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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the continuous monitoring of splanchnic organ oxygen saturation (SpO2) would make the early detection of inadequate tissue oxygenation feasible, reducing the risk of hypoperfusion, severe ischemia, multiple organ failure, and, ultimately, death. In an attempt to create a splanchnic SpO2 sensor that can be used intra-operatively, pre-operatively and post-operatively this paper describes the design and technical evaluation of fiber optic based reflectance pulse oximeter sensor and processing system. In a detailed investigation to determine the optimal source-emitter spacing it was found that the optimum separation distance was between 3mm and 6mm. In vivo thermal testing showed that the rise in temperature at the tip of the fiber at both wavelengths was insignificant and therefore should have no effect in the splanchnic tissue.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2007
Local control of temperature in a theoretical human model of selective brain cooling.
A method of feedback control of local brain temperature during therapeutic intracarotid cold saline infusion is presented and tested on a theoretical cerebral heat transfer model based on the Pennes bioheat equation. In this temperature control method, the infusion rate of cold saline is varied based on the rate of temperature change, and the deviation of temperature to a target, within a voxel in the treated region of brain. ⋯ Two hours of treatment decreased the required inflow of ice-cold saline from 30 ml/min to 21 and 7 ml/min in the non-ice and ice cases, respectively. Intracarotid hematocrit had higher values in the non-ice case.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2007
The role of intracarotid cold saline infusion on a theoretical brain model incorporating the circle of willis and cerebral venous return.
This study describes a theoretical model of brain cooling by intracarotid cold saline infusion which takes into account redistribution of cold perfusate through the circle of Willis (CoW) and cold venous return (VR) from the head. This model is developed in spherical coordinates on a four tissue layer hemispherical geometrical configuration. Temperature evolution is modeled according to the Pennes bioheat transfer equation. ⋯ The temperature effect in the CoW model was present but less robust in the ipsilateral anterior region, as final temperature was 32 degrees C. However, cooling was also achieved in contralateral and posterior brain regions. This model continues to demonstrate the feasibility of intracarotid cold saline infusion for ischemic stroke therapy.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2007
A simple and efficient algorithm with a coarse to fine approach for arterial beat pulse detection.
This paper presents a simple algorithm for arterial beat pulse detection. It consists in a coarse to fine approach : the first step is performed with a lifting Haar wavelet transform with thresholding and provides search intervals, the second step is to localize the beat pulse in the original signal within these areas. Thanks to online available database, the performance of this algorithm can be compared to others and its ability to detect peaks is sufficient considering its low amount of calculation.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2007
Automatic identification of spike-wave events and non-convulsive seizures with a reduced set of electrodes.
Epileptiform activity in the brain, whether localized or generalized, constitutes an important category of abnormal electroencephalogram (EEG). Seizures are episodes of relatively brief disturbances of mental, motor or sensory activity caused by paroxysmal cerebral activity. They are not always accompanied by the characteristic convulsions that we commonly associate with the word epilepsy. ⋯ The proposed signal processing algorithm is based on the detection of spike-wave events obtained from a wavelet analysis of the EEG signal, combined with an analysis of the complexity of the EEG using fractal dimension estimates. We show that this algorithm has excellent sensitivity and specificity. In particular, the fractal analysis is a key factor in the removal of falsely detected spike-wave events (false positives) that can be caused by voluntary or involuntary artifacts such as fast eyelid flutter.