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
Fuzzy control for closed-loop, patient-specific hypnosis in intraoperative patients: a simulation study.
Research has demonstrated the efficacy of closed-loop control of anesthesia using bispectral index (BIS) as the controlled variable, and the recent development of model-based, patient-adaptive systems has considerably improved anesthetic control. To further explore the use of model-based control in anesthesia, we investigated the application of fuzzy control in the delivery of patient-specific propofol-induced hypnosis. In simulated intraoperative patients, the fuzzy controller demonstrated clinically acceptable performance, suggesting that further study is warranted.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2009
Long-term assessment of post-cardiac-arrest neurological outcomes with somatosensory evoked potential in rats.
Cardiac arrest (CA) can produce complex changes in somatosensory evoked potentials (SSEPs). Somatosensory evoked potentials (SSEPs) indicate the intactness of somatosensory pathways and are commonly used for brain function monitoring during surgeries. Multiresolution biorthogonal wavelet analysis was applied to SSEPs recorded during established CA experiments and post-CA long-term recovery periods in rats. ⋯ In the long-term recovery period (within 72 hours), both the amplitudes of SSEPs and the interpeak latencies returned to the baseline. Our results suggest that the changes of SSEPs may represent the post-CA neurological injuries and recovery in the somatosensory afferent pathways. The results here lay ground work for establishing the relationship between SSEPs and post-CA neurological injuries and functional outcomes as well as deploying SSEP in clinical settings to monitor patients resuscitated from CA in the future.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2009
Estimating transition point of anesthetic-induced loss of consciousness in mice by detecting motion in response to forced movement.
To characterize transition periods of entrance to and emergence from anesthetic-induced unconsciousness in terms of thalamocortical neural activity, we devised a new method estimating a transition point of anesthetic-induced loss of consciousness. The method continuously monitors an animal's head motion in response to forced movement on treadmill and uses the motion signals as a criterion of the transition. ⋯ Resulting signals from the motion detector could discriminate the points of entrance into and emergence from the anesthetic-induced unconsciousness with resolution corresponding to the sampling frequency. This method makes it possible to track the anesthetic transition period continuously without contaminating EEGs and LFPs.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2009
A wavelet based method for steady-state detection in anesthesia.
With the recent concern on patient's outcome following general anesthesia, automatic control of drugs has been a field of interest. The Bispectral Index (BIS) is an EEG based hypnosis monitor, in current use at the operating theatre as a guiding tool for the anesthesiologist to titrate drugs, and prevent awareness. ⋯ A steady-state index was obtained using a wavelet analysis technique for trend detection. This tool may be used in the future to model the drug's combined effect on the hypnosis indices, and also to bring some insight on disturbances not related to drug changes.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2009
Randomized Controlled TrialEffect of remifentanil on the nonlinear electroencephalographic entropy parameters in propofol anesthesia.
Nonlinear electroencephalographic entropy parameters have been proposed for the assessment of depth of anesthesia. The influence of remifentanil, a commonly used intraoperative opioid, on these parameters, namely approximate entropy (ApEn), sample entropy (SampEn), and permutation entropy (PeEn), during induction of propofol anesthesia was studied. ⋯ No consistent influence on PeEn was observed. However, this may have been due to strong interindividual variation in PeEn values.