• 제목/요약/키워드: positive pressure ventilation

검색결과 101건 처리시간 0.024초

신경계 중환자실에서 기계호흡 그래프 파형 감시와 분석 (Monitoring and Interpretation of Mechanical Ventilator Waveform in the Neuro-Intensive Care Unit)

  • 박진
    • 대한신경집중치료학회지
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    • 제11권2호
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    • pp.63-70
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    • 2018
  • Management of mechanical ventilation is essential for patients with neuro-critical illnesses who may also have impairment of airways, lungs, respiratory muscles, and respiratory drive. However, balancing the approach to mechanical ventilation in the intensive care unit (ICU) with the need to prevent additional lung and brain injury, is challenging to intensivists. Lung protective ventilation strategies should be modified and applied to neuro-critically ill patients to maintain normocapnia and proper positive end expiratory pressure in the setting of neurological closed monitoring. Understanding the various parameters and graphic waveforms of the mechanical ventilator can provide information about the respiratory target, including appropriate tidal volume, airway pressure, and synchrony between patient and ventilator, especially in patients with neurological dysfunction due to irregularity of spontaneous respiration. Several types of asynchrony occur during mechanical ventilation, including trigger, flow, and termination asynchrony. This review aims to present the basic interpretation of mechanical ventilator waveforms and utilization of waveforms in various clinical situations in the neuro-ICU.

후천성 기관확장증 (Acquired Tracheal Dilatation)

  • 최종욱;김용환;김혜정;이승훈;최건
    • 대한기관식도과학회지
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    • 제3권1호
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    • pp.185-187
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    • 1997
  • Acquired tracheal dilatation is a state of abnormal tracheal dilatation developing from various causes. Tracheomalacia and tracheal dilatation can develop in respiratory distress patients with prolonged endotracheal intubation with assisted positive-pressure ventilation due to positive airway pressure and high cuff pressure. The authors have recently experienced one case of respiratory failure, cardiac arrest, and whole body emphysema after tracheostomy and portex tube insertion were performed to patient with the endotracheal intubation with assisted positive-pressure ventilation for two weeks in the septic shock resulted from colon perforation, who developed tracheal dilatation. We summarize diagnostic and therapeutic strategies of acquired tracheal dilatation for the prevention of emergency status and the management for that patients.

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The Impact of Double-Skin Façades on Indoor Airflow in Naturally Ventilated Tall Office Buildings

  • Yohan, Kim;Mahjoub M. Elnimeiri;Raymond J. Clark
    • 국제초고층학회논문집
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    • 제12권2호
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    • pp.129-136
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    • 2023
  • Natural ventilation has proven to be an effective passive strategy in improving energy efficiency and providing healthy environments. However, such a strategy has not been commonly adopted to tall office buildings that traditionally rely on single-skin façades (SSFs), due to the high wind pressure that creates excessive air velocities and occupant discomfort at upper floors. Double-skin façades (DSFs) can provide an opportunity to facilitate natural ventilation in tall office buildings, as the fundamental components such as the additional skin and openings create a buffer to regulate the direct impact of wind pressure and the airflow around the buildings. This study investigates the impact of modified multi-story type DSFs on indoor airflow in a 60-story, 780-foot (238 m) naturally ventilated tall office building under isothermal conditions. Thus, the performance of wind effect related components was assessed based on the criteria (e.g., air velocity and airflow distribution), particularly with respect to opening size. Computational fluid dynamics (CFD) was utilized to simulate outdoor airflow around the tall office building, and indoor airflow at multiple heights in case of various DSF opening configurations. The simulation results indicate that the outer skin opening is the more influential parameter than the inner skin opening on the indoor airflow behavior. On the other hand, the variations of inner skin opening size help improve the indoor airflow with respect to the desired air velocity and airflow distribution. Despite some vortexes observed in the indoor spaces, cross ventilation can occur as positive pressure on the windward side and negative pressure on the other sides generate productive pressure differential. The results also demonstrate that DSFs with smaller openings suitably reduce not only the impact of wind pressure, but also the concentration of high air velocity near the windows on the windward side, compared to SSFs. Further insight on indoor airflow behaviors depending on DSF opening configurations leads to a better understanding of the DSF design strategies for effective natural ventilation in tall office buildings.

Influence of ventilation rate on the aerodynamic interference between two extra-large indirect dry cooling towers by CFD

  • Ke, S.T.;Liang, J.;Zhao, L.;Ge, Y.J.
    • Wind and Structures
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    • 제20권3호
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    • pp.449-468
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    • 2015
  • Current wind-resistance designs of large-scale indirect dry cooling towers (IDCTs) exclude an important factor: the influence of the ventilation rate for radiator shutter on wind loads on the outer surfaces of the tower shell. More seemingly overlooked aspects are the effects of various ventilation rates on the wind pressure distribution on the tower surfaces of two IDCTs, and the feature of the flow field around them. In order to investigate the effects of the radiator shutter ventilation rates on the aerodynamic interference between IDCTs, this paper established the numerical wind tunnel model based on the Computational Fluid Dynamic (CFD) technology, and analyzed the influences of various radiator shutter ventilation rates on the aerodynamic loads acting upon a single and two extra-large IDCTs during building, installation, and operation stages. Through the comparison with the results of physical wind tunnel test and different design codes, the results indicated that: the influence of the ventilation rate on the flow field and shape coefficients on the outer surface of a single IDCT is weak, and the curve of mean shape coefficients is close to the reference curve provided by the current design code. In a two-tower combination, the ventilation rate significantly affects the downwind surface of the front tower and the upwind surface of the back tower, and the larger positive pressure shifts down along the upwind surface of the back tower as the ventilation rate increases. The ventilation rate significantly influences the drag force coefficient of the back tower in a two-tower combination, the drag force coefficient increases with the ventilation rate and reaches the maximum in a building status of full ventilation, and the maximum drag coefficient is 11% greater than that with complete closure.

새송이버섯 병재배에서 환기방법이 이산화탄소 농도 및 자실체형성에 미치는 영향 (Effects of Various Ventilation Systems on the Carbon Dioxide Concentration and Fruiting Body Formation of King Oyster Mushroom (Pleurotus eryngii) Grown in Culture Bottles)

  • 이현욱;안미정;이신우;이철호
    • 생명과학회지
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    • 제17권1호
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    • pp.82-90
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    • 2007
  • 새송이버섯 재배에서 환기방법이 실내의 이산화탄소 농도 및 자실체형성에 미치는 영향을 알아보기 위하여 평압형, 양압형, 음압형, 복합형의 4종의 환기방법을 사용하여 환기효율, 재배효율 및 생리장해발생정도를 포장에서 조사하였다. 그 결과 복합형의 경우, 실내 이산화탄소 농도가 평압형의 경우 1,400 ppm인 것에 비해 800 ppm으로서 현저하게 낮았고, 기류발생정도도 상대적으로 적어 환기효율이 가장 높은 것으로 나타났다. 대의 길이, 갓의 직경, 품질, 수량 등의 재배효율이 복합형에서 가장 높았으며, 수확소요일수가 단축 되었다. 생리장해의 발생에 있어서는, 세균점액증상, 비늘대증상 및 굴곡대증상의 경우에서는 환기방법에 따라 큰 차이를 보이지 않았으나, 오뚝이증상, 진무름증상 및 갈반증상은 이산화탄소 농도가 다른 환기방법에 비해 낮았던 복합형과 음압형에서 현저하게 줄어드는 경향을 보였다. 전체적으로 볼 때, 평압형 환기방법은 환기효율이 낮아 실내 이산화탄소농도를 유효하게 밖으로 배출해 내지 못함으로서 품질과 수량을 현저하게 떨어뜨리고, 생리장해의 발생을 유도하는 결과를 초래하였으며, 양압형 또한 평압형에 비해 효율성이 다소 높은 경향을 보였으나, 이들 2종은 새송이 버섯의 연중재배에 이용되는 환기방법으로 부적절한 것으로 나타났다. 음압형의 경우 상대적으로 효율성이 높은 환기방법으로서 어느 정도 도입의 가능성을 시사하고 있으나, 복합형이 환기효율, 재배효율 및 생리장해억제효과가 가장 우수한 것으로 조사되어, 새송이버섯 재배에서 복합형 환기방법을 도입할 경우, 품질향상과 생산성향상은 물론 연중 안전재배를 기대할 수 있을 것으로 사료된다. 도움이 되리라 생각된다.리고 실험에 사용된 송신부 및 수신부를 사진으로 보였으며, 이것을 이용하여 통신 수신율을 분석하였다. 주파수에서 측정된 Type 1 안테나의 전기적 성능은 원형 도체 배열을 10개 적층(disk10)하였을 때, 15.65 dBi의 최대 안테나 이득과 11.4 dB 이상의 입력 반사 손실 성능을 보여 주었으며, 다층 원형 도체 배열 구조에 의해 약 5 dB의 이득 향상 효과를 얻을 수 있었다. 또한, 원형 도체를 12개 적층하였을 때, 외곽 유전체 링 효과에 의해 Type 1 안테나는 Type 2 안테나보다 상대적으로 약 1.35 dB 만큼 이득이 더 높았으며, 각 안테나의 3 dB 빔 폭은 각각 약 $28^{\circ}$$36^{\circ}$로 측정되었다.. 그러나 기흉 발생 당일은 기흉이 발생하지 않은 날 당일보다 전일 대비 평균 기온이 높고(0.533 vs. $-0.103^{\circ}C$, RR 1.141, Cl $1.038{\sim}l.255$, p=0.006), 기온상승폭도 컸다(9.209 vs. $7.754^{\circ}C$, RR 1.123, Cl $1.061{\sim}1.190$, p=0.000). 결론: 본 연구의 결과를 통해 저자들은 기압이 상승한 뒤 기온이 상승했다. 하강하는 약 4일간의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수

Moving Mesh를 이용한 PCV 밸브의 내부유동 수치해석 (A numerical analysis for internal fluid flow of a PCV valve by using moving mesh)

  • 이종훈;최윤환;이연원
    • 동력기계공학회지
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    • 제9권2호
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    • pp.40-44
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    • 2005
  • A great deal of exhaust gas inside a combustion room goes out through exhaust pipe but residual gas, is called "Blowby gas", enters the crankcase through a small gap between the piston and the cylinder wall. Here, if the crankcase isn't vented, this causes many bad effects such as lubricant oil contamination, corrosion by that and crankcase explosion by rising pressure. So, most automobiles are constituted with a PCV (Positive Crankcase Ventilation) system to prevent previous problems. PCV valve is the most important part in this ventilation system. When companies are manufacturing new engines, engineers are designing it depending on their experiments than theoretical knowledge. Mush efforts and times are needed for new development. This study will show quantitative results to increase the possibilities of reduction of developing time.

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Moving Mesh를 이용한 PCV 밸브의 내부유동 수치 해석 (A numerical analysis for internal fluid flow of a PCV valve by using moving mesh)

  • 이종훈;리리;김영국;최윤환;이연원
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 2004년도 추계 학술대회논문집
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    • pp.19-24
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    • 2004
  • A great deal of exhaust gas inside a combustion room goes out through exhaust pipe but residual gas, is called 'Blow by gas', enters the crankcase through a small gap between the piston and the cylinder wall. Here, if the crankcase isn't vented, this causes many bad effects such as lubricant oil contamination, corrosion by that and crankcase explosion by rising pressure. So most automobiles are constituted with a PCV(Positive Crankcase Ventilation) system to prevent previous problems. PCV valve is the most important part in this ventilation system. When companies are manufacturing new cases, engineers are designing it depending on their experiments than theoretical knowledges. Much efforts and times are needed for new development. This study will show quantitative results to increase the possibilities.

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PCV(Positive Crankcase Ventilation) 밸브의 유동특성에 관한 수치해석 (Computational Analysis of Flow Characteristics of a PCV Valve)

  • 이종훈;최윤환;이연원
    • 한국자동차공학회논문집
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    • 제13권4호
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    • pp.66-73
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    • 2005
  • A great deal of exhaust gas inside a combustion room goes out through exhaust pipe. But residual gas 'Blowby gas' enters the crankcase through a small gap between the piston and the cylinder wall. Here, if the blowby gas isn't vented, this causes many bad efffcts such as lubricant oil contamination, corrosion by that and crankcase explosion by rising pressure. So most automobiles are constituted with a PCV(Positive Crankcase Ventilation) system to prevent previous problems. PCV valve is the most important part in this ventilation system. When companies are manufacturing new cases, engineers are designing it depending on their experiments than theoretical knowledges. Much efforts and times are needed for new development. This study will show quantitative results to increase the possibilities for the optimal design.

The Utility of Non-Invasive Nasal Positive Pressure Ventilation for Acute Respiratory Distress Syndrome in Near Drowning Patients

  • Kim, June Hyeong;Sun, Kyung Hoon;Park, Yong Jin
    • Journal of Trauma and Injury
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    • 제32권3호
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    • pp.136-142
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    • 2019
  • Purpose: Near drowning refers to immediate survival after asphyxia due to submersion or immersion in water, which is a crucial public safety problem worldwide. Acute lung injury or acute respiratory distress syndrome (ARDS) is a common complication of near drowning. The purpose of this study was to investigate the feasibility and effectiveness of noninvasive nasal positive pressure ventilation (NINPPV). Methods: This retrospective study was conducted at a tertiary emergency department. NINPPV was administered for moderate ARDS caused by submersion or immersion in patients who were older than 18 years, from January 2015 to December 2018. We collected the demographic (age, sex, length of hospital stay, and outcome), laboratory (arterial blood gas, lactate, oxygen saturation, partial pressure of oxygen divided by the fraction of inspired oxygen, complete blood count, blood urea nitrogen, and creatinine), and clinical data (acute lung injury index and ventilator failure) of the patients. A statistical analysis was performed using Statistical Package for the Social Sciences version 20.0 for Windows. Results: NINPPV treatment was provided to 57 patients for near drowning, 45 of whom (78.9%) were successfully treated without complications; in 12 (21.1%), treatment was changed to invasive mechanical ventilation within 48 hours due to ARDS or acute kidney injury. NINPPV treatment was successful in 31 (75.6%) out of 41 sea-water near drowning patients. They were more difficult to treat with NINPPV compared with the fresh-water near drowning patients (p<0.05). Conclusions: NINPPV would be useful and feasible as the initial treatment of moderate ARDS caused by near drowning.

The Long-term Efficacy of Domiciliary Noninvasive Positive-Pressure Ventilation in Chronic Obstructive Pulmonary Disease: A Meta-Analysis of Randomized Controlled Trials

  • Park, So Young;Yoo, Kwang Ha;Park, Yong Bum;Rhee, Chin Kook;Park, Jinkyeong;Park, Hye Yun;Hwang, Yong Il;Park, Dong Ah;Sim, Yun Su
    • Tuberculosis and Respiratory Diseases
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    • 제85권1호
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    • pp.47-55
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    • 2022
  • Background: We evaluated the long-term effects of domiciliary noninvasive positive-pressure ventilation (NIPPV) used to treat patients with chronic obstructive pulmonary disease (COPD). Methods: Databases were searched to identify randomized controlled trials of COPD with NIPPV for longer than 1 year. Mortality rates were the primary outcome in this meta-analysis. The eight trials included in this study comprised data from 913 patients. Results: The mortality rates for the NIPPV and control groups were 29% (118/414) and 36% (151/419), suggesting a statistically significant difference (risk ratio [RR], 0.79; 95% confidence interval [CI], 0.65-0.95). Mortality rates were reduced with NIPPV in four trials that included stable COPD patients. There was no difference in admission, acute exacerbation and quality of life between the NIPPV and control groups. There was no significant difference in withdrawal rates between the two groups (RR, 0.99; 95% CI, 0.72-1.36; p=0.94). Conclusion: Maintaining long-term nocturnal NIPPV for more than 1 year, especially in patients with stable COPD, decreased the mortality rate, without increasing the withdrawal rate compared with long-term oxygen treatment.