• The Journal of Internal Korean Medicine
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• v.22 no.2
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• pp.199-205
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• 2001

Background and Purpose : Transcranial doppler ultrasonography(TCD) is a noninvasive and nonradioactive technique for evaluation of the hemodynamics in large cerebral vessels. Sahyangsohap-won(SS) has been considered to be effective for the treatment of various disease, especially cerebrovascular, cardiovascular, and psychosomatoform disorders. But, there is no study about the effect of SS on the cerebral hemodynamics in humans. The aim of this study was to assess the effect of SS on the changes in cerebral hemodynamics and the dose-dependant effect by using TCD. Subjects and Methods : 30 healthy subjects were randomly divided into three group: group 1 took no drug, group 2 took SS one pill, and group 3 took SS 2 pills. Changes in the mean blood flow velocity(MBFV) and pulsatility index(PI) in the middle cerebral artery were evaluated by means of TCD. We obtained hypercapnia with breath-holding and evaluated cerebrovascular reactivity with the breath-holding index(BHI). Systolic blood pressure(SBP), diastolic blood pressure(DBP), and heart rate(HR) were measured by means of ambulatory blood pressure monitoring. In group 2 and group 3, the evaluations were performed during the baseline and were repeated at 20, 40, and 60 minutes after SS administration. In group 1, the evaluation was performed at corresponding time intervals. Results : In mean values of MSFV, PI, SSP, DBP, and HR, no stastically significant differences were found between the 3 groups. However, BHI values were significantly lower in groups 2 and 3 than in group 1 at 40 minutes after SS administration(P<0.05, group 1 vs group 2, group 1 vs group 3 by post-hoc analysis: Scheffe's test) but in dose-dependant effect, there was no difference between group 2 and group 3. Conclusion : These results suggest that SS can decrease vascular resistance in cerebral small arteries or arterioles and enhance their distensibility. Further studies on larger numbers of subjects are needed to confirm these effects and the dose-dependant effects.

• 한국전산유체공학회:학술대회논문집
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• 1999.11a
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• pp.1-6
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• 1999

• 순환기질환의공학회:학술대회논문집
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• 2004.05a
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• pp.28-69
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• 2004

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2941-2946
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• 2007

A model of the cardiovascular system coupling cell, hemodynamics and autonomic nervecontrol function is proposed for analyzing heart mechanics. We developed a comprehensive cardiovascular model with multi-physics and multi-scale characteristics that simulates the physiological events from membrane excitation of a cardiac cell to contraction of the human heart and systemic blood circulation and ultimately to autonomic nerve control. Using this model, we delineatedthe cellular mechanism of heart contractility mediated by nerve control function. To verify the integrated method, we simulated a 10% hemorrhage, which involves cardiac cell mechanics, circulatory hemodynamics, and nerve control function. The computed and experimental results were compared. Using this methodology, the state of cardiac contractility, influenced by diverse properties such as the afterload and nerve control systems, is easily assessed in an integrated manner.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.12
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• pp.1181-1188
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• 2004

This paper reviews the main aspects of cardiovascular system dynamics with emphasis on modeling hemodynamic characteristics using a lumped parameter approach. Methodological and physiological aspects of the circulation dynamics are summarized with the help of existing mathematical models: The main characteristics of the hemodynamic elements, such as the heart and arterial and venous systems, are first described. Lumped models of micro-circulation and pulmonary circulation are introduced. We also discuss the feedback control of cardiovascular system. The control pathways that participate in feedback mechanisms (baroreceptors and cardiopulmonary receptors) are described to explain the interaction between hemodynamics and autonomic nerve control in the circulation. Based on a set-point model, the computational aspects of reflex control are explained. In final chapter we present the present research trend in this field and discuss the future studies of cardiovascular system modeling.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.318-318
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• 2003

The current study was performed to observe the effects of Panax ginseng (PG) and P. quinquefolium (PQ) on hemodynamics such as blood flow rate (BF), blood flow velocity (BV), heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) and body temperature (BT) in healthy young men. This is a randomized, single-blind study observed during 6 hrs after orally single administration of PG and PQ groups. (omitted)

• Journal of Chest Surgery
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• v.10 no.1
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• pp.28-37
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• 1977

Authors had performed experimental study for ventilatory functions & pulmonary hemodynamics following reimplantation of lung. Preoperative & postoperative hemodynamic studies were obtained. A significant reduction in arterial $PO_2$ and $PCO_2$ was observed with the first few days. But these changes returned to near control levels from 1 week after operation in long-term survivors. Also abnormal pulmonary hemodynamic values returned toward control levels within 1 to 3 weeks, with the exception of a residual increase in pulmonary vascular resistance. Microscopically minimal focal pulmonary edema and limited alveolar infiltration developed in the reimplanted lung. But these changes never increased after the their postoperative day and were completely resolved by 1 to 3 weeks after autotransplantation.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.186-189
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• 2005

In a clinical setting, developing a reliable method for the automated drug infusion system would improve a drug therapy under the unexpected and acute changes of hemodynamics. The conventional proportional-integral-derivative (PID) controller might not be able to achieve maximum performance because of the unexpected change of the intra- and inter-patient variability. The fuzzy PID control and the conventional PID control were tested under the unexpected response of mean arterial blood pressure (MAP) to a vasopressor agent during acute hypotension. Compared with the conventional PID control, the fuzzy PID control performed the robust MAP regulation regardless of the unexpected MAP response (average absolute value of the error between target value and actual MAP: 0.98 vs. 2.93 mmHg in twice response of the expected MAP and 2.59 vs. 9.75 mmHg in three-times response of the expected MAP). The result was due to the adaptive change of the proportional gain in PID parameters.

• Journal of Acupuncture Research
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• v.21 no.5
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• pp.241-248
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• 2004

Objectives : The purpose of this study is to examine the hemodynamic characteristics of pulse point. Methods : The computational analysis algorithms of arterial tree system was derived. In order to investigate the effect of internal organ on the pulse point, the diameter of celiac artery was reduced by half. Results : The sensitivity of flow change at the Inyoung(Renying) is better than that of the Chongu(Cunkou). but the Inyoung was worse than the Chongu in the point of the left and right symmetry. The pressure changes at the Inyoung and the Chongu were in the similar range. Conclusions : It was found from the result that the Chongu shows the more symmetrical hemodynamic characteristics than the Inyoung.

• 한국전산유체공학회:학술대회논문집
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• 1999.11a
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• pp.152-157
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• 1999

For the simulation of the blood flow in coronary artery, the system modeling of coronary hemodynamics is combined with CFD technique. The blood flow in coronary artery interacts with the global coronary circulation. Especially in case of the coronary artery with stenosis, the interaction plays an important role in the hemodynamics of the circulation. In this study we present a combined numerical approach using both the CFD technique for flow simulation and the global system model of coronary circulation. We use a lumped parameter model for the global simulation of coronary circulation whereas the finite element method is employed to compute the viscous flow field in stenosed coronary artery, The time variation of the pressure drop due to stenosis is obtained from the proposed numerical method. Numerical results shows that the flow resistance and pressure drop due to stenosis has a relatively large value in systole.