• Journal of computational fluids engineering
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• v.20 no.3
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• pp.79-86
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• 2015

A blood pump is an important part of a cardiac assist device. Since the shear rate in blood is known to be a primary factor on hemolysis generation, it has been very important to evaluate hemolysis inside blood pumps for understanding performance and reliability of cardiac assist devices. In this study, hemolysis generation inside blood pumps is analyzed using CFD with power-law based models for the blood damage index(BDI), in order to overcome difficulties in measuring hemolysis by experiment. The BDI values in blood pumps can be evaluated using Lagrangian or Eulerian approaches. In this study, several Lagrangian and Eulerian approaches are compared to estimate the efficiency of the numerical methods in a practice sense. It is found that the Eulerian approaches are advantageous in terms of the efficiency and robustness. Two different Eulerian approaches are used to evaluate the BDI values of a few commercial blood pumps. For the conditions of extracorporeal membrane oxygenator(ECMO) and ventricular assist device(VAD), local generation of hemolysis is analyzed using divided regions of blood pumps, in order to investigate the effects of the pump geometry.

• Journal of Chest Surgery
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• v.24 no.11
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• pp.1045-1057
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• 1991

Over the past four decades after World War II a great deal of data and clinical experiences have been accumulated relating to the diagnosis and surgical treatment of cardiovascular diseases in Korea. Clinical data after the first open heart surgery by Professor Yung Kyoon Lee on August 7, 1959 up to 1984 revealed the total number of cardiovascular surgery in Korea as 13,100 cases performed in 22 institutes with overall hospital mortality of 7.7%[Cardiovascular Surgery in Korea 1985], Publishing committee of the Korean Thoracic and Cardiovascular Surgical Society collected the data of cardiovascular surgical cases in Korea again in between 1985 and 1990 from 38 institutes out of total 42 institutes of open heart centers in Korea. The results are: 1. The survey reply ratio was 90.5%[38 out of 42 institutes]. 2. Of the total 30,061 cases of cardiovascular surgery reported from 38 institutes 1,402 cases were failed as hospital mortality of 4.7%[4.5% of the 21,761 operations for congenital, and 5.2% of the 8,300 operations for acquired heart diseases]. Out of the total congenital cases, 17,303 cases were acyanotic group with a operative mortality as 2.0%, and 4,458 cases were cyanotic group with a hospital mortality as 14.le The incidence of corrective operations for complex congenital cardiac anomalies were increasing recently with decreasing age group. 3. During the year in 1990, 38 institutes performed 5,427 cardiovascular surgery with a hospital mortality of 3.4%. 4. Of the total cumulative 6,458 cases for cardiac valve surgery more than 90% cases were put to prosthetic valve replacement with hospital mortality as 4.8%. And the incidence of re-Do valve surgery was increasing recently as 13.1% in 1990. 5. Coronary artery bypass graft was increasing recently with 7.9% of hospital mortality in total 440 cases. Intracardiac operation for intractable arrhythmia was started since 1987 as 49 cases in total. Experiences on VAD and ECMO were also reported sporadically in recent year. 6. Home made oxygenator[OXYREX] is now in clinical use, and under animal experiment for clinical trial in near future.

• Journal of Chest Surgery
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• v.51 no.1
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• pp.22-28
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• 2018

Background: Lung transplantation is a life-saving procedure in patients with end-stage lung disease, and is increasingly performed in Korea. Methods: We retrospectively evaluated the outcomes of patients who received a lung transplant at Asan Medical Center between January 2008 and December 2016. Thirteen of 54 patients experienced multiorgan transplantation; the remaining 41 who received only lung grafts were included. Results: The mean age of the lung transplant recipients was 44.6 years; 27 were men and 14 were women. The most frequent reasons were idiopathic interstitial pneumonia (21 of 41 patients, 51.2%), interstitial lung disease (9 of 41, 22.0%), and bronchiolitis obliterans after bone marrow transplantation (7 of 41, 17.1%). The median waiting time was 47 days, and many patients received preoperative intensive care (27 of 41, 65.9%), ventilator support (26 of 41, 63.4%), or extracorporeal life support (19 of 41, 46.3%). All 41 patients received bilateral lung grafts. Ten deaths occurred (24.3%), including 5 cases of early mortality (12.2%) and 5 cases of late mortality (12.2%). The 1-, 3-, and 5-year survival rates were 78.9%, 74.2%, and 69.3%, respectively. Conclusion: Despite a high percentage of patients who required preoperative intensive care, the transplantation outcomes were acceptable.

• Journal of Chest Surgery
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• v.15 no.4
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• pp.432-439
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• 1982

Congenital posterolateral diaphragmatic hernia [Bochdalek hernia] is the result of a congenital diaphragmatic defect in the posterior costal part of the diaphragm in the region of the tenth and eleventh ribs. There is usually free communication between the thoracic and abdominal cavities. The defect is most commonly found on the left [90%], but may occurs on the right, where the liver often prevents detection. The male to female ratio is 2:1. Owing to the negative intrathoracic pressure, herniation of abdominal contents through the defects occurs, with resultant collapse of the lung. Shifting of mediastinum to the opposite side and compression of the opposite lung occurs. Most often these hernias are manifestated by acute respiratory distress in the newborn. A second, but less well recognized, group of patient with Bochdalek hernia survive beyond the neonatal period, usually present at a later time with "failure of thrive, intermittent vomiting, or progressive respiratory difficulty. " The diagnosis can often be made on clinical ground from the presence of respiratory distress, absence of breath sounds on the chest presence of bowel sounds over the chest . Roentgenogram of the chest confirm the diagnosis. Obstruction and strangulation have been reported but are rare. Treatment consists of early reliable identification of these congenital diaphragmatic hernia with high risk and surgical repairment. and postoperative pharmacological management with extracorporeal membranous oxygenation [=ECMO] support in the period of intensive care. On the surgical approach, for defects on left side, an abdominal incision is preferred, because of the high incidence of malrotation and obstructing duodenal bands. In the neonate, the operative mortality may be appreciable, but, later repair almost always is successful. During the period from 1972 to 1982, 4 cases of congenital Bochdalek hernia were experienced at the Kyung-Hee University Hospital.

• Journal of Chest Surgery
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• v.34 no.4
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• pp.356-360
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• 2001

일시적 혹은 단기간의 심폐보조는 여러 형태의 심부전에서 널리 이용되어 왔다. 이 중 체외막산소화장치는 고식적 치료에 반응없는 환자에서 주로 사용되는데, 소아에서는 자주 이용되어 왔으나 성인에서는 그 적응증이 명확하지 않았으며 결과도 만족스럽지 못했다. 환자는 승모판 협착증을 가진 32세의 여자로 제왕절개술후 발생한 폐부종으로 내원하였다. 내원시 환자는 쇽상태로 강심제, 폐혈관확장제, 이뇨제등에 반응이 없었다. 우측 대퇴정-동맥캐뉼라를 통하여 14시간동안 체외막산소화장치를 이용하였으며, 환자상태는 가동 즉시 호전을 보였다. 이후 양측판막치환술을 시행하였고 수술 후에도 체외막산호화장치를 지속하였다. 체외막산호화장치는 수술시간을 포함하여 모두 62시간동안 가동하였으며, 이탈(weaning)은 안정된 혈류역학, 호전된 폐부종, 기저질환의 교정등을 통하여 성공적으로 이루어졌다. 환자는 판막수술 후 30일째 특별한 합병증없이 퇴원하였다.

• Journal of Chest Surgery
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• v.44 no.5
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• pp.343-347
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• 2011

Background: Acute pulmonary thromboembolism is fatal because of abruptly occurring hypoxemia and right ventricular failure. There are several treatment modalities, including anticoagulation, thrombolytics, ECMO (extracorporeal membrane oxygenator), and thromboembolectomy, for managing acute pulmonary thromboembolism. Materials and Methods: Medical records from January 1999 to December 2004 at our institution were retrospectively reviewed for pulmonary thromboembolectomy. There were 7 patients (4 men and 3 women), who underwent a total of 8 operations because one patient had post-operative recurrent emboli and underwent reoperation. Surgery was indicated for mild hypoxemia and performed with CPB (cardiopulmonary bypass) in a beating heart state. Results: The patients had several symptoms, such as dyspnea, chest discomfort, and palpitation. Four patients had deep vein thromboembolisms and 3 had psychotic problems, specifically schizophrenia. Post-operative complications included hemothorax, pleural effusion, and pericardial effusion. There were two hospital deaths, one each by brain death and right heart failure. Conclusion: Emergency operation should be performed when medical treatments are no longer effective.

• Korean Chemical Engineering Research
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• v.49 no.2
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• pp.238-243
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• 2011

In this study, we attempted a structural analysis in order to design a balloon type extracorporeal membrane oxygenator that can induce blood flow without using blood pumps for the purpose of complementing the weakness in the existing extracorporeal membrane oxygenator. To analyze the flow characteristic of the blood flow within the virtual model of extracorporeal membrane oxygenator, computational fluid dynamics(CFD) modeling method was used. The operating principle of this system is to make the surface of the extracorporeal membrane oxygenator keep contracting and dilating regularly by applying pressure load using a balloon, and the 'ime Function Value'that changes according to the time was applied by calculating a half cycle of sine waveform and a cycle of sine.waveform Under the assumption that the uni-directional blood flow could be induced if the balloon type extracorporeal membrane oxygenator was designed as per the method described above, we conducted a structural analysis accordingly. We measured and analyzed the velocity and pressure of blood flow at both inlet and outlet of the extracorporeal membrane oxygenator through CFD simulation. As a result of the modeling, it was confirmed that there was a flow in accord with the direction of the blood by the contraction/dilation. With CFD simulation, the characteristics of blood flow can be predicted in advance, so it is judged that this will be able to provide the most optimized design in producing an extracorporeal membrane oxygenator.

• Korean Journal of Clinical Laboratory Science
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• v.54 no.4
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• pp.293-297
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• 2022

In 2022, Korea reported a total of 224 perfusionists, employing nurses or clinical laboratory technologists (also known as medical technologists) to provide hospital self-education or reliable education. In 2021, the total number of perfusionists in Japan was 2,100, mainly supported by clinical engineering technologists. During the same period, the number of perfusionists reported in the United States was 4,212, who had received training in the master's program, post-bachelor certificate program, and bachelor's program. Most personnel in the USA were graduates of healthcare sciences or life sciences. Perfusionists must be knowledgeable in heart anatomy, physiology, pharmacology, pathology, hemodynamics, laboratory analysis, and quality assurance, as well as techniques to operate the cardiopulmonary bypass machine (heart-lung bypass machine). These are jobs similarly handled by clinical laboratory technologists. The importance of perfusionists became more prominent during two major crises: the MERS-CoV and COVID-19 pandemic. Currently, perfusionists play a significant role in the rapidly expanding field of extracorporeal membrane oxygenation (ECMO) and extracorporeal circulation during cardiac surgery. Results of the current study indicate that hospitals offering cardiac surgery and infectious disease hospitalization need to be institutionalized to secure a certain number of qualified perfusionists. In the future, we look forward to establishing a perfusion technology association under the Korean Society for Clinical Laboratory Physiology to provide academic exchanges.

• Journal of Chest Surgery
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• v.42 no.4
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• pp.464-472
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• 2009

Background: We analyzed the clinical results and the factors for survival of patients who underwent extracorporeal life support system after adult cardiovascular surgery. Material and Method: We retrospectively reviewed the medical record of 44 patients (1.6% of the total adult cardiovascular surgical cases) who underwent the use of a ventricular assisted device or extracorporeal membrane oxygenation from January 2002 to August 2008. There were 32 (72.7%) males and their mean age was 61.7$\pm$14.9(range: 20$\sim$73) years old. The mean duration of extracorporeal life support system was 5.3$\pm$3.0 (range: 1$\sim$12) days. Result: Of these 44 patients, 24 (54.5%) patients were successfully weaned from the extracorporeal device. Eighteen (40.9%) survivors were able to be discharged from the hospital. Complications were noted in 38 patients (86.4%). An emergency operation, no usage of a concomitant intraaortic balloon pump and major complications during use of the extra corporeal life support system such as bleeding, flow instability and renal failure were identified as significant risk factors for poor survival on univariated analysis. Owing to educational support and a continuous renal replacement therapy system, the clinical outcomes of these patients have improved since 2006. On multivariated analysis, renal failure and bleeding during extracorporeal life support were significant risk factors for poor survival. Conclusion: Although using. extracorporeal life support systems after adult cardiovascular surgery revealed acceptable clinical results, determining the optimal treatment strategy and further well designed larger studies are needed to improve the survival rate of patients who undergo extracorporeal life support after adult cardiovascular surgery.