• 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.

• Clinical and Experimental Pediatrics
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• v.56 no.4
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• pp.176-181
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• 2013

Purpose: Apical muscular ventricular septal defects (MVSDs), especially in small infants, can be difficult to manage using surgical and percutaneous closure. An intraoperative perventricular procedure is a good option for closing apical MVSDs in small children with or without associated cardiac anomalies. We evaluated the results of hybrid perventricular closure of apical MVSDs performed using an Amplatzer duct occluder (ADO). Methods: We retrospectively reviewed the medical records of 5 patients who underwent hybrid perventricular closure of MVSDs with ADOs, from March 2006 to May 2011. The median patient age at the time of the procedure was 12 months (range, 25 days to 25 months), and the median body weight was 9.1 kg (range, 4.3 to 15 kg). Two patients had multiple ventricular septal defects (VSDs; additional perimembranous VSD in 1 patient and multiple MVSDs in the other) and 3 patients had associated cardiac anomalies; complete transposition of the great arteries in 1 patient and an atrial septal defect in 2 patients. All the procedures were performed on beating hearts, exception in 1 case. The ADO selected for the aortic side was at least 1 to 2 mm larger than the largest VSD in the left ventricle side. Results: The procedure was successful in all patients and each device was well positioned. During the median follow-up of 2.4 years, a small residual VSD was noted in 2 patients who had multiple VSDs and no leakage was seen in the other 3 patients. Conclusion: Perventricular closure of MVSD with an ADO is a good option for patients with apical MVSD. However, careful manipulation is important, especially in the case of small infants.

• Journal of Biomedical Engineering Research
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• v.31 no.4
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• pp.316-320
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• 2010

HRV(Heart rate variability) analysis parameter is widely used as an index to evaluate the autonomic nervous system and cardiac function. For reliable HRV analysis, we need to acquire the accurate ECG signals. Most of commercially available portable ECG devices have low sampling rate because of low power consumption and small size issues, which make it difficult to measure RR-interval accurately. This study is to improve the accuracy of RR-interval by developing R-wave interpolation technique, based on the morphological characteristics of the QRS complex. When the developed method was applied to ECG obtained at 200 Hz and the results were compared with 1000 Hz reference device, the error range decreased by 1.33 times in sitting and by 2.38 times in cycling exercise. Therefore, the proposed interpolation technique is thought to be useful to improve the accuracy of R-R interval in the portable ECG device with low sampling rate.

• Journal of Chest Surgery
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• v.48 no.3
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• pp.202-205
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• 2015

Formation of an aneurysm in the sinus of Valsalva of the aortic root is usually due to an area of congenital weakness in its wall. This aneurysm may progressively dilate and rupture into any of the cardiac chambers or into the pericardial cavity. Though this is conventionally treated by surgery, interventional therapy using various closure devices is becoming more common. Embolization of these closure devices may occur. We report a case of embolization of such a device into the left pulmonary artery which during surgical retrieval, unmasked the hidden ventricular septal defect (VSD). Therefore one has to be cautious while making a diagnosis of rupture of the sinus of Valsalva of right coronary sinus without VSD.

• Journal of Chest Surgery
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• v.45 no.2
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• pp.116-119
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• 2012

A 61-year-old female patient was diagnosed with dilated cardiomyopathy with severe left ventricle dysfunction. Two days after admission, continuous renal replacement therapy was performed due to oliguria and lactic acidosis. On the fifth day, an intra-aortic balloon pump was inserted due to low cardiac output syndrome. Beginning 4 days after admission, she was supported for 15 days thereafter with an extracorporeal left ventricular assist device (LVAD) because of heart failure with multi-organ failure. A heart transplant was performed while the patient was stabilized with the LVAD. She developed several complications after the surgery, such as cytomegalovirus pneumonia, pulmonary tuberculosis, wound dehiscence, and H1N1 infection. On postoperative day 19, she was discharged from the hospital with close follow-up and treatment for infection. She received follow-up care for 10 months without any immune rejection reaction.

• Journal of Chest Surgery
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• v.20 no.1
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• pp.22-29
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• 1987

From Sep. 1978 to Aug. 1986, 44 cases of Fontan operation were performed at Seoul National University Hospital. 1] The diagnoses were TA in 13 [38.6%], UVH in 21 [47.79`], DORV in 3 [6.8%], TGA in 2 [4.5%] and C-ECD with DORY in 1[2.3%]. 2] There were 20 operative deaths [44.5%]. 3] The operative risk factors were early date of operation between 1978 and 1983, young age below 3 years old, direct atriopulmonary anastomosis without roofing, and postoperative high CVP above 25cmH,O. But the relation between operative mortality and various cardiac diseases was absent. 4] survived patients were followed from 1 to 54 months except 3 patients who were lost to follow up. 16 patients were in functional class I and 1 in class II, 2 of the above 17 patients were reoperated due to residual right to left shunt. In remained 4 patients, 3 patients persisted cyanosis after operation and 1 patients died 1 month postoperatively due to pulmonary embolism. 5] As 4 result, the Fontan procedure can be done with a good result for tricuspid atresia and other complex lesions. The operative mortality can be reduced further with a correct anatomical diagnosis preoperatively, rigid operative criteria to pulmonary vascular resistance, direct atriopulmonary anastomosis with roofing, and use of `Venous Assist Device` postoperatively in low cardiac output patients.

• Journal of Chest Surgery
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• v.25 no.12
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• pp.1550-1555
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• 1992

From June 1989 to July 1992, we used centrifugal Biomedicus pump[CBP] in 20 patients In 9 cases, CBP was used as ventricular assistance after heart surgery for those who could not be weaned off bypass even with intra-aortic balloon counter-pulsation and with maximal inotropic support In 8 patients, CBP was used as partial left heart bypass during repair of aortic aneurysms or congenital aortic anomalies. And in 3 patients, CBP was used as vena caval bypass during resection of renal cell carcinoma with tumor extension into the inferior vena cava. In 2 of 9 patients with ventricular assistance, they were weaned off the device successfully after 16 hours and 7 days respectively. But the patients died of intracranial hemorrhage and sepsis, 7 and 29 days after weaning from cardiac support, respectively. In all the patients who underwent aortic of vena caval surgery using CBP as shunt, there were no complications such as postoperative bleeding necessitating reoperation, renal failure or neurologic sequelae. In conclusion, the centrifugal type of ventricular assistance may be potentially life saving treatment modality in patients with severe postoperative low cardiac output syndrome. The CBP can be safely employed for resection of renal cell carcinoma with vena caval tumor extension and for repair of aortic aneurysms.

• Journal of Chest Surgery
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• v.26 no.6
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• pp.441-451
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• 1993

Protective effect of superoxide dismutase[SOD] and substrates on acute ischemic and reperfused myocardium was assessed by cardiac microdialysis. 30 Rabbits were divided into 4 groups; normal control group [group I, n=5], ischemic group [group II, n=5], SOD treated group [group III, n=10], and substrates treated group [group IV, n=10]. After a microdialysis apparatus was implanted in rabbit myocardium, coronary artery was occuluded for 5 minutes and reperfusion was performed for 30 minutes. Hemodynamic changes, CK-MB isoenzyme level and adenine ring compound level in effluent dialysates [equilibrated with interstitial fluid], and ultrastructural changes of myocardial cell were analysed. Systolic blood pressure at 10 and 30 minutes after reperfusion was higher in group III and IV than in group II [p<.05]. Also percent recovery of systolic blood pressure in group III [p<.01] and IV [p<.02] was higher than in group II. CK-MB isoenzyme level in effluent dialysates was peaked at 10 minutes after reperfusion, thereafter decreased in group II, III and IV. At 30 minutes after reperfusion, its level was lower in group III and IV than in group II[p<.05]. Adenine ring compound level in effluent dialysates increased till 10 minutes after reperfusion and progressively decreased. At 10 and 30 minutes after reperfusion, its level was lower in group III and IV than in group II without significance. Degree of myocardial damage was estimated by scoring of mitochondrial injury. Group I was within normal range and most severe injury was seen in group II. And the score of mitochondrial injury in group III and IV was lower than in group II. In conclusion, SOD and substrates[KMP solution] had protective effect on stunned myocardium. The microdialysis appratus was a good device for studying stunned myocardium, and cardiac microdialysis might be a unique technique for analysis of regional intramyocardial interstitial fluid.

• Journal of Chest Surgery
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• v.37 no.12
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• pp.1003-1009
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• 2004

Mechanical circulatory support (MCS) has been used for myocardium failure, but moreover, it may be essential for the life support in cardiac arrest or cardiogenic shock. Many commercial devices can be used effectively for the long-term support. However, there are some limitations in the aspects of the cost and technical support by production company. Short-term support with centrifugal type has been reported numerously with the purpose of bridging to heart transplantation or recovery. We successfully treated 5 patitents who were in the status of cardiogenic shock (n=3) or arrest (n=2) with the technique of extracorporeal life support system (ECLS) or left ventricular assist device (LVAD) using the centrifugal type pump. The MCS were performed emergently (n=2) under cardiac arrest caused by ischemic heart disease, and urgently (n=3) under cardiogenic shock with ischemic heart disease (n=1) or acute fulminant viral myocarditis (n=2). All patients were weaned from MCS. Complications related to the use of MCS were bleeding and acute renal failure, but there were no major complications related to femoral cannulations. Mechanical circulatory support may be essential for the life support and rescue in cardiac arrest or cardiogenic shock.

• The Korean Journal of Emergency Medical Services
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• v.9 no.2
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• pp.147-168
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• 2005

It examined the doubt point which AED motive relates until now, the AED should have bought a life how, present address of our country site pre-hospital care, comparison it tried to observe the advanced nation instance back. Gist of this research the AED important cold region once compared to informed to how many cardiac arrest patient, against him the what kind of preparation wanted informing the necessary cold region. It soaks simultaneously but the AED motive is widely supplied distant in future and it is generality and it is feeble but it wanted doing one morning. The habit difference of an American who does of course meat diet mainly and a Korean is many and it compares in the United States and the cardiac arrest patient comparison occurs holds a point few. To become Western anger but and be caused by with thin dietary life, stanching bleeding cung, with the fact that the heart attack is increasing rapidly with the hyperextension. It is a talk which anyone it knows all. The major league most Choi huy Sub in condition will catch the ball which floats and the multi co-player and to collide when falling down, the medical device which is committed with emergency aid is AED motive. From the United States subway station and the shopping which are a public place on the baseball field outside the jar which it will drive, the museum and the school, easily there is it will be able to discover the AED from the court of justice back. The Pittsburg university the students per the individual $30 the core phyey were receiving the smallness lifestyle alcoholic beverage and a AED motive actual training with mercy of degree. From the United States distant in future the AED motive is sold even from the retail store and. From our country like this plan government offices temporary disposal education from from 119 fire fighters emergency structure company in fire fighting government employee and nursing must magnify a former enterprise rainy spell in summer multi temporary disposal education with the head which it will burn with the head. This plan in early rising will be able to become fixed in Korea it forecasts with the fact that. The research which it sees it leads and like the United States to some day become fixed even from our country to believe and suspicion it is not and in the people in approach ease one AED supply plan fire fighting government employees stand in the first and feed with the fact that must be positive at this enterprise they become.