• Clinical and Experimental Pediatrics
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• 제53권6호
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• pp.680-687
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• 2010

Patients with congenital heart diseases (CHD) are confronted with early- and late-onset complications, such as conduction disorders, arrhythmias, myocardial dysfunction, altered coronary flow, and ischemia, throughout their lifetime despite successful hemodynamic and/or anatomical correction. Rhythm disturbance is a well-known and increasingly frequent cause of morbidity and mortality in patients with CHD. Predisposing factors to rhythm disturbances include underlying cardiac defects, hemodynamic changes as part of the natural history, surgical repair and related scarring, and residual hemodynamic abnormalities. Acquired factors such as aging, hypertension, diabetes, obesity, and others may also contribute to arrhythmogenesis in CHD. The first step in evaluating arrhythmias in CHD is to understand the complex anatomy and to find predisposing factors and hemodynamic abnormalities. A practical stepwise approach can lead to diagnosis and prompt appropriate interventions. Electrophysiological assessment and management should be done with integrated care of the underlying heart defects and hemodynamic abnormalities. Catheter ablation and arrhythmia surgery have been increasingly applied, showing increasing success rates with technological advancement despite complicated arrhythmia circuits in complex anatomy and the difficulty of access. Correction of residual hemodynamic abnormalities may be critical in the treatment of arrhythmia in patients with CHD.

• International Journal of Vascular Biomedical Engineering
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• 제1권1호
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• pp.32-40
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• 2003

Axillo-bifemoral (Ax-Fem) bypass are now well accepted for bilateral iliac artery occlusion as the second best option. This extra-anatomical (unnatural) bypasses, however, have various hemodynamic liabilities affecting the patency. Hemodynamic conditions of each different type of Ax-Fem bypass were assessed with computer simulation model to determine the hemodynamically more sound type. Simulation models of five different types of Ax-Fem bypass were constructed. Our investigation based on the computer simulation models have shown distinct differences between two most popular Lazy-S type and Inverted-C type on the distribution of flow volume, shear stress and recirculation zone, etc., though both types have shown similar clinical results. Lazy-S type has shown better hemodyanmic status than inverted-C type. The theoretical advantage of "Lazy-S" type has never been adequately proved for its superiority clinically over the inverted-C type. Inverted-C type is now in more favor with clinically better results in spite of many hemodynamic liabilities including retrograde flow to the branching graft. The improvement of over-all long-term patency rate of various extra-anatomical bypasses is still warranted through proper correction of the hemodynamic liability. Even though clinical outcome of the extra-anatomical bypass has been equal regardless of the type of crossover femoral graft configuration, there are distinct differences on the hemodynamic characteristics among various types of configuration. Further hemodynamic study in the pulsatile flow status is warranted to correct hemodynamic defects with proper modification of various hemodynamic factors of each model.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.9-10
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• 2002

Human circulatory system between heart and tissue is not directly connected in normal condition but mandatory to go through the capillary system in order to fulfill its physiologic aim to deliver oxygen and nutrients, etc. to the tissue and retrieve used blood together with waste products from the tissue properly. When abnormal connection between arterial and venous system (AV fistula), these two circulatory systems respond differently to the hemodynamic impact of this abnormal connection between high pressure (artery) and low pressure (vein) system. Depending upon the location and/or degree (e.g. size and flow) of fistulous condition, each circulatory system exerts different compensatory hemodynamic response to this newly developed abnormal inter-relationship between two systems in order to minimize its hemodynamic impact to own system of different hemodynamic characteristics. Pump action of the heart can assist the failing arterial system directly to maintain arterial circulation against newly established low peripheral resistance by the AV fistula during the compensation period, while it affects venous system in negative way with increased venous loading. However, the negative impact of increased heart action to the venous system is partly compensated by the lymphatic system which is the third circulatory system to assist venous system independently with different hemodynamics. The lymphatic system with own unique Iymphodynamics based on peristaltic circulation from low resistance to high resistance condition, also increases its circulation to assist the compensation of overloaded venous system. Once these compensation mechanisms should fail to fight to newly established hemodynamic condition due to this abnormal AV connection, each system start to show different physiologic ${\underline{de}compensation}$ including heart and lymphatic system. The vicious cycle of decompensation between arterial and vein, two circulatory system affecting each other by mutually negative way steadily progresses to show series of hemodynamic change throughout entire circulation system altogether including heart. Clinical outcome of AV fistula from the compensated status to decompensated status is closely affected by various biological and mechanical factors to make the hemodynmic status more complicated. Proper understanding of these crucial biomechanical factors iii particular on hemodyanmic point of view is mandatory for the advanced assessment of biomechanical impact of AV fistula, since this new advanced concept of AY fistula based on blomechanical information will be able to improve clinical control of the complicated AV fistula, either congenital or acquired.

• Clinical and Experimental Pediatrics
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• 제62권7호
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• pp.245-251
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• 2019

Hemodynamically significant preterm patent ductus arteriosus (PDA) affects mortality; comorbidities such as necrotizing enterocolitis, intraventricular hemorrhage, and bronchopulmonary dysplasia; and adverse long-term neurodevelopmental outcomes in preterm infants, particularly in very low birth weight infants. However, recent studies have indicated that there is no consensus on the causal relationship between PDA and neonatal outcomes, the benefit of PDA treatment, the factors guiding the need for treatment, and optimal treatment strategies. Such uncertainty has resulted in wide variations in practice for treating preterm PDA between units, regions, and nations. Nowadays, there has been a paradigm shift to more conservative treatment for preterm PDA, and suggestions regarding selective management of preterm PDA considering risk factors and hemodynamic significance are increasing. Neonatologist-performed echocardiography and advances in modalities to assess hemodynamic significance such as biologic markers and near-infrared spectroscopy also help improve the efficacy of selective treatment of preterm PDA.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.753-758
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• 2003

The purpose of the present study was to establish the mechanism of the generation of atherosclerosis by analyzing the hemodynamic variables in the coronary artery where atherosclerosis occurs frequently. From the previous results, the stenosis phenomena due to atherosclerosis were related to not only biochemical reaction between blood and blood vessel but also the hemodynamic factors like flow separation and oscillatory wall shear stress. The present study aimed to investigate the causes of the generation and progression of atherosclerosis in the coronary artery. This study also aimed to develop the softwares which generate automatically three dimensional vascular models obtained by the angiogram images and the computer vision techniques. In the present study, the flow patterns for full three-dimensional hemodynamic characteristics were analyzed. To understand the three-dimensional hemodynamic characteristics, the wall shear stress distributions and secondary flows were investigated quantitatively.

• Neonatal Medicine
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• 제17권2호
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• pp.201-206
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• 2010

목적: 최근 미숙아에서 동맥관 결찰 술 후 설명할 수 없는 혈역동학적 불안정성에 대한 보고가 되고 있어 극소저체중아에서 동맥관 결찰술 후 발생하는 혈역동학적 불안정성의 위험 요인 및 임상 양상에 대해 알아보고자 하였다. 방법: 2002년 1월부터 2008년 12월까지 고려대학교 의료원내 3개 병원의 신생아 중환자실에서 치료 받은 재태 32주 미만의 극소저체중출생아에서 동맥관 결찰술을 시행 받은 환아 18명을 대상으로 하여 의무기록을 후향적으로 조사, 분석하였다. 수술 중 또는 수술 후 문제로 인한 혈역동학적 불안정성 이외에 설명할 수 없는 심폐 기능의 저하로 인공 호흡기 의존도의 증가와 혈압의 하강 등이 관찰된 환자를 혈역동학적 불안정군(hemodynamic instability group, HI)으로 정의하였다. 결과: 연구에 참여한 18명의 환아들의 재태 주수는 $27^{+6}{\pm}1^{+6}$주, 평균 출생 체중은 951${\pm}$245 g이었다. HI군은 7명(7/18, 39%)이었으며 혈역동학적 안정군(hemodynamic stability group, HS)은 11명(11/18, 61%)이었다. HS군에 비해 HI군은 출생 체중(1,033${\pm}$285 g vs. 821${\pm}$126 g, P=0.048)과 수술 시 체중(1,195${\pm}$404 g vs. 893${\pm}$151 g, P=0.042)이 작았으며, 재원기간이 길었고 (105${\pm}$29 vs. 141${\pm}$39, P=0.038) 심한 기관지 폐 이형성증의 빈도가 높았고(no/mild/moderate/severe, 2/5/2/2 vs. 0/1/2/4, P=0.038) 수술 전 $FiO_2$의 농도가 높았다(0.29${\pm}$0.06 vs. 0.38${\pm}$ 0.09, P=0.02). 18명 중 HS군에서 1명의 환아가 동맥관 결찰술 후 94일 째 패혈증으로 사망하였다. 결론: 극소저체중아에서 동맥관 결찰술 후 혈역동학적 불안 정성이 발생한 경우는 약 39%였다. 작은 출생 체중과 수술 시 체중, 수술 전 높은 산소 분압의 산소 투여가 동맥관 결찰술 후 혈역동학적 불안정성 발생의 위험인자가 될 수 있으며 아울러 혈역동학적 불안정성은 기관지 폐 이형성증의 유병률 및 중증도와 재원기간을 증가시킬 수 있음을 확인하였다.

• Journal of Korean Neurosurgical Society
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• 제66권3호
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• pp.228-238
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• 2023

Intraventricular hemorrhage (IVH) is a serious concern for preterm infants and can predispose such infants to brain injury and poor neurodevelopmental outcomes. IVH is particularly common in preterm infants. Although advances in obstetric management and neonatal care have led to a lower mortality rate for preterm infants with IVH, the IVH-related morbidity rate in this population remains high. Therefore, the present review investigated the pathophysiology of IVH and the evidence related to interventions for prevention. The analysis of the pathophysiology of IVH was conducted with a focus on the factors associated with cerebral hemodynamics, vulnerabilities in the structure of cerebral vessels, and host or genetic predisposing factors. The findings presented in the literature indicate that fluctuations in cerebral blood flow, the presence of hemodynamic significant patent ductus arteriosus, arterial carbon dioxide tension, and impaired cerebral venous drainage; a vulnerable or fragile capillary network; and a genetic variant associated with a mechanism underlying IVH development may lead to preterm infants developing IVH. Therefore, strategies focused on antenatal management, such as routine corticosteroid administration and magnesium sulfate use; perinatal management, such as maternal transfer to a specialized center; and postnatal management, including pharmacological agent administration and circulatory management involving prevention of extreme blood pressure, hemodynamic significant patent ductus arteriosus management, and optimization of cardiac function, can lower the likelihood of IVH development in preterm infants. Incorporating neuroprotective care bundles into routine care for such infants may also reduce the likelihood of IVH development. The findings regarding the pathogenesis of IVH further indicate that cerebrovascular status and systemic hemodynamic changes must be analyzed and monitored in preterm infants and that individualized management strategies must be developed with consideration of the risk factors for and physiological status of each preterm infant.

• Journal of Trauma and Injury
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• 제21권1호
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• pp.22-27
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• 2008

Purpose: Treatment and prognosis in patients with pelvic bone fracture depend on the characteristics of the fracture and the stability of the pelvic ring. The purpose of this study is to analyze the characteristics of and the relationships between fracture patterns, injury mechanisms, clinical courses, and prognoses according to the hemodynamic pattern. Methods: Between January 2004 and September 2006, 89 patients under diagnosis of pelvic bone fracture were retrospectively analyzed on the basis of medical records and radiologic examinations. Patients with confirmed hemorragic shock with a systolic pressure of less than 90 mmHg were defined as the shock group. Young's classification was used to characterize fracture patterns. Factors relating to the clinical manifestation and to treatments such as transfusion and surgery were analytically compared. Results: The mean age of the patients was $48.8{\pm}18.7$, among which 49 (55.1%) were male. The numbers of shock and non-shock patients were 35 (39.3%) and 54 (60.7%) respectively. Eighteen (51.4%) of the shock patient had injuries resulting from pedestrian accidents (p=0.008). According to Young's classification, lateral impact fractures amounted to 20 and 33, front-rear impact fractures to 9 and 20, and multiple fractures to 6 and 1 among the shock and non-shock patients, respectively (p=0.027). Thirty-nine (39) cases in non-shock injuries were conservatively managed while 18 cases in shock injuries were surgically treated. In the shock group, the liver and the kidney were often damaged, as well. Among the shock patients, the average admission period was $7.5{\pm}8.7days$ in intensive care and $55.1{\pm}47.9days$ in total, which were longer than the corresponding numbers of days for the non-shock patients (p<0.05). No deaths occurred in the non-shock group while 5 deaths (14.2%) occurred in the shock group (p=0.007). Conclusion: The factors affecting hemodynamic instability in patients with pelvic bone fracture are injury mechanism, classification of fracture, and associated injuries.

• Journal of Chest Surgery
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• 제9권1호
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• pp.20-26
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• 1976

Author has performed experimental study on hemodynamic changes of lung following radical hilar stripping and contralateral pulmonary artery ligation. In view of hemodynamic changes in group 1 (right pulmonary artery ligation only) and group 2(left hilar stripping+right pulmonary artery ligation). group 2 showed remarkable decrease rate in oxygen uptake (P<0.001) and total pulmonary blood flow(P<0.001), and the more increase rate in mean pulmonary artery pressure(P<0.02) and total pulmonary vascular resistance (P<0.001). Meanwhile, the decrease percent of left lung vascular resistance was lower than group 1(P<0.001). The hemodynamic changes in group 1 returned to control range two weeks later. In the group 2, two dogs were expired as a result of atelectasis and pulmonary hypertension. Among allying 8 dogs, five months after operation, follow up studies performed in two dogs, which showed normal pulmonary hemodynamics similar to preoperative data. The altered blood gas values and decreased oxygen uptake are more remarkable in denervated lung, which may due to pulmonary hypertension and partly retained more secretion in bronchial trees than usual. Important factors of raising pulmonary vascular resistance and pulmonary artery pressure are considered as the increased blood flow to remaining left lung and dysfunction of pulmonary vascular bed to accept the increased blood flow after denervation. Loss of nerve innervation had a influence, to some extent, to the decrease of oxygen uptake and the increase of pulmonary vascular resistance and pulmonary artery pressure. There can be little question that denervation does impair the pulmonary hemodynamics, however, intact pulmonary nerve innervation is not absolutely essential for survival of the animal.

• 대한기계학회논문집B
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• 제34권10호
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• pp.893-899
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• 2010

박동유동조건에서 관상동맥 내의 유동특성과 혈류역학적 인자 분포를 선행연구에서 수행하여 혈류역학이 관상동맥 내의 협착현상과 연관관계가 있음을 밝혔다. 동맥경화증의 호발부위인 관상동맥 분지부에서 혈류역학적 변수를 분석하여 동맥경화증의 발생기전을 규명하는 것이 본 연구의 목적이다. 동맥경화증에 의한 협착현상은 혈액과 혈관벽 사이의 생화학 반응뿐 아니라 유동박리나 벽전단응력과 같은 혈류역학적 인자와도 관계 있음을 확인하였다. 관상동맥 분지부의 분지각이 증가할수록 분지부 단면에서의 재순환영역의 크기가 증가하고 교란유동이 발생하게 된다. 이 재순환영역이 관상동맥에서 동맥경화의 시작점으로 의심되는 영역이라 할 수 있다.