Critical care clinics
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Critical care clinics · Apr 2010
ReviewOxygen delivery and consumption: a macrocirculatory perspective.
Severe sepsis is a leading cause of death and resource use throughout the world. This article examines the relationship of oxygen delivery to oxygen use under varying conditions. Topics reviewed include the concept of the critical dissolved oxygen, concerns over shared measurement errors in obtaining estimates of oxygen consumption, seminal articles in this area, and the practice of early goal directed therapy.
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Organ function is critically linked to the way tissues use available oxygen. In sepsis, tissue-related hypoxic injury is the result of hypoxemia and hypoperfusion and cytokine-mediated mitochondrial dysfunction termed cytopathic hypoxia. ⋯ Lactate is a marker of aerobic mitochondrial dysfunction and anaerobic tissue metabolism and in some circumstances is considered the fuel of choice for certain tissues. The concept of cellular metabolic derangement or cytopathic hypoxia as a potential cause for multiorgan system dysfunction in sepsis may direct efforts to optimize outcome in septic patients from the classic targets of CO, tissue perfusion, DVo(2), and Vo(2) toward moderating sepsis-related early cytokine response, maximizing mitochondrial function, and using biomarkers to monitor treatment response.
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Critical care clinics · Apr 2010
The role of echocardiography in hemodynamic assessment of septic shock.
Echocardiography is a rapid, noninvasive, comprehensive cardiac assessment option for patients presenting with hemodynamic instability. In patients with septic shock, echocardiography can be used to guide fluid therapy by measuring collapsibility of the inferior vena cava. ⋯ Unexpected or rare findings that affect management may be revealed using focused echocardiography. This article presents national and international competency statements regarding critical care echocardiography and training resources for intensivists.
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This article focuses on static methods for determining preload, specifically pressure and volumetric indices measured at the bedside. The underlying ventricular function will determine where the patient is located on Frank-Starling ventricular function curve and the patient's response to a fluid challenge. The proper interpretation and use of such measures, coupled with an understanding of their limitations and knowledge of alternative methods, is necessary to guide properly volume resuscitation in the critically ill.
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Critical care clinics · Apr 2010
Techniques for determining cardiac output in the intensive care unit.
To achieve the goals of resuscitation in critically ill patients, a thorough understanding of the techniques available to measure cardiac output is important. Recently the pulmonary artery catheter has fallen out of favor because of concerns of safety and a lack of efficacy. ⋯ But is important to remember that the ability of these techniques to improve outcome has yet to be demonstrated, and one should apply caution in how they are used until their use in algorithmic treatment approaches have been shown to improve outcome. This article discusses the invasive and noninvasive techniques to assess cardiac output.