선인장 양심실 보조장치의 설계 및 임상적용을 위한 평가

민병구,박찬영,최재순,이혁수,황창모,김삼성,윤걸중,김종원,선경,이경갑,정종태,김원곤 제주대학교 인공심장이식연구소 2001 인공심장 연구 Vol.2 No.1

현재 개발되고 있는 맥동형 이식형 인공심장은 완전이식형 인공심장과 좌심실보조장치 뿐이다. 좌심실보조장치를 장착한 환자의 10~15%가 우심실의 보조를 필요로하고 완전이식형 인공심장의 장착을 위해서는 자연심장을 제거해야하는 상황에서 이식형 양심실보조장치에 대한 필요성이 대두되고 있다. 본 연구진은 완전이식형 인공심장으로 개발된 한국형 인공심장을 개선하여 양심 실 보조장치를 개발하였다. 양심실보조장치는 이동형 작동기식 미케니즘을 이용하고 있으며 에너지 변환장치와 감속기로 구성된 작동기와 혈액주머니, 그리고 내장형 제어기로 구성되어 있다. 선인장 펌프로 명명된 KAH350은 캐뉼라의 연결을 위한 커넥터를 포함하여 길이 177mm, 폭 164mm, 높이 67 이고 무게 780g이며 최대 심박출량은 5L/min 이다. 양심실보조장치로 개발된 선인장펌프는 좌심실보조장치로도 응용이 가능하다. 이식적합성과 생체적합성을 평가하기 위하여 좌심실보조장치로 5회, 양싱실보조장치로 6회의 동물실험을 수행하였다. 각각 최장 28일간 생존하였으며 11회의 동물실험중 장치의 결함에 의한 것이 3회 있었는데 이들은 모두 전자장치의 결함과 방수처리문제였다. 현재 이식적합성과 일박출량을 향상시킨 KAH400모델이 개발중이다. The types of pulsatile implantable artificial hearts that are on the way of development and have been developed are totally implantable artificial heart and implantable left ventricular assist device (LVAD). Approximately 10% to 15% of all patients Implanted with wearable VADs have required right heart support with another device. And it is reluctant to patient who should remove his or her own heart to be implanted with total artificial heart. These situations drive the development of implantable bi-ventricular assist device (BVAD). The Korean BVAD was develophed by modifying the moving actuator type Korean artificial heart. This electro-mechanical BVAD comprises actuator including energy converter and reduction gear train, blood sacs, and internal motor and energy controllers. The KAH350 which is named as 'Cactus Pump' is 177mm in length, 164mm in width, and 67mm in thickness including connectors and nuts. The weight and maximum cardiac output of Cactus Pump is 780g and 5L/min, respectively. The Cactus Pump that was developed as BVAD could be used as LVAD by attaching compliance caps on the 2 ports of one ventricle. The animal experiments were undergone 5 times for LVAD, and 6 times for BVAD. The best records were 28 days survival in both applications. There were 3 times of device failure and they were all associated with electrical connection and hermetic sealing. The KAH400 that has improved anatomical fitting characterisitcs and stroke volume is on development.

한국형 인공심장 내의 혈류에 대한 수치해석적 연구

심은보,박명수,여종영,고형종,박찬영,민병구 제주대학교 인공심장이식연구소 2001 인공심장 연구 Vol.2 No.1

한국형 인공심장 내의 혈액 유동을 유한요소 코드인 ADINA를 사용하여 수치적으로 조사하였다. 그 동안 많은 실험을 통해서 밝혀진 중요한 문제점들 중의 하나는 바로 혈전 생성이다. 이것은 혈액 주머니내의 작용하는 과도한 높은 전단응력 또는 정체 영역과 밀접한 관련이 있다. 한국형 인공심장 내의 혈류는 액추에이터와 혈액주머니, 그리고 혈액의 상호작용에 의하여 정의될 수 있다. 여기에서 혈액은 비압축성, 뉴우턴 유체로 가정하였으며, 혈액주머니는 등방성 선형 고체재질로 가정하였다. 2차원 모델은 액추에이터와 혈액 주머니 사이의 접측 문제 및 고체-유체 상호작용 문제를 전부 고려하였다. 3차원 모델에서는 액추에이터에 의한 변형을 접촉문제를 혈액주머니 외부에 작용하는 압력조건으로 단순화하였다. 2차원 모델 계산결과에 의하면, 입구 및 출구 부근, 그리고 모서리 부근에서 전단응력의 세기가 매우 크다는 것을 발견할 수 있었다. 또한 위쪽 돌출부에서 속도가 매우 느려지는 정체 영역이 형성되었으며, 이는 실험에서 관찰된 혈전 생성영역과 거의 일치한다. 3차원 계산의 경우에도 역시 입구와 출구 부분에서 재순환 영역이 발견되었으며, 수축시에는 입구의 아래쪽에서, 이완시에는 출구의 아래쪽에서 정체영역이 생성됨을 알 수 있었다. One of the crucial problems which make the artificial heart operate improperly is the thrombus formation. Many experimental results show the thrombus formation is strongly retated with a high shear stress and the stagnation in the blood flow. Therefore study on the blood flow in artificial hearts is very important in a practical point of view. This thesis deals with the two- and three-dimensional unsteady blood flows in the Korean total artificial hearts(KTAH). It is numerically investigated by using the commercial finite element code ADINA. The flow in the sac of artificial heart results from the mutual interaction of the acuator, sac, and blood. Blood is assumed as an incompressible viscous Newtonian fluid, while the sac is considered to be elastic and isotropic solid material. The contact problem between the actuator and sac is included in the two-dimensional modelling. Because of the tremendously calculation time, the action of the actuator is replaced by the imposition of the time-varying pressure on the outer surface of the sac. Numerical results show a high shear stress distribution near the inlet and outlet corners of the sac. From two-dimensional calculation flow stagnation is seen to be found in the upper convex part of the sac. By comparing the numerical results with the experimental ones we can conclude the thrombus is generated in regions where blood flow stagnates or is very slow.

심부전에서 장기간의 양심실보조장치 이식이 혈역학적 지표에 미치는 영향에 대한 시뮬레이션

오세일,손대원,오병희,민병구,선경 대한순환기학회 2001 Korean Circulation Journal Vol.31 No.7

Total implantable Artificial Heat : Biophysical Aspects.

Min, Byoung Goo 가톨릭 의과학연구원 1997 가톨릭 의과학연구원 국제학술대회 Vol.1 No.-

The extra-corporeal artificial hearts and assist devices are presently used as temporary bridge device before the heart transplantation. However, the world wide problem of the serious donors shortage and no altenative therapeutic heart. For this purpose, many research teams are working for developing total artificial geart(TAH) before the year oj 2002. For a long-term, implantable TAH as a medical device and normal life with TAH requires the following diverse research; (1) anti-thrombotic. and antiinfection biomaterials, (2) the normal fluid pattern inside TAH. (3) physiological control to adapt the metabolic levels. (4) durabillity of mechanical and electrical components and bio-polymers. (5) power efficient electrical and mechanical system. (6) small size of pump and electrical energy-communication-control systems for total implantable TAH in small chest size of patients. Our research team has been developing the Korean Model of TAH with the moving actuator mechanism. as compared with the all other group's fixed actuator system to decrease the pump size. Also, we developed a surface modification technique for anti-thrombotic and anti-infection of the polyurethane blood sacs. The physiolocical control system is based on the extimations of the left and right atrial pressures. and the aortic and pulmonary pressures. Then, the stroke volume and the heart rate can be adjuste based upon these non-invasive pressure estimation. Animal experiments were performed to evaluate the hemodynamic. biochemical. and medical problems the pump using the sheeps as adult model small chest size. The biophysical aspects of TAH research and its results will be presented in this presentation.

The Artificial Heart in Korea

Goo, Min Byoung Medical Publications Korea 1990 Medical Progress Vol.12 No.12

Image Restoration in Dual Energy Digital Radiography using Wiener Filtering Method

Min, Byoung-Goo,Park, Kwang-Suk The Korea Society of Medical and Biological Engine 1987 의공학회지 Vol.8 No.2

Wiener filtering method was applied to the dual energy imaging procedure in digital radiography(D.R.). A linear scanning photodiode arrays with 1024 elements(0.6mm H 1.3mm pixel size) were used to obtain chest images in 0.7 sec. For high energy image acquisition, X-ray tube was set at 140KVp, 100mA with a rare-earth phosphor screen. Low energy image was obtained with X-ray tube setting at 70KVp, 150mA. These measured dual energy images are represented in the vector matrix notation as a linear discrete model including the additive random noise. Then, the object images are restored in the minimum mean square error sense using Wiener filtering method in the transformed domain. These restored high and low energy images are used for computation of the basis image decomposition. Then the basis images are linearly combined to produce bone or tissue selective images. Using this process, we could improve the signal to noise ratio characteristics in the material selective images.

Quantitative Analysis of Pulsatile Flow Contribution to Ultrafiltration

Lim, Ki Moo,Park, Joong Yull,Lee, Jung Chan,Kim, Jeong Chul,Min, Byoung Goo,Kang, Eung Taeck,Shim, Eun Bo Blackwell Publishing Inc 2009 Artificial Organs Vol.33 No.1

<P>Abstract</P><P>We evaluated the quantitative contribution of pulsatile flow to ultrafiltration (UF) in terms of fluid power, membrane stretch, and reduction of membrane layering. An in vitro comparison of the UF rate using pulsatile and roller pumps was performed with distilled water and bovine whole blood. The mean transmembrane pressure (TMPm) and UF rate were higher with the pulsatile pump for the same mean flow rate: 6.6 mm Hg and 21.1 mL/min higher on average for distilled water and 34.2 mm Hg and 31.4 mL/min higher on average for blood. The average UF rate was 8.4 mL/min higher with the pulsatile pump for the same TMPm with bovine blood. However, the relationship between the UF rate and the TMPm was independent of the flow configuration for distilled water. We showed that the higher UF rate in the pulsatile pump is mainly due to greater fluid power and reduction of membrane layering, while the membrane stretch was not an important factor.</P>

한국형 인공심장에 대한 동물실험(AnyHeart™)

선경,손호성,이성호,신재승,이혜원,김승철,원용순,이경갑,정종태,김종원,노양래,이혁수,민병구 제주대학교 인공심장이식연구소 2001 인공심장 연구 Vol.2 No.2

말기심부전증의 새로운 치료대안으로 제시되는 한국형 인공심장(AnyHeartTM)의 효용성과 안정성을 평가하기 위하여 동물실험을 실시하였다. 지난 2년간 고려대학교 안암병원과 제주대학교 동물병원에서는 총 28마리(송아지 18, 면양 4, 실험견 3, 말 2, 산양 1마리)의 다양한 동물에서 한국형 인공심장 이식실험이 실시되었으며, 좌심보조장치로 적용한 1예와 체외휴대형으로 적용한 각 1예를 제외하고 모두 심장보존형 인공심장(이식형 양심보조장치)의 형태로 완전 이식하였다. 수술방법은 주로 우측개흉법을 (Korea University Technique)을 사용하였다. 펌프 박출량은 최대 6 L/min로 평균 3-3.5 L/min를 유지되었으며, Fitting test 4례와 초기 적응과정의 2마리를 제외하고 모두 수술에서 회복되었다. 최장 관찰기간은 37일로 합병증 없이 건강한 상태에서 기초자료 확보를 위해 관찰을 임의종료하였다. 모든 생존동물에서 기계장치와 관련된 부작용은 발견되지 않았고, 임상적으로 나타나는 혈전전색 소견이나 간기능, 신기능, plasma hemoglobin, fibrinogen 등에 이상은 없었다. 적절하게 조기부검이 이루어진 경우에는 인공심장 내부에 혈전이 발견되지 않았고, 간/콩팥/비장 등의 중요장기에 병리검사에서도 전색소견은 발견되지 않았다. 결론으로, 한국형 인공심장은 생체 내에 이식하였을 때 안정적이며 기능이 우수한 것을 알 수 있었다. 한국형 인공심장은 현 상태에서 임상에 적용할 수 있다고 판단되며, 가까운 시일 내에 인체 내 안정성와 유효성에 대한 평가가 가능할 것으로 기대한다. Korean artificial heart (AnyHeartTM) is a new vision in the management of end stage heart failure. We performed the animal experiments to evaluate the performance and safety of AnyHeart. For last 2 years, 28 various animals (cattle 18, sheep 4, canine 3, goat 1) underwent AnyHeart implantation at Korea University Medical Center and Cheju University Animal Hospital. AnyHeart was applied as an implantable BVAD except a case of implantable LVAD or wearable BVAD. A standard technique of implantation was a right thoracotomy approach (Korea University Technique). The pump output was 6 L/min in maximum and 3-3.5 L/min in average. Other than 4 cases of fitting tests and 2 in the early learning period, all animals were recovered from the operation. The longest observation was made until 37th postoperative day, and the observation was terminated to get a control data while the animal was healthy without complications. All survivors were free from device-related morbidity, and there were no evidence of clinically significant thromboembolic episode, liver functions, renla function, plasma hemoglobin, fibrinogen abnormalities. Appropriate autopsy did not show thrombus in the device or embolism in the organs. Conclusively, AnyHeart has been proved efficient and safe during in-vive implantation. The authors believe that AnyHeart can be applied to clinical situations at the moment and expect to perform a clinical trial to test safety and efficacy in the human body within near future.

Cerebellar Embolization in Patients with Heart Murmur

Min Goo Lee,박종춘,Byoung Hee Ahn,정명호 전남대학교 의과학연구소 2011 전남의대학술지 Vol.47 No.1

A 76-year-old female present to the emergency department with dysarthria, dizziness,dyspnea. The patient had hypertension and atrial fibrillation. Brain MRI revealed right cerebellar infarction. Transthoracic echocardiography showed a large round mass in the left atrium. Transesophageal echocardiography showed large complex echogenic round mass lesion attached on left atrial side of interatrial septum. Coronary angiogram revealed round movable mass lesion in left atrium with feeding arteries originated from right coronary artery. She underwent removal of mass and Maze operation,and pathologic finding was compatible with myxoma.

Success rate of Ingrowing nail treatment according to the severity and management

( Byoung Joon So ),( Min Gun Yoo ),( Hee Joo Kim ),( Kyung Goo Lee ),( Il Hwan Kim ) 대한피부과학회 2012 대한피부과학회 학술발표대회집 Vol.64 No.3