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 2009
Critiquing treatment and setting ventilatory parameters by using physiological modeling.
A modeling system is presented that can be used to predict the effects of ventilatory settings on the blood gases of patients on mechanical ventilation. The system uses a physiological model of the patient that includes lungs, body tissue, and brain tissue compartments. The model includes the effects of changes in the cardiac output and cerebral blood flow and lung mechanical factors. The system has applications in critiquing different treatment options and can be used alone or in combination with decision support systems to set ventilatory parameters and optimize treatment for patients on mechanical ventilation.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2009
In-vivo evaluation of a fiber-optic splanchnic photoplethysmographic sensor during open laparotomy.
There is a need for a reliable and continuous monitoring of abdominal organ oxygen saturation (SpO(2)). Splanchnic ischemia may ultimately lead to cellular hypoxia and necrosis and may well contribute to the development of multiple organ failures and increased mortality. A new prototype reflectance fiber optic photoplethysmographic sensor and signal processing system was evaluated on six anaesthetized patients undergoing elective laparotomy. ⋯ The normalized amplitudes of the splanchnic PPG signals were in good agreement with those obtained from the periphery using an identical fiber optic sensor. Furthermore, average SpO(2) values were in good agreement and showed correlation with those obtained from a commercial system. These preliminary results suggest that a miniaturized 'indwelling' fiber optic sensor may be a suitable method for pre-operative and post-operative evaluation of splanchnic organ SpO(2) and their health.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2009
Pulse rate analysis in case of central sleep apnea: a new algorithm for cardiac rate estimation.
This paper first describes the AM-FM demodulation of an arterial pressure signal. Although it is known to be efficient on signals modulated by breathing, we demonstrate that in case of lack of respiratory modulation (real or simulated central sleep apnea), the AM-FM algorithm doesn't perform well in heart rate extraction. ⋯ The error for cardiac frequency estimation is around 0.2 BPM (Beats Per Minute) versus 5.5 BPM for the AM-FM demodulation. Further experimentations will be performed (with this time both cardiac and respiratory assessments) and will deal with real sleep apnea cases.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2009
Detection of respiratory rhythm from photoplethysmographic signal by adaptive morphological filter.
An approach using morphological filter technique is proposed to determine the respiratory rhythm from the photoplethysmographic (PPG) signal. As the structuring elements of morphological filter have a decisive effect on the analysis result, in the study the structuring elements are determined by the individual heart rate adaptively. ⋯ Furthermore, the low computational complexity of the algorithm may make it easy to be implemented on Microprogrammed Control Units (MCU) for real-time processing. More experimental data is necessary to improve the reliability and robustness of the algorithm.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2009
Estimation of the aortic pressure waveform from a radial artery pressure waveform via an adaptive transfer function: Feasibility demonstration in swine.
We previously proposed a new technique to estimate the physiologically and clinically more relevant central aortic pressure (AP) waveform from a conveniently and safely measured peripheral artery pressure (PAP) waveform distorted by wave reflections. In contrast to conventional generalized transfer function (GTF) techniques, the technique is able to adapt the transfer function relating PAP to AP to the inter-patient and temporal variability of the arterial tree by defining it through a tube model and invoking the fact that aortic flow is negligible during diastole to estimate the unknown model parameters. We conducted feasibility testing of this adaptive transfer function technique here with respect to radial artery pressure (RAP) waveforms, for the first time, as well as femoral artery pressure (FAP) waveforms from four swine instrumented with AP catheters during several hemodynamic conditions. Our results showed that the AP waveforms estimated by the technique from the RAP and FAP waveforms were in superior agreement to the measured AP waveforms (overall respective errors of 4.1 and 4.8 mmHg) than the two unprocessed PAP waveforms (9.1 and 8.1 mmHg) and a previous GTF technique trained on a subset of the same data (5.0 and 5.8 mmHg).