• Journal of Chest Surgery
• /
• 제30권4호
• /
• pp.383-389
• /
• 1997

1992년 3월부터 1996년 3월까지 부천 세종병원에서는 총 279례의 관상동맥 우회로 조성수술을 시행 하였는 바, 이중에서 좌심실 박출계수가 35%이하인 22명의 심한 좌심실 기능저하를 동반한 환자들을 대상으로 관상동맥 우회로 조성수술의 조기 성적을 분석해 보았다. 대상 환자들의 연령은47세에서 73 세까지로 평균 60: 5.6세였고, 이중 남자는 17명, 여자는 5명이었다. 모든 환자는 수술전 흉통을 가지고 있었는데, Canadian 분류로 class ll가 6명 class 111가 12명, class IV가 4명 이 었다. 1명을 제외하고 모두 1 차례 이상의 사전 심근경색의 병력이 있었다. 운동시 호흡곤란및 방사선상폐울혈 소견 같은 심부전 증 세를 가진 사람은 7명이었다. 혈관 조명술상에서의 area-length method를 이용한 좌심실 박출계수는 18 에서 35%사이로 평균 29.4$\pm$4:5%였고, 좌심실의 확장기말 압력은 10에서 42mmHg사이로 평균 18.7$\pm$ 8.2mmHg였다. 미국 심장학회 기준에 의한 좌심실 분절운동을 살펴보면 모든 환자가 적어도 3개 분절이 상에서 운동 저하의 소견을 보였다. 1명의 2혈관 질환 환자를 제외하고 모두 3혈관 질환 환자로 관상동 맥 침범의 정도가 심하였다. 梔珦\ulcorner모든 병변이 있는 부위에 완전 재관류를 시도하였다. 내유동맥 16 개, 대복재정 맥 60개, 요골동맥 3개등 총 79개의 이식편을 사용하여, 평균 3.5$\pm$1.1회의 원위부 문한을 시행하였다. 승모판파 폐쇄부전증을 동반한 환자 4명중 1명 에서는 승모판막윤 성형술도 함께 시 행하였 다. 수술사망은 1명에거 발생하였으며(4.5%), 사망원인은 수술 전후 심근경색에 의한 저심박출증이었다. 술후 IABP는 모두 7례에서 사용하였고, 평균사용시간은 50.3$\pm$ 16.4시간이 었다. 수술 생존자중 2명은 술 후 계속되는 심부전증과 추가 심근경색으로 술후 16개월 및 22개월째 사망하였고, 나머지 1명은 뇌 경색 증 및 패혈증으로 술후 8개월째 사망하였다. 18명의 생존자중 술후 24개월과 27개월후에 추적 도중 탈 락된 2명을 제외하고 나머지 16명은 6개월엔서 47개월사이로 평균 30.4$\pm$ 13.4개월 추적 조사를 받고 있 다. 이들중 1명 에서만 총통이 재발하였고 다른 환자에서는 흉통이 사라졌다. 이들의 기능상태를 NYHA 기준에 따라 분류하면 class I이 8명, class ll가 7명 , class 111가 1명이었다. 이 연구 결과, 관상동맥 우회로 조성수술은 심한 좌심실 기능 저하를 동반\ulcorner 환자$\circledcirc$서도 비교적 납득 할 만한 위험도로 시행될 수 있으며 협심증의 완화 및 소멸에는 효과적이나, 심부전 증세의 호전에는 크 게 기여하지 않음을 알 수 있다.

• Journal of Chest Surgery
• /
• 제37권7호
• /
• pp.547-552
• /
• 2004

최근 들어 심부전증을 치료하기 위한 새로운 방법으로 골수줄기세포를 심근에 이식하여 신생혈관을 생성하거나 새로운 심근 생성을 조장하여 심장기능을 개선시키려는 노력이 활발히 진행되고 있다. 저자들은 심근경색 후 심근의 기능이 저하된 환자에서 심장박동 상태에서 관상동맥우회술 (OPCAB)과 우회술이 불가능한 부위의 골수줄기세포 이식을 동시에 시행한 연구결과를 보고하고자 한다. 대상 및 방법: 관상동맥우회술과 골수줄기세포 이식을 동시에 시행 받았던 4명의 남자 환자를 대상으로 하였다 대상 환자의 평균연령은 58세(48∼73세)로 모두 불안정성 협심증으로 심근경색의 기왕력이 있었다. 환자의 장골에서 골수를 채취한 후 단핵세포만을 분리하였으며(평균 세포 수 1.5 ${\times}$ $10^{9}$ 개), 이 중에는 평균 6.7${\times}$$10^{6}$ CD34 + 세포와 3.7 ${\times}$ $10^{6}$ AC133 + 세포가 포함되었다. 분리된 단핵세포는 10 cc로 농축하였다. 수술은 관상동맥우회술이 가능한 좌전하행지 부위에는 OPCAB을 시행하고, 나머지 우회로술이 불가능한 심근에는 분리한 단핵세포를 이식하였다. 이식 전 모든 환자는 심초음파, MIBI scan 및 자기공명영상(MRI)으로 심근의 기능을 검사하였다. 수술 후 1개월에 심초음파 및 MIBI scan을 시행하여 수술 전과 비교하였다 결과: 평균 이식편수는 2개였으며, 수술 후 사망이나 부정맥 등 합병증은 없었다. 수술 후 1개월 추적검사에서 모든 환자의 증상은 호전되었으며, 심초음파상에서 좌심실 박출계수는 49%에서 55%로 개선되었고, MIBI scan에서 세포이식 부위의 현저한 관류 개선이 모든 환자에서 있었다. 결론: 심장박동 상태에서 관상동맥우회술(OPCAB)과 우회술이 불가능한 부위에 골수줄기세포 이식을 동시에 시행하는 것은 안전하면서도 심장기능의 개선을 보여주었다. 그러나 심장기능의 개선이 골수줄기세포 단독의 효과라고 단정하기는 어려우며, 따라서 대조군을 이용한 연구가 이어져야 할 것으로 생각된다.

• Journal of Electrical Engineering and Technology
• /
• 제12권2호
• /
• pp.612-620
• /
• 2017

Relay coordination in power system is a complex problem and so far, meta-heuristic algorithms and other methods as an alternative approach may not properly deal with large scale relay coordination due to their huge time consuming computation. In some cases the relay coordination could be unachievable. As the urgency for a proper approach is essential, in this paper an innovative and simple relay coordination method is introduced that is able to be applied on optimization algorithms for relay protection coordination. The objective function equation of operating time of relays are divided into two separate functions with less constraints. As the analytical results show here, this equivalent method has a remarkable speed with high accuracy to coordinate directional relays. Two distribution systems including directional overcurrent relays are studied in DigSILENT software and the collected data are examined in MATLAB. The relay settings of this method are compared with particle swarm optimization and genetic algorithm. The analytical results show the correctness of this mathematical and practical approach. This fast coordination method has a proper velocity of convergence with low iteration that can be used in large scale systems in practice and also to provide a feasible solution for protection coordination in smart grids as online or offline protection coordination.

• Journal of Chest Surgery
• /
• 제12권4호
• /
• pp.355-360
• /
• 1979

Mitral and aortic valve replacement with tricuspid annuloplasty was undertaken in 5 patients out of 38 valvular surgery between the period from Jan. 1977 to May 1979 in the Dept. of Thoracic and Cardiovascular Surgery in Korea University Hospital. All were male patients with age ranging from 18 to 42 years, and preoperative evaluation revealed one case in Class IV, and four cases in Class III according to the classification of NYHA. Preoperative diagnosis was confirmed by routine cardiac study including retrograde aorto- and left ventriculography, and there were two cases with MSi+ASi+Ti, two cases with MSi+Ai+Ti, and one case with Mi+Ai+Ti. Double valve replacement was performed under the hypothermic cardiopulmonary bypass with total pump time of 247 min. in average ranging from 206 min. to 268 min. During aortic valve replacement, left coronary perfusion was done in the first two cases, and cardiac arrest with cardioplegic solution proposed by Bretschneider was applied in the remained three cases. Starr-Edwards, Bjork-Shiley prosthetic valves and Carpentier-Edwards tissue valve were replaced in the aortic area, and Carpentier-Edwards and Angell-Shiley tissue valves were replaced in the mitral area with each individual combination [three prosthetic and two tissue valves in the aortic, and five tissue valves in the mitral area respectively]. Postoperative recovery was uneventful in all cases except one case with hemopericardium, which was managed with pericardiectomy on the postoperative 10th day in good result. Follow-up after double valve replacement of the all five cases for the period from 6 months to 33 months revealed satisfactory adaptation in social activity and occupation with cardiac function of Class I according to the classification of NYHA In all five cases.

• Journal of Chest Surgery
• /
• 제23권6호
• /
• pp.1049-1056
• /
• 1990

The OXYREX hollow fiber membrane oxygenator developed by joint work of KIST and Green Cross Medical company has been evaluated by experimental investigation and clinical application, In this oxygenator gas exchanges occur through small pores of 0.1pm size which are distributed on 70% of surface of polypropylene hollow fiber. The Oxyrex membrane oxygenator consists of 36 thousand hollow fibers and it has 3.3m2 of gas exchange surface. The Oxyrex membrane oxygenator has unique blood flow path: blood enters the oxygenator passes between the hollow fibers and exits through outlet ports, that provides low transmembrane pressure drop. In the animal experiment and in vitro investigations of Oxyrex oxygenator, it showed low transmembrane pressure difference, effective heat exchanger performance, stable gas transfer function and less blood trauma. The Oxyrex oxygenator been used from March, 1990, to October, 1990, in 40 patients undergoing open heart operations. In the clinical applications of Oxyrex, adequate oxygenation[PaO2, 283$\pm$70mmHg] and carbon dioxide removal[PaCO2, 27\ulcorner6mmHg]were maintained under the condition of FiO2: below 0.6, Hct; 25%, perfusion flow; 2.4 L/min, gas flow: 2.1 L/min. During maximum 365 minutes of cardiopulmonary bypass[CPB] time period, the Oxyrex oxygenator maintained stable condition of PaO2, PaCO2 respectively and it also kept low plasma hemoglobin level. The complement proteins C3 and CH50 were not significantly changed pre to post CPB. There were no complications related to the oxygenator during and after the CPB.

• Journal of Chest Surgery
• /
• 제33권1호
• /
• pp.88-95
• /
• 2000

Pulmonary lymphangioleiomyomatosis is a chronic destruct8ive disease of the lung affecting women of childbearing ages which eventually leads to respiratory failure. Lung transplantation is the only conclusive therapeutic measure because this disease responds poorly to other therapies, To date only a few reports in the literature describes the clinical experience of the bilateral sequential lung transplantation of this rare condition. We performed a bilateral sequential lung transplantation on a 32-year-old woman suffering from lymphangioleiomyo-matosisw. The heart-lung block was harvested from a 51-year-old donor. We transplanted the left lung first through the clam-shell incision. As the hemodynamics deteriorated suddenly during the dissection of the right lung the right lung was transplanted under the cardio-pulmonary bypass. Although the patient's lung function was initially satisfactory the patient died of sepsis and subsequent cardiogenic shock at the postoperative 18th day. Autopsy findings showed infection of Candida albicans on the pericardium and the left lung which had been initiated possibly from the left bronchial anastomosis site,. Through detailed review of the clinical course we concluded that lung transplantation could have been performed safely on this disease provided that early diagnosis and proper management or the oppor-tunistic infection have been carried out.

• 약학회지
• /
• 제35권1호
• /
• pp.45-60
• /
• 1991

lonophores, uniquely, create specific pathways of ion permeability in model and cell membranes. Calcium-transporting ionophores of microbiological origin, such as A23187 and ionomycin, have been used as experimental tools to elucidate the physiological role of calcium as a second messenger in many cell types. These ionophores are believed to bypass the initial ligand-receptor step in the activation of cells by increasing membrane permeability to calcium. In this report, we shall discuss several naturally occurring substances that share some properties of calcium-ionophores, primarily concentrating on oxidized fatty acids. We have previously demonstrated that oxidized linoteic and arachidonic acids, obtained either by lipoxygenase catalysis or nonenzymatic processes, significantly promote calcium translocation in a two-phase partition model and modulate calcium-transporting function in the isolated sarcoplasmic reticulum vesicles obtained from mammalian hearts. We have also confirmed that calcium-ionophoric properties are due not to their general amphiphilic nature of certain lipids, but to distinct structural characteristics. Although there are some skeptical views on the occurrence of ionophores in higher organisms, increasing evidence suggests that membrane lipids or their derivatives may serve as physiological calcium-ionophores. Abnormal accumulation of lipid peroxidation products(particularly end products), however, may be associated with the general oxidative damages as seen in many pathological conditions.

• Clinical and Experimental Pediatrics
• /
• 제57권1호
• /
• pp.19-25
• /
• 2014

Recently, surgical outcomes of repair of tetralogy of Fallot (TOF) have improved. For patients with TOF older than 3 months, primary repair has been advocated regardless of symptoms. However, a surgical approach to symptomatic TOF in neonates or very young infants remains elusive. Traditionally, there have been two surgical options for these patients: primary repair versus an initial aortopulmonary shunt followed by repair. Early primary repair provides several advantages, including avoidance of shunt-related complications, early relief of hypoxia, promotion of normal lung development, avoidance of ventricular hypertrophy and fibrosis, and psychological comfort to the family. Because of advances in cardiopulmonary bypass techniques and accumulated experience in neonatal cardiac surgery, primary repair in neonates with TOF has been performed with excellent early outcomes (early mortality<5%), which may be superior to the outcomes of aortopulmonary shunting. A remaining question regarding surgical options is whether shunts can preserve the pulmonary valve annulus for TOF neonates with pulmonary stenosis. Symptomatic neonates and older infants have different anatomies of right ventricular outflow tract (RVOT) obstructions, which in neonates are nearly always caused by a hypoplastic pulmonary valve annulus instead of infundibular obstruction. Therefore, a shunt is less likely to preserve the pulmonary valve annulus than is primary repair. Primary repair of TOF can be performed safely in most symptomatic neonates. Patients who have had primary repair should be closely followed up to evaluate the RVOT pathology and right ventricular function.

• Journal of Chest Surgery
• /
• 제26권10호
• /
• pp.743-748
• /
• 1993

Alterations in thyroid function test results are frequently seen in patients with nonthyroidal illness & correlate with the severity of the illness & prognosis. We studied thyroid hormone changes in 14 patients received cardiopulmonary bypass[CPB]. All patients were biochemical euthyroidism preoperatively. TSH[Thyroid Stimulating Hormone] level reached its nadir[0.46 $\pm$ 0.11 ulU/ml, P<0.0005] at 12 hours after the start of CPB & showed elevating pattern to the preoperative level thereafter. FT4[Free Thyroxine] reached to its nadir[10.16$\pm$ 1.17 pmol/L, P<0.01] at POD[Post Operative Day] #4 & reached to the preoperative level at POD #7. Mean serum TSH & FT4 concentration were within normal limits[P>0.25] during CPB & thereafter. TT3[Total Triiodothyronine] reached to its nadir[38.6 $\pm$ 8.4 ng/dl, P<0.001] at 30 minutes after the start of CPB & remained low[P<0.05] throughout the study period. The patients whose recovery was uneventful[Group I] had higher serum TSH, TT3 levels[P<0.05] than who had complications or died[Group II]. Group I showed the elevating pattern of TSH, TT3 at POD #4, but Group II failed to show such elevating pattern. In Group I, FT4 was within normal limits[P>0.5] throughout the study period, and also within normal limits[P>0.1] in Group II.

• Environmental Engineering Research
• /
• 제25권3호
• /
• pp.366-373
• /
• 2020

The autonomous vehicles (AVs) could make a positive or negative impact on reducing mobile emissions. This study investigated the changes of mobile emissions that could be caused by large-scale adoption of AVs. The factors of road capacity increase and speed limit increase impacts were simulated using a conceptual modeling approach that combines a hypothetical speed-emission function and a traffic demand model using a virtual transportation network. The simulation results show that road capacity increase impact is significant in decreasing mobile emissions until the market share of AVs is less than 80%. If the road capacity increases by 100%, the mobile emissions will decrease by about 30%. On the other hand, driving speed limit increase impact is significant in increasing mobile emissions, and the environmentally desirable speed limit was found at around 95 km/h. If the speed limit increases to 140 km/h, the mobile emissions will increase by about 25%. This is because some vehicles begin to bypass the congested routes at high speeds as speed limit increases. Based on the simulation results, it is clear that the vehicle platooning technology implemented at reasonable speed limit is one of the AV technologies that are encouraging from the environmental point of view.