[show abstract][hide abstract] ABSTRACT: Managing trauma patients with hemorrhagic shock is complex and difficult. Despite our knowledge of the pathophysiology of hemorrhagic shock in trauma patients that we have accumulated during recent decades, the mortality rate of these patients remains high. In the acute phase of hemorrhage, the therapeutic priority is to stop the bleeding as quickly as possible. As long as this bleeding is uncontrolled, the physician must maintain oxygen delivery to limit tissue hypoxia, inflammation, and organ dysfunction. This process involves fluid resuscitation, the use of vasopressors, and blood transfusion to prevent or correct acute coagulopathy of trauma. The optimal resuscitative strategy is controversial. To move forward, we need to establish optimal therapeutic approaches with clear objectives for fluid resuscitation, blood pressure, and hemoglobin levels to guide resuscitation and limit the risk of fluid overload and transfusion.
[show abstract][hide abstract] ABSTRACT: Despite our increasing ability to support vital organs and resuscitate patients, the morbidity and mortality of acute kidney injury (AKI) remain high in the intensive care unit (ICU). The ability to predict the occurrence of AKI is crucial for the development of preventive strategies. Early diagnosis of AKI requires markers that are sensitive and easily applicable in clinical practice. The use of Doppler ultrasonography to assess renal perfusion is increasing in many kidney diseases and in the ICU. The Doppler-based renal resistive index, which is a simple, rapid, noninvasive, and repeatable marker, could be a promising tool to prematurely detect the patients most at risk of developing AKI in the ICU and to distinguish transient from persistent AKI. Moreover, the resistive index could also be useful to adjust preventive or therapeutic modalities for the kidney perfusion at the bedside. The recent progress in ultrasound with contrast-enhanced ultrasound gives the opportunity to assess not only the kidney macrocirculation but also the kidney microcirculation in the ICU.
[show abstract][hide abstract] ABSTRACT: 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. Recent experimental studies have suggested that the pathogenesis of sepsis-induced AKI is much more complex than isolated hypoperfusion due to decreased cardiac output and hypotension. In nonresuscitated septic patients with a low cardiac output, a decrease in renal blood flow (RBF) could contribute to the development of AKI. In resuscitated septic patients with a hyperdynamic circulatory state, RBF is unchanged or increased. However, in resuscitated septic patients, sepsis-induced AKI can occur in the setting of renal hyperemia in the absence of renal hypoperfusion or renal ischemia. Alterations in the microcirculation in the renal cortex or renal medulla can occur despite normal or increased global RBF. Increased renal vascular resistance (RVR) may represent a key hemodynamic factor that is involved in sepsis-associated 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.
Contributions to nephrology 01/2011; 174:89-97. · 1.49 Impact Factor