Many astronauts cannot stand up after landing due to orthostatic intolerance, the inability to maintain adequate blood pressure. Dr. Roger G. Mark is designing and evaluating a computational model of the cardiovascular system that accounts for this behavior in response to sudden orthostatic stress such as standing up. The model will be used to evaluate the physiological hypotheses for orthostatic intolerance, to integrate the multiple effects of space flight and to predict countermeasure effectiveness.
Computational Models of the Cardiovascular System and its Response to Microgravity and Disease
Roger G. Mark, M.D., Ph.D.
Massachusetts Institute of Technology
Harvard-MIT Division of Health Sciences and Technology
The primary objectives of this project are to develop a general, modular model of cardiovascular function that contains the essential features associated with the effects of gravity, and to use this model to examine the short term effects of changes in posture before and after exposure to the microgravity environment. The objective of the currently funded project was to extend a previously developed computational model of the cardiovascular system and to use this model to investigate the short-term (0--5 mins) beat-to-beat hemodynamic response of the cardiovascular system to abrupt orthostatic stress --- such as head-up tilt (HUT) or lower body negative pressure (LBNP). The project aimed at facilitating the understanding of the physiology and treatment (prevention) of orthostatic intolerance in post-flight astronauts.
We proposed to:
- Enhance the current version of the cardiovascular simulation to better represent the short-term effects of abrupt orthostatic stress;
- Verify the model and use it to investigate and evaluate various hypotheses of orthostatic intolerance, and predict the effects of countermeasures, requiring extensive collection and archiving of experimental data from collaborators;
- Complete, document, and disseminate to other investigators a form of the model implemented in JAVA, and;
- Apply the cardiovascular model to the clinical problem of intelligent patient monitoring with particular emphasis on establishing an enhanced research database of multiparameter hemodynamic data from intensive care patients.