Time of dissociation between microcirculation, macrocirculation, and lactate levels in a rabbit model of early endotoxemic shock

Effects of Local Vasodilators and the Autonomic Nervous System on Microcirculation and Mitochondrial Function in Septic Rats

Systemic vasodilating agents like nitroglycerin (NG) or iloprost (Ilo) show beneficial effects on intestinal microcirculation during sepsis, which could be attenuated by activation of the sympathetic nervous system or systemic side effects of vasodilating agents. This exploratory study aimed to investigate the effects of topically administered vasodilators and the parasympathetic drug carbachol on colonic microcirculatory oxygenation (µHbO2), blood flow (µFlow) and mitochondrial respiration. A total of 120 male Wistar rats were randomly assigned to twelve groups and underwent either colon ascendens stent peritonitis (CASP) or sham surgery. After 24 h, animals received the following therapeutic regimes: (1) balanced full electrolyte solution, (2) carbachol, (3) NG, (4) Ilo, (5) NG + carbachol, and (6) Ilo + carbachol. Mitochondrial respiration was measured in colon homogenates by respirometry. In sham animals, NG (-13.1%*) and Ilo (-10.5%*) led to a decrease in µHbO2. Additional application of carbachol abolished this effect (NG + carbachol: -4.0%, non-significant; Ilo + carbachol: -1.4%, non-significant). In sepsis, carbachol reduced µHbO2 when applied alone (-10.5%*) or in combination with NG (-17.6%*). Thus, the direction and degree of this effect depend on the initial pathophysiologic condition.

Research progress on microcirculatory disorders in septic shock: A narrative review

Hemodynamic coherence plays a critical role in the outcomes of septic shock. Due to the potential negative consequences of microcirculatory disorders on organ failure and clinical outcomes, the maintenance of a balance between the macrocirculation and microcirculation is a topic of significant research focus. Although physical methods and specialized imaging techniques are used in clinical practice to assess microcirculation, the use of monitoring devices is not widespread. The integration of microcirculation research tools into clinical practice poses a significant challenge for the future. Consequently, this review aims to evaluate the impact of septic shock on the microcirculation, the methods used to monitor the microcirculation and highlight the importance of microcirculation in the treatment of critically ill patients. In addition, it proposes an evaluation framework that integrates microcirculation monitoring with macrocirculatory parameters. The optimal approach should encompass dynamic, multiparametric, individualized, and continuous monitoring of both the macrocirculation and microcirculation, particularly in cases of hemodynamic separation.

Modeling sepsis, with a special focus on large animal models of porcine peritonitis and bacteremia

Infectious diseases, which often result in deadly sepsis or septic shock, represent a major global health problem. For understanding the pathophysiology of sepsis and developing new treatment strategies, reliable and clinically relevant animal models of the disease are necessary. In this review, two large animal (porcine) models of sepsis induced by either peritonitis or bacteremia are introduced and their strong and weak points are discussed in the context of clinical relevance and other animal models of sepsis, with a special focus on cardiovascular and immune systems, experimental design, and monitoring. Especially for testing new therapeutic strategies, the large animal (porcine) models represent a more clinically relevant alternative to small animal models, and the findings obtained in small animal (transgenic) models should be verified in these clinically relevant large animal models before translation to the clinical level.

Endothelial Activation and Microcirculatory Disorders in Sepsis

The vascular endothelium is crucial for the maintenance of vascular homeostasis. Moreover, in sepsis, endothelial cells can acquire new properties and actively participate in the host's response. If endothelial activation is mostly necessary and efficient in eliminating a pathogen, an exaggerated and maladaptive reaction leads to severe microcirculatory damage. The microcirculatory disorders in sepsis are well known to be associated with poor outcome. Better recognition of microcirculatory alteration is therefore essential to identify patients with the worse outcomes and to guide therapeutic interventions. In this review, we will discuss the main features of endothelial activation and dysfunction in sepsis, its assessment at the bedside, and the main advances in microcirculatory resuscitation.