• 동력기계공학회지
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• 제11권2호
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• pp.38-43
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• 2007

전자기적으로 지지되는 임펠러를 가진 원심 혈액 펌프는 기존의 심장 펌프에 비해 많은 장점을 가지고 있지만, BVAD의 틈새에서 발생하는 유체 동역학적인 문제는 여전히 규명이 되지 않은 상태이다. 본 연구에서는 BVAD의 틈새에서 발생하는 혈액외상(blood trauma)의 예측에 대한 연구에 중점을 두고 있다. 일반적으로 원심 혈액 펌프의 설계를 위해 전자기적으로 지지되는 원심 혈액 펌프의 디스크 틈새에서 발생하는 혈액의 손상을 평가하는 방법으로 CFD를 이용한 방법이 널리 이용되고 있다. 따라서, 본 연구에서는 초기 원심 혈액 펌프의 설계 단계에서 펌프의 특성을 평가하기 위하여, 축 방향 틈새의 영향과 회전수 변화에 따른 누수경로의 전단 응력의 크기 평가를 CFD를 사용하여 해석하여 보았다.

• 대한의용생체공학회:의공학회지
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• 제12권1호
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• pp.29-34
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• 1991

Ventricular assist device(VAD) has been clinically applied as a temporary circulatory sup- porting system in the patients with severe heart failure, but small sized VAD for infant is not available. The purpose of tilis paper is to introdIAce small sized VAD and presents the result of in vitro test. Sejong VAD is diaphragmatic type of pneumatic pump and stroke volume is 11cc. Cardiac outputs of the Sejong VAD were measured by overflow tank under variable conditions of driving parameters. The cardiac output was 1.3 1/min at the heart rate of 120 per minute, left atrial pressure of $15cmH_2O$, percent systole of 43%, driving pressure of 240 mmHg, vacuum pressure of -40 mmHg, and mean aortic pressure of 70 mmHg. No mechanical problem was developed during the continuous in vitro test for 3 months.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.514-517
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• 1995

A new stroke output control algorithm with a fuzzy logic for an electrohydraulic left ventricular assist device(EH-LVAD) was developed. The EH-LVAD pumps out blood from left atrium actively. Excessive suction of blood may cause fatal damage in left atrium. The LVAD has to provide a maximal stroke output without collapse of left atrium. In this study a new fuzzy algorithm for predicting and detecting suction and doing proper action on LVAD without using an extra pressure sensor but with bellows pressure signal and motor current signal is developed. The performance of the fuzzy control algorithm is demonstrated by the results from mock circulatory experiments.

• Journal of Chest Surgery
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• 제56권2호
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• pp.147-150
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• 2023

A child being supported with an extracorporeal ventricular assist device, such as the Berlin Heart EXCOR (Berlin Heart GmbH, Berlin, Germany), must have at least 2 large cannulae for a long period. Management of cannula wounds is crucial since a cannula forms a track of prosthetic material passing the mediastinum to the heart. Deep wound complications, if they occur, can be troublesome and difficult to control with conventional methods. We applied vacuum-assisted closure to a patient who had Berlin-Heart EXCOR and a gap at the cannulation site. Herein, we describe the technical aspects of management in detail.

• 대한의용생체공학회:의공학회지
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• 제14권2호
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• pp.163-167
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• 1993

We developed a ventricular assist device(VAD) to be used as a bridge to heart transplantation or a circulatory assist device for patients with end-stage heart disease or poor myocardial function after cardiac surgery. It is a pneumatic and diaphragm-type VAD and its stroke volume is 90 cc. The upper housing and diaphragm is made of a segmented polyurethane and the lower back plate is made of a polycarbonate. Two Carbomedics$^R$ mechanical valves are used as inlet and outlet valves. It was tested in vitro and the cardiac output of the VAD was 7 L/min at a heart rate of 70 bpm. The line pressure from a pressure transducer inserted in the pneumatic line was recorded and compared with the ideal pressure tracing.

• 대한흉부심장혈관외과학회:학술대회논문집
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• 대한흉부외과학회 1993년도 제25차년차학술대회 및 총회
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• pp.70-70
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• 1993

• Journal of Chest Surgery
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• 제30권5호
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• pp.528-532
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• 1997

심근경색증의 합병증으로 발생한 심실중격 파열의 조기 수술 교정 후 2례에서 술후 7일 및 40일 째 다시 심실중격 결손이 발견되어, 진단 후 77일 및 10일에 각각 재수술을 시행, 먼저 봉합 한 부위와는 다른 부위 에 심실중격 결손이 다시 발생하여 있는 것을 관찰, 이를 보철편을 이용 봉합하여 양호한 결과를 얻어 심실 중격의 파열에 대한 조기 수술법이 적절한 치료법임을 확인하고, 추후 재발생되는 심실중격의 파열 등에 대 해서도 적절한 심근 보호법 및 대동맥내 풍선 펌프 등 심근보조 장치를 적극적으로 이용함으로서 보다 안전 하게 수술 치료할 수 있을 것으로 생각된다.

• 대한의용생체공학회:의공학회지
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• 제27권2호
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• pp.78-82
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• 2006

The ventricular assist device(VAD) helps to reduce the overload against the patient's native heart(NH). The pulsatile VAD pumps out the ventricular blood to the aorta with pulsatile flow. If the VAD pulsates simultaneously with the NH, the ventricle of the NH could confronts abnormally elevated aortic pressure, and this could deteriorate the ventricle rather than assist to recover it. Thus counterpulsation algorithms to avoid copulsation have been adopted by many VADs, but these methods utilize electrocardiography or arterial pressure signals, which may have difficulties to acquire consistently for a long period. In this study, the copulsation estimation algorithm for the counterpulsation is developed using the VAD outlet pressure signal. The VAD outlet pressure signal is good to maintain for a long time and the sensor part could be integrated to the VAD as a built-in module. From the VAD outlet pressure signal and its pump rate information calculated with Fast Fourier Transform, pulse peaks by the VAD and the NH were extracted and the next copulsation time at which the VAD and the NH would pulsate simultaneously was estimated. This estimation algorithm was implemented by using PC MATLAB software and tested for various pump rate conditions with mock circulation system. For each condition, the copulsation time was estimated successfully. Consequently, the results showed the possibility to use the outlet cannula pressure signal in the copulsation estimation.

• Journal of Chest Surgery
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• 제53권6호
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• pp.368-374
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• 2020

Background: The extracorporeal ventricular assist device (e-VAD) system is designed for left ventricular support using a permanent life support console. This study aimed to determine the impact of temporary e-VAD implantation bridging on posttransplant outcomes. Methods: We reviewed the clinical records of 6 patients with the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profile 1, awaiting heart transplantation, who were provided with temporary e-VAD from 2018 to 2019. The circuit comprised a single centrifugal pump without an oxygenator. The e-VAD inflow cannula was inserted into the apex of the left ventricle, and the outflow cannula was positioned in the ascending aorta. The median follow-up duration was 8.4±6.9 months. Results: After e-VAD implantation, lactate dehydrogenase levels significantly decreased, and Sequential Organ Failure Assessment scores significantly improved. Bedside rehabilitation was possible in 5 patients. After a mean e-VAD support duration of 14.5±17.3 days, all patients were successfully bridged to transplantation. After transplantation, 5 patients survived for at least 6 months. Conclusion: e-VAD may reverse end-organ dysfunction and improve outcomes in INTERMACS I heart transplant patients.

• Journal of Chest Surgery
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• 제30권4호
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• pp.357-362
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• 1997

심실보조장치 등의 단기간 사용을 위하고 경제적이고 항혈전성이 높은 판막을 개발하기 위해 고분자 판막을 연구 중인데 판막의 혈액적합성을 시험하기 위해 동물실험을 시행하였다. 고분자판막은 외경이 각각 22 mm, 18 mm, 16 mm인 단엽식 판막이다. 열림판과 프레 임 모두 재질을 폴리우레탄 계로 제작하 여 유연하고 완전한 접착이 되도록 하였다. 총 7 마리의 황견에 이식하였는데 이식 위치에 따라 3가지로 분류하였다. 첫 번째는 심실보조장치의 유입구에 삽입하였고,두 번째는 대동맥에,세 번째는우심실과 우심방사이에 인조혈관을 이용하여 이식하였다. 가장 긴 생존 기간은 20일 이었다. 판막의 항혈전성 및 용혈현상을 입증하기 위 해 헤모글로빈, 헤마토크리트, 적혈구수, 백혈구수, LDH, 혈색소 등을 검사하였 다. 본 연구는 좀 더 개선하면 고분자판막이 심실보조장치에 단기간 사용 가능한 판막이 될 수 있는 가능성을 보여주었다.