A Study of the Use of EEG Analysis to Evaluate the Depth of Anesthesia Using Bispectrum Analysis Method / 대한마취과학회지

BACKGROUND:In this study, a distribute characteristics on the bispectral coupling of EEG were examined according to the depth of anesthesia by using bispectum analysis a type of nonlinear signal processing. METHODS: 25 patients during the general anesthesia were studied. In the preprocess, base line correction and linear detrend was used. During the awakening state, preoperatively and postoperatively, appearance rate of bispectral coupling was observed that a strong appearance rate was represented in major frequency zone such as (15, 15) Hz but weak appearance rate investigated in the other minor frequency zone. Whilst anesthetized, a strong appearance rate revealed the low frequency range below (10, 10) Hz and a weak appearance rate viewed in the other frequency range. As such was compared with the delta ratio and spectrum edge frequency (SEF). RESULTS: The delta ratio showed significantly lower values at induction (3.60 +/- 0.98) and during the maintenance (5.0+/-1.74) of anaesthesia than preoperatively (10.30 +/- 2.44) and postoperatively (13.03 +/- 2.29)(P < 0.05). These results were consistent with the trend of delta ratio, namely that the index of evaluation for the depth of anesthesia, known as the reflex of the conscious level of patient's during anesthesia. While these results were not consistent with SEF analysis results that the index of evaluation for suppression level of patient's during recovery stage of anesthesia. SEF shows lower values at maintenance (17.00 +/- 1.22) and postoperatively (12.20 +/- 1.53) than preoperatively (22.50 +/- 1.75) and at the induction (22.40 +/- 1.18) of anesthesia(P < 0.05). CONCLUSIONS: The bispectrum analysis method provided useful information about the index of evaluation according to the level of unconsciousness and suppression among other evaluation factor on depth of anesthesia.

Simulation of the Cardiovascular System Using PID Control Model / 대한의료정보학회지

OBJECTIVE: The electric analog circuit model can be used to analyse the various function of the cardio vascular system and the dynamic characteristics on each part of human body. According to the previous studies, viscous resistance, flow inertia, and vascular compliance in the cardiovascular system are analogous to resistance, inductance, and capacitance in electric circuit, so the cardiovascular system models have been represented by the electric circuit models. These approaches were to propose suitable models for the interested part of body and to simulate the various characteristics on the cardiovascular system. METHODS: This paper tried to put the characteristics of morphologic structure into the suggested electric circuit model. After setting parameter values of the model the dynamic characteristics of the cardio vascular system is simulated using VisSim, which is one of the simulation tools. RESULTS: The derived simulation results have represented major cardiovascular functions of normal adults. Also simulation results reflect the variation due to the pathophysiological state. CONCLUSION: The controller by baroreceptor, which is one of controllers to control the cardiovascular system, is appended in the model. The dynamic response characteristics and the procedure to restore blood pressure to normal state was observed by simulation lasted a certain period of bleeding.