The influence of esmolol on right ventricular function in early experimental endotoxic shock

Beta-blockers in septic shock: What is new?

The use of beta(β)-blockers during septic shock aimed at countering peripheral adrenergic stress may be justified by the early reduction in deleterious effects resulting from sympathetic overactivation, and could improve the prognosis of patients in septic shock. Animal studies have demonstrated either a maintenance or increase in cardiac output (CO) despite the decrease in heart rate (HR) associated with improved myocardial performance. The mechanism by which β-blockers alter hemodynamics in septic shock is debated; however, preclinical and clinical data show that β-blockers are safe when started at a low dose. Recent publications (2019-2021) on adrenergic β1 receptor antagonists used in septic shock indicate that esmolol and landiolol should not be used in the early phase. While there is no optimal timing for their administration, a minimum of 12 h after the initiation of vasopressor therapy in stabilized euvolemic patients is a reasonable option. Patients should have a normal cardiac function, although a slight depression is compatible with landiolol use under hemodynamic monitoring. Slow titration in patients who remain tachycardic is preferable to rapid titration. When used to decrease HR, landiolol is also effective in reducing the incidence of new arrhythmias. Results of a well-performed and well-powered randomized controlled trial (RCT) demonstrating a positive effect on survival - or at least on hard surrogates such as the incidence/duration of organ failure - are pending.

Hemodynamic Influences on Mesenteric Blood Flow in Shock Conditions

The gastrointestinal (GI) system, is most vulnerable to hypoperfusion among the splanchnic organs. Disturbed perfusion of the mesenteric area may lead to GI dysfunction, cause further injury to the patients and even vital outcomes. However, due to the limitation of detection methods, the hemodynamic influences on mesenteric blood flow in clinical practice are not fully understood. By elucidating the underlying mechanisms, we may be able to recognize disturbed GI perfusion and eventually GI dysfunction at an early phase. Thus, in this review, we will focus on situations where mesenteric blood flow is disturbed due to hemodynamic causes in shock conditions, and the present research status will be discussed. English language articles published before 2020 were identified through a computerized PubMed search using the terms "mesenteric, gastrointestinal, intestinal, splanchnic, blood flow, perfusion" and the cofactors. Relevant publications were retrieved and scanned for additional sources. There were few clinical trials focusing on mesenteric blood flow in shock patients. Most were animal experiments. Based on the best current evidence from these sources, we described the major influences on mesenteric blood flow in the context of physiologic accommodation, disease-related effects and the consequences of medical interventions related to shock conditions. During circulatory shock, sepsis, and medical interventions related to shock treatment, mesenteric blood flow changes and shows different features. We need to carefully consider these issues when making medical decisions, and more work needs to be done on early detection of GI hypoperfusion and its accurate correlation with GI dysfunction.

β-Blockade attenuates renal blood flow in experimental endotoxic shock by reducing perfusion pressure

Clinical data suggests that heart rate (HR) control with selective β1-blockers may improve cardiac function during septic shock. However, it seems counterintuitive to start β-blocker infusion in a shock state when organ blood flow is already low or insufficient. Therefore, we studied the effects of HR control with esmolol, an ultrashort- acting β1-selective adrenoceptor antagonist, on renal blood flow (RBF) and renal autoregulation during early septic shock. In 10 healthy sheep, sepsis was induced by continuous i.v. administration of lipopolysaccharide, while maintained under anesthesia and mechanically ventilated. After successful resuscitation of the septic shock with fluids and vasoactive drugs, esmolol was infused to reduce HR with 30% and was stopped 30-min after reaching this target. Arterial and venous pressures, and RBF were recorded continuously. Renal autoregulation was evaluated by the response in RBF to renal perfusion pressure (RPP) in both the time domain and frequency domain. During septic shock, β-blockade with esmolol significantly increased the pressure dependency of RBF to RPP. Stopping esmolol showed the reversibility of the impaired renal autoregulation. Showing that clinical diligence and caution are necessary when treating septic shock with esmolol in the acute phase since esmolol reduced RPP to critical values thereby significantly reducing RBF.

Hemodynamic response to β-blockers in severe sepsis and septic shock: A review of current literature

The administration of β-blockers in patients with sepsis is a trending topic in intensive care medicine since the landmark study by Morelli and colleagues, showing a striking decrease in 28-day mortality compared to standard care. While the available evidence suggests that the use of β-blockers in septic shock is safe, the effects on hemodynamics are controversial. In this paper, we review the effect of β-blockade in septic shock on hemodynamics from animal models to critically ill patients.