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 2007
Randomized Controlled TrialA new method for evaluating the performance of depth-of-hypnosis indices - the D-value.
An alternative statistic, the D-value, is presented for the evaluation of the performance of EEG-based depth-of-hypnosis measures against the Observers' Assessment of Alertness/Sedation scale. The measures considered here are spectral entropy, approximate entropy, Lempel-Ziv complexity and Higuchi fractal dimension. The study is based on recordings from 45 patients, divided into three groups of 15 recordings each. ⋯ All the patients received stepwise increased dose of propofol. The study shows that the D-value is a promising and flexible statistic for the evaluation of the discriminative power of the EEG measures with respect to the OAA/S scale. The D-value indicates well the dependence of the performance of the measures on the EEG frequency band as well as on remifentanil concentration.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2007
Optimizing the tactile display of physiological information: vibro-tactile vs. electro-tactile stimulation, and forearm or wrist location.
Anesthesiologists use physiological data monitoring systems with visual and auditory displays of information to monitor patients in the operating room (OR). The efficacy of visual-audio systems may impose an increase in patient risk when the demand for constant switching of attention between the patient and the visual monitoring system is high. This is evidenced by auditory alarms frequently being neglected in a noisy OR environment. ⋯ A post-study questionnaire was completed by each subject to assess the comfort and usability of the three prototypes. We found that both VF and VW were superior to the EF in both accuracy and comfort and, that there were no differences between the wrist and the forearm. In conclusion, the tactile-display prototypes designed to alert the clinician of adverse changes in a patient's physiological state efficaciously and unobtrusively delivered these data and warranted further investigation and development.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2007
EEG frequency progression during induction of anesthesia: from start of infusion to onset of burst suppression pattern.
The anesthetic infusion with propofol influences EEG activity rather smoothly by changing the amplitude activity in different frequency bands. This results in a frequency progression pattern (FPP) which can be related to the depth of anesthesia. ⋯ The results reveal the underlying FPP and how the onset of the BSP is related to it. The proposed method offers potential for the development of automatic assessment systems for the depth of anesthesia.
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Conf Proc IEEE Eng Med Biol Soc · Jan 2007
Comparison of cardiac output monitoring methods for detecting central hypovolemia due to lower body negative pressure.
Reduction in mean arterial pressure (MAP) is a late indictor of progressive circulatory pathology. Non-invasive monitoring methods that are superior indicators of circulatory compromise would be clinically valuable. With IRB approval, 21 healthy volunteers were subjected to progressive lower body negative pressure (LBNP) until the onset of presyncopal symptoms. ⋯ In terms of discriminating between (a) the 11 subjects who tolerated the protocol (i.e., tolerated higher levels of LBNP); versus (b) the 10 non-tolerant subjects, there was also a significant difference between MF and LTI: the ROC AUC for MF was 0.40 and for LTI was 0.66. There were no significant differences between MF nor EBI, however. In conclusion, LTI is notable as the only method which (a) correlated with decompression: (b) distinguished between decompression to -45 mmHg versus recovery; and (c) distinguished between those subjects who adequately compensated for central hypovolemia (tolerant) and those who did not have such robust physiologic compensation (non-tolerant).
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Conf Proc IEEE Eng Med Biol Soc · Jan 2007
Screening device for identification of patients with paroxysmal atrial fibrillation to prevent ischemic strokes.
The most frequently occurring cardiac arrhythmia in the adulthood is atrial fibrillation. In Germany, the number of sick people is estimated at 800,000. Patients who suffer from atrial fibrillation often do not sense any symptoms of the illness. ⋯ These persons must be recognized, because of their increased stroke risk in order to be able to attend it. In this work, the chest strap CorBelt, developed by the company Corscience GmbH&Co. KG, is equipped with an algorithm for the recognition of atrial fibrillation with the aid of heart rate variability.