The responses of cerebral (pial) arterioles to increased venous pressure were examined in anesthetized cats equipped with cranial windows for the observation of the cerebral microcirculation. Increased venous pressure was induced by occlusion of the superior vena cava. Intracranial pressure was kept constant. Increased venous pressure when the window was filled with stationary cerebrospinal flu...

The responses of cerebral (pial) arterioles to increased venous pressure were examined in anesthetized cats equipped with cranial windows for the observation of the cerebral microcirculation. Increased venous pressure was induced by occlusion of the superior vena cava. Intracranial pressure was kept constant. Increased venous pressure when the window was filled with stationary cerebrospinal flu...

Based on observations that as cardiac output (as determined by an artificial pump) was experimentally increased the right atrial pressure decreased, Arthur Guyton and coworkers proposed an interpretation that right atrial pressure represents a back pressure restricting venous return (equal to cardiac output in steady state). The idea that right atrial pressure is a back pressure limiting cardia...

In order to establish the nature of the stretch-evoked dynamic properties of vascular smooth muscle in arterioles, we have examined the static and dynamic effects of both arterial pulse pressure and elevated venous pressure on the resistance vessels (arteries and arterioles) in an intestinal mesenteric preparation derived from dogs. The dynamic myogenic response to stretch stimuli was directly ...

With the subject in the right lateral decubitus position, changes of central venous pressure can be recorded accurately and conveniently from a vein in the antecubital fossa of the dependent arm. Theoretically the hydrostatic pressure transforms the venous bed between the heart and the site of puncture into uninterrupted wide channels with relatively low distensibility. Simultaneous recordings ...

Compared with arterial hemodynamics, there has been relatively little study of venous hemodynamics. We propose that the venous system behaves just like the arterial system: waves propagate on a time-varying reservoir, the windkessel, which functions as the reverse of the arterial windkessel. During later diastole, pressure increases exponentially to approach an asymptotic value as inflow contin...

OBJECTIVE To assess the pressure and flow velocity relations and respiratory variability of the systemic venous and hepatic venous return in patients with univentricular circulation. PATIENTS 15 selected patients who had undergone cavopulmonary anastomosis (10) or atriopulmonary anastomosis (5). Mean age at operation was 55.1 months (range 9 to 145). Studies were done at 75.5 (32.6) months (m...

Stenosis of either the portal or splenic vein increases splenic afferent nerve activity (SANA), which, through the splenorenal reflex, reduces renal blood flow. Because these maneuvers not only raise splenic venous pressure but also reduce splenic venous outflow, the question remained as to whether it is increased intrasplenic postcapillary pressure and/or reduced intrasplenic blood flow, which...

Vacuum-assisted venous drainage (VAVD) is frequently used to increase venous return through smaller venous cannula and reduced venous line size. The purpose of this study is to determine the maximal flow rates achieved through various venous cannula with varying amounts of negative pressure applied during VAVD. The first test circuit consisted of 25 different venous cannulae connected to 3/8 in...

hemodynamic monitoring is needed in up to 58% of patients presented to the emergency department. central venous pressure (cvp) monitoring is generally useful to assess general volume status. there are several methods of cvp measurement, which can be categorized as invasive and non-invasive. cvp manometer and electronic transducer are among the invasive methods and direct observation, ultrasonog...