Response of the Cardiovascular System to Vibration and Combined Stresses
Abstract
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 dp/dt and heart rate. The animal preparation was further refined to include A/V nodal ablation to permit manipulation of heart rate (30 to 300 b/min) 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 ACM's of AFTI type aircraft. A summary of major results is presented.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 30, 1982
- Accession Number
- ADA125225
Entities
People
- Charles F. Knapp
- David C. Randall
- Joyce M. Evans
Organizations
- University of Kentucky