• 대한한방내과학회지
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• 제25권3호
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• pp.440-450
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• 2004

Objectives: Uwhangchungsim-won(UC) has been used in the treatment of a wide variety of conditions including stroke, hypertension, arterosclerosis, autonomic imbalance, and mental instability, in Korean traditional hospitals. The aim of this study was to evaluate the effect of DC on cerebral hemodynamics and to determine the appropriate dosage. Methods: We studied changes in hyperventilation-induced cerebrovascular reactivity and mean blood flow velocity of the middle cerebral arteries(MCAs) were studied by means of transcranial Doppler ultrasound. Changes in mean blood pressure, pulse rate and expiratory CO2(PECO2) were observed using Cardiocap TM/5. Six healthy young volunteers who were administrated with full doses of DC for group A, and half doses for group B. Six other healthy subjects comprised the control group. The evaluation was performed during basal condition, and repeated at 20, 40, 60, 120, and 180 minutes after administration. Results: Increases of cerebrovascular reactivity and mean blood flow velocity in the middle cerebral artery in group A were significantly different compared with group B and the control group (p<0.1). Mean blood pressure, pulse rate and expiratory CO2 did not change during the observation and were not different among these three groups. We observed that in cerebrovascular reactivity induced hyperventilation, group A was most effective at 40 minutes after administration, and its effectiveness lasted for 120 minutes. Conclusions: This study provides evidence for UC, in full doses, as an agent for dilation of the cerebral arteriols to increase hyperventilation-induced cerebrovascular reactivity as a consequence of faster recovery of blood flow velocity.

• 대한방사선기술학회지:방사선기술과학
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• 제31권3호
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• pp.267-276
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• 2008

본 연구는 20세에서 50세까지 건강한 남성 지원자를 대상으로 내경동맥과 내경정맥의 혈류속도를 측정하기 위하여 2D-PC MRA를 촬영했다. 2D-PC MRA는 제4-5경추디스크를 지나는 FOV 24cm 넓이로 횡단 촬영하여 내경동맥과 내경정맥의 혈류속도를 넥타이를 매지 않은 상태와 세게 맨 상태에서 각각 측정하였다. 넥타이를 매지 않았을 때 내경동맥의 평균 혈류속도 최고치는 우측 72.13cm/sec, 좌측 74.96cm/sec (양측 평균 73.54cm/sec)이였고 내경정맥의 평균 혈류속도 최고치는 우측 -34.45cm/sec, 좌측 -24.99cm/sec(양측평균 -29.72cm/sec)였다. 그러나 넥타이를 세게 매었을 때 내경동맥의 평균 혈류속도 최고치는 우측 61.35cm/sec, 좌측 65.19cm/sec(양측 평균 63.27cm/sec)이며 내경정맥의 혈류속도 최고치는 우측 -22.14cm/sec, 좌측 -17.93cm/sec (양측 평균 20.03cm/sec)였다. 목에 세게 넥타이를 맨 경우가 넥타이를 매지 않은 상태 보다 양쪽 내경동맥의 평균 혈류속도가 86% (63.27/73.54cm/sec)로 약간 감소하는 반면 양쪽 내경정맥의 평균 혈류속도는 67%(-20.03/-29.72cm/sec)로 유의성 있게 감소하였다(P<0.05). 따라서 넥타이를 세게 매었을 때 내경정맥의 순환에 미치는 영향(33%의 혈류속도감소)이 내경동맥(14%의 혈류속도감소) 보다 유의성 있게 큰 것을 알 수 있었다(P<0.05). 결론적으로 본 연구결과는 2D-PC MRA를 이용하여 넥타이를 목에 세게 매었을 때 순간적으로 양쪽 내경정맥이 내경동맥보다 상대적으로 압박되어 혈류속도가 의미 있게 감소되며 일시적 폐쇄가 되는 소견을 보였다. 이 경우 넥타이를 목에 세게 매고 생활을 하는 경우에 대변을 보거나 또는 세면을 하는 등 일상적인 생활에서도 예기치 않게 일시적으로 내경정맥혈관이 압박되어 폐쇄되며 이차적으로 두개강 내의 정맥성고혈압을 일으켜 뇌졸중의 요인이 될 수 있는 것으로 유추된다.

• 대한한방내과학회지
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• 제35권1호
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• pp.24-36
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• 2014

Objectives : This study was performed to evaluate the effects of moxibustion on cerebral blood flow, peripheral blood flow and blood pressure. Methods : We designed a randomized, cross-over study that included 20 healthy, male volunteers who were randomly assigned to one of two groups (the moxibustion group or the control group). The initial trial was followed by a washout period of one week before the groups were switched and the trial repeated. The cerebral blood flow and peripheral blood flow of the volunteers in both groups were measured by mean velocity (Vm), peak systolic velocity (Vs), pulsatility index (PI), perfusion units (PU) and mean blood pressure (BP) before the intervention (baseline), 30 minutes after the intervention, and again 60 minutes after the intervention. Results : 1. The Vm increased significantly in the moxibustion group. The Vs also constantly increased in moxibustion group, but there was no significant difference. 2. The PI decreased significantly in the control group at 0-30 minutes and in the moxibustion group at 30-60 minutes. 3. The PU constantly decreased in moxibustion group. In control group, the PU decreased at 30 minutes and increased slightly at 60 minutes. 4. The mean blood pressure did not show any significant difference between the two groups. Conclusions : This study shows that moxibustion at CV12 increased the cerebral blood flow. Based on this result, we can suggest that moxibustion at CV12 might be helpful in improving the functional recovery of stroke patients. However, further research needs to be conducted on a larger numbers of subjects in order to confirm these effects.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.705-706
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• 2002

Hemodynamics of the TPLS(Twin Pulse Life Support System) is numerically investigated to delineate the possibility of hemolysis in blood. Computational method employing finite element algorithm is utilized to solve the blood flow of the sac squeezed by moving actuator. We assume that the blood flow interacts with the sac material which is activated by the rigid body motion of the actuator. Valve dynamics at the ends of the sac is simplified as on/off type motion. We compute the transient viscous flow in the two-dimensional geometry of the blood sac. Incompressible laminar flow is simulated on the assumption of Newtonian fluid. Blood velocity has a step gradient near the throat of the sac formed by the moving actuator. According to the decrease of the gap size of blood passage, the magnitude of shear stress in the blood is dramatically increased. Numerical solutions show that the maximum value of shear stress in the blood flow in TPLS is relatively smaller than that of the roller type ECLS.

• 대한기계학회논문집A
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• 제32권5호
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• pp.444-450
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• 2008

The conventional studies of the aging effect on cardio-vascular system are mostly obtained from human experiences and can only provide local information. In this study, the effect of fatigue fracture of arterial wall on the blood pressure was investigated by hemodynamic analysis. The aging process was simulated with three stages. The pulse wave velocity increased with age. The systolic blood pressure increases consistently but diastolic blood pressure decreases with age. The simulated results show in good accordance with the clinical ones.

• Korea-Australia Rheology Journal
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• 제20권4호
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• pp.189-196
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• 2008

The pulsatile flow of blood through a stenosed artery under the influence of external periodic body acceleration is studied. The effect of non-Newtonian nature of blood in small blood vessels has been taken into account by modeling blood as a Casson fluid. The non-linear coupled equations governing the flow are solved using perturbation analysis assuming that the Womersley frequency parameter is small which is valid for physiological situations in small blood vessels. The effect of pulsatility, stenosis, body acceleration, yield stress of the fluid and pressure gradient on the yield plane locations, velocity distribution, flow rate, shear stress and frictional resistance are investigated. It is noticed that the effect of yield stress and stenosis is to reduce flow rate and increase flow resistance. The impact of body acceleration is to enhance the flow rate and reduces resistance to flow.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.959-963
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• 2006

A three-dimensional elastic blood vessel model with internal diameter variation is considered to investigate internal flow characteristics and effects of structural deformation. Also, computational analyses for both the rigid model and the fully-coupled FSI model have been conducted in order to compare the shear stress, pressure distribution, and flow velocity in detail. A 70% narrowing area of asymmetric blood vessel model was especially investigated to show the versatility of fluid-structure interaction phenomenon. The results reveal that effect of fluid-structure interaction is very important to accurately investigate the flow characteristics of the blood vessel.

• Annals of Clinical Neurophysiology
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• 제1권1호
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• pp.70-75
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• 1999

Trancranial Doppler(TCD) monitoring is a new application of ultrasonography which allows the nonivasive detection of blood flow velocity in the horizontal (M1) segment of the middle cerebral artery (MCA) and detects microembolic phenomena in the cerebral circulation. Recent studies emphasized the potential of using this technique in vascular surgery (carotid endarterectomy, cardiopulmonary bypass), interventional and intensive care setting. Although the disparity between CBF and blood flow velocity and number of microemboli could be used to prevent cerebral ischemic and embolism based on clinical studies. A reduction of more than 60% of MCA can reflex hemodynamic ischemic state and acoustic feedback of high intensity transient signals(HITS) from the TCD monitoring unit has a direct influence on surgical technique. TCD monitoring can immediately provide information about thromboembolism and hemodynamic changes, which may be a useful tool in the study and prevention of stroke.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.213-214
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• 1998

The important role of the ultrasonic Doppler system in the modem clinical medicine is to provide the clinical information of the vascular system. The ultrasonic pulsed wave(PW) Doppler system, a kind of the ultrasound Doppler system, is more available than the ultrasonic continuous wave(CW) Doppler system because it can evaluate the velocity and the direction of blood flow as well as the depth of vessel. However, the ultrasonic PW Doppler system has the disadvantage that the range of evaluating velocity of blood flow is limited(Nyquist limit). In order to solve this limit, we propose the algorithm for eliminating this aliasing in this paper. In addition, we propose the efficient signal processing algorithm.

• 대한의용생체공학회:의공학회지
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• 제7권2호
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• pp.139-146
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• 1986

본 논문은 tms 32010이라는 디지탈 신호 처리용소자를 사용하여 초음하 펄스 도플러 장치를 구현한 것이다. 도플러 장피란 초음파 신호의 송수신 과정에서 발생하는 도플러 효과를 이용하여 혈류의 속도를 측정하는 장치이다. 한 점에서의 속도를 측정하는 단일채널 도플러 장치에서는 실시간 고속 푸리에 변환기를 구현하여 도플러 주하수의 스펙트럼을 측정함으로서 혈류속도를 측정하며 초음파 빔의 일직선상에서의 여러점을 동시에 측정하는 다중채널 도플러 장치에서는 영점교차검출기를 구현하여 평균주파수를 측정하였다. 자중채널 장치는 직렬처리법을 사용하여 하드웨어를 간단히 하였으며 8점에서의 속도를 측정할 수 있도록 하였다.