Active and Passive Changes in the Characteristic Impedance of the Proximal Aorta
It has been shown earlier that volume expansion causes a change in the activity of the aortic smooth muscle (Dujardin et al., 1980a). After increasing the circulating blood volume by 30%, the aortic diameter D at a given pressure P (e.g. 125 kdyne/cm2) was increased by 6.6% while dP/dD was decreased by 14.6%. Using formula (1), which relates the characteristic impedance of the proximal aorta (ZC) to the aortic P-D relationship, a decrease in ZC at a given pressure would be predicted (ρ is the density of the blood).
KeywordsVolume Expansion Characteristic Impedance Aortic Pressure Flow Probe Circulate Blood Volume
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