Critical care : the official journal of the Critical Care Forum
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The role played by several vasoactive mediators that are synthesized and released by the pulmonary vascular endothelium in the regulation of hypoxic pulmonary vasoconstriction (HPV) remains unclear. As a potent vasoconstrictor, angiotensin II could be involved. We tested the hypothesis that angiotensin-converting enzyme inhibition by enalaprilat and type 1 angiotensin II receptor blockade by candesartan would inhibit HPV. ⋯ These results suggest that, although the renin-angiotensin system was activated in hypoxia, angiotensin II is not normally involved in mediating acute HPV.
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Consistent data about the incidence and outcome of sepsis in Latin American intensive care units (ICUs), including Brazil, are lacking. This study was designed to verify the actual incidence density and outcome of sepsis in Brazilian ICUs. We also assessed the association between the Consensus Conference criteria and outcome ⋯ Our preliminary data suggest that sepsis is a major public health problem in Brazilian ICUs, with an incidence density about 57 per 1000 patient-days. Moreover, there was a close association between ACCP/SCCM categories and mortality rate.
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Review Historical Article
Bench-to-bedside review: a brief history of clinical acid-base.
The history of assessing the acid-base equilibrium and associated disorders is intertwined with the evolution of the definition of an acid. In the 1950s clinical chemists combined the Henderson-Hasselbalch equation and the Bronsted-Lowry definition of an acid to produce the current bicarbonate ion-centred approach to metabolic acid-base disorders. ⋯ This approach, using the strong ion difference (particularly the sodium chloride difference) and the concentration of weak acids (particularly albumin), pushes bicarbonate into a minor role as an acid-base indicator rather than as an important mechanism. The Stewart approach may offer new insights into acid-base disorders and therapies.
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Krishnan and colleagues have conducted a prospective clinical trial of a weaning strategy previously demonstrated to enhance clinical outcomes of mechanically ventilated patients. They draw conclusions quite different from those drawn in an accompanying editorial. Krishnan and colleagues compared the outcomes of patients supported with mechanical ventilation for at least 24 hours. ⋯ These features might reduce the difference in outcome between the protocol group and other patients in their unit. In addition, the experimental design allowed convergence of the method of care of protocol group patients with the method of care of other patients. Their results are compatible with either no effect of the protocol or with an inability to demonstrate the effect of the protocol because of the systems improvement elements in operation in their intensive care unit.
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This review describes current knowledge on the mechanisms that underlie glucocorticoid insufficiency in sepsis and the molecular action of glucocorticoids. In patients with severe sepsis, numerous factors predispose to glucocorticoid insufficiency, including drugs, coagulation disorders and inflammatory mediators. These factors may compromise the hypothalamic-pituitary axis (i.e. secondary adrenal insufficiency) or the adrenal glands (i.e. primary adrenal failure), or may impair glucocorticoid access to target cells (i.e. peripheral tissue resistance). ⋯ The molecular action of glucocorticoids results in genomic and nongenomic effects. Direct and indirect transcriptional and post-transcriptional effects related to the cytosolic glucocorticoid receptor account for the genomic effects. Nongenomic effects are probably subsequent to cytosolic interaction between the glucocorticoid receptor and proteins, or to interaction between glucocorticoids and specific membrane binding sites.