• Journal of Chest Surgery
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• v.34 no.4
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• pp.365-367
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• 2001

매우 드물게 발생하지만 대동맥판막수술중에 우관상동맥의 급성폐색은 우심실부전을 일으켜 매우 치명적인 결과를 초래할 수 있다. 심한 대동맥 판막부전증을 가진 67세 여자 환자에서 19 mm Hancock II 조직판막을 이용하여 대동맥판막치환술을 시행한 후 심폐기에서 이탈하는 과정주에 우심실부전이 발견되었으며, 우관상 동맥의 폐색을 의심하여 우측 내흉동맥을 사용하여 관상동맥 우회수술을 시행하였고 이후에 심폐기에서 순조롭게 이탈할 수 있었다. 수술후 9일째 시행한 관상동맥 조영술에서 우관상동맥 근위부에 색전에 의한 폐색을 확인할 수 있었다. 이에 저자들은 우관상동맥의 폐색으로 인한 우심부전증이 우관상동맥우회수술후에 회복된 증례를 보고하고자 한다.

• Solar Energy
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• v.20 no.1
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• pp.63-72
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• 2000

In this study, theoretical simulation method for the steady state characteristics of a refrigeration cycle which consists of one condenser and multi-evaporator (Multi-air conditioner) is presented. The simulation was performed for a typical multi-air conditioning system consisted one outdoor unit with air-cooled condenser, compressor, linear electric expansion valve and bypass circuit and connected three-evaporators (three indoor units). The simulation results are good agreement with those of experiments within 5 $\sim$ 10% at the given system operation conditions which are condensing pressure, evaporating pressure, sub-cooled degree of condenser, superheated degree, discharge temperature of compressor and pulse of linear electric expansion valve.

• Journal of Chest Surgery
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• v.54 no.6
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• pp.554-557
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• 2021

Surgeons are increasingly using the right mini-thoracotomy approach to perform aortic valve surgery. This approach has shown better results in terms of blood loss and length of hospital stay than the sternotomy approach. For selected patients requiring aortic root and ascending aorta surgery, a right mini-thoracotomy approach may prove beneficial. In our technique, we placed a 5-cm horizontal skin incision in the right second intercostal space. Femoro-femoral cardiopulmonary bypass was established. A valved aortic conduit was used for aortic root replacement. The patient's postoperative course was uneventful, with a short hospital stay. This technique offers a minimally invasive approach to aortic root and ascending aorta surgery with easy adaptability and reduced costs.

• Journal of Chest Surgery
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• v.26 no.5
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• pp.403-408
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• 1993

The atrioventricular node reentrant tachycardia[AVNRT] is a common type of supraventricular tachycardias. Recently we experienced two cases of AVNRT. One is AVNRT with severe aortic regurgitation[grade IV] and the other is AVNRT with patent ductus arteriosus. Dissection of perinodal tissue has been successfully carried out in the beating heart under the normothermic cardiopulmonary bypass, and aortic valve replacement and ligation of patent ductus arteriosus were also performed, respectively. Postoperatively, permanent atrioventricular block was not occured and AVNRT was not developed during the follow up. We propose that the surgical dissection of perinodal tissue is a simple and effective treatment for the patient with refractory AVNRT.

• Journal of Chest Surgery
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• v.27 no.7
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• pp.624-627
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• 1994

Congenital coronary arteriovenous fistula is a rare cardiac defect that causes coronary arterial flow to drain into the right cardiac chambers, the pulmonary artery, the coronary sinus, or the left cardiac chambers. The most frequently involved vessel is the right coronary artery. We experienced a case that had a coronary arteriovenous fistula associated with valvular heart disease. With the cardiopulmonary bypass done under hypothermia, mitral valve replacement was accomplished and the fistulas of both proximal and distal portions of the right coronary artery were closed with 3-0 prolene. Postoperative course was uneventful.

• Journal of Chest Surgery
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• v.14 no.4
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• pp.403-407
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• 1981

Thirty-five cases of heart disease were operated on with cardiopulmonary bypass between November, 1980 and September, 1981. 1. There were 8 cases of congenital anomaly and 17 cases of acquired heart diseases. 2. There were 7 male and ] 8 female patients, with a mean age of 21 .9 years [range 7 to 42 years]. 3. There were 2 cases of valve replacement cases with operative mortality of 8.3%. 4. Operative mortality for congenital anomaly was ~ 6.7% and 5.9% for acquired heart diseases. 5. Over all operative mortality was 11.4%.

• Journal of Chest Surgery
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• v.12 no.1
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• pp.50-55
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• 1979

The development of aortic insufficiency radically alters the physical findings which are generally associated with ventricular septal defect that was not hemodynamically significant, and the combination of the two lesions produces a typical clinical picture, that may be serious and life-threatening when it is left untreated. Therefore, the selection of patients, type and timing of surgical treatment is considered to be important. Among 114 cases of ventricular septal defect treated surgically utilizing cardiopulmonary bypass in the Department of Thoracic Surgery, Seoul National University Hospital, 7 cases were associated with aortic insufficiency. 1. Five cases were male, and 2 cases were female. Ages were from 4 years to 24 years, and mean age was 11.9 years. 2. In all cases, ventricular septal defect was closed with Teflon patch. In a case, a aortic valvuloplasty and in another, a aortic valve replacement with Hancock valve 23 mm., 5 months after the closure of ventricular septal defect were done. 3. Four cases were type I ventricular septal defect by Kirklin`s classification, 3 cases were type II ventricular septal defect, and diameters of ventricular septal defect were from 3.5 cm. to 0.7 cm. A PDA. was combined to a type I ventricular septal defect. 4. In 5 cases, herniation of the aortic cusp through the ventricular septal defect and in a case, annulus dilatation on the aortic valve was noted. 5. Two cases with type I ventricular septal defect and severe pulmonary hypertension expired. A re-opened case with type II ventricular septal defect expired. 6. Four cases were alive, and all of them show decrease of pulse pressure and aortic insufficiency.

• Clinical and Experimental Pediatrics
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• v.57 no.1
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• pp.19-25
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• 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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.1
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• pp.38-42
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• 2017

This study proposes an idea for energy saving in apartment machine rooms. A conventional district heating system is equipped with constant-flow pumps and bypass valves to regulate pump differential pressure. Each family unit is equipped with a constant-flow on/off valve. This leads to excessive hot water circulation and a high return temperature. To reduce energy loss, this study assumes that each family unit is renovated with a heating valve which regulates the return temperature at $35^{\circ}C$. The hot water supply pump is also replaced with a pump with an inverter to vary flow rate. Expected energy savings is then estimated from field test data. According to the results, pump electricity consumption was reduced by 6,100 kWh for a family unit building over about half a year. The supply temperature can also be lowered by $5^{\circ}C$, which can contribute to a production of electricity of 10.3 kWh/ton of hot water.

• Journal of Biomedical Engineering Research
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• v.36 no.6
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• pp.264-270
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• 2015

A mock circulatory loop system has been developed to construct a simulator for trainees in cardiopulmonary bypass systems or to simulate a test environment for cardiac-assist devices. This paper proposes a computerized mock circulatory loop system whose node is modularized by using a servo control flow regulator to simulate dynamic change of the hemodynamic status. To observe the effect of time-varying resistance, one with hemodynamic properties, the proposed system replicates the planned cross-sectional areas of the outlet of a ventricular assist device in terms of voltage input of a servo valve. The experiment is performed (1) for steady-input commands of selected area sizes and (2) for dynamic commands such as monotonous increase and decrease, and oscillatory functions of the voltage input, and a computer program based on LabVIEW (National Instruments, Austin, USA) processes every measured data and control command to the servo valve. The results show that the pressure and flow at the target points with respect to time-varying resistance match intuitive estimation: the pressure at the outlet and the pressure drop between both sides of the valve increased and the flow at the outlet decreased for increased resistance.