Critical care : the official journal of the Critical Care Forum
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Comparative Study
Effects of hydrogen sulfide on hemodynamics, inflammatory response and oxidative stress during resuscitated hemorrhagic shock in rats.
Hydrogen sulfide (H2S) has been shown to improve survival in rodent models of lethal hemorrhage. Conversely, other authors have reported that inhibition of endogenous H2S production improves hemodynamics and reduces organ injury after hemorrhagic shock. Since all of these data originate from unresuscitated models and/or the use of a pre-treatment design, we therefore tested the hypothesis that the H2S donor, sodium hydrosulfide (NaHS), may improve hemodynamics in resuscitated hemorrhagic shock and attenuate oxidative and nitrosative stresses. ⋯ NaHS is protective against the effects of ischemia reperfusion induced by controlled hemorrhage in rats. NaHS also improves hemodynamics in the early resuscitation phase after hemorrhagic shock, most likely as a result of attenuated oxidative stress. The use of NaHS hence appears promising in limiting the consequences of ischemia reperfusion (IR).
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During the past decade, there have been an increasing number of studies investigating the precise role of T regulatory cells in human disease. First recognized for their ability to prevent autoimmunity, T regulatory cells control effector CD4+ and CD8+ T lymphocytes and innate immune cells by several different suppressive mechanisms, like cell to cell contact, secretion of inhibitory cytokines and cytolysis. This suppressive function of T regulatory cells could contribute in a similar way to the profound immune dysfunction seen in critical illness whether the latter is due to sepsis or severe injury.
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Sepsis in critically ill patients is almost associated with bad prognosis and its early detection may improve the prognosis. However, it is difficult to monitor the immunological state of these patients depending on the traditional markers of infection or inflammatory mediators. Accelerated lymphocyte death may reflect good idea about the prognosis especially when combined with 20S proteasome determinations, a recently discovered marker for muscle degradation in patients with sepsis. The hypothesis of the present study is to evaluate the role of serum 20S proteasome at early diagnosis of sepsis and its correlation with lymphocyte apoptosis to predict prognosis and consequently the early interference in critically ill patients suffering from a broad range of diseases in the intensive care unit. ⋯ The correlation of median values of 20S proteasome and the percentage of apoptotic lymphocyte median values could be a good indicator of patient prognosis and survival in critically ill patients.
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The human fetus develops in a profoundly hypoxic environment. Thus, the foundations of our physiology are built in the most hypoxic conditions that we are ever likely to experience: the womb. This magnitude of exposure to hypoxia in utero is rarely experienced in adult life, with few exceptions, including severe pathophysiology in critical illness and environmental hypobaric hypoxia at high altitude. ⋯ Many of these mechanisms act to modify the process of oxygen consumption rather than oxygen delivery in order to maintain adequate tissue oxygenation. The successful activation of such processes may provide a new chapter in the clinical management of hypoxemia. Thus, strategies employed to endure the relative hypoxia in utero may provide insights for the management of severe hypoxemia in adult life and ventures to high altitude may yield clues to the means by which to investigate those strategies.
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Dead space negatively influences carbon dioxide (CO(2)) elimination, particularly at high respiratory rates (RR) used at low tidal volume ventilation in acute respiratory distress syndrome (ARDS). Aspiration of dead space (ASPIDS), a known method for dead space reduction, comprises two mechanisms activated during late expiration: aspiration of gas from the tip of the tracheal tube and gas injection through the inspiratory line - circuit flushing. The objective was to study the efficiency of circuit flushing alone and of ASPIDS at wide combinations of RR and tidal volume (V(T)) in anaesthetized pigs. The hypothesis was tested that circuit flushing and ASPIDS are particularly efficient at high RR. ⋯ At high RR, re-breathing of CO(2) from the y-piece and tubing becomes important. Circuit flushing and ASPIDS, which significantly reduce tubing dead space and PaCO2, merit further clinical studies.