PubMed Health⌕ Search

Biomedical subjects

J Y De Vos

Publications and source records attributed to J Y De Vos.

At least 19 recordsLinked to original sources
PubMed2004

Diffusive clearance of small and middle-sized molecules in combined dialyzer flow configurations.

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 for one single dialyzer (2 tests). Either high concentrated (45mS/cm) bicarbonate dialysis fluid (surrogate LMW) or trisodiumphosphate (surrogate MMW) concentration (31mS/cm) was used as blood substitution fluid. Standard blood and dialysate flows of 250 and 500ml/min, respectively, were prescribed. Clearance was derived from conductivity measurements in blood and dialysate compartment, correcting for the overall ultrafiltration rate of 0.1-0.5l/h. In a single dialyzer, changing the counter current flow to co-current deteriorates diffusive clearance by 14% (LMW) and 18% (MMW). Compared to one single dialyzer using counter current flow, clearance increases by 3 to 8% (LMW) and by 15 to 18% (MMW) using two dialyzers in parallel and in series, respectively. As a consequence, the benefit by using a second dialyzer is more prominent for larger molecules. Moreover, pressure profiles drawn for the different configurations show the impact of limited convection on diffusive clearance.

Diffusion↗
PubMed2002

Anticoagulation therapy in acute renal failure extracorporeal treated patients.

In extracorporeal techniques, as used for Acute Renal Failure (ARF) treatments, blood is constantly exposed to foreign surfaces. These foreign surfaces include the catheter(s), blood tubings, the dialyser membrane and all artificial materials used for such techniques in general. Blood begins to clot as soon as it strikes a foreign surface. The foreign surface initiates the clotting process. The extracorporeal circuit is prone to clotting during acute treatments unless some form of anticoagulation is employed. On the other hand, this specific group of patients is often at increased risk of bleeding (cfr. Post-operative patients and post-renal-transplant patients, patients with Multiple Organ Failure (MOF) often including liver disturbances). It should be kept in mind that patients with renal failure have a defect in platelet function resulting in altered platelet-vessel wall interaction. Over time, as the extracorporeal treatment progresses, the platelets become more adhesive or sticky. The blood becomes more likely to clot. Performing effective therapy with low bleeding risk in ARF patients is a challenge requiring knowledge, skills and experience.

Acute Kidney Injury↗
PubMed1997

Blood trauma in plastic haemodialysis cannulae.

To investigate the haemolysis in haemodialysis cannulae, an in-vitro set up is built, using a unipuncture dialysis system. This system is connected to a bag with fresh calf's blood, by the cannula under test, mounted in a large bloodline (5 mm diameter). The blood characteristics are kept constant by means of a bicarbonate dialysate in the dialyser. During a 6 h period, haematological parameters are regularly samples. Flow through the cannulae is recorded, which is about 500 mL/min. Four different cannulae are tested and compared to the results obtained without any cannula in the circuit. In all cases a linear increase in plasma free haemoglobin levels is found after 6 h. The cannulae can be ranked from 8F catheter over 13G, 14G to 16G cannula, the latter producing the highest degree of haemolysis. When using plastic cannulae at high blood flows, their haemolytic effect may not be neglected.

Animals↗
PubMed1994

Fibrin sheet covering subclavian or femoral dialysis catheters.

The existence of a sheet around a single lumen dialysis catheter tip, which provokes a valve mechanism, is proved by the observation that several times during the replacement procedure of a dialysis catheter, a sheet surrounding the surface of the catheter is removed with the dialysis catheter. This sheet is grey, approximately 1 mm thick and 30 mm long and consists of fibrin and thrombocytes. Bacteriological examinations were always negative. The existence of the sheet in vivo is demonstrated by digitalized angiography during the removal procedure for single lumen dialysis catheters. Rarely, only the sheet is removed with the catheter. It all other instances, the sheet is stripped off and remains in the subcutaneous tunnel or in the vascular bed without causing much clinical discomfort in most patients. Occasionally an episode of cough, dyspnea, hypotension, retrosternal oppression or hemoptae after removing the single lumen dialysis catheter, suggest pulmonary embolism or lung infarction.

Catheters, Indwelling↗
PubMed1994

Severe electrolyte disturbances in lethal subclavian catheter dialysis.

Syncope, irreversible shock, and respiratory and circulatory arrest developed in a 54-year-old diabetic man chronically dialyzed with a subclavian catheter (SC) minutes after the end of a dialysis session. Resuscitation attempts remained unsuccessful. During the resuscitation attempt, a blood analysis showed severe hyponatremia, acidosis, and hypochloremia. Respiratory and cardiac arrest developed during dialysis in a 64-year-old woman on chronic SC dialysis. Resuscitation was unsuccessful; chloremia levels were 79 mEq/L, and calcemia levels were 20 mg%. Both patients were dialyzed with a standard dialysate solution. The reasons for the electrolyte disturbances could not be explained technically. The autopsy showed myocardial perforation by the SC and accumulation in the pericardium of the fluids administered during the resuscitation attempt (e.g., glucose 5%, bicarbonate, Ca gluconate, human albumines), thus explaining the erroneous electrolyte results. The reason for the perforation was a too-rigid central femoral vein catheter, erroneously labeled a subclavian catheter by the supplying firm. Because of a syndrome of progressive vena subclavia and vena cava sclerosis with insufficient arterial phase flow and venous-phase bleeding around the puncture site during single-needle dialysis, the original SC had to be replaced by a longer one with the tip located in the atrium (this SC was actually a femoral catheter). Analysis of the fluid aspirated through the SC can determine the diagnosis in sudden death of SC dialysis patients.

Catheterization, Central Venous↗
PubMedDate not supplied

Polyunsaturated fatty acids of the n-3 class in chronic dialysis.

N-3 PUFAs are believed to 1) reduce serum lipids, 2) modify the complement activating system, 3) increase red blood cell elasticity, and 4) decrease thrombotic events. These four parameters were investigated in 19 chronic stabilized dialysis patients assessed by 1) the control of the serum lipids, 2) the degree of leukopenia 10 minutes after the start of dialysis, 3) the degree of red cell fragmentation (RCF) during dialysis, and 4) the reusability of the dialyzer. The patients were their own controls during four periods: 1) no PUFAs for longer than 6 months, 2) 4 x 425 mg of PUFAs/day for 6 weeks, 3) 6 x 425 mg PUFAs/day for 6 weeks, and 4) no PUFAs during at least 6 weeks. Previous diets and medications remained unchanged. It was concluded that there was no significant effect on serum lipids in the given dosages, and no effect on the degree of leukopenia, red blood cell elasticity or bleeding, and/or antithrombotic activity. No change was seen in insulinemia, fibrinogenemia, or arterial pressure. No serious side effects were noted other than a "fishy aftertaste."

Adult↗
PubMedDate not supplied

Heparinisation in chronic haemodialysis treatment: bolus injection or continuous homogeneous infusion?

After several incidents where patients either bled after dialysis or suffered severe anaphylactic reactions caused by intravenous heparin injections, we decided to administer heparin as a continuous homogeneous intravenous infusion. This had been usual practice in our unit in the past. Following the shocking experience of the death of a patient due to an anaphylactic reaction during his first dialysis, we wanted to warn colleagues for the potential dangers of administering intravenous heparin as a bolus injection.

Aged↗
PubMedDate not supplied

Quality monitoring of care: ask the patient.

In 1998 and 1999, we organised a questionnaire to be filled out by chronic haemodialysis patients. The first part dealt with general information data on the specific patient and the second part dealt with quality assessment data given as experienced by the individual patient. This second part included a ranking of preference by the patients and aspects patients wanted to see improved in the future. As we implemented the EDTNA/ERCA Clinical Standards and Core Curriculum, the monitoring tool, as described in this paper, was developed in order to monitor the effect of implementation. As a result of this two-year monitoring process of quality of care, we can follow up the care provided by our multidisciplinary team. It has proven a very useful tool to find out what is to stay as it is and what is to be improved. Simply closing the loop!

Ambulatory Care Facilities↗
PubMedDate not supplied

European practice database: results from Greece.

The survey (EPD) took place during December 2002-January 2003 and presents renal care in Greece. A questionnaire, structured at European level and translated into Greek, was sent to all dialysis centres (114) by post. The questionnaire was returned from 74 centres (64.9%). Some important results were: low use of peritoneal dialysis (13.3%), half of PD patients over 65 years old, one ninth of patients on transplantation waiting list, isolation for HBV positive patients (less for HCV and HIV), high use of AV fistulae (71.2%), maintenance and repair of dialysis machines by company technicians, absence of renal dieticians and social workers (but availability from hospital employees) one nurse every 5.54 patients (3.72 if nurse assistants are included), disinfection between shifts carried out chemically (hot or cold) and puncturing of vascular access performed mainly by nurses and nurse assistants. Data can be used to pressurise government for more scientists in the multidisciplinary team to be hired in hospitals, develop further research topics and to develop continuous education programmes.

Age Factors↗
PubMedDate not supplied

The European practice database (EPD): results of the study in thte North-East of Italy.

The survey, realized in 2002-03 in the North-East of Italy, describes renal care in dialysis services. A questionnaire, structured at European level, was sent to all dialysis centres by mail. The questionnaire was returned from 21 centres (61.8%) and related satellite units. Results show nonhomogeneity in renal care. Some important results were: low use of peritoneal dialysis (18%), compared to the rest of Europe, elevated presence of older people on haemodialysis, reduced percentage of patients on transplantation waiting list, diffused use of isolation for HCV positive patients, high use of AV fistulae (84%), low employment of renal technicians, absence of renal dieticians and social workers and nurses performing prevalently direct care. Data can be used for different goals: benchmarking activities, selection of deeper research topics and development of more oriented continuous education activities.

Adolescent↗
PubMedDate not supplied

The Research Board of EDTNA/ERCA: research activities and deliverables.

The Research Board (RB) of EDTNA/ERCA was formed ten years ago to provide opportunities for our members to participate in collaborative research projects at a European level. It provides educational support in research methodology via workshops at conference and in articles published in the Journal. The group has completed a total of seven collaborative research projects in diverse areas of renal care and has recently developed an ambitious new project, the European Practice Database (EPD). The EPD project aims to capture the current practice of renal care professionals in European centres on a three-year repeating cycle. The results of projects are presented at conference and at international scientific meetings by invitation and abstract submission. Recommendations, guidelines or educational material are produced collaboratively with the renal multi-disciplinary community.

Cooperative Behavior↗