mean circulatory filling pressure

Mean circulatory filling pressure, venous return curve, and Guyton's graphical analysis are basic concepts in cardiovascular physiology. However, some medical students may not know how to view and interpret or understand them adequately. To deepen students' understanding of the graphical analysis, in place of having to perform live animal experiments, we developed an interactive cardiovascular simulator, as a self-learning tool, as a web application. The minimum closed-loop model consisted of a ventricle, an artery, resistance, and a vein, excluding venous resistance...

BACKGROUND: The mesenteric venous reservoir plays a vital role in mediating blood volume and pressure changes and is richly innervated by sympathetic nerves; however, the precise nature of venous sympathetic regulation and its role during hypertension remains unclear. We hypothesized that sympathetic drive to mesenteric veins in spontaneously hypertensive (SH) rats is raised, increasing mean circulatory filling pressure (MCFP), and impairing mesenteric capacitance. METHODS: Arterial pressure, central venous pressure, mesenteric arterial, and venous blood flow were measured simultaneously in conscious male Wistar and SH rats...

The three pathophysiologic contributors to septic shock include varying combinations of hypovolemia (relative > absolute), decreased vascular tone or vasoplegia, and myocardial dysfunction. The three pillars of hemodynamic support include fluid boluses, vasopressors with or without inotrope infusions. The three end-points of hemodynamic resuscitation include an adequate cardiac output (CO), adequate mean arterial pressure (MAP) and diastolic blood pressure (DBP) for organ perfusion, and avoiding congestion (worse filling) parameters...

BACKGROUND: Acute myocardial infarction complicated by cardiogenic shock (AMI-CS) is associated with significant morbidity and mortality. Mechanical circulatory support (MCS) devices increase systemic blood pressure and end organ perfusion while reducing cardiac filling pressures. METHODS AND RESULTS: The National Cardiogenic Shock Initiative (NCT03677180) is a single-arm, multicenter study. The purpose of this study was to assess the feasibility and effectiveness of utilizing early MCS with Impella in patients presenting with AMI-CS...

BACKGROUND: Pulmonary arterial hypertension (PAH) is characterized by persistently increased pressure in the pulmonary arteries. New defining criteria for the different hemodynamic types of pulmonary hypertension (PH) that occur with left heart disease have been proposed by the task force on PH. After consideration of the changes in the general definition of PH in left heart disease, the proposed hemodynamic definition was: (1) isolated postcapillary PH: pulmonary artery wedge pressure >15 mm Hg and mean pulmonary arterial pressure (mPAP) >20 mm Hg and pulmonary vascular resistance (PVR) <3 Woods units (WU); and (2) combined post- and precapillary PH: pulmonary artery wedge pressure >15 mm Hg, mPAP >20 mm Hg, and PVR ≥3 WU...

BACKGROUND: The main aim of the study was to investigate the behaviours of the mean systemic filling pressure (Pmsf ), calculated by the mathematical method, and its derived variables of venous return after volume expansion (VE) and passive leg raising (PLR), with analysis according to fluid and PLR responsiveness. METHODS: This was a post-hoc analysis of a multicentre prospective study. We included 202 mechanically ventilated patients with acute circulatory failure...

We propose a simple, intuitive model to progressively explain the principles underlying venous return. At stop-flow, mean circulatory filling pressure (MCFP) can be defined by the filling of the cardiovascular system from internal and external environments, blood vessel compliance, and oncotic pressure. The dynamic distribution of blood within a regular cardiac system and the establishment of central venous pressure (CVP) and mean arterial pressure (MAP) can then be explained by cardiac output and factors controlling distribution...

BACKGROUND: Evaluation of the venous system has long been underestimated as an important component of the circulatory system. As systemic venous pressure increases, the perfusion pressure to the tissues is compromised. During initial resuscitation in cardiac surgery, excessive fluid administration is associated with increased morbidity and mortality. METHODS: We conducted a cross-sectional study of 60 consecutive adult patients who underwent cardiac surgery and in whom it was possible to obtain the venous excess ultrasound (VExUS) grading system and mean systemic filling pressure (Pmsf) in the postoperative period upon admission, at 24 and 48 h...

Echocardiography can assess cardiac preload when fluid administration is used to treat acute circulatory failure. Changes in stroke volume (SV) are inherently a continuous phenomenon relating to the pressure gradient for venous return (VRdP). However, most clinical studies have applied a binary definition based on a fractional change in SV. This study tested the hypothesis that calculating the analog mean systemic filling pressure (Pmsa ) and VRdP would enhance echocardiography to describe SV responses to a preload challenge...

Septic shock is a common condition associated with hypotension and organ dysfunction. It is associated with high mortality rates of up to 60% despite the best recommended resuscitation strategies in international guidelines. Patients with septic shock generally have a Mean Arterial Pressure below 65 mmHg and hypotension is the most important determinant of mortality among this group of patients. The extent and duration of hypotension are important. The two initial options that we have are 1) administration of intravenous (IV) fluids and 2) vasopressors, The current recommendation of the Surviving Sepsis Campaign guidelines to administer 30 ml/kg fluid cannot be applied to all patients...

BACKGROUND: Dissociation between macrocirculation and microcirculation is often observed in surgical patients. OBJECTIVE: To test the hypothesis that the analogue of mean circulatory filling pressure (Pmca) can monitor hemodynamic coherence during major non-cardiac surgery. METHODS: In this post-hoc analysis and proof-of-concept study, we used the central venous pressure (CVP), mean arterial pressure (MAP), and cardiac output (CO) to calculate Pmca...

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Background: A decade ago, it became possible to derive mean systemic filling pressure (MSFP) at the bedside using the inspiratory hold maneuver. MSFP has the potential to help guide hemodynamic care, but the estimation is not yet implemented in common clinical practice. In this study, we assessed the ability of MSFP, vascular compliance (Csys), and stressed volume (Vs) to track fluid boluses. Second, we assessed the feasibility of implementation of MSFP in the intensive care unit (ICU). Exploratory, a potential difference in MSFP response between colloids and crystalloids was assessed...

The essential role of the endothelium in vascular homeostasis is associated with the release of endothelium-dependent relaxing and contractile factors (EDRF and EDCF, respectively). Different from arteries, where these factors are widely studied, the vasoactive factors derived from the venous endothelium have been given less attention. There is evidence for a role of the nitric oxide (NO), endothelium-dependent hyperpolarization (EDH) mechanism, and cyclooxygenase (COX)-derived metabolites as EDRFs; while the EDCFs need to be better evaluated since no consensus has been reached about their identity in venous vessels...

Objective: Fontan circulation maintains preload and cardiac output by reducing venous capacitance and increasing central venous pressure (CVP). The resultant congestive end-organ damage affects patient prognosis. Therefore, a better circulatory management strategy to ameliorate organ congestion is required in patients with Fontan circulation. We sought to verify whether aggressive arterial and venous dilation therapy in addition to pulmonary dilation (super-Fontan strategy) can improve Fontan circulation and reduce congestion...

BACKGROUND: Despite current resuscitation strategies, circulatory shock and organ injury after cardiac surgery occur in 25-40% of patients. Goal-directed resuscitation after cardiac surgery has generated significant interest, but clinical practice to normalize hemodynamic variables including mean arterial pressure, cardiac filling pressures, and cardiac output may not reverse microcirculation abnormalities and do not address cellular dysoxia. Recent advances in technology have made it possible to measure critical components of oxygen delivery and oxygen utilization systems in live human tissues and blood cells...

The characteristics of physiologic hemodynamic coherence are not well-investigated. We examined the physiological relationship between circulating blood volume, sublingual microcirculatory perfusion, and tissue oxygenation in anesthetized individuals with steady-state physiology. We assessed the correlation of mean circulatory filling pressure analogue (Pmca) with sublingual microcirculatory perfusion and red blood cell (RBC) velocity using SDF+ imaging and a modified optical flow-based algorithm. We also reconstructed the 2D microvessels and applied computational fluid dynamics (CFD) to evaluate the correlation of Pmca and RBC velocity with the obtained pressure and velocity fields in microvessels from CFD (pressure difference, (Δp))...

BACKGROUND: Low cardiac output is the main cause of perioperative death after pericardiectomy for constrictive pericarditis. We investigated the associated risk factors and consequences. METHODS: We selected constrictive pericarditis patients undergoing isolated pericardiectomy from January 2013 to January 2021. Postoperative low cardiac output was defined as requiring mechanical circulatory support or more than one inotrope to maintain a cardiac index > 2.2 L •min-1 •m-2 without hypoperfusion, despite adequate filling status...

Distinct populations of stretch-sensitive mechanoreceptors attached to myelinated vagal afferents are found in the heart and adjoining coronary and pulmonary circulations. Receptors at atrial-vein junctions appear to be involved in control of intravascular volume. These atrial receptors influence sympathetic control of the heart and kidney but contribute little to reflex control of systemic vascular resistance. Baroreceptors at the origins of the coronary circulation elicit reflex vasodilatation, like feedback control from systemic arterial baroreceptors, as well as having characteristics that could contribute to regulation of mean pressure...

Windkessel function is governed by conductance artery compliance that is associated with cardiovascular disease in adults independently of other risk factors. Sex-related differences in conductance artery compliance partly explain the sex-related differences in risk of cardiovascular disease. Studies on sex-related differences in conductance artery function in prepubertal children are few and inconclusive. This study determined the conductance artery compliance and cardiac function by magnetic resonance imaging in 150 healthy children (75 girls) aged 7-10 yr...