• 한국화재소방학회논문지
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• 제27권3호
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• pp.30-37
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• 2013

본 연구는 가연성탱크 화재발생시 하나의 포 비례혼합기에서 분기헤더를 거쳐 다수의 소화지역 분기방식 포 소화설비의 분기헤더에서 저장탱크 하단부 입상관 까지의 포수용액 배관단면적 감소에 따른 통과유량 감소로 혼합비가 허용범위를 벗어날 때 적정농도의 포수용액 방출에 효과적인 방법을 확보하는데 궁극적인 목적이 있다. 이를 위해 기설치 포 소화설비의 유량변동에 따른 혼합비 변동원인 분석 및 일정혼합비 보상방법을 찾아보고, 포 비례혼합기 벤츄리 폼챔버 오리피스 및 미터링 오리피스 교체실험을 통해 원액흡입배관 단면적을 확장시킬 수 있는 미터링 오리피스 교체실험이 포 소화설비 혼합비 개선에 가장 효과적인 방안임을 입증하였다.

• Journal of Chest Surgery
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• 제35권7호
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• pp.523-529
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• 2002

배경: 관상동맥 우회술은 수술경험이 축적됨에 따라 근래에 조기수술성적이 점차 향상됨이 보고되고 있다. 본 연구에서는 관상동맥 우회술을 시행 받은 환자들에서 후향적 분석을 통하여 최근의 수술성적을 알아보고자 하였다. 대상 및 방법: 1996년 1월부터 2001년 8월까지 한양대학병원에서 154명의 환자가 관상동맥 우회술을 시행받았다. 전체 환자를 1996년부터 1998년까지 시행 받은 47명(제1기)과 그 이후에 시행 받은 107명 (제2기)으로 나누어 입원 기록을 근거로 술전진단, 수술방법, 사망률과 합병증을 후향적으로 분석하였다. 결과: 성비는 제1기에 남자 35명, 여자 12명, 제2기에 남자 78명 여자 29명으로 비슷한 분포를 보였고 평균 연령은 제1기 $55.9{\pm}62$세에서 제2기 $61.0{\pm}8.0$세로 의미 있게 증가하였다(p<0.05). 평균 좌심실 구출률은 제1기에 $54.6{\pm}11.8$% 제2기에 $56.9{\pm}13.0$%였다. 수술 위험 인자의 분포 중 술전의 심근경색이 제1기에 13명 (27.7%), 제2기에 14명(13.1%)로 의미 있는 차이를 보였다(p<0.05). 수술은 전례에서 중등도 저체온의 체외순환 하에서 시행하였고, 심근 보호 방법으로는 제1기에는 심실세동 상태에서의 간헐적 대동맥 차단, 또는 결정질 냉심정지액이 주로 사용되었고 제2기에서는 냉혈 심정지액이 사용되었다. 체외순환시간은 제1기에서는 $149.2{\pm}48.7$분 제2기에서는 $113.1{\pm}30.6$분으로, 대동맥 차단시간은 제1기에서는 $81.3{\pm}26.5$분 제2기에서는 $72.2{\pm}23.9$분으로 각각 의미 있게 단축되었다(p<0.05). 내흉동맥의 사용율은 제1기에서는 42%(20/47), 제2기에서는 81%(87/107)로 증가하였으며 환자 1명당 문합수도 제1기 $2.5{\pm}0.6$개소에서 제2기 $3.0{\pm}1.1$개소로 의미 있게 증가 하였다(p<0.05). 대동맥내풍선 펌프는 제1기에 7명, 제2기에 17명에서 사용되었는데 술 전 사용율은 제1기에 28.6%(2/7) 제2기에 52.9%(9/17)로 증가하였고 좌심실 기능 부전(LVEF<40%), 또는 울혈성 심부전 소견이 있는 환자에서 광범위 하게 적용하였다. 수술 사망율은 제1기에 5명이 사망하여 10.6%(5/47)을 나타내었고 제2기에 1명이 사망하여 0.9%(1/107)로 의미 있게 감소하였다(p<0.05). 결론: 체외순환을 이용한 관상동맥 우회술은 근래에 더욱 안전하게 시행될 수 있으며 수술의 보편화와 수술 경험의 축적에 따른 체외순환 과대동맥 차단 시간의 단축, 심근 보호의 발달 그리고 좌심실 기능 부전이나 심부전이 있는 환자의 적절한 관리, 특히 대동맥내 풍선펌프의 광범위한 적용이 수술 사망률을 줄이는데 기여했을 것으로 사료된다.

• Journal of Chest Surgery
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• 제35권10호
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• pp.712-723
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• 2002

체외순환은 뇌 혈류의 변화를 유도하며 이러한 변화가 수술 후 직 간접적인 뇌 손상의 원인이 될 수도 있다. 최근 체외순환 중 뇌 혈류 변화는 동맥혈액의 이산화탄소 분압과 밀접한 관련이 있는 것으로 보고되고 있다. 본 연구는 체외순환을 이용한 심장수술시 뇌 대사에 대한 정상 탄산분압과 고 탄산분압의 임상적 영향을 비교 조사하기 위해 전향적으로 계획되었다. 대상 및 방법: 심장수술이 계획된 36명의 성인 환자들을 연구목적에 따라 무작위적으로 정상탄산분압군(Pa$CO_2$35~40 mmHg, n＝18) 혹은 고탄산분압군(Pa$CO_2$45~55 mmHg, n＝18)으로 나눈 뒤 중등도 저체온(비인두 온도 29~3$0^{\circ}C$)의 비박동성 체외순환을 실시하였다. 수술 중, 각 환자들의 중대뇌동맥 혈류속도(뇌혈류 속도), 뇌동정맥 산소함량 차, 뇌산소 추출률, 뇌산소 대사율, 뇌산소 운반율, 뇌산소운반/뇌산소대사 비율, 뇌정맥 산소 불포화도(내경 정맥구 혈액 산소 포화도$\leq$50%), 동맥혈액 및 내경정맥 혈액 가스분석 등을 평가하였고, 수술 후 신경학적 합병증(섬망증세) 발생 정도 역시 관찰하여 양 그룹간에 비교하였다. 결과 : 체외순환 동안 고탄산분압군이 정상탄산분압군에 비해 뇌혈류 속도(169.13 $\pm$ 8.32 vs 153.11 $\pm$8.98%), 뇌산소 운반율(1,911.17$\pm$250.14 vs 1,757.40$\pm$249.56), 뇌산소운반/뇌산소대사 비율(287.38$\pm$28.051 vs 246.77$\pm$25.84), 내경 정맥구 산소분압(41.66$\pm$9.19 vs 31.50$\pm$6.09 mmHg), 그리고 내경 정맥구 산소포화도(68.97$\pm$10.96 vs 58.12$\pm$12.11%) 등이 유의하게 더 높았으나 (p＝0.03), 뇌동정맥 산소함량차(3.9$\pm$0.3 vs 4.9$\pm$0.3 mL/dL), 뇌산소 추출률(0.3$\pm$0.03 vs 0.4$\pm$0.03), 뇌산소 대사율(5.8 $\pm$0.5 vs 6.8$\pm$0.6), 동맥혈 pH는 고탄산분압군이 더 낮았다(7.36$\pm$0.09 vs 7.46$\pm$0.07, p＝0.04). 체외순환 동안 뇌정맥혈 불포화를 보인 환자 수는 고탄산분압군이 정상탄산분압군 보다 유의하게 더 적었다(3명 vs 9명, p＝0.03). 수술 후 신경학적 합병증(섬망)의 지속시간 역시 고탄산분압군이 정상탄산분압군 보다 더팔았다(36시간 vs 60시간, p=0.009). 결론: 이상의 연구결과들은 심장수술 동안 고탄산분압 체외순환이 뇌대사 및 수술 후 신경학적 결과에 보다 유익한 효과를 제공해 줄 수 있음을 시사하고 있다.

• Journal of Chest Surgery
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• 제13권4호
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• pp.338-345
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• 1980

We have modified an isolated perfusion rat heart model of cardiopulmonary bypass, with which we are able to screen the effects of various cardioplegic solutions and hypothermia upon the ability of the heart to survivie during and recover from period of ischemic arrest. The modified experimental model was differed from the original as follow : a heat coil chamber of atrial and aortic reservoir provided temperature control, and the perfusate was gassed with each pure oxygen and pure carbon dioxide in 95:5 ratio. The Langendorff perfusion was initiated for a 10 minute period by introducing perfusate at $37^{\circ}C.$ into the aorta from the aortic reservoir located 100 cm above the heart. The isolated perfused working rat heart model was a left heart preparation in which oxygenated perfusion medium (at $37^{\circ}C.$) entered the cannulated left atrium at a pressure of 20 cm $H_{2}O$ and was passed to the ventricle, from which it was sponeously elected(no electrical pacing) via an aortic cannula, against a hydrostatic pressure of 100cm $H_{2}O$. during this working period various indices of cardiac functin were measured. The cardiac functions were stable for over 3 hour with perfusion of Krebs-Henseleit bicarbonate buffer solution containing only glucose (11.1 mM/L). The percentage of cardiac functins were maintained about 94% on heart rate, 80.6% on peak aortic pressure, 87.7% on coronary flow and 76.3% on aortic flow rate after 3 hour of working heart perfusion at a pressure of 20 cm $H_{2}O$. We believe this preparation to be a good biochemical model for the human heart which offers many advantages including economic, speed of preparation, reproducibility, and the ability to handle large numbers.

• Journal of Chest Surgery
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• 제24권11호
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• pp.1045-1057
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• 1991

Over the past four decades after World War II a great deal of data and clinical experiences have been accumulated relating to the diagnosis and surgical treatment of cardiovascular diseases in Korea. Clinical data after the first open heart surgery by Professor Yung Kyoon Lee on August 7, 1959 up to 1984 revealed the total number of cardiovascular surgery in Korea as 13,100 cases performed in 22 institutes with overall hospital mortality of 7.7%[Cardiovascular Surgery in Korea 1985], Publishing committee of the Korean Thoracic and Cardiovascular Surgical Society collected the data of cardiovascular surgical cases in Korea again in between 1985 and 1990 from 38 institutes out of total 42 institutes of open heart centers in Korea. The results are: 1. The survey reply ratio was 90.5%[38 out of 42 institutes]. 2. Of the total 30,061 cases of cardiovascular surgery reported from 38 institutes 1,402 cases were failed as hospital mortality of 4.7%[4.5% of the 21,761 operations for congenital, and 5.2% of the 8,300 operations for acquired heart diseases]. Out of the total congenital cases, 17,303 cases were acyanotic group with a operative mortality as 2.0%, and 4,458 cases were cyanotic group with a hospital mortality as 14.le The incidence of corrective operations for complex congenital cardiac anomalies were increasing recently with decreasing age group. 3. During the year in 1990, 38 institutes performed 5,427 cardiovascular surgery with a hospital mortality of 3.4%. 4. Of the total cumulative 6,458 cases for cardiac valve surgery more than 90% cases were put to prosthetic valve replacement with hospital mortality as 4.8%. And the incidence of re-Do valve surgery was increasing recently as 13.1% in 1990. 5. Coronary artery bypass graft was increasing recently with 7.9% of hospital mortality in total 440 cases. Intracardiac operation for intractable arrhythmia was started since 1987 as 49 cases in total. Experiences on VAD and ECMO were also reported sporadically in recent year. 6. Home made oxygenator[OXYREX] is now in clinical use, and under animal experiment for clinical trial in near future.

• Journal of Chest Surgery
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• 제12권1호
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• pp.33-42
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• 1979

The present study reports 41 cases of congenital and acquired heart diseases, who received open heart surgery under extracorporeal circulation [ECC] by Sarns Heart-Lung-Machine [HLM] at the Department of Thoracic and Cardiovascular Surgery, Hanyang University Hospital during the` period between July 1975 and February 1979. The priming of pump oxygenator was carried out by the hemodilution method using Hartman`s solution, whole blood, and fresh human plasma. The rate of hemodilution was in the average of 50.8 ml/kg. ECC was performed at the average perfusion flow rate of 85.0 ml/kg/min [2.43 L./ kg/2] and at moderate hypothermia. In the total cardiopulmonary bypass, arterial pressure ranged between 55 mmHg and 90 mmHg, but generally maintaining over 70 mmHg. Patient age ranged between 2 and 54 year old, in congenital heart diseases, between 2 and 28, in acquired heart diseases, between 17 and 54 Sex ratio of male to female was 20:21. The cases include a case of pulmonary valvular stenosis, 4 cases of atrial septal defect, 9 cases of ventricular septal defect, 9 cases of tetralogy of Fallot, 5 cases of pentalogy of Fallot, 3 cases of atypical multiple anomalies 7 cases of mitral stenosis or insufficiency, a case of myxoma in left atrium, and a case of ruptured aneurysm of Valsalva`s sinus. The surgical managements were 16 valvulotomy for pulmonary valvular stenosis, 2 Teflon patch graft closure and 5 simple suture closure of atrial septal defect, 16 Teflon patch graft closure and 5 simple suture closure of ventricular septal defect, 12 pericardial patch graft for infundibular stenosis of right ventricle, one anastomosis between left superior vena cava and right atrium, 2 open mitral commissurotomy, 5 mitral valve replacement using Starr-Edward`s ball valve, porcine xenograft by Hancock, by Carpentier-Edward, or Angell-Shiley, one removal of left atrial myxoma, and a repair of ruptured aneurysm of Valsalva`s sinus. Four [9.7%] out 41 cases expired postoperatively and the rest of 37 cases survived with satisfactory results. The causes of death were one coronary embolism in tetralogy of Fallot, 2 postoperative lower cardiac output in atypical multiple anomalies, and one right heart failure in large: ventricular septal defect with pulmonary hypertension.

• Journal of Chest Surgery
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• 제10권2호
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• pp.268-273
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• 1977

During the period from March, 1963, to November, 1977, forty-eight patients with secundum type atrial septal defects have undergone surgical repair using cardiopulmonary bypass with a pump oxygenator at the Seoul National University Hospital. Twenty-six [55 percent] of the patients were females and Twenty-two [45 percent] were males. The patients varied in age from 3 years to 51 years. We have divided secundum defects into three types. These are: 1] the high defect; 2] Ovale type defect; and 3] low defect including the defect in the area of the coronary sinus. An ovale type defect was present in forty-one cases [85 percent]. Partial anomalous pulmonary venous connections were present in two patients in the high defect group. All of the forty-eight patients had had right heart catheterization before operation. The pulmonary to systemic flow ratio [Qp/Qs] was determined in our 38 patients. The Qp/Qs was less than 1.5/1 in only five of the 38 patients. Among the 33 patients with moderate and severe left-to-right shunts [Qp/Qs 1.6-3.5/1], the systolic pulmonary artery pressures. ranged from 30 to 80 mm Hg. Large left-to-right shunts [Qp/Qs>3.6/1] were present in 13 patients. The postoperative complications occurred in 13 patients [27. 1 percent]. Postoperative wound infections were the most frequent complications being present in 6 patients [12.5%]. Forty-six of the patients with secundum atrial septal defects survived surgical repair of their defects. Thus the hospital mortality of surgery was 4.2 percent. The causes of death in the early postoperative period were: 1] low cardiac output syndrome related to severe pulmonary hypertension in one case; and 2] postoperative several bleeding in one case.

• Journal of Chest Surgery
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• 제51권1호
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• pp.15-21
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• 2018

Background: Prosthetic valve endocarditis (PVE) is a serious complication of cardiac valve replacement, and many patients with PVE require reoperation. The aim of this study was to review our institutional 20-year experience of surgical reoperative valve replacement in patients with PVE. Methods: A retrospective study was performed on 84 patients (mean age, $54.8{\pm}12.7years$; 51 males) who were diagnosed with PVE and underwent reoperative valve replacement from January 1995 to December 2016. Results: PVE was found in 1 valve in 61 cases (72.6%), and in 2 or more valves in 23 cases (27.4%). The median follow-up duration was 47.3 months (range, 0 to 250 months). Postoperative complications occurred in 39 patients (46.4%). Reinfection occurred in 6 cases, all within 1 year. The freedom from reinfection rate at 5 years was $91.0%{\pm}3.5%$. The overall survival rates at 5 and 10 years were $64.4%{\pm}5.8%$ and $54.3%{\pm}7.3%$, respectively. In stepwise multivariable Cox proportional hazard models, older age (hazard ratio [HR], 1.48; 95% confidence interval [CI], 1.05 to 2.10; p=0.027) and cardiopulmonary bypass (CPB) time (HR, 1.03; 95% CI, 1.00 to 1.01; p=0.033) emerged as independent risk factors for death. Conclusion: Older age and a longer CPB time were associated with an increased risk of overall mortality in PVE patients.

• 한국추진공학회지
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• 제19권5호
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• pp.52-61
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• 2015

본 연구에서는 가변 입구 안내익과 블리드 공기 스케줄에 따른 터보팬 엔진에서의 천이 성능특성을 수치적으로 분석하였다. 대상 엔진으로 저 바이패스비 혼합 흐름 터보팬 엔진을 선정하였다. 압축기 가변 입구 안내익에 따른 성능 변화를 고려하기 위해 평균 반경 해석법을 이용하여 압축기 성능성도를 도출하고 엔진 해석 프로그램에 입력하였다. 정상상태 조건에서 축류 압축기 서지마진 10%를 만족하도록 회전속도에 따른 가변 입구 안내익과 블리드 공기 스케줄을 각각 도출하였다. 도출된 스케줄을 이용하여 엔진 천이 성능해석을 수행하였다. 엔진 천이 성능해석 수행 결과 가변 입구 안내익을 사용하는 경우가 블리드 공기를 사용하는 경우보다 천이과정에서 높은 서지마진과 낮은 터빈 입구 온도를 보였다.

• Journal of Chest Surgery
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• 제28권2호
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• pp.136-142
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• 1995

A clinical study was performed on 69 cases of isolated PDA surgically treated at the Department of Thoracic and Cardiovascular surgery of Kyung-Hee University Hospital from Mar. 1986 to Feb. 1994. Retrospective clinical analysis of these patients were as follows: 1.23 males and 46 females ranged in age from 16 days to 49 years. [mean 8.69yrs.,sex ratio M:F=1:2 2. Chief complaints were frequent URI in 44%, dyspnea on exertion in 16%,palpitation in 8%, easy fatigability in 6%, and no subjective symptoms in 26%. 3. On auscultation, typical continuous machinery murmur heard in 84%, and systolic murmur in 16% on Lt 2nd or 3rd intercostal space. 4. Simple chest x- ray showed increased pulmonary vascularity in 67%, cardiomegaly in 61%,and within normal limit in 16%. 5. EKG findings were LVH in 42%, biventricular hypertrophy in 17%, RVH in 3%, and within normal limit in 38%. 6. Echocardiogram was performed from all patient, and direct visualization of ductus in 93% 7. Cardiac catheterization was performed in 39 patients. The mean value of the results were;Differance SaO2[MPA-RV =11.03$\pm$ 5.26%,Qp/Qs=2.44$\pm$1.35,systolic pulmonary arterial pressure=40.69 $\pm$ 17.69mmHg. 8. 66 patients were operated through the left posterolateral thoracoctomy ; closure of ductus by double ligation in 43 cases, triple ligation in 23 cases.3 patients were operated by simple closure under cardiopulmonary bypass. 9. There was no death associated with the operation. The operative complications were atelectasis in 8 cases, pneumonia in 4 cases recannalization in 2 cases, and hoarseness in one case. 10. Systemic diastolic pressure was increased 8.12$\pm$ 0.13mmHg, and pulse pressure was decreased about 9.52 $\pm$ 1.87mmHg.