A CARDIOVASCULAR DYNAMIC RESPONSE INDEX
Abstract
Human tolerances to accelerating forces long have been recognized as being dependent on the magnitude, direction, and duration of a given G. Experimentally derived tolerance curves for positive G have been reported by Stoll and Kydd. The former provides the time (time at peak pulse rise time) at which a given end-point (PLL) will occur for various sustained G levels while the latter provides the period of haversine shaped G profile which will produce the same end-point for various peak G's. Aerodynamically derived G profiles take on a wide variety of shapes and forms. Using a lumped parameter description for both the arterial and venous portions of the cardiovascular system, a simplified mathematical model has been derived which includes a feedback loop for changes in cardiac output and peripheral vascular resistance to represent the non-linear effects of cardiovascular reflexes. The model, which describes the transient and steady state response of the system to any shaped G profile, has been programmed on an analog computer. By identifying a particular response of the system to correspond with a given endpoint (PLL), a cardiovascular dynamic response index (CDRI) HAS BEEN DEFINED5 By using the CDRI, the model provides agreement with both the Stoll and Kydd tolerance curves.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 26, 1970
- Accession Number
- AD0708383
Entities
People
- Carl T. Reichwein
- Emma Fessenden
- Richard J. Crosbie
Organizations
- Naval Air Warfare Center Warminster