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Current Opinion in Anaesthesiology Apr 2022Advances in the treatment of septic shock have historically focused on resuscitation endpoints, mainly mean arterial pressure and cardiac output. As the definitions of... (Review)
Review
PURPOSE OF REVIEW
Advances in the treatment of septic shock have historically focused on resuscitation endpoints, mainly mean arterial pressure and cardiac output. As the definitions of sepsis and septic shock have shifted to focus on the diversity of causes of dysregulated host-response we have seen an emerging phenotype where tissue hypoxia persists despite adequate macrocirculatory parameters. Interest in the topic of microcirculation is re-emerging as validated bedside techniques for hemodynamic monitoring, such as video microscopes, are becoming available. We review the current understanding of how sepsis induced hypoperfusion with a focus on recent advances in monitoring the microcirculation, and how a proliferation of biomarkers and emerging therapeutic targets may impact future research.
RECENT FINDINGS
Conventional hemodynamic monitoring systems fail to assess the microcirculation, and it's response to treatment. Lactate and venous oxygen saturations often drive biomarker-guided sepsis management. Visual assessments such as mottling and capillary refill time are often associated with predicting outcomes, but sometimes can have issues with inter-provider reliability. Microcirculatory damage can be observed sublingually and appears to have prognostic value.
SUMMARY
Sepsis is associated with changes in the microcirculation that can lead to tissue hypoxia and organ dysfunction. Further studies are needed to validate the usefulness of microcirculatory bedside tools in guiding resuscitative efforts.
Topics: Hemodynamics; Humans; Microcirculation; Reproducibility of Results; Resuscitation; Sepsis; Shock, Septic
PubMed: 35081058
DOI: 10.1097/ACO.0000000000001098 -
Nature Reviews. Gastroenterology &... Apr 2019The liver microcirculatory milieu, mainly composed of liver sinusoidal endothelial cells (LSECs), hepatic stellate cells (HSCs) and hepatic macrophages, has an essential... (Review)
Review
The liver microcirculatory milieu, mainly composed of liver sinusoidal endothelial cells (LSECs), hepatic stellate cells (HSCs) and hepatic macrophages, has an essential role in liver homeostasis, including in preserving hepatocyte function, regulating the vascular tone and controlling inflammation. Liver microcirculatory dysfunction is one of the key mechanisms that promotes the progression of chronic liver disease (also termed cirrhosis) and the development of its major clinical complication, portal hypertension. In the present Review, we describe the current knowledge of liver microcirculatory dysfunction in cirrhotic portal hypertension and appraise the preclinical models used to study the liver circulation. We also provide a comprehensive summary of the promising therapeutic options to target the liver microvasculature in cirrhosis.
Topics: Combined Modality Therapy; Humans; Hypertension, Portal; Liver Circulation; Microcirculation; Vascular Resistance
PubMed: 30568278
DOI: 10.1038/s41575-018-0097-3 -
Critical Care (London, England) 2015This article presents a personal viewpoint of the shortcoming of conventional hemodynamic resuscitation procedures in achieving organ perfusion and tissue oxygenation...
This article presents a personal viewpoint of the shortcoming of conventional hemodynamic resuscitation procedures in achieving organ perfusion and tissue oxygenation following conditions of shock and cardiovascular compromise, and why it is important to monitor the microcirculation in such conditions. The article emphasizes that if resuscitation procedures are based on the correction of systemic variables, there must be coherence between the macrocirculation and microcirculation if systemic hemodynamic-driven resuscitation procedures are to be effective in correcting organ perfusion and oxygenation. However, in conditions of inflammation and infection, which often accompany states of shock, vascular regulation and compensatory mechanisms needed to sustain hemodynamic coherence are lost, and the regional circulation and microcirculation remain in shock. We identify four types of microcirculatory alterations underlying the loss of hemodynamic coherence: type 1, heterogeneous microcirculatory flow; type 2, reduced capillary density induced by hemodilution and anemia; type 3, microcirculatory flow reduction caused by vasoconstriction or tamponade; and type 4, tissue edema. These microcirculatory alterations can be observed at the bedside using direct visualization of the sublingual microcirculation with hand-held vital microscopes. Each of these alterations results in oxygen delivery limitation to the tissue cells despite the presence of normalized systemic hemodynamic variables. Based on these concepts, we propose how to optimize the volume of fluid to maximize the oxygen-carrying capacity of the microcirculation to transport oxygen to the tissues.
Topics: Capillaries; Hemodynamics; Humans; Microcirculation; Resuscitation; Shock; Vasoconstriction
PubMed: 26729241
DOI: 10.1186/cc14726 -
Critical Care (London, England) May 2018Adrenaline has been used in the treatment of cardiac arrest for many years. It increases the likelihood of return of spontaneous circulation (ROSC), but some studies... (Review)
Review
Adrenaline has been used in the treatment of cardiac arrest for many years. It increases the likelihood of return of spontaneous circulation (ROSC), but some studies have shown that it impairs cerebral microcirculatory flow. It is possible that better short-term survival comes at the cost of worse long-term outcomes. This narrative review summarises the rationale for using adrenaline, significant studies to date, and ongoing research.
Topics: Epinephrine; Humans; Microcirculation; Propensity Score; Resuscitation; Treatment Outcome
PubMed: 29843791
DOI: 10.1186/s13054-018-2058-1 -
Anesthesia and Analgesia May 2018Colloid solutions have been advocated for use in treating hypovolemia due to their expected effect on improving intravascular retention compared with crystalloid... (Review)
Review
Colloid solutions have been advocated for use in treating hypovolemia due to their expected effect on improving intravascular retention compared with crystalloid solutions. Because the ultimate desired effect of fluid resuscitation is the improvement of microcirculatory perfusion and tissue oxygenation, it is of interest to study the effects of colloids and crystalloids at the level of microcirculation under conditions of shock and fluid resuscitation, and to explore the potential benefits of using colloids in terms of recruiting the microcirculation under conditions of hypovolemia. This article reviews the physiochemical properties of the various types of colloid solutions (eg, gelatin, dextrans, hydroxyethyl starches, and albumin) and the effects that they have under various conditions of hypovolemia in experimental and clinical scenarios.
Topics: Animals; Colloids; Crystalloid Solutions; Fluid Therapy; Humans; Hypovolemia; Microcirculation; Resuscitation
PubMed: 29099424
DOI: 10.1213/ANE.0000000000002620 -
Microcirculation (New York, N.Y. : 1994) Oct 2022
Topics: Microcirculation
PubMed: 36125801
DOI: 10.1111/micc.12785 -
Current Pharmaceutical Design 2018Dyslipidemia is widely accepted as one of the major risk factors in cardiovascular disease mainly due to its contribution in the pathogenesis of atherosclerosis in... (Review)
Review
Dyslipidemia is widely accepted as one of the major risk factors in cardiovascular disease mainly due to its contribution in the pathogenesis of atherosclerosis in medium-sized and large arteries. However, it has become increasingly accepted that high-cholesterol levels can also adversely affect the microvasculature prior to the development of overt atherosclerosis. Moreover, hypercholesterolemia has shown, in preclinical animal models, to exert detrimental effects beyond the vascular tree leading to larger infarcts and adverse cardiac remodeling post-myocardial infarction. At a functional level, hypercholesterolemia has shown to impair endotheliumdependent vasodilation because on defects on nitric oxide bioavailability. The pathogenic mechanisms underlying microvascular dysfunction involve an enhanced arginase activity, enhanced production of free radicals and the activation, recruitment and accumulation of leukocytes, primarily neutrophils, via their diffusion through postcapillary venules. In turn, recruited inflammatory cells and certain inflammatory mediators enhance platelet adhesion, overall inducing a proinflammatory and prothrombotic phenotype. Within the present review, we aim to discuss the existing evidence regarding the presence of dyslipidemia - particularly high low density lipoprotein-cholesterol levels - and the occurrence of microvascular dysfunction, the mechanism by which high cholesterol levels induce functional alterations in the microvascular bed and, finally comment on the impact of dislipidemia-induced microvascular dysfunction at the myocardial level.
Topics: Animals; Dyslipidemias; Humans; Microcirculation
PubMed: 29968532
DOI: 10.2174/1381612824666180702154129 -
Current Opinion in Critical Care Jun 2015Microcirculatory shock is a condition defined by the presence of tissue hypoperfusion despite the normalization of systemic and regional blood flow. In this article, we... (Review)
Review
PURPOSE OF REVIEW
Microcirculatory shock is a condition defined by the presence of tissue hypoperfusion despite the normalization of systemic and regional blood flow. In this article, we discuss the characteristics of the microcirculation in septic shock, the main form of microcirculatory shock, along with its interaction with systemic hemodynamics, and the response to different therapies.
RECENT FINDINGS
In septic shock, microcirculatory abnormalities are common, and more severe in nonsurvivors. In addition, the microcirculation shows a behavior that is frequently dissociated from that of systemic hemodynamics. Therefore, microcirculatory alterations may persist despite correction of systemic hemodynamic variables. Sublingual and intestinal microcirculation might also display divergent behaviors. Moreover, microvascular alterations may improve in response to hemodynamic resuscitation, but the response might depend on the underlying microcirculatory alterations. Particularly, the response to fluids seems to be related to both its basal state and the magnitude of the increase in cardiac output.
SUMMARY
The optimal treatment of microcirculatory shock might require monitoring and therapeutic goals targeted on the microcirculation, more than in systemic variables. The clinical benefits of this approach should be demonstrated in clinical trials.
Topics: Hemodynamics; Humans; Microcirculation; Regional Blood Flow; Resuscitation; Shock, Septic
PubMed: 25827583
DOI: 10.1097/MCC.0000000000000196 -
Microcirculation (New York, N.Y. : 1994) Feb 2019
Topics: Australia; Humans; Microcirculation
PubMed: 30703277
DOI: 10.1111/micc.12533 -
Microcirculation (New York, N.Y. : 1994) Feb 2017Two of the primary risk factors for the progressive evolution of cardiovascular disease are obesity and impaired glycemic control-including both insulin resistance and...
Two of the primary risk factors for the progressive evolution of cardiovascular disease are obesity and impaired glycemic control-including both insulin resistance and overt type 2 diabetes mellitus, leading to increased research emphasis on these conditions, their mechanistic bases, and their health outcomes. This Special Topics Issue of the journal Microcirculation summarizes a symposium at the recent Joint Meeting of the American Physiological Society and the Physiological Society, held in Dublin, Ireland, on July 30, 2016. This symposium, "Adaptive outcomes of microvascular networks to obesity and type 2 diabetes mellitus/insulin resistance," presented four lectures, each of which addressed the larger issue from a different perspective.
Topics: Adaptation, Physiological; Cardiovascular Diseases; Diabetes Mellitus, Type 2; Humans; Insulin Resistance; Microcirculation; Obesity; Societies, Scientific
PubMed: 27987530
DOI: 10.1111/micc.12346