• Journal of Chest Surgery
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• 제32권7호
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• pp.628-636
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• 1999

배경: 최근에 완전방실중격결손의 해부학적 구조에 대한 이해가 증가됨에 따라서 본원에서는 수술방법에 있 어서 여러 가지 변형을 시도하게 되었다. 대상 및 방법: 1997년 5월부터 1998년 7월까지 8명의 완전방실중 격결손 환자를 수술하였다. 남녀 각각 3명, 5명이었으며 나이는 2개월에서 28개월까지 분포하였고 평균 몸무 게는 6.0$\pm$2.2 Kg이었다. 심장의 해부학적 구조에 따라서 3명의 환아에서는 심실중격결손을 일차적으로 봉합 하여 수술을 단순화하였다(Group I). 좌심실유출로 협착의 가능성이 있는 2명의 경우에는 통상적인 방법대로 2개의 포편을 이용하였다(Group II). 그리고 불균형 완전방실중격결손의 경우에는 심실중격결손을 막는 포편 을 우심실에 치우쳐서 막고 심방중격을 새로 만들거나 좌측 방실판막의 부족한 판막부위를 자가 심낭막으로 메꾸어 주거나 좌측 방실판막이 parachute valve 인 경우에는 2개의 판막입구를 만들어 주었다(Group III). 결과: 모든 환자가 수술후 만족스러운 혈류역학을 보였으며 7명에서는 평균 3$\pm$1 일만에 인공호흡기 이탈이 가능하였으며 1명의 환자는 심장의 문제없이 폐질환으로 24일만에 인공호흡기를 이탈하였다. 수술후 합병증 으로 III군에서 판막성형을 시행한 좌측 판막이 찢어지면서 판막역류가 점진적으로 심해진 1명에서 2주만에 재수술을 하였다. 조기 및 만기사망은 없었으며 수술후 심장초음파검사에서 약간의 좌측 방실판막협착이 III 군에서 1명 있었으며(평균압력차 6.5 mmHg), 좌측 방실판막역류가 7명(87.5 %)의 환아에서 Grade I 이하였으 며, 우측 방실판막역류는 모든 환아에서 Grade I 이하였다. 결론: 완전방실중격결손의 수술시 해부학적인 구 조에 따라서 선택적으로 일부 환아에서는 심실중격결손을 일차적으로 봉합함으로써 수술을 단순화할 수 있 으며 우심실이 발달된 불균형 완전방실중격결손에서도 변형수술방법을 통하여 양심실성 교정을 하여 좋은 결과를 얻을 수 있었다.

• 한국농공학회논문집
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• 제60권2호
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• pp.103-110
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• 2018

Most of the intake facilities of small agricultural reservoirs are conduits and they are regarded as serious defects due to the structural weakness that penetrates the body of the dam, and countermeasures are needed. This study suggests the application method of siphon type water intake facility by hydraulic model test and physical scale model test of siphon type water intake facility which has high safety and easy maintenance. Experimental results show that sufficient flow rate can be secured for the purpose of intaking water according to the differential head between the reservoir and the discharge part, and the flow rate can be controlled by the valve. The negative pressure was -31.5 kPa, and vibration and noise did not occur during the operation of the siphon. The maximum flow velocity in the discharge outlet was 1.11 m/s which meets the criterion for irrigation canals. Therefore, scour risk would be very low. As a result of the inflow distribution experiment, even if the inflow part is separated by only about 0.8 m, the flow velocity is remarkably decreased, so that the clogging by debris would not appear. When the pump was operated only once for the first time and the inside of the siphon was filled with water, continuous operation was possible by only valve operation. The results of this study are expected to be used for the design guidelines of the water intake facilities and improve safety and maintenance convenience of agricultural reservoirs.

• Journal of Chest Surgery
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• 제25권11호
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• pp.1327-1336
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• 1992

Between Jan. 1986 and Aug. 1992. 72 patients underwent Rastelli procedure. There were 43 male and 29 female, aged 46 days to 16 years [mean age, 5.2 years] with 18 patients less than 2 years of age. All patients had complex defect, 27 pulmonary atresia with ventricular septal defect, 18 corrected transposition of great arteries with pulmonary atresia or punmonary stenosis, 10 truncus arteriosus, 10 double outlet right ventricle with pulmonary atresia or stenosis, 7 complete transposition of great artersia with pulmonary atresia or pulmonary stenosis. The types of extracardiac valved conduit used were prosthetic valve[n=47, 24 car-bomedics, 19 Ionescu-Shiley, 4 Bjork-shiley] and hand-made trileaflet valve using pericardium. [n=23, 20 bovine pericardium, Z autologous pericardium, 1 equine pericardium] The mean size of valved cinduit was 5.25mm larger in diameter than the size of main pulmonary artery. [normalized to the patient`s body surface area] There were 17 hospital death[24%] and 4 late deaths[5.6%]. Postoperative complication rate was 38.9%a, none of which was conduit-related. All patients were followed pos-toperatively for 1 to 73 months. [mean 25.8 months] During follow-up period, reoperation was done in 6 patients due to stenosis of valved conduit. Mean interval between intial repair and reoperation was 20.3 months. In our experience, li recently extracardaic valved conduits between right ventricle [or pulmonary ventricle] and pulmonary artery were inserted with increasing frequency in infants less than 2 year, but hospital mortality was decreased, 2] Risk of reoperation due to conduit stenosis is low, so that the effect of graft failure on overall survival is minimized. 3] Nevertheless, because any type of extracardaic valved conduit is not ideal in children, we recommended that Lecompte should be done if cardiac anatomy is permitted.

• International Journal of Automotive Technology
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• 제3권1호
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• pp.27-32
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• 2002

Semi-active suspension systems are greatly expected to be in the mainstream of future controlled suspensions fur passenger cars. In this study, a continuous variable damper for a passenger car suspension is developed. It is controlled actively and exhibits high performance with light weight, low cost, and low energy consumption. To get fast response of the damper, reverse damping mechanism is adapted, and to get small pressure change rate after blow-off, a pilot controlled proportional valve is designed and analyzed. The reverse continuous variable damper is designed as a HS-SH damper which offers good body control with reduced transferred input force from tire, compared with any other type of suspension system. The damper structure is designed, so that rebound and compression damping force can be tuned independently, of which variable valve is placed externally. The rate of pressure change with respect to the flow rate after blow-offbecomes smooth when the fixed orifice size increases. Damping forces are measured with the change of the solenoid current at the different piston velocities to confirm the maximum hysteresis of 20N, linearity, and variance of damping farce. The damping farce variance is wide and continuous, and is controlled by the spoof opening, of which scheme is usually adapted in proportional valves. The reverse continuous variable damper developed in this study is expected to be utilized in the semi-active suspension systems in passenger cars after its performance and simplicity of the design is confirmed through real car test.

• Journal of Chest Surgery
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• 제25권1호
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• pp.32-41
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• 1992

From August 1982 to December 1991, 58 consecutive infants with tetralogy of Fallot underwent primary repair. Age ranged from 22 days to twelve months [n=58, 8.7$\pm$2.7 months] and body weight from 3.1 to 13 kilograms [n=58, 7.8$\pm$1.7 kilograms]. Qne infant had absence of the pulmonary valve; one had Ebstein`s anomaly and one had supramitral ring. Thirty-two patients [56%] experienced anoxic spell. Preoperative pulmonary artery indices were measured in 38 cases, ranging 126-552mm2/M2BSA[n=38, 251$\pm$79mm2/M2BSA]. All infants required a right ventricular outflow tract patch; in 41, the patch extended across the pulmonary valve annulus, in 13 of them, monocusps were constructed. All had patch closure of ventricular septal defect. Two infants had REV operation for avoiding injury to the canal branch of the right coronary artery which cross the right ventricular out flow tract. Post repair PRV/LV were measured at operating room in 40 cases, which revealed mean value of 0.49$\pm$0.12 [range: 0.25-0.74]. The hospital mortality was 10.3% [6 patients], and causes of deaths were right heart failure due to sustained right ventricular hypertension[4] and right ventricular outflow tract obstruction, intractablesuraventricular tachyarrhythmia[1], hypoxia[1] due to residual right to left shunt across the atrial septal defect in patient associated with Ebstein`s anomaly. All infants were doing well at follow-up from 1 to 101 months[20.6 months /patient, 1, 072 patient-month] Serial postoperative echocardiograms revealed no residual ventricular septal defects and estimated RVOT gradients between 0 and 40 mmHg except 3 cases [50, 50, 60 mmHg]. There were no late deaths and late ventricular arrhythmias or congestive heart failure. Redo operations were done in 2 cases because of residual right ventricular outflow tract obstruction. This experience with infants with tetralogy of Fallot suggests that, if mortality is tolerable, eletive repair of tetralogy of Fallot could be reasonably undertaken during the first year of life, and even better results could be anticipated along with improvement of methods of myocardial protection and postoperative care.

• Journal of Chest Surgery
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• 제33권2호
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• pp.139-145
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• 2000

Background: The purpose of this study is to review the clinical course after the correction of noncomplicated ventricular septal defect and to analyze the morbidity and risk factors of postoperative complications and evaluate residual defect during the follow-up period. Material and Method: From September 1994 to June 1998 24 patients(median age 10 months) underwent surgery under the diagnosis of ventricular septal defect. We made a retrospective review of the clinical records including the operation notes critical care unit records echocardiography results and the follow-up records. Result: There was no early mortality nd late mortality. There was no postoperative complete conduction block. Respiratory complication was the most common complication. The body weight age type of ventricular septal defect associated anomalies and operative procedure were not related to the incidence of complications. residual ventricular septal defects aortic valve regurgitation and tricuspid valve regurgitation were insignificant in postoperative hemodynamics, Conclusions: Correction of the noncomplicated ventricular septal defect was done without mortality and complete heart block. Aggressive preoperative medical treatment and early surgical treatment may decrease postoperative complications. Postoperative residual shunt and tricuspid regurgitation were not problematic during the follow-up

• 한국임상수의학회지
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• 제36권2호
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• pp.102-105
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• 2019

Nitrotyrosine was found to be dependent on the severity of myxomatous mitral valve disease (MMVD). However, a correlation of serum nitrotyrosine concentration in dogs with MMVD and the progression of the disease has not been investigated. This study compared changes in serum nitrotyrosine concentration with the progression of MMVD. Nine client-owned dogs were recruited for the study. Dogs were classified by measuring the amount of regurgitation using echocardiography into mild, moderate, or severe MMVD groups. Serum nitrotyrosine concentration was measured by an enzyme-linked immunosorbent assay test. Serum nitrotyrosine concentration was significantly higher at 180 days than at 0 day (P < 0.05). However, serum nitrotyrosine concentration at 360 days was lower than that at 180 days (P < 0.05). Serum nitrotyrosine concentration at 540 days was lower than at 180 days (P < 0.05). There was no correlation between serum nitrotyrosine and left atrial to aortic root diameter ratio (LA/Ao ratio) (n = 33, $R^2=0.003$, P = 0.759). Also, there was no correlation between serum nitrotyrosine and vertebral heart score (VHS) (n = 33, $R^2=0.026$, P = 0.368) and left ventricular end-diastolic diameter, normalized for body weight by the formula (LVEDDN) (n = 33, $R^2=0.053$, P = 0.196). The results of the study suggest that the progression of MMVD is correlated with changes in serum nitrotyrosine concentration, which shows potential for use as a cardiac biomarker which can be used to analyze the progression of disease in MMVD.

• Clinical and Experimental Pediatrics
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• 제62권6호
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• pp.240-243
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• 2019

Purpose: Coronary arterial lesion assessment in children can be difficult, depending on the coronary dominance pattern. Although it is easier to determine coronary dominance with echocardiography in children than in adults, it is still difficult. This study aimed to examine the coronary dominance pattern according to the objective coronary artery (CA) indices. Methods: The CA diameter, aortic valve annulus, and abdominal aorta of 69 children without any cardiovascular disease were measured with cross-sectional echocardiography at Chungnam National University Hospital. To evaluate the coronary dominance pattern, echocardiography was primarily used; additionally, coronary computed tomographic angiography or coronary angiography (CAG). Coronary dominance was determined according to the status of the CA that gives rise to the posterior descending artery. Results: The mean age was $4.02{\pm}2.78years$, and the mean body surface area (BSA) was $0.70{\pm}0.22m^2$. Right dominance was present in 78% and left in 22% of the subjects. In those with left dominance, the CA to aortic valve annulus diameter ratio was $0.125{\pm}0.021$ in the right coronary artery (RCA) and $0.255{\pm}0.032$ in the left coronary artery (LCA). In those with right dominance, the corresponding ratio was $0.168{\pm}0.028$ in the RCA and $0.216{\pm}0.030$ in the LCA (P<0.05). Significant differences were also found in the diametric ratios of the CA to BSA and abdominal aorta (P<0.05). Conclusion: The CA indices showed significant difference according to the coronary dominance pattern in early childhood. It is possible to indirectly determine the coronary dominance pattern with the CA indices in children using echocardiography. The accuracy of coronary artery lesion diagnosis can be improved by taking coronary dominance into account.

• 한국화재소방학회논문지
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• 제33권1호
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• pp.45-49
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• 2019

본 연구는 옥외저장탱크에서 발생한 화재의 근본적인 원인분석을 통해 저장탱크의 안전을 유지할 목적으로 수행되었다. 옥외저장탱크는 위험물을 장기간 저장하기 위한 고정장치로 탱크본체 및 부속장치로 구성되며, 부속장치는 벤트 시스템, 브레더 밸브, 화염방지기 등으로 구성된다. 화염방지기는 옥외저장탱크의 화재 폭발을 방지하기 위해 필요한 안전장치이다. 하지만 최근 발생한 옥외저장탱크 화재를 계기로 기존에 설치되어 운용중인 옥외저장탱크에 안전성 확보 차원에서 화염방지기를 의무적으로 설치해야 하는지 국내 외 기준을 비교 분석하여 화염방지기 설치가 필요함을 제시하였고, 화염방지기의 성능을 검증할 수 있는 국내기준이 부족하므로 외국 기준을 참고하여 보완할 필요성이 있다.

• Journal of Chest Surgery
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• 제40권8호
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• pp.536-545
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• 2007

배경: 소아 환자에서의 승모판폐쇄부전은 성인에 비해 상대적으로 드물고 다양한 형태의 병변을 보인다. 또한 수술 기법도 덜 정형화되어 있으며 그 결과에 대한보고는 드물다. 본 연구는 이러한 다양한 원인에 의한 승모판페쇄부전이 있었던 소아 환자에 대해 시행된 승모판성형술의 결과를 후향적으로 분석하고자 하였다. 대상 및 방법: 1993년 12월부터 2006년 8월까지 승모판폐쇄부전으로 수술 받은 18세 이하의 환자 35명을 대상으로 하였다. 수술 당시 평균 연령은 $5.3{\pm}5.3$세였고 평균 체중은 $20.0{\pm}16.3kg$이었다. 술 전 승모판폐쇄부전의 정도는 Grade II가 9예, III, IV가 각각 16예, 10예였다. 18예에서 심장 기형을 동반하고 있었으며 심실중격결손이 9예로 가장 많았고, 주관상동맥-폐동맥 이상 연결증, 좌측 주관상동맥기시부 폐쇄 등도 각각 2예, 1예 있었다. 승모판의 병리적 소견은 판막엽의 탈출증이 17예로 가장 많았고, 판막에 열이 있는 경우가 7예, 짧은 건삭을 보인 경우가 6예, 판막륜의 확장을 보인 경우가 5예, 허혈성유두상근을 보인 경우가 2예, 유두상근형성부전이 1예 있었고, 심내막염에 의한 건삭파열이 1예 있었다. 승모판성형술은 이중입구성형술이 15예로 가장 많이 시행되었고, 봉합판막륜성형술 14예, 판막열 봉합술 7예, 유두상근 분리술 5예, 링을 이용한 판막륜 성형술 4예, 판막엽 절제술 4예, 신건삭 형성술 2예 각각 시행되었다. 술 후 평균 추적 관찰 기간은 $47.5{\pm}39.0$개월($2{\sim}138$개월)이었다. 결과: 수술 후 조기 사망은 없었다. 술 후 승모판폐쇄부전의 정도는 1명의 환자를 제외하고 모두 의미 있는 감소를 보였다. 8명(24.2%)이 재수술을 시행 받았고 이 중 5명은 승모판치환술을 받았다. 재수술의 원인으로는 승모판 협착이 3예, 잔류 승모판폐쇄부전이 5예였다. 승모판협착은 링을 이용하여 수술한 4명의 환자 중에서 2명이 발생하였고, 폐쇄부전은 이중입구성형술을 시행 받은 환자 14명중에서 4명에서 발생하였다. 재수술 후 조기 사망 1명, 만기 사망 1 명이 있었다. 환자들의 5년 생존율은 $93.3{\pm}4.6%$, 5년 재수술의 회피율은 $76.1{\pm}8.2%$, 5년 승모판치환술의 회피율은 $83.6{\pm}6.7%$였다. 통계학적으로 의미 있는 재수술의 위험인자는 발견할 수 없었다. 결론: 승모판폐쇄부전이 있는 소아 환자에서 시행된 승모판 성형술은 양호한 중단기 성적을 보였으나 비교적 높은 재수술의 가능성은 남아 있어 향후 재수술의 원인과 대책에 대한 좀더 깊이 있는 연구가 필요하다고 생각한다.