Kidney international. Supplement最新文献

Temporary vascular access is an essential component to perform any extracorporeal renal replacement therapy (RRT) in the acute renal failure patient. RRT used in the acute setting may be categorized in two groups: intermittent (IRRT) and continuous (CRRT). Therapeutic indications are based on clinical and technical considerations. Continuous modalities are mainly utilized in intensive care units for hemodynamically compromised patient. Initially performed spontaneously via an arteriovenous circuit, CRRT modalities have progressively become venovenous with the circulatory assistance of a blood pump. Since both intermittent and continuous RRT modalities are now performed almost exclusively by venovenous modalities, this article deals exclusively with temporary venous catheters. At present, double-lumen catheters represent the most common vascular access for RRT modalities. Semi-rigid polyurethane catheters currently used in case of emergency are limited to short term use. Hemocompatible, flexible silicone catheters, less aggressive for the vessels, seem better suited for the medium and long term run. The tunneled silicone catheters (DualCath type) meet the short and long term needs, and allow for blood flow rates up to 400 ml/min. The internal jugular vein, particularly the right one, seems to warrant the proper functioning of catheters while reducing the risk of stenotic complications. Subclavian access should be limited in time and reserved for silicone catheters in order to limit the risk of stenosis and/or thrombosis. Femoral access, very useful in cases of emergency and respiratory problems, greatly impairs the patient's mobility and should be limited by time to prevent thrombosis and/or infection. Late and/or delayed dysfunctioning of catheters are indicative of a thrombosis. Performance standards of catheters are less of a limiting factor in continuous low flow RRT modalities than in the intermittent ones. Finally, careful handling of the catheter essential to prevent infectious complications.

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 (CAVH), new techniques such as continuous venous venous hemofiltration (CVVH), hemodiafiltration (HDF) and high flux dialysis (HFD) have been developed and clinically utilized. A parallel improvement in efficiency has been achieved with daily clearances of urea as high as 50 liters or more. The use of special highly permeable dialyzers has also permitted increases in the clearances of larger solutes, thus leading to significant removals of chemical substances involved the acute inflammation and sepsis. In this field, recent observations have suggested the use of hemofiltration with high volumes of fluid exchange. The hardware and software of the newer continuous renal replacement therapy (CRRT) systems are certainly the key points in achieving these results and in safely performing such challenging techniques.

Acute renal failure (ARF) is at a crossroads between nephrology and intensive care medicine. However, there seems to be wide differences between the ARF observed in the intensive care unit (ICU) compared to that observed in other areas of the hospital, particularly when examining the mortality rate. Among the ICU patients the 70% mortality rate is higher to the 50% found in an overall series of studies. Recently, Druml proposed that there is a changing trend in the clinical spectrum of ARF as a convincing reason to justify these differences. According to him, we are moving from an ARF seen as a mono-organ failure to another one observed in a multiorgan dysfunction syndrome (MODS) context. Although extremely coherent, this hypothesis has not been fully confirmed in a prospective study. In fact, most authors seem to look at the problem from opposite sides of the river, either from the critical medicine or the nephrological bank. To the best of our knowledge, only one retrospective study has dealt with this topic by comparing outcome of ARF in ICU and non-ICU patients. In this article we aim to overcome this problem by reviewing the data of the prospective epidemiological ARF study carried out in Madrid using two different approaches: (1) comparing the ARF cases observed in the ICU setting with those ARF studied outside the ICU, and (2) comparing the outcome of isolated ARF with the outcome of ARF as part of a MODS in patients treated in both settings.

The armamentarium of the critical care nephrologist contains several vasoactive and inotropic drugs with powerful effects on the systemic circulation. The physiologically logical use of these drug can be life-saving and have important beneficial effects on renal function. Such drug use must absolutely not be based on a "fixed dosage," but must instead be goal-directed with the aim of achieving those physiological states associated with hemodynamic stability and adequate vital organ perfusion. The achievement and maintenance of these goals must be prompt and guided by appropriate invasive hemodynamic monitoring and may require frequent changes in dosage. When these measures are adhered to, renal protection and clinical success are a much more likely outcome than when stereotyped approaches are followed.