• Journal of Chest Surgery
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• v.23 no.4
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• pp.731-735
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• 1990

Simultaneous and non simultaneous bilateral spontaneous pneumothorax patients[273] were reviewed retrospectively from April 1986 to March 1990 in the Dept. of Thoracic and Cardiovascular Surgery, Kyung Hee University Medical College. The incidence of bilateral spontaneous pneumothorax was 13.6%[37] and sexual distribution was male dominant [Male:33, Female:4]. The patients were classified into three major groups according to therapeutic methods: Group I [7]; who were treated with simultaneous bilateral operation for unilateral recurred spontaneous pneumothorax through median sternotomy. Mean age was 20.7 years[17 \ulcorner28] and follow up duration was 7.7 months [3 weeks \ulcorner2 years]. Group II [23];who were treated with staged lateral thoractomy, unilateral thoracotomy and non simultaneous contralateral closed thoracostomy, or simultaneous or non simultaneous bilateral closed thoracostomy. Mean age was 28.6 years [17 \ulcorner56] and follow up duration was 9.8 months[one week \ulcorner3.5 years]. Group III[10] ;who were treated with simultaneous bilateral operation for simultaneous or non simultaneous bilateral spontaneous pneumothorax through median sternotomy. Mean age was 21.4 years[17 \ulcorner28] and follow up duration was 12.8 months[2 weeks \ulcorner2.7 years]. Among the patients managed through median sternotomy simultaneously [Group I and III], there were visible blebs or bullous changed lesions mainly in the apicoposterior segment bilaterally in 15 patients[88.2%] Postoperative complications were 3 cases in Group II [wound infection:2 cases, temporary left wrist drop: one case] but none in Group I and III. Spontaneous pneumothorax recurred in 2 cases, one in Group II and another in Group III but none in Group I. 12 cases of 94 patients[12.8%o] who were treated with unilateral thoracotomy needed contralateral thoracotomy mean 14.9 months[7.5 \ulcorner 25 months] later. Mean age was 20.9 years [17 \ulcorner28]. In conclusion, simultaneous bilateral operation through median sternotomy should be considered in managements of spontaneous pneumothorax, especially in late teens and early twenties except young women for cosmetic reasons.

• Journal of Chest Surgery
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• v.32 no.10
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• pp.943-946
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• 1999

There was no significant difference in morbidity and mortality between those that received simultaneous operation for coronary artery disease and peripheral vascular disease versus those that received coronary artery bypass graft alone. Simultaneous operation is also cost effective. A 46 year-old patient with resting chest pain and intermittent claudication was diagnosed as unstable angina and Leriche's syndrome. We performed simultaneous revascularization for coronary artery stenosis with internal mammary artery and right gastroepiploic artery and a bifurcated vascular graft interposition between in the aorta, left common iliac and right femoral arteries for Leriche's syndrome. The postoperative coronary angiogram and aortogram revealed a good patency of the arterial conduits and vascular graft. He has been followed for 12 months without any problem.

• Journal of Chest Surgery
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• v.29 no.2
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• pp.227-230
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• 1996

Air space disorders are usually considered medical diseases, although some patients with air space disorders can benefit from surgical intervention. Recently we experienced two cases of bullous emphysema. One case is large bilateral apical bullae and the other is infected large bulls of RUL with bullous emphysema. The patient with large bilateral apical bullae underwent simultaneous operation via bilateral thoracotomy and other patient underwent simultaneous bilateral operation via median sternotomy. Postoperatively, the patient with large bilateral apical bullae showed subjective as well as objective improvement and other patient is resulted subjective improvement.

• Advances in pediatric surgery
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• v.14 no.1
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• pp.48-57
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• 2008

Prophylactic contralateral exploration in unilateral inguinal hernia repair is still controversial. The purpose of this study is to analyze the contralateral incidence of hernia and to verify the necessity of the simultaneous contralateral exploration. Infants and children operated on for inguinal hernia or hydrocele at the Department of Pediatric Surgery of Asan Medical Center from January 1996 to December 2005 were analyzed retrospectively. A total of 383 patients (9.8 %) out of 3,925 patients underwent a simultaneous bilateral operation. A total of 222 patients (6.2 %) out of 3,542 patients underwent a secondary metachronous contralateral operation after primary unilateral inguinal hernia or hydrocele repair. Because simultaneous bilateral operation cases included true bilateral inguinal hernia or hydrocele, and unilateral hernia and simultaneous contralateral exploration, bilateral incidence of inguinal hernia and hydrocele could be maximally considered as 15.4% (605 patients). Therefore, the prophylactic contralateral exploration in unilateral inguinal hernia or hydrocele should be determined carefully in considering history and physical examination of the patients, and postoperative complications.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1626-1632
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• 2007

Power Car PC1 and PC2 of Korean high speed train have a auxiliary block which consists of two PWM converter respectively. If a auxiliary block happens a critical failure, the other supplies power to full load of train. In this case, a stability of auxiliary block reduces by a increasing load. For increasing a stability of auxiliary block and train system, a auxiliary block consists of two group four PWM converter which operates simultaneously. If a group of a auxiliary block happens a critical failure, the other supplies power to load of a auxiliary block. This paper describes a method for simultaneous movement of auxiliary block which consists of two group four PWM converter.

• Journal of Chest Surgery
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• v.23 no.4
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• pp.720-730
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• 1990

The complicated pulmonary emphysema including “Giant bullae” and spontaneous pneumothorax often involve both lungs, and controversy exists concerning which is the more rational means of surgical treatment-bilateral simultaneous operation or two staged operation. We report three cases of the complicated bilateral bullous emphysema and two cases of bilateral spontaneous pneumothorax treated through median sternotomy. We performed the ligation of bullae, bullectomy, cystectomy, wedge resection, and left lower lobectomy through median sternotomy. No technical problems were encountered through this approach, which provided maximum benefit with one operation In conclusions, median sternotomy may be appropriate for resection of emphysematous bullae, specially in a severe COPD patient who may be poorly tolerated the superimposed loss of respiratory function due to incisional pain, because median sternotomy permit bilateral exploration, minimal impairment of pulmonary function, simultaneous restoration of pulmonary function, less incisional pain than routine lateral thoracotomy.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.3
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• pp.131-136
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• 2013

The present study has conducted cycle design and control technology of a water source VRF heat pump system. Previously, study of a simultaneous heating and cooling in an air source VRF heat pump system has been conducted. However, performance data and design methods for simultaneous heating and cooling in a water source VRF heat pump system are limited in the literature, due to various system parameters and operating conditions. In this study, the operating characteristics and performances of a simultaneous heating and cooling heat pump system are carried out, in simultaneous operation modes. Control logics of an EEV are developed for flow rate control to the outdoor unit, and are verified. When the control logics are applied, the simultaneous cooling and heating performances are sufficiently achieved, and system COPs are increased by up to 23.4%.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.6
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• pp.862-867
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• 1995

In this paper a method to perform Exclusive-OR operation between two tabular type Boolean expressions is presented. The proposed method allows to solve the switching equations and the simultaneous equations in a rather direct manner, compared with Unger's method.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.4
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• pp.311-317
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• 2004

In the present study, the cooling characteristics of the multi-air conditioner (A/C) using an inverter scroll compressor are experimentally investigated for the number of the indoor units and the operating conditions (2$0^{\circ}C$, 24$^{\circ}C$, 26$^{\circ}C$) under the cooling standard conditions by KS C 9306. In the case of the simultaneous operation for 3 indoor units, the cooling capacity, the mass flow rate and the input power have a decreasing trend and COP has an increasing trend, with decreasing the difference in the operating temperature of the indoor unit and the room temperature. In the case of the simultaneous operation for 2 indoor units, the COP of the indoor unit with large cooling capacity is high when the operating temperature is high, but the COP of the indoor unit with low cooling capacity is high when the operating temperature is low. In the case of the single operation for one unit, when the large cooling capacity of the indoor unit is less than 50％ the compressor operates at the minimum operation frequency region and the COP decreases.

• Journal of Chest Surgery
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• v.26 no.1
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• pp.54-58
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• 1993

Simultaneous bilateral bleb resection was done through bilateral transaxillary thoracotomy in 10 patients with spontaneous pneumothorax during the period from May 1991 to Novemver 1992 in whom bilateral bulla or bleb was detected with using simple chest X-ray and chest CT scanning. To compare the effectiveness of bilateral transaxillary thoracotomy, we investigated 10 unilateral transaxillary thoracotomy patients with spontaneous pneumothorax and two clinical reports from other institutes which dealt the results of bilateral bleb or bulla resection through median sternotomy also. In bilateral transaxillary thoracotomy group,mean operation time was 115 minute,mean intraoperative bleeding was 329 cc, mean postoperative hospital stay was 7.5 days. Postoperative ABGA[Arterial Blood Gas Analysis] was in normal range and postoperative recovery rates of FVC[Forced Vital Capacity], FEV1[Forced Expiratory Volume at 1 second], TV[Tidal Volume] were 84.3%, 93.4%, 88.7%,respectively. In median sternotomy group,mean operation time was 129 minute,mean intraoperative bleeding was 490 cc, mean postoperative hospital stay was 12.4 days. Postoperative ABGA was in normal range and postoperative recovery rates of FVC, FEV1 were 97.3%, 97.4%, respectively. In unilateral transaxillary thoracotomy group, postoperative ABGA was in normal range also and postoperative recovery rates of FVC, FEV1, TV were 91.6%, 99.0%, 96.0%,respectively. In conclusion, simultaneous bilateral bleb resection through bilateral transaxillary thoracotomy should be considered in pneumothorax patients with bilateral bleb or bulla because of cost-effectiveness[reducing hospital days] and better cosmetic result without any impairment in recovery of respiratory function.