• Journal of Chest Surgery
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• v.27 no.7
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• pp.571-575
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• 1994

The hemodynamic effects of thyroid hormone are well established, and this hormone affects myocardial contractility, heart rate, and myocardial oxygen consumption. But the role of cardiopulmonary bypass on the thyroid function is not yet fully understood. We have studied twelve patients [male and female patients were equal in number] who were performed open heart surgery under cardiopulmonary bypass. The results are followed. 1] The serum level of T3 began to fall after cardiopulmonary bypass and sustained significantly till 24 hours after operation[p<0.05] 2] The concentrations of T4, Free T4, and TSH were slightly decreased after cardiopulmonary bypass but was maintained within normal range. 3] This above findings are similar to the "sick sinus syndrome" that is seen in severely ill patient. 4] We can propose that T3 would be effective in postoperative low cardiac output syndrome. syndrome.

• Journal of Chest Surgery
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• v.52 no.3
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• pp.155-161
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• 2019

Background: Coronary artery bypass grafting (CABG) is being offered increasingly frequently to octogenarians. However, old age is known to be an independent risk factor in CABG. The aim of this study was to compare the outcomes of off-pump coronary artery bypass (OPCAB) between octogenarians and septuagenarians. Methods: We retrospectively reviewed the data of 1,289 consecutive patients aged ${\geq}70years$ who underwent OPCAB at a single institution between 2001 and 2016. We compared the outcomes of 115 octogenarians and 1,174 septuagenarians. Using propensity score matching, based on preoperative clinical characteristics, 114 octogenarians were matched with 338 septuagenarians. Results: Propensity score analysis revealed that the incidence of acute kidney injury (14.9% vs. 7.9%, p=0.028) and respiratory complications (8.8% vs. 4.2%, p=0.040) was significantly higher in octogenarians. The early mortality rate (2.6% vs. 1.0%, p=0.240) and 1-year survival rate (89.5% vs. 94.4%, p=0.097) were not statistically significant between the groups. However, the 5-year survival rate (67.3% vs. 79.9%, p<0.001) was significantly lower in octogenarians. Previous myocardial infarction and a left ventricular ejection fraction ${\leq}35%$ were associated with a poor 1-year survival rate. Conclusion: Early and 1-year outcomes of OPCAB in octogenarians were tolerable when compared with those in septuagenarians. OPCAB could be a suitable option for octogenarians.

• Journal of Environmental Science International
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• v.12 no.12
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• pp.1235-1243
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• 2003

Under controlled conditions in an environmental chamber, 24 experiments were performed to compare the ability of a Variable-Air-Volume/Bypass Filtration System(VAV/BPFS) to remove indoor pollutants and to conserve energy with the ability of conventional Variable Air Volume(VAV) system. The specific conclusions of this paper were; first, the VAV/BPFS was more efficient than the VAV system in removing particulate matter, TVOC, and target VOCs. The total effective removal rate of PM for the VAV/BPFS was two times as high as that of the VAV system. The total effective removal rate of TVOC for the VAV/BPFS was 20 percent higher than that of the VAV system. Also each target VOC concentration was reduced by using the VAV/BPFS. Second, clean air delivery rate was increased by using VAV/BPFS due to additional filtration rate. Otherwise, the VAV/BPFS decreased outdoor supply air rate above 25 percent relative to the rate of VAV system. Third, total energy consumption by the VAV/BPFS was lower than that of the VAV system during the period with indoor thermal load, occupied time. The energy saving of the VAV/BPFS ranged from 11 to 16 percent. The VAV/BPFS improves indoor air quality more efficiently than the VAV system, and it reduced energy consumption. Retrofitting the VAV system with the VAV/BPFS was easy The use of VAV/BPFS is, therefore, recommended far buildings with VAV system as well as for buildings at designing stage.

• Journal of Chest Surgery
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• v.50 no.5
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• pp.371-377
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• 2017

Background: Lesions in distal target arteries hinder surgical bypass procedures in patients with peripheral arterial occlusive disease. Methods: Between April 2012 and October 2015, 16 patients (18 limbs) with lifestyle-limiting claudication (n=12) or chronic critical limb ischemia (n=6) underwent femoral-above-knee (AK) polytetrafluoroethylene (PTFE) bypass grafts with a bridging stent graft placement between the distal target popliteal artery and the PTFE graft. Ring-supported PTFE grafts were used in all patients with no available vein for graft material. Follow-up evaluations assessed clinical symptoms, the ankle-brachial index, ultrasonographic imaging and/or computed tomography angiography, the primary patency rate, and complications. Results: All procedures were successful. The mean follow-up was 12.6 months (range, 11 to 14 months), and there were no major complications. The median baseline ankle-brachial index of 0.4 (range, 0.2 to 0.55) significantly increased to 0.8 (range, 0.5 to 1.0) at 12 months (p<0.01). The primary patency rate at 12 months was 83.3%. The presenting symptoms resolved within 2 weeks. Conclusion: In AK bypasses with a diffusely diseased distal target popliteal artery or when below-knee (BK) bypass surgery is impossible, this procedure could be clinically effective and safe when used as an alternative to femoral-BK bypass surgery.

• Journal of Korean Neurosurgical Society
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• v.50 no.3
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• pp.185-190
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• 2011

Objective : To investigate the efficacy of extracranial-intracranial (EC-IC) bypass surgery using a radial artery interposition graft (RAIG) for surgical management of cerebrovascular diseases. Methods : The study involved a retrospective analysis of 13 patients who underwent EC-IC bypass surgery using RAIG at a single neurosurgical institute between 2003 and 2009. The diseases comprised intracranial aneurysm (n=10), carotid artery occlusive disease (n=2), and delayed stenosis in the donor superficial temporal artery (STA) following previous STA-middle cerebral artery bypass surgery (n=1). Patients were followed clinically and radiographically. Results : Bypass surgery was successful in all patients. At a mean follow-up of 53.4 months, the short-term patency rate was 100%, and the long-term rate was 92.3%. Twelve patients had an excellent clinical outcome of Glasgow Outcome Scale (GOS) 5, and one case had GOS 3. Procedure-related complications were a temporary dysthesia on the graft harvest hand (n=1) and a hematoma at the graft harvest site (n=1), and these were treated successfully with no permanent sequelae. In one case, spasm occurred which was relieved with the introduction of mechanical dilators. Conclusion : EC-IC bypass using a RAIG appears to be an effective treatment for a variety of cerebrovascular diseases requiring proximal occlusion or trapping of the parent artery.

• International Journal of Highway Engineering
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• v.12 no.4
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• pp.29-37
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• 2010

This study deals with the Right-Turn Bypass Lane in Roundabout. The purpose of the study is to comparatively analysis the effectiveness questions on the installation of right-turn bypass lane in roundabout. In pursuing the above, this study analyzed after and before of the right turn bypass lane plan by VISSIM software. The right turn bypass lane is formed by control type of yield and control type of joint were compared and analyzed the effects of the operation. The main results analyzed are as follows. First, after Right-Turn Bypass Lane is Installed, the traffic volume rate of the right-turn increasing by average delay time per vehicle is on the gradual decrease, maximum average about 28% with the fact that decreases. Second, control type of yield and control type of joint are both average delay time per vehicle decreasing by the traffic volume rate of the right-turn is on the gradual increase. Control type of joint was analyzed with the fact that has the maximum average about 18% delay decrement efficiency.

• Journal of Chest Surgery
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• v.32 no.6
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• pp.495-503
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• 1999

Background: We tested the technical feasibility of fetal cardiac bypass and collected baseline data on the fetal hemodynamics and placental functions related to the cardiopulmonary bypass in the fetal lamb model. Material and Method: Eleven fetuses at 120 to 150 days of gestation were subjected to bypass via trans-sternal approach with a 12 G pulmonary arterial cannula and 14 to 18 F venous cannula for 30 minutes. All ewes received general anesthesia with ketamine. In all the fetuses, no anesthetic agents were used except muscle relaxant. Eight served as a group in which placenta was excluded from the extracorporeal circulation by clamping the umbilical cord during the bypass(the oxygenator group) and in the remaining three, the placenta worked as the only source of oxygen supply(the placenta group). Observations were made every 10 minute during a 30-minute bypass and 30-minute post bypass period. No prostaglandin inhibitors were used both in ewes and in fetuses. Result: Weights of the fetuses ranged from 1.9 to 5.2 kg. In the oxygenator group, means of arterial pressure, PaO2, atrial pressure, heart rate, and bypass flow rate ranged 69.8 to 82.6 mmHg, 201.7 to 220.9 mmHg, 4.1 to 4.3 mmHg, 169 to 182/min, and 140.3 to 164.0 ml/kg/min, respectively during bypass, but rapid deterioration of the fetal cardiac functions and the placental gas exchange was observed after the cessation of bypass. In the placenta group, means of arterial pressure decreased from 44.7 to 14.4 mmHg and means of PaCO2 increased from 61.9 to 129.6 mmHg during bypass. Flow rate was suboptimal(74.3 to 97.0 ml/kg/min) during bypass. All hearts fibrillated immediately after the discontinuation of bypass. Conclusion: In this study, the technical feasibility of fetal cardiopulmonary bypass was confirmed in the fetal lamb model. However, further studies with modifications of the bypass including an addition of prostaglandin inhibitor, an application of the total spinal anesthesia on the fetus, a creation of more concise bypass circuit, and a use of active pump are mandatory to improve the outcome.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1265-1268
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• 2009

In this paper, the effect of a flow barrier and bypass on the cooling performance for a straight fin heat sink is presented. Both side directions and upward direction of bypass are controlled using various ducts which have different width and heights. In addition, a flow barrier is used to control flow toward heat sink. Through experiments, the distance from leading edge of a heat sink to a flow barrier is varied for various bypasses under fixed volume flow rate condition. This study shows possibility to improve cooling performance when bypass and a flow barrier exist.

• Journal of Chest Surgery
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• v.47 no.3
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• pp.225-232
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• 2014

Background: Redo coronary artery bypass grafting (CABG) is still associated with increased morbidity and mortality as compared to the first-time operation. Further, the application of the off-pump technique to redo CABG is limited due to technical difficulties. The aim of this retrospective study was to analyze early and midterm results after redo CABG and compare the outcome of redo on-pump and off-pump CABG. Methods: From June 1996 to October 2011, elective redo CABG was performed in 32 patients. Mean age was 64.8 years (on pump 64.3 years vs. off pump 65.5 years; p=0.658), and 21 patients were male. Among these patients, 14 (43.8%) underwent on-pump CABG, and 18 (56.2%) underwent off-pump CABG. Results: Internal thoracic artery was used in 22 patients (68.8%), and total arterial revascularization was achieved in 17 patients (53.1%). The average number of distal anastomoses was 2.13, and the rate of incomplete revascularization was 43.8%. The rate of total arterial revascularization was higher in the off-pump group (14.3% vs. 83.3%, p<0.001), and the use of saphenous vein graft was more in the on-pump group (78.6% vs. 16.7%, p<0.001). Overall hospital mortality was 3.1% (n=1) and was comparable in both groups (on pump 7.1% vs. off pump 0%; p=0.249). Postoperative complications occurred in 9 patients (64.2%), and the rate of complications was high in the on-pump group without statistical significance (64.2% vs. 33.3%, p=0.082). The mean follow-up duration was 5.4 years, and overall survival at 10 years was $86.0%{\pm}10.5%$. There was no significant difference in the 10-year survival rate between the two groups (79.6% vs. 100%, p=0.225). Conclusion: Redo CABG can be safely performed with acceptable mortality. Redo off-pump coronary artery bypass is feasible with low mortality and morbidity, comparable target vessel bypass grafting, and long-term survival. The off-pump technique might be considered a safe option for redo CABG in high-risk patients.

• Journal of Chest Surgery
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• v.33 no.2
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• pp.167-172
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• 2000

Background: As the internal mammary artery is far superior to the vein in the patency rate recently there has been a tendency to use the arterial graft as much as possible in coronary artery bypass grafts with the expectation of better the short- and long-term patency rate. Material and Method: We sequentially grafted the diagonal and the left anterior descending artery significantly influencing the cardiac function with the internal mammary artery. There were 32 cases of sequential grafts from July 1993 to December 1998: 21 men and 11 women. The age range was from 43 to 69 years with a mean age of 56.64$\pm$6.41 years. There were 22 unstable angina 7 stable angina and 3 acute myocardial infarction. 8 cases of them were accompanied by stenosis of the left main coronary artery. The grafts for coronary artery bypass surgery included the great saphenous vein at 60 the right gastroepiploci artery at 5 and the left internal mammary artery at 64 coronary arteries. Result: One patient died from sepsis and multiorgan failure. Complications included wound infections in two cases and gastrointestinal bleeding in one patient. All patients showed decrease or disappearance of angina after operation. The postoperative coronary angiogram performed in 9 patients showed neither occlusion nor stenosis of the grafts. Conclusion: This study suggests that sequential anastomosis of the internal mammary artery to the diagonal and the left anterior descending artery may result in excellent short-term patency diagonal and the left anterior descending artery may result in excellent short-term patency rate and be useful for the coronary artery bypass graft using only arterial grafts