• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.399-402
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• 2003

In this paper, the on line volt/var control algorithms of the food Load Tap Changer (LTC) transformer and Shunt Capacitor(SC) are proposed for distribution volt/var regulation. In the existing volt/var control of the distribution substation, the voltage of feeders and var of distribution systems is mainly controlled by the LTC transformer tap position and on/off status of the shunt capacitor. The LTC and shunt capacitor bank has discrete operation characteristics and therefore it is very difficult to control volt/var at the distribution networks within the satisfactory levels. Also there is limitation of the operation times of the LTC and shunt capacitor bank because it is affects on their functional lifetime. The proposed volt/var control algorithm determine an optimal tap position of LTC and on/off status of shunt capacitors at a distribution network with the multiple feeders. The mathematical equations of the proposed method are introduced. Simple case study was performed to verify the effectiveness of the proposed method.

• Archives of Craniofacial Surgery
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• v.18 no.3
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• pp.186-190
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• 2017

We report a case of free flap deterioration which may have been induced by pressure gradient resulting from cranial defect overlying a ventriculoperitoneal shunt (VP shunt). The patient, male and aged 78, had a VP shunt operation for progressive hydrocephalus. Afterwards, the scalp skin flap surrounding the VP shunt collapsed and showed signs of necrosis, exposing part of the shunt catheter. After covering the defect with a radial forearm free flap, the free flap site showed signs of gradual sinking while the vascularity of the flap remained unimpaired. An agreement was reached to remove the shunt device and observe the patient for any neurological symptoms, and after the shunt was removed and the previous cranial opening filled with fibrin glue by Neurosurgery, we debrided the deteriorated flap and provided coverage with 2 large opposing rotational flaps. During 2 months' outpatient follow-up no neurological symptoms appeared, and the new scalp flap displayed slight depression but remained intact. The patient has declined from any further follow-up since.

• Journal of Chest Surgery
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• v.38 no.4 s.249
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• pp.277-283
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• 2005

Arterial oxygen saturation $(SaO_2)$ instability frequently takes place after systemic-pulmonary shunt without shunt occlusion. We analyzed actual incidence and risk factors for $SaO_2$ instability after shunt operations, and possible mechanisms were speculated on. Material and Method: Ninety three patients, who underwent modified Blalock-Taussig shunt from January 1996 to December 2000, were enrolled in this study. Adequacy of shunt was verified in all patients, either by ensuing one ventricle or biventricular repair later on or by appropriate pulmonary artery growth on postoperative angiogram. Age, body weight, hemoglobin level at operation were 3 day to 36 years (median: 1.8 months), 2.5kg to 51kg (median: 4.1kg) and $10.7\~24.3$ gm/dL (median: 15.2 gm/dL) respectively. Preoperative diagnoses were functional single ventricle with pulmonary stenosis or atresia in 39, tetralogy of Fallot in 38 and pulmonary atresia with intact ventricular septum in 16. Pulmonary blood flow (PBF) was maintained pre-operatively by patent ductus or previous shunt in 64 and by forward flow through stenotic right ventricular outflow tract (RVOT) in 29. $SaO_2$ instability was defined as $SaO_2$ less than $50\%$ for more than 1 hour with neither anatomic obstruction of shunt nor respiratory problem. Result: 10 patients $(10.7\%)$ showed $SaO_2$ instability after shunt operation. After shunt occlusion was ruled out by echocardiogram, they received measures to lower pulmonary vascular resistance (PVR), which worked within a few hours in all patients. Risk factors for $SaO_2$ instability included older age at operation (p=0.039), lower preoperative $SaO_2$ (p=0.0001) and emergency operation (p=0.001). PBF through stenotic RVOT showed marginal statistical significance (p=0.065). Conclusion: $SaO_2$ instability occurs frequently after shunt operation, especially in patients with severe hypoxia pre-operatively or unstable clinical condition necessitating emergency operation. Temporary elevation of pulmonary vascular resistance is a possible mechanism in this specific clinical setting.

• Journal of Chest Surgery
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• v.15 no.2
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• pp.194-203
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• 1982

In this investigation we undertook to evaluate the utility of radionuclide cardiac angiography in the detection of cardiac shunts before and after surgical correction. Time-activity curves of ventricles and lungs were evaluated after bolus intravenous injection of 99mTc-human serum albumin in 512 preoperative patients and 551 post-operative patients. Omitting 31 cases of technical failure due to poor bolus, we detected shunts in 459 cases of 481 preoperative evaluations, so the detectability was 95.4%. The cases which couldn`t be detected by this method had small amount of shunt. Also the degree of shunt detected by radioisotope methods were well correlated with oxymetry method. [r=0.89, p<0.01 ] In postoperative evaluations, 18 out of 411 patients with left to right shunt and 10 out of 140 right to left shunt were found to have remnant shunts with radionuclide cardiac angiography. Of the 28 cases with failed operation, 2 were confirmed in reoperation, 2 by cardiac catheterization, 2 by two -dimensional echocardiography. All except one .f these patients had membranous ventricular septal defects and those with left to right shunts had moderate to severe pulmonary hypertension and shunt amount. Also those had larger septal defects than control group. We consider that radionuclide cardiac angiography is a simple and noninvasive method which can show the preoperative diagnosis and postoperative follow up of cardiac shunts.

• Journal of Chest Surgery
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• v.21 no.1
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• pp.10-16
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• 1988

Ten patients with tetralogy of Fallot were studied angiocardiographically before a modified Blalock-Taussig shunt and again 25*3.2 months after the previous shunt. All of ten patients had patent previous shunt at the time of follow up examination. Pre-and postoperative diameters of left and right pulmonary artery and descending aorta were measured and pulmonary artery index [the sum of the crossectional areas of the right and left pulmonary arteries standardized by the body surface area] was calculated. The ratio of mean diameter of left and right pulmonary arteries to the diameter of the descending aorta [LPA+RPA/2xDA] was increased postoperatively by 0.20*0.068 [p=0.020]. Mean PAI [pulmonary artery index] increased from 283.8*178.4 mm/m2 BSA to 345.8~144.5 mm/m2 BSA after shunt operation [p=0.019]. This results suggested that the modified Blalock-Taussig shunt was effective to help growth of the pulmonary arteries in most cases of the study populations but the ones with the PAI>233mm*/m* BSA appeared less benefited by Blalock Taussig shunt. Calculation of PAI could be an aid to making a decision whether to perform a one stage corrective surgical procedure or a palliative shunt procedure in the patient with small pulmonary arteries.

• Journal of Chest Surgery
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• v.16 no.1
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• pp.91-96
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• 1983

A study was carried out to observe the clinical progress and results after modified Blalock-Taussing shunts on II patients with cyanotic complex heart diseases unsuitable for corrective surgery. The operation was performed by interposing a vascular prosthesis [PTEE] between the left subclavian artery and the left pulmonary artery. Vascular prostheses larger than the diameter of left subclavian artery were selected. The results were as follows: 1. The postoperative courses in 10 patients were uneventful without any complications. One patient died of low cardiac output syndrome immediate postoperatively. 2. The average value of RBC count before operations was 751.2291.68 [xl00]/cubic mm. It was decreased to 588.11 90.45 [xl 0,000]/cubic mm. After the operation. 3. The average value of Hemoglobin before operations was 20.07 3.01 mg/dl. The value was decreased to 15.361.68mg/dl after the operation. 4. The value of Hematocrit before operations was 62.878.89%. The value was decreased to 49.6 5.84% 5. Patency after the shunt operations using PTFE was good for maximal 16 months follow-up period. 6. The physiological impairment like anoxic spells, degree of cyanosis and other clinical symptoms were markedly improved after the shunt operations. Although a longer follow-up seems to be necessary to assess the validity of these shunts, the early results were encouraging.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.184-186
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• 2003

As STATCOM is considered to be installed in bulk power system, various studios are conducted to establish strategies for system operation considering STATCOM. This paper describes control strategy for coordinating STATCOM with existing switched shunt in bulk power system.

• Clinical and Experimental Pediatrics
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• v.49 no.10
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• pp.1106-1110
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• 2006

Chylous ascites is a rare condition caused by various diseases and conditions that interfere with the abdominal or retroperitoneal lymphatics, and uncommonly it can manifest as a post-operative complication after abdominal, retroperitoneal or mediastinal surgery. Chylous ascites can be diagnosed by a high triglyceride content in ascites. The authors experienced a 5-year-old girl with congenital hepatic fibrosis who presented with chylous ascites after a splenorenal shunt operation, who was successfully managed by fasting and total parenteral nutrition, followed by a lipid-free diet with medium chain triglyceride supplementation. Here, the authors report this case of post-operative chylous ascites after a splenorenal shunt (Warren shunt) operation with a review of the pertinent literature.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.4
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• pp.1765-1773
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• 2013

The purpose of this study was to contribute to the medical treatment of subdural effusion through clinical sequence analysis of patients who experienced improvement of subdural drainage and had a second operation for subdural drainage or subduroperitoneal shunt. Sixteen cases of the whole patients who have been underwent subdural effusion and subdural drainage were analyzed during the period from 2006 July to 2012 June. The study gave us a result that all of patients, who was taking aspirin, have been under the second operation(p<0.001) and these group have had a subduraoperitoneal shunt(p=0.014)). According to the comparative analysis for the patients group that divided into two; one had subduroperitoneal shunt and the other had no subduroperitoneal shunt, the outcomes of this study were shown as follows. First, their median line deviation was serious in their brain CT. In addition, their subdural effusion increased or did not change with a headache, vomiting, fever and dyspnea. As a result of those symptoms. subduraoperitoneal shunt was carried out(p=0.006). The surgical method for patients who were taken asprin must be cautiously selected and the prevention of sudden disappearance of cerebrospinal fluid and excessive change of intracranial pressure is very important in operation craniectomy.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.9-11
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• 2003

In power system planing and operation, voltage and reactive power control are very important. The voltage deviation and system losses can be reduced through control of reactive power sources. In general, there are several different reactive power sources, we used UPFC and switched shunt capacitor to improve the voltage profile and to reduce system losses in this study. Since there are many switched shunt capacitors in power system, so it is necessary to coordinate these switched shunt capacitors. In this study, Genetic Algorithm(GA) is used to find optimal coordination of UPFC and switched shunt capacitors in a local area of power system. In case study, the effectiveness of the proposed method is demonstrated in KEPCO's power system. The simulation is performed by PSS/E.