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 2008
Target controlled infusion for kids: trials and simulations.
Target controlled infusion (TCI) for Kids is a computer controlled system designed to administer propofol for general anesthesia. A controller establishes infusion rates required to achieve a specified concentration at the drug's effect site (C(e)) by implementing a continuously updated pharmacokinetic-pharmacodymanic model. This manuscript provides an overview of the system's design, preclinical tests, and a clinical pilot study. ⋯ Predicted C(e) values during standard clinical practice, the accuracy of wake-up times predicted by the system, and potential correlations between patient wake-up times, C(e), and state entropy (SE) were assessed. Neither Ce nor SE was a reliable predictor of wake-up time in children, but the small sample size of this study does not fully accommodate the noted variation in children's response to propofol. A C(e) value of 1.9 mug/ml was found to best predict emergence from anesthesia in children.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2008
A new approach to reconstruction of central aortic blood pressure using 'adaptive' transfer function.
This paper presents a new system identification approach to the reconstruction of central aortic blood pressure signal by exploiting a non-invasive peripheral blood pressure measurement. This technique, which is called the 'adaptive' transfer function, is able to reconstruct the aortic blood pressure signal by characterizing the aortic-to-peripheral cardiovascular dynamics solely based on the peripheral measurement. In contrast to the previous related efforts, it does not require any a priori knowledge on the empirical and/or population-based relationship, e.g. the predetermined or generalized transfer function, as well as multiple peripheral measurements. The initial proof-of-principle on the efficacy of the adaptive transfer function is demonstrated by the experimental results from human and animal subjects.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2008
Autonomic nervous system response to vibrating and electrical stimuli on the forearm and wrist.
In today's operating rooms, anesthesiologists use physiological data monitoring systems with visual and auditory cues to receive patient information. The efficacy of these visual-audio systems is limited by the human limitations of these modalities. Previous studies have shown the potential use of a complementary, or alternate, patient data monitoring technology utilizing another psychophysically relevant modality: the sense of touch via vibro-tactile or electro-tactile stimulation. ⋯ Using the LifeShirt, system, electrocardiogram (ECG), respiratory rate (Br), tidal volume (Vt) data were collected. Results showed a higher value of the heart rate and heart rate variability (HRV) when using the VF compared to the VW and EF. We also found that the HRV response for the three tactile prototypes was correlated with the accuracy of tactile pattern identification.
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Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) contribute to the morbidity and mortality of intensive care patients worldwide, and have large associated human and financial costs. We identified a reference data set of 624 mechanically-ventilated patients in the MIMIC-II intensive care database with and without low PaO(2)/FiO(2) ratios (termed respiratory instability), and developed prediction algorithms for distinguishing these patients prior to the critical event. In the end, we had four rule sets using mean airway pressure, plateau pressure, total respiratory rate and oxygen saturation (SpO(2)), where the specificity/sensitivity rates were either 80%/60% or 90%/50%.
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Listening and interpreting lung sounds by a stethoscope had been an important component of screening and diagnosing lung diseases. However this practice has always been vulnerable to poor audibility, inter-observer variations (between different physicians) and poor reproducibility. ⋯ The proposed algorithm integrates and analyses the set of parameters based on ATS (American Thoracic Society) definition of wheezes. It is very robust, computationally simple and yielded sensitivity of 84% and specificity of 86%.