Response of the Cardiovascular System to Vibration and Combined Stresses
Final rept. 1 Oct 1979-30 Sep 1982
KENTUCKY UNIV LEXINGTON WENNER-GREN RESEARCH LAB
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During the three year grant period, efforts were focused on the relative contribution of cardiac in addition to peripheral vascular mechanisms to the frequency response characteristics of integrated cardiovascular regulation during time-dependent acceleration stress. To this end, our chronically instrumented animal preparation was enhanced to include cardiac denervation. In these animals, ultrasonic dimension crystals were also added for measuring left ventricular major and minor axis, wall thickness and calculated volume. This is in addition to instrumentation for measuring aortic flow, left and right ventricular and aortic arch pressures, cardiac output, peripheral resistance, stroke volume, max dpdt and heart rate. The animal preparation was further refined to include AV nodal ablation to permit manipulation of heart rate 30 to 300 bmin via a microprocessor controlled, opened or closed loop system. Closed loop control can be achieved between heart rate and a measured variable or combinations of variables such as arterial pressure, acceleration etc. A separate study was also conducted to investigate the differences between cardiovascular responses to and - Gy acceleration vectors as well as combinations of Gy and Gz loadings. This study was initiated because of a lack of information concerning cardiovascular responses to Gy loadings and various G blends anticipated from the ACMs of AFTI type aircraft. A summary of major results is presented.
- Anatomy and Physiology
- Stress Physiology