Critical care : the official journal of the Critical Care Forum
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The majority of deaths on the intensive care unit now occur following a decision to limit life-sustaining therapy, and end-of-life decision making is an accepted and important part of modern intensive care medical practice. Such decisions can essentially take one of two forms: withdrawing -- the removal of a therapy that has been started in an attempt to sustain life but is not, or is no longer, effective -- and withholding -- the decision not to make further therapeutic interventions. Despite wide agreement by Western ethicists that there is no ethical difference between these two approaches, these issues continue to generate considerable debate. In this article, I will provide arguments why, although the two actions are indeed ethically equivalent, withdrawing life-sustaining therapy may in fact be preferable to withholding.
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Comparative Study
Microvascular permeability during experimental human endotoxemia: an open intervention study.
Septic shock is associated with increased microvascular permeability. As a model for study of the pathophysiology of sepsis, endotoxin administration to humans has facilitated research into inflammation, coagulation and cardiovascular effects. The present study was undertaken to determine whether endotoxin administration to human volunteers can be used as a model to study the sepsis-associated increase in microvascular permeability. ⋯ Although experimental human endotoxaemia is frequently used as a model to study sepsis-associated pathophysiology, an endotoxin-induced increase in microvascular permeability in vivo could not be detected using three different methods. Endotoxin administration to human volunteers is not suitable as a model in which to study changes in microvascular permeability.
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Comparative Study
Increased blood flow prevents intramucosal acidosis in sheep endotoxemia: a controlled study.
Increased intramucosal-arterial carbon dioxide tension (PCO2) difference (DeltaPCO2) is common in experimental endotoxemia. However, its meaning remains controversial because it has been ascribed to hypoperfusion of intestinal villi or to cytopathic hypoxia. Our hypothesis was that increased blood flow could prevent the increase in DeltaPCO2. ⋯ In this model of endotoxemia, intramucosal acidosis was corrected by increased blood flow and so might follow tissue hypoperfusion. In contrast, anion-gap metabolic acidosis was left uncorrected and even worsened with aggressive volume expansion. These results point to different mechanisms generating both alterations.
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Review Comparative Study
Clinical review: Vasopressin and terlipressin in septic shock patients.
Vasopressin (antidiuretic hormone) is emerging as a potentially major advance in the treatment of septic shock. Terlipressin (tricyl-lysine-vasopressin) is the synthetic, long-acting analogue of vasopressin, and has comparable pharmacodynamic but different pharmacokinetic properties. Vasopressin mediates vasoconstriction via V1 receptor activation on vascular smooth muscle. ⋯ Of concern is a constant decrease in cardiac output and oxygen delivery, the consequences of which in terms of development of multiple organ failure are not yet known. Terlipressin (one or two boluses of 1 mg) has similar effects, but this drug has been used in far fewer patients. Large randomized clinical trials should be conducted to establish the utility of these drugs as therapeutic agents in patients with septic shock.