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Biomedical subjects

C Ronco

Publications and source records attributed to C Ronco.

At least 181 records · Page 10Linked to original sources
PubMed1998

Continuous plasma filtration coupled with sorbents.

An in vitro system composed of a plasma separation membrane coupled with natural (charcoal) or synthetic (Amberlite, Amberchrome) types of sorbents was evaluated for the simultaneous removal of proinflammatory cytokines (TNF-alpha, IL-1 beta and IL-8) and cytokine antagonists [interleukin (IL)-1 receptor antagonist (IL-1Ra), soluble tumor necrosis factor-alpha (TNF-alpha) receptor I and II (sTNFR I and II)] in whole blood spiked with bacterial lipopolysaccharide (LPS). These studies showed that plasma filtration rather than ultrafiltration significantly increased the clearance of all cytokines, particularly TNF-alpha, and the synthetic (Amberlite-type of resin) but not natural (uncoated charcoal) membrane could extensively absorb almost 100% of plasma filtered IL-Ra, IL-1 beta and IL-8, but only 40% of TNF-alpha. Other synthetic (Amberchrome) membranes could also effectively (80%) remove TNF-alpha. In the complex scenario of sepsis, the simultaneous removal of excess proinflammatory and/or immunomodulatory mediators may play a role in reducing the hemodynamic alterations, thus resulting in enhanced patient survival. Whether this occurs in the human setting awaits the results of an ongoing clinical investigation.

Adsorption↗
PubMed1998

Quo vadis CRRT?

Explore the source record for details and available documents.

Acute Kidney Injury↗
PubMed1998

Continuous renal replacement therapy: continuous blood purification in the intensive care unit.

Severe acute renal failure (SARF) occurs when renal dysfunction is such that haemodialysis or haemofiltration becomes necessary to maintain homeostasis. SARF is increasingly seen in association with multiorgan failure and has become a predominantly Intensive Care Unit disorder. Because of this change in epidemiology, the treatment of SARF has evolved from being exclusively nephrologist and intermittent haemodialysis-based to being mostly intensivist and continuous haemofiltration-based, particularly in European countries with a strong ICU tradition and in Australia. Continuous renal replacement therapy (CRRT) has several advantages in critically ill patients, including greater flexibility, excellent haemodynamic tolerance, outstanding fluid balance control, excellent control of uraemia, prevention of cerebral oedema, ability to provide full and aggressive nutrition, and a possible anti-inflammatory effect. The blood purification effect of CRRT may, in fact, go beyond the simple control of uraemia. Several animal studies have now shown that CRRT attenuates the haemodynamic consequences of bacteraemia or endotoxaemia. Such studies have also shown that increasing the intensity of fluid exchange may offer further beneficial effects in the setting of sepsis. In the light of these findings, CRRT is moving into the area of adjuvant treatment of sepsis, and pilot randomized controlled trials are being conducted to test the hypothesis that CRRT, either in standard or high fluid exchange volumes, attenuates the inflammatory effects of sepsis in humans. In the future, the use of CRRT may extend beyond its initial scope into the area of adjuvant management of sepsis and continuous blood purification may become part of a complex multifaceted approach to multiorgan dysfunction.

Acute Kidney Injury↗
PubMed1997

Out of hospital outcome and quality of life in survivors of combined acute multiple organ and renal failure treated with continuous venovenous hemofiltration/hemodiafiltration.

OBJECTIVE: To study the out-of-hospital quality of life and long-term survival of critically ill patients with combined multiple organ failure and acute renal failure treated with continuous renal replacement therapy (CRRT). DESIGN: Study based on responses to postal questionnaire and clinical information obtained during treatment in the intensive care unit (ICU). SETTING: ICUs of two tertiary institutions. PATIENTS: 85 survivors from a pool of 250 patients with combined acute multiple organ and renal failure who were treated with CRRT. METHOD AND RESULTS: Anonymous postal questionnaire based on an activity index, mental function index, and a simplified version of the Nottingham Health Profile. Of the 250 patients, 85 (34%) survived to be discharged from hospital: 57 males (67%) and 28 females (33%), mean age 56.9 years (range 13.4-81). Mean duration of ICU stay was 10.9 days (range 2-52), mean admission Acute Physiology and Chronic Health Evaluation II score was 24.2 (range 15-41), and mean duration of CRRT was 6.2 days (range 1-34). Mean follow-up time was 2.5 years (range 0.1-5.3). Thirty-three of the 85 patients (38.8%) did not reply to the questionnaire; 35 patients (41.7%) were alive at the time of response and 17 (20%) were deceased. Of the 35 responders, 68.5% were satisfied with their present state of health, despite 60.6% stating that their mobility had been affected, with 41.9% being unable to walk more than 200 metres. Most (94.5%) survivors, however, felt that their treatment had been worthwhile, and 91.2% said that they would undergo the same treatment again if necessary. The approximate cost for each year of survival was U.S. $ 50000. CONCLUSIONS: In the majority of patients who survived to be discharged from hospital after combined acute multiple organ and renal failure, the overall state of health and quality of life seemed acceptable. Most patients felt that their treatment was worthwhile and that they would undergo the same treatment again if necessary. Our findings suggest that the cost and effort associated with CRRT and ICU care in these patients are high but broadly comparable to those associated with the care of other serious illnesses. They are also seen as worthwhile by survivors, who consider their life to be of acceptable quality.

APACHE↗
PubMed1997

New CRRT systems: impact on dose delivery.

The evolution of technology and biomaterials has permitted a parallel development of renal replacement therapies in the acute, critically ill patient. From the original description of continuous arteriovenous hemofiltration, new techniques such as continuous venovenous hemofiltration, hemodiafiltration, and high flux dialysis have been developed and clinically used. A parallel improvement in efficiency has been achieved with urea daily clearances as high as 50 L or more. The use of special highly permeable dialyzers has also permitted an increase in the clearances of larger solutes, thus leading to significant removals of chemical substances involved in acute inflammation and sepsis. In this field, recent observations have suggested using hemofiltration with high volumes of fluid exchange. The hardware and software of the newer CRRT systems are key in achieving these results and in safely performing such challenging techniques.

Hemofiltration↗
PubMed1997

Relevance of platelet-activating factor in inflammation and sepsis: mechanisms and kinetics of removal in extracorporeal treatments.

Sepsis can be considered a systemic inflammatory response syndrome (SIRS) caused by infection. When an excessive and/or persistent activation of humoral and cellular mechanisms of host defense is present, an exaggerated and generalized activation of inflammatory mechanisms can lead to a multiple organ dysfunction syndrome. Mediators thought to be involved in this syndrome include the major plasma cascade systems (complement, coagulation, and fibrinolytic systems) and soluble cell-derived mediators (cytokines, reactive oxygen species, platelet-activating factor (PAF), arachidonic acid metabolites, and nitric oxide and related compounds). Several findings indicate that among these mediators, PAF may exert an important role in the pathophysiology of septic shock. Evidence is accumulating that in human sepsis this scenario is far more complicated and that removal of inflammatory mediator excess from plasma, rather than blockade of their potentially beneficial local production, might provide a rationale for the use of continuous renal replacement therapy (CRRT). There is an emerging view that CRRT should be considered in the light of broader concept (ie, the use of blood purification for the treatment of sepsis). Recent studies, performed in an experimental model of continuous arteriovenous hemofiltration with exogenous PAF, demonstrated that polysulfone membranes can adsorb substantial amounts of biologically active PAF. These studies also showed that the removal of this mediator occurs by a two-step process involving early adsorption followed by ultrafiltration. Although the removal of cytokines, such as tumor necrosis factor-alpha (TNF-alpha), remains controversial, mainly because of differences in membrane used, operational conditions, and inter- and intra-assay variability, the crucial point is that no evidence has yet been given to show real benefit from CRRT in significantly reducing the plasma concentration of cytokines. The net advantage of CRRT, however, may not only be the removal of cytokines per se, but also the simultaneous elimination of cytokine-inducing substances. Experimental and human studies will be discussed as to whether extracorporeal treatments may remove an excess of circulating cytokines, either by increasing the turnover rate (the so-called high-volume hemofiltration), or by using sorbent systems to regenerate plasma filtrate.

Adsorption↗
PubMed1997

Beta 2-microglobulin removal by synthetic dialysis membranes. Mechanisms and kinetics of the molecule.

Beta 2-microglobulin (beta 2-m) accumulation represents a possible complication of long term dialysis. It is therefore important to evaluate the capacity of removal of this molecule from the patient by different dialysis membranes. The present study is aimed at evaluating the mechanisms involved in beta 2-m removal by three different synthetic membranes: a) highly asymmetric hydrophobic polysulfone (Biosulfane, NMC), b) moderately asymmetric and hydrophobic polysulfone (PS600, Fresenius), c) Polyacylonitrile (AN69HF, Hospal). The adsorption capacity and sieving coefficients of the three membranes for native and labeled beta 2-m were studied in vitro utilizing human blood. The amount adsorbed by the membrane was measured by the elution of the molecule obtained with a detergent solution. Clearances, total removal and membrane adsorption were studied in six patients treated in a randomized sequence with the three membranes. For this purpose, plasma and dialysate measurements as well as total collection of spent dialysate and beta 2-m elution from the used dialyzers were carried out. Ex novo generation of beta 2-m did not take place during in vitro circulation. The molecule was removed by the studied membranes both by filtration and adsorption. The Biosulfane membrane removed beta 2-m mostly by adsorption while the PS600 membrane removed beta 2-m almost entirely by filtration. Intermediate behaviour was shown by AN69 membrane. Similar quantities of beta 2-m were removed from the patients with the three membranes. Total removal could only be precisely measured by adding the quantity of beta 2-m eluted from the membrane to the amount recovered in the spent dialysate. Out of total removal, adsorption was more than 90% with Biosulfane, while only 5% with the PS600. These findings contribute to the understanding of the discrepancy found between the clearance measured from the plasma side and that measured from the dialysate side. In conclusion, clearance and sieving measurements for beta 2-m cannot be correctly performed unless the capacity of adsorption of the membrane is taken into account.

Acrylic Resins↗
PubMed1997

Impact of spacing filaments external to hollow fibers on dialysate flow distribution and dialyzer performance.

A new type of dialyzer (PAN 650 SF Asahi) is analyzed in terms of hydraulic properties, solute clearances and dialysate flow distribution. The new type of dialyzer is a polyacrylonitrile hollow fiber filter, equipped with spacing filaments placed externally to the fibers to facilitate dialysate distribution and avoid channeling. The new filter is compared with a similar filter without spacing filaments. For this purpose, blood and dialysate side clearances have been measured in sequential dialysis session carried out randomly in the same patients. Furthermore, a last generation helical scanner (X-Press/HS1, Toshiba) has been utilized to analyze in vitro the flow distribution of dialysate inside the dialyzer. A contrast medium was injected and a sequence of images has been achieved on a longitudinal section of the dialyzer. This new method permits to avoid any bias due to the cylindrical shape of the dialyzer, since a 10 mm thick rectangular section is analyzed and not the entire body of the filter. The dialyzers equipped with spacing filaments displayed a significant improvement of the dialysate distribution as demonstrated by the radiological pattern. In detail, despite a channeling phenomenon in the peripherical region of the bundle is still present, this is remarkably reduced in comparison with the channelling phenomenon observed in the standard dialyzers. This improved distribution is confirmed by a significant improvement of the solute clearances.

Dialysis Solutions↗
PubMed1997

[Continuous "high flux" dialysis: an effective renal replacement therapy for intensive care patients].

Currently available replacement therapies for the treatment of acute renal failure are reviewed. Particular interest is focused on their application in intensive care, especially in septic patients. Underlying principles and mechanisms of action are explained. The continuous "High flux-dialysis" is shown to be a particularly effective form of renal replacement therapy.

Acute Kidney Injury↗
PubMed1996

[Evaluation of a stay and care center for drug addicts in Lucerne].

UNLABELLED: Between April 1992 and March 1994 a low threshold centre named "Aufenthalts- und Betreuungsraum für Drogenabhängige (ABfD)" ("Common Care Room for Drug Addicts") was run in the city of Lucerne which intended to help drug addicts to live and survive in terms of harm and risk reduction. The evaluation of the ABfD was conducted by the Institute for Social and Preventive Medicine on behalf of the Federal Office of Health. Combining qualitative and quantitative research methods its structure was evaluated regarding the realization of its own objectives. THE RESULTS: the ABfD was frequented beyond expectation by an average of about 65 male and female drug addicts per evening. All of its facilities were used and appreciated. The clientele of the ABfD was characterized by a great diversity of sociodemographic factors such as age, sex and income as well as housing conditions. The majority were residents of the city (approx. 54%) and the canton of Lucerne (approx. 28%). In general, the ABfD had a positive effect on the physical condition of its user insofar as the distribution of sterile injecting material enabled them to behave more risk consciously. Also, it gave many drug addicts something like a home and the opportunity to experience an atmosphere of solidarity. In spite of isolated criticism the ABfD generally enjoyed great esteem. The evaluation has shown that there is a need for a care center for drug addicts such as the ABfD, that it had been widely made use of, realized many of its objectives and it had no attractive effect on other regions. The researchers concluded by recommending the establishment of an analogous institution within a sensible period of time since with the closing of the ABfD in the Lucerne area the help to live and survive, an important pillar of the drug policy was no longer warranted for.

Adult↗
PubMed1996

[Evaluation of street facilities I, II and III in Basel].

In June 1991 the city of Basel established the first low threshold centre (LTC) subsidized by the government after various private initiatives of "Live & Survive" aids. This low threshold facility which was supplemented in 1992 by two additional LTCs aimed at harm and risk reduction. The evaluation of LTCs was conducted by the institute for Social and Preventive Medicine of the University of Basel on behalf of the Federal Office of Health. Combining qualitative and quantitative research methods its structure was evaluated regarding the realization of its own objectives. The LTCs reached a great variety of drug addicts which were characterized by a remarkable heterogeneity. The majority of users were aged between 20 and 30, a quarter of them were female. Differences were found in housing conditions, subsistence and the degree of social integration. The facilities of the institutions were extensively used. In 1993 and 1994 a daily average of 250 to 300 visits was recorded in the injecting rooms only. the clientele were mainly residents of the Basel area. This lead to the conclusion that there was no attractive effect on more remote regions. As a consequence of the extensive use of the facilities a movement of the drug scene away from the street into the LTCs could be observed. In general, a stabilization or even an improvement of the physical condition of its users could be noticed. Another important feature was the improvement of the drug addicts' social integration. The main reason for this was the relationship between users and staff. Due to the shortage of personnel this promising base for further psychosocial work could not be adequately developed. The investigators not only concluded that there is a need for continuing maintenance of these facilities but also that additional efforts to improve the psychosocial services would be justified.

Adult↗
PubMed1996

Effects of different membranes and dialysis technologies on patient treatment tolerance and nutritional parameters. The Italian Cooperative Dialysis Study Group.

There is increasing evidence that the biochemical and cellular phenomena induced by blood/ membrane/dialysate interactions contribute to dialysis-related intradialytic and long-term complications. However, there is a lack of large, prospective, randomized trials comparing biocompatible and bioincompatible membranes, and convective and diffusive treatment modalities. The primary aim of this prospective, randomized trial was to evaluate whether the use of polysulfone membrane with bicarbonate dialysate offers any advantage (in terms of treatment tolerance, nutritional parameters and pre-treatment beta-microglobulin levels) over a traditional membrane (Cuprophan). A secondary aim was to assess whether the use of more sophisticated methods consisting of a biocompatible synthetic membrane with different hydraulic permeability at different ultrafiltration rate (high-flux hemodialysis and hemodiafiltration) offers any further advantages. Seventy-one Centers were involved and stratified according to the availability of only the first two or all four of the following techniques: Cuprophan hemodialysis (Cu-HD), low-flux polysulfone hemodialysis (LfPS-HD), high-flux polysulfone high-flux hemodialysis (HfPS-HD), and high-flux polysulfone hemodiafiltration (HfPS-HDF). The 380 eligible patients were randomized to one of the two or four treatments (132 to Cu-HD, 147 to LfPS-HD, 51 to HfPS-HD and 50 to HfPS-HDF). The follow-up was 24 months. No statistical difference was observed in the algebraic sum of the end points between bicarbonate dialysis with Cuprophan or with low-flux polysulfone, or among the four dialysis methods under evaluation. There was a significant decrease in pre-dialysis plasma beta 2-microglobulin levels in high-flux dialysis of 9.04 +/- 10.46 mg/liter (23%) and in hemodiafiltration of 6.35 +/- 12.28 mg/liter (16%), both using high-flux polysulfone membrane in comparison with Cuprophan and low-flux polysulfone membranes (P = 0.032). The significant decrease in pre-dialysis plasma beta 2-microglobulin levels could have a clinical impact when one considers that beta 2-microglobulin accumulation and amyloidosis are important long-term dialysis-related complications.

Adolescent↗