Biomedizinische Technik. Biomedical engineering
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A new generation of EU research is expected to take life at the end of 2002. One of the new elements of the Sixth Framework Programme (FP6), which is essential for the realisation of the European Research Area (ERA), will be the use of new instruments for funding research, such as Integrated Projects (IP) and Networks of Excellence (NoE). Integrated Projects will contribute to strengthening European competitiveness and solve major societal problems, by mobilising a critical mass of research and development resources and skills existing in Europe. Networks of Excellence will contribute to strengthening European scientific and technological excellence though a better integration of research capacities across Europe.
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In this paper we present the medical augmented reality system INPRES for Intraoperative Presentation of surgical planning and simulation results. The system is based on a see-through head-mounted display for data visualization and overlay. ⋯ Further tasks are detection of occlusions, intuitive man-machine-cooperation and evaluation of the complete setup. The system configuration and the methods are shown, first results are given and future work is outlined.
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Approximate entropy, a measure of regularity, can be used to analyze the electroencephalogram of patients in general anesthesia to discriminate between different states of consciousness. EEG burst suppression patterns reflect a state of deep anesthesia. ⋯ Possible solutions to this problem may be limited by the demand of computing power for entropy calculation and the reaction time following changes in patient state. Different approaches for an online monitoring application are examined.
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During extracorporeal circulation, many important circulatory parameters are unknown, being inaccessible for measuring probes, as e.g. the perfusion of the brain. An observer system, which estimates such patient variables continuously throughout the operation, can extend the information basis for the decisions of the perfusionist regarding the control of the heart-lung machine and thus contribute to adjust this operation procedure to the actual patient situation. ⋯ Beside the classical Luenberger observer design, a rule-based approach has been tested, which is also based on the structure of a Luenberger observer, however instead of an observer matrix a correction algorithm has been used in the feedback loop. A prototype of this system for animal experimental and clinical evaluation has been realised.
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Supplying organs and body tissues with sufficient oxygen is one of the most important vital human functions. Commercial pulse oximeters compute the functional oxygen saturation from relative values (reduced hemoglobin and oxyhemoglobin). Methemoglobin (MetHb) and carboxyhemoglobin (COHb) are not taken into account, since they are considered to be reduced hemoglobin and oxyhemoglobin (RHb, HbO2). ⋯ In this work, a non-invasive pulse oximeter is developed, which finds the entire hemoglobin concentration photometrically, and measures the fractional oxygen saturation and pulse rate. The signal of transmitted light I is processed according to the Lambert-Beer-law. The signal decays exponentially with the thickness d of the irradiated sample and its absorption coefficient alpha (I = I0 e -alpha d), where I0 is the incident light intensity.