The Windkessel model enlarges his applicativity on the whole circulatory dynamics studies. Then, the lumped parameter models allow global representation of blood flow circulation. In the vascular tree, peripheral branches are terminated by a resistance term representing smaller vessels. Blood flow and pressure are expressed by the intensity of current and voltage in an electrical analogue based...

A windkessel model was applied on a beat-to-beat basis to evaluate the arterial mechanical characteristics in seven conscious rats. Ascending aortic arterial pressure (AP) and blood flow were recorded during steady-state in basal conditions, during infusions of isoprenaline, sodium nitroprusside, and phenylephrine, and after intravenous atenolol injection. For each cardiac cycle the exponential...

JONES, DAVID R., B. LOWELL LANGILLE, DAVID J. RANDALL, AND GRAHAM SHELTON. BloodJEow in the dorsal and ventral aortas of the cod, Gadus morhua. Am. J. Physiol. 226(l) : 90-95. 1974.Dorsal and ventral aortic blood flows have been recorded in cod and the flows compared with results from hydraulic and electrical models of the fish circulatory system. In the hydraulic model increase in “dorsal aort...

The passive mechanical properties of the dorsal aorta and the vena cava of Octopus vulgaris were investigated in vitro. Both vessels are highly distensible structures that exhibit non-linear elasticity, but have substantially different material properties. The volume compliance of each vessel is maximal within the resting physiological pressure range (2-3 kPa in the aorta and 0-0.5 kPa in the v...

Cardiac output (CO) and stroke volume (SV) are the key hemodynamic parameters to be monitored and assessed in ambulatory and critically ill patients. The purpose of this study was to introduce and validate a new algorithm to continuously estimate, within a proportionality constant, CO and SV by means of mathematical analysis of peripheral arterial blood pressure (ABP) waveforms. The algorithm c...

OBJECTIVES Prosthetic replacement of the thoracic aorta with common Dacron prostheses impairs the aortic 'windkessel' and, in valve-sparing procedures, also aortic valve function. Elastic graft material may overcome these deficiencies. METHODS Fresh porcine aortas including the root were set up in a mock circulation before and after replacement of the ascending part with a novel vascular pros...

Computer simulations of bypass hemodynamics can provide a valuable insight into the problem of graft failures, considering the close relationship between the hemodynamics and the patency and overall performance of implanted bypass grafts. However, to be able to reliably predict flow changes brought about by implanted bypass grafts, numerical simulations have to be carried out for physiologicall...