• Clinical and Experimental Pediatrics
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• v.48 no.5
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• pp.488-494
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• 2005

Purpose : To outline the aspects of extubation by birth weight and find the predictors for success/failure at the first extubation in extremely low birth weight infants. Methods : One hundred thirteen extremely low birth weight infants(<1,000 g) who were admitted to NICU at Samsung Seoul Hospital between Jan. 2000 and Jun. 2004 were enrolled. Clinical characteristics that are thought to be related with extubation success or failure were compared with the success and the failure of the first extubation. Results : As the birth weight decreased, extubation success day was significantly delayed : $16{\pm}3day(d)$ in 900-999 g; $20{\pm}3d$ in 800-899 g; $35{\pm}4d$ in 700-799 g; $37{\pm}9d$ in 600-699 g; $49{\pm}12d$ in ${\leq}599g$. 25 out of 113 infants(22%) failed the first extubation. Preterm premature rupture of membrane was associated with extubation success, and air leak was associated with extubation failure, with a borderline significance. Postnatal and corrected age and body weight at the first extubation, nutritional status, and ventilator settings were not associated with extubation success or failure. Extubation success day was significantly delayed, and the incidence of late-onset sepsis and mortality was significant higher in the failure of the first extubation. Conclusion : We could not find significant predictors for success/failure at the first extubation. The failure of the first extubation had an increased risk of late-onset sepsis and death. Further studies are needed to find the predictors for extubation success/failure.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.3
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• pp.75-86
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• 2003

In the near future, the capacity of conventional anaerobic digester is thought to be insufficient because of the increase of the total solids from expansion of intercepting sewer, sewage quantity and direct input of night soil from near apartment districts. The objectives of this study was to investigate the improvement of digestion efficiency using microbial agent(Bio-dh). The system was a pilot-scale, two-staged, anaerobic sludge digestion system. The first-stage digester was heated and mixed. The agitation velocity of the first-stage digester was 120rpm. The second-stage digester was neither heated nor mixed. The Digestion temperature was kept at $35{\pm}1^{\circ}C$ The detention time of digester was 19 days. The dosage of sewage sludge and microbial agent were $0.65m^3/day$ and $0.5{\ell}/day$, respectively. The experiments was run for 25days. Three times a week, $COD_{Mn}$ and SS of effluent, TS, VS, and biogas production rate were measured. Temperature, pH, and alkalinity were measured daily. The results were as follows ; Without microbial agent, digestion efficiencies ranged 46.0%~50.9%(mean=48.6%), with microbial agent(Bio-dh), digestion efficiencies ranged 52.8%~57.3%(mean=54.2%). Consequently, microbial agent(Bio-dh) increased the sludge digestion efficiency about 12%. Also, Without microbial agent, the mean concentration of $COD_{Mn}$ and SS of second-stage digester effluent were 1,639mg/L, 4,888mg/L respectively. With microbial agent, the mean concentration of $COD_{Mn}$ and SS of second-stage digester effluent were 859mg/L, 2,405mg/L respectively. Consequently, microbial agent(Bio-dh) increased the removal efficiency of $COD_{Mn}$ and SS about 47.6% and 50.8%, respectively.

• Journal of Chest Surgery
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• v.43 no.4
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• pp.404-408
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• 2010

Background: Pleural symphysis is regarded as an important treatment option in reducing recurrence rates after surgical treatment of spontaneous pneumothorax. However, there is much debate over the best method for achieving pleural symphysis. We retrospectively compared apical pleurectomy (AP) with mechanical pleural abrasion (MPA). Material and Method: Between January 2000 and December 2007, 83 patients underwent video-assisted thoracoscopic surgery (VATS) for spontaneous pneumothorax. In addition to wedge resection of bullae, MPA was performed in 21 patients (group A) and AP in 62 patients (group B). Result: There were no significant differences in age, gender and site of pneumothorax between the two groups. Operative time was $97{\pm}44$ minutes in group A and $77{\pm}18$ minutes in group B (p>0.05). The mean amount of pleural drainage through the chest tube on the first postoperative day was $156{\pm}87 cc$ in group A and $147{\pm}87 cc$ in group B (p>0.05). There was no mortality or significant morbidity in all patients with the exception of reoperation for bleeding in two patients in group B. In the postoperative course, there were no statistical differences between the two groups in the rate of residual air space, air leak and indwelling time of chest tube, and hospital stay. Mean follow up time was $31.7{\pm}25.3$ months, and the recurrence rate of pneumothorax was 9.5% (2/21) in group A and 6.5% (4/62) in group B, without statistical significance. Conclusion: AP was no more advantageous than MPA in terms of operative time, postoperative course and prevention of recurrent pneumothorax. Therefore, complete resection of bullae and existence of residual bullae are more important factors in reducing the incidence of recurrent pneumothorax than pleural symphysis.

• Journal of Chest Surgery
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• v.41 no.6
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• pp.729-735
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• 2008

Background: This study was performed to evaluate the safety and efficacy of performing additional tetracycline pleurodesis during the thoracoscopic treatment of primary spontaneous pneumothorax. Material and Method: Between March 2004 and December 2007, 91 cases of primary spontaneous pneumothorax were treated by video-assisted thoracoscopic surgery. The thoracoscopic procedures included resection of the blebs and mechanical pleurodesis by scrubbing the parietal pleura. For 27 cases (Tetracycline group, group I), 20 mg/kg tetracycline was instilled into the pleural space through a trocar before closing the chest. The control group (group II) consisted of 64 cases of primary spontaneous pneumothorax for which the same thoracoscopic procedures alone were performed during the same study period. Result: There was no significant difference between the two groups in terms of the demographic data, the operative findings and the operation time. The percentage of cases that needed intravenous analgesics and the duration of intravenous analgesics were comparable in both groups. There was no significant difference in the duration of air leaks and complications between the two groups. The patients treated with tetracycline pleurodesis had a longer period of postoperative chest drainage (4.2 days vs 3.5 days, respectively, p=0.03) and hospitalization (5.0 days vs 4.0 days, respectively, p=0.006). During the follow up period, the ipsilateral recurrence rate was much lower for the patients who were treated with tetracycline pleurodesis (0% vs 10.9%, respectively, p=0.099), and freedom from recurrence tended to be more favorable for group I (p=0.077), although this was not statistically significant. Conclusion: Additional tetracycline pleurodesis during thoracoscopic treatment for primary spontaneous pneumothorax caused prolongation of chest drainage and a prolonged hospital stay. However, further investigations are needed because tetracycline pleurodesis can be performed safely without serious complications and it showed a distinct tendency to reduce the rate of recurrence.

• Clinical and Experimental Pediatrics
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• v.46 no.11
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• pp.1073-1079
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• 2003

Purpose : Recently there has been a decrease in ventilator care rate and duration of very low birth weight infants(VLBWI) in Fatima Hospital. The aims of this study were to survey the frequency and duration of ventilation in VLBWI and to develop a non-invasive neonatal intensive care unit (NICU) policy. Methods : We performed a retrospective study of 284 newborn of infants less than 1,500 gm admitted to NICU and discharged from January 1998 to December 2001. Patients were intubated or applied continuous positive airway pressure(CPAP) via nasal prong immediately after presenting signs of respiratory distress. We analyzed epidemiologic data to study the changes in ventilator care rate, duration and outcome of ventilator care groups. Results : Of 284 newborn infants, 146 required invasive management, such as endotracheal intubation and assisted ventilation. The characteristics, the severity of clinical symptoms and laboratory findings in ventilator care groups at birth showed no significant differences. The annual proportion of infants requiring assisted ventilation decreased according to increasing gestational age. The median duration of ventilation decreased markedly from 6.0 days in 1998 to 2.7 days in 2001. Final complications and outcomes in ventilator care groups showed no significant differences. Conclusion : Our study shows a significant reduction in the invasiveness of the treatment of VLBW infants, which was not associated with an increased mortality or morbidity. A non-invasive strategy for the VLBW infant with minimal to moderate respiratory distress after birth in NICU is better than immediate invasive management. Non-invasive nasal CPAP is a simpler and safer method than invasive assisted ventilation.

• Clinical and Experimental Pediatrics
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• v.53 no.1
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• pp.21-27
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• 2010

Purpose : In contrast with traditional time-cycled, pressure-limited ventilation, during volume-controlled ventilation, a nearly constant tidal volume is delivered with reducing volutrauma and the episodes of hypoxemia. The aim of this study was to compare the efficacy of pressure-regulated, volume controlled ventilation (PRVC) to Synchronized intermittent mandatory ventilation (SIMV) in VLBW infants with respiratory distress syndrome (RDS).Methods : 34 very low birth weight (VLBW) infants who had RDS were randomized to receive either PRVC or SIMV with surfactant administration : PRVC group (n=14) and SIMV group (n=20). We compared peak inspiratory pressure (PIP), duration of mechanical ventilation, and complications associated with ventilation, respectively with medical records. Results : There were no statistical differences in clinical characteristics between the groups. After surfactant administration, PIP was significantly lower during PRVC ventilation for 48hrs and accumulatevive value of decreased PIP was higher during PRVC ventilation for 24hrs (P<0.05). Duration of ventilation and incidence of complications was no significant difference. Conclusion : PRVC is the mode in which the smallest level of PIP required to deliver the preset tidal volume in VLBW infants with RDS, adaptively responding to compliance change in lung after surfactant replacement.

• Economic and Environmental Geology
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• v.53 no.1
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• pp.23-32
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• 2020

Geological CO₂ sequestration is a global warming response technology to limit atmospheric emissions by injecting CO₂ captured on a large scale into deep geological formations. The presented results concern mineralogical and hydrogeological investigations (FE-SEM, XRD, XRF, and MICP) of mudstone samples from drilling cores of the Pohang basin, which is the research area for the first demonstration-scale CO₂ storage project in Korea. They aim to identify the mineral properties of the mudstone constituting the caprock and to quantitatively evaluate the hydrogeologic sealing capacity that directly affects the stability and reliability of geological CO₂ storage. Mineralogical analysis showed that the mudstone samples are mainly composed of quartz, K-feldspar, plagioclase and a small amount of pyrite, calcite, clay minerals, etc. Mercury intrusion capillary pressure analysis also showed that the samples generally had uniform particle configurations and pore distribution and there was no distinct correlation between the estimated porosity and air permeability. The allowable CO₂ column heights based on the estimated pore-entry pressures and breakthrough pressures were found to be significantly higher than the thickness of the targeting CO₂ injection layer. These results showed that the mudstone layers in the Yeongil group, Pohang basin, Korea have sufficient sealing capacity to suppress the leakage of CO₂ injected during the demonstration-scale CO₂ storage project. It should be noticed, however, that the applicability of results and analyses in this study is limited by the lack of available samples. For rigorous assessment of the sealing efficiency for geological CO₂ storage operations, significant efforts on collection and multi-aspect evaluation for core samples over entire caprock formations should be accompanied.

• Journal of Chest Surgery
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• v.40 no.4 s.273
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• pp.292-296
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• 2007

Background: This retrospective study was undertaken to assess the effectiveness of the 8-French (Fr) catheter ($Pleuracan^{(R)}$) for the initial treatment of primary spontaneous pneumothorax. Material and Method: Between July 2004 and July 2006, 59 patients (72 cases) underwent a closed thoracostomy for primary spontaneous pneumothorax. We divided these patients into two groups: group T (large bore (>20 Fr) chest tube group) and group P ($Pleuracan^{(R)}$ group). Result: Initially, the $Pleuracan^{(R)}$ catheters were inserted in 41 cases. There were four catheter malfunctions (9.8%) : three cases had a subsequent closed thoracostomy with a large bore chest tube. Ultimately, there were 34 cases in group T and 38 cases in group P. There were no significant differences in indwelling catheter time ($T:\;2.1{\pm}1.5\;days,\;P:\;2.1{\pm}1.3\;days$), hospital stay ($T:\;6.4{\pm}5.4\;days,\;P:\;5.2{\pm}2.9\;days$) and complications (T: 3%, P: 0%) between the two groups. The percentage of cases that needed intravenous analgesics in group P was 60% (23/38); this was significantly lower than the number for group T (90%, 31/34) (p=0.003). In a subgroup of patients that did not undergo bullectomy(T: 17 cases, P: 19 cases), there were no significant differences in the duration of air leakage ($T:\;0.5{\pm}0.7\;days,\;P:\;0.5{\pm}1.2\;days$) and in the percentage of patients with complete lung re-expansion (T: 94%, P: 84%) between the two groups. Conclusion: Application of the $Pleuracan^{(R)}$ catheter for the initial treatment of primary spontaneous pneumothorax was as effective as the large bore chest tube.

• Journal of Chest Surgery
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• v.42 no.5
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• pp.615-623
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• 2009

Background: We evaluated the feasibility and the efficacy of Video-Assisted Thoracic Surgery (VATS) lobectomy for treating patients with non-small cell lung cancer (NSCLC) and we compared the outcomes of VATS lobectomy with those of open lobectomy. Material and Method: From 2003 to March 2008, 133 NSCLC patients underwent VATS lobectomy. The patients were selected on the basis of having clinical stage I disease on the chest CT and PET scan. The outcomes of 202 patients who underwent open lobectomy (OL group) for clinical stage I NSCLC were evaluated to compare their results with those of the patients who underwent VATS lobectomy (the VL group). Result: The number of females and the number of patients with adenocarcinoma and stage IA disease were greater in VL group (p<0.05). There was no operative mortality or major complications in the VL group. Conversion to thoracotomy was needed in 8 cases (6%), which was mostly due to bleeding. The chest tube indwelling time and the length of the postoperative hospital stay were significantly shorter in the VL group (p<0.001). The number of dissected lymph nodes and the size of tumor were significantly smaller in the VL group (p<0.001). For the pathologic stage I patients, there was no significant difference in the three-year survival rates between the two groups (p=0.15). Conclusion: VATS lobectomy is a safe procedure with low operative mortality and morbidity. VATS lobectomy is feasible for early stage NSCLC and it provides outcomes that are comparable to those for open lobectomy. Further long-term data are needed.

• Journal of Chest Surgery
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• v.43 no.2
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• pp.144-149
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• 2010

Background: Many studies have demonstrated the various therapeutic options for treating hemoptysis caused by inflammatory lung disease. However, there is debate over the surgical management of the ongoing hemoptysis. Therefore, we evaluated the clinical results of pulmonary resection that was done due to hemoptysis in patients with concomitant inflammatory lung disease. Material and Method: We performed a retrospective analysis of 75 patients who received pulmonary resection for hemoptysis and concomitant inflammatory lung disease between 2001 and 2007. The mean age was $52.1{\pm}12.5$ years old, and the male; female ratio was 52：23. Result: The underlying disease was aspergilloma in 30 patients (40%), pulmonary tuberculosis in 20 patients, bronchiectasis in 18 patients and other causes in 7 patients. The surgical treatment included lobectomy in 55 patients, bilobectony in 2 patients, pneumonectomy in 17 patients and wedge resection in 1 patient. There were 3 early deaths, and the causes of death were pneumonia in 1 patient and BPF in 2 patients. The early mortality was statistically higher for such risk factors as a preoperative Hgb level <10 g/dL, COPD and an emergency operation. Conclusion: In conclusion, pulmonary resection for treating hemoptysis showed the acceptable range of mortality and it was an effective method for the management of hemoptysis in patients with inflammatory lung disease. However, relatively high rates of mortality and morbidity were noted for an emergency operation, and so meticulous care is needed in this situation.