• Journal of Chest Surgery
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• v.33 no.5
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• pp.407-418
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• 2000

Background: With open heart surgery(OHS), it has been recognized that many postoperative complications and postperfusion syndrome are associated with the activations of complements and leulocytes. Recently, some investigators also demonstrated that interlukin-6(IL-6) linked highly with postperfusion syndrome. The puropose of this study was to investigate the sequential changes of the IL-6 and to clarify each IL-6 relationship to the complements(C3, C4) and inflammatory response following cardiopulmonary bypass(CPB). Material and Method: To determine serum levels of IL-6, complements, leukocytes, and biochemistric markers of liver and renal function, blood samples were taken from th radial artery in 30 adult patients undergoing OHS with CPB. Result: Serum IL-6 levels incrased significantly at 10 minutes after CPB-on(CPB-10) in comparison with the control levels and reached the peak at CPB-off(p<0.05). Serum complement levels declined rapidly at CPB-10 and remained at the lower levels during CPB(p<0.01). Sequential changes of IL-6 levels had positive correlations with the changes of total leukocytes and neutrophil fractions(p<0.05), but had negative correlations with lymphocyte fractions(p<0.05). Changes of C3 related postively to monocyte fractions(p<0.05). Postoperative levels of total protein and albumin, decreased significantly in comparison with the control levels(p<0.01), while the postoperative levels of AST(aspartate transaminase) and bilirubin increased (p<0.01). At CPB-off, IL-6 levels had negative correlations with total protein and albumin levels(r=-0.60, -0.47 respectively, p<0.05), whereas C3 levels had positive correlations with albumin levels(r=0.40, p<0.05). IL-6 levels, as well as neutrophil fractions, had positive correlations with aortic clamp time(ACT) and total bypass time(TBT) (IL-6; r=0.82, 0.79 respectively, neutrophil fractions; r=0.50, 0.56 respectively, p<0.05), wheres lymphocyte frations and albumin levels had negative correlations whith ACT and TBT(lymphocyte fractions; r=-0.52, -0.58 respectively, albumin; r=-0.58, -0.55 respectively, p<0.05). Conclusion: These data showed that elevated production of serum IL-6 during CPB may play a pivotal role in systemic inflammatory responses and prologed CPB period may be assosiated with more sever postperfusion syndromes.

• Journal of Chest Surgery
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• v.41 no.4
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• pp.492-495
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• 2008

A functional single lung caused by lung diseases or pneumonectomy can result in anatomic and physiologic changes that may interfere with the conduct of subsequent coronary artery bypass surgery. Since. this type of case is extremely rare, there has not been any report on this in Korea. A 71-year-old female with a history of a destroyed left lung from pulmonary tuberculosis 13 years ago was admitted for evaluation of her increasing chest pain that she'd experienced for 2 weeks. Since coronary angiographies demonstrated 80% stenosis of the left main os, $90{\sim}95%$ stenosis of the p-LAD, 90% stenosis of the m-LCx and 90% stenosis of the RCA, coronary artery bypass surgery (CABG) was planned. Off-pump CABG with vein grafts through a median sternotomy was performed and the patient recovered the same as other CABG patients without complications.

• Journal of Chest Surgery
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• v.38 no.12 s.257
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• pp.828-834
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• 2005

Background: Off-pump coronary artery bypass grafting (OPCAB) has shown better outcome in chronic renal failure (CRF) patients by avoiding the effects of cardiopulmonary bypass. We evaluated renal function after OPCAB in CRF patients. Material and Method: 656 patients underwent OPCAB between January, 2001 and December, 2004. Data were collected in 26 CRF patients (Cr > 1.7 mg/dL). Preoperative/postoperative creatinine (Cr) levels, creatinine clearance and postoperative data were evaluated. We divided the patients into group 1 (Cr < 3 mg/dL) and group 2 (Cr $\geq$ 3 mg/dL). Result: Three patients started dialysis after surgery. Preoperative mean creatinine level (4.19$\pm$3.4 mg/dL) was elevated to 4.36$\pm$2.7 mg/dL at the third postoperative day and decreased below Preoperative level at the fifth postoperative day. In group 1 (mean Cr level=1.87$\pm$0.25 mg/dL), Cr level reached its peak level of 2.19$\pm$0.52 mg/dL at the fourth postoperative day (p=0.017), with subsequent decrease. Patients without pre- or postoperative dialysis (n=15) showed peak Cr elevation on postoperative day four (p=0.017) and subsequent decrease (p=0.01). Postoperative creatinine clearance showed reverse correlation with creatinine level. Conclusion: Creatinine level was elevated at third/fourth postoperative day, but decreased 5 days after surgery. Thus, if urgent dialysis is not indicated, postoperative renal replacement therapy in CRF patients may be better to be considered after four days observation.

• Journal of Chest Surgery
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• v.33 no.10
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• pp.785-791
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• 2000

Left ventricular dysfuction is common in immediate postoperative periods after surgical correction of heart diseases with chronic left ventricular volume overload. We speculated postoperative changes of left ventricular volume and unction in patients with patent ductus osus(PDA) who had underwent surgical repair at ages older than 16 years. Factors influencing postoperative left ventricular volume and function were also analyzed. Material and Method: From August 1989 to August 1999 thirty-siz adult patients with PDA 28 females and 8 males. were enrolled in this study. Their age ranged from 16 years to 57 years(mean :32 years). Types of surgical repair were division with primary closure in 22, division with patch closure in 6, internal obliteration using cardiopulmonary bypass in 4 and ligation in 4. Aortic clamping was combined during surgical repair in 22(61%) and cardiopulmonary bypass was used in 8(22%) Two-dimensional echocardiography studies were performed in 34(94%) preoperatively and in 25(66%) immediate postoperatively to assess postoperative changes of left ventricular internal dimensions. left ventricular volume and ejection fraction. Duration of postoperative follow-up ranged from 1 month to 99 months (mean:22 months) and 10 patients underwent 16 echocardiographic evaluation during this period Result : Preoperative and postoperative left ventricular systolic dimensions(LVIDs) were 42$\pm$8.0mm and 42$\pm$8.3mm left ventricular diastolic dimensions(LVIDd) were 64$\pm$10.0mm and 56$\pm$7.4mm left ventricular end systolic volumes(LVESV) were 62$\pm$19cc (z=1.87$\pm$0.06) and 59$\pm$24cc(z=1.78$\pm$0.08) left ventricular end diastolic volumes(LVEDL) were 169$\pm$40cc(z-1.17$\pm$0.1) and 112$\pm$29cc(z=0.85$\pm$0.1) and ejection fractions(EF) were 66$\pm$6.7% and 48$\pm$12.6% respectively. There were statistically significant differences between preoperative and postoperative values in LVDIDd(p=0.001) LVEDV(p=0.001) and EF(p=0.0001) while no significant difference is LVIDs and LVESV. Postoperative depression of ejcection fraction was significantly related with z-score of preoperative LVESV and LVEDV by univariateanalysis while LVEDV only was significant risk factor for postoperative LV dysfunction by multiple regressioin analysis ($\Delta$LVEF=-13.3-4.62$\times$LVEDV(z), p=0.001) During the follow-up periods ejection fractions become normalized in all except one patients. Conclusion ; Left ventricular function is usually deteriorated after the surgical correction of PDA in adult age and preoperative LVEDV is a major determinant of postoperative LV function.

• Journal of Chest Surgery
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• v.31 no.1
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• pp.32-39
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• 1998

High-dose aprotinin(Hammersmith regimen) has been widely used for years to control postoperative bleeding and reduce blood consumption in cardiac surgery but had known to cause some side-effects and had disadvantage in cost-effectiveness. The prospective controlled study of 33 patients undergoing cardiopulmonary bypass was performed to evaluate the efficacy for reducing postoperative bleeding and unfavorable effects of low-dose aprotinin. The level of hemoglobin and platelet in the blood and the amount of postoperative bleeding were assessed preoperatively, and postoperatively for the study of hemostatic function. The level of BUN and serum creatinine in the blood, levels of urine creatinine, total protein, albumin, alpha-1-microglobulin and creatinine clearance were assessed before and after the operation for the study of renal function. The aprotinin group had a significant reduction in chest tube drainage; 243$\pm$ 123 ml versus 406$\pm$303 ml(P=0.037) during 6 hours immediate-postoperatively, 494$\pm$358 ml versus 869$\pm$570 ml(P=0.045) during 24 hours postoperatively. The ratio of alpha-1-microglobulin/creatinine and microalbumin/creatinine in the urine were slightly increased in the aprotinin group postoperatively in comparison with the control group but there were no statistically significant difference(55$\pm$23 versus 24$\pm$10 in the alpha-1-microglobulin/creatinine, 56$\pm$19 versus 38$\pm$25 in the microalbumin/creatinine at post- operative 3rd day). There were no significant difference between two groups in other parameters of renal function, too. This study showed that low-dose aprotinin is an effective means of reducing postoperative bleeding without inducing significant renal dysfunction.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.13 no.2
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• pp.160-170
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• 1988

This paper describes the outboard NIU(Network Interface Unit) using microprocessor and the hardware and software of concentrator for constructing star typed LAN(Local Area Network) based on token ring method. The NIU adapter can adapter up to four parallel and serial typed terminals. Because it has PAD function on input output data, any type of terminals can be adapted. Since the concentrator has logical switching circuit which enables data to bypass the faulted NIU adapter, this network prevents communication break. When user transmits and receives data, the concentrator constructs star typed LAN which connct both transmitting and receiving sides. A s result, this network eliminated ring latency time in other NIU exculding transmitting and receiving NIU. So the throughput of this LAN is increased. Because this LAN system consists of several modultes according to it's function, the expansion of function or the modification of method is easy.

• Journal of Chest Surgery
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• v.30 no.7
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• pp.677-685
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• 1997

Thromboelastography(TEG) is the unique measure that gives rapid information about the whole clotting process. Simplifying the diagnosis of coagulopathy during operations, TEG can provide an adequate therapy for postoperative bleeding. Remarkable improvement in hemostasis after cardiopulmonary bypass(CPB) has been achieved by the treatment with proteinase inhibitor aprotinin, but the hemostatic mechanism of aprotinin during CPB is still unclear. This study was designed to evaluate the effects of aprotinin on coagulation system during CPB by using TEG. Forty patients who underwent CPB were divided into two groups: aprotinin(2u 106 kallikrein inhibition units, as a single dose into the cardiopulmonary bypass priming solution) treatment group(male 14, female 8, mean age=50.Byears) and no aprotinin treatment(control) group(male 10, female 8, mean age=53.4 years). TEG, activated clotting time, prothrombin time, activated partial thromboplastin time, platelet counts, fibrinogen an (ibrinogen degradation product(FDP) concentrations were checked before and after CPB(30 minutes after neutralization of heparin effect by protamine sulfate). There was no significant difference in other conventional coagulation tests of two groups except postcardiopulmonary bypass FDP concentration in control group, which was significantly increased compared to that in aprotinin group(p<0.05). In TEG variables of both groups, clot formation time(K) and alpha $angle(\alpha^{\circ})$ were significantly increased and decreased, respectively, after CPB(p<0.05), but fibrinolytic index(LYS60) was not changed during CPB. In aprotinin group, reaction time(R) was decreased significantly after CPB(p<0.05) but maximum amplitude(MA) was not changed(p>0.05). On the contrary, R was not changed markedly but MA was decreased significantly in control group after CPB(p<0.05). This result shows that main change in coagulation system during CPB is not hyperfibrinolysis but cecrease in clot strength by platelet dys unction, and the main effect of aprotinin during cardiopulmonary bypass is the maintenance of clot strength to the pre-CPB level by the preservation of platelet function.

• Journal of Korean Neurosurgical Society
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• v.56 no.3
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• pp.188-193
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• 2014

Objective : Moyamoya disease (MMD) is a chronic cerebrovascular occlusive disease of unknown etiology. In addition, the neurocognitive impairment of adults with MMD is infrequently reported and, to date, has not been well described. We attempted to determine both the neurocognitive profile of adult moyamoya disease and whether a superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis can improve the neurocognitive impairment in exhibiting hemodynamic disturbance without stroke. Methods : From September 2010 through November 2012, 12 patients with angiographically diagnosed MMD underwent STA-MCA anastomosis for hemodynamic impairment. Patients with hypoperfusion and impaired cerebrovascular reserve (CVR) capacity but without evidence of ischemic stroke underwent a cognitive function test, the Seoul Neuropsychological Screening Battery (SNSB). Five patients agreed to undergo a follow-up SNSB test. Data from preoperative and postoperative neurocognitive function tests were compared and analyzed. Results : Five of 12 patients were enrolled. The median age was 45 years (range, 24-55 years). A comparison of preoperative to postoperative status of SNSB, memory domain, especially delayed recall showed significant improvement. Although most of the domains showed improvement after surgery, the results were not statistically significant. Conclusion : In our preliminary study, large proportions of adult patients with MMD demonstrate disruption of cognitive function. This suggests the possibility of chronic hypoperfusion as a primary cause of the neurocognitive impairment. When preoperative and postoperative status of cognitive function was compared, memory domain showed remarkable improvement. Although further study is needed, neurocognitive impairment may be an indication for earlier intervention with reperfusion procedures that can improve cognitive function.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.361-367
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• 2014

This paper is related to a new solar power conditioner for a built-in step-up chopper function. In the first step-up chopper proposed solar PV power conditioner for mutually connected in series with the input voltage of the bypass diodes are respectively connected to the positive terminal should install the mutual boosting chopper diode connected in series with the boost chopper switching element between the two power supply and at the same time the first and the second was connected to a second diode and a resonance inductor and a snubber capacitor in series with each other. And the common connection point between the bypass diode and the step-up chopper and the step-up chopper diode common connection point of the switching elements of the input voltage was set to the boost inductor for storing energy. In addition, between the step-up chopper and the step-up chopper diode and a switching element of a joint connection point of the first auxiliary diode and the second common connection point of the auxiliary diode was provided, the resonance capacitor. Between the step-up chopper and the step-up chopper diode and a switching element of a joint connection point and the common connection point of the resonance inductor snubber capacitor and connecting the third secondary diode, between two power supply lines is characterized by configuring the DC link capacitor bus lines in parallel. Therefore, it is possible to suppress the switching loss through, DC link bus lines, as well as there could seek miniaturization and weight reduction of the power conditioner itself by using a common capacitor of the non-polar non-polar electrolytic capacitor having a capacitor, the service life of the circuit can be extended and it is possible to greatly reduce the loss can be greatly improve the reliability of the product and the operation of the product itself.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.3
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• pp.305-314
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• 2001

A modified model is proposed for calculation of transitional boundary layer flows. In order to develop the eddy viscosity model for the problem, the flow is divided into three regions; namely, pre-transition region, transition region and fully turbulent region. The pre-transition eddy-viscosity is formulated by extending the mixing length concept. In the transition region, the eddy-viscosity model employs two length scales, i.e., pre-transition length scale and turbulent length scale pertaining to the regions upstream and the downstream, respectively, and a universal model of stream-wise intermittency variation is used as a function bridging the pre-transition region and the fully turbulent region. The proposed model is applied to calculate three benchmark cases of the transitional boundary layer flows with different free-stream turbulent intensity (1%∼6%) under zero-pressure gradient. It was found that the profiles of mean velocity and turbulent intensity, local maximum of velocity fluctuations, their locations as well as the stream-wise variation of integral properties such as skin friction, shape factor and maximum velocity fluctuations are very satisfactorily predicted throughout the flow regions.