• 상하수도학회지
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• 제22권6호
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• pp.681-687
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• 2008

It is well known that the water infiltration rate depends on soil properties such as soil water content, water head, capillary suction, density, hydraulic conductivity, and porosity. However, most of proposed infiltration models assume that the air phase is continuous and in equilibrium with the atmosphere or air compression and air entrapment on infiltration was not considered. This study presents experimental results on unsaturated water infiltration to relate air entrapment and hydraulic conductivity function based on soil air properties. The objectives of this study were to measure change of soil air pressure ahead of wetting front under air drain and air confined condition to find the confined air effect on infiltration rate, to reduce the entrapped air volume related with soil air pressure to increase the soil permeability, and to make a basis of infiltration process model for the purpose of improvement of infiltration rate in the homogeneous soil column. The results of the work show that soil air pressure increases according to increasement of the saturated soil depth rather than the wetting front depth during infiltration process.

• 한국지반공학회논문집
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• 제29권3호
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• pp.15-27
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• 2013

기존 성토재하 방식의 연약지반 개량공법에서 제기된 여러 가지 문제에 의해 진공압 재하방식의 개량공법이 개발되었으며, 국내 적용사례가 증가하고 있다. 현장에서의 침하관리시 동일한 하중을 재하하였을 경우의 진공압재하공법과 성토재하공법에 대한 침하량 비교 연구가 진행되어 왔다. 본 연구에서는 두 공법의 발생침하량에 관한 이론 및 사례 연구를 수행하였다. 그 결과 연약지반 개량을 위해 진공압이 적용되면 내향의 수평변위가 발생하고 동일한 하중재하 대비 침하량이 감소하였다. Hooke의 탄성이론을 바탕으로 한 경우 0.54~0.67, 국내 설계기준에서는 0.50~0.75, 과거 국내 시공사례를 바탕으로 한 경우 0.91, 실내시험을 바탕으로 한 경우 0.81, 탄성론과 체적압축계수법을 바탕으로 한 경우 0.75, 최근 국내 대심도 시공 사례의 경우 0.77~0.93의 범위를 보이는 것으로 나타났다.

• 기본간호학회지
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• 제12권3호
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• pp.395-403
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• 2005

Purpose: Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen in the intensive care units (ICUS). The purpose of this case-control study is to identify risk factors for acquisition of MRSA during ICU stays in patients with and without MRSA. Method: The study was conducted in a 16 beds-neurosurgical intensive care unit of a 2200-bed tertiary care university hospital in Seoul, Korea. Medical record and Critical Classification Scoring System were reviewed retrospectively in patients who were admitted more than 3 days from August 1, 2003 to May 30, 2004. Cases and controls were matched for age and gender. The obtained specimens were nasal swab and sputum. Result: There were 950 patients' admissions during the period. Among them, MRSA was isolated from twenty-three patients who were considered as hospital acquired. Artificial airway (p=.045), frequency of suction (p=.002), nasogastric tube (p=.004), wound drain (p=.045), and vancomycin (p=.019) were risk factors for MRSA acquisition in univariate analysis. Frequency of suction (p=.012, OR 3.5) was revealed as the only risk factor in multivariate conditional logistic regression. Conclusion: Our findings give support to recent studies that suggest that frequent physical contact maγ increase the nosocomial acquisition of MRSA in a neurosurgical ICU.

• Archives of Plastic Surgery
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• 제45권5호
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• pp.449-457
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• 2018

Background Although previous studies have focused on determining prognostic and causative variables associated with fistula-related complications after head and neck reconstructive surgery, only a few studies have addressed preventive measures. Noting that pooled saliva complicates wound healing and precipitates fistula-related complications, we devised a continuous suction system to remove saliva during early postoperative recovery. Methods A continuous suction system was implemented in 20 patients after head and neck reconstructive surgery between January 2012 and October 2017. This group was compared to a control group of 16 patients at the same institution. The system was placed orally when the lesion was on the anterior side of the retromolar trigone area, and when glossectomy or resection of the mouth floor was performed. When the orohypopharynx and/or larynx were eradicated, the irrigation system was placed in the pharyngeal area. Results The mean follow-up period was $9.2{\pm}2.4$ months. The Hemovac system was applied for an average of 7.5 days. On average, 6.5 days were needed for the net drain output to fall below 10 mL. Complications were analyzed according to their causes and rates. A fistula occurred in two cases in the suction group. Compared to the control group, a significant difference was noted in the surgical site infection rate (P<0.031). Conclusions Clinical observations showed reduced saliva pooling and a reduction in the infection rate. This resulted in improved wound healing through the application of a continuous suction system.

• Archives of Plastic Surgery
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• 제47권1호
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• pp.33-41
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• 2020

Background Closed-suction drains are widely used in expander-based breast reconstruction. These drains are typically removed using a volume-based criterion. The drainage volume affects the hospital stay length and the recovery time. However, few studies have analyzed the factors that influence drainage volume after expander-based breast reconstruction. Methods We retrospectively analyzed data regarding daily drainage from patients who underwent expander-based breast reconstruction between April 2014 and January 2018 (159 patients, 176 expanders). Patient and operative factors were analyzed regarding their influence on total drainage volume and drain placement duration using univariate and multivariate analyses and analysis of variance. Results The mean total drainage volume was 1,210.77±611.44 mL. Univariate analysis showed correlations between total drainage volume and age (B=19.825, P<0.001), body weight (B=17.758, P<0.001), body mass index (B=51.817, P<0.001), and specimen weight (B=1.590, P<0.001). Diabetes history (P<0.001), expander type (P<0.001), and the surgical instrument used (P<0.001) also strongly influenced total drainage. The acellular dermal matrix type used did not affect total drainage (P=0.626). In the multivariate analysis, age (B=11.907, P=0.004), specimen weight (B=0.927, P<0.001), and expander type (B=593.728, P<0.001) were significant predictors of total drainage. Conclusions Our findings suggest that the total drainage and the duration of drain placement needed after expander-based breast reconstruction can be predicted using preoperative and intraoperative data. Patient age, specimen weight, and expander type are important predictors of drainage volume. Older patients, heavier specimens, and use of the Mentor rather than the Allergan expander corresponded to a greater total drainage volume and a longer duration of drain placement.

• 한국지반공학회논문집
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• 제28권11호
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• pp.41-52
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• 2012

석션드레인공법은 연직배수재를 통해 연약지반에 직접 진공압을 가하게 되므로 진공압에 의해 배수재 주변의 경화영역이 형성된다. 이러한 경화영역은 지반의 투수성을 저하시켜 간극수 배출 효율이 급격히 저하된다. 본 연구에서는 배수효율을 저하시키는 요인 중 하나인 경화영역을 최소화하기 위해 단계 진공압을 고려하였다. 단계 진공압(-20kPa, -40kPa, -60kPa, -80kPa) 적용 기간이 경화영역과 지반개량 효과에 미치는 영향을 평가하기 위해 부산 해성 점토를 대상으로 단계별로 진공압 적용일자를 달리하여 실내시험을 수행하였다. 강도(CPT) 및 함수비 시험과 이론적 검증을 통해 경화영역의 범위는 약 7.0cm 이내이고, 경화영역 내에서의 투수계수 저하비는 약 2.0~4.0으로 평가되었다. 또한, 일괄적인 진공재하방식보다는 단계재하방식이 최종침하량 측면에서 더 우수한 것으로 나타났으며, 단계별 진공압의 적용기간도 대상 점토의 특성을 고려하여 결정되어야 함을 보였다. 수치해석 결과 경화영역을 고려하는 것이 실측값에 유사한 결과를 도출할 수 있음을 확인하였다.

• Tuberculosis and Respiratory Diseases
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• 제81권2호
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• pp.106-115
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• 2018

Chest tube insertion is a common procedure usually done for the purpose of draining accumulated air or fluid in the pleural cavity. Small-bore chest tubes (${\leq}14F$) are generally recommended as the first-line therapy for spontaneous pneumothorax in non-ventilated patients and pleural effusions in general, with the possible exception of hemothoraces and malignant effusions (for which an immediate pleurodesis is planned). Large-bore chest drains may be useful for very large air leaks, as well as post-ineffective trial with small-bore drains. Chest tube insertion should be guided by imaging, either bedside ultrasonography or, less commonly, computed tomography. The so-called trocar technique must be avoided. Instead, blunt dissection (for tubes >24F) or the Seldinger technique should be used. All chest tubes are connected to a drainage system device: flutter valve, underwater seal, electronic systems or, for indwelling pleural catheters (IPC), vacuum bottles. The classic, three-bottle drainage system requires either (external) wall suction or gravity ("water seal") drainage (the former not being routinely recommended unless the latter is not effective). The optimal timing for tube removal is still a matter of controversy; however, the use of digital drainage systems facilitates informed and prudent decision-making in that area. A drain-clamping test before tube withdrawal is generally not advocated. Pain, drain blockage and accidental dislodgment are common complications of small-bore drains; the most dreaded complications include organ injury, hemothorax, infections, and re-expansion pulmonary edema. IPC represent a first-line palliative therapy of malignant pleural effusions in many centers. The optimal frequency of drainage, for IPC, has not been formally agreed upon or otherwise officially established.

• 한국지반공학회논문집
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• 제26권11호
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• pp.75-87
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• 2010

불포화토에 강우가 지속되면 토체내 간극수압이 상승하게 된다. 따라서 토층의 포화로 인해 강도가 저하되고, Suction압이 균형을 이루는 임계 깊이까지 Wetting Front가 하강하여 사면붕괴가 발생한다. 지중 간극수압을 제어할 수 있다면 강도저감을 방지함으로써 사면안정을 유지할 수 있을 것이다. 본고는 지중 간극수를 흡수하여 배출할 수 있는 흡수관 설계를 시도하여 실험성과로 그 가능성을 제시하였다. 흡수관은 사면안정을 위한 보조공법으로 활용하는 것이 효과적일 것이다.

• 한국지반신소재학회논문집
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• 제21권1호
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• pp.11-21
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• 2022

본 연구에서는 개별진공압밀공법과 침투압밀공법의 단점을 보완하여 새로운 연약지반 개량공법인 개별진공 침투압밀공법을 개발하여 수치해석을 통해 지반 공학적 거동을 예측하였다. 개별진공 침투압밀공법을 적용할 경우, 대수층이 개량 대상층 중간 또는 하단에 위치하여 피압 대수층인 경우 침하 촉진 및 발생 침하량 증대 효과가 높았다. 대수층에서의 양수량은 일정 수준 이상 되면 침하 거동에 영향을 미치지 않는 것으로 나타났다. 성토체 내측이나 외측 등 다양한 위치에서 진공 양수정을 설치하여도 침하 및 수평 변위 차이는 미미하였다. 개별진공압밀과 병행하는 경우, 진공압이 적용되는 초기 침하는 진공압의 크기에 영향을 받았지만, 최종 침하량은 진공압의 영향이 미미한 것으로 예측되었다. 또한, 두 공법을 동시에 진행하는 것이 침하속도가 가장 빠르고, 내향 변위도 큰 것으로 예측하였다. 본 연구에서 개발한 공법은 매우 빠른 시점에 목표 침하량에 도달할 수 있으므로 연직배수재 배치 간격을 늘릴 수 있어 경제성을 확보할 수 있는 것으로 확인되었다.

• Journal of Korean Neurosurgical Society
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• 제39권5호
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• pp.335-339
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• 2006

Objective : The authors present eight cases of immediate post-operative epidural hematomas[EDHs] adjacent to the craniotomy site, describe clinical details of them, and discuss their pathogenesis. Methods : Medical records of eight cases were retrospectively reviewed and their clinical data, operation records, and radiological findings analyzed. Any risk factors of the EDHs were searched. Results : In 5 of 8 cases, adjacent EDHs developed after craniotomies for the surgical removal of brain tumors. Three cases of adjacent EDHs developed after a pterional approach and neck clipping of a ruptured anterior communicating artery aneurysm, a ventriculoperitoneal shunt, and a craniotomy for a post-traumatic EDH, respectively. In all eight cases, brain computed tomography[CT] scans checked immediately or a few hours after the surgery, revealed large EDHs adjacent to the previous craniotomy site, but there was no EDH beneath the previous craniotomy flap. After emergent surgical removal of the EDHs, 7 cases demonstrated good clinical outcomes, with one case yielding a poor result. Conclusion : Rapid drainage of a large volume of cerebrospinal fluid or intra-operative severe brain collapse may separate the dura from the calvarium and cause postoperative EDH adjacent to the previous craniotomy site. A high-pressure suction drain left in the epidural space may contribute to the pathogenesis. After the craniotomy for brain tumors or intracranial aneurysms, when remarkable brain collapse occurs, an immediate postoperative brain CT is mandatory to detect and adequately manage such unexpected events as adjacent EDHs.