Current opinion in anaesthesiology
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Curr Opin Anaesthesiol · Apr 2009
ReviewApplying gases for microcirculatory and cellular oxygenation in sepsis: effects of nitric oxide, carbon monoxide, and hydrogen sulfide.
Nitric oxide, carbon monoxide, and hydrogen sulfide (H2S) are gases that have received attention as signaling molecules regulating many biological processes. All of them were reported to have beneficial effects in inflammatory states, in particular for microcirculatory perfusion and tissue energy balance. Thus, this review will highlight the most important results with a focus on resuscitated, clinically relevant experimental models and, if available, human studies. ⋯ It is still a matter of debate whether manipulating nitric oxide, carbon monoxide, or H2S tissue concentrations, either by using the inhaled gas itself or by administering donor molecules or inhibitors of their endogenous production, is a useful therapeutic approach to improve microcirculatory blood flow, tissue oxygenation, and cellular respiration. This is mainly due to their 'friend and foe character' documented in various experimental models, but also to the paucity of data from long-term, resuscitated large animal experiments that fulfil the criteria of clinically relevant models.
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Curr Opin Anaesthesiol · Apr 2009
ReviewAlterations of mitochondrial function in sepsis and critical illness.
Septic shock is the consequence of a conflict between a pathogenic agent and the immune system of the host. This conflict induces an immune-mediated cytokine storm, with a whole-body inflammatory response often leading to multiple organ failure. Although extensively studied, the pathophysiology of sepsis-associated multiorgan failure remains unknown. One postulated mechanism is changes in mitochondrial function with an inhibition of mitochondrial respiratory chain and a decrease of oxygen utilization. ⋯ A pivotal role is suggested for mitochondrial dysfunction during the occurrence of multiorgan failure. Understanding the precise effect of sepsis on the mitochondrial function and the involvement of mitochondria in the development of multiple organ failure is fundamental. More human studies are thus necessary to clarify the mitochondrial dysfunction in the various phases of sepsis (early and late phase) before testing therapeutic strategies targeting mitochondria.
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Curr Opin Anaesthesiol · Apr 2009
ReviewMicrocirculatory effects of intravenous fluids in critical illness: plasma expansion beyond crystalloids and colloids.
Plasma expanders are reviewed to determine their ability to restore microvascular function as a means for extending the transfusion trigger and delaying the use of blood transfusions. This outcome is currently achievable because of the emergence of a new understanding of optimal tissue function that prioritizes maintenance of functional capillary density, which results from the normalization of blood viscosity via the increase in plasma viscosity with new viscogenic colloids. ⋯ Preclinical studies show that polyethylene glycol-conjugated albumin at concentrations in the range of 2-4% extends the transfusion trigger, providing the more extended and complete microvascular and systemic recovery from hemorrhagic shock, extreme hemodilution and endotoxemia, postponing the need of reestablish intrinsic blood oxygen-carrying capacity to hemoglobin concentrations lower than those associated with accepted transfusion triggers.
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Curr Opin Anaesthesiol · Apr 2009
ReviewRole of storage time of red blood cells on microcirculation and tissue oxygenation in critically ill patients.
To review the current literature on the role of storage time of transfused red blood cells on microcirculation and tissue oxygenation in critically ill patients. ⋯ Large-scale prospective randomized trials are needed to explicitly clarify the role of new transfusion triggers, such as tissue oxygenation, and the impact of storage lesions of packed red blood cells on tissue oxygenation and--more important--on clinical outcomes in different patient populations.
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Curr Opin Anaesthesiol · Apr 2009
ReviewLink between coagulation abnormalities and microcirculatory dysfunction in critically ill patients.
The current review discusses the role of coagulation in microcirculatory abnormalities and whether anticoagulants may improve microvascular perfusion. ⋯ The activation of coagulation may play an indirect role in microvascular dysfunction, through interplay with endothelium and inflammation.