Best practice & research. Clinical anaesthesiology
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Best Pract Res Clin Anaesthesiol · Dec 2016
ReviewRed blood cell transfusion and its effect on microvascular dysfunction in shock states.
Among critically ill patients, red blood cell (RBC) transfusion is often prescribed for anemia in the absence of active or recent bleeding. The failure of RBC transfusion to improve physiological parameters and clinical outcomes in this setting may be explained by current understanding of the relationship between the RBCs and the microcirculation. It is now evident that the circulating RBCs contribute to microcirculatory hypoxic vasodilation by regulated nitric oxide (NO)-dependent vasodilation, thereby facilitating delivery of oxygen to oxygen-deprived tissue. ⋯ In recent years, there has been a significant focus on the dysfunctional interaction between stored RBCs and the microcirculation, with emphasis on understanding the mechanisms that drive erythrocyte NO-mediated vasodilation. The development of technology that allows noninvasive observation of the microcirculation in humans has allowed for direct observation of the microcirculation immediately before and after RBC transfusion. The current understanding of RBC NO-mediated vasodilation and the results of direct observation of the microcirculation in the setting of RBC transfusion are reviewed.
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Best Pract Res Clin Anaesthesiol · Dec 2016
ReviewLactate levels and hemodynamic coherence in acute circulatory failure.
In this review, the relationship between changes in macrohemodynamics during the development and treatment of acute circulatory failure is discussed in the context of coherence with microcirculation and changes in lactate. In models of circulatory failure, coherence between changes in macrocirculatory and microcirculatory perfusion and coherence with subsequent changes in lactate levels are more or less preserved. ⋯ Resuscitation should therefore aim at adequate tissue perfusion where systemic hemodynamics, microcirculatory perfusion parameters, and lactate levels should be used in their relevant context. This results in treating the individual patient as an n = 1 experiment.
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Best Pract Res Clin Anaesthesiol · Dec 2016
ReviewEffect of non-adrenergic vasopressors on macro- and microvascular coupling in distributive shock.
The present review initially describes the rationale for the use of non-adrenergic vasopressors in the treatment of distributive shock and then provides an overview of the individual vasopressin-receptor agonists, namely arginine vasopressin, terlipressin, and selepressin. Following a brief summary of their current use in clinical practice, the present review focuses on the influence of vasopressin-receptor agonists on macro- and microvascular coupling, also referred to as hemodynamic coherence. ⋯ A higher selectivity for the V1a-receptor seems to be beneficial; however, future clinical trials are warranted to verify this assumption. Notably, the optimal treatment regime for non-adrenergic vasopressors with respect to compound, dose, and timing still needs to be defined.
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Best Pract Res Clin Anaesthesiol · Dec 2016
ReviewHaemodynamic coherence - The relevance of fluid therapy.
The ultimate goal of fluid therapy is to improve the oxygenation of cells by improving the cardiac output, thus improving microcirculation by optimizing macrocirculation. This haemodynamic coherence is often altered in patients with haemorrhagic shock and sepsis. The loss of haemodynamic coherence is associated with adverse outcomes. ⋯ Monitoring microcirculation and haemodynamic coherence may be an additional tool to predict the response to fluid administration. In addition, microcirculatory analysis may support the clinician in his decision to not administer fluids when microcirculatory blood flow is preserved. In future, the indication, guidance and termination of fluid therapy may be assessed by bedside microvascular analysis in combination with standard haemodynamic monitoring.
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Best Pract Res Clin Anaesthesiol · Sep 2016
ReviewAcute aortic syndrome: A systems approach to a time-critical disease.
Acute aortic syndrome represents a group of potentially lethal aortic diseases, including classic acute aortic dissection, intramural hematoma, and penetrating atherosclerotic aortic ulcer. Among these conditions, type A aortic dissection is the most common acute presentation. ⋯ Recently, several new system-based approaches, such as implementation of multidisciplinary experienced high-volume centers and establishment of regional systematic management flow have been reported to improve the outcome. Here, we will describe the pathophysiology, diagnosis, and treatment as well as the new systematic approach to treat acute aortic syndrome.