• Journal of Chest Surgery
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• v.38 no.8 s.253
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• pp.557-563
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• 2005

Background: Recently 980-nm diode laser endovenous treatment was introduced and used as a method of treatment for varicose vein in lower extremities. The advantages of endovenous laser treatment are good cosmetic effects without incision and avoidance of complications associated with surgery. Therefore, we performed an endovenous laser treatment using a 980-nm diode laser and observed the effects and the efficiency of treatment. Material and Method: From October, 2003 to March, 2004, 55 patients (84 limbs) underwent endovenous laser treatment with a 980-nm diode laser. The effects of treatment, complications and recurrences were reviewed. Result The mean age of patients was 47.2 years old and the number of men and women were 2f and 35. In a total of 84 limbs, postoperative complications were transient ecchymosis(84 cases), local paresthesia (24 cases), local skin discolorization (6 cases), minimal burn (3 cases), and post operative phlebitis (1 cases). Adjuvant sclerotherapy was performed in 27 limbs and it was performed in varicose veins missed at operation and varicose veins remaining after endovenous laser treatment. In a total of 56 patients, 2 patients $(3.57\%)$ had recurrences after endovenous laser treatment and were treated with phlebectomy. Conclusion: Our findings demonstrated that 980-nm endovenous laser treatment had good cosmetic results with acceptable complications. This study was based on short-term results and long term follow-up is necessary to evaluate the accurate effects of treatment and recurrence. We think that multimodality treatment with endovenous laser treatment including phlebectomy or transilluminated powered phlebectomy can help decreasing of recurrence especially in patients with tortuous varicose cluster.

• Journal of Chest Surgery
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• v.32 no.5
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• pp.442-447
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• 1999

Introduction: Understanding the normal distribution of the tracheal diameter and crross- sectional area is one of the key elements in the management of various tracheal pathologies or tracheal reconstruction for the patients in growing age. However, data for Korean standard has been lacking. This study was designed to analyze retrospectively the distribution of tracheal diameter and cross-sectional area in young Koreans, which can afford fundamental data for the management of tracheal diseases. Material and Method: Of the patients who underwent computerized tomogram of the chest between May 1996 and August 1998, one hundred six young patients(age range: 0-20 years) were included. Patients with any conditions which might affect the tracheal cross-sectional area or diameter, such as tracheal disease, previous operation, mediastinal tumor, or obstructive lung disease were excluded from the study. Gender distribution was 69 males and 37 females. Tracheal diameters, anterior-posterior and transverse, were measured at the level of the thoracic inlet(level I) and the aortic arch(level II). Types of the trachea were divided into round, oval, or horseshoe shaped on cross-sectional view, and the dimension was calculated by using the equation of A=1/4$\pi$ab(A; area, $\pi$; 3.14, a; anterior-posterior diameter, b; transverse diameter). We analyzed the distribution of the diameter at each level and compared the cross-sectional area with respect to age and gender. A p-value lower than 0.05 wa considered significant. Result: The trachea of patients less than 5 years old were round in shape at both of level I and II, and no differences in cross-sectional area was observed between the levels(p=NS). As the age increased, the trachea become oval in shape at level I while it remained round in shape at level II(p=0.020). The tracheal diameter and cross-sectional area increased as the age increased with a linear correlation(r>0.9). In patients less than 5 years of age, female patients showed larger cross-sectional area than male patients (p=0.020), and it was reversed in patients older than 15 years of age(p=0.002). Conclusion: From the above results, we suggest chest computerized tomogram as a safe and reliable tool in measuring the tracheal diameter and cross-sectional area. We also provide the data as a standard for distribution of the tracheal diameter and cross-sectional area in young Korean population.

• Journal of Chest Surgery
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• v.36 no.3
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• pp.142-149
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• 2003

To know the feasibility of the coronary artery bypass graft (CABG) for multivessel coronary artery disease with purely bilateral internal thoracic arteries (ITAs), we analyzed the short-term clinical results and the coronary angiography of the patients. Material and Method: From March 2001 to June 2002, four hundred and five patients underwent CABG. Purely bilateral ITAs were used in 159 patients (39.3%). We analyzed these patients retrospectively The mean age of these patients was $61.2{\pm}8.5$ (range: 30 ~80) years and there were 123 male patients. The preoperative risk factors were as follows: diabetes in 54 patients (34.0%), history of acute myocardiac infarction within 4 weeks in 29 (18.2%), and emergency operation in 6 (3.8%). Off-pump CABG was carried out in 128 patients (80.5%). Associated procedures were mitral valvuloplasty (5), aortic valve replacement (3), Dor procedure (1), and so on. Result: The mean number of distal anastomoses was $3.1{\pm}0.9$ (range: 2~6), the mean duration of hospital stay was $8.4{\pm}4.5$ days. There was one (0.6%) operative death. Except for one early death, no other patients suffered from low cardiac output. The other postoperative complications were occurred as follows: reoperation due to bleeding in 3 patients, perioperative myocardiac infarction in 1, transient cardiac arrest in 2, transient cognitive dysfunction in 7, and transient ischemic attack in 1, and deep sternal wound infection in 1 patient. Recently, early postoperative angiography was performed in 19 patients who had triple vessel disease. The total number of distal anastomosis was 78 (mean $4.1{\pm}0.8$/patient). All distal anastomosis sites were patent, but competition flow was observed at the bypass sites where the native coronary artery stenosis was not significant. Conclusion: The CABG with purely bilateral ITAs for triple vessel disease was performed safely. The early patency rate was relatively good in small number of patients. However the long-term patency rate and the functional study to evaluate the sites where competition flow was observed should be followed.

• Journal of Chest Surgery
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• v.36 no.9
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• pp.646-650
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• 2003

Many surgical techniques for ischemic mitral regurgitation (IMR) have been used with their excellent results and advantages. Here, we report our simple posterior annuloplasty techniques using vascular graft strip with their early results. Material and Method: Twenty two patients (13 male) underwent the operations for IMR (excluding the papillary muscle rupture) from December 2001 to January 2003. Preoperative risk factors were low ejection fraction (<35％, n=9), hypertension (n=13), diabetes (n=9), and renal failure (Cr>2.5, n=4). The wide dissection beneath the both vena cavae and interatrial groove after bicaval cannulation enabled the easy exposure of mitral valve even in the small left atrium. After eight or nine interrupted sutures in posterior annulus for anchoring the 6 mm width vascular graft strip, symmetric (n=8) or asymmetric (n=14) annuloplasty were done. Combined surgeries were CABG (n=21), Dor procedures (n=3), tricuspid valve annuloplasty (n=1), Maze operation (n=1), and aorto-right subclavian artery bypass (n=1). Result: Except for one surgical mortality, all the patients were doing well and the mean grade of regurgitation was decreased from 2.95 to 0.88, however the ejection fraction had not changed significantly just before discharge. Post-operative valve function evaluated before discharge revealed no residual regurgitation in 8 (including 1 patient with mild stenosis due to over reduction), minimal in 11, mild in 2, and mild to moderate regurgitation in 1. One patient who had ischemic cardiomyopathy and renal failure died of the arrhythmia during the hemodialysis. Conclusion: These observations suggest that the annuloplasty with vascular graft strip could be a safe and cost effective techniques for ischemic mitral regurgitation. However, the long term evaluation for the mitral valve function should be defined for the final conclusion.

• Journal of Chest Surgery
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• v.37 no.9
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• pp.749-754
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• 2004

Off-pump coronary artery bypass grafting (Off-Pump CABG) has been proven to have less morbidity and to facilitate early recovery. High-risk surgical patients may have benefitted by avoiding the adverse effects of the cardiopulmonary bypass. We compared the effectiveness of Off-Pump CABG with that of coronary artery bypass using cardiopulmonary bypass (On-Pump CABG) in high-risk patients. Material and Method: 682 patients (424 Off-Pump CABG and 258 On-Pump CABG) underwent isolated coronary artery bypass grafting between January 2001 and June 2003. Patients who were considered high risk were selected High risk is defined as the presence of one or more of nine adverse prognostic factors. Data were collected from 492 patients in Off-Pump CABG and 100 in On-Pump CABG for risk factors, extent of coronary disease, and in-hospital outcomes. Result： Off-Pump CABG group and On-Pump CABG group did not show differences in their preoperative risk factors. We used more arterial grafts in Off-Pump CABG group (p < 0.05). Postoperative results showed that operative mortality (0.5% in Off-Pump CABG versus 2.0% in On-Pump CABG), renal failure (2.6% in Off-Pump CABG versus 7.0% in On-Pump CABG), and perioperative myocardial infarction (1.5% in Off-Pump CABG versus 1.0% in On-Pump CABG) did not differ significantly. However, Off-Pump CABG had shorter mean operation time (p<0.05), lower mean CK-MB level (p <0.05), lower rate of usage of inotropics (p < 0.05), shorter mean ventilation time (p <0.05), lower perioperative stroke (0% versus 2.0%), and shorter length of stay (p < 0.05) than On-Pump CABG. On-Pump CABG had more distal grafts (p<0.05) than Off-Pump CABG. Although Off-Pump CABG and On-Pump CABG did not show statistical differences in mortality and morbidity was more frequent in CABG. Conclusion: Off-Pump CABG reduces morbidity and favors hospital outcomes. Therefore, Off-Pump CABG is safe, reasonable and may be a preferable operative strategy for high-risk patients.

• Clean Technology
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• v.17 no.1
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• pp.69-77
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• 2011

The intrinsic $CO_2$ separation and hydrogen production system is a novel concept using oxidation and reduction reactions of oxygen carrier for both $CO_2$ capture and high purity hydrogen production. The process consists of a fuel reactor (FR), a steam reactor (SR) and an air reactor (AR). The natural gas ($CH_4$) is oxidized to $CO_2$ and steam by the oxygen carrier in FR, whereas the steam is reduced to hydrogen by oxidation of the reduced oxygen carrier in SR. The oxygen carrier is fully oxidized by air in AR. In the present study, the chemical looping moving bed reactor having 200 L/h hydrogen production capacity is designed and the hydrodynamic properties were determined. Compared with other reactors, two moving bed reactors (FR, SR) were used to obtain high conversion and selectivity of the oxygen carrier. The desirable solid circulation rates are calculated to be in the range of $20{\sim}100kg/m^2s$ from the conceptual design. The solid circulation rate can be controlled by aeration in a loop-seal. To maintain the gas velocity in the moving beds (FR, SR) at the minimum fluidization velocity is found to be suitable for the stable operation. The solid holdup in moving beds decrease with increasing gas velocity and solid circulation rate.

• Clinical and Experimental Pediatrics
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• v.52 no.12
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• pp.1364-1369
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• 2009

Purpose : To analyze abnormal ventricular activation in childhood congenital heart disease induced by postoperative changes in ventricular volume and pressure and ventricular scar formation using signal-averaged electrocardiography (SAECG). Methods : Fifty-two patients who had undergone open heart surgery (OHS) were enrolled. Patients were divided into the following 3 groups: right ventricular volume overload (atrial septal defect, group1), left ventricular volume overload (ventricular septal defect, group2), and right ventricular pressure overload (tetralogy of Fallot, group 3). The patients were monitored by standard 12-lead ECG and SAECG before and 2 months after the operation. QRS duration, QT and QTc intervals, filtered QRS (f-QRS), high frequency low amplitude potential (HFLA), and root mean square (RMS) voltage in the terminal 40 ms of SAECG were determined. Results : In the preoperative period, group1 showed significant increase in QRS (P=0.011) compared to those of the other 2 groups. In the postoperative period, group3 showed significant increase in the QTc interval (P=0.004) compared to those in the other 2 groups. SAECG parameters showed no significant differences among the groups in the pre- or postoperative period. Of the 52 patients, 12 (23%) in the preoperative period and 21 (40%) in the postoperative period had at least 1 SAECG abnormality. The prevalence of SAECG abnormalities was significantly higher in the postoperative group 2 and group 3 (preoperative: 20% versus postoperative: 28%, P<0.001, preoperative: 14% versus postoperative: 64%, P<0.001, respectively). Conclusion : Abnormal SAECG patterns may be attributed to postoperative scars, OHS itself, and/or ventricular overload.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.1
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• pp.97-104
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• 2016

In Korea, the number of crash accident victims per 100,000 population is three times higher than the average of OECD. In particular, 60% of it occurs on the community road. Thus, this study intends to analyze the causes of such accidents through a pedestrian and vehicle traffic survey. The purpose is to establish practical safety enhancement measures for community roads. In recent years, lots of changes have occurred in the pedestrian environment. A traffic survey shows that 65% of pedestrians walk on the right and 17% of people use smart-phones while walking. An eye camera experiment shows that the operation load of drivers on the community roads is more than 4 times higher than those in urban roads. According to a speed survey, 62% of vehicles drive at 30km/h or above. The characteristics of accidents on community roads are as follows. First, the ratio of accidents on the edge of the road is 2.3 times as high as those on other roads. Second, when people walk on the right, the ratio of accidents is 2.5 times as high as that of walking on the left. Third, it becomes more dangerous when people cross the road from the right to the left. The majority of accidents is caused by unsafe driving (84.4%). When a vehicle makes a left turn, the likelihood of accidents is 2.3 times as high as those caused by a right turn. The ratio of accidents caused by vehicles going backwards is 14% among all accidents. In community roads, the focus of drivers should be at least 4 times higher than those on urban roads. Thus, walking in the opposite direction of vehicles and careless behaviors are highly likely lead to accidents.

• Journal of Chest Surgery
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• v.39 no.12 s.269
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• pp.891-899
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• 2006

Background: This study is to evaluate the safety of ATS valve by examining the clinical results of ten-years experience. Material and Method: From July 1995 to March 2005, we reviewed 305 patients with ATS valve implantation. Mean age was $49.8{\pm}11.7$ years and 140(45.6%) males were included. Etiologies were rheumatic diseases in 207 cases(67.4%), degenerative changes in 57 cases(18.6%), valve dysfunction in 23 cases(7.5%) and infective endocarditis in 14 cases(4.6%). AVR was performed in 72 patients(23.5%), MVR in 156 patients (50.8%), DVR(AVR+MVR) in 63 patients(20.5%) and TVR in 16 patients(5.2%). Result: There were 9 operative mortalities(2.9%). Follow up period was $56.5{\pm}34.0(0{\sim}115)$ months and 96.4% patients were followed up with 9 late deaths. Five and ten years survival rates were $94.9{\pm}1.3%,\;91.2{\pm}2.3%$ using Kaplan-Meier's methods. Valve related event free survival rates in 5 and 10 years were $90.8{\pm}2.0%$ and $86.9{\pm}3.2%$. There were 16 anticoagulation-related hemorrhages, 6 thromboembolisms, 3 prosthetic valve endocarditis and 1 paravalvular leakage. NYHA class improved after operation(p<0.05). Postoperative echocardiography showed significant decrease in LA size, LVEDD and IVESD(p<0.01). Patients with 19 and 21 mm valve showed significantly higher transvalvular pressure gradient in aortic position(p<0.001, p<0.001). Conclusion: ATS valve showed good hemodynamic results with few valve related complications and thus can be used with acceptable risk.

• Journal of Chest Surgery
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• v.42 no.1
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• pp.46-52
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• 2009

Background: Vascular injuries to the extremities are potentially devastating and they can lead to limb loss and mortality if they are not appropriately managed. The vascular trauma caused by traffic and industrial accidents has recently increased according to the developing industry and transport system in Korea. Early recognition and treatment of these injuries are mandatory to achieve satisfactory outcomes. Material and Method: We retrospective reviewed 43 patients with vascular injuries that were due to blunt and penetrating trauma and they underwent emergency operations from January of 1998 to December of 2006. Result: There were 38 men and 5 women patients with a mean age of $42.0{\pm}16.8$ years (range: 17~77). The cause of vascular injuries were 28 traffic accidents (65%), 6 industrial accidents (14%), 6 glass injuries (14%) and 3 knife injuries (7%). The average time from admission to the operating room was $319.0{\pm}482.2$ minutes (range: 27~2,400 minutes). The average time from admission to discharge was $53.1{\pm}56.0$ days (range: 2~265 days). The anatomic injuries included the femoral artery in 16 cases (37%), the popliteal artery in 8 cases (19%), the brachial artery in 8 cases (19%), and the subclavian and axillary arteries in 7 cases (16%). The associated injuries were 23 bone fractures (53%), 18 muscle injuries (42%) 5 nerve injuries (12%) and 11 vein injuries (26%). The operation methods were 20 end to end anastomoses (46%), 16 interposition grafts (36%), 2 repairs with using patches (5%) and 5 others (12%). The number of amputations and cases of mortality were 3 cases (7%) and 4 cases (9%), respectively. Conclusion: Minimizing ischemia is an important factor for maximizing salvage of extremities. Prompt diagnosis and treatment can reduce the amputation and mortality rates.