Development of an in-vitro circulatory system with known resistance and capacitance.

An in-vitro (hydrodynamic) model of the circulatory system was developed. The model consisted of a pump, compliant tubing, and valves for resistance. The model is used to simulate aortic pressure and flow.

Review of non-invasive techniques of measuring aortic pressure through the use of ultrasound.

Aortic pressure is a hemodynamic property that is needed for analysis of the cardiovascular system. Current aortic pressure techniques involve the use of invasive methods and insertion of foreign objects into the body which may cause infections, diseases, and other clinical manifestations. Therefore, a non-invasive method of measuring aortic pressure both clinically and experimentally is needed.

The ventriculo-arterial coupling ratio during transient Gz events.

It has been shown by Westerhof et al. that the ratio tau/T (where tau = Rp*SAC and Rp is total peripheral resistance, SAC is systemic arterial compliance, and T is heart period) is approximately a constant in all mammals under resting conditions such that diastolic pressure is sufficiently high to assure adequate coronary perfusion. The aim of this study is to determine if the ratio tau/T is constant under the transient condition of a rapid onset rate +Gz acceleration.