Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference
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Conf Proc IEEE Eng Med Biol Soc · Jan 2004
A comprehensive physiological model of circulation enables automatic piloting of hemodynamics in patients with acute heart failure.
A comprehensive physiological model of the whole circulation is mandatory to quantitatively diagnose pathophysiology and to guide an appropriate treatment. Such a model would enable automatic piloting of hemodynamics in patients with acute heart failure. By extending Guyton's model, so as to deal with heart failure predominantly affecting left heart and to quantify left atrial pressure, we constructed such a model consisting of a venous return (VR) surface and a cardiac output (CO) curve. ⋯ Using these, we could accurately predict CO (y = 0.93x + 6.5, r2 = 0.96, Figure 2), P(RA) (y = 0.87x + 0.4, r2 = 0.91) and P(LA) (y = 0.90x + 0.48, r2 = 0.93). Our comprehensive physiological model of circulation is useful in accurately predicting hemodynamics from the measurement of a single set of CO, P(RA) and (P(LA) following blood volume changes. Therefore, this model enables continuous monitoring of blood volume and pump performance for automatic hemodynamic piloting.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2004
Continuous blood pressure monitoring during exercise using pulse wave transit time measurement.
This paper gives an overview of a research, which is focused on the development of the convenient device for continuous non-invasive monitoring of arterial blood pressure. The blood pressure estimation method is based on a presumption that there is a singular relationship between the pulse wave propagation time in arterial system and blood pressure. The parameter used in this study is pulse wave transit time (PWTT). ⋯ The reliability of beat to beat systolic blood pressure calculation during physical exercise was the main focus for the current paper. Sixty-one subjects (healthy and hypertensive) were studied with the bicycle exercise test. As a result of current study it is shown that with the correct personal calibration it is possible to estimate the beat to beat systolic arterial blood pressure during the exercise with comparable accuracy to conventional noninvasive methods.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2004
Accurate derivation of heart rate variability signal for detection of sleep disordered breathing in children.
The electrocardiogram (ECG) signal is used extensively as a low cost diagnostic tool to provide information concerning the heart's state of health. Accurate determination of the QRS complex, in particular, reliable detection of the R wave peak, is essential in computer based ECG analysis. ECG data from Physionet's Sleep-Apnea database were used to develop, test, and validate a robust heart rate variability (HRV) signal derivation algorithm. ⋯ All signal processing algorithms were implemented in MATLAB. We present a description of the EHT algorithm and analyze pilot data for eight children undergoing nocturnal polysomnography. The pilot data demonstrated that the EHT method provides an accurate way of deriving the HRV signal and plays an important role in extraction of reliable measures to distinguish between periods of normal and sleep disordered breathing (SDB) in children.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2004
Cardiac output monitoring in intensive care patients by radial artery pressure waveform analysis.
We have developed a novel technique for monitoring cardiac output (CO) changes by mathematically analyzing a single peripheral arterial blood pressure (ABP) waveform. In contrast to all previous techniques, our technique analyzes the ABP waveform over time scales greater than a cardiac cycle in which complex wave reflections are attenuated. ⋯ We report an overall error in the technique of 18.1% with respect to the error-prone clinical thermodilution measurements. This study promotes thorough future testing of the technique in humans.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2004
Physiologically-based minimal model of agitation-sedation dynamics.
Agitation-sedation cycling in critically ill patients, characterized by oscillations between states of agitation and over-sedation, damages patient health and increases length of stay and cost. The model presented captures the essential dynamics of the agitation-sedation system, is physiologically representative, and is validated by accurately simulating patient response for 37 critical care patients. The model provides a platform to develop and test controllers that offer the potential of improved agitation management.