field has established that catheter performance not only depends on size but also on the catheter's design. The ...
Stamatiadis D N - - 2004
AIM: Hemodialysis for patients bleeding or at risk for bleeding requires special modalities of treatment that are difficult to perform without potential side effects. A simple, safe and adequate method may be applied. METHODS: A modified way of extracorporeal circuit preparation, which focuses on minimizing the blood-air interface and negligible ...
Gotch Frank A - - 2004
BACKGROUND: Effective conductivity clearance (K(ecn)) has been reported to be a surrogate for effective urea clearance (K(eu)), where both are usually defined respectively as the dialyzer conductivity and urea clearances (K(cn), K(u)) corrected for access recirculation (R(ac)). However, many investigators have reported K(ecn)/K(eu) to be <1 and postulated anatomic distribution ...
Parakininkas Daiva - - 2004
OBJECTIVES: To compare the clearances of low molecular weight molecules using three modalities of continuous renal replacement therapy (CRRT) at the low blood flow rates typically used in pediatric patients. DESIGN: A controlled, in vitro laboratory study. SETTING: Research laboratory of a health sciences university. SUBJECTS: AN69 dialysis hemofilter. INTERVENTIONS: ...
Tylicki Leszek - - 2004
There are a variety of complications related to chronic hemodialysis treatment, including thrombosis in hemodialysis access leading to blood recirculation, and in turn to the deterioration in hemodialysis effectiveness. Given that ozone decreases blood viscosity, increases erythrocyte deformability, and inhibits coagulation, the periodic blood ozonation may be of benefit in ...
Sakamoto K - - 2004
Because the conductivity of blood changes remarkably during artificial dialysis, sometimes by more than 20%, changes in tissue admittance at low frequency are caused by changes not only in the extracellular fluid volume but also in blood conductivity. Therefore the changes in blood conductance due to artificial dialysis must be ...
Tessitore N - - 2004
The existing guidelines recommend arteriovenous fistulae (AVF) surveillance by access blood flow (Qa) measurement and the correction of hemodynamically significant stenoses to prolong access survival. Unfortunately, many studies supporting these recommendations are inadequate methodologically; therefore, both the optimal criteria for surveillance and the value of preventive stenosis repair in AVF ...
Osuga T - - 2004
A small degree of nonuniformity in dialysate flow in a hollow-fiber dialyzer was detected using proton magnetic resonance imaging (MRI). Since paramagnetic ions reduce the spin-lattice relaxation time of protons around them, MRI can detect Gd in water. An aqueous solution of a chelate compound of Gd was impulsively injected ...
Salis Ari I - - 2004
PURPOSE: Currently available 4-F and 5-F peripherally inserted central catheters (PICCs) were investigated to evaluate their possible application for contrast medium injection using power injectors. The study was performed using an in vitro model to demonstrate the feasibility of using PICCs for contrast-enhanced diagnostic studies. MATERIALS AND METHODS: An evaluation ...
Ash Stephen R - - 2004
The Allient is a dialysis system that combines various technologies to allow dialysis to be performed at sites outside of dialysis units (intensive care unit [ICU] or home) with ease and safety. A sorbent column regenerates dialysate, removing toxins and providing ultrapure dialysate from only 6 liters of tap water. ...
Eloot S - - 2004
Clearance of low (LMW) and middle molecular weight (MMW) solutes was investigated in vitro for different dialyzer configurations and mutual flow directions. Single pass tests were performed with two low flux Fresenius F6HPS hemodialyzers placed in series (12 tests) and in parallel (6 tests), and results were compared with those ...
Jaber Bertrand L - - 2004
Patients with end-stage renal disease (ESRD) have morbidity and mortality rates that are much higher than those found in the general population. The nonphysiologic nature of thrice-weekly hemodialysis may be partially responsible for the poor outcomes in this patient population. In response to the problems encountered with conventional hemodialysis schedules, ...
Dursun Belda - - 2004
In this study, we investigated whether a different priming process of the dialyzer could affect the dialysis adequacy in chronic hemodialysis (HD) patients. 20 HD patients (M/F:12/8) with a median age of 40 (20-74) were included in this study. All the patients were clinically stable and were on bicarbonate-based hemodialysis ...
Basile Carlo - - 2004
BACKGROUND: Clinical practice guidelines have supported vascular access surveillance programmes on the premise that the natural history of the vascular access will be altered by radiological or surgical interventions after vascular access dysfunction is detected. The primary objective of this study was to assess the actual risk of thrombosis of ...
Hellund Johan Castberg - - 2004
Our aim was to evaluate whether it is possible to visualize slow flow within a small catheter placed inside a living animal. We used a flow-sensitive, single-shot turbo spin-echo (SS-TSE) MRI sequence, developed in house, based on diffusion-weighted (DW) techniques. Four anesthetized pigs were used as models. A plastic catheter ...
Narsipur S S - - 2004
BACKGROUND: Fiber bundle volume (FBV) is an important determinant of dialyzer re-use efficiency. This measurement is performed after the dialyzer has been pressure cleaned and may underestimate the degree of clotted fibers a patient actually encounters while on dialysis. METHODS: Real-time online measure of FBV has been validated using an ...
Moreiras-Plaza M - - 2004
Central venous catheters are frequently used in leukapheresis to provide high flow rates. The most common locations are the subclavian or jugular vein, but insertion-related complications and inadequate flow are frequent problems. Experience using femoral venous access is limited, because this has been discouraged due to the high incidence of ...
Duranti E - - 2004
This study aimed at evaluating the feasibility of an acetate-free hemodialysis (AFHD) technique, comparing it with acetate-free biofiltration (AFB) and bicarbonate dialysis (BD). The assessment of the parameters concerned: electrolyte kinetics (Na+, K+), acid-base balance (HCO3-, pH), dialysis efficiency (Kt/V), serum beta2-microglobulin reduction ratio, nutritional status (normalized protein catabolic rate, ...
Leonard Edward F - - 2004
Dialysis between two flowing, miscible fluids without an intervening membrane enhances both the transport rate and biocompatibility. Unfortunately, it also presents serious challenges, including the loss of pressure as a driving force for volume transport, the need for sterile dialysate in greater quantity than in conventional dialysis, the possibility of ...
Marsala Martin - - 2004
To permit long-term measurement of time-dependent changes in levels of dialyzable drugs and transmitters in the spinal intrathecal (IT) space of the unanesthetized rat, we developed a dialysis catheter for chronic placement. This was accomplished by constructing a loop-flexible probe 9 cm in length from PE-5 polyethylene tubing and 4 ...
Twardowski Zbylut J - - 2004
Frequent dialyses are sometimes perceived as increasing the risk of blood access malfunction and decreased longevity. This review of the literature, however, indicates that the failure rates and overall fistula survival appear to be better with more frequent dialyses than with routine dialysis frequency, although the reasons for this phenomenon ...
Lopot F - - 2004
Measurement of vascular access flow (QVA) has been suggested as a method of choice for vascular access quality (VAQ) monitoring. Besides traditional duplex Doppler, a number of bedside methods based mostly on the Krivitski principle of QVA evaluation from recirculation at reversed needles (RX), have been developed. This work compares ...
Meloni Carlo - - 2004
BACKGROUND/AIMS: Hemofiltrate reinfusion (HFR) is characterized by the use of regenerated ultrafiltrate as replacement fluid. We set up a new technique, postdilution HFR (PD-HFR), aiming at increasing purification efficiency, treatment tolerance and at reducing inflammatory states. METHODS: We performed PD-HFR in 6 uremic patients during 1 year. Dialysis efficacy, dialyzer ...
Vilkomerson David - - 2004
A new ultrasound instrument has been developed, using vector Doppler and embedded machine intelligence, to enable measurement of access flow rates by non-specialists. Ultrasound measurement of access flow can be performed with the patient off the dialysis machine, avoiding the hemodynamic changes that may affect indicator-dilution methods. A research version ...
Falk A - - 2004
AIM: This is a retrospective study of reteplase efficacy for restoration of flow in occluded and poorly functioning hemodialysis catheters. PATIENTS AND METHODS: From May 1, 2001 to December 31, 2001, all hemodialysis patients seen at our university dialysis center with occluded or poorly functioning (< 200 ml/min blood flow) ...
Senécal Lynne - - 2004
Long-term catheters are widely used in some dialysis units. Because of higher dialysis dose targets, high flow catheters have been made available. We measured blood flow (Qb in ml/min) and recirculation rate (R%) in two types of tunneled dialysis catheters using ultrasound-dilution technology (Transonic). Thirty-seven catheters were evaluated (27 Opti-Flow, ...
Gradman Wayne S - - 2004
Steal phenomena associated with brachial bridge grafts for hemodialysis access may compromise blood flow to the forearm. This work is designed to investigate and compare, by means of a simple mathematical model, the potential of six surgical procedures to alleviate steal. A flow model based on an electrical analogue was ...
Depner Thomas A - - 2004
Inlet and outlet blood urea concentrations (Cin and Cout) can be used to directly measure dialyzer performance if simultaneous blood flow measurements (Qb) are available. Dialyzer clearance, for example, is the product of the urea extraction ratio [ER = (Cin - Cout)/Cin] and Qb. Urea concentrations are measured routinely in ...
Klingel Reinhard - - 2004
BACKGROUND: Treatment modalities of renal replacement therapy differ in their diffusive and convective mass transfer characteristics. It was the goal of this study to clarify whether an increase in convective mass transfer as performed with haemofiltration (HF) and haemodiafiltration (HDF) in comparison with high-flux haemodialysis (HD) is associated with an ...
Rysz Jacek - - 2004
BACKGROUND: Uraemia is accompanied by conditions favouring the rise of H2O2 activity in body fluids. This results from the increased release of H2O2 by polymorphonuclear leukocytes and decreased plasma glutathione peroxidase activity. The purpose of this study was to determine if patients on chronic haemodialysis (HD) exhale more H2O2 than ...
Diaz-Buxo Jose A - - 2004
The theoretical constructs of and limited clinical experiments with, continuous flow peritoneal dialysis (CFPD) are very promising. Specifically, removal of small molecular solutes has been shown to approximate that with quotidian hemodialysis. However progress has been slow because of the lack of an adequate peritoneal access device and the high ...
Lee W C R - - 2004
BACKGROUND AND OBJECTIVES: The removal of cytokines by standard hemofiltration is limited. Super high flux membranes may significantly improve removal even when used in dialysis mode. We sought to measure cytokine clearance using a large surface super high-flux membrane and a standard hemodialysis setting. SETTING: ICU laboratory of a tertiary ...
Potse Mark - - 2004
In the past few years, clinical trials with multielectrode "basket" catheters have provided unique recordings from the endocardium of intact in-situ human hearts. Analysis of these recordings is difficult because unipolar electrograms obtained from a basket catheter in the blood-filled cavity differ from those obtained by other mapping techniques such ...
Hyman Gary - - 2004
In occluded hemodialysis catheters, thrombolytic agents are used to dissolve fibrin clots, reestablish blood flow and allow the patient to continue with hemodialysis treatment. Prior to 2001, urokinase was the indicated fibrinolytic for hemodialysis catheter thrombolysis. However, when urokinase became unavailable in the United States, New Hanover Regional Medical Center ...
Molina P S C PS Inst. de Engenharia Biomedica, Univ. Fed. de Santa Catarina, Florianopolis, - - 2004
Dialysis access failure is the major cause of morbidity among patients undergoing hemodialysis. Reduced blood flow reveals access malfunction. This work discusses two methods based on directional continuous wave Doppler system to evaluate the access blood flow. By changing the dialysis blood pump flow rate, the variable flow Doppler method ...
Basile Carlo - - 2003
BACKGROUND: NKF K-DOQI clinical practice guidelines recommend a regular monitoring of vascular access (VA) through several methods, such as VA recirculation (AR). Assessment of AR is crucial to avoid inefficiency of hemodialysis (HD). A non-urea based method has been developed (ultrasound dilution Transonics Hemodialysis Monitor--USM) which is considered the gold ...
Huang Zhongping - - 2003
Recent research indicated that the dialysate flow distribution inside a hemodialyzer was not uniform ("channeling" of the dialysate flows). However, effect of the channeling on the solute clearance has not been directly and quantitatively examined. In this report, a novel experiment approach is presented to test the hypothesis that hollow ...
Gotch Frank A - - 2003
In vivo solute clearances can be estimated from dialyzer blood (Qb) and dialysate (Qd) flow rates and a solute- and dialyzer-specific overall permeability membrane area product (KoA). However, these calculations require knowledge of the flow rate of the effective solute distribution volume in the flowing bloodstream (Qe) in order to ...
Schneditz Daniel - - 2003
Low access blood flow is considered the most important cause of peripheral vascular access thrombosis, particularly with grafts. The measurement of access flow is time consuming, operator dependent, and may affect the efficiency of dialysis so that it cannot be done with every treatment. The measurement of recirculation, however, is ...
Weitzel William F - - 2003
Dialysis access monitoring may help decrease thrombosis-related morbidity. We investigated the effect of time elapsed since an access flow measurement on test accuracy of a novel flow monitoring method called variable flow (VF) Doppler. A retrospective review was conducted in 36 patients with prosthetic grafts for vascular access using access ...
Ronco C - - 2003
Continuous flow peritoneal dialysis (CFPD) is a therapy originally utilized in the sixties. It was then abandoned because of technical reasons, but, today, a new interest in this technique is emerging, because of new technical solutions and new hardware capabilities. CFPD is a peritoneal dialysis technique in which a certain ...
Passov Richard - - 2003
In late 2001, the directors of Pfizer asked that very question. And with good reason. After its 2000 merger with rival Warner-Lambert, the New York-based pharmaceutical giant found itself sitting on a net cash position of $8 billion, which seemed extraordinarily conservative for a company whose products generated $30 billion ...
Santoro Antonio - - 2003
The traditional control of the dialysis session comes about by means of an open-loop system. At the beginning of the session some parameters are set, such as the kind of dialyzer, the blood flow, the ultrafiltration rate, the dialysate conductivity and the dialysate temperature. Generally speaking, these parameters are not ...
Farjo Linda - - 2003
A discussion of complications related to the use of central venous catheters (CVCs), literature review, and a retrospective study were performed to see if blood collection from peripherally inserted central catheters (PICCs) in the treatment of oncology patients was a feasible option. The results were used to evaluate and update ...
Hoeben Heidi - - 2003
BACKGROUND/AIMS: Vascular access thrombosis is one of the most morbid problems encountered by hemodialysis patients. Surveillance protocols utilizing venous pressure (Vp) and vascular access blood flow (VABF) measurements have been employed to preserve vascular access. We undertook a study to evaluate combined dynamic Vp and VABF measurements in the identification ...
Pasko Deborah A - - 2003
In critically ill children weighing <10 kg, it is necessary to use blood as a priming solution for the extracorporeal continuous renal replacement therapy (CRRT) circuit before initiating CRRT to prevent hemodilution and maintain adequate oxygenation. However, blood bank blood usually contains supra-physiological electrolyte concentrations and a non-physiological acid-base balance ...
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