Critical care : the official journal of the Critical Care Forum
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Numerous lines of evidence support the premise that withholding and withdrawing life support measures in the intensive care unit are not the same. These include questionnaires, practical observations and an examination of national medical guidelines. It is important to distinguish between the two end of life options as their outcomes and management are significantly different. Appreciation of these differences allows the provision of accurate information, and facilitates decision making that is compassionate, caring and adherent to the needs of the patient and their family.
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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.
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Stewart's quantitative physical chemical approach enables us to understand the acid-base properties of intravenous fluids. In Stewart's analysis, the three independent acid-base variables are partial CO2 tension, the total concentration of nonvolatile weak acid (ATOT), and the strong ion difference (SID). Raising and lowering ATOT while holding SID constant cause metabolic acidosis and alkalosis, respectively. ⋯ Stored whole blood has a very high effective SID because of the added preservative. Large volume transfusion thus causes metabolic alkalosis after metabolism of contained citrate, a tendency that is reduced but not eliminated with packed red cells. Thus, Stewart's approach not only explains fluid induced acid-base phenomena but also provides a framework for the design of fluids for specific acid-base effects.
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Comparative Study
Extravascular lung water in patients with severe sepsis: a prospective cohort study.
Few investigations have prospectively examined extravascular lung water (EVLW) in patients with severe sepsis. We sought to determine whether EVLW may contribute to lung injury in these patients by quantifying the relationship of EVLW to parameters of lung injury, to determine the effects of chronic alcohol abuse on EVLW, and to determine whether EVLW may be a useful tool in the diagnosis of acute respiratory distress syndrome (ARDS). ⋯ More than half of the patients with severe sepsis but without ARDS had increased EVLW, possibly representing subclinical lung injury. Chronic alcohol abuse was associated with increased EVLW, whereas lower EVLW was associated with survival. EVLW correlated moderately with the severity of lung injury but did not account for all respiratory derangements. EVLW may improve both risk stratification and management of patients with severe sepsis.