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Venous return is the flow of blood from the systemic venous network towards the right heart. At steady state, venous return equals cardiac output, as the venous and arterial systems operate in series. However, unlike the arterial one, the venous network is a capacitive system with a high compliance. It includes a part of unstressed blood, which is a reservoir that can be recruited via ...
Graphically it results in a leftward shift of the volume–pressure relationship of the vasculature (upper left). This shifts the venous return curve to the right and increases cardiac output through the Starling mechanism (lower left). This effect is identical to giving volume to expand stressed volume.
Venous return is the blood flow crossing both venae cavae. According to Poiseuille’s law, it is determined by the resistance to venous return (RVr), and by the pressure gradient between the downstream pressure, i.e. RAP, and the upstream pressure, which is Pmsf (Fig. 1): Venous return = (Pmsf − RAP)/RVr.
The sensitivity of systemic venous return to respiratory-induced changes has been described in the classic experiments by Guyton and colleagues [22, 23]. The basic principle is that systemic venous return is the major determinant of circulation and is equal to left ventricular output under steady state conditions [7, 24, 25]. Guyton et al.
Recent studies challenge the utility of central venous pressure monitoring as a surrogate for cardiac preload. Starting with Starling’s original studies on the regulation of cardiac output, this review traces the history of the experiments that elucidated the role of central venous pressure in circulatory physiology. Central venous pressure is an important physiologic parameter, but it is ...
Introduction The aim of this study was to assess how mean systemic pressure (Psm) and resistance to venous return (Rvr) behave during passive leg raising (PLR) in cases of fluid responsiveness and fluid unresponsiveness. Method In 30 patients with an acute circulatory failure, in order to estimate the venous return curve, we constructed the regression line between pairs of cardiac index (CI ...
CVP is the downstream pressure of the systemic venous return and then acts on organ perfusion and function. Chen et al. [ 7 ] reported that admission CVP was associated with increased risk of acute kidney injury in critically ill patients with an Odds ratio of 1.02 [1.00–1.03] for every cmH 2 O increase.
Venous return and cardiac output depend on mean circulatory filling pressure. To investigate the effect of MCFP and P RA on venous return, Guyton and colleagues cannulated the right atria of 15 anesthetized dogs. This cannula was attached to a motorized pump, and the output cannula was placed in the proximal aorta.
Arthur C. Guyton's studies on venous return curves, which involved altering right atrial pressure (Pra) through an artificial shunt, provided significant insights into physiology but did not fully encompass the complexities of cardiovascular function, particularly how venous return is intricately linked to cardiac function . Brengelmann ...
Central venous pressure (CVP) is a local hemodynamic parameter determined by the interaction between venous return and cardiac function and used as a surrogate of intravascular volume . Therefore, CVP measurements are often applied for assessing volume status and volume responsiveness to guide fluid resuscitation at the bedside in critically ...