Contributions to nephrology
-
Endotoxin removal by polymyxin B immobilized cartridge inactivates circulating proapoptotic factors.
Severe sepsis and septic shock continue to be major clinical challenges due to high associated mortality. Lipopolysaccharide (LPS) is a component of the cell membrane of Gram-negative bacteria, and is believed to initiate septic-induced signaling, inflammation and organ damage, including acute renal failure. Polymyxin B (PMX-B) hemoperfusion of septic patients can improve survival and decreasing organ dysfunction by removing circulating LPS. Unfortunately, some clinicians have been slow to adopt this novel therapy due to the lack of understanding of the cellular mechanisms involved in this treatment. Apoptosis, or programmed cell death, is known to contribute to acute renal failure and overall organ dysfunction during sepsis, and can be activated by LPS-initiated signaling pathways. Therefore, the protective renal effects associated with PMX-B hemoperfusion of septic patients may result from alterations in cellular apoptosis. This chapter will review recent data regarding the role of apoptosis prevention in the mechanism leading to the improved outcome and decreased acute renal failure associated with PMX-B hemoperfusion during sepsis. ⋯ The protective effects of extracorporeal therapy with PMX-B on the development of acute renal failure result, in part, through its ability to reduce the systemic proapoptotic activity of septic patients on renal cells.
-
Fluid balance management in pediatric critically ill patients is a challenging task, since fluid overload (FO) in the pediatric ICU is considered a trigger of multiple organ dysfunction. In particular, the smallest patients with acute kidney injury are at highest risk to develop severe interstitial edema, capillary leak syndrome and FO. Several studies previously showed a statistical difference in the percentage of FO among children with severe renal dysfunction requiring renal replacement therapy. ⋯ The present review will shortly describe nutrition strategies in critically ill children, it will discuss dosages, benefits and drawbacks of diuretic therapy, and alternative diuretic/nephroprotective drugs currently proposed in the pediatric setting. Finally, specific modalities of pediatric extracorporeal fluid removal will be presented. Fluid management, furthermore, is not only the discipline of removing water: it should also address the way to optimize fluid infusions and, above all, one of the most important fluids infused to all ICU patients with renal dysfunction: parenteral nutrition.
-
Review Case Reports
Diuretic therapy in fluid-overloaded and heart failure patients.
Diuretics are the most commonly used drugs to treat clinically diagnosed fluid overload in patients with heart failure. There is no conclusive evidence that they alter major outcomes such as survival to hospital discharge or time in hospital compared to other therapies. However, they demonstrably achieve fluid removal in the majority of patients, restore dry body weight, improve the breathlessness of pulmonary edema and are unlikely to be subjected to a large double-blind randomized controlled trial in this setting because of lack of equipoise. ⋯ Such therapy often requires more intensive monitoring than available in medical wards. If diuretic therapy fails to achieve its clinical goals, ultrafiltration by semipermeable membranes is reliably effective in achieving targeted fluid removal. The combination of diuretic therapy and/or ultrafiltration can achieve volume control in essentially all patients with heart failure.
-
Blood purification in critical care can perform 2 main functions: as an artificial support for failing organs (such as artificial kidney or liver support) and as a remover of causative humoral mediators of critical illness (such as severe sepsis and acute respiratory distress syndrome). As an artificial kidney, continuous blood purification (such as continuous hemofiltration and continuous hemodiafiltration, CHDF) is widely applied in intensive care units. The intensity of renal replacement therapy, however, has been reported to have no impact upon the efficacy of the blood purification in terms of clinical outcome. ⋯ However, our understanding of the pathophysiology of sepsis has changed since the concept of pattern recognition receptors and pathogen-associated molecular patterns was introduced. According to this, CHDF with a cytokine-adsorbing polymethylmethacrylate membrane hemofilter is preferable and more effective than direct hemoperfusion with an endotoxin-adsorbing polymyxin-B immobilized column in the treatment of sepsis and septic shock. Blood purification in critical care is gaining popularity, and is widely for both renal and non-renal indications.
-
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.