Contributions to nephrology
-
Sepsis-induced acute kidney injury (AKI) is the most common form of AKI observed in critically ill patients. AKI mortality in septic critically ill patients remains high despite our increasing ability to support vital organ systems. This high mortality is partly due to our poor understanding of the pathophysiological mechanisms of sepsis-induced AKI. ⋯ Sepsis-induced renal microvascular alterations (vasoconstriction, capillary leak syndrome with tissue edema, leukocytes and platelet adhesion with endothelial dysfunction and/or microthrombosis) and/or an increase in intra-abdominal pressure could contribute to an increase in RVR. Further studies are needed to explore the time course of renal microvascular alterations during sepsis as well as the initiation and development of AKI. Doppler ultrasonography combined with the calculation of the resistive indices may indicate the extent of the vascular resistance changes and may help predict persistent AKI and determine the optimal systemic hemodynamics required for renal perfusion.
-
The modern definition and classification of acute kidney injury (AKI) has now been applied to thousands of patients around the world and in different settings. Epidemiology is shedding intense light on the credibility of our fundamental notions of how AKI occurs and why. It is clear from multiple studies that sepsis is the leading etiology of AKI, although other settings associated with systemic inflammation (polytrauma, burns, pancreatitis, cardiopulmonary bypass) also represent important means of exposure. ⋯ Dissonance of mediator secretion and cell responses may lead to persistent injury and de novo chronic kidney disease. A number of soluble mediators initiate a variety of pathophysiological processes as kidney injury evolves. In this chapter, we will discuss the pathogenesis of AKI in light of new information concerning injury and repair, and focus on the controversies arising from emerging evidence.
-
Sustained high-efficiency daily diafiltration using a mediator-adsorbing membrane (SHEDD-fA) is an effective, intensive modality for sepsis treatment. Here we describe the effectiveness of SHEDD-fA, which makes the best use of three principles: dialysis, filtration and adsorption, for mediator removal in the treatment of severe sepsis. SHEDD-fA was initiated after adequate fluid resuscitation and catecholamine support had been provided. ⋯ Because SHEDD-fA is an intensive and high-efficiency modality, removal of useful drugs or nutrients may be observed. Despite the fact that removal of useful substances cannot be ignored, we believe that an appropriate stage or timing can be identified so that we can avoid a vicious cycle and use blood purification with effective diffusion, filtration and adsorption. We demonstrate that SHEDD-fA may be an effective, intensive modality for the treatment of patients with severe sepsis and is a possible modality for cytokine modulation therapy.
-
Continuous hemoperfusion therapies are now widely used in critical care, and could prove to be life-saving for patients unable to receive regular hemoperfusion treatments. Unfortunately, due to the inherent difficulties in assessing the effects of treatment upon critically ill patients, the efficacy of this modality has yet to be proven. Instead of focusing exclusively on a particular form of continuous hemoperfusion or a direct comparison between the different types available, this report provides a general overview of the studies reporting on its efficacy across a wide range of conditions. The authors conclude that continuous hemoperfusion could be beneficial in some cases, but this is highly dependent upon the particular modality used.
-
The correct selection of anticoagulation in acute blood purification is crucial for avoiding exacerbation of bleeding in critical care patients with acute renal failure, as these patients frequently exhibit hemorrhagic complications. The mode of acute blood purification is determined mainly by the patient's hemodynamic stability, and continuous renal replacement therapies (CRRTs) have been extensively performed for patients with hemodynamic instability. Unfractionated heparin, low molecular weight heparin and nafamostat mesilate (nafamostat) are available in acute blood purification for the patients. ⋯ This is especially the case with patients of small stature, which is the case for many Japanese people. Nafamostat can be used safely in CRRT for critical care patients with acute renal failure and bleeding risks, because it acts as a regional anticoagulant due to its pharmacological characteristics. Nafamostat has been widely used in acute blood purification at critical care units in Japan.