Cerebral Perfusion During Acceleration Stress

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Authors
  1. Walsh, C.
  2. Cirovic, S.
Corporate Authors
Defence and Civil Inst of Environmental Medicine, Downsview ONT (CAN);Ryerson Polytechnical Inst, Toronto ONT (CAN)
Abstract
In this contract we developed experimental, theoretical and computational simulations of the effect of Gz on cerebral perfusion. The long term goal is to develop a quantitative model of cardiovascular response to the orthostatic sresses experienced in aerial combat. The model will be used in the design and testing of advanced life support systms. The work comprises two main components: - Theoretical, experimental, and computational studies were used to validate the open loop, mean blood flow model developed in the previous contract (Phase I). - The closed loop time simulation was extended to include nonlinear wall mechanics, positive pressure breathing (PPB), and a preliminary baroreflex model. A linear wave theory shows that the cerebrospinal fluid has a negligible effect on cranial pulse poropagation. A mechanical experiment gives a strong quantitative validation of the open loop, mean blood flow model in Phase I. Further validation of that model is provided by running the current unsteady simulation on the open cerebral flow loop. Finally, the cerebral flow loop is incorporated into a closed loop network with scheduled variations in Gz, G-suit effect, and PPB. These results all confirm that collapse of jugular vein is the prinicipal factor causing low cerebral bloow flow, and that PPB improves cerebral blood flow by opening the jugulvar vein. TRUNCATED
Keywords
Cerebral perfusion
Report Number
DCIEM-CR-2000-022 — Contract Report
Date of publication
07 Dec 1999
Number of Pages
127
DSTKIM No
CA001637
CANDIS No
513536
Format(s):
Hardcopy;Document Image stored on Optical Disk

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