Critical care : the official journal of the Critical Care Forum
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Although inhalation of 80 parts per million (ppm) of hydrogen sulfide (H2S) reduces metabolism in mice, doses higher than 200 ppm of H2S were required to depress metabolism in rats. We therefore hypothesized that higher concentrations of H2S are required to reduce metabolism in larger mammals and humans. To avoid the potential pulmonary toxicity of H2S inhalation at high concentrations, we investigated whether administering H2S via ventilation of an extracorporeal membrane lung (ECML) would provide means to manipulate the metabolic rate in sheep. ⋯ Administration of up to 300 ppm H2S via ventilation of an extracorporeal membrane lung does not reduce VCO2 and VO2, but causes dose-dependent pulmonary vasoconstriction and systemic vasodilation. These results suggest that administration of high concentrations of H2S in venoarterial cardiopulmonary bypass circulation does not reduce metabolism in anesthetized sheep but confers systemic and pulmonary vasomotor effects.
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Increasing evidence suggests that the secondary phase of sepsis (that is, after the first proinflammatory hours) is characterized by the occurrence of a systemic failure of the immune system. In the most immunodepressed patients, therapies could be used to restore normal immune functions. ⋯ Of these biomarkers, diminished monocyte HLA-DR expression has rapidly become the most popular. Herein, novel perspectives regarding monocyte HLA-DR assessed as a dynamic parameter in septic patients will be discussed in the context of a recently published study investigating daily evolution of monocyte HLA-DR with regard to 28 day-mortality after severe sepsis.
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Several studies have demonstrated that perioperative hemodynamic optimization has the ability to improve postoperative outcome in high-risk surgical patients. All of these studies aimed at optimizing cardiac output and/or oxygen delivery in the perioperative period. We conducted a survey with the American Society of Anesthesiologists (ASA) and the European Society of Anaesthesiology (ESA) to assess current hemodynamic management practices in patients undergoing high-risk surgery in Europe and in the United States. ⋯ In conclusion, these results point to a considerable gap between the accumulating evidence about the benefits of perioperative hemodynamic optimization and the available technologies that may facilitate its clinical implementation, and clinical practices in both Europe and the United States.
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In this issue of Critical Care, Patschan and colleagues present a study of endothelial progenitor cells (EPCs) in patients with sepsis. The importance of this study is in focusing attention on several frequently ignored aspects of sepsis. ⋯ Other important aspects of the study are the regenerative capacity of mobilized EPCs and the dissociation between the numerical value and clonogenic competence. Attempting to restore the competence to EPCs should be a priority in the future.
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Editorial Comment
Finding new therapies for sepsis: the need for patient stratification and the use of genetic biomarkers.
Reversing the immunoparalysis associated with septic shock remains a priority for improving the outcome of patients suffering from sepsis. The efficacy of future therapies may be better studied under an effective system of patient stratification. Gene expression biomarkers offer a mechanism by which patients may be appropriately stratified in such clinical trials.