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
Automated beat onset and peak detection algorithm for field-collected photoplethysmograms.
Recent reports suggest that photoplethysmography (PPG), which is a component of routine pulse oximetry, may be useful for detecting hypovolemia. An essential step in extracting and analyzing common PPG features is the robust identification of onset and peak locations of the vascular beats, despite varying beat morphologies and major oscillations in the baseline. Some prior reports used manual analysis of the PPG waveform; however, for systematic widespread use, an automated method is required. ⋯ We validated the algorithm by clinician evaluation of 100 randomly selected PPG waveform samples. For 99% of the beats, the algorithm was able to credibly identify the onsets and peaks of vascular beats, although the precise locations were ambiguous, given the very noisy data from actual clinical operations. The algorithm appears promising, and future consideration of its diagnostic capabilities and limitations is warranted.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2009
Pulse pressure variation estimation using a sequential Monte Carlo method.
We describe a novel automatic algorithm to continuously estimate the pulse pressure variation (PPV) index from arterial blood pressure (ABP) signals. The algorithm utilizes our recently developed sequential Monte Carlo method (SMCM) based on a maximum A-Posterior adaptive marginalized particle filter (MAM-PF). The PPV index is one of most specific and sensitive dynamic indicators of fluid responsiveness in mechanically ventilated patients. We report the assessment results of the proposed algorithm on real ABP signals.
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Nerve localization using peripheral nerve stimulation (PNS) is affected by tissue properties, the anatomy surrounding the nerve, and characteristics of the stimulus waveform. A better understanding of the factors influencing PNS should lead to improved nerve localization techniques for use in regional anesthesia. A finite element approach is described here that includes capacitive effects and accounts for frequency-dependent tissue properties in a computationally efficient manner. The modeling approach can be applied to other bioelectric problems where capacitive effects may be important.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2009
Clinical TrialA hybrid platform based on EOG and EEG signals to restore communication for patients afflicted with progressive motor neuron diseases.
An efficient alternative channel for communication without overt speech and hand movements is important to increase the quality of life for patients suffering from Amiotrophic Lateral Sclerosis or other illnesses that prevent correct limb and facial muscular responses. Often, such diseases leave the ocular movements preserved for a relatively long time. The aim of this study is to present a new approach for the hybrid system which is based on the recognition of electrooculogram (EOG) and electroencephalogram (EEG) measurements for efficient communication and control. ⋯ A comparison of the performance of the EOG-based system has been made with a BCI system that uses P300 waveforms. As a next step, we plan to integrate EOG and EEG sides. The final goal of the project is to realize a unique noninvasive device able to offer the patient the partial restoration of communication and control abilities with EOG and EEG signals.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2009
Noninvasive cardiac output estimation using a novel photoplethysmogram index.
Cardiac output (CO) monitoring is essential for indicating the perfusion status of the human cardiovascular system under different physiological conditions. However, it is currently limited to hospital use due to the need for either skilled operators or big, expensive measurement devices. Therefore, in this paper we devise a new CO indicator which can easily be incorporated into existing wearable devices. ⋯ After least squares linear regression, the precision between CO(imp) and CO estimated from IHAR (CO(IHAR)) was 1.40 L/min. The total percentage error of the results was 16.2%, which was well below the clinical acceptance limit of 30%. The results suggest that IHAR is a promising indicator for wearable and noninvasive CO monitoring.