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Search Results: 1 - 10 of 7566 matches for " Claudio Ronco "
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N-GAL: Diagnosing AKI as soon as possible
Claudio Ronco
Critical Care , 2007, DOI: 10.1186/cc6162
Abstract: The issue of the early diagnosis of acute kidney injury (AKI) has been debated for years. Partially this has been due to the lack of a suitable and consistent definition. Other limitations are the paucity of available experimental models of AKI and the inadequate capability of selected marker molecules to detect the impairment of kidney function in real time. The article by Zappitelli et al. on neutrophil gelatinase-associated lipocalin (NGAL) as an early marker of acute kidney injury has partially overcome the above mentioned limitations and seems to demonstrate that diagnosing AKI in its early stages is possible and useful [1].AKI prevention and therapy has as of yet been rather unsuccessful and unsatisfactory. The problem may lie in the inadequacy of the renal replacement therapies that we have applied so far; however, this is questionable and it only applies to the late stages of AKI, when the organ function has been lost and replacement by artificial organ support is required. There are many contributions showing that technology has evolved in parallel with the worsening of the clinical conditions of the patients being treated, and it is because of this that the mortality in this condition has not changed over the years [2,3]. This myth is finally undergoing scientific scrutiny and the reality is emerging. We are now realizing that for a number of non-complicated AKI cases, mortality can be significantly reduced especially if an adequate renal replacement therapy is provided [4]. Nevertheless, high mortality rates still pertain to complicated cases associated to multiple organ failure or septic syndromes [5].The story of early diagnosis is different. Only recently have we discovered that most of the preventive measures for AKI which are efficacious in the experimental settings do not show comparable positive results in the clinical setting [6]. This can be explained by the inability to identify the time of injury in the clinical setting. In the experimental mod
Extracorporeal therapies in acute rhabdomyolysis and myoglobin clearance
Claudio Ronco
Critical Care , 2004, DOI: 10.1186/cc3055
Abstract: Rhabdomyolysis is a pathogenetic cause of acute kidney injury in a large number of cases where traumatic or non-traumatic causes induce muscle cell disruption [1]. Naka and colleagues concluded an interesting study on myoglobin clearance by hemofiltration using a 'super-high-flux' membrane in a case of acute rhabdomyolysis [2].The paper is of peculiar interest for several reasons. First, because of the renal damage induced by circulating myoglobin, not only should therapeutic strategies be implemented to replace the failing kidney function, but preventive measures should also be explored to prevent further damage due to renal tubular obstruction, altered intrarenal hemodynamics and tubular cell dysfunction. So far, acute kidney failure has been treated by classical methods of renal replacement therapies, while protective measures have been limited to volume expansion by alkaline fluids and forced diuresis by osmotic diuretics. Second, all attempts to produce a significant removal of myoglobin by extracorporeal therapies have so far displayed controversial results but in general they have been proved to be modestly useful. Thus, although the rationale for a quick and effective removal of myoglobin in acute rhabdomyolysis would be strong and logical, the practical results obtained with traditional methods have been disappointing. The inefficient removal of myoglobin results in a permanently high circulating level of the molecule and a perpetuation of the pathological insult with prolongation of anuria and delay of renal function recovery.Why are extracorporeal techniques hardly effective in removing myoglobin? There are several reasons that depend on the nature of the molecule, on its distribution in the organism, on the mechanism of solute transport and on the structure of the membrane in the extracorporeal technique.Myoglobin has a molecular mass of 17 kDa but because it is non-spherical and carries electrical charges it can be considered to be a solute with an Eins
The place of early haemoperfusion with polymyxin B fibre column in the treatment of sepsis
Claudio Ronco
Critical Care , 2005, DOI: 10.1186/cc3890
Abstract: A few years ago a new device for extracorporeal removal of circulating endotoxin entered the market (Toraymixin; Toray Industries, Osaka, Japan). The device uses polystyrene fibres coated with polymyxin B (which adheres via covalent bonds) that are incorporated in a sorbent column; this column is then used in an extracorporeal haemoperfusion circuit. The device is intended to be used as an adjuvant therapy, adsorbing endotoxin and other products and possibly improving the altered immunohomeostasis characteristic of Gram-negative sepsis in critically ill patients. A report by Kushi and coworkers [1] presents important evidence for a positive impact of the device on outcome in septic patients.Several other reports have been published, but these have often presented confusing or conflicting results [2-5]. Nevertheless, polymyxin B-immobilized fibre (PMX-F) has been used routinely in Japan since 1995, and more than 50,000 septic patients have been treated. So, is it now possible to determine a clear role of PMX-F treatment in the therapy of sepsis? What work has been done thus far, and what must be added to the research agenda if we are to complete our evaluation?The proposal that the toxic molecule polymyxin B, bound to fibres, be placed in contact with circulating blood promptly led to concerns about safety and biocompatibility. This is logical because use of haemoperfusion devices has been reported to result in thrombocytopenia and leucocytopenia. There was additional concern that polymyxin B could be released into the circulation. However, these fears were laid to rest when data indicating excellent biocompatibility were reported [6-8]. Nevertheless, PMX-F treatment is contra-indicated in patients in whom the use of heparin would cause uncontrolled bleeding or in whom adequate anticoagulation cannot safely be achieved, such as those with haemophilia or with known hypersensitivity to heparin or PMX-F.The PMX-F cartridge has been studied in vitro and in animals and hu
Recent evolution of renal replacement therapy in the critically ill patient
Claudio Ronco
Critical Care , 2005, DOI: 10.1186/cc4843
Abstract: In the past decade, the change in the epidemiology of acute renal failure has made critical care nephrology an emerging sub-speciality of intensive care medicine. Dedicated literature and a series of physicians and nurses have made an effort to bridge the knowledge and experience from nephrology and critical care medicine in response to an increased incidence of acute kidney injury in intensive care unit (ICU) patients [1].The origin of this process can definitely be found in the mid 1970s, when continuous arteriovenous hemofiltration (CAVH) appeared on the scene. CAVH has been a tool that has permitted the treatment of patients with acute kidney injury in which peritoneal dialysis or hemodialysis were clinically or technically precluded [2]. This opened the doors of ICUs to a dedicated dialysis technology that experienced a flourishing evolution in subsequent years. Within a few years, continuous veno-venous hemofiltration (CVVH) replaced CAVH because of its improved performance and safety. The advance was made possible by the use of blood pumps, calibrated ultrafiltration control systems and double lumen venous catheters. In the late 1980s, specific machines for continuous renal replacement therapies (CRRTs) were designed and a new era of renal replacement in the critically ill patient began [3]. The therapy started to be standardized and clear indications began to be defined.The evolution of technology did not stop, however, and the recent demand for higher efficiency and exchange volumes has spurred new interest in a further generation of machines with better performance, integrated information technology and easy to use operator interfaces. An example of such technological evolution is represented by the passage from CAVH systems to the BSM 22 and Prisma machines to the most recently developed Prismaflex machine (Gambro Dasco, Mirandola, Italy; Fig. 1). A schematic drawing of different techniques available today for the therapy of the critically ill patient wit
Year in review 2007: Critical Care – nephrology
Zaccaria Ricci, Claudio Ronco
Critical Care , 2008, DOI: 10.1186/cc6952
Abstract: Original research in the field of critical care nephrology has produced in 2007 interesting results on different aspects of acute kidney injury (AKI), that are expected to provide relevant information in the next years. The definition of AKI and the validation of severity of disease criteria have been exstensively evaluated and revised. The research on clinical and experimental utilization of novel biomarkers for the diagnosis of AKI and especially of neutrophil gelatinase-associated lipocalin protein is promising early diagnosis of kidney injury. The outcome of acute kidney injury in the last 10 years has not significantly changed, but this finding must be evaluated with great attention. New approaches to manage circuit patency and extracorporporeal circuits blood flow rate have been scarcely studied in the last years and new experimental and clinical trials are welcome.Reminiscent of the acute lung injury/acute respiratory distress syndrome consensus criteria [1], the epidemiology of AKI, as defined by RIFLE criteria (Risk, Injury, Failure, Loss and End-stage kidney disease), is becoming clearer. It now appears that kidney dysfunction is often under-recognized, although its severity is clearly associated with outcome. AKI is now considered the correct nomenclature for the clinical disorder formerly termed 'acute renal failure' (ARF). This new taxonomy underscores the fact that AKI exists along a continuum, recognizing that the greater the severity of injury, the more likely it is that the overall outcome will be unfavourable. AKI is not acute tubular necrosis and it is not ARF. Rather, it includes both as well as other, less severe conditions that are not necessarily 'structural damage' but also include 'dysfunction' (slight, apparently innocuous increases in serum creatinine; decreases in urine output due to volume depletion, generally defining prerenal ARF, with the implied and flawed meaning of a benign and reversible form of renal dysfunction). Instead of focu
Year in review 2009: Critical Care - nephrology
Zaccaria Ricci, Claudio Ronco
Critical Care , 2010, DOI: 10.1186/cc9277
Abstract: Acute kidney injury (AKI) has been proven to increase patient mortality in all clinical settings: general out-of-hospital population, in-hospital admissions, adult and pediatric intensive care units (ICU), adult and pediatric cardiac surgery, and (last but not least) the relatively high portion formed by post-operative general surgery patients. In a study population of 1,166 patients without previous renal insufficiency, Abelha and colleagues [1] elegantly showed that 7.5% met AKI criteria. Interestingly, AKI was diagnosed when criteria of class I (or greater) of the Acute Kidney Injury Network (AKIN) classification were present. On multivariate analysis, American Society of Anesthesiologists (ASA) physical status, Revised Cardiac Risk Index (RCRI) score, high-risk surgery, and congestive heart failure were identified as the independent pre-operative risk factors for AKI during the post-operative period. The RCRI score includes the following variables: high-risk surgery, ischemic heart disease, congestive heart failure, cerebrovascular disease, and insulin-requiring diabetes mellitus. According to these data, AKI patients were the most severely ill after ICU admission (higher Simplified Acute Physiology Score II and Acute Physiology and Chronic Health Evaluation II), had the longest ICU length of stay, and were independently at risk for hospital mortality. In our opinion, even if the accompanying editorial points out that one of the most important limitations of this report was the exclusion of patients with pre-operative renal dysfunction [2] (which has been identified as a major risk factor for peri-operative AKI in most studies), patients with pre-operative renal dysfunction are already those who receive the greater attention for prevention or treatment (or both) of further renal insult. So it must be remarked that an important message of this study is that post-operative AKI must be suspected in all patients with the clinical characteristics analyzed by Abelha a
Year in review 2005: Critical Care – nephrology
Zaccaria Ricci, Claudio Ronco
Critical Care , 2006, DOI: 10.1186/cc4998
Abstract: During 2005, Critical Care accepted and published articles of original research focused on critical care nephrology and renal replacement therapy (RRT). These studies included papers on epidemiology, prognosis and medical therapy of acute renal failure (ARF), the issue of continuous RRT (CRRT) dose and alternative indications to extracorporeal therapies.We present a review of these papers and other key articles on critical care nephrology published in 2005.To assess changes in renal blood flow (RBF) in human and experimental sepsis, and to identify determinants of RBF, Langenberg and co workers [1] performed an electronic database search and tried to identify experimental and human studies of septic acute renal failure in which RBF was measured. Surprisingly, they found that no human studies measured RBF with suitably accurate direct methods. Where it was measured in septic patients, however, RBF was increased compared with normal. The authors concluded that the impact of sepsis on RBF in humans is unknown. When examined in experimental models of sepsis, RBF was decreased in two-thirds of studies (62%) and unchanged or increased in one-third (38%). Multivariate analysis suggested that cardiac output might have a substantial effect on RBF during experimental sepsis, such that, in the presence of a decreased cardiac output, RBF is typically decreased, whereas in the presence of a preserved or increased cardiac output RBF is typically maintained or increased. This extensive analysis introduces a provocative hypothesis in the physiopathology of ARF: the traditional mechanism of ischemic ARF in critically ill septic patients is put to discussion and, if confirmed by specifically designed experimental and human studies, it could provide new important information about the prevention and therapy of septic ARF.The impact on mortality of severe ARF (sARF), defined as the requirement for RRT with evidence of renal dysfunction (serum creatinine >150 mmol/l) during intensive ca
Year in review: Critical Care 2004 – nephrology
Zaccaria Ricci, Claudio Ronco
Critical Care , 2005, DOI: 10.1186/cc3791
Abstract: During 2004 Critical Care accepted and published original research articles focused on nephrology and renal replacement therapy (RRT). These studies included reports on various aspects of acute renal failure (ARF), acid–base approach and treatment, and RRT insights into specific blood purification issues. We present a review of these papers and other key articles on critical care nephrology published in 2004.Despite several advances in treatment and in our understanding of the pathogenesis of ARF, many important issues in this field remain subject to controversy, confusion and lack of consensus. One such issue is the definition of ARF. In fact, because ARF is mostly an artificial concept, it can neither be proved nor disproved that an individual has ARF unless one agrees what the term means in advance. A clear consensual definition is needed if we are to describe and understand the epidemiology of ARF, randomize patients in controlled trials, test therapies in similar groups of patients, develop animal models and validate diagnostic tests. In this regard ARF is no different from acute respiratory distress syndrome, severe sepsis, or septic shock.In order to make consensus based recommendations and delineate key questions for future studies, the Acute Dialysis Quality Initiative workgroup identified topics relevant to the field of ARF [1], among which a definition/classification system for ARF was ranked highest in terms of importance and clinical impact [2]. The workgroup considered the definition of ARF to require the following features: ease of use and clinical applicability in different centres; high sensitivity and specificity for different populations and research questions; consideration of creatinine change from baseline; and implementation of classifications for acute on chronic renal disease. A classification system should therefore include and differentiate mild and severe, and early and late cases. This would allow such a classification to identify patien
Continuous haemofiltration in the intensive care unit
Rinaldo Bellomo, Claudio Ronco
Critical Care , 2000, DOI: 10.1186/cc718
Abstract: "The difficulty lies, not in new ideas, but in escaping old ones, which ramify for those brought up with them, as most of us have been, into every corner of our minds."John Maynard Keynes (1933)Since its first description [1] continuous hemofiltration, or `continuous renal replacement therapy' (CRRT) as it is now called, has undergone remarkable growth [2]. In the modern ICU, CRRT is now performed using pump technology [3] and double-lumen central venous access [4]. In many ICUs, especially in Australia and in Europe, CRRT has become the dominant if not exclusive form of artificial renal support [5]. Furthermore, there has been growing research into its role as adjuvant therapy in sepsis [6]. Modifications to standard CRRT circuits are also being explored in an effort to increase such anti-inflammatory potential [7]. In the present review, we describe the current technology and state of CRRT in the ICU, address some of the controversies that surround its application in critically ill patients, and attempt to give the reader a state-of-the art view of its uses and clinical future.Continuous arteriovenous therapies were first used for CRRT because they are simple and do not require a peristaltic blood pump. As such, they may have a place under emergency circumstances or in developing countries. However, the morbidity associated with arterial cannulation is substantial [8], and the cost of a simple blood pump module is only £2500. Thus, if one can afford to have an ICU at all, one can afford to have venovenous CRRT, which is much safer for the patient (Fig. 1) [8,9,10]. All CRRT modalities should now be venovenous.Once venovenous therapy is applied, blood flow rate must be controlled. A peristaltic pump module is necessary to achieve this goal. This module must have the appropriate air-trap and pressure monitors to ensure patient safety. In this setting, either continuous venovenous haemofiltration (CVVH) or continuous venovenous haemodialysis (CVVHD), or a combination
Year in review 2008: Critical Care - nephrology
Zaccaria Ricci, Claudio Ronco
Critical Care , 2009, DOI: 10.1186/cc7961
Abstract: Steinvall and colleagues conducted a cohort study on patients with a percentage burned total body surface area of 20% or more [1]. Acute kidney injury (AKI) was classified according to the Risk, Injury, Failure, Loss of kidney function, and End-stage (RIFLE) kidney disease international consensus classification [2]. They evaluated 127 patients, which corresponded to 0.11 per 100,000 people per year. Of these, 31 patients (24%) developed AKI (12% Risk, 8% Injury, and 5% Failure) and four patients (3%) required dialysis. The mean age was 40.6 years, the percentage burned total body surface area was 38.6%, and 25% were women. Renal dysfunction occurred within 7 days in 55% of the patients and after 7 days in the remainder. AKI recovered among all survivors. Age, percentage burned total body surface area, and extent of full-thickness burns were higher among the patients who developed AKI. Pulmonary dysfunction and systemic inflammatory response syndrome were present in all of the patients with AKI and developed before AKI onset. Sepsis was a possible aggravating factor in AKI in 48% of patients. Extensive deep burns (25% or more full-thickness burn) increased the risk for developing early AKI (risk ratio, 2.25). Mortality was 14% and, interestingly, increased with increasing RIFLE class (7% normal, 13% Risk, 40% Injury, and 83% Failure).As the accompanying editorial correctly points out [3], even if the number of patients generally evaluated in post-burn AKI studies is generally low, the analysis from Steinvall and colleagues relates to another two studies on this subject [4,5]: all three studies confirmed that increasing RIFLE class was associated with a stepwise increase of mortality. The incidence of AKI in the studies of Coca and colleagues and of Steinvall and colleagues (26.6% and 24.4%, respectively), however, was significantly lower than that of Lopes and colleagues (35.7% incidence). This difference might be explained by the fact that Lopes and colleagues class
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