• Journal of Chest Surgery
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• 제27권6호
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• pp.460-471
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• 1994

Between Feb. 1990 and Aug. 1993, 180 cases of the open heart surgery were performed under cardiopulmonary bypass in the Department of Thoracic & Cardiovascular surgery, Gil General Hospital. There were 83 cases with congenital heart diseases [CHD] and 97 cases with acquired heart diseases [AHD]. The CHD consisted of 78 acyanotic[mortality: 3.8 %] and 5 cyanotic cases with heart anomaly[mortality:l case]. The AHD were 97 cases, which contained 53 valvular, 27 ischemic heart diseases, 10 aortic diseases, 5 cases with myxoma, 1 case with post-infarct VSD, and 1 case with removal of infected pacing wire in right ventricle. In the 53 valvular heart diseases, there were 45 cases with valve replacement[MVR 27, AVR 9,MVR + AVR 9] and 8 cases with valvuloplasty. The number of the implanted prosthetic valves were 53. In MVR, 25 St. Jude, 6 Sorin, 3 Carpentier-Edward and 2 Intact medical valves were used. In aortic position, 13 St. Jude, 3 Sorin and 1 Intact medical valves were applied. The operative mortality was 5.6 % [3/53]. The annuloplasty applying artificial ring was performed in 17 patients[4 cases associated with MVR] and the number of the implanted ring was 19, which included 14 Duran ring[10 mitral, 4 tricuspid] and 5 Carpentier ring [3 mitral, 22 tricuspid]. In the 27 ischemic heart diseases, there were 9 cases with left main coronary artery lesions, 7 one vessel, 5 two vessels, and 6 three vessels. Average number of anastomosis was 2.8 per patient. The operative mortality was 14.3 % [4/27]. Among the 10 patients with aortic diseases, 7 cases were aortic dissection[type A: 5, type B: 2] and 3 cases were descending thoracic aortic aneurysm. The operative morality occurred in 3 cases. The overall mortality and the operative mortality of congenital and acquired heart disease was 7.8 %, 4.8% and 10.4%, respectively.

• 대한기계학회논문집B
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• 제26권5호
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• pp.629-639
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• 2002

In-vitro flow characteristics downstream of a polyurethane artificial heart valve and a Bjork-Shiley Monostrut mechanical valve have been comparatively investigated in pulsatile flow using particle image velocimetry (PIV). With a triggering system and a time-delayed circuit the velocity distributions on the two perpendicular measurement planes downstream of the valves are evaluated at any given instant in conjunction with the opening behaviors of valve leaflets during a cardiac cycle. The regions of stasis and high shear stress can be found simultaneously by examining the entire view of the instantaneous velocity and Reynolds shear stress fields. It is known that high shear stress regions exist at the interface between strong axial jet flows along the wall and vortical flows in the central area distal to the valves. In addition. there are large stagnation or recirculation regions in the vicinity of the valve leaflet, where thrombus formation can be induced by accumulation of blood elements damaged in the high shear stress zones. A correlation between the unsteady flow patterns downstream of the valve and the corresponding opening postures of the polyurethane valve membrane gives useful data necessary for improved design of the frame structure and leaflet geometry of the polyurethane valve.

• Journal of Yeungnam Medical Science
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• 제32권2호
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• pp.106-110
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• 2015

The prevalence of pneumothorax cases among Intensive Care Unit patients who require mechanical ventilation ranges from 4%-15%. A pneumothorax remains one of the most serious complications of positive pressure ventilation. It can be diagnosed in a critically ill patient through a physical examination or radiographic studies that include chest radiographs, ultrasonography, or computed tomography scanning. However, in a critically ill patient, the diagnosis of a pneumothorax is often complicated by other diseases and by difficulties in imaging sick and unconscious patients. Although electrocardiogram changes associated with a pneumothorax have been described for many years, there has been no report of such among patients who require mechanical ventilation. In this paper, we report 2 cases of a spontaneous pneumothorax with paroxysmal supraventricular tachycardia in patients who required invasive mechanical ventilation due to acute respiratory failure.

• Journal of Chest Surgery
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• 제23권4호
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• pp.654-658
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• 1990

Between January of 1980 and December of 1989, we are encountered 121 cases of Down syndrome here at Yonsei University Medical Center. of these being endocardial cushion defect, ventricular septal defect, tetralogy of Fallot, atrial septal defect, patent ductus arteriosus and complicated anomalies. The mean age was 1 month 2 years with the sexual division at 31 males and 29 females. Among these 60 patients, 10 of them were treated trough surgical management, 8 of them being open heart surgeries, the 8 open heart surgeries are broken down as follow: 4 total correction of ECD, 2 patch repair of VSD, 1 total correction of TOF, 1 patch repair of ASD secundum. Another 2 operative management are ligation of PDA and modified Blalock - Taussig shunt of TOF. Postoperatively all patients were weaned and extubated on an artificial ventilator without any respiratory complications, and were discharged without incident.

• 대한의용생체공학회:의공학회지
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• 제10권2호
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• pp.91-93
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• 1989

We have developed a monoleaflet polymer valve as an inexpensive and viable alternative, especially for short-term use in the ventricular assist device or total artificial heart. The frame and leaflet of the polymer valve were made from polyurethane, To evaluate the hemodynamic performance of the polymer valve a comparative study of flow dynamics past a polymer valve and a St. Jude Medical prosthetic valve under physiological pulsatile flow conditions in vitro was made. Comparisons between the valves were made on the transvalvular pressure drop, regurgitation volume and maximum valve opening area. The polymer valve showed smaller regurgitation volume and transvalvular pressure drop compared to the mechanical valve at higher heart rate. The results showed that the functional characteristics of the polymer valve compared favorably with those of the mechanical valve at higher heart rate.

• 설비공학논문집
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• 제10권3호
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• pp.368-377
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• 1998

The purpose of this study was to examine theory about indoor thermal comfort-environment as well as to determine thermal sensation and physiological responses for men in summer indoor environment, under various air temperature and relative humidity, with male university students. Subjective Evaluation, Heart Rate(Electrocardiogram), Electroencephalogram(EEG) were examined. We found that comfort of people was achieved at SE $T^{*}$ 24.7$^{\circ}C$, -0.82＜PMV＜0.93, subject's clothing(0.41c1o)and the difference of skin temperature was found at the calf area as air temperature changes. At low SE $T^{*}$, heart rate was decreased and at high SE $T^{*}$, heart rate was increased but there was no change EEG(keeping $\alpha$-wave).wave).

• 대한의용생체공학회:의공학회지
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• 제16권1호
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• pp.61-66
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• 1995

We have developed a monoleaflet polymer valve as an inexpensive and viable alternative, especially for short-term use in the ventricular assist device or total artificial heart. The frame and leaflet of the polymer valve were made from polyurethane. To evaluate the hemodynamic performance of the polymer valve a comparative study of flow dynamics past a polymer valve and a St. Jude Medicals prosthetic valve under physiological pulsatile flow conditions in vitro was made. Comparisons between the valves were made on the transvalvular pressure drop, regurgitation volume and maximum valve opening area. The polymer valve showed smaller regurgitation volllme and transvalvular pressure drop compared to the mechanical valve at higher heart rate. The results showed that the functional characteristics of the polymer valve compared favorably with those of the mechanical valve at higher heart rate.

• Bulletin of the Korean Chemical Society
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• 제19권2호
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• pp.160-164
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• 1998

The NADH-cytochrome b5 reductase (NCBR), a mitochondrial external electron carrier, was purified from bovine heart and turnip and their properties were examined. The mitochondrial outer membranes separated were subjected to NCBR isolation through DEAE-Cellulose ion exchange, DEAE-Sephadex gel chromatography, and hydroxyapatite adsorption chromatography. These processes yielded the purification folds of 88 and 42 and the recovery percentages of 0.2%, 5.67% for turnip and bovine heart, respectively. The molecular weight of the NCBR from the two sources was estimated to be 35,000 using SDS polyacrylamide gel electrophoresis. The Michaelis constant Km and maximum velocity Vmax were determined by measuring the NADH-ferricyanide redox system as well as the NADPH-ferricyanide redox system. The kinetics showed that both NCBRs had higher affinities for NADH than artificial electron-acceptor substrate ferricyanide. Although NADPH had a lower affinity for the enzymes than NADH, this study showed the 2'-phosphate dinucleotide could be used as a substrate.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1992년도 춘계학술대회
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• pp.193-197
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• 1992

• 대한흉부심장혈관외과학회:학술대회논문집
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• 대한흉부외과학회 1993년도 제25차년차학술대회 및 총회
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• pp.119-119
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• 1993