The hypothesis in this dissertation is that the mathematical and physiological models can be developed to estimate cardiac output and metabolic demand of exercising individual from simple non-invasive physiological parameters such as heart rate, respiration, working rate and body movement (using multiple triaxial accelerometers). The models developed could be incorporated as part of a closed loop control system for cardiac pacemaker and/or heart assist devices. A reliable measurement system has been developed to measure cardiac output, heart rate, body movement and respiratory variables and to process and analyze the data coming from the measurements. Analyzing, designing and modelling of the measurement system have also been conducted. The foremost is to model the mixing chamber based gas measurement system and the other is to analyze and compensate the orientation error of triaxial accelerometers on the assessment of energy expenditure. Two mathematical models and one physiological model have been developed in the current research. The first mathematical model is to estimate steady state energy expenditure using a nonlinear regression method from the outputs of triaxial accelerometers. Results show that the proposed nonlinear model is better than both the traditional linear models and the earlier nonlinear models. The second mathematical model emphasizes on investigating the key central cardiovascular response to the steady state of incremental exercise. The modeling results show that all the studied cardiovascular parameters response to exercise nonlinearly except heart rate which responses to exercise linearly. Furthermore, based on a previous model developed in the Biomedical Systems Laboratories in UNSW and the reliable experimental data, a physiological model has been established to successfully estimate both the cardiac output and the metabolic demand with heart rate and workload as its input.
| Identifer | oai:union.ndltd.org:ADTP/258333 |
| Date | January 2007 |
| Creators | Wang, Lu, Electrical Engineering & Telecommunications, Faculty of Engineering, UNSW |
| Publisher | Awarded by:University of New South Wales. Electrical Engineering & Telecommunications |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | Copyright Wang Lu., http://unsworks.unsw.edu.au/copyright |
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