Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference
-
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.
-
Conf Proc IEEE Eng Med Biol Soc · Jan 2007
Cuffless and noninvasive measurement of systolic blood pressure, diastolic blood pressure, mean arterial pressure and pulse pressure using radial artery tonometry pressure sensor with concept of Korean traditional medicine.
Parameters for noninvasive diagnosis and monitoring of cardiovascular disease. We developed a new method to measure blood pressure (BP) noninvasively without cuff. In Korean traditional medicine, the degree of the pulse depth is one of the important criteria to diagnosis. ⋯ According to the American National Standard for Electronic or Automated Sphygmomanometers, the mean difference (MD) should be +/- 5mmHg or less with a standard deviation (SD) of +/- 8mmHg or less. Hence, the results of MAP and PP were within the limits for the AAMI SP 10 criteria and the results of SBP and DBP were not within the limits for the AAMI SP 10 criteria. The preliminary results indicate the results are quite reliable and promising.
-
Conf Proc IEEE Eng Med Biol Soc · Jan 2007
The complete electrode model for imaging and electrode contact compensation in electrical impedance tomography.
Electrical Impedance Tomography (EIT) is an imaging modality which currently shows promise for the detection and characterization of breast cancer. A very significant problem in EIT imaging is the proper modeling of the interface between the body and the electrodes. We have found empirically that it is very difficult, in a clinical setting, to assure that all electrodes make satisfactory contact with the body. ⋯ To compensate for these problems, we have developed a hybrid nonlinear-linear reconstruction algorithm in which we first estimate electrode surface impedances, using a Newton-type iterative optimization procedure with an analytically computed Jacobian matrix. We subsequently make use of a linearized algorithm to perform a three-dimensional reconstruction of perturbations in both contact impedances and in the spatial distributions of conductivity and permittivity. Results show that, using this procedure, artifacts due to electrodes making poor contact can be greatly reduced.
-
Conf Proc IEEE Eng Med Biol Soc · Jan 2007
Real-time evaluation of patient monitoring algorithms for critical care at the bedside.
Rapid interpretation of physiological time-series data and accurate assessment of patient state are crucial to patient monitoring in critical care. Algorithms that use artificial intelligence techniques have the potential to help achieve these tasks, but their development requires well-annotated patient data. ⋯ The alarm annotations in real time at the bedside indicate that about 89% of these alarms were clinically-relevant true positives; 6% were true positives without clinical relevance; and 5% were false positives. These findings show an improved specificity of the alarm algorithms in the newer generation of bedside monitoring systems and demonstrate that the designed data acquisition system enables real-time evaluation of patient monitoring algorithms for critical care.
-
Conf Proc IEEE Eng Med Biol Soc · Jan 2007
Estimation of effects of visually-induced motion sickness using independent component analysis.
To quantify the effect of visually-induced motion sickness on the autonomic nervous system, the authors previously proposed a new physiological index rho max representing the maximum cross-correlation coefficient between blood pressure variability and heart rate variability whose frequency components are limited to the Mayer wave band. However, rho max requires measurement of continuous blood pressure with an expensive and bulky measuring device. In the present study, an easier method for obtaining rho max with measurement of neither continuous blood pressure nor ECG but using finger photoplethysmography (PPG) only has been developed. ⋯ Two experiments in which subjects performed the Valsalva maneuver and then they watched a swaying video image were carried out to evaluate the adequacy of the proposed method. The experimental results have shown that the proposed method worked successfully as good as the conventional method. This means that the proposed method can contribute to increase in the number of subjects because multiple subjects can be used even in a single experiment.