; THE PHYSIOLOGICAL BASIS FOR ASSESSMENT OF HAEMODYNAMIC PARAMETERS BY MEANS OF ARTERIAL PRESSURE PULSE WAVEFORM...

The aim of the study was elaboration of an approach for monitoring of cardiac output (CO) and systemic arterial pressure (SAP) using data obtained via measurements of the pulse waveform in peripheral arteries under steady-state and transitive conditions. CO and SAP were simultaneously recorded in common carotid and femoral arteries in narcotized (urethane, 1 mg/g) rats continuously and after infusions of sodium nitroprusside, adrenaline hydrochloride, dextran solution or acute experimental hemorrhage. Fourier analysis has been employed for estimating the generalized transfer functions (GTFs) and generalized vascular input impedance (GVI) along with individualized transfer functions (ITFs) for the states in the aftermath of infusions of vasoactive pharmacological agents, dextran solution or acute experimental hemorrhage. The results of pulse waveform analysis in the femoral artery were used for reconstruction of the pulse curves in carotid arteries and aortic blood flow. A comparison of directly measured and predicted pressure and flow values revealed the absence of significant differences under steady-state conditions. Short-term shifts of haemodynamics that follow various transitory influences on the cardiovascular system inevitably evoke changes in the mechanical properties of the blood vessels. Since both GTF and ITF express the mechanical properties of the vascular bed, their values also change under these conditions. This causes control of vascular stiffness and rigidity by estimation of the pulse wave velocities before and after administration of vasoactive agents and/or changes of the circulation blood volume.