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
EEG spectral changes and onset of burst suppression pattern in propofol/remifentanil anesthesia.
This paper studies how remifentanil, a commonly used intraoperative opioid, affects the relation of the onset of burst suppression pattern (BSP) and the spectral changes of EEG during anesthesia. The onsets of BSP were detected using both manual and the automatic method proposed from the EEGs of twenty-seven patients who had received different amount of remifentanil with the anesthetic. ⋯ The results showed that remifentanil significantly affects the relation of EEG spectral changes and the onset of BSP. The finding is important since the current EEG-based assessment of the depth of anesthesia basically relies on the analysis of the spectral features and BSP.
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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
Predicting ICU hemodynamic instability using continuous multiparameter trends.
Identifying hemodynamically unstable patients in a timely fashion in intensive care units (ICUs) is crucial because it can lead to earlier interventions and thus to potentially better patient outcomes. Current alert algorithms are typically limited to detecting dangerous conditions only after they have occurred and suffer from high false alert rates. Our objective was to predict hemodynamic instability at least two hours before a major clinical intervention (e.g., vasopressor administration), while maintaining a low false alert rate. ⋯ Area under receiver-operating curve (ROC) 0.83+/-0.03, sensitivity 0.75+/-0.06, and specificity 0.80+/-0.07; if the specificity is targeted at 0.90, then the sensitivity is 0.57+/-0.07. Based on our preliminary results, we conclude that the algorithms we developed using HR and BP trend data may provide a promising perspective toward reliable predictive alerts for hemodynamically unstable patients.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2008
Monitoring retroperitoneal bleeding model of piglets by electrical impedance tomography.
To investigate continuous monitoring capacity of electrical impedance tomography (EIT) for retroperitoneal bleeding, studies were carried out on six anesthetized piglet's bleeding model produced by injecting anticoagulated blood into renal region. For each subject, total blood of about 200 ml was injected within time periods ranging from tens of minutes to several hours. ⋯ EIT images were reconstructed by dynamic back-projection algorithm. The results showed that impedance changes caused by bleeding could be revealed by EIT images.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2008
Predict the neurological recovery under hypothermia after cardiac arrest using C0 complexity measure of EEG signals.
Clinical trials have proven the efficacy of therapeutic hypothermia in improving the functional outcome after cardiac arrest (CA) compared with the normothermic controls. Experimental researches also demonstrated quantitative electroencephalogram (qEEG) analysis was associated with the long-term outcome of the therapeutic hypothermia in brain injury. Nevertheless, qEEG has not been able to provide a prediction earlier than 6h after the return of spontaneous circulation (ROSC). ⋯ Significantly greater C0 complexity was found in hypothermic group than that in normothermic group as early as 4h after the ROSC (P0.05). C0 complexity at 4h correlated well with the 72h neurodeficit score (NDS) (Pearson's correlation = 0.882). The results showed that the C0 complexity could be an early predictor of the long-term neurological recovery from cardiac arrest.