Sample records for boxes dehumidifiers ventilation

  1. Liquid Desiccant Regenerable Filters For Indoor Environmental Quality and Security

    DTIC Science & Technology

    2003-11-19

    Blake, C. Eddy, K. Evans, and Huang, J., “Deactivation of Bacillus Spores in Liquid Desiccant Media”, Unpublished Results, NREL, 2003. 10...Activated Technology RD&D over the past several years. This research develops heating, ventilation, and air-conditioning ( HVAC ) equipment whose...without expensive overcool and reheat. Packaged, solid desiccant dehumidifiers are used extensively in commercial HVAC applications where humidity

  2. Inhibition of forkhead boxO-specific transcription prevents mechanical ventilation-induced diaphragm dysfunction.

    PubMed

    Smuder, Ashley J; Sollanek, Kurt J; Min, Kisuk; Nelson, W Bradley; Powers, Scott K

    2015-05-01

    Mechanical ventilation is a lifesaving measure for patients with respiratory failure. However, prolonged mechanical ventilation results in diaphragm weakness, which contributes to problems in weaning from the ventilator. Therefore, identifying the signaling pathways responsible for mechanical ventilation-induced diaphragm weakness is essential to developing effective countermeasures to combat this important problem. In this regard, the forkhead boxO family of transcription factors is activated in the diaphragm during mechanical ventilation, and forkhead boxO-specific transcription can lead to enhanced proteolysis and muscle protein breakdown. Currently, the role that forkhead boxO activation plays in the development of mechanical ventilation-induced diaphragm weakness remains unknown. This study tested the hypothesis that mechanical ventilation-induced increases in forkhead boxO signaling contribute to ventilator-induced diaphragm weakness. University research laboratory. Young adult female Sprague-Dawley rats. Cause and effect was determined by inhibiting the activation of forkhead boxO in the rat diaphragm through the use of a dominant-negative forkhead boxO adeno-associated virus vector delivered directly to the diaphragm. Our results demonstrate that prolonged (12 hr) mechanical ventilation results in a significant decrease in both diaphragm muscle fiber size and diaphragm-specific force production. However, mechanically ventilated animals treated with dominant-negative forkhead boxO showed a significant attenuation of both diaphragm atrophy and contractile dysfunction. In addition, inhibiting forkhead boxO transcription attenuated the mechanical ventilation-induced activation of the ubiquitin-proteasome system, the autophagy/lysosomal system, and caspase-3. Forkhead boxO is necessary for the activation of key proteolytic systems essential for mechanical ventilation-induced diaphragm atrophy and contractile dysfunction. Collectively, these results suggest that targeting forkhead boxO transcription could be a key therapeutic target to combat ventilator-induced diaphragm dysfunction.

  3. Energy-Efficient Management of Mechanical Ventilation and Relative Humidity in Hot-Humid Climates

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Withers, Jr., Charles R.

    2016-12-01

    In hot and humid climates, it is challenging to energy-efficiently maintain indoor RH at acceptable levels while simultaneously providing required ventilation, particularly in high performance low cooling load homes. The fundamental problem with solely relying on fixed capacity central cooling systems to manage moisture during low sensible load periods is that they are oversized for cooler periods of the year despite being 'properly sized' for a very hot design cooling day. The primary goals of this project were to determine the impact of supplementing a central space conditioning system with 1) a supplemental dehumidifier and 2) a ductless mini-split onmore » seasonal energy use and summer peak power use as well as the impact on thermal distribution and humidity control inside a completely furnished lab home that was continuously ventilated in accordance with ASHRAE 62.2-2013.« less

  4. Building America Case Study: Energy Efficient Management of Mechanical Ventilation and Relative Humidity in Hot-Humid Climates, Cocoa, Florida

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    2017-01-01

    In hot and humid climates, it is challenging to energy-efficiently maintain indoor RH at acceptable levels while simultaneously providing required ventilation, particularly in high performance low cooling load homes. The fundamental problem with solely relying on fixed capacity central cooling systems to manage moisture during low sensible load periods is that they are oversized for cooler periods of the year despite being 'properly sized' for a very hot design cooling day. The primary goals of this project were to determine the impact of supplementing a central space conditioning system with 1) a supplemental dehumidifier and 2) a ductless mini-split onmore » seasonal energy use and summer peak power use as well as the impact on thermal distribution and humidity control inside a completely furnished lab home that was continuously ventilated in accordance with ASHRAE 62.2-2013.« less

  5. Low-Flow Liquid Desiccant Air Conditioning: General Guidance and Site Considerations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kozubal, E.; Herrmann, L.; Deru, M.

    2014-09-01

    Dehumidification or latent cooling in buildings is an area of growing interest that has been identified as needing more research and improved technologies for higher performance. Heating, ventilating, and air-conditioning (HVAC) systems typically expend excessive energy by using overcool-and-reheat strategies to dehumidify buildings. These systems first overcool ventilation air to remove moisture and then reheat the air to meet comfort requirements. Another common strategy incorporates solid desiccant rotors that remove moisture from the air more efficiently; however, these systems increase fan energy consumption because of the high airside pressure drop of solid desiccant rotors and can add heat of absorptionmore » to the ventilation air. Alternatively, liquid desiccant air-conditioning (LDAC) technology provides an innovative dehumidification solution that: (1) eliminates the need for overcooling and reheating from traditional cooling systems; and (2) avoids the increased fan energy and air heating from solid desiccant rotor systems.« less

  6. Evaluation of Humidity Control Options in Hot-Humid Climate Homes (Fact Sheet)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Not Available

    2011-12-01

    This technical highlight describes NREL research to analyze the indoor relative humidity in three home types in the hot-humid climate zone, and examine the impacts of various dehumidification equipment and controls. As the Building America program researches construction of homes that achieve greater source energy savings over typical mid-1990s construction, proper modeling of whole-house latent loads and operation of humidity control equipment has become a high priority. Long-term high relative humidity can cause health and durability problems in homes, particularly in a hot-humid climate. In this study, researchers at the National Renewable Energy Laboratory (NREL) used the latest EnergyPlus toolmore » equipped with the moisture capacitance model to analyze the indoor relative humidity in three home types: a Building America high-performance home; a mid-1990s reference home; and a 2006 International Energy Conservation Code (IECC)-compliant home in hot-humid climate zones. They examined the impacts of various dehumidification equipment and controls on the high-performance home where the dehumidification equipment energy use can become a much larger portion of whole-house energy consumption. The research included a number of simulated cases: thermostat reset, A/C with energy recovery ventilator, heat exchanger assisted A/C, A/C with condenser reheat, A/C with desiccant wheel dehumidifier, A/C with DX dehumidifier, A/C with energy recovery ventilator, and DX dehumidifier. Space relative humidity, thermal comfort, and whole-house source energy consumption were compared for indoor relative humidity set points of 50%, 55%, and 60%. The study revealed why similar trends of high humidity were observed in all three homes regardless of energy efficiency, and why humidity problems are not necessarily unique in the high-performance home. Thermal comfort analysis indicated that occupants are unlikely to notice indoor humidity problems. The study confirmed that supplemental dehumidification is needed to maintain space relative humidity (RH) below 60% in a hot-humid climate home. Researchers also concluded that while all the active dehumidification options included in the study successfully controlled space relative humidity excursions, the increase in whole-house energy consumption was much more sensitive to the humidity set point than the chosen technology option. In the high-performance home, supplemental dehumidification equipment results in a significant source energy consumption penalty at 50% RH set point (12.6%-22.4%) compared to the consumption at 60% RH set point (1.5%-2.7%). At 50% and 55% RH set points, A/C with desiccant wheel dehumidifier and A/C with ERV and high-efficiency DX dehumidifier stand out as the two cases resulting in the smallest increase of source energy consumption. At an RH set point of 60%, all explicit dehumidification technologies result in similar insignificant increases in source energy consumption and thus are equally competitive.« less

  7. Small Changes Yield Large Results at NIST's Net-Zero Energy Residential Test Facility.

    PubMed

    Fanney, A Hunter; Healy, William; Payne, Vance; Kneifel, Joshua; Ng, Lisa; Dougherty, Brian; Ullah, Tania; Omar, Farhad

    2017-12-01

    The Net-Zero Energy Residential Test Facility (NZERTF) was designed to be approximately 60 % more energy efficient than homes meeting the 2012 International Energy Conservation Code (IECC) requirements. The thermal envelope minimizes heat loss/gain through the use of advanced framing and enhanced insulation. A continuous air/moisture barrier resulted in an air exchange rate of 0.6 air changes per hour at 50 Pa. The home incorporates a vast array of extensively monitored renewable and energy efficient technologies including an air-to-air heat pump system with a dedicated dehumidification cycle; a ducted heat-recovery ventilation system; a whole house dehumidifier; a photovoltaic system; and a solar domestic hot water system. During its first year of operation the NZERTF produced an energy surplus of 1023 kWh. Based on observations during the first year, changes were made to determine if further improvements in energy performance could be obtained. The changes consisted of installing a thermostat that incorporated control logic to minimize the use of auxiliary heat, using a whole house dehumidifier in lieu of the heat pump's dedicated dehumidification cycle, and reducing the ventilation rate to a value that met but did not exceed code requirements. During the second year of operation the NZERTF produced an energy surplus of 2241 kWh. This paper describes the facility, compares the performance data for the two years, and quantifies the energy impact of the weather conditions and operational changes.

  8. Energy and cost associated with ventilating office buildings in a tropical climate.

    PubMed

    Rim, Donghyun; Schiavon, Stefano; Nazaroff, William W

    2015-01-01

    Providing sufficient amounts of outdoor air to occupants is a critical building function for supporting occupant health, well-being and productivity. In tropical climates, high ventilation rates require substantial amounts of energy to cool and dehumidify supply air. This study evaluates the energy consumption and associated cost for thermally conditioning outdoor air provided for building ventilation in tropical climates, considering Singapore as an example locale. We investigated the influence on energy consumption and cost of the following factors: outdoor air temperature and humidity, ventilation rate (L/s per person), indoor air temperature and humidity, air conditioning system coefficient of performance (COP), and cost of electricity. Results show that dehumidification of outdoor air accounts for more than 80% of the energy needed for building ventilation in Singapore's tropical climate. Improved system performance and/or a small increase in the indoor temperature set point would permit relatively large ventilation rates (such as 25 L/s per person) at modest or no cost increment. Overall, even in a thermally demanding tropical climate, the energy cost associated with increasing ventilation rate up to 25 L/s per person is less than 1% of the wages of an office worker in an advanced economy like Singapore's. This result implies that the benefits of increasing outdoor air ventilation rate up to 25 L/s per person--which is suggested to provide for productivity increases, lower sick building syndrome symptom prevalence, and reduced sick leave--can be much larger than the incremental cost of ventilation.

  9. Wii, Kinect, and Move. Heart Rate, Oxygen Consumption, Energy Expenditure, and Ventilation due to Different Physically Active Video Game Systems in College Students.

    PubMed

    Scheer, Krista S; Siebrant, Sarah M; Brown, Gregory A; Shaw, Brandon S; Shaw, Ina

    Nintendo Wii, Sony Playstation Move , and Microsoft XBOX Kinect are home video gaming systems that involve player movement to control on-screen game play. Numerous investigations have demonstrated that playing Wii is moderate physical activity at best, but Move and Kinect have not been as thoroughly investigated. The purpose of this study was to compare heart rate, oxygen consumption, and ventilation while playing the games Wii Boxing, Kinect Boxing, and Move Gladiatorial Combat. Heart rate, oxygen consumption, and ventilation were measured at rest and during a graded exercise test in 10 males and 9 females (19.8 ± 0.33 y, 175.4 ± 2.0 cm, 80.2 ± 7.7 kg,). On another day, in a randomized order, the participants played Wii Boxing, K inect Boxing, and Move Gladiatorial Combat while heart rate, ventilation, and oxygen consumption were measured. There were no differences in heart rate (116.0 ± 18.3 vs. 119.3 ± 17.6 vs. 120.1 ± 17.6 beats/min), oxygen consumption (9.2 ± 3.0 vs. 10.6 ± 2.4 vs. 9.6 ± 2.4 ml/kg/min), or minute ventilation (18.9 ± 5.7 vs. 20.8 ± 8.0 vs. 19.7 ± 6.4 L/min) when playing Wii boxing, Kinect boxing, or Move Gladiatorial Combat (respectively). Playing Nintendo Wii Boxing, XBOX Kinect Boxing, and Sony PlayStation Move Gladiatorial Combat all increase heart rate, oxygen consumption, and ventilation above resting levels but there were no significant differences between gaming systems. Overall, playing a "physically active" home video game system does not meet the minimal threshold for moderate intensity physical activity, regardless of gaming system.

  10. Wii, Kinect, and Move. Heart Rate, Oxygen Consumption, Energy Expenditure, and Ventilation due to Different Physically Active Video Game Systems in College Students

    PubMed Central

    SCHEER, KRISTA S.; SIEBRANT, SARAH M.; BROWN, GREGORY A.; SHAW, BRANDON S.; SHAW, INA

    2014-01-01

    Nintendo Wii, Sony Playstation Move, and Microsoft XBOX Kinect are home video gaming systems that involve player movement to control on-screen game play. Numerous investigations have demonstrated that playing Wii is moderate physical activity at best, but Move and Kinect have not been as thoroughly investigated. The purpose of this study was to compare heart rate, oxygen consumption, and ventilation while playing the games Wii Boxing, Kinect Boxing, and Move Gladiatorial Combat. Heart rate, oxygen consumption, and ventilation were measured at rest and during a graded exercise test in 10 males and 9 females (19.8 ± 0.33 y, 175.4 ± 2.0 cm, 80.2 ± 7.7 kg,). On another day, in a randomized order, the participants played Wii Boxing, Kinect Boxing, and Move Gladiatorial Combat while heart rate, ventilation, and oxygen consumption were measured. There were no differences in heart rate (116.0 ± 18.3 vs. 119.3 ± 17.6 vs. 120.1 ± 17.6 beats/min), oxygen consumption (9.2 ± 3.0 vs. 10.6 ± 2.4 vs. 9.6 ± 2.4 ml/kg/min), or minute ventilation (18.9 ± 5.7 vs. 20.8 ± 8.0 vs. 19.7 ± 6.4 L/min) when playing Wii boxing, Kinect boxing, or Move Gladiatorial Combat (respectively). Playing Nintendo Wii Boxing, XBOX Kinect Boxing, and Sony PlayStation Move Gladiatorial Combat all increase heart rate, oxygen consumption, and ventilation above resting levels but there were no significant differences between gaming systems. Overall, playing a “physically active” home video game system does not meet the minimal threshold for moderate intensity physical activity, regardless of gaming system. PMID:27182399

  11. 78 FR 62488 - Energy Conservation Program: Compliance Date for the Dehumidifier Test Procedure

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-22

    ... Conservation Program: Compliance Date for the Dehumidifier Test Procedure AGENCY: Office of Energy Efficiency.... Department of Energy (DOE) proposes to revise the compliance date for the dehumidifier test procedures... manufacturers to test using only the active mode provisions in the test procedure for dehumidifiers currently...

  12. The Multiple Inert Gas Elimination Technique: A User’s Manual

    DTIC Science & Technology

    2016-02-11

    These quantities are measured for inspired and expired oxygen and carbon dioxide, as well as minute ventilation . Expired Gas Sampling...Schematic of Ventilator /MIGET Sampling Circuit” (pp 28-30). By this mode, the ventilator is effectively , completely excluded from the sampling apparatus...connects the subject to the mixing box and the exhaust from the mixing box to the ventilator , temperature control is of the highest priority. The tubing

  13. Energy and Cost Associated with Ventilating Office Buildings in a Tropical Climate

    PubMed Central

    Rim, Donghyun; Schiavon, Stefano; Nazaroff, William W.

    2015-01-01

    Providing sufficient amounts of outdoor air to occupants is a critical building function for supporting occupant health, well-being and productivity. In tropical climates, high ventilation rates require substantial amounts of energy to cool and dehumidify supply air. This study evaluates the energy consumption and associated cost for thermally conditioning outdoor air provided for building ventilation in tropical climates, considering Singapore as an example locale. We investigated the influence on energy consumption and cost of the following factors: outdoor air temperature and humidity, ventilation rate (L/s per person), indoor air temperature and humidity, air conditioning system coefficient of performance (COP), and cost of electricity. Results show that dehumidification of outdoor air accounts for more than 80% of the energy needed for building ventilation in Singapore’s tropical climate. Improved system performance and/or a small increase in the indoor temperature set point would permit relatively large ventilation rates (such as 25 L/s per person) at modest or no cost increment. Overall, even in a thermally demanding tropical climate, the energy cost associated with increasing ventilation rate up to 25 L/s per person is less than 1% of the wages of an office worker in an advanced economy like Singapore’s. This result implies that the benefits of increasing outdoor air ventilation rate up to 25 L/s per person — which is suggested to provide for productivity increases, lower sick building syndrome symptom prevalence, and reduced sick leave — can be much larger than the incremental cost of ventilation. PMID:25822504

  14. 40 CFR 63.8243 - What equations and procedures must I use to demonstrate continuous compliance?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... hydrogen streams and end box ventilation system vents. For each consecutive 52-week period, you must determine the g Hg/Mg Cl2 produced from all by-product hydrogen streams and all end box ventilation system... weekly mercury emission rate in grams per week for each by-product hydrogen stream and for each end box...

  15. LiCl Dehumidifier LiBr absorption chiller hybrid air conditioning system with energy recovery

    DOEpatents

    Ko, Suk M.

    1980-01-01

    This invention relates to a hybrid air conditioning system that combines a solar powered LiCl dehumidifier with a LiBr absorption chiller. The desiccant dehumidifier removes the latent load by absorbing moisture from the air, and the sensible load is removed by the absorption chiller. The desiccant dehumidifier is coupled to a regenerator and the desiccant in the regenerator is heated by solar heated hot water to drive the moisture therefrom before being fed back to the dehumidifier. The heat of vaporization expended in the desiccant regenerator is recovered and used to partially preheat the driving fluid of the absorption chiller, thus substantially improving the overall COP of the hybrid system.

  16. 10 CFR Appendix X1 to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Dehumidifiers

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    .... 2.4 Energy factor for dehumidifiers means a measure of energy efficiency of a dehumidifier... batteries and the determination, classification, and testing of relevant modes. 3.2.2 Electrical energy...

  17. Energy saving effect of desiccant ventilation system using Wakkanai siliceous shale

    NASA Astrophysics Data System (ADS)

    Nabeshima, Yuki; Togawa, Jun-ya; Nagano, Katsunori; Kazuyo, Tsuzuki

    2017-10-01

    The nuclear power station accident resulting from the Great East Japan Earthquake disaster has resulted in a constrained electricity supply. However, in this Asian region there is high temperature and high humidity and consequently dehumidification process requires a huge amount of energy. This is the reason for the increasing energy consumption in the residential and commercial sectors. Accordingly, a high efficiency air-conditioning system is needed to be developed. The desiccant ventilation system is effective to reduce energy consumption for the dehumidification process. This system is capable of dehumidifying without dew condensing unlike a conventional air-conditioning system. Then we focused on Wakkanai Siliceous Shale (WSS) as a desiccant material to develop a new desiccant ventilation system. This is low priced, high performance, new type of thing. The aim of this study is to develop a desiccant ventilation unit using the WSS rotor which can be regenerated with low-temperature by numerical calculation. The results of performance prediction of the desiccant unit, indicate that it is possible to regenerate the WSS rotor at low-temperature of between 35 - 45 °C. In addition, we produced an actual measurement for the desiccant unit and air-conditioning unit. This air-conditioning system was capable to reduce roughly 40 % of input energy consumption.

  18. A simple analytical method to estimate all exit parameters of a cross-flow air dehumidifier using liquid desiccant.

    PubMed

    Bassuoni, M M

    2014-03-01

    The dehumidifier is a key component in liquid desiccant air-conditioning systems. Analytical solutions have more advantages than numerical solutions in studying the dehumidifier performance parameters. This paper presents the performance results of exit parameters from an analytical model of an adiabatic cross-flow liquid desiccant air dehumidifier. Calcium chloride is used as desiccant material in this investigation. A program performing the analytical solution is developed using the engineering equation solver software. Good accuracy has been found between analytical solution and reliable experimental results with a maximum deviation of +6.63% and -5.65% in the moisture removal rate. The method developed here can be used in the quick prediction of the dehumidifier performance. The exit parameters from the dehumidifier are evaluated under the effects of variables such as air temperature and humidity, desiccant temperature and concentration, and air to desiccant flow rates. The results show that hot humid air and desiccant concentration have the greatest impact on the performance of the dehumidifier. The moisture removal rate is decreased with increasing both air inlet temperature and desiccant temperature while increases with increasing air to solution mass ratio, inlet desiccant concentration, and inlet air humidity ratio.

  19. 10 CFR Appendix X1 to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Dehumidifiers

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    .... 2.4Energy factor for dehumidifiers means a measure of energy efficiency of a dehumidifier calculated... batteries and the determination, classification, and testing of relevant modes. 3.2.2Electrical energy...

  20. Development of Smart Ventilation Control Algorithms for Humidity Control in High-Performance Homes in Humid U.S. Climates

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Less, Brennan; Walker, Iain; Ticci, Sara

    Past field research and simulation studies have shown that high performance homes experience elevated indoor humidity levels for substantial portions of the year in humid climates. This is largely the result of lower sensible cooling loads, which reduces the moisture removed by the cooling system. These elevated humidity levels lead to concerns about occupant comfort, health and building durability. Use of mechanical ventilation at rates specified in ASHRAE Standard 62.2-2013 are often cited as an additional contributor to humidity problems in these homes. Past research has explored solutions, including supplemental dehumidification, cooling system operational enhancements and ventilation system design (e.g.,more » ERV, supply, exhaust, etc.). This project’s goal is to develop and demonstrate (through simulations) smart ventilation strategies that can contribute to humidity control in high performance homes. These strategies must maintain IAQ via equivalence with ASHRAE Standard 62.2-2013. To be acceptable they must not result in excessive energy use. Smart controls will be compared with dehumidifier energy and moisture performance. This work explores the development and performance of smart algorithms for control of mechanical ventilation systems, with the objective of reducing high humidity in modern high performance residences. Simulations of DOE Zero-Energy Ready homes were performed using the REGCAP simulation tool. Control strategies were developed and tested using the Residential Integrated Ventilation (RIVEC) controller, which tracks pollutant exposure in real-time and controls ventilation to provide an equivalent exposure on an annual basis to homes meeting ASHRAE 62.2-2013. RIVEC is used to increase or decrease the real-time ventilation rate to reduce moisture transport into the home or increase moisture removal. This approach was implemented for no-, one- and two-sensor strategies, paired with a variety of control approaches in six humid climates (Miami, Orlando, Houston, Charleston, Memphis and Baltimore). The control options were compared to a baseline system that supplies outdoor air to a central forced air cooling (and heating) system (CFIS) that is often used in hot humid climates. Simulations were performed with CFIS ventilation systems operating on a 33% duty-cycle, consistent with 62.2-2013. The CFIS outside airflow rates were set to 0%, 50% and 100% of 62.2-2013 requirements to explore effects of ventilation rate on indoor high humidity. These simulations were performed with and without a dehumidifier in the model. Ten control algorithms were developed and tested. Analysis of outdoor humidity patterns facilitated smart control development. It was found that outdoor humidity varies most strongly seasonally—by month of the year—and that all locations follow the similar pattern of much higher humidity during summer. Daily and hourly variations in outdoor humidity were found to be progressively smaller than the monthly seasonal variation. Patterns in hourly humidity are driven by diurnal daily patterns, so they were predictable but small, and were unlikely to provide much control benefit. Variation in outdoor humidity between days was larger, but unpredictable, except by much more complex climate models. We determined that no-sensor strategies might be able to take advantage of seasonal patterns in humidity, but that real-time smart controls were required to capture variation between days. Sensor-based approaches are also required to respond dynamically to indoor conditions and variations not considered in our analysis. All smart controls face trade-offs between sensor accuracy, cost, complexity and robustness.« less

  1. Performance assessment of radiant cooling system integrated with desiccant assisted DOAS with solar regeneration

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Khan, Yasin; Singh, Gaurav; Mathur, Jyotirmay

    The Radiant cooling system integrated with Dedicated Outdoor Air System (DOAS) is a viable substitution for conventional all air system in order to reduce primary energy consumption, as it decouples the cooling and ventilation task. In DOAS major portion of energy is consumed in cooling coil where it dehumidifies the process supply air. This study describes an alternate solution for dehumidification, with the substitution of the desiccant wheel with solar regeneration in place of a chilled water coil based dehumidifier. In this paper, simulations were carried out using EnergyPlus on a reference medium office building to investigate the contribution ofmore » solar energy towards the total energy consumption of desiccant assisted DOAS with radiant cooling system. To evaluate the system performance and energy saving potential, desiccant based DOAS is compared with cooling coil assisted DOAS integrated with Radiant cooling system. Simulations were carried out for different solar collector area to evaluate primary energy savings. Results indicate that from 7.4 % to 28.6 % energy saving (according to different collector area) can be achieved due to the solar regeneration in desiccant assisted DOAS, the impact of different solar collector area on potential of energy savings is also described.« less

  2. Performance assessment of radiant cooling system integrated with desiccant assisted DOAS with solar regeneration

    DOE PAGES

    Khan, Yasin; Singh, Gaurav; Mathur, Jyotirmay; ...

    2017-06-13

    The Radiant cooling system integrated with Dedicated Outdoor Air System (DOAS) is a viable substitution for conventional all air system in order to reduce primary energy consumption, as it decouples the cooling and ventilation task. In DOAS major portion of energy is consumed in cooling coil where it dehumidifies the process supply air. This study describes an alternate solution for dehumidification, with the substitution of the desiccant wheel with solar regeneration in place of a chilled water coil based dehumidifier. In this paper, simulations were carried out using EnergyPlus on a reference medium office building to investigate the contribution ofmore » solar energy towards the total energy consumption of desiccant assisted DOAS with radiant cooling system. To evaluate the system performance and energy saving potential, desiccant based DOAS is compared with cooling coil assisted DOAS integrated with Radiant cooling system. Simulations were carried out for different solar collector area to evaluate primary energy savings. Results indicate that from 7.4 % to 28.6 % energy saving (according to different collector area) can be achieved due to the solar regeneration in desiccant assisted DOAS, the impact of different solar collector area on potential of energy savings is also described.« less

  3. 78 FR 21215 - Energy Conservation Program for Consumer Products: Association of Home Appliance Manufacturers...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-10

    ... to amend the test procedures for residential dishwashers, dehumidifiers, and conventional cooking... procedures for residential dishwashers, dehumidifiers, and conventional cooking products, go to the Federal e..., dehumidifiers, and conventional cooking products (77 FR 65942, Oct. 31, 2012) and its direct final rule to amend...

  4. A simple analytical method to estimate all exit parameters of a cross-flow air dehumidifier using liquid desiccant

    PubMed Central

    Bassuoni, M.M.

    2013-01-01

    The dehumidifier is a key component in liquid desiccant air-conditioning systems. Analytical solutions have more advantages than numerical solutions in studying the dehumidifier performance parameters. This paper presents the performance results of exit parameters from an analytical model of an adiabatic cross-flow liquid desiccant air dehumidifier. Calcium chloride is used as desiccant material in this investigation. A program performing the analytical solution is developed using the engineering equation solver software. Good accuracy has been found between analytical solution and reliable experimental results with a maximum deviation of +6.63% and −5.65% in the moisture removal rate. The method developed here can be used in the quick prediction of the dehumidifier performance. The exit parameters from the dehumidifier are evaluated under the effects of variables such as air temperature and humidity, desiccant temperature and concentration, and air to desiccant flow rates. The results show that hot humid air and desiccant concentration have the greatest impact on the performance of the dehumidifier. The moisture removal rate is decreased with increasing both air inlet temperature and desiccant temperature while increases with increasing air to solution mass ratio, inlet desiccant concentration, and inlet air humidity ratio. PMID:25685485

  5. 40 CFR 63.8246 - How do I demonstrate continuous compliance with the emission limitations and work practice...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Continuous Compliance... practice standards? (a) By-product hydrogen streams and end box ventilation system vents. (1) For all by-product hydrogen streams and all end box ventilation system vents, if applicable, you must demonstrate...

  6. 40 CFR 63.8246 - How do I demonstrate continuous compliance with the emission limitations and work practice...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Continuous Compliance... practice standards? (a) By-product hydrogen streams and end box ventilation system vents. (1) For all by-product hydrogen streams and all end box ventilation system vents, if applicable, you must demonstrate...

  7. 40 CFR 63.8246 - How do I demonstrate continuous compliance with the emission limitations and work practice...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Continuous Compliance... practice standards? (a) By-product hydrogen streams and end box ventilation system vents. (1) For all by-product hydrogen streams and all end box ventilation system vents, if applicable, you must demonstrate...

  8. 40 CFR 63.8246 - How do I demonstrate continuous compliance with the emission limitations and work practice...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Continuous Compliance... practice standards? (a) By-product hydrogen streams and end box ventilation system vents. (1) For all by-product hydrogen streams and all end box ventilation system vents, if applicable, you must demonstrate...

  9. 40 CFR 63.8246 - How do I demonstrate continuous compliance with the emission limitations and work practice...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Continuous Compliance... practice standards? (a) By-product hydrogen streams and end box ventilation system vents. (1) For all by-product hydrogen streams and all end box ventilation system vents, if applicable, you must demonstrate...

  10. 40 CFR 63.8243 - What equations and procedures must I use to demonstrate continuous compliance?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Continuous Compliance Requirements § 63... hydrogen streams and end box ventilation system vents. For each consecutive 52-week period, you must determine the g Hg/Mg Cl2 produced from all by-product hydrogen streams and all end box ventilation system...

  11. 40 CFR 63.8243 - What equations and procedures must I use to demonstrate continuous compliance?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Continuous Compliance Requirements § 63... hydrogen streams and end box ventilation system vents. For each consecutive 52-week period, you must determine the g Hg/Mg Cl2 produced from all by-product hydrogen streams and all end box ventilation system...

  12. 40 CFR 63.8243 - What equations and procedures must I use to demonstrate continuous compliance?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Continuous Compliance Requirements § 63... hydrogen streams and end box ventilation system vents. For each consecutive 52-week period, you must determine the g Hg/Mg Cl2 produced from all by-product hydrogen streams and all end box ventilation system...

  13. Water-heating dehumidifier

    DOEpatents

    Tomlinson, John J.

    2006-04-18

    A water-heating dehumidifier includes a refrigerant loop including a compressor, at least one condenser, an expansion device and an evaporator including an evaporator fan. The condenser includes a water inlet and a water outlet for flowing water therethrough or proximate thereto, or is affixed to the tank or immersed into the tank to effect water heating without flowing water. The immersed condenser design includes a self-insulated capillary tube expansion device for simplicity and high efficiency. In a water heating mode air is drawn by the evaporator fan across the evaporator to produce cooled and dehumidified air and heat taken from the air is absorbed by the refrigerant at the evaporator and is pumped to the condenser, where water is heated. When the tank of water heater is full of hot water or a humidistat set point is reached, the water-heating dehumidifier can switch to run as a dehumidifier.

  14. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111.15-10 Ventilation. (a) General. Each room, locker, and box for storage batteries must be arranged or ventilated to prevent... with the battery charger so that the battery cannot be charged without ventilation. (c) Large battery...

  15. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111.15-10 Ventilation. (a) General. Each room, locker, and box for storage batteries must be arranged or ventilated to prevent... with the battery charger so that the battery cannot be charged without ventilation. (c) Large battery...

  16. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111.15-10 Ventilation. (a) General. Each room, locker, and box for storage batteries must be arranged or ventilated to prevent... with the battery charger so that the battery cannot be charged without ventilation. (c) Large battery...

  17. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111.15-10 Ventilation. (a) General. Each room, locker, and box for storage batteries must be arranged or ventilated to prevent... with the battery charger so that the battery cannot be charged without ventilation. (c) Large battery...

  18. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111.15-10 Ventilation. (a) General. Each room, locker, and box for storage batteries must be arranged or ventilated to prevent... with the battery charger so that the battery cannot be charged without ventilation. (c) Large battery...

  19. Selecting HVAC Systems to Achieve Comfortable and Cost-effective Residential Net-Zero Energy Buildings.

    PubMed

    Wu, Wei; Skye, Harrison M; Domanski, Piotr A

    2018-02-15

    HVAC is responsible for the largest share of energy use in residential buildings and plays an important role in broader implementation of net-zero energy building (NZEB). This study investigated the energy, comfort and economic performance of commercially-available HVAC technologies for a residential NZEB. An experimentally-validated model was used to evaluate ventilation, dehumidification, and heat pump options for the NZEB in the mixed-humid climate zone. Ventilation options were compared to mechanical ventilation without recovery; a heat recovery ventilator (HRV) and energy recovery ventilator (ERV) respectively reduced the HVAC energy by 13.5 % and 17.4 % and reduced the building energy by 7.5 % and 9.7 %. There was no significant difference in thermal comfort between the ventilation options. Dehumidification options were compared to an air-source heat pump (ASHP) with a separate dehumidifier; the ASHP with dedicated dehumidification reduced the HVAC energy by 7.3 % and the building energy by 3.9 %. The ASHP-only option (without dedicated dehumidification) reduced the initial investment but provided the worst comfort due to high humidity levels. Finally, ground-source heat pump (GSHP) alternatives were compared to the ASHP; the GSHP with two and three boreholes reduced the HVAC energy by 26.0 % and 29.2 % and the building energy by 13.1 % and 14.7 %. The economics of each HVAC configuration was analyzed using installation cost data and two electricity price structures. The GSHPs with the ERV and dedicated dehumidification provided the highest energy savings and good comfort, but were the most expensive. The ASHP with dedicated dehumidification and the ERV (or HRV) provided reasonable payback periods.

  20. Annual verifications--a tick-box exercise?

    PubMed

    Walker, Gwen; Williams, David

    2014-09-01

    With the onus on healthcare providers and their staff to protect patients against all elements of 'avoidable harm' perhaps never greater, Gwen Walker, a highly experienced infection prevention control nurse specialist, and David Williams, MD of Approved Air, who has 30 years' experience in validation and verification of ventilation and ultraclean ventilation systems, examine changing requirements for, and trends in, operating theatre ventilation. Validation and verification reporting on such vital HVAC equipment should not, they argue, merely be viewed as a 'tick-box exercise'; it should instead 'comprehensively inform key stakeholders, and ultimately form part of clinical governance, thus protecting those ultimately named responsible for organisation-wide safety at Trust board level'.

  1. 77 FR 70105 - Energy Conservation Program: Test Procedures for Residential Dishwashers, Dehumidifiers, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-23

    ... Conservation Program: Test Procedures for Residential Dishwashers, Dehumidifiers, and Conventional Cooking... conventional cooking products under the Energy Policy and Conservation Act. DATES: The effective date of this...

  2. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gao, Zhiming; Abdelaziz, Omar; Qu, Ming

    This paper introduces a first-order physics-based model that accounts for the fundamental heat and mass transfer between a humid-air vapor stream on feed side to another flow stream on permeate side. The model comprises a few optional submodels for membrane mass transport; and it adopts a segment-by-segment method for discretizing heat and mass transfer governing equations for flow streams on feed and permeate sides. The model is able to simulate both dehumidifiers and energy recovery ventilators in parallel-flow, cross-flow, and counter-flow configurations. The predicted tresults are compared reasonably well with the measurements. The open-source codes are written in C++. Themore » model and open-source codes are expected to become a fundament tool for the analysis of membrane-based dehumidification in the future.« less

  3. [Anesthesia ventilators].

    PubMed

    Otteni, J C; Beydon, L; Cazalaà, J B; Feiss, P; Nivoche, Y

    1997-01-01

    To review anaesthesia ventilators in current use in France by categories of ventilators. References were obtained from computerized bibliographic search. (Medline), recent review articles, the library of the service and personal files. Anaesthesia ventilators can be allocated into three groups, depending on whether they readminister expired gases or not or allow both modalities. Contemporary ventilators provide either constant volume ventilation, or constant pressure ventilation, with or without a pressure plateau. Ventilators readministering expired gases after CO2 absorption, or closed circuit ventilators, are either of a double- or a single-circuit design. Double-circuit ventilators, or pneumatical bag or bellows squeezers, or bag-in-bottle or bellows-in-bottle (or box) ventilators, consist of a primary, or driving circuit (bottle or box) and a secondary or patient circuit (including a bag or a bellows or membrane chambers). Bellows-in-bottle ventilators have either standing bellows ascending at expiration, or hanging bellows, descending at expiration. Ascending bellows require a positive pressure of about 2 cmH2O throughout exhalation to allow the bellows to refill. The expired gas volume is a valuable indicator for leak and disconnection. Descending bellows generate a slight negative pressure during exhalation. In case of leak or disconnection they aspirate ambient air and cannot act therefore as an indicator for integrity of the circuit and the patient connection. Closed circuit ventilators with a single-circuit (patient circuit) include a insufflating device consisting either in a bellows or a cylinder with a piston, operated by a electric or pneumatic motor. As the hanging bellows of the double circuit ventilators, they generate a slight negative pressure during exhalation and aspirate ambient air in case of leak or disconnection. Ventilators not designed for the readministration of expired gases, or open circuit ventilators, are generally stand-alone mechanical ventilators modified to allow the administration of inhalational anaesthetic agents.

  4. Theoretical modelling and optimization of bubble column dehumidifier for a solar driven humidification-dehumidification system

    NASA Astrophysics Data System (ADS)

    Ranjitha, P. Raj; Ratheesh, R.; Jayakumar, J. S.; Balakrishnan, Shankar

    2018-02-01

    Availability and utilization of energy and water are the top most global challenges being faced by the new millennium. At the present state water scarcity has become a global as well as a regional challenge. 40 % of world population faces water shortage. Challenge of water scarcity can be tackled only with increase in water supply beyond what is obtained from hydrological cycle. This can be achieved either by desalinating the sea water or by reusing the waste water. High energy requirement need to be overcome for either of the two processes. Of many desalination technologies, humidification dehumidification (HDH) technology powered by solar energy is widely accepted for small scale production. Detailed optimization studies on system have the potential to effectively utilize the solar energy for brackish water desalination. Dehumidification technology, specifically, require further study because the dehumidifier effectiveness control the energetic performance of the entire HDH system. The reason attributes to the high resistance involved to diffuse dilute vapor through air in a dehumidifier. The present work intends to optimize the design of a bubble column dehumidifier for a solar energy driven desalination process. Optimization is carried out using Matlab simulation. Design process will identify the unique needs of a bubble column dehumidifier in HDH system.

  5. Experimental study of hybrid interface cooling system using air ventilation and nanofluid

    NASA Astrophysics Data System (ADS)

    Rani, M. F. H.; Razlan, Z. M.; Bakar, S. A.; Desa, H.; Wan, W. K.; Ibrahim, I.; Kamarrudin, N. S.; Bin-Abdun, Nazih A.

    2017-09-01

    The hybrid interface cooling system needs to be established to chill the battery compartment of electric car and maintained its ambient temperature inside the compartment between 25°C to 35°C. The air cooling experiment has been conducted to verify the cooling capacity, compressor displacement volume, dehumidifying value and mass flow rate of refrigerant (R-410A). At the same time, liquid cooling system is analysed theoretically by comparing the performance of two types of nanofluid, i.e., CuO + Water and Al2O3 + Water, based on the heat load generated inside the compartment. In order for the result obtained to be valid and reliable, several assumptions are considered during the experimental and theoretical analysis. Results show that the efficiency of the hybrid interface cooling system is improved as compared to the individual cooling system.

  6. 77 FR 49739 - Energy Conservation Standards for Residential Dehumidifiers: Public Meeting and Availability of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-17

    ... dehumidifiers. DOE also encourages written comments on potential amended standards, including comments on the... INFORMATION: I. Introduction and Legal Authority II. Test Procedures III. Energy Conservation Standards I... standard on the manufacturers and consumers of the affected products; (2) The savings in operating costs...

  7. 58. View of high pressure IngersollRand dehumidifier/dessicator and compressor system ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    58. View of high pressure Ingersoll-Rand dehumidifier/dessicator and compressor system to supply dry pressurized air to waveguides. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

  8. Performance of the SERI parallel-passage dehumidifer

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Schlepp, D.; Barlow, R.

    1984-09-01

    The key component in improving the performance of solar desiccant cooling systems is the dehumidifier. A parallel-passage geometry for the desiccant dehumidifier has been identified as meeting key criteria of low pressure drop, high mass transfer efficiency, and compact size. An experimental program to build and test a small-scale prototype of this design was undertaken in FY 1982, and the results are presented in this report. Computer models to predict the adsorption/desorption behavior of desiccant dehumidifiers were updated to take into account the geometry of the bed and predict potential system performance using the new component design. The parallel-passage designmore » proved to have high mass transfer effectiveness and low pressure drop over a wide range of test conditions typical of desiccant cooling system operation. The prototype dehumidifier averaged 93% effectiveness at pressure drops of less than 50 Pa at design point conditions. Predictions of system performance using models validated with the experimental data indicate that system thermal coefficients of performance (COPs) of 1.0 to 1.2 and electrical COPs above 8.5 are possible using this design.« less

  9. Particle transport in low-energy ventilation systems. Part 2: Transients and experiments.

    PubMed

    Bolster, D T; Linden, P F

    2009-04-01

    Providing adequate indoor air quality while reducing energy consumption is a must for efficient ventilation system design. In this work, we study the transport of particulate contaminants in a displacement-ventilated space, using the idealized 'emptying filling box' model (P.F. Linden, G.F. Lane-serff and D.A. Smeed (1990) Emptying filling boxes: the fluid mechanics of natural ventilation, J. fluid Mech., 212, 309-335.). In this paper, we focused on transient contaminant transport by modeling three transient contamination scenarios, namely the so called 'step-up', 'step-down', and point source cases. Using analytical integral models and numerical models we studied the transient behavior of each of these three cases. We found that, on average, traditional and low-energy systems can be similar in overall pollutant removal efficiency, although quite different vertical gradients can exist. This plays an important role in estimating occupant exposure to contaminant. A series of laboratory experiments were conducted to validate the developed models. The results presented here illustrate that the source location plays a very important role in the distribution of contaminant concentration for spaces ventilated by low energy displacement-ventilation systems. With these results and the knowledge of typical contaminant sources for a given type of space practitioners can design or select more effective systems for the purpose at hand.

  10. 10 CFR Appendix X to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Dehumidifiers

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... of Dehumidifiers X Appendix X to Subpart B of Part 430 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY CONSERVATION PROGRAM FOR CONSUMER PRODUCTS Test Procedures Pt. 430, Subpt. B, App. X Appendix X to Subpart B of Part 430—Uniform Test Method for Measuring the Energy Consumption of...

  11. 10 CFR Appendix X to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Dehumidifiers

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... of Dehumidifiers X Appendix X to Subpart B of Part 430 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY CONSERVATION PROGRAM FOR CONSUMER PRODUCTS Test Procedures Pt. 430, Subpt. B, App. X Appendix X to Subpart B of Part 430—Uniform Test Method for Measuring the Energy Consumption of...

  12. 10 CFR Appendix X to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Dehumidifiers

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... of Dehumidifiers X Appendix X to Subpart B of Part 430 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY CONSERVATION PROGRAM FOR CONSUMER PRODUCTS Test Procedures Pt. 430, Subpt. B, App. X Appendix X to Subpart B of Part 430—Uniform Test Method for Measuring the Energy Consumption of...

  13. 10 CFR Appendix X to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Dehumidifiers

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... of Dehumidifiers X Appendix X to Subpart B of Part 430 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY CONSERVATION PROGRAM FOR CONSUMER PRODUCTS Test Procedures Pt. 430, Subpt. B, App. X Appendix X to Subpart B of Part 430—Uniform Test Method for Measuring the Energy Consumption of...

  14. 10 CFR Appendix X to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Dehumidifiers

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... of Dehumidifiers X Appendix X to Subpart B of Part 430 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY CONSERVATION PROGRAM FOR CONSUMER PRODUCTS Test Procedures Pt. 430, Subpt. B, App. X Appendix X to Subpart B of Part 430—Uniform Test Method for Measuring the Energy Consumption of...

  15. CONTROL ROOM WITH SPRINKLER SYSTEM CONTROLS, INCLUDING MANUAL CONTROL BOXES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CONTROL ROOM WITH SPRINKLER SYSTEM CONTROLS, INCLUDING MANUAL CONTROL BOXES FOR THE VENTILATION SYSTEM AND A PLC SWITCH FOR AUTOMATIC CO (CARBON MONOXIDE) SYSTEM. THE AIR TESTING SYSTEM IS FREE STANDING AND THE FANS ARE COMPUTER-OPERATED. - Alaskan Way Viaduct and Battery Street Tunnel, Seattle, King County, WA

  16. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Apte, Michael G.; Mendell, Mark J.; Sohn, Michael D.

    Through mass-balance modeling of various ventilation scenarios that might satisfy the ASHRAE 62.1 Indoor Air Quality (IAQ) Procedure, we estimate indoor concentrations of contaminants of concern (COCs) in California “big box” stores, compare estimates to available thresholds, and for selected scenarios estimate differences in energy consumption. Findings are intended to inform decisions on adding performance-based approaches to ventilation rate (VR) standards for commercial buildings. Using multi-zone mass-balance models and available contaminant source rates, we estimated concentrations of 34 COCs for multiple ventilation scenarios: VRmin (0.04 cfm/ft2 ), VRmax (0.24 cfm/ft2 ), and VRmid (0.14 cfm/ft2 ). We compared COC concentrationsmore » with available health, olfactory, and irritant thresholds. We estimated building energy consumption at different VRs using a previously developed EnergyPlus model. VRmax did control all contaminants adequately, but VRmin did not, and VRmid did so only marginally. Air cleaning and local ventilation near strong sources both showed promise. Higher VRs increased indoor concentrations of outdoor air pollutants. Lowering VRs in big box stores in California from VRmax to VRmid would reduce total energy use by an estimated 6.6% and energy costs by 2.5%. Reducing the required VRs in California’s big box stores could reduce energy use and costs, but poses challenges for health and comfort of occupants. Source removal, air cleaning, and local ventilation may be needed at reduced VRs, and even at current recommended VRs. Also, alternative ventilation strategies taking climate and season into account in ventilation schedules may provide greater energy cost savings than constant ventilation rates, while improving IAQ.« less

  17. 77 FR 65941 - Energy Conservation Program: Test Procedures for Residential Dishwashers, Dehumidifiers, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-31

    ...The U.S. Department of Energy (DOE) establishes new test procedures for residential dishwashers and dehumidifiers, and amends the currently applicable test procedure for conventional cooking products under the Energy Policy and Conservation Act. The new test procedures include provisions for measuring standby mode and off mode energy consumption, and update the provisions for measuring active mode energy consumption and, for dishwashers, water consumption. This final rule also amends the certification, compliance, and enforcement requirements for dishwashers, dehumidifiers and conventional cooking products, amends certain provisions in the currently applicable dishwasher test procedure, and eliminates an obsolete energy efficiency metric in the dishwasher test procedure and provisions in the cooking products test procedure that have become obsolete due to the elimination of standing pilot lights.

  18. Technology for noninvasive mechanical ventilation: looking into the black box

    PubMed Central

    Navajas, Daniel; Montserrat, Josep M.

    2016-01-01

    Current devices for providing noninvasive respiratory support contain sensors and built-in intelligence for automatically modifying ventilation according to the patient's needs. These devices, including automatic continuous positive airway pressure devices and noninvasive ventilators, are technologically complex and offer a considerable number of different modes of ventilation and setting options, the details of which are sometimes difficult to capture by the user. Therefore, better predicting and interpreting the actual performance of these ventilation devices in clinical application requires understanding their functioning principles and assessing their performance under well controlled bench test conditions with simulated patients. This concise review presents an updated perspective of the theoretical basis of intelligent continuous positive airway pressure and noninvasive ventilation devices, and of the tools available for assessing how these devices respond under specific ventilation phenotypes in patients requiring breathing support. PMID:27730162

  19. Microwave blanching and drying characteristics of Centella asiatica (L.) urban leaves using tray and heat pump-assisted dehumidified drying.

    PubMed

    Trirattanapikul, W; Phoungchandang, S

    2014-12-01

    The appropriate stage of maturity of Centella asiatica (L.) Urban leaves was investigated. Mature leaves with large diameter contained high total phenolics and % inhibition. Microwave blanching for 30 s retained the highest total phenolics and the microwave blanching for 30 s and 45 s retained the highest % inhibition. Modified Henderson and Modified Chung-Pfost models showed the best fit to both fresh and blanched leaves for equilibrium moisture content, Xe = f(RHe, T) and equilibrium relative humidity, RHe = f(Xe, T), respectively. The Modified Page model was the most effective model in describing the leaf drying. All drying was in the falling rate period. The drying constant was related to drying air temperature using the Arrhenius model. Effective moisture diffusivities increased with increasing temperature and blanching treatments as well as dehumidification by heat pump-assisted dehumidified dryer. The heat pump-assited dehumidified drying incorporated by the microwave blanching could reduce the drying time at 40 °C by 31.2 % and increase % inhibition by 6.1 %. Quality evaluation by total phenolics, % inhibition and rehydration ratio showed the best quality for C. asiatica leaves pretreated by microwave blanching and dried at 40 °C in heat pump-assisted dehumidified dryer.

  20. Status Report on Medical Materiel Items Tested and Evaluated for Use in the USAF Aeromedical Evacuation System.

    DTIC Science & Technology

    1986-06-01

    P.O. Box 2007 3101 E. Alejo Rd. Palm Springs, CA 92262 Telephone: (619) 327-1571 Date Evaluated June 1979 Summary The BABYbird Ventilator, Model 5900...air. Procurement Manufacturer 15 Product and Manufacturer Infant AIRbird Resuscitator Medical Products Oivision/3M P.O. Box 2007 3101 E. Alejo Rd. Palm...Silicone Bag Medical Products Division/3M P.O. Box 20073101 E. Alejo Rd Palm Springs, CA 92262 Telephone: (619) 327-1571 Date Evaluated July 1978 Sumary

  1. Dehumidifying Heat Pipe

    NASA Technical Reports Server (NTRS)

    Khattar, Mukesh K.

    1993-01-01

    U-shaped heat pipe partly dehumidifies air leaving air conditioner. Fits readily in air-handling unit of conditioner. Evaporator and condenser sections of heat pipe consist of finned tubes in comb pattern. Each tube sealed at one end and joined to manifold at other. Sections connected by single pipe carrying vapor to condenser manifold and liquid to evaporator manifold. Simple on/off or proportional valve used to control flow of working fluid. Valve actuated by temperature/humidity sensor.

  2. Desiccant-based dehumidification system and method

    DOEpatents

    Fischer, John C.

    2004-06-22

    The present invention provides an apparatus for dehumidifying air supplied to an enclosed space by an air conditioning unit. The apparatus includes a partition separating the interior of the housing into a supply portion and a regeneration portion. The supply portion has an inlet for receiving supply air from the air conditioning unit and an outlet for supplying air to the enclosed space. A regeneration fan creates the regeneration air stream. The apparatus includes an active desiccant wheel positioned such that a portion of the wheel extends into the supply portion and a portion of the wheel extends into the regeneration portion, so that the wheel can rotate through the supply air stream and the regeneration air stream to dehumidify the supply air stream. A heater warms the regeneration air stream as necessary to regenerate the desiccant wheel. The invention also comprises a hybrid system that combines air conditioning and dehumidifying components into a single integrated unit.

  3. Control methods and systems for indirect evaporative coolers

    DOEpatents

    Woods, Jason; Kozubal, Erik

    2015-09-22

    A control method for operating an indirect evaporative cooler to control temperature and humidity. The method includes operating an airflow control device to provide supply air at a flow rate to a liquid desiccant dehumidifier. The supply air flows through the dehumidifier and an indirect evaporative cooler prior to exiting an outlet into a space. The method includes operating a pump to provide liquid desiccant to the liquid desiccant dehumidifier and sensing a temperature of an airstream at the outlet of the indirect evaporative cooler. The method includes comparing the temperature of the airstream at the outlet to a setpoint temperature at the outlet and controlling the pump to set the flow rate of the liquid desiccant. The method includes sensing space temperature, comparing the space temperature with a setpoint temperature, and controlling the airflow control device to set the flow rate of the supply air based on the comparison.

  4. The seasonal performance of a liquid-desiccant air conditioner

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lowenstein, A.; Novosel, D.

    1995-08-01

    Prior reports on liquid-desiccant systems have focused on their steady-state operation at ARI design conditions. By studying their performance during an entire cooling season, the computer modeling presented here shows that liquid-desiccant systems can have a very high seasonal coefficient of performance (COP). For a liquid-desiccant system that uses a double-effect boiler, COPs ranging from 1.44 in a humid location (Houston) to 2.24 in a dry location (Phoenix) are achieved by fully exploiting indirect evaporative cooling and providing only the minimum latent cooling needed to meet the loads on the building. This minimizes the amount of water absorbed by themore » desiccant and, hence, the amount of thermal energy needed to regenerate it. In applications where latent loads are very high, such as processing the high volumes of ventilation air required to maintain good indoor air quality, the liquid-desiccant air conditioner again has an advantage over vapor-compression equipment. In this study, a liquid-desiccant system is modeled that cools and dehumidifies only the ventilation air of an office building in Atlanta. Although processing an airstream that is only 25% of the total air delivered to the building, the liquid-desiccant system is able to meet 52% of the building`s seasonal cooling requirements and reduce the building`s peak electrical demand by about 47%.« less

  5. 40 CFR 63.8243 - What equations and procedures must I use to demonstrate continuous compliance?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ....8243 What equations and procedures must I use to demonstrate continuous compliance? (a) By-product... determine the g Hg/Mg Cl2 produced from all by-product hydrogen streams and all end box ventilation system... weekly mercury emission rate in grams per week for each by-product hydrogen stream and for each end box...

  6. Validity of thermally-driven small-scale ventilated filling box models

    NASA Astrophysics Data System (ADS)

    Partridge, Jamie L.; Linden, P. F.

    2013-11-01

    The majority of previous work studying building ventilation flows at laboratory scale have used saline plumes in water. The production of buoyancy forces using salinity variations in water allows dynamic similarity between the small-scale models and the full-scale flows. However, in some situations, such as including the effects of non-adiabatic boundaries, the use of a thermal plume is desirable. The efficacy of using temperature differences to produce buoyancy-driven flows representing natural ventilation of a building in a small-scale model is examined here, with comparison between previous theoretical and new, heat-based, experiments.

  7. Parametric laws to model urban pollutant dispersion with a street network approach

    NASA Astrophysics Data System (ADS)

    Soulhac, L.; Salizzoni, P.; Mejean, P.; Perkins, R. J.

    2013-03-01

    This study discusses the reliability of the street network approach for pollutant dispersion modelling in urban areas. This is essentially based on a box model, with parametric relations that explicitly model the main phenomena that contribute to the street canyon ventilation: the mass exchanges between the street and the atmosphere, the pollutant advection along the street axes and the pollutant transfer at street intersections. In the first part of the paper the focus is on the development of a model for the bulk transfer street/atmosphere, which represents the main ventilation mechanisms for wind direction that are almost perpendicular to the axis of the street. We then discuss the role of the advective transfer along the street axis on its ventilation, depending on the length of the street and the direction of the external wind. Finally we evaluate the performances of a box model integrating parametric exchange laws for these transfer phenomena. To that purpose we compare the prediction of the model to wind tunnel experiments of pollutant dispersion within a street canyon placed in an idealised urban district.

  8. 40 CFR 63.8240 - What are my monitoring requirements?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Mercury Emissions From Mercury Cell...? For each by-product hydrogen stream, each end box ventilation system vent, and each mercury thermal...

  9. 40 CFR 63.8240 - What are my monitoring requirements?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Mercury Emissions From Mercury Cell...? For each by-product hydrogen stream, each end box ventilation system vent, and each mercury thermal...

  10. 40 CFR 63.8240 - What are my monitoring requirements?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Mercury Emissions From Mercury Cell...? For each by-product hydrogen stream, each end box ventilation system vent, and each mercury thermal...

  11. 40 CFR 63.8240 - What are my monitoring requirements?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Mercury Emissions From Mercury Cell...? For each by-product hydrogen stream, each end box ventilation system vent, and each mercury thermal...

  12. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Baxter, Van D.; Rice, C. Keith; Munk, Jeffrey D.

    Between October 2007 and September 2017, Oak Ridge National Laboratory (ORNL) and Lennox Industries, Inc. (Lennox) engaged in a Cooperative Research and Development Agreement (CRADA) to develop an air-source integrated heat pump (AS-IHP) system for the US residential market. The Lennox AS-IHP concept consisted of a high-efficiency air-source heat pump (ASHP) for space heating and cooling services and a separate heat pump water heater/dehumidifier (WH/DH) module for domestic water heating and dehumidification (DH) services. A key feature of this system approach with the separate WH/DH is capability to pretreat (i.e., dehumidify) ventilation air and dedicated whole-house DH independent of themore » ASHP. Two generations of laboratory prototype WH/DH units were designed, fabricated, and lab tested. Performance maps for the system were developed using the latest research version of the US Department of Energy/ORNL heat pump design model (Rice 1992; Rice and Jackson 2005; Shen et al. 2012) as calibrated against the lab test data. These maps served as the input to TRNSYS (Solar Energy Laboratory et al. 2010) to predict annual performance relative to a baseline suite of equipment meeting minimum efficiency standards in effect in 2006 (i.e., a combination of an ASHP with a seasonal energy efficiency ratio (SEER) of 13 and resistance water heater with an energy factor (EF) of 0.9). Predicted total annual energy savings (based on use of a two-speed ASHP and the second-generation WH/DH prototype for the AS-IHP), while providing space conditioning, water heating, and dehumidification for a tight, well-insulated 2600 ft2 (242 m2) house at three US locations, ranged from 33 to 36%, averaging 35%, relative to the baseline system. The lowest savings were seen at the cold-climate Chicago location. Predicted energy use for water heating was reduced by about 50 to 60% relative to a resistance WH.« less

  13. 40 CFR 63.8240 - What are my monitoring requirements?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) National Emission Standards for Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali...-product hydrogen stream, each end box ventilation system vent, and each mercury thermal recovery unit vent...

  14. Models for nearly every occasion: Part I - One box models.

    PubMed

    Hewett, Paul; Ganser, Gary H

    2017-01-01

    The standard "well mixed room," "one box" model cannot be used to predict occupational exposures whenever the scenario involves the use of local controls. New "constant emission" one box models are proposed that permit either local exhaust or local exhaust with filtered return, coupled with general room ventilation or the recirculation of a portion of the general room exhaust. New "two box" models are presented in Part II of this series. Both steady state and transient models were developed. The steady state equation for each model, including the standard one box steady state model, is augmented with an additional factor reflecting the fraction of time the substance was generated during each task. This addition allows the easy calculation of the average exposure for cyclic and irregular emission patterns, provided the starting and ending concentrations are zero or near zero, or the cumulative time across all tasks is long (e.g., several tasks to a full shift). The new models introduce additional variables, such as the efficiency of the local exhaust to immediately capture freshly generated contaminant and the filtration efficiency whenever filtered exhaust is returned to the workspace. Many of the model variables are knowable (e.g., room volume and ventilation rate). A structured procedure for calibrating a model to a work scenario is introduced that can be applied to both continuous and cyclic processes. The "calibration" procedure generates estimates of the generation rate and all of remaining unknown model variables.

  15. Evaluation of Containment Boxes as a Fire Mitigation Method in Elevated Oxygen Conditions

    NASA Technical Reports Server (NTRS)

    Juarez, Alfredo; Harper, Susana; Perez, Horacio

    2016-01-01

    NASA performed testing to evaluate the efficacy of fire containment boxes without forced ventilation. Configurational flammability testing was performed on a simulation avionics box replicating critical design features and filled with materials possessing representative flammability characteristics. This paper discusses the box's ability, under simulated end-use conditions, to inhibit the propagation of combustion to surrounding materials. Analysis was also performed to evaluate the potential for the fire containment box to serve as an overheat/ignition source to temperature sensitive equipment (such as items with lithium-ion batteries). Unrealistically severe combustion scenarios were used as a means to better understand the fire containment mechanism. These scenarios were achieved by utilizing materials/fuels not typically used in space vehicles due to flammability concerns. Oxygen depletion, during combustion within the fire containment boxes, drove self-extinguishment and proved an effective method of fire containment

  16. [The design of heat dissipation of the field low temperature box for storage and transportation].

    PubMed

    Wei, Jiancang; Suin, Jianjun; Wu, Jian

    2013-02-01

    Because of the compact structure of the field low temperature box for storage and transportation, which is due to the same small space where the compressor, the condenser, the control circuit, the battery and the power supply device are all placed in, the design for heat dissipation and ventilation is of critical importance for the stability and reliability of the box. Several design schemes of the heat dissipation design of the box were simulated using the FLOEFD hot fluid analysis software in this study. Different distributions of the temperature field in every design scheme were constructed intimately in the present study. It is well concluded that according to the result of the simulation analysis, the optimal heat dissipation design is decent for the field low temperature box for storage and transportation, and the box can operate smoothly for a long time using the results of the design.

  17. 40 CFR 63.8184 - What parts of my plant does this subpart cover?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... in the manufacture of product chlorine, product caustic, and by-product hydrogen at a plant site. This subpart covers mercury emissions from by-product hydrogen streams, end box ventilation system...

  18. Measure Guideline: Optimizing the Configuration of Flexible Duct Junction Boxes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Beach, R.; Burdick, A.

    2014-03-01

    This measure guideline offers additional recommendations to heating, ventilation, and air conditioning (HVAC) system designers for optimizing flexible duct, constant-volume HVAC systems using junction boxes within Air Conditioning Contractors of America (ACCA) Manual D guidance. IBACOS used computational fluid dynamics software to explore and develop guidance to better control the airflow effects of factors that may impact pressure losses within junction boxes among various design configurations. These recommendations can help to ensure that a system aligns more closely with the design and the occupants' comfort expectations. Specifically, the recommendations described herein show how to configure a rectangular box with fourmore » outlets, a triangular box with three outlets, metal wyes with two outlets, and multiple configurations for more than four outlets. Designers of HVAC systems, contractors who are fabricating junction boxes on site, and anyone using the ACCA Manual D process for sizing duct runs will find this measure guideline invaluable for more accurately minimizing pressure losses when using junction boxes with flexible ducts.« less

  19. Characterization of a starch based desiccant wheel dehumidifier

    NASA Astrophysics Data System (ADS)

    Beery, Kyle Edward

    Starch, cellulose, and hemicellulose have an affinity for water, and adsorb water vapor from air. Materials made from combinations of these biobased sugar polymers also have been found to possess adsorptive properties. An interesting possible application of these starch-based adsorbents is the desiccant wheel dehumidifier. The desiccant wheel dehumidifier is used in conjunction with a standard air conditioning system. In this process, ambient air is passed through a stationary section while a wheel packed with desiccant rotates through that section. The desiccant adsorbs humidity (latent load) from the air, and the air conditioning system then cools the air (sensible load). Several starch based adsorbents were developed and tested for adsorptive capacity in a new high throughput screening system. The best formulations from the high throughput screening system, also taking into account economic considerations and structural integrity, were considered for use in the desiccant wheel dehumidifier. A suitable adsorbent was chosen and formulated into a matrix structure for the desiccant wheel system. A prototype desiccant wheel system was constructed and the performance was investigated under varying regeneration temperatures and rotation speeds. The results from the experiments showed that the starch based desiccant wheel dehumidification system does transfer moisture from the inlet process stream to the outlet regeneration stream. The DESSIM model was modified for the starch based adsorbent and compared to the experimental results. Also, the results when the wheel parameters were varied were compared to the predicted results from the model. The results given by the starch based desiccant wheel system show the desired proof of concept.

  20. Technology Solutions Case Study: Improving Comfort in Hot-Humid Climates with a Whole-House Dehumidifier

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    None

    2013-11-01

    In order to quantify the performance of a combined whole-house dehumidifier (WHD) AC system, researchers from the Consortium of Advanced Residential Buildings (CARB) team monitored the operation of two Lennox AC systems coupled with a Honeywell DH150 TrueDRY whole-house dehumidifier for a six-month period. By using a WHD to control moisture levels (latent cooling) and optimizing a central AC to control temperature (sensible cooling), improvements in comfort can be achieved while reducing utility costs. Indoor comfort for this study was defined as maintaining indoor conditions at below 60% RH and a humidity ratio of 0.012 lbm/lbm while at common drymore » bulb set point temperatures of 74°-80°F. In addition to enhanced comfort, controlling moisture to these levels can reduce the risk of other potential issues such as mold growth, pests, and building component degradation. Because a standard AC must also reduce dry bulb air temperature in order to remove moisture, a WHD is typically needed to support these latent loads when sensible heat removal is not desired.« less

  1. 40 CFR 63.8226 - What are my general requirements for complying with this subpart?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... From Mercury Cell Chlor-Alkali Plants Operation and Maintenance Requirements § 63.8226 What are my... emission limitations for by-product hydrogen streams, end box ventilation system vents, and mercury thermal...

  2. 40 CFR 63.8242 - What are the installation, operation, and maintenance requirements for my continuous monitoring...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Continuous Compliance... each by-product hydrogen stream, end box ventilation system vent, and mercury thermal recovery unit...

  3. 40 CFR 63.8226 - What are my general requirements for complying with this subpart?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... From Mercury Cell Chlor-Alkali Plants Operation and Maintenance Requirements § 63.8226 What are my... emission limitations for by-product hydrogen streams, end box ventilation system vents, and mercury thermal...

  4. 40 CFR 63.8242 - What are the installation, operation, and maintenance requirements for my continuous monitoring...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Continuous Compliance... each by-product hydrogen stream, end box ventilation system vent, and mercury thermal recovery unit...

  5. 40 CFR 63.8226 - What are my general requirements for complying with this subpart?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... From Mercury Cell Chlor-Alkali Plants Operation and Maintenance Requirements § 63.8226 What are my... emission limitations for by-product hydrogen streams, end box ventilation system vents, and mercury thermal...

  6. 40 CFR 63.8242 - What are the installation, operation, and maintenance requirements for my continuous monitoring...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Continuous Compliance... each by-product hydrogen stream, end box ventilation system vent, and mercury thermal recovery unit...

  7. 40 CFR 63.8226 - What are my general requirements for complying with this subpart?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... From Mercury Cell Chlor-Alkali Plants Operation and Maintenance Requirements § 63.8226 What are my... emission limitations for by-product hydrogen streams, end box ventilation system vents, and mercury thermal...

  8. 40 CFR 63.8226 - What are my general requirements for complying with this subpart?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... From Mercury Cell Chlor-Alkali Plants Operation and Maintenance Requirements § 63.8226 What are my... emission limitations for by-product hydrogen streams, end box ventilation system vents, and mercury thermal...

  9. 40 CFR 63.8242 - What are the installation, operation, and maintenance requirements for my continuous monitoring...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Continuous Compliance... each by-product hydrogen stream, end box ventilation system vent, and mercury thermal recovery unit...

  10. 40 CFR 63.8242 - What are the installation, operation, and maintenance requirements for my continuous monitoring...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Continuous Compliance... each by-product hydrogen stream, end box ventilation system vent, and mercury thermal recovery unit...

  11. 40 CFR 63.8190 - What emission limitations must I meet?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ton of chlorine produced) from all by-product hydrogen streams and all end box ventilation system... chlorine produced (6.59 × 10−5 pounds of mercury per ton of chlorine produced) from all by-product hydrogen...

  12. Improvements in and actual performance of the Plant Experiment Unit onboard Kibo, the Japanese experiment module on the international space station

    NASA Astrophysics Data System (ADS)

    Yano, Sachiko; Kasahara, Haruo; Masuda, Daisuke; Tanigaki, Fumiaki; Shimazu, Toru; Suzuki, Hiromi; Karahara, Ichirou; Soga, Kouichi; Hoson, Takayuki; Tayama, Ichiro; Tsuchiya, Yoshikazu; Kamisaka, Seiichiro

    2013-03-01

    In 2004, Japan Aerospace Exploration Agency developed the engineered model of the Plant Experiment Unit and the Cell Biology Experiment Facility. The Plant Experiment Unit was designed to be installed in the Cell Biology Experiment Facility and to support the seed-to-seed life cycle experiment of Arabidopsis plants in space in the project named Space Seed. Ground-based experiments to test the Plant Experiment Unit showed that the unit needed further improvement of a system to control the water content of a seedbed using an infrared moisture analyzer and that it was difficult to keep the relative humidity inside the Plant Experiment Unit between 70 and 80% because the Cell Biology Experiment Facility had neither a ventilation system nor a dehumidifying system. Therefore, excess moisture inside the Cell Biology Experiment Facility was removed with desiccant bags containing calcium chloride. Eight flight models of the Plant Experiment Unit in which dry Arabidopsis seeds were fixed to the seedbed with gum arabic were launched to the International Space Station in the space shuttle STS-128 (17A) on August 28, 2009. Plant Experiment Unit were installed in the Cell Biology Experiment Facility with desiccant boxes, and then the Space Seed experiment was started in the Japanese Experiment Module, named Kibo, which was part of the International Space Station, on September 10, 2009 by watering the seedbed and terminated 2 months later on November 11, 2009. On April 19, 2010, the Arabidopsis plants harvested in Kibo were retrieved and brought back to Earth by the space shuttle mission STS-131 (19A). The present paper describes the Space Seed experiment with particular reference to the development of the Plant Experiment Unit and its actual performance in Kibo onboard the International Space Station. Downlinked images from Kibo showed that the seeds had started germinating 3 days after the initial watering. The plants continued growing, producing rosette leaves, inflorescence stems, flowers, and fruits in the Plant Experiment Unit. In addition, the senescence of rosette leaves was found to be delayed in microgravity.

  13. Effects of ventilation on hyaluronan and protein concentration in pleural liquid of anesthetized and conscious rabbits.

    PubMed

    Wang, P M; Lai-Fook, S J

    1998-01-01

    The hypothesis of this study is that pleural lubrication is enhanced by hyaluronan acting as a boundary lubricant in pleural liquid and by pleural filtration as reflected in changes in protein concentration with ventilation. Anesthetized rabbits were injected intravenously with Evans blue dye and ventilated with 100% O2 at either of two levels of ventilation for 6 h. Postmortem values of hyaluronan, total protein, and Evans blue-dyed albumin (EBA) concentrations in pleural liquid were greater at the higher ventilation, consistent with increases in boundary lubrication, pleural membrane permeability, and pleural filtration. To determine whether these effects were caused by hyperoxia or anesthesia, conscious rabbits were ventilated with either 3% CO2 or room air in a box for 6, 12, or 24 h. Similar to the anesthetized rabbits, pleural liquid hyaluronan concentration after 24 h was higher in the conscious rabbits with the hypercapnic-induced greater ventilation. By contrast, the time course of total protein and EBA in pleural liquid was similar in both groups of conscious rabbits, indicating no effect of ventilation on pleural permeability. The increase in pleural liquid hyaluronan concentration might be the result of mesothelial cell stimulation by a ventilation-induced increase in pleural liquid shear stress.

  14. The addition of a mobile ultra-clean exponential laminar airflow screen to conventional operating room ventilation reduces bacterial contamination to operating box levels.

    PubMed

    Friberg, S; Ardnor, B; Lundholm, R; Friberg, B

    2003-10-01

    A mobile screen producing ultra-clean exponential laminar airflow (LAF) was investigated as an addition to conventional turbulent/mixing operating room (OR) ventilation (16 air changes/h). The evaluation was performed in a small OR (50 m(3)) during 60 standardized operations for groin hernia including mesh implantation. The additional ventilation was used in 50 of the operations. The LAF passed from the foot-end of the OR table over the instrument and surgical area. Strict hygiene OR procedures including tightly woven and non-woven OR clothing were used. Sedimentation rates were recorded at the level of the patients' chests (N=60) (i.e. the air had passed the surgical team) and in the periphery of the OR. In addition bacterial air contamination was studied above the patients' chests in all 10 operations without the additional LAF and in 12 with the LAF. The screen reduced the mean counts of sedimenting bacteria (cfu/m(2)/h) on the patients' chests from 775 without the screen to 355 (P=0.0003). The screen also reduced the mean air counts of bacteria (cfu/m(3)) above the patients' chests from 27 to 9 (P=0.0001). No significant differences in mean sedimentation rates (cfu/m(2)/h) existed in the periphery of the OR where 628 without and 574 with screen were recorded. During the follow-up period of six months no surgical site infections were detected. In conclusion when the mobile LAF screen was added to conventional OR ventilation the counts of aerobic airborne and sedimenting bacteria-carrying particles downstream of the surgical team were reduced to the levels achieved with complete ultra-clean LAF OR ventilation (operating box).

  15. 40 CFR 63.8230 - By what date must I conduct performance tests or other initial compliance demonstrations?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Initial Compliance... § 63.8190(a)(2) for by-product hydrogen streams and end box ventilation system vents and the applicable...

  16. 40 CFR 63.8230 - By what date must I conduct performance tests or other initial compliance demonstrations?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Initial Compliance... § 63.8190(a)(2) for by-product hydrogen streams and end box ventilation system vents and the applicable...

  17. 40 CFR 63.8230 - By what date must I conduct performance tests or other initial compliance demonstrations?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Initial Compliance... § 63.8190(a)(2) for by-product hydrogen streams and end box ventilation system vents and the applicable...

  18. 40 CFR 63.8230 - By what date must I conduct performance tests or other initial compliance demonstrations?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Initial Compliance... § 63.8190(a)(2) for by-product hydrogen streams and end box ventilation system vents and the applicable...

  19. 40 CFR 63.8230 - By what date must I conduct performance tests or other initial compliance demonstrations?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Initial Compliance Requirements § 63.8230...(a)(2) for by-product hydrogen streams and end box ventilation system vents and the applicable...

  20. Transient performance and temperature field of a natural convection air dehumidifier loop

    NASA Astrophysics Data System (ADS)

    Fazilati, Mohammad Ali; Sedaghat, Ahmad; Alemrajabi, Ali-Akbar

    2017-07-01

    In this paper, transient performance of the previously introduced natural convection heat and mass transfer loop is investigated for an air dehumidifier system. The performance of the loop is studied in different conditions of heat source/heat sink temperature and different startup desiccant concentrations. Unlike conventional loops, it is observed that natural convection of the fluid originates from the heat sink towards the heat source. The proper operation of the cycle is highly dependent on the heat sink/heat source temperatures. To reduce the time constant of the system, a proper desiccant concentration should be adopted for charge of the loop.

  1. Performance analysis of an air drier for a liquid dehumidifier solar air conditioning system

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Queiroz, A.G.; Orlando, A.F.; Saboya, F.E.M.

    1988-05-01

    A model was developed for calculating the operating conditions of a non-adiabatic liquid dehumidifier used in solar air conditioning systems. In the experimental facility used for obtaining the data, air and triethylene glycol circulate countercurrently outside staggered copper tubes which are the filling of an absorption tower. Water flows inside the copper tubes, thus cooling the whole system and increasing the mass transfer potential for drying air. The methodology for calculating the mass transfer coefficient is based on the Merkel integral approach, taking into account the lowering of the water vapor pressure in equilibrium with the water glycol solution.

  2. 40 CFR 61.53 - Stack sampling.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... operator employing mercury chlor-alkali cell(s) shall test emissions from hydrogen streams according to... the Administrator, for a minimum of 2 years. (b) Mercury chlor-alkali plant—hydrogen and end-box.... (c) Mercury chlor-alkali plants—cell room ventilation system. (1) Stationary sources using mercury...

  3. 40 CFR 61.53 - Stack sampling.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... operator employing mercury chlor-alkali cell(s) shall test emissions from hydrogen streams according to... the Administrator, for a minimum of 2 years. (b) Mercury chlor-alkali plant—hydrogen and end-box.... (c) Mercury chlor-alkali plants—cell room ventilation system. (1) Stationary sources using mercury...

  4. 40 CFR 61.53 - Stack sampling.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... operator employing mercury chlor-alkali cell(s) shall test emissions from hydrogen streams according to... the Administrator, for a minimum of 2 years. (b) Mercury chlor-alkali plant—hydrogen and end-box.... (c) Mercury chlor-alkali plants—cell room ventilation system. (1) Stationary sources using mercury...

  5. Effect of heated-air blanket on the dispersion of squames in an operating room.

    PubMed

    He, X; Karra, S; Pakseresht, P; Apte, S V; Elghobashi, S

    2018-05-01

    High-fidelity, predictive fluid flow simulations of the interactions between the rising thermal plumes from forced air warming blower and the ultra-clean ventilation air in an operating room (OR) are conducted to explore whether this complex flow can impact the dispersion of squames to the surgical site. A large-eddy simulation, accurately capturing the spatiotemporal evolution of the flow in 3 dimensions together with the trajectories of squames, is performed for a realistic OR consisting of an operating table (OT), side tables, surgical lamps, medical staff, and a patient. Two cases are studied with blower-off and blower-on together with Lagrangian trajectories of 3 million squames initially placed on the floor surrounding the OT. The large-eddy simulation results show that with the blower-off, squames are quickly transported by the ventilation air away from the table and towards the exit grilles. In contrast, with the hot air blower turned on, the ventilation airflow above and below the OT is disrupted significantly. The rising thermal plumes from the hot air blower drag the squames above the OT and the side tables and then they are advected downwards toward the surgical site by the ventilation air from the ceiling. Temporal history of the number of squames reaching 4 imaginary boxes surrounding the side tables, the OT, and the patient's knee shows that several particles reach these boxes for the blower-on case. © 2018 The Authors International Journal for Numerical Methods in Biomedical Engineering Published by John Wiley & Sons Ltd.

  6. Study of the application of solar chemical dehumidification system to wind tunnel facilities of NASA Lewis Research Center at Cleveland, Ohio

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Energy utilization and cost payback analyses were prepared for proposed modifications. A 50,000 CFM standard compact packaged solid desiccant dehumidifier utilizing high temperature hot water (HTHW) for desiccant regeneration was added. The HTHW is generated by utilizing solar energy and is stored in a storage tank. A steam boiler is provided as a back-up for the solar system. A 50,000 CFM standard compact package solid desiccant dehumidifier utilizing high temperature hot water (HTHW) for desiccant regeneration was added. The HTHW is generated by utilizing a steam boiler and a heat exchanger and is stored in a storage tank.

  7. 40 CFR 63.8256 - What records must I keep?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) National Emission Standards for Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali... malfunction. (b) Records associated with the by-product hydrogen stream and end box ventilation system vent... the work practice standards. (1) If you choose not to institute a cell room monitoring program...

  8. 40 CFR 63.8256 - What records must I keep?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) National Emission Standards for Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali... malfunction. (b) Records associated with the by-product hydrogen stream and end box ventilation system vent... the work practice standards. (1) If you choose not to institute a cell room monitoring program...

  9. 40 CFR 63.8256 - What records must I keep?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) National Emission Standards for Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali... malfunction. (b) Records associated with the by-product hydrogen stream and end box ventilation system vent... the work practice standards. (1) If you choose not to institute a cell room monitoring program...

  10. 40 CFR 63.8256 - What records must I keep?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) National Emission Standards for Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali... malfunction. (b) Records associated with the by-product hydrogen stream and end box ventilation system vent... the work practice standards. (1) If you choose not to institute a cell room monitoring program...

  11. 40 CFR 63.8256 - What records must I keep?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) National Emission Standards for Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali... malfunction. (b) Records associated with the by-product hydrogen stream and end box ventilation system vent... the work practice standards. (1) If you choose not to institute a cell room monitoring program...

  12. 78 FR 42929 - Foreign-Trade Zone (FTZ) 41-Milwaukee, Wisconsin, Notification of Proposed Production Activity...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-18

    ... rubber articles, cartons, bags, corrugated boxes with fillers, instruction sheets, range hood filters, bathroom mirrors, filters for whole house ventilation systems, cold- rolled steel for manufacturing, flat..., damper or filter springs for grille, stainless steel kitchen backsplashes, brackets, aluminum stainless...

  13. 40 CFR 63.8252 - What notifications must I submit and when?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Mercury Emissions From Mercury Cell... to conduct for by-product hydrogen streams and end box ventilation system vents and for mercury... a cell room monitoring program according to § 63.8192(g), a certification that you are operating...

  14. 40 CFR 63.8252 - What notifications must I submit and when?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Mercury Emissions From Mercury Cell... to conduct for by-product hydrogen streams and end box ventilation system vents and for mercury... a cell room monitoring program according to § 63.8192(g), a certification that you are operating...

  15. 40 CFR 63.8252 - What notifications must I submit and when?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Mercury Emissions From Mercury Cell... to conduct for by-product hydrogen streams and end box ventilation system vents and for mercury... a cell room monitoring program according to § 63.8192(g), a certification that you are operating...

  16. 40 CFR 63.8252 - What notifications must I submit and when?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Mercury Emissions From Mercury Cell... to conduct for by-product hydrogen streams and end box ventilation system vents and for mercury... a cell room monitoring program according to § 63.8192(g), a certification that you are operating...

  17. 40 CFR 63.8184 - What parts of my plant does this subpart cover?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... in the manufacture of product chlorine, product caustic, and by-product hydrogen at a plant site. This subpart covers mercury emissions from by-product hydrogen streams, end box ventilation system vents, and fugitive emission sources associated with cell rooms, hydrogen systems, caustic systems, and...

  18. 40 CFR 63.8184 - What parts of my plant does this subpart cover?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... in the manufacture of product chlorine, product caustic, and by-product hydrogen at a plant site. This subpart covers mercury emissions from by-product hydrogen streams, end box ventilation system vents, and fugitive emission sources associated with cell rooms, hydrogen systems, caustic systems, and...

  19. 40 CFR 63.8184 - What parts of my plant does this subpart cover?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... in the manufacture of product chlorine, product caustic, and by-product hydrogen at a plant site. This subpart covers mercury emissions from by-product hydrogen streams, end box ventilation system vents, and fugitive emission sources associated with cell rooms, hydrogen systems, caustic systems, and...

  20. 40 CFR 63.8184 - What parts of my plant does this subpart cover?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... in the manufacture of product chlorine, product caustic, and by-product hydrogen at a plant site. This subpart covers mercury emissions from by-product hydrogen streams, end box ventilation system vents, and fugitive emission sources associated with cell rooms, hydrogen systems, caustic systems, and...

  1. 30 CFR 75.333 - Ventilation controls.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...), 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959; http://www.astm.org. This....astm.org. This incorporation by reference was approved by the Director of the Federal Register in... Conshohocken, PA 19428-2959; http://www.astm.org. This incorporation by reference was approved by the Director...

  2. 76 FR 58345 - Energy Conservation Program: Test Procedures for Residential Dishwashers, Dehumidifiers, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-20

    ...Where appropriate, the U.S. Department of Energy (DOE) has proposed to amend its test procedures for residential dishwashers, dehumidifiers, and conventional cooking products (which includes cooktops, ovens, and ranges) to include provisions for measuring standby mode and off mode energy consumption, as required by the Energy Independence and Security Act of 2007 (EISA 2007). These test procedure amendments would incorporate by reference certain provisions of the International Electrotechnical Commission (IEC) Standard 62301, ``Household electrical appliances--Measurement of standby power.'' Since publication of DOE's initial proposal in December 2010, the IEC has replaced the First Edition of this standard with the current Second Edition. This supplemental notice of proposed rulemaking proposes to incorporate the latest edition of IEC Standard 62301.

  3. Solar powered dehumidifier apparatus

    DOEpatents

    Jebens, Robert W.

    1980-12-30

    A thermally insulated light transmitting housing forms a chamber containing a desiccant and having a first gas port open to the ambient and a second gas port connected by a two way valve to a volume to be dried. Solar energy transmitted through the housing heats and dries the desiccant. The increased air pressure due to the heating of the volume to be dried causes the air from the volume to be expelled through the valve into the chamber. The desiccant is then cooled by shielding it from solar energy before the volume cools thereby increasing its moisture absorbing capacity. Then the volume is allowed to cool drawing dehumidified air through the desiccant and the valve into the volume to be dried. This cycle is then repeated.

  4. 7 CFR 305.27 - Forced hot air treatment schedules.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., and T103-d-2. (1)Temperature sensors must be inserted into the centers of the largest fruits. The number of sensors must be approved in advance by APHIS. Sensors must be physically placed in various... trays, bulk bins, or ventilated boxes) must be loaded into the treatment chamber, and sensors must be...

  5. 40 CFR 63.8236 - How do I demonstrate initial compliance with the emission limitations and work practice standards?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Initial Compliance... standards? (a) For each mercury cell chlor-alkali production facility, you have demonstrated initial compliance with the applicable emission limit for by-product hydrogen streams and end box ventilation system...

  6. 40 CFR 63.8236 - How do I demonstrate initial compliance with the emission limitations and work practice standards?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Initial Compliance... standards? (a) For each mercury cell chlor-alkali production facility, you have demonstrated initial compliance with the applicable emission limit for by-product hydrogen streams and end box ventilation system...

  7. 40 CFR 63.8236 - How do I demonstrate initial compliance with the emission limitations and work practice standards?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Initial Compliance... standards? (a) For each mercury cell chlor-alkali production facility, you have demonstrated initial compliance with the applicable emission limit for by-product hydrogen streams and end box ventilation system...

  8. 40 CFR 63.8236 - How do I demonstrate initial compliance with the emission limitations and work practice standards?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Initial Compliance... standards? (a) For each mercury cell chlor-alkali production facility, you have demonstrated initial compliance with the applicable emission limit for by-product hydrogen streams and end box ventilation system...

  9. Measure Guideline: Optimizing the Configuration of Flexible Duct Junction Boxes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Beach, R.; Burdick, A.

    2014-03-01

    This measure guideline offers additional recommendations to heating, ventilation, and air conditioning (HVAC) system designers for optimizing flexible duct, constant-volume HVAC systems using junction boxes within Air Conditioning Contractors of America (ACCA) Manual D guidance (Rutkowski, H. Manual D -- Residential Duct Systems, 3rd edition, Version 1.00. Arlington, VA: Air Conditioning Contractors of America, 2009.). IBACOS used computational fluid dynamics software to explore and develop guidance to better control the airflow effects of factors that may impact pressure losses within junction boxes among various design configurations (Beach, R., Prahl, D., and Lange, R. CFD Analysis of Flexible Duct Junction Boxmore » Design. Golden, CO: National Renewable Energy Laboratory, submitted for publication 2013). These recommendations can help to ensure that a system aligns more closely with the design and the occupants' comfort expectations. Specifically, the recommendations described herein show how to configure a rectangular box with four outlets, a triangular box with three outlets, metal wyes with two outlets, and multiple configurations for more than four outlets. Designers of HVAC systems, contractors who are fabricating junction boxes on site, and anyone using the ACCA Manual D process for sizing duct runs will find this measure guideline invaluable for more accurately minimizing pressure losses when using junction boxes with flexible ducts.« less

  10. A tracer study of ventilation in the Japan/East Sea

    NASA Astrophysics Data System (ADS)

    Postlethwaite, C. F.; Rohling, E. J.; Jenkins, W. J.; Walker, C. F.

    2005-06-01

    During the Circulation Research in East Asian Marginal Seas (CREAMS) summer cruises in 1999, a suite of samples was collected for tracer analysis. Oxygen isotopes combined with tritium-helium ventilation timescales and noble gas measurements give unique insights into the ventilation of water masses in the Japan/East Sea (JES). In particular, noble gases and oxygen isotopes are indicators of brine rejection, which may assist in explaining the recent changes observed in the ventilation of the JES. Oxygen isotope data presented here indicate that both thermally driven convection and brine rejection have played significant roles in deep-water formation but that brine rejection is unlikely to be a significant contributor at the moment. A 6-box ventilation model of the JES, calibrated with tritium and helium-3 measurements, performed better when a significant decrease of dense-water formation rates in the mid-1960s was incorporated. However, the model calculations suggest that Japan Sea Intermediate Water formation is still occurring. Subduction of sea-ice melt water may be a significant ventilation mechanism for this water mass, based on an argon saturation minimum at the recently ventilated salinity minimum in the northwestern sector of the JES. The salinity and oxygen isotope budgets imply a potential bottom-water formation rate of 3.97±0.89×10 12 m 3 yr -1 due to brine rejection, which could account for a time averaged fraction of between 25% and 35% of the ventilation of subsurface water formation in the JES.

  11. Contaminants in ventilated filling boxes

    NASA Astrophysics Data System (ADS)

    Bolster, D. T.; Linden, P. F.

    While energy efficiency is important, the adoption of energy-efficient ventilation systems still requires the provision of acceptable indoor air quality. Many low-energy systems, such as displacement or natural ventilation, rely on temperature stratification within the interior environment, always extracting the warmest air from the top of the room. Understanding buoyancy-driven convection in a confined ventilated space is key to understanding the flow that develops with many of these modern low-energy ventilation schemes. In this work we study the transport of an initially uniformly distributed passive contaminant in a displacement-ventilated space. Representing a heat source as an ideal sourced of buoyancy, analytical and numerical models are developed that allow us to compare the average efficiency of contaminant removal between traditional mixing and modern low-energy systems. A set of small-scale analogue laboratory experiments was also conducted to further validate our analytical and numerical solutions.We find that on average traditional and low-energy ventilation methods are similar with regard to pollutant flushing efficiency. This is because the concentration being extracted from the system at any given time is approximately the same for both systems. However, very different vertical concentration gradients exist. For the low-energy system, a peak in contaminant concentration occurs at the temperature interface that is established within the space. This interface is typically designed to sit at some intermediate height in the space. Since this peak does not coincide with the extraction point, displacement ventilation does not offer the same benefits for pollutant flushing as it does for buoyancy removal.

  12. 49 CFR 173.307 - Exceptions for compressed gases.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... subchapter. (3) Balls used for sports. (4) Refrigerating machines, including dehumidifiers and air... of a flammable, non-toxic liquefied gas. (5) Manufactured articles or apparatuses, each containing...

  13. Evaluation of the indoor air quality minimum ventilation rate procedure for use in California retail buildings.

    PubMed

    Dutton, S M; Mendell, M J; Chan, W R; Barrios, M; Sidheswaran, M A; Sullivan, D P; Eliseeva, E A; Fisk, W J

    2015-02-01

    This research assesses benefits of adding to California Title-24 ventilation rate (VR) standards a performance-based option, similar to the American Society of Heating, Refrigerating, and Air Conditioning Engineers 'Indoor Air Quality Procedure' (IAQP) for retail spaces. Ventilation rates and concentrations of contaminants of concern (CoC) were measured in 13 stores. Mass balance models were used to estimate 'IAQP-based' VRs that would maintain concentrations of all CoCs below health- or odor-based reference concentration limits. An intervention study in a 'big box' store assessed how the current VR, the Title 24-prescribed VR, and the IAQP-based VR (0.24, 0.69, and 1.51 air changes per hour) influenced measured IAQ and perceived of IAQ. Neither current VRs nor Title 24-prescribed VRs would maintain all CoCs below reference limits in 12 of 13 stores. In the big box store, the IAQP-based VR kept all CoCs below limits. More than 80% of subjects reported acceptable air quality at all three VRs. In 11 of 13 buildings, saving energy through lower VRs while maintaining acceptable IAQ would require source reduction or gas-phase air cleaning for CoCs. In only one of the 13 retail stores surveyed, application of the IAQP would have allowed reduced VRs without additional contaminant-reduction strategies. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

  14. Handbook of dehumidification technology

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Brundrett, G.W.

    1987-01-01

    This book shows how dehumidification can alleviate environmental problems in human and industrial spheres which carry major cost implications. The applications of dehumidification, sorbent, air cycle and refrigerant are outlined but the main emphasis is placed on the refrigerant cycle because its applications and product range are the most extensive. A more detailed review of the main applications and opportunities such as housing condensation problems, protection and control in industry and energy saving for swimming pools then follows. Specialist sections on food and flowers and the drying of pressurized gases precede chapters on future developments, economic aspects and a usefulmore » list of further information sources including active research centres. The Contents discussed are: Introduction . Principles . Design considerations for refrigerant dehumidifiers . Domestic applications and dehumidifiers . Swimming pools . Industrial dehumidification . Food and flowers . Drying high pressure gases . Future trends . Economics . Further sources of information.« less

  15. 40 CFR 63.8234 - What equations and procedures must I use for the initial compliance demonstration?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... hydrogen streams and end box ventilation system vents. You must determine the total grams of mercury per Megagram of chlorine production (g Hg/Mg Cl2) of chlorine produced from all by-product hydrogen streams and...) Determine the mercury emission rate for each test run in grams per day for each by-product hydrogen stream...

  16. 40 CFR 63.8234 - What equations and procedures must I use for the initial compliance demonstration?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... hydrogen streams and end box ventilation system vents. You must determine the total grams of mercury per Megagram of chlorine production (g Hg/Mg Cl2) of chlorine produced from all by-product hydrogen streams and...) Determine the mercury emission rate for each test run in grams per day for each by-product hydrogen stream...

  17. 40 CFR 63.8234 - What equations and procedures must I use for the initial compliance demonstration?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... hydrogen streams and end box ventilation system vents. You must determine the total grams of mercury per Megagram of chlorine production (g Hg/Mg Cl2) of chlorine produced from all by-product hydrogen streams and...) Determine the mercury emission rate for each test run in grams per day for each by-product hydrogen stream...

  18. 40 CFR 63.8234 - What equations and procedures must I use for the initial compliance demonstration?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... hydrogen streams and end box ventilation system vents. You must determine the total grams of mercury per Megagram of chlorine production (g Hg/Mg Cl2) of chlorine produced from all by-product hydrogen streams and...) Determine the mercury emission rate for each test run in grams per day for each by-product hydrogen stream...

  19. The influence of temperature on fatigue-crack growth in a mill annealed Ti-6Al-4V alloy

    NASA Technical Reports Server (NTRS)

    Wei, R. P.; Ritter, D. L.

    1972-01-01

    To understand the influence temperature on the rate of fatigue crack growth in high strength metal alloys, constant load amplitude, fatigue crack growth experiments were carried out using a 1/4-inch-thick (6.35 mm) mill annealed Ti-6Al-4V alloy plate as a model material. The rates of fatigue crack growth were determined as a function of temperature, ranging from room temperature to about 290 C (or, about 550 F/563K) and as a function of the crack tip stress intensity factor in a dehumidified high purity argon environment. Limited correlative experiments indicate that dehumidified oxygen and hydrogen have no effect on the rate of fatigue crack growth in this alloy, while distilled water increased the rate of crack growth slightly in the range tested. Companion fractographic examinations suggest that the mechanisms for fatigue crack growth in the various environments are essentially the same.

  20. Jewelry boxes contaminated by Aspergillus oryzae: an occupational health risk?

    PubMed

    Bellanger, Anne-Pauline; Roussel, Anaïs; Millon, Laurence; Delaforge, Marcel; Reboux, Gabriel

    2012-01-01

    In 2009, 100,000 jewelry boxes, manufactured in China, were delivered to a jewelry manufacturer in Besançon, France. All the boxes were contaminated by mold. Because the workers refused to handle these jewelry boxes, the company contacted our laboratory to determine how to deal with the problem. Three choices were available: (1) decontaminate the boxes, (2) return the boxes to the Chinese manufacturer, or (3) destroy the entire shipment. Based on microscopic identification, the culture analysis was positive for A. oryzae. This could not be confirmed by molecular techniques because of the genetic proximity of A. oryzae and A. flavus. Because A. flavus can produce aflatoxins, we tested for them using mass spectrometry. Aflatoxins B1, B2, G1, G2, and M1 were not detected; however, given the specifics of this situation, we could not discard the possibility of the presence of other aflatoxins, such as P1, B3, GM2, and ethoxyaflatoxin B2. We concluded that the contamination by A. oryzae was probably due to food products. However, because of the possible presence of aflatoxins, occupational health risks could not be entirely ruled out. The decision was therefore taken to destroy all the jewelry boxes by incineration. To avoid a similar situation we propose: (1) to maintain conditions limiting mold contamination during production (not eating on the work site, efficient ventilation systems); (2) to desiccate the products before sending them; and (3) to closely control the levels of dampness during storage and transport.

  1. 1. View from missile site control building (southeast to northwest) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. View from missile site control building (southeast to northwest) of universal missile building. Note earth mounding. On the far right can be seen the exit tunnel; the small "boxes" on top are the roof ventilators. This building was salvaged and sealed after site inactivation - Stanley R. Mickelsen Safeguard Complex, Universal Missile Building, Between Tactical Road South & Patrol Road, Nekoma, Cavalier County, ND

  2. HVAC; Heating, Ventilation, Air Conditioning - Aerosol Duct Sealant

    DTIC Science & Technology

    2016-09-01

    material was applied. Annual energy and cost savings were predicted based on a typical weather year for each site. The installation of the duct...Balance reports; Visible dust streaks on duct work, ceilings near supply diffusers, or electrical boxes; Comfort complaints Specific Leakage...energy consumption , depending on the HVAC system type and the location of the ducts that were sealed. The cost effectiveness of the technology is

  3. An analysis of natural ventilation techniques to achieve indoor comfort in Wal-Mart express

    NASA Astrophysics Data System (ADS)

    O'Dea, Shona

    Despite global efforts to reduce world fossil fuel dependency the world still obtains 81% of its energy from fossil fuels (IEA,2009). Modern renewable alternatives have been around since the mid twentieth century these alternatives have not been integrated into electrical grid systems at the exponential rate required to eradicate fossil fuels dependency. The problem, world energy demand, is too large to be satisfied by anything other than the energy-dense fossil fuels used today. We must change our energy intensive processes in order to conserve energy and hence reduce the demands that alternatives must satisfy. This research aims to identify sustainable design opportunities through the application of innovative technologies for the largest retailer in the US with the view that a viable conservative design measure could be applied to the store model, which is replicated across the country, causing a cumulative and hence larger impact on the company energy consumption as a whole. This paper will present the literature available on the 'big box' industry and Wal-Mart, comfort, natural ventilation and building simulation software and then perform an analysis into the viability of naturally ventilating the Wal-Mart Express sales zone using Monodraught natural ventilation windcatcher products

  4. Membrane humidity control investigation

    NASA Technical Reports Server (NTRS)

    Elam, J.; Ruder, J.; Strumpf, H.

    1974-01-01

    The basic performance data on a hollow fiber membrane unit that removes water from a breathing gas loop by diffusion is presented. Using available permeability data for cellulose acetate, a preliminary design was made of a dehumidifier unit that would meet the problem statement.

  5. [Unplanned extubation in ICU, and the relevance of non-dependent patient variables the quality of care].

    PubMed

    González-Castro, A; Peñasco, Y; Blanco, C; González-Fernández, C; Domínguez, M J; Rodríguez-Borregán, J C

    2014-01-01

    To evaluate, for a consecutive year, the magnitude of unplanned extubation, looking for non-dependent patient variables. Prospective, observational study of cases and controls in a mixed intensive care unit within in a tertiary hospital. Patients were considered cases with more than 24 hours who had an episode of unplanned extubation. Prospective collection of variables case as time of unplanned extubation (collection time), identification of the box where the patient was admitted, presence and type of physical restraint, development of ventilator-associated pneumonia (VAP) and death. There were 17 unplanned extubation in 15 patients, 1.21 unplanned extubation per 100 days of MV. The unplanned extubation had an inhomogeneous spatial distribution (number of boxes). The time distribution of cases compared with controls showed significant differences in time distribution (P=.02). The comparative analysis between cases and controls, showed increased mortality, increased length of ICU stay, longer hospital stay and increased risk for VAP when patients suffer an episode of unplanned extubation. Unplanned extubation occurs most frequently in a given time slot of the day, may play a role in the spatial location of the patient; occurs most often in patients who are in the process of weaning from mechanical ventilation, and develop greater VAP. Copyright © 2014 SECA. Published by Elsevier Espana. All rights reserved.

  6. A physiological comparison of three techniques for reviving sockeye salmon exposed to a severe capture stressor during upriver migration

    PubMed Central

    Raby, Graham D.; Wilson, Samantha M.; Patterson, David A.; Hinch, Scott G.; Clark, Timothy D.; Farrell, Anthony P.; Cooke, Steven J.

    2015-01-01

    Capture of fish in commercial and recreational fisheries causes disruption to their physiological homeostasis and can result in delayed mortality for fish that are released. For fish that are severely impaired, it may be desirable to attempt revival prior to release to reduce the likelihood of post-release mortality. In this study, male sockeye salmon (Oncorhynchus nerka) undergoing their upriver migration were used to examine short-term physiological changes during the following three revival treatments after beach seine capture and air exposure: a pump-powered recovery box that provided ram ventilation at one of two water flow rates; and a cylindrical, in-river recovery bag, which ensured that fish were oriented into the river flow. Beach seine capture followed by a 3 min air exposure resulted in severe impairment of reflexes such that fish could not maintain positive orientation or properly ventilate. All three revival treatments resulted in significant reductions in reflex impairment within 15 min, with full recovery of reflex responses observed within 60–120 min. For most variables measured, including plasma lactate, cortisol and osmolality, there were no significant differences among revival treatments. There was some evidence for impaired recovery in the low-flow recovery box, in the form of higher haematocrit and plasma sodium. These data mirror published recovery profiles for a recovery box study in the marine environment where a survival benefit occurred, suggesting that the methods tested here are viable options for reviving salmon caught in freshwater. Importantly, with most of the benefit to animal vitality accrued in the first 15 min, prolonging recovery when fish become vigorous may not provide added benefit because the confinement itself is likely to serve as a stressor. PMID:27293700

  7. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dutton, Spencer M.; Chan, Wanyu R.; Mendell, Mark J.

    California's building efficiency standards (Title 24) mandate minimum prescribed ventilation rates (VRs) for commercial buildings. Title 24 standards currently include a prescriptive procedure similar to ASHRAE’s prescriptive “ventilation rate procedure”, but does not include an alternative procedure, akin to ASHRAE’s non-prescriptive “indoor air quality procedure” (IAQP). The IAQP determines minimum VRs based on objectively and subjectively evaluated indoor air quality (IAQ). The first primary goal of this study was to determine, in a set of California retail stores, the adequacy of Title 24 VRs and observed current measured VRs in providing the level of IAQ specified through an IAQP process,more » The second primary goal was to evaluate whether several VRs implemented experimentally in a big box store would achieve adequate IAQ, assessed objectively and subjectively. For the first goal, a list of contaminants of concern (CoCs) and reference exposure levels (RELs) were selected for evaluating IAQ. Ventilation rates and indoor and outdoor CoC concentrations were measured in 13 stores, including one “big box” store. Mass balance models were employed to calculate indoor contaminant source strengths for CoCs in each store. Using these source strengths and typical outdoor air contaminant concentrations, mass balance models were again used to calculate for each store the “IAQP” VR that would maintain indoor CoC concentrations below selected RELs. These IAQP VRs were compared to the observed VRs and to the Title 24- prescribed VRs. For the second goal, a VR intervention study was performed in the big box store to determine how objectively assessed indoor contaminant levels and subjectively assessed IAQ varied with VR. The three intervention study VRs included an approximation of the store’s current VR [0.24 air changes per hour (ACH)], the Title 24-prescribed VR [0.69 ACH], and the calculated IAQPbased VR [1.51 ACH]). Calculations of IAQP-based VRs showed that for the big box store and 11 of the 12 other stores, neither current measured VRs nor the Title 24-prescribed VRs would be sufficient to maintain indoor concentrations of all CoCs below RELs. In the intervention study, with the IAQP-based VR applied in the big box store, all CoCs were controlled below RELs (within margins of error). Also, at all three VRs in this store, the percentage of subjects reporting acceptable air quality exceeded an 80% criterion of acceptability. The IAQP allows consideration of outdoor air ventilation as just one of several possible tools for achieving adequate IAQ. In two of the 13 surveyed buildings, applying the IAQP to allow lower VRs could have saved energy whilst still maintaining acceptable indoor air quality. In the remaining 11 buildings, saving energy through lower VRs would require combination with other strategies, either reducing indoor sources of CoCs such as formaldehyde, or use of gas phase air cleaning technologies. Based on the findings from applying the IAQP calculations to retail stores and the IAQP-based intervention study, recommendations are made regarding the potential introduction of a comparable procedure in Title 24.« less

  8. On the importance of the heat and mass transfer resistances in internally-cooled liquid desiccant dehumidifiers and regenerators

    DOE PAGES

    Woods, Jason; Kozubal, Eric

    2018-02-06

    Liquid desiccant heat and mass exchangers are a promising technology for efficient humidity control in buildings. Many researchers have investigated these exchangers, often using numerical models to predict their performance. However, there is a lack of information in the literature on the magnitude of the heat and mass transfer resistances, both for the dehumidifier (which absorbs moisture from the air) and the regenerator (which heats the liquid desiccant to re-concentrate it). This article focuses on internally-cooled, 3-fluid exchangers in a parallel plate geometry. Water heats or cools a desiccant across a plate, and the desiccant absorbs or releases water intomore » an airstream through a membrane. A sensitivity analysis was used to estimate the importance of each of the heat and mass transfer resistances (air, membrane, desiccant, plate, water), and how it changes with different design geometries. The results show that, for most designs, the latent and sensible heat transfer of the dehumidifier is dominated by the air mass transfer resistance and air heat transfer resistance, respectively. The air mass transfer resistance is also important for the regenerator, but much less so; the change in the desiccant equilibrium humidity ratio due to a change in either temperature or desiccant mass fraction is much higher at the regenerator's higher temperatures. This increases the importance of (1) getting heat from the water to the desiccant/membrane interface, and (2) diffusing salt ions quickly away from the desiccant/membrane interface. The membrane heat transfer and water heat transfer resistances were found to be the least important. These results can help inform decisions about what simplifying assumptions to make in numerical models, and can also help in designing these exchangers by understanding which resistances are most important.« less

  9. Dehumidifier assisted drying of a model fruit pulp-based gel and sensory attributes.

    PubMed

    Tiwari, Shipra; Ravi, Ramasamy; Bhattacharya, Suvendu

    2012-07-01

    Model fruit pulp-based gels were prepared by varying mango pulp (0% to 50%), sucrose (0% to 20%), and agar (1% to 3%) and according to a response surface experimental design followed by drying at a low temperature of 40 °C upto 15 h in a tray dryer assisted by a dehumidifier. The moisture content, shrinkage (SHR), and rheological parameters (failure strain, failure stress (FS), firmness, and energy for compression) were determined as a function of drying time. The composition of gel, particularly the agar content had a prominent effect on the characteristics of the dried gel. Detailed descriptive sensory analysis employing principle component analysis (PCA) biplot indicated two distinct groups of attributes; the first group comprised initial and final moisture contents, extent of moisture removal (EMR), and shrinkage. The fracture stress and energy formed the second group. The analysis of variance for failure stress showed that it depended only on the positive linear and quadratic effects of agar (significant at P ≤ 0.01 and 0.05, respectively). The theoretically predicted extent of moisture removal at 95.6% could be achieved when the level of agar was 1.2%; pulp and sucrose levels were also close to their lowest levels of 3.6% and 0.04%, respectively. Scope exists to develop gel-based fruit analogues wherein an appropriate hydrocolloid can be employed along with fruit juice/pulp. To provide a reasonable shelf-life of the developed intermediate moisture containing product, dehumidifier assisted drying is a pragmatic approach that affects sensory and rheological attributes of the dried fruit analogue. © 2012 Institute of Food Technologists®

  10. Improving Comfort in Hot-Humid Climates with a Whole-House Dehumidifier, Windermere, Florida (Fact Sheet)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Not Available

    2013-11-01

    Maintaining comfort in a home can be challenging in hot-humid climates. At the common summer temperature set point of 75 degrees F, the perceived air temperature can vary by 11 degrees F because higher indoor humidity reduces comfort. Often the air conditioner (AC) thermostat set point is lower than the desirable cooling level to try to increase moisture removal so that the interior air is not humid or "muggy." However, this method is not always effective in maintaining indoor relative humidity (RH) or comfort. In order to quantify the performance of a combined whole-house dehumidifier (WHD) AC system, researchers frommore » the U.S. Department of Energy's Building America team Consortium of Advanced Residential Buildings (CARB) monitored the operation of two Lennox AC systems coupled with a Honeywell DH150 TrueDRY whole-house dehumidifier for a six-month period. By using a WHD to control moisture levels (latent cooling) and optimizing a central AC to control temperature (sensible cooling), improvements in comfort can be achieved while reducing utility costs. Indoor comfort for this study was defined as maintaining indoor conditions at below 60% RH and a humidity ratio of 0.012 lbm/lbm while at common dry bulb set point temperatures of 74 degrees -80 degrees F. In addition to enhanced comfort, controlling moisture to these levels can reduce the risk of other potential issues such as mold growth, pests, and building component degradation. Because a standard AC must also reduce dry bulb air temperature in order to remove moisture, a WHD is typically needed to support these latent loads when sensible heat removal is not desired.« less

  11. On the importance of the heat and mass transfer resistances in internally-cooled liquid desiccant dehumidifiers and regenerators

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Woods, Jason; Kozubal, Eric

    Liquid desiccant heat and mass exchangers are a promising technology for efficient humidity control in buildings. Many researchers have investigated these exchangers, often using numerical models to predict their performance. However, there is a lack of information in the literature on the magnitude of the heat and mass transfer resistances, both for the dehumidifier (which absorbs moisture from the air) and the regenerator (which heats the liquid desiccant to re-concentrate it). This article focuses on internally-cooled, 3-fluid exchangers in a parallel plate geometry. Water heats or cools a desiccant across a plate, and the desiccant absorbs or releases water intomore » an airstream through a membrane. A sensitivity analysis was used to estimate the importance of each of the heat and mass transfer resistances (air, membrane, desiccant, plate, water), and how it changes with different design geometries. The results show that, for most designs, the latent and sensible heat transfer of the dehumidifier is dominated by the air mass transfer resistance and air heat transfer resistance, respectively. The air mass transfer resistance is also important for the regenerator, but much less so; the change in the desiccant equilibrium humidity ratio due to a change in either temperature or desiccant mass fraction is much higher at the regenerator's higher temperatures. This increases the importance of (1) getting heat from the water to the desiccant/membrane interface, and (2) diffusing salt ions quickly away from the desiccant/membrane interface. The membrane heat transfer and water heat transfer resistances were found to be the least important. These results can help inform decisions about what simplifying assumptions to make in numerical models, and can also help in designing these exchangers by understanding which resistances are most important.« less

  12. 40 CFR 82.152 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...: compressor, condenser, evaporator, or auxiliary heat exchange coil; or any maintenance, service, or repair... in part or whole of a class I or class II ozone-depleting substance that is used for heat transfer... window air conditioners and packaged terminal air heat pumps), dehumidifiers, under-the-counter ice...

  13. Don`t sweat it, dehumidify

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Harriman, L.; Simkins, D.

    Beads of perspiration dripping from pipes and valves are a nuisance to mop up, but they are a telltale sign of the problems that excess humidity can cause. Fluctuations in the delicate balance of temperature and moisture in process environments are often the culprit for the corrosion, condensation, and clogging and sticking that bottlenecks plant operations and slows down production. Dehumidification is used to prevent moisture regain, condensation and corrosion, and to promote the drying of heat-sensitive products. There are three methods for removing moisture from air: Squeeze out water by increasing the pressure; though commonly used for compressed airmore » and other applications at elevated pressures, it is virtually never used to remove moisture in atmospheric pressure applications. Compressor equipment and operating costs are prohibitive, compared with those for conventional methods for dehumidifying air at ambient pressures; Condense water by chilling the surrounding air; and Pull out water by passing air across the surface of a desiccant. The paper discusses desiccation versus cooling, system design, and project management.« less

  14. Spirolit-2 instrument used to test pulmonary ventilation

    NASA Astrophysics Data System (ADS)

    Zhuravlev, V. V.

    1985-02-01

    At the present time, the Spirolit-2 automatic analyzer of main respiratory gases, of the Junkalor Dessau firm, is used to examine parameters of gas exchange, levels of energy expended by man and animals with different degrees of activity. However, the capabilities of this model of the instrument are limited. A method of determining pulmonary ventilation with use of the Spirolit-2 is described. An additional exhalation valve is built into a valve box to which an anesthesia machine rubber bag is attached. Samples are collected into another bag concurrently with the usual tests on the Spirolit-2 instrument. Four to five minutes are sufficient to obtain stable parameters at relative rest of oxygen uptake, determine carbon dioxide output per minute and collect samples in for analysis of exhaled air. The proposed method can furnish information about the dynamics of development of respiratory function of the lungs at virtually any moment with a constant physical load. For this, there must be spare bags to collect samples. Stage-by-stage data can be obtained analogously as to ventilation volume during a step test while determining maximum oxygen uptake.

  15. 49 CFR 173.307 - Exceptions for compressed gases.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    .... For transportation by air, tires and tire assemblies must meet the conditions in § 175.8(b)(4) of this subchapter. (3) Balls used for sports. (4) Refrigerating machines, including dehumidifiers and air conditioners, and components thereof, such as precharged tubing containing: (i) 12 kg (25 pounds) or less of a...

  16. 78 FR 31517 - Notification of Proposed Production Activity; Vestas Nacelles America, Inc.; Subzone 123E (Wind...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-24

    ... Activity; Vestas Nacelles America, Inc.; Subzone 123E (Wind Turbines); Brighton, Denver, Pueblo, and... during customs entry procedures that apply to wind turbines, nacelles, hubs, blades, and towers (free, 2...; dehumidifiers; cooling units; condensate heaters; heat exchangers; slip rings; filters; kabi sprayers; bearings...

  17. Effects of post-capture ventilation assistance and elevated water temperature on sockeye salmon in a simulated capture-and-release experiment

    PubMed Central

    Robinson, Kendra A.; Hinch, Scott G.; Gale, Marika K.; Clark, Timothy D.; Wilson, Samantha M.; Donaldson, Michael R.; Farrell, Anthony P.; Cooke, Steven J.; Patterson, David A.

    2013-01-01

    The live release of wild adult Pacific salmon (Oncorhynchus spp.) following capture is a management tactic often used in commercial, aboriginal, and recreational fisheries. Fisheries capture and handling can be both exhausting and stressful to fish, which can limit their ability to swim and survive after release. As a result, researchers have assessed methods intended to improve post-release survival by assisting the flow of water over the gills of fish prior to release. Such approaches use recovery bags or boxes that direct water over the gills of restrained fish. This study evaluated a method of assisting ventilation that mimics one often employed by recreational anglers (i.e. holding fish facing into a current). Under laboratory conditions, wild Fraser River sockeye salmon (Oncorhynchus nerka) either received manual ventilation assistance for 1 min using a jet of water focused at the mouth or were left to recover unassisted following a capture-and-release simulation. A control group consisted of fish that were not exposed to the simulation or ventilation assistance. The experiment was conducted at 16 and 21°C, average and peak summer water temperatures for the Fraser River, and fish survival was monitored for 33 days. At 21°C, all fish perished within 3 days after treatment in all experimental groups, highlighting the consequences of handling adult sockeye salmon during elevated migration temperatures. Survival was higher at 16°C, with fish surviving on average 15–20 days after treatment. At 16°C, the capture-and-release simulation and ventilation assistance did not affect the survival of males; however, female survival was poor after the ventilation assistance compared with the unassisted and control groups. Our results suggest that the method of ventilation assistance tested in this study may not enhance the post-release survival of adult Fraser River sockeye salmon migrating in fresh water. PMID:27293599

  18. 40. BUILDING NO. 454, ORDNANCE FACILITY (BAG CHANGE FILLING PLANT), ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    40. BUILDING NO. 454, ORDNANCE FACILITY (BAG CHANGE FILLING PLANT), DETAIL SOUTHEAST SIDE OF EXTERIOR ELECTRICAL EQUIPMENT ROOM, SHOWING DOOR TO SEWING ROOM NO. 3, VENTILATOR FAN (OVER DOOR), STEAM LINE (PIPE), SEWING MACHINE MOTOR IN OVERHEAD, ALARM BELL, EXPLOSION-PROOF SWITCH BOXES, GROUNDS ON DOORS, PULL ALARM HANDLE (EXTREME RIGHT; PULLEY CABLE CONDUCTED IN CONDUIT TO SWITCH INSIDE BUILDING. PULLEYS INSIDE ALL ELBOW JOINTS.) - Picatinny Arsenal, 400 Area, Gun Bag Loading District, State Route 15 near I-80, Dover, Morris County, NJ

  19. 77 FR 31443 - Energy Conservation Program: Test Procedures for Residential Dishwashers, Dehumidifiers, and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-25

    ... dishwashers with a separate soil- sensing cycle, and the normal cycle definition, power supply and detergent... Soiling Requirements 5. Detergent Dosing Specifications E. Incorporation by Reference of an Updated AHAM...: (1) The addition of a method to rate the efficiency of soil-sensing products; (2) the addition of a...

  20. 77 FR 76952 - Energy Conservation Program for Consumer Products: Association of Home Appliance Manufacturers...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-31

    ... conventional cooking products, published on October 31, 2012, and DOE's direct final rule to amend energy... cooking products (77 FR 65942 (Oct. 31, 2012)) and its direct final rule to amend the energy conservation... Residential Dishwashers, Dehumidifiers, and Conventional Cooking Products and Docket No. EERE-2011-BT-STD-0060...

  1. 49 CFR 571.103 - Standard No. 103; Windshield defrosting and defogging systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... concrete pavement (or other surface with equivalent coefficient of surface friction) at a specified speed... defogging system which operates either by applying heat to the windshield or by dehumidifying the air inside... equipped with a heating system other than a heat exchanger type that uses the engine's coolant as a means...

  2. 49 CFR 571.103 - Standard No. 103; Windshield defrosting and defogging systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... concrete pavement (or other surface with equivalent coefficient of surface friction) at a specified speed... defogging system which operates either by applying heat to the windshield or by dehumidifying the air inside... equipped with a heating system other than a heat exchanger type that uses the engine's coolant as a means...

  3. 49 CFR 571.103 - Standard No. 103; Windshield defrosting and defogging systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... concrete pavement (or other surface with equivalent coefficient of surface friction) at a specified speed... defogging system which operates either by applying heat to the windshield or by dehumidifying the air inside... equipped with a heating system other than a heat exchanger type that uses the engine's coolant as a means...

  4. Health-hazard evaluation report HETA 86-372-1796, National Marine Fisheries Service, US Department of Commerce, Pascagoula, Mississippi

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Boiano, J.M.; Cantor, F.L.; Burr, G.A.

    In response to a request from the U.S. Department of Commerce, an evaluation was made of an ongoing mold and mildew problem at the Southeastern Regional Office of the National Marine Fisheries Service located in Pascagoula, Mississippi. Office workers indicated they were suffering from throat irritation, itchy eyes, sneezing, and coughing symptoms. The problem was traced to an improperly installed all-water heating, ventilating, and air-conditioning system. Deficiencies in the system resulted in water damage, high humidity, and the growth of mold and mildew on all surfaces. Dehumidifiers were useful in reducing the humidity level, and therefore the growth of mildewmore » and mold, but there was still some visible contamination on room surfaces. Airborne levels of total viable microorganisms averaged 1,236 colony-forming units per cubic meter of air. The most-abundant fungal species isolated was Acremonium species. When the results of a medical questionnaire were compared to levels of fungal contamination there was no statistically significant association between the occurrence of illness and exposure to microorganisms. The authors recommend that insulation on the pipes and condenser drain lines be replaced to eliminate the moisture-incursion problems, that all nonporous surfaces be disinfected, and that all nondisposable building contents be cleaned with a vacuum incorporating a high-efficiency particulate air filter. Materials which could not be adequately cleaned were to be discarded.« less

  5. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rudd, A.

    This document covers a description of the need and applied solutions for supplemental dehumidification in warm-humid climates, especially for energy efficient homes where the sensible cooling load has been dramatically reduced. In older homes in warm-humid climates, cooling loads are typically high and cooling equipment runs a lot to cool the air. The cooling process also removes indoor moisture, reducing indoor relative humidity. However, at current residential code levels, and especially for above-code programs, sensible cooling loads have been so dramatically reduced that the cooling system does not run a lot to cool the air, resulting in much less moisturemore » being removed. In these new homes, cooling equipment is off for much longer periods of time especially during spring/fall seasons, summer shoulder months, rainy periods, some summer nights, and some winter days. In warm-humid climates, those long off periods allow indoor humidity to become elevated due to internally generated moisture and ventilation air change. Elevated indoor relative humidity impacts comfort, indoor air quality, and building material durability. Industry is responding with supplemental dehumidification options, but that effort is really in its infancy regarding year-round humidity control in low-energy homes. Available supplemental humidity control options are discussed. Some options are less expensive but may not control indoor humidity as well as more expensive and comprehensive options. The best performing option is one that avoids overcooling and avoids adding unnecessary heat to the space by using waste heat from the cooling system to reheat the cooled and dehumidified air to room-neutral temperature.« less

  6. Low-Flow Liquid Desiccant Air-Conditioning: Demonstrated Performance and Cost Implications

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kozubal, E.; Herrmann, L.; Deru, M.

    2014-09-01

    Cooling loads must be dramatically reduced when designing net-zero energy buildings or other highly efficient facilities. Advances in this area have focused primarily on reducing a building's sensible cooling loads by improving the envelope, integrating properly sized daylighting systems, adding exterior solar shading devices, and reducing internal heat gains. As sensible loads decrease, however, latent loads remain relatively constant, and thus become a greater fraction of the overall cooling requirement in highly efficient building designs, particularly in humid climates. This shift toward latent cooling is a challenge for heating, ventilation, and air-conditioning (HVAC) systems. Traditional systems typically dehumidify by firstmore » overcooling air below the dew-point temperature and then reheating it to an appropriate supply temperature, which requires an excessive amount of energy. Another dehumidification strategy incorporates solid desiccant rotors that remove water from air more efficiently; however, these systems are large and increase fan energy consumption due to the increased airside pressure drop of solid desiccant rotors. A third dehumidification strategy involves high flow liquid desiccant systems. These systems require a high maintenance separator to protect the air distribution system from corrosive desiccant droplet carryover and so are more commonly used in industrial applications and rarely in commercial buildings. Both solid desiccant systems and most high-flow liquid desiccant systems (if not internally cooled) add sensible energy which must later be removed to the air stream during dehumidification, through the release of sensible heat during the sorption process.« less

  7. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rudd, Armin

    This document covers a description of the need and applied solutions for supplemental dehumidification in warm-humid climates, especially for energy efficient homes where the sensible cooling load has been dramatically reduced. Cooling loads are typically high and cooling equipment runs a lot to cool the air in older homes in warm-humid climates. The cooling process also removes indoor moisture, reducing indoor relative humidity. However, at current residential code levels, and especially for above-code programs, sensible cooling loads have been so dramatically reduced that the cooling system does not run a lot to cool the air, resulting in much less moisturemore » being removed. In these new homes, cooling equipment is off for much longer periods of time especially during spring/fall seasons, summer shoulder months, rainy periods, some summer nights, and winter days. In warm-humid climates, those long-off periods allow indoor humidity to become elevated due to internally generated moisture and ventilation air change. Elevated indoor relative humidity impacts comfort, indoor air quality, and building material durability. Industry is responding with supplemental dehumidification options, but that effort is really in its infancy regarding year-round humidity control in low-energy homes. Available supplemental humidity control options are discussed. Some options are less expensive but may not control indoor humidity as well as more expensive and comprehensive options. The best performing option is one that avoids overcooling and adding unnecessary heat to the space by using waste heat from the cooling system to reheat the cooled and dehumidified air to room-neutral temperature.« less

  8. [Abdominal compartment syndrome by tension pneumoperitoneum secondary to barotrauma. Presentation case].

    PubMed

    García-Santos, Esther; Puerto-Puerto, Alejandro; Sánchez-García, Susana; Ruescas-García, Francisco Javier; Alberca-Páramo, Ana; Martín-Fernández, Jesús

    2015-01-01

    Pneumoperitoneum is defined as the existence of extraluminal air in the abdominal cavity. In 80-90% of cases is due to perforation of a hollow organ. However, in 10-15% of cases, it is nonsurgical pneumoperitoneum. The case of a patient undergoing mechanical ventilation, developing abdominal compartment syndrome tension pneumoperitoneum is reported. Female, 75 years old asking for advise due to flu of long term duration. Given her respiratory instability, admission to the Intensive Care Unit is decided. It is then intubated and mechanically ventilated. Chest x-ray revealed a large pneumoperitoneum but no pneumothorax neither mediastinum; and due to the suspicion of viscera perforation with clinical instability secondary to intra-abdominal hypertension box, emergency surgery was decided. When discarded medical history as a cause of pneumoperitoneum, it is considered that ventilation is the most common cause. Benign idiopathic or nonsurgical pneumoperitoneum, can be be treated conservatively if the patient agrees. But if intraabdominal hypertension prevails, it can result in severe respiratory and hemodynamic deterioration, sometimes requiring abdominal decompression to immediately get lower abdominal pressure and thus improve hemodynamic function. Copyright © 2015 Academia Mexicana de Cirugía A.C. Published by Masson Doyma México S.A. All rights reserved.

  9. 77 FR 51943 - Energy Conservation Standards for Residential Dehumidifiers: Public Meeting and Availability of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-28

    ...) 586-2945. Please submit one signed original paper copy. Hand Delivery/Courier: Ms. Brenda Edwards, U.S.... Please submit one signed original paper copy. Docket: For access to the docket to read background... the comment period should extend past the public meeting date. DOE has determined that an extension of...

  10. 49 CFR 571.103 - Standard No. 103; Windshield defrosting and defogging systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... concrete pavement (or other surface with equivalent coefficient of surface friction) at a specified speed... defogging system which operates either by applying heat to the windshield or by dehumidifying the air inside... system other than a heat exchanger type that uses the engine's coolant as a means to supply the heat to...

  11. 49 CFR 571.103 - Standard No. 103; Windshield defrosting and defogging systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... concrete pavement (or other surface with equivalent coefficient of surface friction) at a specified speed... defogging system which operates either by applying heat to the windshield or by dehumidifying the air inside... system other than a heat exchanger type that uses the engine's coolant as a means to supply the heat to...

  12. A Mold by Any Other Name: One Librarian's Battle Against a Mold Bloom.

    ERIC Educational Resources Information Center

    Smith, Laura Katz

    1997-01-01

    Describes how library staff at Virginia Polytechnic Institute and State University cleaned up materials after a mold bloom in the rare book room. Includes advice for controlling mold: set up a hygrothermograph, clean dust from books, set up fans, do a "skin" test at regular intervals, keep windows closed, have dehumidifiers available.…

  13. Déshumidification de l'air d'une serre par contact direct à courants croisés avec une solution hygroscopique organique

    NASA Astrophysics Data System (ADS)

    Chraibi, A.; Jaffrin, A.; Makhlouf, S.; Bentounes, N.

    1995-07-01

    Greenhouse air can be dehumidified by direct contact with a desicant fluid on a trickle exchanger. The water vapour extraction rate depends on the hygroscopicity of the fluid and on the exchanger efficiency. An organic fluid, the triethylene glycol (TEG) at 90% concentration, has been tested. Cross corrugated cellulosic pads, of the type used in cooling, irrigated with TEG, were placed in a wind channel to dehumidify air at various speeds and temperatures. A semi-analytical model, based on energy and mass conservation, correctly reproduces the water vapor extraction rate and the enthalpy change of both fluids. It is shown that TEG trickling through a ventilated pad of 1 m^2 area and 0.1 m thickness can be used to extract 3 to 5 kg of water vapor per hour in greenhouse climate control applications. Several pads arranged in series can be used to decrease more efficiently the absolute humidity of the air, for other applications like food drying or industrial compressed air. Une technique de déshumidification de l'air des serres consiste à le soumettre au contact d'une solution hygroscopique au sein d'un échangeur ruisselant. Le taux d'extraction de vapeur d'eau dépend à la fois du pouvoir hygroscopique de la solution et de l'efficacité de l'échangeur. Une solution hygroscopique organique, le triéthylène glycol à 90% de concentration, a été expérimentée. Un échangeur ruisselant constitué de parois de cellulose ondulées à corrugations croisées, du type “cooling pad” pour serres agricoles, a été testé pour déshumidifier de l'air dans une soufflerie expérimentale. Un modèle semi-analytique, basé sur les équations de conservation de l'énergie et de masse, permet de rendre compte des échanges et de déduire les paramètres de sortie des deux fluides en contact, à partir des caractéristiques d'entrée. Cette étude permet de chiffrer à environ 3 à 5kg/h la capacité de déshumidification d'un panneau d'un mètre carré et de 10cm d'épaisseur opérant dans les conditions d'une serre agricole. L'usage de plusieurs panneaux en série permettrait d'abaisser plus fortement l'hygrométrie de l'air traité pour d'autres applications, telles que le séchage de plantes aromatiques ou de l'air comprimé dans l'industrie.

  14. Effects of cisatracurium in combination with ventilation on inflammatory factors and immune variations in sepsis rats.

    PubMed

    He, Tongyun; Tao, Jianmei; Wang, Xinqiang; Wang, Xuena

    2018-05-01

    The effects of cisatracurium in combination with ventilation on inflammatory factors and immune variations in sepsis rats were investigated. A total of 54 male Sprague-Dawley rats were selected and divided randomly into three groups: Sham group (n=6), model group (n=24) and experiment group (n=24). Rats in the model and experiment groups underwent cecal ligation and puncture (CLP) for establishment of sepsis model. Rats in experiment group additionally received cisatracurium medication in combination with ventilation for treatment. At 6, 12 and 24 h after CLP, the levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6 and procalcitonin (PCT) in serum and the ratio of leukocyte to neutrophil in peripheral blood was also detected. Twenty-four hours later, the expression of high mobility group box 1 (HMGB1) in lung tissues and cluster of differentiation (CD) 4 + and CD8 + in T-lymphocyte subsets were also detected, and the wet/dry (W/D) ratio of lung was measured. Compared with that in model group, the levels of inflammatory factors in the experiment group were significantly decreased, while the indicators in assays of cellular immunity were obviously elevated. Ratio of leukocyte to neutrophil in peripheral blood was significantly decreased after treatment. Cisatracurium in combination with ventilation can alleviate the inflammatory injury to organs in sepsis rats through inhibiting the inflammatory responses and regulating the immune functions, which manifests a new significance in guiding the clinical diagnosis and treatment.

  15. Water vapor mass balance method for determining air infiltration rates in houses

    Treesearch

    David R. DeWalle; Gordon M. Heisler

    1980-01-01

    A water vapor mass balance technique that includes the use of common humidity-control equipment can be used to determine average air infiltration rates in buildings. Only measurements of the humidity inside and outside the home, the mass of vapor exchanged by a humidifier/dehumidifier, and the volume of interior air space are needed. This method gives results that...

  16. USAF Dehumidification Efforts for Corrosion Control

    DTIC Science & Technology

    2011-08-16

    Stored AGE Renewable energy powers dehumidification equipment (DH) DH maintains dry air in storage booths, protecting AGE equipment from...lighting also powered by renewable energy 11 CHP Shelters • Used to prevent corrosion on outer skin • Being developed for the F-22 at...DH can be Sheltered or Unsheltered • Air Dehydration Units - Uses a self rejuvenating desiccant wheel dehumidifier - Closed or open loop

  17. Specialized physiological studies in support of manned space flight

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Breath-by-breath measurements of pulmonary capillary O2 transfer and ventilation with a box-balloon spirometer and mass spectrometer were made on 3 subjects before, during and after 10 min of lower body negative pressure (LBNP) at -20, -40 and -60 Torr with arterial samples at -60 Torr. Deficits in blood O2 stores (O2B) were noted during LBNP with repayment of O2B during recovery being related to the intensity of LBNP stress. Concurrent calf volume, measured with a Hg strain gauge, decreased towards baseline well before the peak rise in pulmonary capillary O2 transfer after the release of LBNP which signified that O2B changes were related to blood volume shifts. The return of O2-depleted pooled blood to the central circulation during the first min. of recovery caused significant stress-related hyperpnea which peaked near 30 sec. and returned to near baseline after the first min. Three-compartment lung model analyses indicated an increase in the ventilated unperfused lung fraction from 0.09 to 0.17 with the effective compartment decreasing from 0.83 to 0.77. It appears that the 30% increase in ventilation equivalent was primarily the result of less effective lung perfusion during the LBNP.

  18. Energy metabolism during activity-promoting video games practice in subjects with spinal cord injury: evidences for health promotion.

    PubMed

    Gaffurini, P; Bissolotti, L; Calza, S; Calabretto, C; Orizio, C; Gobbo, M

    2013-02-01

    Activity promoting video game (APVG) practice significantly affects energy metabolism through energy expenditure (EE) increase and has been recently included in strategies for health promotion. It is not known if the APVG practice provides similar outcomes in subjects with spinal cord injury (SCI). Aim of the study was to evaluate cardio-pulmonary and metabolic adaptations during APVG practice and to find whether EE increase above resting condition could suggest the inclusion of this exercise in a more general strategy for health promotion and body weight control in subjects with SCI. Repeated measures study. Rehabilitation Institute. Ten male subjects with SCI (lesion levels from C7 to L1) age 26 to 55 years. We recorded pulmonary ventilation (VE), oxygen consumption (VO2) for EE esteem and heart rate (HR) at rest and while playing virtual bowling, tennis and boxing games using a portable metabolimeter equipped with ECG electrodes. The standard metabolic equivalent of task (METs) was calculated offline. The metabolic and functional parameters were referred to the 10th minute of each activity. Metabolic and functional parameters increased significantly from rest to bowling, tennis and boxing. METs exceeded in average 3 during boxing. One hour of APVG can increase daily EE by about 6% (bowling), 10% (tennis) and 15% (boxing). These considerable results suggest that physical exertion during APVG practice in subjects with SCI could contribute to health promotion as well as caloric balance control, especially when boxing is considered. This can be safely achieved at home with regular activity. These findings substantiate the potential for novel exercise modalities to counteract deconditioning due to inactivity in subjects with SCI by promoting physical activity through implementation of APVG exercise programs.

  19. Reliability-Centered Maintenance

    DTIC Science & Technology

    1978-12-29

    the pack through a flow-control valve and is cooled and dehumidified by a heat exchanger and the turbine of an air-cycle refrigeration ma- chine. The...dirt, moisture, and heat are the most susceptible to corrosion, and properly applied and maintained protective coatings are necessary to prevent...LFM’TNT i RCJL, ’A~r I ARLCA & WORK JNI- N UMUL R, United Airlines San Francisco International Airport San Francisco, Ca 94128 Office of Assistant

  20. Effects of steam-microwave blanching and different drying processes on drying characteristics and quality attributes of Thunbergia laurifolia Linn. leaves.

    PubMed

    Phahom, Traiphop; Phoungchandang, Singhanat; Kerr, William L

    2017-08-01

    Dried Thunbergia laurifolia leaves are usually prepared using tray drying, resulting in products that have lost substantial amounts of bioactive compounds and antioxidant activity. The maturity of the raw material, blanching techniques and drying methods were investigated in order to select the best condition to produce high qualities of dried T. laurifolia leaves. The 1st stage of maturity was selected and steam-microwave blanching (SMB) for 4 min was adequate for blanching leading to the maximum recovery of bioactive compounds. The modified Halsey model was the best desorption isotherm model. A new drying model proposed in this study was the best to fit the drying curves as compared to five common drying models. Moisture diffusivities were increased with the increase of drying temperature when combining SMB and heat pump-dehumidified drying. Microwave heat pump-dehumidified drying (MHPD) provided the shortest drying time, high specific moisture extraction rate (SMER) and could reduce drying time by 67.5% and increase caffeic acid and quercetin by 51.24% and 60.89%, respectively. MHPD was found to be the best drying method and provided the highest antioxidant activity and bioactive compounds content, high SMER and short drying time. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  1. Preparing cytotoxic agents in an isolator.

    PubMed

    Favier, M; Hansel, S; Bressolle, F

    1993-11-01

    The design of an isolator and its use by an oncology satellite pharmacy for preparing cytotoxic drugs are described. The isolator (Iso Concept, Boulogne, France) is a totally enclosed ventilated biological-safety cabinet of class III polyvinyl chloride (PVC) with positive air pressure, a half-suit with a rotating seal, and attached neoprene gloves. There are three work-stations, one for the half-suit and two along one side of the isolator. The ventilation and air filtration system consists of one entry pipe with a full ventilation-filtration box fitted with one prefilter, one blower, one ball valve, one high-efficiency particulate air (HEPA) filter, one airtight nipple connected to an automatic sterilizer, alarms, and one exhaust pipe protected by a HEPA filter. The air lock consists of a rigid, transparent Plexiglas pass-through. The chamber is sterilized with heated compressed air mixed with 3.5% peracetic acid. Maintenance includes regular changing of gloves and HEPA filters; checking of the integrity of the PVC, half-suit, and gloves; and washing and decontamination procedures. Preparation of cytotoxics is planned in advance with prescription data and manufacturing sheets. In the half-suit, a pharmacy technician reads the label, supervises preparation of the sterile admixture, and writes a label. The operators on the side of the unit read the manufacturing sheet and prepare the dose identified by the label.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. A simple method for isocapnic hyperventilation evaluated in a lung model.

    PubMed

    Hallén, K; Stenqvist, O; Ricksten, S-E; Lindgren, S

    2016-05-01

    Isocapnic hyperventilation (IHV) has the potential to increase the elimination rate of anaesthetic gases and has been shown to shorten time to wake-up and post-operative recovery time after inhalation anaesthesia. In this bench test, we describe a technique to achieve isocapnia during hyperventilation (HV) by adding carbon dioxide (CO2) directly to the breathing circuit of a standard anaesthesia apparatus with standard monitoring equipment. Into a mechanical lung model, carbon dioxide was added to simulate a CO2 production (V(CO2)) of 175, 200 and 225 ml/min. Dead space (V(D)) volume could be set at 44, 92 and 134 ml. From baseline ventilation (BLV), HV was achieved by doubling the minute ventilation and fresh gas flow for each level of V(CO2), and dead space. During HV, CO2 was delivered (D(CO2)) by a precision flow meter via a mixing box to the inspiratory limb of the anaesthesia circuit to achieve isocapnia. During HV, the alveolar ventilation increased by 113 ± 6%. Tidal volume increased by 20 ± 0.1% during IHV irrespective of V(D) and V(CO2) level. D(CO2) varied between 147 ± 8 and 325 ± 13 ml/min. Low V(CO2) and large V(D) demanded a greater D(CO2) administration to achieve isocapnia. The FICO2 level during IHV varied between 2.3% and 3.3%. It is possible to maintain isocapnia during HV by delivering carbon dioxide through a standard anaesthesia circuit equipped with modern monitoring capacities. From alveolar ventilation, CO2 production and dead space, the amount of carbon dioxide that is needed to achieve IHV can be estimated. © 2015 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  3. Decommissioning of Active Ventilation Systems in a Nuclear R and D Facility to Prepare for Building Demolition (Whiteshell Laboratories Decommissioning Project, Canada) - 13073

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wilcox, Brian; May, Doug; Howlett, Don

    2013-07-01

    Whiteshell Laboratories (WL) is a nuclear research establishment owned by the Canadian government and operated by Atomic Energy of Canada Limited (AECL) since the early 1960's. WL is currently under a decommissioning license and the mandate is to remediate the nuclear legacy liabilities in a safe and cost effective manner. The WL Project is the first major nuclear decommissioning project in Canada. A major initiative underway is to decommission and demolish the main R and D Laboratory complex. The Building 300 R and D complex was constructed to accommodate laboratories and offices which were mainly used for research and developmentmore » associated with organic-cooled reactors, nuclear fuel waste management, reactor safety, advanced fuel cycles and other applications of nuclear energy. Building 300 is a three storey structure of approximately 16,000 m{sup 2}. In order to proceed with building demolition, the contaminated systems inside the building have to be characterized, removed, and the waste managed. There is a significant focus on volume reduction of radioactive waste for the WL project. The active ventilation system is one of the significant contaminated systems in Building 300 that requires decommissioning and removal. The active ventilation system was designed to manage hazardous fumes and radioactivity from ventilation devices (e.g., fume hoods, snorkels and glove boxes) and to prevent the escape of airborne hazardous material outside of the laboratory boundary in the event of an upset condition. The system includes over 200 ventilation devices and 32 active exhaust fan units and high efficiency particulate air (HEPA) filters. The strategy to remove the ventilation system was to work from the laboratory end back to the fan/filter system. Each ventilation duct was radiologically characterized. Fogging was used to minimize loose contamination. Sections of the duct were removed by various cutting methods and bagged for temporary storage prior to disposition. Maintenance of building heating, ventilation and air conditioning (HVAC) balancing was critical to ensure proper airflow and worker safety. Approximately 103 m{sup 3} of equipment and materials were recovered or generated by the project. Low level waste accounted for approximately 37.4 m{sup 3}. Where possible, ducting was free released for metal recycling. Contaminated ducts were compacted into B-1000 containers and stored in a Shielded Modular Above-Ground Storage Facility (SMAGS) on the WL site awaiting final disposition. The project is divided into three significant phases, with Phases 1 and 2 completed. Lessons learned during the execution of Phases 1 and 2 have been incorporated into the current ventilation removal. (authors)« less

  4. 47. View of "dry air inlets" to waveguides entering scanner ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    47. View of "dry air inlets" to waveguides entering scanner building 105. Dried air is generated under pressure by Ingersoll-Rand dehumidified/dessicator and compressor system. View is at entrance from passageway that links into corner of scanner building. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

  5. Solid oxide fuel cell/gas turbine trigeneration system for marine applications

    NASA Astrophysics Data System (ADS)

    Tse, Lawrence Kar Chung; Wilkins, Steven; McGlashan, Niall; Urban, Bernhard; Martinez-Botas, Ricardo

    2011-03-01

    Shipping contributes 4.5% to global CO2 emissions and is not covered by the Kyoto Agreement. One method of reducing CO2 emissions on land is combined cooling heating and power (CCHP) or trigeneration, with typical combined thermal efficiencies of over 80%. Large luxury yachts are seen as an ideal entry point to the off-shore market for this developing technology considering its current high cost. This paper investigates the feasibility of combining a SOFC-GT system and an absorption heat pump (AHP) in a trigeneration system to drive the heating ventilation and air conditioning (HVAC) and electrical base-load systems. A thermodynamic model is used to simulate the system, with various configurations and cooling loads. Measurement of actual yacht performance data forms the basis of this system simulation. It is found that for the optimum configuration using a double effect absorption chiller in Ship 1, the net electric power increases by 47% relative to the electrical power available for a conventional SOFC-GT-HVAC system. This is due to more air cooled to a lower temperature by absorption cooling; hence less electrical cooling by the conventional HVAC unit is required. The overall efficiency is 12.1% for the conventional system, 34.9% for the system with BROAD single effect absorption chiller, 43.2% for the system with double effect absorption chiller. This shows that the overall efficiency of a trigeneration system is far higher when waste heat recovery happens. The desiccant wheel hardly reduces moisture from the outdoor air due to a relative low mass flow rate of fuel cell exhaust available to dehumidify a very large mass flow rate of HVAC air, Hence, desiccant wheel is not recommended for this application.

  6. Electromechanical Nerve Stimulator

    NASA Technical Reports Server (NTRS)

    Tcheng, Ping; Supplee, Frank H., Jr.; Prass, Richard L.

    1993-01-01

    Nerve stimulator applies and/or measures precisely controlled force and/or displacement to nerve so response of nerve measured. Consists of three major components connected in tandem: miniature probe with spherical tip; transducer; and actuator. Probe applies force to nerve, transducer measures force and sends feedback signal to control circuitry, and actuator positions force transducer and probe. Separate box houses control circuits and panel. Operator uses panel to select operating mode and parameters. Stimulator used in research to characterize behavior of nerve under various conditions of temperature, anesthesia, ventilation, and prior damage to nerve. Also used clinically to assess damage to nerve from disease or accident and to monitor response of nerve during surgery.

  7. [United Plackett-Burman and Box-Behnken design to control formation of indirubin in process of preparing indigo naturalis].

    PubMed

    Liu, Zeyu; Su, Zhetong; Yang, Ming; Zou, Wenquan

    2010-10-01

    To screen the factors that affect indirubin-generated significantly in the process of preparing indigo naturalis, optimize level combination and determine the optimum technology for indirubin-generated. Using concentration of indirubin (mg x g(-1)) that generated by fresh leaf as an index, Plackett-Burman design, Box-Behnken design response surface analysis as the statistical method, we screened the significantly influencing factors and the optimal level combination. The soaking and making indirubin process in preparing indigo naturalis was identified as the wax is not removed before immersion with immersion pH 7, solvent volume-leaf weight (mL: g)15, soaked not avoided light, soaking 48 h, temperature 60 degrees C, ventilation time of 180 min, and added ammonia water to adjust pH to 10.5. The soaking and making indirubin process in preparing indigo naturalis is optimized systematically. It clarify the various factors on the impact of the active ingredient indirubin which controlled by industrialized production become reality in the process of preparing indigo naturalis, at the same time, it lay the foundation for processing principle of indigo naturalis.

  8. Use of a double condenser in a dehumidifier with a spray dryer for vitamin A extraction in tomato as a heat-sensitive material

    NASA Astrophysics Data System (ADS)

    Kosasih, E. A.; Warjito, H., Imansyah I.; Ruhyat, N.

    2017-06-01

    Spray dryers are commonly operated at a high temperature (>100 °C), which becomes an obstacle for heat-sensitive materials. In this study, a refrigeration system that uses evaporator as dehumidifier and that recovers the heat released from the first condenser to preheat the drying air was utilised to reduce the drying temperature. Results showed that the degradation of vitamin A (measured with the high performance liquid chromatography method) in tomato increased significantly when the drying air temperature increased from 90 °C to 120 °C, and it cannot be controlled at a temperature higher than 120 °C. At an air flow rate of 450 lpm, the drying capacity at a drying air temperature of 60 °C (with refrigeration, humidity ratio of 0.005 [kg H2O / kg dry air]) is equal to the drying capacity at a drying air temperature of 120 °C (without refrigeration, humidity ratio of 0.021 [kg H2O / kg dry air]). The drying capacity at a drying air temperature of 90 °C (with refrigeration) even becomes 1.5 times the drying capacity at a drying air temperature of 120 °C (without refrigeration). The combination of a spray dryer system with a refrigeration system (double condenser) is therefore beneficial for drying heat-sensitive materials, such as vitamin A.

  9. Comparison of two different types of heat and moisture exchangers in ventilated patients.

    PubMed

    Ahmed, Syed Moied; Mahajan, Jyotsna; Nadeem, Abu

    2009-09-01

    To compare the efficacy of two different types of Heat and Moisture Exchangers (HME filters) in reducing transmission of infection from the patient to ventilator and vice versa and also its cost effectiveness. Randomized, controlled, double blind, prospective study. 60 patients admitted to the ICU from May 1, 2007 to July 31, 2007 of either sex, age ranging between 20 and 60 years, requiring mechanical ventilation were screened for the study. Following intubation of the patients, the HME device was attached to the breathing circuit randomly by the chit-in-a box method. The patients were divided into two groups according to the HME filters attached. Both the groups were comparable with respect to age and sex ratio. In Type A HME filters, 80% showed growth on the patient end within 24 h and in 27% filters, culture was positive both on the patient and the machine ends. The organisms detected were Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa and co-related with the endotracheal aspirate culture. After 48 h, 87% filters developed organisms on the patient end, whereas 64% filters were culture positive both on the patient and the machine end. In Type B HME filters, 70% showed growth on patient's end after 24 h. Organisms detected were S. aureus, E. coli, P. aeruginosa and Acinetobacter. Thirty percent of filters were culture negative on both the patient and machine ends. No growth was found on the machine end in any of the filters after 24 h. After 48 h, 73% of the filters had microbial growth on the patient end, whereas only 3% filters had growth (S. aureus) on the machine end only. Seven percent had growth on both the patient as well as the machine ends. The microorganisms detected on the HME filters co-related with the endotracheal aspirate cultures. HME filter Type B (study group) was significantly better in reducing contamination of ventilator from the patient as compared to Type A (control group), which was routinely used in our ICU. Type B filter was found to be effective for at least 48 h. This study can also be applied to patients coming to emergency department (ED) and requiring emergency surgery and postoperative ventilation; and trauma patients like flail chest, head injury etc. requiring ventilatory support to prevent them from acquiring ventilator-associated pneumonia (VAP).

  10. The Competition Between a Localised and Distributed Source of Buoyancy

    NASA Astrophysics Data System (ADS)

    Partridge, Jamie; Linden, Paul

    2012-11-01

    We propose a new mathematical model to study the competition between localised and distributed sources of buoyancy within a naturally ventilated filling box. The main controlling parameters in this configuration are the buoyancy fluxes of the distributed and local source, specifically their ratio Ψ. The steady state dynamics of the flow are heavily dependent on this parameter. For large Ψ, where the distributed source dominates, we find the space becomes well mixed as expected if driven by an distributed source alone. Conversely, for small Ψ we find the space reaches a stable two layer stratification. This is analogous to the classical case of a purely local source but here the lower layer is buoyant compared to the ambient, due to the constant flux of buoyancy emanating from the distributed source. The ventilation flow rate, buoyancy of the layers and also the location of the interface height, which separates the two layer stratification, are obtainable from the model. To validate the theoretical model, small scale laboratory experiments were carried out. Water was used as the working medium with buoyancy being driven directly by temperature differences. Theoretical results were compared with experimental data and overall good agreement was found. A CASE award project with Arup.

  11. The simulation of temperature distribution and relative humidity with liquid concentration of 50% using computational fluid dynamics

    NASA Astrophysics Data System (ADS)

    Yohana, Eflita; Yulianto, Mohamad Endy; Kwang-Hwang, Choi; Putro, Bondantio; Yohanes Aditya W., A.

    2015-12-01

    The study of humidity distribution simulation inside a room has been widely conducted by using computational fluid dynamics (CFD). Here, the simulation was done by employing inputs in the experiment of air humidity reduction in a sample house. Liquid dessicant CaCl2was used in this study to absorb humidity in the air, so that the enormity of humidity reduction occured during the experiment could be obtained.The experiment was conducted in the morning at 8 with liquid desiccant concentration of 50%, nozzle dimension of 0.2 mms attached in dehumidifier, and the debit of air which entered the sample house was 2.35 m3/min. Both in inlet and outlet sides of the room, a DHT 11 censor was installed and used to note changes in humidity and temperature during the experiment. In normal condition without turning on the dehumidifier, the censor noted that the average temperature inside the room was 28°C and RH of 65%.The experiment result showed that the relative humidity inside a sample house was decreasing up to 52% in inlet position. Further, through the results obtained from CFD simulation, the temperature distribution and relative humidity inside the sample house could be seen. It showed that the concentration of liquid desiccant of 50% experienced a decrease while the relative humidity distribution was considerably good since the average RH was 55% followed by the increase in air temperature of 29.2° C inside the sample house.

  12. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Not Available

    This report, Evaluation of the Performance of Houses with and without Supplemental Dehumidification in a Hot-Humid Climate, describes a research study that that was conducted by the Building Science Corporation (BSC) Building America Research Team. BSC seeks to research and report on the field monitoring of the performance of in-situ supplemental dehumidification systems in low energy, high performance, homes in a Hot-Humid climate. The purpose of this research project was to observe and compare the humidity control performance of new, single family, low energy, and high performance, homes. Specifically, the study sought to compare the interior conditions and mechanical systemsmore » operation between two distinct groups of houses, homes with a supplemental dehumidifier installed in addition to HVAC system, and homes without any supplemental dehumidification. The subjects of the study were ten single-family new construction homes in New Orleans, LA. Data logging equipment was installed at each home in 2012. Interior conditions and various end-use loads were monitored for one year. In terms of averages, the homes with dehumidifiers are limiting elevated levels of humidity in the living space. However, there was significant variation in humidity control between individual houses. An analysis of the equipment operation did not show a clear correlation between energy use and humidity levels. In general, no single explanatory variable appears to provide a consistent understanding of the humidity control in each house. Indoor humidity is likely due to all of the factors we have examined, and the specifics of how they are used by each occupant.« less

  13. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kerrigan, P.; Norton, P.

    This report, Evaluation of the Performance of Houses with and without Supplemental Dehumidification in a Hot-Humid Climate, describes a research study that that was conducted by the Building Science Corporation (BSC) Building America Research Team. BSC seeks to research and report on the field monitoring of the performance of in-situ supplemental dehumidification systems in low energy, high performance, homes in a Hot-Humid climate. The purpose of this research project was to observe and compare the humidity control performance of new, single family, low energy, and high performance, homes. Specifically, the study sought to compare the interior conditions and mechanical systemsmore » operation between two distinct groups of houses, homes with a supplemental dehumidifier installed in addition to HVAC system, and homes without any supplemental dehumidification. The subjects of the study were ten single-family new construction homes in New Orleans, LA.Data logging equipment was installed at each home in 2012. Interior conditions and various end-use loads were monitored for one year. In terms of averages, the homes with dehumidifiers are limiting elevated levels of humidity in the living space. However, there was significant variation in humidity control between individual houses. An analysis of the equipment operation did not show a clear correlation between energy use and humidity levels. In general, no single explanatory variable appears to provide a consistent understanding of the humidity control in each house. Indoor humidity is likely due to all of the factors we have examined, and the specifics of how they are used by each occupant.« less

  14. Minimum airflow reset of single-duct VAV terminal boxes

    NASA Astrophysics Data System (ADS)

    Cho, Young-Hum

    Single duct Variable Air Volume (VAV) systems are currently the most widely used type of HVAC system in the United States. When installing such a system, it is critical to determine the minimum airflow set point of the terminal box, as an optimally selected set point will improve the level of thermal comfort and indoor air quality (IAQ) while at the same time lower overall energy costs. In principle, this minimum rate should be calculated according to the minimum ventilation requirement based on ASHRAE standard 62.1 and maximum heating load of the zone. Several factors must be carefully considered when calculating this minimum rate. Terminal boxes with conventional control sequences may result in occupant discomfort and energy waste. If the minimum rate of airflow is set too high, the AHUs will consume excess fan power, and the terminal boxes may cause significant simultaneous room heating and cooling. At the same time, a rate that is too low will result in poor air circulation and indoor air quality in the air-conditioned space. Currently, many scholars are investigating how to change the algorithm of the advanced VAV terminal box controller without retrofitting. Some of these controllers have been found to effectively improve thermal comfort, indoor air quality, and energy efficiency. However, minimum airflow set points have not yet been identified, nor has controller performance been verified in confirmed studies. In this study, control algorithms were developed that automatically identify and reset terminal box minimum airflow set points, thereby improving indoor air quality and thermal comfort levels, and reducing the overall rate of energy consumption. A theoretical analysis of the optimal minimum airflow and discharge air temperature was performed to identify the potential energy benefits of resetting the terminal box minimum airflow set points. Applicable control algorithms for calculating the ideal values for the minimum airflow reset were developed and applied to actual systems for performance validation. The results of the theoretical analysis, numeric simulations, and experiments show that the optimal control algorithms can automatically identify the minimum rate of heating airflow under actual working conditions. Improved control helps to stabilize room air temperatures. The vertical difference in the room air temperature was lower than the comfort value. Measurements of room CO2 levels indicate that when the minimum airflow set point was reduced it did not adversely affect the indoor air quality. According to the measured energy results, optimal control algorithms give a lower rate of reheating energy consumption than conventional controls.

  15. MS Grunsfeld and Linnehan on middeck after EVA 1

    NASA Image and Video Library

    2002-03-04

    STS109-349-027 (4 March 2002) --- Astronauts John M. Grunsfeld and Richard M. Linnehan, STS-109 payload commander and mission specialist, respectively, wearing the liquid cooling and ventilation garment that complements the Extravehicular Mobility Unit (EMU) space suit, are photographed on the mid deck of the Space Shuttle Columbia after the mission’s first session of extravehicular activity (EVA). The EVA-1 team replaced one of the telescope’s two second-generation solar arrays, which is also known as SA2, and a Diode Box Assembly. The solar array was replaced with a new, third-generation solar array, which is called SA3. The space walkers also did some prep work for STS-109’s other space walks.

  16. Whole-Home Dehumidifiers: Field-Monitoring Study

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Burke, Tom; Willem, Henry; Ni, Chun Chun

    2014-09-23

    Lawrence Berkeley National Laboratory (LBNL) initiated a WHD field-metering study to expand current knowledge of and obtain data on WHD operation and energy consumption in real-world applications. The field study collected real-time data on WHD energy consumption, along with information regarding housing characteristics, consumer behavior, and various outdoor conditions expected to affect WHD performance and efficiency. Although the metering study collected similar data regarding air conditioner operation, this report discusses only WHDs. The primary objectives of the LBNL field-metering study are to (1) expand knowledge of the configurations, energy consumption profiles, consumer patterns of use (e.g., relative humidity [RH] settings),more » and environmental parameters of whole-home dehumidification systems; and (2) develop distributions of hours of dehumidifier operation in four operating modes: off, standby, fan-only, and compressor (also called dehumidification mode). Profiling energy consumption entails documenting the power consumption, duration of power consumption in different modes, condensate generation, and properties of output air of an installed system under field conditions of varying inlet air temperature and RH, as well as system configuration. This profiling provides a more detailed and deeper understanding of WHD operation and its complexities. This report describes LBNL’s whole-home dehumidification field-metering study conducted at four homes in Wisconsin and Florida. The initial phase of the WHD field-metering study was conducted on one home in Madison, Wisconsin, from June to December of 2013. During a second phase, three Florida homes were metered from June to October of 2014. This report presents and examines data from the Wisconsin site and from the three Florida sites.« less

  17. Software for the Design of Swimming Pool Dehumidifiers Units

    NASA Astrophysics Data System (ADS)

    Rubina, Aleš; Blasinski, Petr; Tesař, Zdeněk

    2013-06-01

    The article deals with the description and solution of physical phenomena taking place during evaporation of water. The topicality of the theme is given a number of built indoor swimming pool and wellness centers at present. In addressing HVAC systems serving these areas, it is necessary to know the various design parameters in the interior including the water temperature as the pool temperature and humidity. Following is a description of the calculation module, air handling units, including optimizing the settings of the physical changes in order to ensure the lowest energy consumption for air treatment and required maintaining internal microclimate parameters.

  18. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Maienschein, J.L.; Garcia, F.; Garza, R.G.

    Tritium-handling apparatus has been decontaminated as part of the downsizing of the LLNL Tritium Facility. Two stainless-steel glove boxes that had been used to process lithium deuteride-tritide (LiDT) slat were decontaminated using the Portable Cleanup System so that they could be flushed with room air through the facility ventilation system. In this paper the details on the decontamination operation are provided. A series of metal (palladium and vanadium) hydride storage beds have been drained of tritium and flushed with deuterium, in order to remove as much tritium as possible. The bed draining and flushing procedure is described, and a calculationalmore » method is presented which allows estimation of the tritium remaining in a bed after it has been drained and flushed. Data on specific bed draining and flushing are given.« less

  19. Optimization of heat and mass transfers in counterflow corrugated-plate liquid-gas exchangers used in a greenhouse dehumidifier

    NASA Astrophysics Data System (ADS)

    Bentounes, N.; Jaffrin, A.

    1998-09-01

    Heat and mass transfers occuring in a counterflow direct contact liquid-gas exchanger determine the performance of a new greenhouse air dehumidifier designed at INRA. This prototype uses triethylene glycol (TEG) as the desiccant fluid which extracts water vapor from the air. The regeneration of the TEG desiccant fluid is then performed by direct contact with combustion gas from a high efficiency boiler equipped with a condensor. The heat and mass transfers between the thin film of diluted TEG and the hot gas were simulated by a model which uses correlation formula from the literature specifically relevant to the present cross-corrugated plates geometry. A simple set of analytical solutions is first derived, which explains why some possible processes can clearly be far from optimal. Then, more exact numerical calculations confirm that some undesirable water recondensations on the upper part of the exchanger were limiting the performance of this prototype. More suitable conditions were defined for the process, which lead to a new design of the apparatus. In this second prototype, a gas-gas exchanger provides dryer and cooler gas to the basis of the regenerators, while a warmer TEG is fed on the top. A whole range of operating conditions was experimented and measured parameters were compared with numerical simulations of this new configuration: recondensation did not occur any more. As a consequence, this second prototype was able to concentrate the desiccant fluid at the desired rate of 20 kg H_{2O}/hour, under temperature and humidity conditions which correspond to the dehumidification of a 1000 m2 greenhouse heated at night during the winter season.

  20. Transient effects of sudden changes of heat load in a naturally ventilated room

    NASA Astrophysics Data System (ADS)

    Caulfield, C. P.; Bower, D. J.; Fitzgerald, S.; Woods, A. W.

    2006-11-01

    Using reduced numerical models and small-scale laboratory experiments, we investigate the transient effects of changing isolated heat loads discontinuously within a large, ventilated space. We consider the emptying filling box (with high and low openings) driven by a single isolated source of buoyancy. The original steady state consists of a buoyant layer, whose depth (for the simplest case of a point source plume) is determined by the geometric properties of the room alone. When the buoyancy flux of the source is increased, a new layer `fills' the room from the top with a more buoyant layer. The original layer disappears due to entrainment by the rising plume. The behaviour is qualitatively different when the source buoyancy flux is decreased. In this case, the rising plume fluid is now relatively dense, and so it inevitably collapses back to `intrude' below the original layer. In this case, the original layer disappears due to both draining through the upper opening, and penetrative entrainment by the dense plume. We compare the predictions of three numerical models using different penetrative entrainment parametrizations to a sequence of laboratory experiments. This entrainment reduces the density of the intruding layer, and so the rising plume eventually stalls, and no longer reaches the (draining) original layer. We demonstrate that it is necessary to consider the transient effects of penetrative entrainment when the reduction in source buoyancy flux is sufficiently small.

  1. Optical intensity scintillation in the simulated atmospherical environment

    NASA Astrophysics Data System (ADS)

    Hajek, Lukas; Latal, Jan; Vanderka, Ales; Vitasek, Jan; Bojko, Marian; Bednarek, Lukas; Vasinek, Vladimir

    2016-09-01

    There are several parameters of the atmospheric environment which have an effect on the optical wireless connection. Effects like fog, snow or rain are ones of the effects which appears tendentiously and which are bound by season, geographic location, etc. One of the effects that appear with various intensity for the whole time is airflow. The airflow changes the local refractive index of the air and areas with lower or higher refractive index form. The light going through these areas refracts and due to the optical intensity scintillates on the detector of the receiver. The airflow forms on the basis of two effects in the atmosphere. The first is wind cut and flowing over barriers. The other is thermal flow when warm air rises to the higher layers of the atmosphere. The heart of this article is creation such an environment that will form airflow and the refractive index will scintillate. For the experiment, we used special laboratory box with high-speed ventilators and heating units to simulate atmospheric turbulence. We monitor the impact of ventilator arrangement and air temperature on the scintillation of the gas laser with wavelength 633 nm/15 mW. In the experiment, there is watched the difference in behavior between real measurement and flow simulation with the same peripheral conditions of the airflow in the area of 500 x 500 cm.

  2. Emissions of ammonia, carbon dioxide and particulate matter from cage-free layer houses in California

    NASA Astrophysics Data System (ADS)

    Lin, Xingjun; Zhang, Ruihong; Jiang, Shumei; El-Mashad, Hamed; Xin, Hongwei

    2017-03-01

    Cage-free housing systems have attracted considerable attention in the United States recently as they provide more space and other resources (such as litter area, perches, and nest boxes) for hens and are considered to be more favorable from the standpoint of hen welfare. This study was carried out to quantify emissions of aerial ammonia (NH3), carbon dioxide (CO2) and particulate matter (PM10 and PM2.5) from cage-free layer houses in California and compare the values with those for other types of layer houses. Two commercial cage-free houses with 38,000 hens each were monitored from March 1, 2012 to April 1, 2013. Results show that NH3 and CO2 concentrations in the houses were affected by ventilation rate, which was largely influenced by ambient air temperature. The PM10 and PM2.5 concentrations in the houses depended on the activity of birds, ventilation rate and relative humidity of the ambient air. The average emission rates of NH3, CO2, PM10 and PM2.5 were 0.29, 89.9, 0.163 and 0.020 g d-1 hen-1, respectively. The NH3 emission rate determined in this study was higher than those of aviary houses. The PM10 and PM2.5 emission rates were higher than those reported for high-rise layer houses.

  3. The role of Southern Ocean mixing and upwelling in glacial-interglacial atmospheric CO2 change

    NASA Astrophysics Data System (ADS)

    Watson, Andrew J.; Naveira Garabato, Alberto C.

    2006-02-01

    Decreased ventilation of the Southern Ocean in glacial time is implicated in most explanations of lower glacial atmospheric CO2. Today, the deep (>2000 m) ocean south of the Polar Front is rapidly ventilated from below, with the interaction of deep currents with topography driving high mixing rates well up into the water column. We show from a buoyancy budget that mixing rates are high in all the deep waters of the Southern Ocean. Between the surface and ~2000 m depth, water is upwelled by a residual meridional overturning that is directly linked to buoyancy fluxes through the ocean surface. Combined with the rapid deep mixing, this upwelling serves to return deep water to the surface on a short time scale. We propose two new mechanisms by which, in glacial time, the deep Southern Ocean may have been more isolated from the surface. Firstly, the deep ocean appears to have been more stratified because of denser bottom water resulting from intense sea ice formation near Antarctica. The greater stratification would have slowed the deep mixing. Secondly, subzero atmospheric temperatures may have meant that the present-day buoyancy flux from the atmosphere to the ocean surface was reduced or reversed. This in turn would have reduced or eliminated the upwelling (contrary to a common assumption, upwelling is not solely a function of the wind stress but is coupled to the air-sea buoyancy flux too). The observed very close link between Antarctic temperatures and atmospheric CO2 could then be explained as a natural consequence of the connection between the air-sea buoyancy flux and upwelling in the Southern Ocean, if slower ventilation of the Southern Ocean led to lower atmospheric CO2. Here we use a box model, similar to those of previous authors, to show that weaker mixing and reduced upwelling in the Southern Ocean can explain the low glacial atmospheric CO2 in such a formulation.

  4. Isocapnic hyperventilation shortens washout time for sevoflurane - an experimental in vivo study.

    PubMed

    Hallén, K; Stenqvist, O; Ricksten, S-E; Lindgren, S

    2016-10-01

    Isocapnic hyperventilation (IHV) is a method that fastens weaning from inhalation anaesthesia by increasing airway concentration of carbon dioxide (CO2 ) during hyperventilation (HV). In an animal model, we evaluated a technique of adding CO2 directly to the breathing circuit of a standard anaesthesia apparatus. Eight anaesthetised pigs weighing 28 ± 2 kg were intubated and mechanically ventilated. From a baseline ventilation of 5 l/min, HV was achieved by doubling minute volume and fresh gas flow. Respiratory rate was increased from 15 to 22/min. The CO2 absorber was disconnected and CO2 was delivered (DCO2 ) to the inspiratory limb of a standard breathing circuit via a mixing box. Time required to decrease end-tidal sevoflurane concentration from 2.7% to 0.2% was defined as washout time. Respiration and haemodynamics were monitored by blood gas analysis, spirometry, electric impedance tomography and pulse contour analysis. A DCO2 of 261 ± 19 ml/min was necessary to achieve isocapnia during HV. The corresponding FICO2 -level remained stable at 3.1 ± 0.3%. During IHV, washout of sevoflurane was three times faster, 433 ± 135 s vs. 1387 ± 204 s (P < 0.001). Arterial CO2 tension and end-tidal CO2 , was 5.2 ± 0.4 kPa and 5.6 ± 0.4%, respectively, before IHV and 5.1 ± 0.3 kPa and 5.7 ± 0.3%, respectively, during IHV. In this experimental in vivo model of isocapnic hyperventilation, the washout time of sevoflurane anaesthesia was one-third compared to normal ventilation. The method for isocapnic hyperventilation described can potentially be transferred to a clinical setting with the intention to decrease emergence time from inhalation anaesthesia. © 2016 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  5. Air Conditioner/Dehumidifier

    NASA Technical Reports Server (NTRS)

    1986-01-01

    An ordinary air conditioner in a very humid environment must overcool the room air, then reheat it. Mr. Dinh, a former STAC associate, devised a heat pipe based humidifier under a NASA Contract. The system used heat pipes to precool the air; the air conditioner's cooling coil removes heat and humidity, then the heat pipes restore the overcooled air to a comfortable temperature. The heat pipes use no energy, and typical savings are from 15-20%. The Dinh Company also manufactures a "Z" coil, a retrofit cooling coil which may be installed on an existing heater/air conditioner. It will also provide free hot water. The company has also developed a photovoltaic air conditioner and solar powered water pump.

  6. Breast Cancer Research at NASA

    NASA Technical Reports Server (NTRS)

    1998-01-01

    NASA's Marshall Space Flight Center (MSFC) is sponsoring research with Bioreactors, rotating wall vessels designed to grow tissue samples in space, to understand how breast cancer works. This ground-based work studies the growth and assembly of human mammary epithelial cells (HMEC) from breast cancer susceptible tissue. Radiation can make the cells cancerous, thus allowing better comparisons of healthy vs. tunourous tissues. Here, two High-Aspect Ratio Vessels turn at about 12 rmp to keep breast tissue constructs suspended inside the culture media. Syringes allow scientists to pull for analysis during growth sequences. The tube in the center is a water bubbler that dehumidifies the air to prevent evaporation of the media and thus the appearance of destructive bubbles in the bioreactor.

  7. Analysis of a membrane-based condesate recovery heat exchanger (CRX)

    NASA Technical Reports Server (NTRS)

    Newbold, D.D.

    1993-01-01

    The development of a temperature and humidity control system that can remove heat and recover water vapor is key to the development of an Environmental Control and Life Support System (ECLSS). Large quantities of water vapor must be removed from air, and this operation has proven difficult in the absense of gravity. This paper presents the modeling results from a program to develop a novel membrane-based heat exchanger known as the condensate recovery heat exchanger (CRX). This device cools and dehumidifies humid air and simultaneously recovers water-vapor condensate. In this paper, the CRX is described and the results of an analysis of the heat- and mass-transfer characteristics of the device are given.

  8. Gas chromatographic determination of 1,4-dioxane at low parts-per-million levels in glycols.

    PubMed

    Pundlik, M D; Sitharaman, B; Kaur, I

    2001-02-01

    1,4-Dioxane is a flammable liquid and tends to form explosive peroxides. Its formation in glycols (low parts-per-million levels), which are used as dehumidifying agents in refineries, may take place by condensation. 1,4-Dioxane thus formed gets distilled over with benzene in the refinery process. Therefore, it is necessary to identify and determine the levels of 1,4-dioxane in glycols as well as benzene. Gas chromatography (GC) is probably the best technique for this purpose. GC analysis may be carried out using a flame ionization detector. Results show that 1,4-dioxane can be comfortably determined down to 2 ppm in glycols and benzene.

  9. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kerrigan, P.

    This report describes a research study that was conducted by the Building Science Corporation (BSC) Building America Research Team. BSC seeks to research and report on the field monitoring of the performance of in-situ supplemental dehumidification systems in low energy, high performance homes in a hot-humid climate. The purpose of this research project was to observe and compare the humidity control performance. Specifically, the study sought to compare the interior conditions and mechanical systems operation between two distinct groups of houses; homes with a supplemental dehumidifier installed in addition to HVAC system, and homes without any supplemental dehumidification. The subjectsmore » of the study were 10 single-family, new construction homes in New Orleans, LA.« less

  10. Microgravity

    NASA Image and Video Library

    1998-10-10

    NASA's Marshall Space Flight Center (MSFC) is sponsoring research with Bioreactors, rotating wall vessels designed to grow tissue samples in space, to understand how breast cancer works. This ground-based work studies the growth and assembly of human mammary epithelial cells (HMEC) from breast cancer susceptible tissue. Radiation can make the cells cancerous, thus allowing better comparisons of healthy vs. tunourous tissues. Here, two High-Aspect Ratio Vessels turn at about 12 rmp to keep breast tissue constructs suspended inside the culture media. Syringes allow scientists to pull for analysis during growth sequences. The tube in the center is a water bubbler that dehumidifies the air to prevent evaporation of the media and thus the appearance of destructive bubbles in the bioreactor.

  11. Evaluation of an I-box wind tunnel model for assessment of behavioral responses of blow flies.

    PubMed

    Moophayak, Kittikhun; Sukontason, Kabkaew L; Kurahashi, Hiromu; Vogtsberger, Roy C; Sukontason, Kom

    2013-11-01

    The behavioral response of flies to olfactory cues remains the focus of many investigations, and wind tunnels have sometimes been employed for assessment of this variable in the laboratory. In this study, our aim was to design, construct, and operate a new model of I-box wind tunnel with improved efficacy, highlighting the use of a new wind tunnel model to investigate the behavioral response of the medically important blow fly, Chrysomya megacephala (Fabricius). The I-box dual-choice wind tunnel designed for this study consists of seven conjoined compartments that resulted in a linear apparatus with clear glass tunnel of 30 × 30 × 190 cm ended both sides with wooden "fan compartments" which are equipped with adjustable fans as wind source. The clear glass tunnel consisted of two "stimulus compartments" with either presence or absence (control) of bait; two "trap compartments" where flies were attracted and allowed to reside; and one central "release compartment" where flies were introduced. Wind tunnel experiments were carried out in a temperature-controlled room, with a room light as a light source and a room-ventilated fan as odor-remover from tunnel out. Evaluation of testing parameters revealed that the highest attractive index was achieved with the use of 300 g of 1-day tainted pork scrap (pork meat mixed with offal) as bait in wind tunnel settings wind speed of 0.58 m/s, during 1.00-5.00 PM with light intensity of 341.33 lux from vertical light and 135.93 lux from horizontal light for testing a group of 60 flies. In addition, no significant response of well-fed and 24 h staved flies to this bait under these conditions was found. Results of this study supported this new wind tunnel model as a suitable apparatus for investigation of behavioral response of blow flies to bait chemical cues in the laboratory.

  12. Hygroscopic properties of oxalic acid and atmospherically relevant oxalates

    NASA Astrophysics Data System (ADS)

    Ma, Qingxin; He, Hong; Liu, Chang

    2013-04-01

    Oxalic acid and oxalates represent an important fraction of atmospheric organic aerosols, however, little knowledge about the hygroscopic behavior of these particles is known. In this study, the hygroscopic behavior of oxalic acid and atmospherically relevant oxalates (H2C2O4, (NH4)2C2O4, CaC2O4, and FeC2O4) were studied by Raman spectrometry and vapor sorption analyzer. Under ambient relative humidity (RH) of 10-90%, oxalic acid and these oxalates hardly deliquesce and exhibit low hygroscopicity, however, transformation between anhydrous and hydrated particles was observed during the humidifying and dehumidifying processes. During the water adsorption process, conversion of anhydrous H2C2O4, (NH4)2C2O4, CaC2O4, and FeC2O4 to their hydrated particles (i.e., H2C2O4·2H2O, (NH4)2C2O4·H2O, CaC2O4·H2O, and FeC2O4·2H2O) occurred at about 20% RH, 55% RH, 10% RH, and 75% RH, respectively. Uptake of water on hydrated Ca-oxalate and Fe-oxalate particles can be described by a multilayer adsorption isotherm. During the dehumidifying process, dehydration of H2C2O4·2H2O and (NH4)2C2O4·H2O occurred at 5% RH while CaC2O4·H2O and FeC2O4·2H2O did not undergo dehydration. These results implied that hydrated particles represent the most stable state of oxalic acid and oxalates in the atmosphere. In addition, the assignments of Raman shift bands in the range of 1610-1650 cm-1 were discussed according to the hygroscopic behavior measurement results.

  13. Models for nearly every occasion: Part III - One box decreasing emission models.

    PubMed

    Hewett, Paul; Ganser, Gary H

    2017-11-01

    New one box "well-mixed room" decreasing emission (DE) models are introduced that allow for local exhaust or local exhaust with filtered return, as well the recirculation of a filtered (or cleaned) portion of the general room ventilation. For each control device scenario, a steady state and transient model is presented. The transient equations predict the concentration at any time t after the application of a known mass of a volatile substance to a surface, and can be used to predict the task exposure profile, the average task exposure, as well as peak and short-term exposures. The steady state equations can be used to predict the "average concentration per application" that is reached whenever the substance is repeatedly applied. Whenever the beginning and end concentrations are expected to be zero (or near zero) the steady state equations can also be used to predict the average concentration for a single task with multiple applications during the task, or even a series of such tasks. The transient equations should be used whenever these criteria cannot be met. A structured calibration procedure is proposed that utilizes a mass balance approach. Depending upon the DE model selected, one or more calibration measurements are collected. Using rearranged versions of the steady state equations, estimates of the model variables-e.g., the mass of the substance applied during each application, local exhaust capture efficiency, and the various cleaning or filtration efficiencies-can be calculated. A new procedure is proposed for estimating the emission rate constant.

  14. Perceiving nasal patency through mucosal cooling rather than air temperature or nasal resistance.

    PubMed

    Zhao, Kai; Blacker, Kara; Luo, Yuehao; Bryant, Bruce; Jiang, Jianbo

    2011-01-01

    Adequate perception of nasal airflow (i.e., nasal patency) is an important consideration for patients with nasal sinus diseases. The perception of a lack of nasal patency becomes the primary symptom that drives these patients to seek medical treatment. However, clinical assessment of nasal patency remains a challenge because we lack objective measurements that correlate well with what patients perceive. The current study examined factors that may influence perceived patency, including air temperature, humidity, mucosal cooling, nasal resistance, and trigeminal sensitivity. Forty-four healthy subjects rated nasal patency while sampling air from three facial exposure boxes that were ventilated with untreated room air, cold air, and dry air, respectively. In all conditions, air temperature and relative humidity inside each box were recorded with sensors connected to a computer. Nasal resistance and minimum airway cross-sectional area (MCA) were measured using rhinomanometry and acoustic rhinometry, respectively. General trigeminal sensitivity was assessed through lateralization thresholds to butanol. No significant correlation was found between perceived patency and nasal resistance or MCA. In contrast, air temperature, humidity, and butanol threshold combined significantly contributed to the ratings of patency, with mucosal cooling (heat loss) being the most heavily weighted predictor. Air humidity significantly influences perceived patency, suggesting that mucosal cooling rather than air temperature alone provides the trigeminal sensation that results in perception of patency. The dynamic cooling between the airstream and the mucosal wall may be quantified experimentally or computationally and could potentially lead to a new clinical evaluation tool.

  15. Perceiving Nasal Patency through Mucosal Cooling Rather than Air Temperature or Nasal Resistance

    PubMed Central

    Zhao, Kai; Blacker, Kara; Luo, Yuehao; Bryant, Bruce; Jiang, Jianbo

    2011-01-01

    Adequate perception of nasal airflow (i.e., nasal patency) is an important consideration for patients with nasal sinus diseases. The perception of a lack of nasal patency becomes the primary symptom that drives these patients to seek medical treatment. However, clinical assessment of nasal patency remains a challenge because we lack objective measurements that correlate well with what patients perceive.The current study examined factors that may influence perceived patency, including air temperature, humidity, mucosal cooling, nasal resistance, and trigeminal sensitivity. Forty-four healthy subjects rated nasal patency while sampling air from three facial exposure boxes that were ventilated with untreated room air, cold air, and dry air, respectively. In all conditions, air temperature and relative humidity inside each box were recorded with sensors connected to a computer. Nasal resistance and minimum airway cross-sectional area (MCA) were measured using rhinomanometry and acoustic rhinometry, respectively. General trigeminal sensitivity was assessed through lateralization thresholds to butanol. No significant correlation was found between perceived patency and nasal resistance or MCA. In contrast, air temperature, humidity, and butanol threshold combined significantly contributed to the ratings of patency, with mucosal cooling (heat loss) being the most heavily weighted predictor. Air humidity significantly influences perceived patency, suggesting that mucosal cooling rather than air temperature alone provides the trigeminal sensation that results in perception of patency. The dynamic cooling between the airstream and the mucosal wall may be quantified experimentally or computationally and could potentially lead to a new clinical evaluation tool. PMID:22022361

  16. An innovative permanent total enclosure for blast cleaning and painting ships in drydock

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Garland, C.; Lukey, M.

    1997-12-31

    This paper describes a new innovative Permanent Total Enclosure, or CAPE system, which encloses and captures emissions from blast cleaning and painting ship hulls in drydock. A description of the modular enclosure towers with unique seals is shown with several figures. The support barge with its environmental control equipment which includes a dust collector, VOC thermal oxidizer, dehumidifier, boiler, heating coils, air flow fans and, system controls is also described. Data measurements from the first two applications rate this system at 100 percent capture efficiency, 99 percent VOC destruction efficiency and 99.9 percent dust collection efficiency. Ships can be blastmore » cleaned and painted using noncompliant paints and meet all state and federal standards for air emissions.« less

  17. Prevalence and test characteristics of national health safety network ventilator-associated events.

    PubMed

    Lilly, Craig M; Landry, Karen E; Sood, Rahul N; Dunnington, Cheryl H; Ellison, Richard T; Bagley, Peter H; Baker, Stephen P; Cody, Shawn; Irwin, Richard S

    2014-09-01

    The primary aim of the study was to measure the test characteristics of the National Health Safety Network ventilator-associated event/ventilator-associated condition constructs for detecting ventilator-associated pneumonia. Its secondary aims were to report the clinical features of patients with National Health Safety Network ventilator-associated event/ventilator-associated condition, measure costs of surveillance, and its susceptibility to manipulation. Prospective cohort study. Two inpatient campuses of an academic medical center. Eight thousand four hundred eight mechanically ventilated adults discharged from an ICU. None. The National Health Safety Network ventilator-associated event/ventilator-associated condition constructs detected less than a third of ventilator-associated pneumonia cases with a sensitivity of 0.325 and a positive predictive value of 0.07. Most National Health Safety Network ventilator-associated event/ventilator-associated condition cases (93%) did not have ventilator-associated pneumonia or other hospital-acquired complications; 71% met the definition for acute respiratory distress syndrome. Similarly, most patients with National Health Safety Network probable ventilator-associated pneumonia did not have ventilator-associated pneumonia because radiographic criteria were not met. National Health Safety Network ventilator-associated event/ventilator-associated condition rates were reduced 93% by an unsophisticated manipulation of ventilator management protocols. The National Health Safety Network ventilator-associated event/ventilator-associated condition constructs failed to detect many patients who had ventilator-associated pneumonia, detected many cases that did not have a hospital complication, and were susceptible to manipulation. National Health Safety Network ventilator-associated event/ventilator-associated condition surveillance did not perform as well as ventilator-associated pneumonia surveillance and had several undesirable characteristics.

  18. Airborne particle-bound brominated flame retardants: Levels, size distribution and indoor-outdoor exchange.

    PubMed

    Zhu, Yue-Shan; Yang, Wan-Dong; Li, Xiu-Wen; Ni, Hong-Gang; Zeng, Hui

    2018-02-01

    The quality of indoor environments has a significant impact on public health. Usually, an indoor environment is treated as a static box, in which physicochemical reactions of indoor air contaminants are negligible. This results in conservative estimates for primary indoor air pollutant concentrations, while also ignoring secondary pollutants. Thus, understanding the relationship between indoor and outdoor particles and particle-bound pollutants is of great significance. For this reason, we collected simultaneous indoor and outdoor measurements of the size distribution of airborne brominated flame retardant (BFR) congeners. The time-dependent concentrations of indoor particles and particle-bound BFRs were then estimated with the mass balance model, accounting for the outdoor concentration, indoor source strength, infiltration, penetration, deposition and indoor resuspension. Based on qualitative observation, the size distributions of ΣPBDE and ΣHBCD were characterized by bimodal peaks. According to our results, particle-bound BDE209 and γ-HBCD underwent degradation. Regardless of the surface adsorption capability of particles and the physicochemical properties of the target compounds, the concentration of BFRs in particles of different size fractions seemed to be governed by the particle distribution. Based on our estimations, for airborne particles and particle-bound BFRs, a window-open ventilated room only takes a quarter of the time to reach an equilibrium between the concentration of pollutants inside and outside compared to a closed room. Unfortunately, indoor pollutants and outdoor pollutants always exist simultaneously, which poses a window-open-or-closed dilemma to achieve proper ventilation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Respiratory parameters in elite athletes--does sport have an influence?

    PubMed

    Mazic, S; Lazovic, B; Djelic, M; Suzic-Lazic, J; Djordjevic-Saranovic, S; Durmic, T; Soldatovic, I; Zikic, D; Gluvic, Z; Zugic, V

    2015-01-01

    Unlike large population studies about cardiovascular components and how they adapt to intensive physical activity, there is less research into the causes of enlargement of the respiratory system in athletes (e.g. vital capacity, maximum flow rates and pulmonary diffusion capacity). The purpose of this research was to study and compare pulmonary function in different types of sports and compare them with controls in order to find out which sports improve lung function the most. Pulmonary functional capacities, vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and maximum voluntary ventilation (MVV) of 493 top athletes belonging to 15 different sports disciplines and of 16 sedentary individuals were studied. Pulmonary function test was performed according to ATS/ERS guidelines. Basketball, water polo players and rowers had statistically higher vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in one second (FEV1) than the healthy sedentary control individuals. Football and volleyball players had lower VC while FVC was higher in the football group compared to controls. Peak expiratory flow was lower in boxing, kayak, rugby, handball, taekwondo and tennis. The maximum voluntary ventilation (MVV) was significantly higher in water polo players and rowers. Boxers had statistically lower MVV than the controls. Players of other sports did not differ from the control group. The study suggests that specific type of training used in basketball, water polo or rowing could have potential for improving pulmonary function and rehabilitation. Copyright © 2014 Sociedade Portuguesa de Pneumologia. Published by Elsevier España, S.L.U. All rights reserved.

  20. The effect of two different intra-operative end-tidal carbon dioxide tensions on apnoeic duration in the recovery period in horses.

    PubMed

    Thompson, Kate R; Bardell, David

    2016-03-01

    To compare the effect of two different intraoperative end-tidal carbon dioxide tensions on apnoeic duration in the recovery period in horses. Prospective randomized clinical study. Eighteen healthy client-owned adult horses (ASA I-II) admitted for elective surgery. Horses were of a median body mass of 595 (238-706) kg and a mean age of 9 ± 5 years. A standardized anaesthetic protocol was used. Horses were positioned in dorsal recumbency and randomly allocated to one of two groups. Controlled mechanical ventilation (CMV) was adjusted to maintain the end-tidal carbon dioxide tension (Pe'CO2 ) at 40 ± 5 mmHg (5.3 ± 0.7 kPa) (group 40) or 60 ± 5 mmHg (8.0 ± 0.7 kPa) (group 60). Arterial blood gas analysis was performed at the start of the anaesthetic period (T0), at one point during the anaesthetic (T1), immediately prior to disconnection from the breathing system (T2) and at the first spontaneous breath in the recovery box (T3). The time from disconnection from the breathing system to return to spontaneous ventilation (RSV) was recorded. Data were analysed using a two sample t-test or the Mann-Whitney U-test and significance assigned when p < 0.05. Horses in group 60 resumed spontaneous breathing significantly earlier than those in group 40, [52 (14-151) and 210 (103-542) seconds, respectively] (p < 0.001). Arterial oxygen tension (PaO2 ), pH, base excess (BE) and plasma bicarbonate (HCO3-) were not different between the groups at RSV, however, PaO2 was significantly lower in group 60 during (T1) and at the end of anaesthesia (T2). Aiming to maintain intra-operative Pe'CO2 at 60 ± 5 mmHg (8.0 ± 0.7 kPa) in mechanically ventilated horses resulted in more rapid RSV compared with when Pe'CO2 was maintained at 40 ± 5 mmHg (5.3 ± 0.7 kPa). © 2015 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.

  1. Anaesthesia ventilators.

    PubMed

    Jain, Rajnish K; Swaminathan, Srinivasan

    2013-09-01

    Anaesthesia ventilators are an integral part of all modern anaesthesia workstations. Automatic ventilators in the operating rooms, which were very simple with few modes of ventilation when introduced, have become very sophisticated with many advanced ventilation modes. Several systems of classification of anaesthesia ventilators exist based upon various parameters. Modern anaesthesia ventilators have either a double circuit, bellow design or a single circuit piston configuration. In the bellows ventilators, ascending bellows design is safer than descending bellows. Piston ventilators have the advantage of delivering accurate tidal volume. They work with electricity as their driving force and do not require a driving gas. To enable improved patient safety, several modifications were done in circle system with the different types of anaesthesia ventilators. Fresh gas decoupling is a modification done in piston ventilators and in descending bellows ventilator to reduce th incidence of ventilator induced volutrauma. In addition to the conventional volume control mode, modern anaesthesia ventilators also provide newer modes of ventilation such as synchronised intermittent mandatory ventilation, pressure-control ventilation and pressure-support ventilation (PSV). PSV mode is particularly useful for patients maintained on spontaneous respiration with laryngeal mask airway. Along with the innumerable benefits provided by these machines, there are various inherent hazards associated with the use of the ventilators in the operating room. To use these workstations safely, it is important for every Anaesthesiologist to have a basic understanding of the mechanics of these ventilators and breathing circuits.

  2. Evaluation of ventilators for mouthpiece ventilation in neuromuscular disease.

    PubMed

    Khirani, Sonia; Ramirez, Adriana; Delord, Vincent; Leroux, Karl; Lofaso, Frédéric; Hautot, Solène; Toussaint, Michel; Orlikowski, David; Louis, Bruno; Fauroux, Brigitte

    2014-09-01

    Daytime mouthpiece ventilation is a useful adjunct to nocturnal noninvasive ventilation (NIV) in patients with neuromuscular disease. The aims of the study were to analyze the practice of mouthpiece ventilation and to evaluate the performance of ventilators for mouthpiece ventilation. Practice of mouthpiece ventilation was assessed by a questionnaire, and the performance of 6 home ventilators with mouthpiece ventilation was assessed in a bench test using 24 different conditions per ventilator: 3 mouthpieces, a child and an adult patient profile, and 4 ventilatory modes. Questionnaires were obtained from 30 subjects (mean age 33 ± 11 y) using NIV for 12 ± 7 y. Fifteen subjects used NIV for > 20 h/day, and 11 were totally ventilator-dependent. The subject-reported benefits of mouthpiece ventilation were a reduction in dyspnea (73%) and fatigue (93%) and an improvement in speech (43%) and eating (27%). The bench study showed that none of the ventilators, even those with mouthpiece ventilation software, were able to deliver mouthpiece ventilation without alarms and/or autotriggering in each condition. Alarms and/or ineffective triggering or autotriggering were observed in 135 of the 198 conditions. The occurrence of alarms was more common with a large mouthpiece without a filter compared to a small mouthpiece with a filter (P < .001), but it was not related to the patient profile, the ventilatory mode, or the type of ventilator. Subjects are satisfied with mouthpiece ventilation. Alarms are common with home ventilators, although less common in those with mouthpiece ventilation software. Improvements in home ventilators are needed to facilitate the expansion of mouthpiece ventilation. Copyright © 2014 by Daedalus Enterprises.

  3. Nonlinear optimal control policies for buoyancy-driven flows in the built environment

    NASA Astrophysics Data System (ADS)

    Nabi, Saleh; Grover, Piyush; Caulfield, Colm

    2017-11-01

    We consider optimal control of turbulent buoyancy-driven flows in the built environment, focusing on a model test case of displacement ventilation with a time-varying heat source. The flow is modeled using the unsteady Reynolds-averaged equations (URANS). To understand the stratification dynamics better, we derive a low-order partial-mixing ODE model extending the buoyancy-driven emptying filling box problem to the case of where both the heat source and the (controlled) inlet flow are time-varying. In the limit of a single step-change in the heat source strength, our model is consistent with that of Bower et al.. Our model considers the dynamics of both `filling' and `intruding' added layers due to a time-varying source and inlet flow. A nonlinear direct-adjoint-looping optimal control formulation yields time-varying values of temperature and velocity of the inlet flow that lead to `optimal' time-averaged temperature relative to appropriate objective functionals in a region of interest.

  4. Potential risk for bacterial contamination in conventional reused ventilator systems and disposable closed ventilator-suction systems.

    PubMed

    Li, Ya-Chi; Lin, Hui-Ling; Liao, Fang-Chun; Wang, Sing-Siang; Chang, Hsiu-Chu; Hsu, Hung-Fu; Chen, Sue-Hsien; Wan, Gwo-Hwa

    2018-01-01

    Few studies have investigated the difference in bacterial contamination between conventional reused ventilator systems and disposable closed ventilator-suction systems. The aim of this study was to investigate the bacterial contamination rates of the reused and disposable ventilator systems, and the association between system disconnection and bacterial contamination of ventilator systems. The enrolled intubated and mechanically ventilated patients used a conventional reused ventilator system and a disposable closed ventilator-suction system, respectively, for a week; specimens were then collected from the ventilator circuit systems to evaluate human and environmental bacterial contamination. The sputum specimens from patients were also analyzed in this study. The detection rate of bacteria in the conventional reused ventilator system was substantially higher than that in the disposable ventilator system. The inspiratory and expiratory limbs of the disposable closed ventilator-suction system had higher bacterial concentrations than the conventional reused ventilator system. The bacterial concentration in the heated humidifier of the reused ventilator system was significantly higher than that in the disposable ventilator system. Positive associations existed among the bacterial concentrations at different locations in the reused and disposable ventilator systems, respectively. The predominant bacteria identified in the reused and disposable ventilator systems included Acinetobacter spp., Bacillus cereus, Elizabethkingia spp., Pseudomonas spp., and Stenotrophomonas (Xan) maltophilia. Both the reused and disposable ventilator systems had high bacterial contamination rates after one week of use. Disconnection of the ventilator systems should be avoided during system operation to decrease the risks of environmental pollution and human exposure, especially for the disposable ventilator system. ClinicalTrials.gov PRS / NCT03359148.

  5. A new system for understanding modes of mechanical ventilation.

    PubMed

    Chatburn, R L; Primiano, F P

    2001-06-01

    Numerous ventilation modes and ventilation options have become available as new mechanical ventilators have reached the market. Ventilator manufacturers have no standardized terminology for ventilator modes and ventilation options, and ventilator operator's manuals do not help the clinician compare the modes of ventilators from different manufacturers. This article proposes a standardized system for classifying ventilation modes, based on general engineering principles and a small set of explicit definitions. Though there may be resistance by ventilator manufacturers to a standardized system of ventilation terminology, clinicians and health care equipment purchasers should adopt such a system in the interest of clear communication--the lack of which prevents clinicians from fully understanding the therapies they administer and could compromise the quality of patient care.

  6. Potential risk for bacterial contamination in conventional reused ventilator systems and disposable closed ventilator-suction systems

    PubMed Central

    Li, Ya-Chi; Lin, Hui-Ling; Liao, Fang-Chun; Wang, Sing-Siang; Chang, Hsiu-Chu; Hsu, Hung-Fu; Chen, Sue-Hsien

    2018-01-01

    Background Few studies have investigated the difference in bacterial contamination between conventional reused ventilator systems and disposable closed ventilator-suction systems. The aim of this study was to investigate the bacterial contamination rates of the reused and disposable ventilator systems, and the association between system disconnection and bacterial contamination of ventilator systems. Methods The enrolled intubated and mechanically ventilated patients used a conventional reused ventilator system and a disposable closed ventilator-suction system, respectively, for a week; specimens were then collected from the ventilator circuit systems to evaluate human and environmental bacterial contamination. The sputum specimens from patients were also analyzed in this study. Results The detection rate of bacteria in the conventional reused ventilator system was substantially higher than that in the disposable ventilator system. The inspiratory and expiratory limbs of the disposable closed ventilator-suction system had higher bacterial concentrations than the conventional reused ventilator system. The bacterial concentration in the heated humidifier of the reused ventilator system was significantly higher than that in the disposable ventilator system. Positive associations existed among the bacterial concentrations at different locations in the reused and disposable ventilator systems, respectively. The predominant bacteria identified in the reused and disposable ventilator systems included Acinetobacter spp., Bacillus cereus, Elizabethkingia spp., Pseudomonas spp., and Stenotrophomonas (Xan) maltophilia. Conclusions Both the reused and disposable ventilator systems had high bacterial contamination rates after one week of use. Disconnection of the ventilator systems should be avoided during system operation to decrease the risks of environmental pollution and human exposure, especially for the disposable ventilator system. Trial registration ClinicalTrials.gov PRS / NCT03359148 PMID:29547638

  7. Initial mechanical ventilator settings and lung protective ventilation in the ED.

    PubMed

    Wilcox, Susan R; Richards, Jeremy B; Fisher, Daniel F; Sankoff, Jeffrey; Seigel, Todd A

    2016-08-01

    Mechanical ventilation with low tidal volumes has been shown to improve outcomes for patients both with and without acute respiratory distress syndrome. This study aims to characterize mechanically ventilated patients in the emergency department (ED), describe the initial ED ventilator settings, and assess for associations between lung protective ventilation strategies in the ED and outcomes. This was a multicenter, prospective, observational study of mechanical ventilation at 3 academic EDs. We defined lung protective ventilation as a tidal volume of less than or equal to 8 mL/kg of predicted body weight and compared outcomes for patients ventilated with lung protective vs non-lung protective ventilation, including inhospital mortality, ventilator days, intensive care unit length of stay, and hospital length of stay. Data from 433 patients were analyzed. Altered mental status without respiratory pathology was the most common reason for intubation, followed by trauma and respiratory failure. Two hundred sixty-one patients (60.3%) received lung protective ventilation, but most patients were ventilated with a low positive end-expiratory pressure, high fraction of inspired oxygen strategy. Patients were ventilated in the ED for a mean of 5 hours and 7 minutes but had few ventilator adjustments. Outcomes were not significantly different between patients receiving lung protective vs non-lung protective ventilation. Nearly 40% of ED patients were ventilated with non-lung protective ventilation as well as with low positive end-expiratory pressure and high fraction of inspired oxygen. Despite a mean ED ventilation time of more than 5 hours, few patients had adjustments made to their ventilators. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Are we fully utilizing the functionalities of modern operating room ventilators?

    PubMed

    Liu, Shujie; Kacmarek, Robert M; Oto, Jun

    2017-12-01

    The modern operating room ventilators have become very sophisticated and many of their features are comparable with those of an ICU ventilator. To fully utilize the functionality of modern operating room ventilators, it is important for clinicians to understand in depth the working principle of these ventilators and their functionalities. Piston ventilators have the advantages of delivering accurate tidal volume and certain flow compensation functions. Turbine ventilators have great ability of flow compensation. Ventilation modes are mainly volume-based or pressure-based. Pressure-based ventilation modes provide better leak compensation than volume-based. The integration of advanced flow generation systems and ventilation modes of the modern operating room ventilators enables clinicians to provide both invasive and noninvasive ventilation in perioperative settings. Ventilator waveforms can be used for intraoperative neuromonitoring during cervical spine surgery. The increase in number of new features of modern operating room ventilators clearly creates the opportunity for clinicians to optimize ventilatory care. However, improving the quality of ventilator care relies on a complete understanding and correct use of these new features. VIDEO ABSTRACT: http://links.lww.com/COAN/A47.

  9. A randomised crossover comparison of mouth-to-face-shield ventilation and mouth-to-pocket-mask ventilation by surf lifeguards in a manikin.

    PubMed

    Adelborg, K; Bjørnshave, K; Mortensen, M B; Espeseth, E; Wolff, A; Løfgren, B

    2014-07-01

    Thirty surf lifeguards (mean (SD) age: 25.1 (4.8) years; 21 male, 9 female) were randomly assigned to perform 2 × 3 min of cardiopulmonary resuscitation on a manikin using mouth-to-face-shield ventilation (AMBU LifeKey) and mouth-to-pocket-mask ventilation (Laerdal Pocket Mask). Interruptions in chest compressions, effective ventilation (visible chest rise) ratio, tidal volume and inspiratory time were recorded. Interruptions in chest compressions per cycle were increased with mouth-to-face-shield ventilation (mean (SD) 8.6 (1.7) s) compared with mouth-to-pocket-mask ventilation (6.9 (1.2) s, p < 0.0001). The proportion of effective ventilations was less using mouth-to-face-shield ventilation (199/242 (82%)) compared with mouth-to-pocket-mask ventilation (239/240 (100%), p = 0.0002). Tidal volume was lower using mouth-to-face-shield ventilation (mean (SD) 0.36 (0.20) l) compared with mouth-to-pocket-mask ventilation (0.45 (0.20) l, p = 0.006). No differences in inspiratory times were observed between mouth-to-face-shield ventilation and mouth-to-pocket-mask ventilation. In conclusion, mouth-to-face-shield ventilation increases interruptions in chest compressions, reduces the proportion of effective ventilations and decreases delivered tidal volumes compared with mouth-to-pocket-mask ventilation. © 2014 The Association of Anaesthetists of Great Britain and Ireland.

  10. [Neurally adjusted ventilatory assist (NAVA). A new mode of assisted mechanical ventilation].

    PubMed

    Moerer, O; Barwing, J; Quintel, M

    2008-10-01

    The aim of mechanical ventilation is to assure gas exchange while efficiently unloading the respiratory muscles and mechanical ventilation is an integral part of the care of patients with acute respiratory failure. Modern lung protective strategies of mechanical ventilation include low-tidal-volume ventilation and the continuation of spontaneous breathing which has been shown to be beneficial in reducing atelectasis and improving oxygenation. Poor patient-ventilator interaction is a major issue during conventional assisted ventilation. Neurally adjusted ventilator assist (NAVA) is a new mode of mechanical ventilation that uses the electrical activity of the diaphragm (EAdi) to control the ventilator. First experimental studies showed an improved patient-ventilator synchrony and an efficient unloading of the respiratory muscles. Future clinical studies will have to show that NAVA is of clinical advantage when compared to conventional modes of assisted mechanical ventilation. This review characterizes NAVA according to current publications on this topic.

  11. Antibiotic therapy in ventilator-associated tracheobronchitis: a literature review.

    PubMed

    Alves, Abel Eduardo; Pereira, José Manuel

    2018-03-01

    The concept of ventilator-associated tracheobronchitis is controversial; its definition is not unanimously accepted and often overlaps with ventilator-associated pneumonia. Ventilator-associated tracheobronchitis has an incidence similar to that of ventilator-associated pneumonia, with a high prevalence of isolated multiresistant agents, resulting in an increase in the time of mechanical ventilation and hospitalization but without an impact on mortality. The performance of quantitative cultures may allow better diagnostic definition of tracheobronchitis associated with mechanical ventilation, possibly avoiding the overdiagnosis of this condition. One of the major difficulties in differentiating between ventilator-associated tracheobronchitis and ventilator-associated pneumonia is the exclusion of a pulmonary infiltrate by chest radiography; thoracic computed tomography, thoracic ultrasonography, or invasive specimen collection may also be required. The institution of systemic antibiotic therapy does not improve the clinical impact of ventilator-associated tracheobronchitis, particularly in reducing time of mechanical ventilation, hospitalization or mortality, despite the possible reduced progression to ventilator-associated pneumonia. However, there are doubts regarding the methodology used. Thus, considering the high prevalence of tracheobronchitis associated with mechanical ventilation, routine treatment of this condition would result in high antibiotic usage without clear benefits. However, we suggest the institution of antibiotic therapy in patients with tracheobronchitis associated with mechanical ventilation and septic shock and/or worsening of oxygenation, and other auxiliary diagnostic tests should be simultaneously performed to exclude ventilator-associated pneumonia. This review provides a better understanding of the differentiation between tracheobronchitis associated with mechanical ventilation and pneumonia associated with mechanical ventilation, which can significantly decrease the use of antibiotics in critically ventilated patients.

  12. Tracheostomy and invasive mechanical ventilation in amyotrophic lateral sclerosis: decision-making factors and survival analysis.

    PubMed

    Kimura, Fumiharu

    2016-04-28

    Invasive and/or non-invasive mechanical ventilation are most important options of respiratory management in amyotrophic lateral sclerosis. We evaluated the frequency, clinical characteristics, decision-making factors about ventilation and survival analysis of 190 people with amyotrophic lateral sclerosis patients from 1990 until 2013. Thirty-one percentage of patients underwent tracheostomy invasive ventilation with the rate increasing more than the past 20 years. The ratio of tracheostomy invasive ventilation in patients >65 years old was significantly increased after 2000 (25%) as compared to before (10%). After 2010, the standard use of non-invasive ventilation showed a tendency to reduce the frequency of tracheostomy invasive ventilation. Mechanical ventilation prolonged median survival (75 months in tracheostomy invasive ventilation, 43 months in non-invasive ventilation vs natural course, 32 months). The life-extending effects by tracheostomy invasive ventilation were longer in younger patients ≤65 years old at the time of ventilation support than in older patients. Presence of partners and care at home were associated with better survival. Following factors related to the decision to perform tracheostomy invasive ventilation: patients ≤65 years old: greater use of non-invasive ventilation: presence of a spouse: faster tracheostomy: higher progression rate; and preserved motor functions. No patients who underwent tracheostomy invasive ventilation died from a decision to withdraw mechanical ventilation. The present study provides factors related to decision-making process and survival after tracheostomy and help clinicians and family members to expand the knowledge about ventilation.

  13. Closed-loop mechanical ventilation for lung injury: a novel physiological-feedback mode following the principles of the open lung concept.

    PubMed

    Schwaiberger, David; Pickerodt, Philipp A; Pomprapa, Anake; Tjarks, Onno; Kork, Felix; Boemke, Willehad; Francis, Roland C E; Leonhardt, Steffen; Lachmann, Burkhard

    2018-06-01

    Adherence to low tidal volume (V T ) ventilation and selected positive end-expiratory pressures are low during mechanical ventilation for treatment of the acute respiratory distress syndrome. Using a pig model of severe lung injury, we tested the feasibility and physiological responses to a novel fully closed-loop mechanical ventilation algorithm based on the "open lung" concept. Lung injury was induced by surfactant washout in pigs (n = 8). Animals were ventilated following the principles of the "open lung approach" (OLA) using a fully closed-loop physiological feedback algorithm for mechanical ventilation. Standard gas exchange, respiratory- and hemodynamic parameters were measured. Electrical impedance tomography was used to quantify regional ventilation distribution during mechanical ventilation. Automatized mechanical ventilation provided strict adherence to low V T -ventilation for 6 h in severely lung injured pigs. Using the "open lung" approach, tidal volume delivery required low lung distending pressures, increased recruitment and ventilation of dorsal lung regions and improved arterial blood oxygenation. Physiological feedback closed-loop mechanical ventilation according to the principles of the open lung concept is feasible and provides low tidal volume ventilation without human intervention. Of importance, the "open lung approach"-ventilation improved gas exchange and reduced lung driving pressures by opening atelectasis and shifting of ventilation to dorsal lung regions.

  14. Epidemiology of Noninvasive Ventilation in Pediatric Cardiac ICUs.

    PubMed

    Romans, Ryan A; Schwartz, Steven M; Costello, John M; Chanani, Nikhil K; Prodhan, Parthak; Gazit, Avihu Z; Smith, Andrew H; Cooper, David S; Alten, Jeffrey; Mistry, Kshitij P; Zhang, Wenying; Donohue, Janet E; Gaies, Michael

    2017-10-01

    To describe the epidemiology of noninvasive ventilation therapy for patients admitted to pediatric cardiac ICUs and to assess practice variation across hospitals. Retrospective cohort study using prospectively collected clinical registry data. Pediatric Cardiac Critical Care Consortium clinical registry. Patients admitted to cardiac ICUs at PC4 hospitals. None. We analyzed all cardiac ICU encounters that included any respiratory support from October 2013 to December 2015. Noninvasive ventilation therapy included high flow nasal cannula and positive airway pressure support. We compared patient and, when relevant, perioperative characteristics of those receiving noninvasive ventilation to all others. Subgroup analysis was performed on neonates and infants undergoing major cardiovascular surgery. To examine duration of respiratory support, we created a casemix-adjustment model and calculated adjusted mean durations of total respiratory support (mechanical ventilation + noninvasive ventilation), mechanical ventilation, and noninvasive ventilation. We compared adjusted duration of support across hospitals. The cohort included 8,940 encounters from 15 hospitals: 3,950 (44%) received noninvasive ventilation and 72% were neonates and infants. Medical encounters were more likely to include noninvasive ventilation than surgical. In surgical neonates and infants, 2,032 (55%) received postoperative noninvasive ventilation. Neonates, extracardiac anomalies, single ventricle, procedure complexity, preoperative respiratory support, mechanical ventilation duration, and postoperative disease severity were associated with noninvasive ventilation therapy (p < 0.001 for all). Across hospitals, noninvasive ventilation use ranged from 32% to 65%, and adjusted mean noninvasive ventilation duration ranged from 1 to 4 days (3-d observed mean). Duration of total adjusted respiratory support was more strongly correlated with duration of mechanical ventilation compared with noninvasive ventilation (Pearson r = 0.93 vs 0.71, respectively). Noninvasive ventilation use is common in cardiac ICUs, especially in patients admitted for medical conditions, infants, and those undergoing high complexity surgery. We observed wide variation in noninvasive ventilation use across hospitals, though the primary driver of total respiratory support time seems to be duration of mechanical ventilation.

  15. Interactive simulation system for artificial ventilation on the internet: virtual ventilator.

    PubMed

    Takeuchi, Akihiro; Abe, Tadashi; Hirose, Minoru; Kamioka, Koichi; Hamada, Atsushi; Ikeda, Noriaki

    2004-12-01

    To develop an interactive simulation system "virtual ventilator" that demonstrates the dynamics of pressure and flow in the respiratory system under the combination of spontaneous breathing, ventilation modes, and ventilator options. The simulation system was designed to be used by unexperienced health care professionals as a self-training tool. The system consists of a simulation controller and three modules: respiratory, spontaneous breath, and ventilator. The respiratory module models the respiratory system by three resistances representing the main airway, the right and left lungs, and two compliances also representing the right and left lungs. The spontaneous breath module generates inspiratory negative pressure produced by a patient. The ventilator module generates driving force of pressure or flow according to the combination of the ventilation mode and options. These forces are given to the respiratory module through the simulation controller. The simulation system was developed using HTML, VBScript (3000 lines, 100 kB) and ActiveX control (120 kB), and runs on Internet Explorer (5.5 or higher). The spontaneous breath is defined by a frequency, amplitude and inspiratory patterns in the spontaneous breath module. The user can construct a ventilation mode by setting a control variable, phase variables (trigger, limit, and cycle), and options. Available ventilation modes are: controlled mechanical ventilation (CMV), continuous positive airway pressure, synchronized intermittent mandatory ventilation (SIMV), pressure support ventilation (PSV), SIMV + PSV, pressure-controlled ventilation (PCV), pressure-regulated volume control (PRVC), proportional assisted ventilation, mandatory minute ventilation (MMV), bilevel positive airway pressure (BiPAP). The simulation system demonstrates in a graph and animation the airway pressure, flow, and volume of the respiratory system during mechanical ventilation both with and without spontaneous breathing. We developed a web application that demonstrated the respiratory mechanics and the basic theory of ventilation mode.

  16. Molds in floor dust and building-related symptoms among adolescent school children: a problem for boys only?

    PubMed

    Meyer, H W; Würtz, H; Suadicani, P; Valbjørn, O; Sigsgaard, T; Gyntelberg, F

    2005-01-01

    In this stratified cross-sectional study in eight 'wet' and seven 'dry' schools, 1024 adolescent school children reported potentially building-related symptoms (BRS) in self-administrated questionnaires. From their classrooms dust samples were collected from floors, ventilation ducts, and air; settled dust was collected in cardboard boxes over a period of 5 months. Measurements of temperature, relative humidity and CO2 were performed. BRS were strongly associated with personal factors like recent airway infections, hay fever, asthma and psycho-social work load, but also to molds in floor dust and presence of mechanical ventilation. The association between molds in floor dust and BRS has in stratified analyses shown a strong association among adolescent school boys, and no association among adolescent school girls using multivariable analyses controlling for relevant confounders. In contrast to the menstruating school girls, the symptoms among the small group of not yet menstruating girls were associated with the levels of molds in floor dust. Their symptom prevalences were very similar to those of the boys. This finding makes us suggest a new hypothesis: The higher endogenous estrogen levels of sexually matured adolescent females seems to protect them from the effects of molds in dust, despite their overall higher symptom prevalence. In this cross-sectional epidemiological study of adolescent school children we found independent significant positive associations between building-related symptoms and viable molds in floor dust in boys and non-menstruating girls. In contrast, no such associations were seen among menstruating girls. The identification of these two susceptible groups adds further support the relevance of minimizing sources of dust and mold exposure.

  17. The feasibility of laryngoscope-guided tracheal intubation in microgravity during parabolic flight: a comparison of two techniques.

    PubMed

    Groemer, Gernot E; Brimacombe, Joseph; Haas, Thorsten; de Negueruela, Cristina; Soucek, Alexander; Thomsen, Michael; Keller, Christian

    2005-11-01

    We determined the feasibility of laryngoscope-guided tracheal intubation (LG-TI) in microgravity obtained during parabolic flight and tested the hypothesis that LG-TI is similarly successful in the free-floating condition, with the patient's head gripped between the anesthesiologist's knees, as in the restrained condition, with the torso strapped to the surface. Three personnel with no experience in airway management or microgravity participated in the study. LG-TI of a sophisticated full-size manikin was attempted on seven occasions in each condition by each investigator after ground-based training. The parabolic flights, which took place in an Airbus 300 over the Atlantic Ocean, provided 23 s of microgravity. During this time, the investigator opened a box with airway equipment, performed LG-TI, and attached and held onto a self-inflating bag. The efficacy of ventilation was assessed during level flight by squeezing the bag and noting whether the manikin sensors indicated a tidal volume > or =300 mL. There were no differences in ventilation success (41% versus 33%) or time to successful insertion (both 18 s) between the free-floating and the restrained conditions. More than 90% of failures were caused by the inability to insert the tracheal tube within 23 s. There were no differences in performance among investigators. We conclude that LG-TI is feasible in microgravity obtained during parabolic flight, but the success rate is infrequent because of severe time restrictions. There were no differences in success rate between the free-floating condition, with the head gripped between the knees, and the restrained condition, with the torso strapped to the surface.

  18. Comparison of 4-Dimensional Computed Tomography Ventilation With Nuclear Medicine Ventilation-Perfusion Imaging: A Clinical Validation Study

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Vinogradskiy, Yevgeniy, E-mail: yevgeniy.vinogradskiy@ucdenver.edu; Koo, Phillip J.; Castillo, Richard

    Purpose: Four-dimensional computed tomography (4DCT) ventilation imaging provides lung function information for lung cancer patients undergoing radiation therapy. Before 4DCT-ventilation can be implemented clinically it needs to be validated against an established imaging modality. The purpose of this work was to compare 4DCT-ventilation to nuclear medicine ventilation, using clinically relevant global metrics and radiologist observations. Methods and Materials: Fifteen lung cancer patients with 16 sets of 4DCT and nuclear medicine ventilation-perfusion (VQ) images were used for the study. The VQ-ventilation images were acquired in planar mode using Tc-99m-labeled diethylenetriamine-pentaacetic acid aerosol inhalation. 4DCT data, spatial registration, and a density-change-based modelmore » were used to compute a 4DCT-based ventilation map for each patient. The percent ventilation was calculated in each lung and each lung third for both the 4DCT and VQ-ventilation scans. A nuclear medicine radiologist assessed the VQ and 4DCT scans for the presence of ventilation defects. The VQ and 4DCT-based images were compared using regional percent ventilation and radiologist clinical observations. Results: Individual patient examples demonstrate good qualitative agreement between the 4DCT and VQ-ventilation scans. The correlation coefficients were 0.68 and 0.45, using the percent ventilation in each individual lung and lung third, respectively. Using radiologist-noted presence of ventilation defects and receiver operating characteristic analysis, the sensitivity, specificity, and accuracy of the 4DCT-ventilation were 90%, 64%, and 81%, respectively. Conclusions: The current work compared 4DCT with VQ-based ventilation using clinically relevant global metrics and radiologist observations. We found good agreement between the radiologist's assessment of the 4DCT and VQ-ventilation images as well as the percent ventilation in each lung. The agreement lessened when the data were analyzed on a regional level. Our study presents an important step for the integration of 4DCT-ventilation into thoracic clinical practice.« less

  19. Impact of Room Ventilation Rates on Mouse Cage Ventilation and Microenvironment.

    PubMed

    Reeb, Carolyn K.; Jones, Robert B.; Bearg, David W.; Bedigian, Hendrick; Paigen, Beverly

    1997-01-01

    To assess the impact of room ventilation on animal cage microenvironment, intracage ventilation rate, temperature, humidity, and concentrations of carbon dioxide and ammonia were monitored in nonpressurized, bonnet-topped mouse cages. Cages on the top, middle, and bottom rows of a mouse rack were monitored at room ventilation rates of 0, 5, 10, and 20 air changes/h (ACH). Ventilation inside the animal cage increased somewhat from 12.8 to 18.9 ACH as room ventilation rate in- creased from 0 to 20 ACH, but the differences were not statistically significant, and most of the increase occurred in cages in the top row nearest to the fresh air supply. Cages containing mice had ventilation rate between 10 and 15 ACH even when room ventilation was reduced to 0 ACH; this ventilation is a result of the thermal heat load of the mice. After 6 days of soiled bedding, intracage ammonia concentration was c 3 ppm at all room ventilation rates and was not affected by increasing room ventilation. Temperature inside cages did not change with increasing ventilation. Humidity inside cages significantly decreased with increasing ventilation, from 55% relative humidity at 5 ACH to 36% relative humidity at 20 ACH. Carbon dioxide concentration decreased from 2,500 ppm to 1,900 ppm when ventilation rate increased from 5 ACH to 10 ACH, but no further significant decrease was observed at 20 ACH. In conclusion, increasing the room ventilation rate higher than 5 ACH did not result in significant improvements in the cage microenvironment.

  20. Variable mechanical ventilation

    PubMed Central

    Fontela, Paula Caitano; Prestes, Renata Bernardy; Forgiarini Jr., Luiz Alberto; Friedman, Gilberto

    2017-01-01

    Objective To review the literature on the use of variable mechanical ventilation and the main outcomes of this technique. Methods Search, selection, and analysis of all original articles on variable ventilation, without restriction on the period of publication and language, available in the electronic databases LILACS, MEDLINE®, and PubMed, by searching the terms "variable ventilation" OR "noisy ventilation" OR "biologically variable ventilation". Results A total of 36 studies were selected. Of these, 24 were original studies, including 21 experimental studies and three clinical studies. Conclusion Several experimental studies reported the beneficial effects of distinct variable ventilation strategies on lung function using different models of lung injury and healthy lungs. Variable ventilation seems to be a viable strategy for improving gas exchange and respiratory mechanics and preventing lung injury associated with mechanical ventilation. However, further clinical studies are necessary to assess the potential of variable ventilation strategies for the clinical improvement of patients undergoing mechanical ventilation. PMID:28444076

  1. Effects of positive end-expiratory pressure and recruitment maneuvers in a ventilator-induced injury mouse model

    PubMed Central

    Franzi, Lisa M.; Linderholm, Angela L.; Last, Jerold A.; Adams, Jason Y.; Harper, Richart W.

    2017-01-01

    Background Positive-pressure mechanical ventilation is an essential therapeutic intervention, yet it causes the clinical syndrome known as ventilator-induced lung injury. Various lung protective mechanical ventilation strategies have attempted to reduce or prevent ventilator-induced lung injury but few modalities have proven effective. A model that isolates the contribution of mechanical ventilation on the development of acute lung injury is needed to better understand biologic mechanisms that lead to ventilator-induced lung injury. Objectives To evaluate the effects of positive end-expiratory pressure and recruitment maneuvers in reducing lung injury in a ventilator-induced lung injury murine model in short- and longer-term ventilation. Methods 5–12 week-old female BALB/c mice (n = 85) were anesthetized, placed on mechanical ventilation for either 2 hrs or 4 hrs with either low tidal volume (8 ml/kg) or high tidal volume (15 ml/kg) with or without positive end-expiratory pressure and recruitment maneuvers. Results Alteration of the alveolar-capillary barrier was noted at 2 hrs of high tidal volume ventilation. Standardized histology scores, influx of bronchoalveolar lavage albumin, proinflammatory cytokines, and absolute neutrophils were significantly higher in the high-tidal volume ventilation group at 4 hours of ventilation. Application of positive end-expiratory pressure resulted in significantly decreased standardized histology scores and bronchoalveolar absolute neutrophil counts at low- and high-tidal volume ventilation, respectively. Recruitment maneuvers were essential to maintain pulmonary compliance at both 2 and 4 hrs of ventilation. Conclusions Signs of ventilator-induced lung injury are evident soon after high tidal volume ventilation (as early as 2 hours) and lung injury worsens with longer-term ventilation (4 hrs). Application of positive end-expiratory pressure and recruitment maneuvers are protective against worsening VILI across all time points. Dynamic compliance can be used guide the frequency of recruitment maneuvers to help ameloriate ventilator-induced lung injury. PMID:29112971

  2. 46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-1 Power ventilation systems except machinery space ventilation systems. Each power ventilation system must... 46 Shipping 4 2010-10-01 2010-10-01 false Power ventilation systems except machinery space...

  3. 46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-1 Power ventilation systems except machinery space ventilation systems. Each power ventilation system must... 46 Shipping 4 2011-10-01 2011-10-01 false Power ventilation systems except machinery space...

  4. 46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-1 Power ventilation systems except machinery space ventilation systems. Each power ventilation system must... 46 Shipping 4 2014-10-01 2014-10-01 false Power ventilation systems except machinery space...

  5. 46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-1 Power ventilation systems except machinery space ventilation systems. Each power ventilation system must... 46 Shipping 4 2012-10-01 2012-10-01 false Power ventilation systems except machinery space...

  6. 46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-1 Power ventilation systems except machinery space ventilation systems. Each power ventilation system must... 46 Shipping 4 2013-10-01 2013-10-01 false Power ventilation systems except machinery space...

  7. A regulator for pressure-controlled total-liquid ventilation.

    PubMed

    Robert, Raymond; Micheau, Philippe; Avoine, Olivier; Beaudry, Benoit; Beaulieu, Alexandre; Walti, Hervé

    2010-09-01

    Total-liquid ventilation (TLV) is an innovative experimental method of mechanical-assisted ventilation in which lungs are totally filled and then ventilated with a tidal volume of perfluorochemical liquid by using a dedicated liquid ventilator. Such a novel medical device must resemble other conventional ventilators: it must be able to conduct controlled-pressure ventilation. The objective was to design a robust controller to perform pressure-regulated expiratory flow and to implement it on our latest liquid-ventilator prototype (Inolivent-4). Numerical simulations, in vitro experiments, and in vivo experiments in five healthy term newborn lambs have demonstrated that it was efficient to generate expiratory flows while avoiding collapses. Moreover, the in vivo results have demonstrated that our liquid ventilator can maintain adequate gas exchange, normal acid-base equilibrium, and achieve greater minute ventilation, better oxygenation and CO2 extraction, while nearing flow limits. Hence, it is our suggestion to perform pressure-controlled ventilation during expiration with minute ventilation equal or superior to 140 mL x min(-1) x kg(-1) in order to ensure PaCO2 below 55 mmHg. From a clinician's point of view, pressure-controlled ventilation greatly simplifies the use of the liquid ventilator, which will certainly facilitate its introduction in intensive care units for clinical applications.

  8. Integrated energy system for a high performance building

    NASA Astrophysics Data System (ADS)

    Jaczko, Kristen

    Integrated energy systems have the potential to reduce of the energy consumption of residential buildings in Canada. These systems incorporate components to meet the building heating, cooling and domestic hot water load into a single system in order to reduce energy losses. An integrated energy system, consisting of a variable speed heat pump, cold and hot thermal storage tanks, a photovoltaic/thermal (PV/T) collector array and a battery bank, was designed for the Queen's Solar Design Team's (QSDT) test house. The system uses a radiant floor to provide space- heating and sensible cooling and a dedicated outdoor air system provides ventilation and dehumidifies the incoming fresh air. The test house, the Queen's Solar Education Centre (QSEC), and the integrated energy system were both modelled in TRNSYS. Additionally, a new TRNSYS Type was developed to model the PV/T collectors, enabling the modeling of the collection of energy from the ambient air. A parametric study was carried out in TRNSYS to investigate the effect of various parameters on the overall energy performance of the system. These parameters included the PV/T array size and the slope of the collectors, the heat pump source and load-side inlet temperature setpoints, the compressor speed control and the size of the thermal storage tanks and the battery bank. The controls of the heat pump were found to have a large impact on the performance of the integrated energy system. For example, a low evaporator setpoint improved the overall free energy ratio (FER) of the system but the heat pump performance was lowered. Reducing the heat loss of the PV/T panels was not found to have a large effect on the system performance however, as the heat pump is able to lower the inlet collector fluid temperature, thus reducing thermal losses. From the results of the sensitivity study, a recommended system model was created and this system had a predicted FER of 77.9% in Kingston, Ontario, neglecting the energy consumption of circulation pumps and fans. Simulations of the recommended integrated energy system were also performed in several other Canadian cities and the predicted FER was above 60% in all except for the most northern city investigated, Yellowknife. Thus, the integrated energy system has the potential of reducing the energy consumption of residential buildings in Canada.

  9. Ventilation practices in the neonatal intensive care unit: a cross-sectional study.

    PubMed

    van Kaam, Anton H; Rimensberger, Peter C; Borensztajn, Dorine; De Jaegere, Anne P

    2010-11-01

    To assess current ventilation practices in newborn infants. We conducted a 2-point cross-sectional study in 173 European neonatal intensive care units, including 535 infants (mean gestational age 28 weeks and birth weight 1024 g). Patient characteristics, ventilator settings, and measurements were collected bedside from endotracheally ventilated infants. A total of 457 (85%) patients were conventionally ventilated. Time cycled pressure-limited ventilation was used in 59% of these patients, most often combined with synchronized intermittent mandatory ventilation (51%). Newer conventional ventilation modes like volume targeted and pressure support ventilation were used in, respectively, 9% and 7% of the patients. The mean tidal volume, measured in 84% of the conventionally ventilated patients, was 5.7 ± 2.3 ml/kg. The mean positive end-expiratory pressure was 4.5 ± 1.1 cmH(2)O and rarely exceeded 7 cmH(2)O. Time cycled pressure-limited ventilation is the most commonly used mode in neonatal ventilation. Tidal volumes are usually targeted between 4 to 7 mL/kg and positive end-expiratory pressure between 4 to 6 cmH(2)O. Newer ventilation modes are only used in a minority of patients. Copyright © 2010 Mosby, Inc. All rights reserved.

  10. Differential lung ventilation via tracheostomy using two endotracheal tubes in an infant: a case report.

    PubMed

    Demirkol, Demet; Ataman, Yasemin; Gündoğdu, Gökhan

    2017-09-08

    This case report presents differential lung ventilation in an infant. The aim is to define an alternative technique for performing differential lung ventilation in children. To the best of our knowledge, this is the first report of this kind. A 4.2-kg, 2.5-month-old Asian boy was referred to our facility with refractory hypoxemia and hypercarbia due to asymmetric lung disease with atelectasis of the left lung and hyperinflation of the right lung. He was unresponsive to conventional ventilator strategies; different ventilator settings were required. To perform differential lung ventilation, two separate single-lumen endotracheal tubes were inserted into the main bronchus of each lung by tracheotomy; the tracheal tubes were attached to discrete ventilators. The left lung was ventilated with a lung salvage strategy using high-frequency oscillatory ventilation, and the right lung was ventilated with a lung-protective strategy using pressure-regulated volume control mode. Differential lung ventilation was performed successfully with this technique without complications. Differential lung ventilation may be a lifesaving procedure in select patients who have asymmetric lung disease. Inserting two single-lumen endotracheal tubes via tracheotomy for differential lung ventilation can be an effective and safe alternative method.

  11. Effect of one-lung ventilation on end-tidal carbon dioxide during cardiopulmonary resuscitation in a pig model of cardiac arrest.

    PubMed

    Ryu, Dong Hyun; Jung, Yong Hun; Jeung, Kyung Woon; Lee, Byung Kook; Jeong, Young Won; Yun, Jong Geun; Lee, Dong Hun; Lee, Sung Min; Heo, Tag; Min, Yong Il

    2018-01-01

    Unrecognized endobronchial intubation frequently occurs after emergency intubation. However, no study has evaluated the effect of one-lung ventilation on end-tidal carbon dioxide (ETCO2) during cardiopulmonary resuscitation (CPR). We compared the hemodynamic parameters, blood gases, and ETCO2 during one-lung ventilation with those during conventional two-lung ventilation in a pig model of CPR, to determine the effect of the former on ETCO2. A randomized crossover study was conducted in 12 pigs intubated with double-lumen endobronchial tube to achieve lung separation. During CPR, the animals underwent three 5-min ventilation trials based on a randomized crossover design: left-lung, right-lung, or two-lung ventilation. Arterial blood gases were measured at the end of each ventilation trial. Ventilation was provided using the same tidal volume throughout the ventilation trials. Comparison using generalized linear mixed model revealed no significant group effects with respect to aortic pressure, coronary perfusion pressure, and carotid blood flow; however, significant group effect in terms of ETCO2 was found (P < 0.001). In the post hoc analyses, ETCO2 was lower during the right-lung ventilation than during the two-lung (P = 0.006) or left-lung ventilation (P < 0.001). However, no difference in ETCO2 was detected between the left-lung and two-lung ventilations. The partial pressure of arterial carbon dioxide (PaCO2), partial pressure of arterial oxygen (PaO2), and oxygen saturation (SaO2) differed among the three types of ventilation (P = 0.003, P = 0.001, and P = 0.001, respectively). The post hoc analyses revealed a higher PaCO2, lower PaO2, and lower SaO2 during right-lung ventilation than during two-lung or left-lung ventilation. However, the levels of these blood gases did not differ between the left-lung and two-lung ventilations. In a pig model of CPR, ETCO2 was significantly lower during right-lung ventilation than during two-lung ventilation. However, interestingly, ETCO2 during left-lung ventilation was comparable to that during two-lung ventilation.

  12. Protective mechanical ventilation in United Kingdom critical care units: A multicentre audit

    PubMed Central

    Martin, Matthew J; Richardson, Neil; Bourdeaux, Christopher P

    2016-01-01

    Lung protective ventilation is becoming increasingly used for all critically ill patients being mechanically ventilated on a mandatory ventilator mode. Compliance with the universal application of this ventilation strategy in intensive care units in the United Kingdom is unknown. This 24-h audit of ventilation practice took place in 16 intensive care units in two regions of the United Kingdom. The mean tidal volume for all patients being ventilated on a mandatory ventilator mode was 7.2(±1.4) ml kg−1 predicted body weight and overall compliance with low tidal volume ventilation (≤6.5 ml kg−1 predicted body weight) was 34%. The mean tidal volume for patients ventilated with volume-controlled ventilation was 7.0(±1.2) ml kg−1 predicted body weight and 7.9(±1.8) ml kg−1 predicted body weight for pressure-controlled ventilation (P < 0.0001). Overall compliance with recommended levels of positive end-expiratory pressure was 72%. Significant variation in practice existed both at a regional and individual unit level. PMID:28979556

  13. Protective mechanical ventilation in United Kingdom critical care units: A multicentre audit.

    PubMed

    Newell, Christopher P; Martin, Matthew J; Richardson, Neil; Bourdeaux, Christopher P

    2017-05-01

    Lung protective ventilation is becoming increasingly used for all critically ill patients being mechanically ventilated on a mandatory ventilator mode. Compliance with the universal application of this ventilation strategy in intensive care units in the United Kingdom is unknown. This 24-h audit of ventilation practice took place in 16 intensive care units in two regions of the United Kingdom. The mean tidal volume for all patients being ventilated on a mandatory ventilator mode was 7.2(±1.4) ml kg -1 predicted body weight and overall compliance with low tidal volume ventilation (≤6.5 ml kg -1 predicted body weight) was 34%. The mean tidal volume for patients ventilated with volume-controlled ventilation was 7.0(±1.2) ml kg -1 predicted body weight and 7.9(±1.8) ml kg -1 predicted body weight for pressure-controlled ventilation ( P  < 0.0001). Overall compliance with recommended levels of positive end-expiratory pressure was 72%. Significant variation in practice existed both at a regional and individual unit level.

  14. Clinical challenges in mechanical ventilation.

    PubMed

    Goligher, Ewan C; Ferguson, Niall D; Brochard, Laurent J

    2016-04-30

    Mechanical ventilation supports gas exchange and alleviates the work of breathing when the respiratory muscles are overwhelmed by an acute pulmonary or systemic insult. Although mechanical ventilation is not generally considered a treatment for acute respiratory failure per se, ventilator management warrants close attention because inappropriate ventilation can result in injury to the lungs or respiratory muscles and worsen morbidity and mortality. Key clinical challenges include averting intubation in patients with respiratory failure with non-invasive techniques for respiratory support; delivering lung-protective ventilation to prevent ventilator-induced lung injury; maintaining adequate gas exchange in severely hypoxaemic patients; avoiding the development of ventilator-induced diaphragm dysfunction; and diagnosing and treating the many pathophysiological mechanisms that impair liberation from mechanical ventilation. Personalisation of mechanical ventilation based on individual physiological characteristics and responses to therapy can further improve outcomes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Improved oxygenation 24 hours after transition to airway pressure release ventilation or high-frequency oscillatory ventilation accurately discriminates survival in immunocompromised pediatric patients with acute respiratory distress syndrome*.

    PubMed

    Yehya, Nadir; Topjian, Alexis A; Thomas, Neal J; Friess, Stuart H

    2014-05-01

    Children with an immunocompromised condition and requiring invasive mechanical ventilation have high risk of death. Such patients are commonly transitioned to rescue modes of nonconventional ventilation, including airway pressure release ventilation and high-frequency oscillatory ventilation, for acute respiratory distress syndrome refractory to conventional ventilation. Our aim was to describe our experience with airway pressure release ventilation and high-frequency oscillatory ventilation in children with an immunocompromised condition and acute respiratory distress syndrome refractory to conventional ventilation and to identify factors associated with survival. Retrospective cohort study. Tertiary care, university-affiliated PICU. Sixty pediatric patients with an immunocompromised condition and acute respiratory distress syndrome refractory to conventional ventilation transitioned to either airway pressure release ventilation or high-frequency oscillatory ventilation. None. Demographic data, ventilator settings, arterial blood gases, oxygenation index, and PaO(2)/FIO(2) were recorded before transition to either mode of nonconventional ventilation and at predetermined intervals after transition for up to 5 days. Mortality in the entire cohort was 63% and did not differ between patients transitioned to airway pressure release ventilation and high-frequency oscillatory ventilation. For both airway pressure release ventilation and high-frequency oscillatory ventilation, improvements in oxygenation index and PaO(2)/FIO(2) at 24 hours expressed as a fraction of pretransition values (oxygenation index(24)/oxygenation index(pre) and PaO(2)/FIO(224)/PaO(2)/FIO(2pre)) reliably discriminated nonsurvivors from survivors, with receiver operating characteristic areas under the curves between 0.89 and 0.95 (p for all curves < 0.001). Sensitivity-specificity analysis suggested that less than 15% reduction in oxygenation index (90% sensitive, 75% specific) or less than 90% increase in PaO(2)/FIO(2) (80% sensitive, 94% specific) 24 hours after transition to airway pressure release ventilation were the optimal cutoffs to identify nonsurvivors. The comparable values 24 hours after transition to high-frequency oscillatory ventilation were less than 5% reduction in oxygenation index (100% sensitive, 83% specific) or less than 80% increase in PaO(2)/FIO(2) (91% sensitive, 89% specific) to identify nonsurvivors. In this single-center retrospective study of pediatric patients with an immunocompromised condition and acute respiratory distress syndrome failing conventional ventilation transitioned to either airway pressure release ventilation or high-frequency oscillatory ventilation, improved oxygenation at 24 hours expressed as PaO(2)/FIO(224)/PaO(2)/FIO(2pre) or oxygenation index(24)/oxygenation indexpre reliably discriminates nonsurvivors from survivors. These findings should be prospectively verified.

  16. GENERAL VIEW SHOWING VENTILATOR NUMBER NINE. THIS VENTILATOR IS SLIGHTLY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    GENERAL VIEW SHOWING VENTILATOR NUMBER NINE. THIS VENTILATOR IS SLIGHTLY MORE ORNATE THAN WAS GENERALLY USED BECAUSE OF ITS LOCATION - Old Croton Aqueduct, Ventilator Number 9, Spring & Everett Streets, Ossining, Westchester County, NY

  17. Clinical Validation of 4-Dimensional Computed Tomography Ventilation With Pulmonary Function Test Data

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Brennan, Douglas; Schubert, Leah; Diot, Quentin

    Purpose: A new form of functional imaging has been proposed in the form of 4-dimensional computed tomography (4DCT) ventilation. Because 4DCTs are acquired as part of routine care for lung cancer patients, calculating ventilation maps from 4DCTs provides spatial lung function information without added dosimetric or monetary cost to the patient. Before 4DCT-ventilation is implemented it needs to be clinically validated. Pulmonary function tests (PFTs) provide a clinically established way of evaluating lung function. The purpose of our work was to perform a clinical validation by comparing 4DCT-ventilation metrics with PFT data. Methods and Materials: Ninety-eight lung cancer patients withmore » pretreatment 4DCT and PFT data were included in the study. Pulmonary function test metrics used to diagnose obstructive lung disease were recorded: forced expiratory volume in 1 second (FEV1) and FEV1/forced vital capacity. Four-dimensional CT data sets and spatial registration were used to compute 4DCT-ventilation images using a density change–based and a Jacobian-based model. The ventilation maps were reduced to single metrics intended to reflect the degree of ventilation obstruction. Specifically, we computed the coefficient of variation (SD/mean), ventilation V20 (volume of lung ≤20% ventilation), and correlated the ventilation metrics with PFT data. Regression analysis was used to determine whether 4DCT ventilation data could predict for normal versus abnormal lung function using PFT thresholds. Results: Correlation coefficients comparing 4DCT-ventilation with PFT data ranged from 0.63 to 0.72, with the best agreement between FEV1 and coefficient of variation. Four-dimensional CT ventilation metrics were able to significantly delineate between clinically normal versus abnormal PFT results. Conclusions: Validation of 4DCT ventilation with clinically relevant metrics is essential. We demonstrate good global agreement between PFTs and 4DCT-ventilation, indicating that 4DCT-ventilation provides a reliable assessment of lung function. Four-dimensional CT ventilation enables exciting opportunities to assess lung function and create functional avoidance radiation therapy plans. The present work provides supporting evidence for the integration of 4DCT-ventilation into clinical trials.« less

  18. SU-F-J-219: Predicting Ventilation Change Due to Radiation Therapy: Dependency On Pre-RT Ventilation and Effort Correction

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Patton, T; Du, K; Bayouth, J

    Purpose: Ventilation change caused by radiation therapy (RT) can be predicted using four-dimensional computed tomography (4DCT) and image registration. This study tested the dependency of predicted post-RT ventilation on effort correction and pre-RT lung function. Methods: Pre-RT and 3 month post-RT 4DCT images were obtained for 13 patients. The 4DCT images were used to create ventilation maps using a deformable image registration based Jacobian expansion calculation. The post-RT ventilation maps were predicted in four different ways using the dose delivered, pre-RT ventilation, and effort correction. The pre-RT ventilation and effort correction were toggled to determine dependency. The four different predictedmore » ventilation maps were compared to the post-RT ventilation map calculated from image registration to establish the best prediction method. Gamma pass rates were used to compare the different maps with the criteria of 2mm distance-to-agreement and 6% ventilation difference. Paired t-tests of gamma pass rates were used to determine significant differences between the maps. Additional gamma pass rates were calculated using only voxels receiving over 20 Gy. Results: The predicted post-RT ventilation maps were in agreement with the actual post-RT maps in the following percentage of voxels averaged over all subjects: 71% with pre-RT ventilation and effort correction, 69% with no pre-RT ventilation and effort correction, 60% with pre-RT ventilation and no effort correction, and 58% with no pre-RT ventilation and no effort correction. When analyzing only voxels receiving over 20 Gy, the gamma pass rates were respectively 74%, 69%, 65%, and 55%. The prediction including both pre- RT ventilation and effort correction was the only prediction with significant improvement over using no prediction (p<0.02). Conclusion: Post-RT ventilation is best predicted using both pre-RT ventilation and effort correction. This is the only prediction that provided a significant improvement on agreement. Research support from NIH grants CA166119 and CA166703, a gift from Roger Koch, and a Pilot Grant from University of Iowa Carver College of Medicine.« less

  19. Adaptive support ventilation may deliver unwanted respiratory rate-tidal volume combinations in patients with acute lung injury ventilated according to an open lung concept.

    PubMed

    Dongelmans, Dave A; Paulus, Frederique; Veelo, Denise P; Binnekade, Jan M; Vroom, Margreeth B; Schultz, Marcus J

    2011-05-01

    With adaptive support ventilation, respiratory rate and tidal volume (V(T)) are a function of the Otis least work of breathing formula. We hypothesized that adaptive support ventilation in an open lung ventilator strategy would deliver higher V(T)s to patients with acute lung injury. Patients with acute lung injury were ventilated according to a local guideline advising the use of lower V(T) (6-8 ml/kg predicted body weight), high concentrations of positive end-expiratory pressure, and recruitment maneuvers. Ventilation parameters were recorded when the ventilator was switched to adaptive support ventilation, and after recruitment maneuvers. If V(T) increased more than 8 ml/kg predicted body weight, airway pressure was limited to correct for the rise of V(T). Ten patients with a mean (±SD) Pao(2)/Fio(2) of 171 ± 86 mmHg were included. After a switch from pressure-controlled ventilation to adaptive support ventilation, respiratory rate declined (from 31 ± 5 to 21 ± 6 breaths/min; difference = 10 breaths/min, 95% CI 3-17 breaths/min, P = 0.008) and V(T) increased (from 6.5 ± 0.8 to 9.0 ± 1.6 ml/kg predicted body weight; difference = 2.5 ml, 95% CI 0.4-4.6 ml/kg predicted body weight, P = 0.02). Pressure limitation corrected for the rise of V(T), but minute ventilation declined, forcing the user to switch back to pressure-controlled ventilation. Adaptive support ventilation, compared with pressure-controlled ventilation in an open lung strategy setting, delivers a lower respiratory rate-higher V(T) combination. Pressure limitation does correct for the rise of V(T), but leads to a decline in minute ventilation.

  20. Analysis of radon reduction and ventilation systems in uranium mines in China.

    PubMed

    Hu, Peng-hua; Li, Xian-jie

    2012-09-01

    Mine ventilation is the most important way of reducing radon in uranium mines. At present, the radon and radon progeny levels in Chinese uranium mines where the cut and fill stoping method is used are 3-5 times higher than those in foreign uranium mines, as there is not much difference in the investments for ventilation protection between Chinese uranium mines and international advanced uranium mines with compaction methodology. In this paper, through the analysis of radon reduction and ventilation systems in Chinese uranium mines and the comparison of advantages and disadvantages between a variety of ventilation systems in terms of radon control, the authors try to illustrate the reasons for the higher radon and radon progeny levels in Chinese uranium mines and put forward some problems in three areas, namely the theory of radon control and ventilation systems, radon reduction ventilation measures and ventilation management. For these problems, this paper puts forward some proposals regarding some aspects, such as strengthening scrutiny, verifying and monitoring the practical situation, making clear ventilation plans, strictly following the mining sequence, promoting training of ventilation staff, enhancing ventilation system management, developing radon reduction ventilation technology, purchasing ventilation equipment as soon as possible in the future, and so on.

  1. Physiological Responses During Multiplay Exergaming in Young Adult Males are Game-Dependent

    PubMed Central

    McGuire, Stephen; Willems, Mark ET

    2015-01-01

    Regular moderate-intensity exercise provides health benefits. The aim of this study was to examine whether the selected exercise intensity and physiological responses during exergaming in a single and multiplayer mode in the same physical space were game-dependent. Ten males (mean ±SD, age: 23 ±5 years, body mass: 84.2 ±15.6 kg, body height: 180 ±7 cm, body mass index: 26.0 ±4.0 kg·m−2) played the games Kinect football, boxing and track & field (3 × ∼10 min, ∼ 2 min rest periods) in similar time sequence in two sessions. Physiological responses were measured with the portable Cosmed K4b2 pulmonary gas exchange system. Single play demands were used to match with a competitive opponent in a multiplay mode. A within-subjects crossover design was used with one-way ANOVA and a post-hoc t-test for analysis (p<0.05). Minute ventilation, oxygen uptake and the heart rate were at least 18% higher during a multiplayer mode for Kinect football and boxing but not for track & field. Energy expenditure was 21% higher during multiplay football. Single play track & field had higher metabolic equivalent than single play football (5.7 ±1.6, range: 3.2–8.6 vs 4.1 ±1.0, range: 3.0–6.1, p<0.05). Exergaming in a multiplayer mode can provide higher physiological demands but the effects are game-dependent. It seems that exergaming with low intensity in a multiplayer mode may provide a greater physical challenge for participants than in a single play mode but may not consistently provide sufficient intensity to acquire health benefits when played regularly as part of a programme to promote and maintain health in young adults. PMID:26240669

  2. 1. GENERAL VIEW SHOWING VENTILATOR NO. 9. THIS VENTILATOR IS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. GENERAL VIEW SHOWING VENTILATOR NO. 9. THIS VENTILATOR IS SLIGHTLY MORE ORNATE THAN WAS GENERALLY USED BECAUSE OF ITS LOCATION. - Old Croton Aqueduct, Ventilator Number 9, Spring & Everett Streets, Ossining, Westchester County, NY

  3. Optimal ventilation of the anesthetized pediatric patient.

    PubMed

    Feldman, Jeffrey M

    2015-01-01

    Mechanical ventilation of the pediatric patient is challenging because small changes in delivered volume can be a significant fraction of the intended tidal volume. Anesthesia ventilators have traditionally been poorly suited to delivering small tidal volumes accurately, and pressure-controlled ventilation has become used commonly when caring for pediatric patients. Modern anesthesia ventilators are designed to deliver small volumes accurately to the patient's airway by compensating for the compliance of the breathing system and delivering tidal volume independent of fresh gas flow. These technology advances provide the opportunity to implement a lung-protective ventilation strategy in the operating room based upon control of tidal volume. This review will describe the capabilities of the modern anesthesia ventilator and the current understanding of lung-protective ventilation. An optimal approach to mechanical ventilation for the pediatric patient is described, emphasizing the importance of using bedside monitors to optimize the ventilation strategy for the individual patient.

  4. 46 CFR 32.60-20 - Pumprooms on tank vessels carrying Grade A, B, C, D and/or E liquid cargo-TB/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    .... Ventilation from the weather deck shall be provided. Power supply ventilation may be fitted in lieu of natural... not exceed 500 °F. (b) Ventilation for pumprooms on tank vessels the construction or conversion of... with power ventilation. Pumprooms equipped with power ventilation shall have the ventilation outlets...

  5. Effect of flashlight guidance on manual ventilation performance in cardiopulmonary resuscitation: A randomized controlled simulation study.

    PubMed

    Kim, Ji Hoon; Beom, Jin Ho; You, Je Sung; Cho, Junho; Min, In Kyung; Chung, Hyun Soo

    2018-01-01

    Several auditory-based feedback devices have been developed to improve the quality of ventilation performance during cardiopulmonary resuscitation (CPR), but their effectiveness has not been proven in actual CPR situations. In the present study, we investigated the effectiveness of visual flashlight guidance in maintaining high-quality ventilation performance. We conducted a simulation-based, randomized, parallel trial including 121 senior medical students. All participants were randomized to perform ventilation during 2 minutes of CPR with or without flashlight guidance. For each participant, we measured mean ventilation rate as a primary outcome and ventilation volume, inspiration velocity, and ventilation interval as secondary outcomes using a computerized device system. Mean ventilation rate did not significantly differ between flashlight guidance and control groups (P = 0.159), but participants in the flashlight guidance group exhibited significantly less variation in ventilation rate than participants in the control group (P<0.001). Ventilation interval was also more regular among participants in the flashlight guidance group. Our results demonstrate that flashlight guidance is effective in maintaining a constant ventilation rate and interval. If confirmed by further studies in clinical practice, flashlight guidance could be expected to improve the quality of ventilation performed during CPR.

  6. Effects of Multiple Ventilation Courses and Duration of Mechanical Ventilation on Respiratory Outcomes in Extremely Low-Birth-Weight Infants.

    PubMed

    Jensen, Erik A; DeMauro, Sara B; Kornhauser, Michael; Aghai, Zubair H; Greenspan, Jay S; Dysart, Kevin C

    2015-11-01

    Extubation failure is common in extremely preterm infants. The current paucity of data on the adverse long-term respiratory outcomes associated with reinitiation of mechanical ventilation prevents assessment of the risks and benefits of a trial of extubation in this population. To evaluate whether exposure to multiple courses of mechanical ventilation increases the risk of adverse respiratory outcomes before and after adjustment for the cumulative duration of mechanical ventilation. We performed a retrospective cohort study of extremely low-birth-weight (ELBW; birth weight <1000 g) infants born from January 1, 2006, through December 31, 2012, who were receiving mechanical ventilation. Analysis was conducted between November 2014 and February 2015. Data were obtained from the Alere Neonatal Database. The primary study exposures were the cumulative duration of mechanical ventilation and the number of ventilation courses. The primary outcome was bronchopulmonary dysplasia (BPD) among survivors. Secondary outcomes were death, use of supplemental oxygen at discharge, and tracheostomy. We identified 3343 ELBW infants, of whom 2867 (85.8%) survived to discharge. Among the survivors, 1695 (59.1%) were diagnosed as having BPD, 856 (29.9%) received supplemental oxygen at discharge, and 31 (1.1%) underwent tracheostomy. Exposure to a greater number of mechanical ventilation courses was associated with a progressive increase in the risk of BPD and use of supplemental oxygen at discharge. Compared with a single ventilation course, the adjusted odds ratios for BPD ranged from 1.88 (95% CI, 1.54-2.31) among infants with 2 ventilation courses to 3.81 (95% CI, 2.88-5.04) among those with 4 or more courses. After adjustment for the cumulative duration of mechanical ventilation, the odds of BPD were only increased among infants exposed to 4 or more ventilation courses (adjusted odds ratio, 1.44; 95% CI, 1.04-2.01). The number of ventilation courses was not associated with increased risk of supplemental oxygen use at discharge after adjustment for the length of ventilation. A greater number of ventilation courses did not increase the risk of tracheostomy. Among ELBW infants, a longer cumulative duration of mechanical ventilation largely accounts for the increased risk of chronic respiratory morbidity associated with reinitiation of mechanical ventilation. These results support attempts of extubation in ELBW infants receiving mechanical ventilation on low ventilator settings, even when success is not guaranteed.

  7. Aerosol delivery with two ventilation modes during mechanical ventilation: a randomized study.

    PubMed

    Dugernier, Jonathan; Reychler, Gregory; Wittebole, Xavier; Roeseler, Jean; Depoortere, Virginie; Sottiaux, Thierry; Michotte, Jean-Bernard; Vanbever, Rita; Dugernier, Thierry; Goffette, Pierre; Docquier, Marie-Agnes; Raftopoulos, Christian; Hantson, Philippe; Jamar, François; Laterre, Pierre-François

    2016-12-01

    Volume-controlled ventilation has been suggested to optimize lung deposition during nebulization although promoting spontaneous ventilation is targeted to avoid ventilator-induced diaphragmatic dysfunction. Comparing topographic aerosol lung deposition during volume-controlled ventilation and spontaneous ventilation in pressure support has never been performed. The aim of this study was to compare lung deposition of a radiolabeled aerosol generated with a vibrating-mesh nebulizer during invasive mechanical ventilation, with two modes: pressure support ventilation and volume-controlled ventilation. Seventeen postoperative neurosurgery patients without pulmonary disease were randomly ventilated in pressure support or volume-controlled ventilation. Diethylenetriaminepentaacetic acid labeled with technetium-99m (2 mCi/3 mL) was administrated using a vibrating-mesh nebulizer (Aerogen Solo(®), provided by Aerogen Ltd, Galway, Ireland) connected to the endotracheal tube. Pulmonary and extrapulmonary particles deposition was analyzed using planar scintigraphy. Lung deposition was 10.5 ± 3.0 and 15.1 ± 5.0 % of the nominal dose during pressure support and volume-controlled ventilation, respectively (p < 0.05). Higher endotracheal tube and tracheal deposition was observed during pressure support ventilation (27.4 ± 6.6 vs. 20.7 ± 6.0 %, p < 0.05). A similar penetration index was observed for the right (p = 0.210) and the left lung (p = 0.211) with both ventilation modes. A high intersubject variability of lung deposition was observed with both modes regarding lung doses, aerosol penetration and distribution between the right and the left lung. In the specific conditions of the study, volume-controlled ventilation was associated with higher lung deposition of nebulized particles as compared to pressure support ventilation. The clinical benefit of this effect warrants further studies. Clinical trial registration NCT01879488.

  8. Association Between Noninvasive Ventilation and Mortality Among Older Patients With Pneumonia

    PubMed Central

    Valley, Thomas S.; Walkey, Allan J.; Lindenauer, Peter K.; Wiener, Renda Soylemez; Cooke, Colin R.

    2016-01-01

    Objective Despite increasing use, evidence is mixed as to the appropriate use of noninvasive ventilation in patients with pneumonia. We aimed to determine the relationship between receipt of noninvasive ventilation and outcomes for patients with pneumonia in a real-world setting. Design, Setting, Patients We performed a retrospective cohort study of Medicare beneficiaries (aged > 64 yr) admitted to 2,757 acute-care hospitals in the United States with pneumonia, who received mechanical ventilation from 2010 to 2011. Exposures Noninvasive ventilation versus invasive mechanical ventilation. Measurement and Main Results The primary outcome was 30-day mortality with Medicare reimbursement as a secondary outcome. To account for unmeasured confounding associated with noninvasive ventilation use, an instrumental variable was used—the differential distance to a high noninvasive ventilation use hospital. All models were adjusted for patient and hospital characteristics to account for measured differences between groups. Among 65,747 Medicare beneficiaries with pneumonia who required mechanical ventilation, 12,480 (19%) received noninvasive ventilation. Patients receiving noninvasive ventilation were more likely to be older, male, white, rural-dwelling, have fewer comorbidities, and were less likely to be acutely ill as measured by organ failures. Results of the instrumental variable analysis suggested that, among marginal patients, receipt of noninvasive ventilation was not significantly associated with differences in 30-day mortality when compared with invasive mechanical ventilation (54% vs 55%; p = 0.92; 95% CI of absolute difference, –13.8 to 12.4) but was associated with significantly lower Medicare spending ($18,433 vs $27,051; p = 0.02). Conclusions Among Medicare beneficiaries hospitalized with pneumonia who received mechanical ventilation, noninvasive ventilation use was not associated with a real-world mortality benefit. Given the wide CIs, however, substantial harm associated with noninvasive ventilation could not be excluded. The use of noninvasive ventilation for patients with pneumonia should be cautioned, but targeted enrollment of marginal patients with pneumonia could enrich future randomized trials. PMID:27749319

  9. The effect of helium on ventilator performance: study of five ventilators and a bedside Pitot tube spirometer.

    PubMed

    Oppenheim-Eden, A; Cohen, Y; Weissman, C; Pizov, R

    2001-08-01

    To assess in vitro the performance of five mechanical ventilators-Siemens 300 and 900C (Siemens-Elma; Solna, Sweden), Puritan Bennett 7200 (Nellcor Puritan Bennett; Pleasanton, CA), Evita 4 (Dragerwerk; Lubeck, Germany), and Bear 1000 (Bear Medical Systems; Riverside CA)-and a bedside sidestream spirometer (Datex CS3 Respiratory Module; Datex-Ohmeda; Helsinki, Finland) during ventilation with helium-oxygen mixtures. In vitro study. ICUs of two university-affiliated hospitals. Each ventilator was connected to 100% helium through compressed air inlets and then tested at three to six different tidal volume (VT) settings using various helium-oxygen concentrations (fraction of inspired oxygen [FIO(2)] of 0.2 to 1.0). FIO(2) and VT were measured with the Datex CS3 spirometer, and VT was validated with a water-displacement spirometer. The Puritan Bennett 7200 ventilator did not function with helium. With the other four ventilators, delivered FIO(2) was lower than the set FIO(2). For the Siemens 300 and 900C ventilators, this difference could be explained by the lack of 21% oxygen when helium was connected to the air supply port, while for the other two ventilators, a nonlinear relation was found. The VT of the Siemens 300 ventilator was independent of helium concentration, while for the other three ventilators, delivered VT was greater than the set VT and was dependent on helium concentration. During ventilation with 80% helium and 20% oxygen, VT increased to 125% of set VT for the Siemens 900C ventilator, and more than doubled for the Evita 4 and Bear 1000 ventilators. Under the same conditions, the Datex CS3 spirometer underestimated the delivered VT by about 33%. At present, no mechanical ventilator is calibrated for use with helium. This investigation offers correction factors for four ventilators for ventilation with helium.

  10. Bench performance of ventilators during simulated paediatric ventilation.

    PubMed

    Park, M A J; Freebairn, R C; Gomersall, C D

    2013-05-01

    This study compares the accuracy and capabilities of various ventilators using a paediatric acute respiratory distress syndrome lung model. Various compliance settings and respiratory rate settings were used. The study was done in three parts: tidal volume and FiO2 accuracy; pressure control accuracy and positive end-expiratory pressure (PEEP) accuracy. The parameters set on the ventilator were compared with either or both of the measured parameters by the test lung and the ventilator. The results revealed that none of the ventilators could consistently deliver tidal volumes within 1 ml/kg of the set tidal volume, and the discrepancy between the delivered volume and the volume measured by the ventilator varied greatly. The target tidal volume was 8 ml/kg, but delivered tidal volumes ranged from 3.6-11.4 ml/kg and the volumes measured by the ventilator ranged from 4.1-20.6 ml/kg. All the ventilators maintained pressure within 20% of the set pressure, except one ventilator which delivered pressures of up to 27% higher than the set pressure. Two ventilators maintained PEEP within 10% of the prescribed PEEP. The majority of the readings were also within 10%. However, three ventilators delivered, at times, PEEPs over 20% higher. In conclusion, as lung compliance decreases, especially in paediatric patients, some ventilators perform better than others. This study highlights situations where ventilators may not be able to deliver, nor adequately measure, set tidal volumes, pressure, PEEP or FiO2.

  11. Significant Improvements in Pyranometer Nighttime Offsets Using High-Flow DC Ventilation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Michalsky, Joseph J.; Kutchenreiter, Mark; Long, Charles N.

    Ventilators are used to keep the domes of pyranometers clean and dry, but they affect the nighttime offset as well. This paper examines different ventilation strategies. For the several commercial single-black-detector pyranometers with ventilators examined here, high flow rate (50 CFM and higher), 12 VDC fans lower the offsets, lower the scatter, and improve the predictability of the offsets during the night compared with lower flow rate 35 CFM, 120 VAC fans operated in the same ventilator housings. Black-and-white pyranometers sometimes show improvement with DC ventilation, but in some cases DC ventilation makes the offsets slightly worse. Since the offsetsmore » for these black-and-white pyranometers are always small, usually no more than 1 Wm -2, whether AC or DC ventilated, changing their ventilation to higher CFM DC ventilation is not imperative. Future work should include all major manufacturers of pyranometers and unventilated, as well as, ventilated pyranometers. Lastly, an important outcome of future research will be to clarify under what circumstances nighttime data can be used to predict daytime offsets.« less

  12. Using a Ventilation Controller to Optimize Residential Passive Ventilation For Energy and Indoor Air Quality

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Turner, William; Walker, Iain

    One way to reduce the energy impact of providing residential ventilation is to use passive and hybrid systems. However, these passive and hybrid (sometimes called mixed-mode) systems must still meet chronic and acute health standards for ventilation. This study uses a computer simulation approach to examine the energy and indoor air quality (IAQ) implications of passive and hybrid ventilation systems, in 16 California climate zones. Both uncontrolled and flow controlled passive stacks are assessed. A new hybrid ventilation system is outlined that uses an intelligent ventilation controller to minimise energy use, while ensuring chronic and acute IAQ standards are met.more » ASHRAE Standard 62.2-2010 – the United States standard for residential ventilation - is used as the chronic standard, and exposure limits for PM 2.5, formaldehyde and NO 2 are used as the acute standards.The results show that controlled passive ventilation and hybrid ventilation can be used in homes to provide equivalent IAQ to continuous mechanical ventilation, for less use of energy.« less

  13. Significant Improvements in Pyranometer Nighttime Offsets Using High-Flow DC Ventilation

    DOE PAGES

    Michalsky, Joseph J.; Kutchenreiter, Mark; Long, Charles N.

    2017-06-20

    Ventilators are used to keep the domes of pyranometers clean and dry, but they affect the nighttime offset as well. This paper examines different ventilation strategies. For the several commercial single-black-detector pyranometers with ventilators examined here, high flow rate (50 CFM and higher), 12 VDC fans lower the offsets, lower the scatter, and improve the predictability of the offsets during the night compared with lower flow rate 35 CFM, 120 VAC fans operated in the same ventilator housings. Black-and-white pyranometers sometimes show improvement with DC ventilation, but in some cases DC ventilation makes the offsets slightly worse. Since the offsetsmore » for these black-and-white pyranometers are always small, usually no more than 1 Wm -2, whether AC or DC ventilated, changing their ventilation to higher CFM DC ventilation is not imperative. Future work should include all major manufacturers of pyranometers and unventilated, as well as, ventilated pyranometers. Lastly, an important outcome of future research will be to clarify under what circumstances nighttime data can be used to predict daytime offsets.« less

  14. Economic, Environmental and Health Implications of Enhanced Ventilation in Office Buildings.

    PubMed

    MacNaughton, Piers; Pegues, James; Satish, Usha; Santanam, Suresh; Spengler, John; Allen, Joseph

    2015-11-18

    Current building ventilation standards are based on acceptable minimums. Three decades of research demonstrates the human health benefits of increased ventilation above these minimums. Recent research also shows the benefits on human decision-making performance in office workers, which translates to increased productivity. However, adoption of enhanced ventilation strategies is lagging. We sought to evaluate two of the perceived potential barriers to more widespread adoption-Economic and environmental costs. We estimated the energy consumption and associated per building occupant costs for office buildings in seven U.S. cities, representing different climate zones for three ventilation scenarios (standard practice (20 cfm/person), 30% enhanced ventilation, and 40 cfm/person) and four different heating, ventilation and air conditioning (HVAC) system strategies (Variable Air Volume (VAV) with reheat and a Fan Coil Unit (FCU), both with and without an energy recovery ventilator). We also estimated emissions of greenhouse gases associated with this increased energy usage, and, for comparison, converted this to the equivalent number of vehicles using greenhouse gas equivalencies. Lastly, we paired results from our previous research on cognitive function and ventilation with labor statistics to estimate the economic benefit of increased productivity associated with increasing ventilation rates. Doubling the ventilation rate from the American Society of Heating, Refrigeration and Air-Conditioning Engineers minimum cost less than $40 per person per year in all climate zones investigated. Using an energy recovery ventilation system significantly reduced energy costs, and in some scenarios led to a net savings. At the highest ventilation rate, adding an ERV essentially neutralized the environmental impact of enhanced ventilation (0.03 additional cars on the road per building across all cities). The same change in ventilation improved the performance of workers by 8%, equivalent to a $6500 increase in employee productivity each year. Reduced absenteeism and improved health are also seen with enhanced ventilation. The health benefits associated with enhanced ventilation rates far exceed the per-person energy costs relative to salary costs. Environmental impacts can be mitigated at regional, building, and individual-level scales through the transition to renewable energy sources, adoption of energy efficient systems and ventilation strategies, and promotion of other sustainable policies.

  15. Economic, Environmental and Health Implications of Enhanced Ventilation in Office Buildings

    PubMed Central

    MacNaughton, Piers; Pegues, James; Satish, Usha; Santanam, Suresh; Spengler, John; Allen, Joseph

    2015-01-01

    Introduction: Current building ventilation standards are based on acceptable minimums. Three decades of research demonstrates the human health benefits of increased ventilation above these minimums. Recent research also shows the benefits on human decision-making performance in office workers, which translates to increased productivity. However, adoption of enhanced ventilation strategies is lagging. We sought to evaluate two of the perceived potential barriers to more widespread adoption—Economic and environmental costs. Methods: We estimated the energy consumption and associated per building occupant costs for office buildings in seven U.S. cities, representing different climate zones for three ventilation scenarios (standard practice (20 cfm/person), 30% enhanced ventilation, and 40 cfm/person) and four different heating, ventilation and air conditioning (HVAC) system strategies (Variable Air Volume (VAV) with reheat and a Fan Coil Unit (FCU), both with and without an energy recovery ventilator). We also estimated emissions of greenhouse gases associated with this increased energy usage, and, for comparison, converted this to the equivalent number of vehicles using greenhouse gas equivalencies. Lastly, we paired results from our previous research on cognitive function and ventilation with labor statistics to estimate the economic benefit of increased productivity associated with increasing ventilation rates. Results: Doubling the ventilation rate from the American Society of Heating, Refrigeration and Air-Conditioning Engineers minimum cost less than $40 per person per year in all climate zones investigated. Using an energy recovery ventilation system significantly reduced energy costs, and in some scenarios led to a net savings. At the highest ventilation rate, adding an ERV essentially neutralized the environmental impact of enhanced ventilation (0.03 additional cars on the road per building across all cities). The same change in ventilation improved the performance of workers by 8%, equivalent to a $6500 increase in employee productivity each year. Reduced absenteeism and improved health are also seen with enhanced ventilation. Conclusions: The health benefits associated with enhanced ventilation rates far exceed the per-person energy costs relative to salary costs. Environmental impacts can be mitigated at regional, building, and individual-level scales through the transition to renewable energy sources, adoption of energy efficient systems and ventilation strategies, and promotion of other sustainable policies. PMID:26593933

  16. Using domiciliary non-invasive ventilator data downloads to inform clinical decision-making to optimise ventilation delivery and patient compliance

    PubMed Central

    Mansell, Stephanie K; Cutts, Steven; Hackney, Isobel; Wood, Martin J; Hawksworth, Kevin; Creer, Dean D; Kilbride, Cherry; Mandal, Swapna

    2018-01-01

    Introduction Ventilation parameter data from patients receiving home mechanical ventilation can be collected via secure data cards and modem technology. This can then be reviewed by clinicians and ventilator prescriptions adjusted. Typically available measures include tidal volume (VT), leak, respiratory rate, minute ventilation, patient triggered breaths, achieved pressures and patient compliance. This study aimed to assess the potential impact of ventilator data downloads on management of patients requiring home non-invasive ventilation (NIV). Methods A longitudinal within-group design with repeated measurements was used. Baseline ventilator data were downloaded, reviewed and adjustments made to optimise ventilation. Leak, VT and compliance data were collected for comparison at the first review and 3–7 weeks later. Ventilator data were monitored and amended remotely via a modem by a consultant physiotherapist between the first review and second appointment. Results Analysis of data from 52 patients showed increased patient compliance (% days used >4 hours) from 90% to 96% (p=0.007), increased usage from 6.53 to 6.94 hours (p=0.211) and a change in VT(9.4 vs 8.7 mL/kg/ideal body weight, p=0.022). There was no change in leak following review of NIV prescriptions (mean (SD): 43 (23.4) L/min vs 45 (19.9)L/min, p=0.272). Conclusion Ventilator data downloads, via early remote assessment, can help optimise patient ventilation through identification of modifiable factors, in particular interface leak and ventilator prescriptions. However, a prospective study is required to assess whether using ventilator data downloads provides value in terms of patient outcomes and cost-effectiveness. The presented data will help to inform the design of such a study. PMID:29531743

  17. A bench study of intensive-care-unit ventilators: new versus old and turbine-based versus compressed gas-based ventilators

    PubMed Central

    Thille, Arnaud W.; Lyazidi, Aissam; Richard, Jean-Christophe M.; Galia, Fabrice; Brochard, Laurent

    2009-01-01

    Objective To compare 13 commercially available, new-generation, intensive-care-unit (ICU) ventilators regarding trigger function, pressurization capacity during pressure-support ventilation (PSV), accuracy of pressure measurements and expiratory resistance. Design and Setting Bench study at a research laboratory in a university hospital. Material Four turbine-based ventilators and nine conventional servo-valve compressed-gas ventilators were tested using a two-compartment lung model. Results Three levels of effort were simulated. Each ventilator was evaluated at four PSV levels (5, 10, 15, and 20 cm H2O), with and without positive end-expiratory pressure (5 cm H2O, Trigger function was assessed as the time from effort onset to detectable pressurization. Pressurization capacity was evaluated using the airway pressure-time product computed as the net area under the pressure-time curve over the first 0.3 s after inspiratory effort onset. Expiratory resistance was evaluated by measuring trapped volume in controlled ventilation. Significant differences were found across the ventilators, with a range of triggering-delay from 42 ms to 88 ms for all conditions averaged (P<.001). Under difficult conditions, the triggering delay was longer than 100 ms and the pressurization was poor with five ventilators at PSV5 and three at PSV10, suggesting an inability to unload patient’s effort. On average, turbine-based ventilators performed better than conventional ventilators, which showed no improvement compared to a 2000 bench comparison. Conclusion Technical performances of trigger function, pressurization capacity and expiratory resistance vary considerably across new-generation ICU ventilators. ICU ventilators seem to have reached a technical ceiling in recent years, and some ventilators still perform inadequately. PMID:19352622

  18. Model-based setting of inspiratory pressure and respiratory rate in pressure-controlled ventilation.

    PubMed

    Schranz, C; Becher, T; Schädler, D; Weiler, N; Möller, K

    2014-03-01

    Mechanical ventilation carries the risk of ventilator-induced-lung-injury (VILI). To minimize the risk of VILI, ventilator settings should be adapted to the individual patient properties. Mathematical models of respiratory mechanics are able to capture the individual physiological condition and can be used to derive personalized ventilator settings. This paper presents model-based calculations of inspiration pressure (pI), inspiration and expiration time (tI, tE) in pressure-controlled ventilation (PCV) and a retrospective evaluation of its results in a group of mechanically ventilated patients. Incorporating the identified first order model of respiratory mechanics in the basic equation of alveolar ventilation yielded a nonlinear relation between ventilation parameters during PCV. Given this patient-specific relation, optimized settings in terms of minimal pI and adequate tE can be obtained. We then retrospectively analyzed data from 16 ICU patients with mixed pathologies, whose ventilation had been previously optimized by ICU physicians with the goal of minimization of inspiration pressure, and compared the algorithm's 'optimized' settings to the settings that had been chosen by the physicians. The presented algorithm visualizes the patient-specific relations between inspiration pressure and inspiration time. The algorithm's calculated results highly correlate to the physician's ventilation settings with r = 0.975 for the inspiration pressure, and r = 0.902 for the inspiration time. The nonlinear patient-specific relations of ventilation parameters become transparent and support the determination of individualized ventilator settings according to therapeutic goals. Thus, the algorithm is feasible for a variety of ventilated ICU patients and has the potential of improving lung-protective ventilation by minimizing inspiratory pressures and by helping to avoid the build-up of clinically significant intrinsic positive end-expiratory pressure.

  19. Academic Emergency Medicine Physicians' Knowledge of Mechanical Ventilation.

    PubMed

    Wilcox, Susan R; Strout, Tania D; Schneider, Jeffrey I; Mitchell, Patricia M; Smith, Jessica; Lutfy-Clayton, Lucienne; Marcolini, Evie G; Aydin, Ani; Seigel, Todd A; Richards, Jeremy B

    2016-05-01

    Although emergency physicians frequently intubate patients, management of mechanical ventilation has not been emphasized in emergency medicine (EM) education or clinical practice. The objective of this study was to quantify EM attendings' education, experience, and knowledge regarding mechanical ventilation in the emergency department. We developed a survey of academic EM attendings' educational experiences with ventilators and a knowledge assessment tool with nine clinical questions. EM attendings at key teaching hospitals for seven EM residency training programs in the northeastern United States were invited to participate in this survey study. We performed correlation and regression analyses to evaluate the relationship between attendings' scores on the assessment instrument and their training, education, and comfort with ventilation. Of 394 EM attendings surveyed, 211 responded (53.6%). Of respondents, 74.5% reported receiving three or fewer hours of ventilation-related education from EM sources over the past year and 98 (46%) reported receiving between 0-1 hour of education. The overall correct response rate for the assessment tool was 73.4%, with a standard deviation of 19.9. The factors associated with a higher score were completion of an EM residency, prior emphasis on mechanical ventilation during one's own residency, working in a setting where an emergency physician bears primary responsibility for ventilator management, and level of comfort with managing ventilated patients. Physicians' comfort was associated with the frequency of ventilator changes and EM management of ventilation, as well as hours of education. EM attendings report caring for mechanically ventilated patients frequently, but most receive fewer than three educational hours a year on mechanical ventilation, and nearly half receive 0-1 hour. Physicians' performance on an assessment tool for mechanical ventilation is most strongly correlated with their self-reported comfort with mechanical ventilation.

  20. Effects of types of ventilation system on indoor particle concentrations in residential buildings.

    PubMed

    Park, J S; Jee, N-Y; Jeong, J-W

    2014-12-01

    The objective of this study was to quantify the influence of ventilation systems on indoor particle concentrations in residential buildings. Fifteen occupied, single-family apartments were selected from three sites. The three sites have three different ventilation systems: unbalanced mechanical ventilation, balanced mechanical ventilation, and natural ventilation. Field measurements were conducted between April and June 2012, when outdoor air temperatures were comfortable. Number concentrations of particles, PM2.5 and CO2 , were continuously measured both outdoors and indoors. In the apartments with natural ventilation, I/O ratios of particle number concentrations ranged from 0.56 to 0.72 for submicron particles, and from 0.25 to 0.60 for particles larger than 1.0 μm. The daily average indoor particle concentration decreased to 50% below the outdoor level for submicron particles and 25% below the outdoor level for fine particles, when the apartments were mechanically ventilated. The two mechanical ventilation systems reduced the I/O ratios by 26% for submicron particles and 65% for fine particles compared with the natural ventilation. These results showed that mechanical ventilation can reduce exposure to outdoor particles in residential buildings. Results of this study confirm that mechanical ventilation with filtration can significantly reduce indoor particle levels compared with natural ventilation. The I/O ratios of particles substantially varied at the naturally ventilated apartments because of the influence of variable window opening conditions and unsteadiness of wind flow on the penetration of outdoor air particles. For better prediction of the exposure to outdoor particles in naturally ventilated residential buildings, it is important to understand the penetration of outdoor particles with variable window opening conditions. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. FiO2 delivered by a turbine portable ventilator with an oxygen concentrator in an Austere environment.

    PubMed

    Bordes, Julien; Erwan d'Aranda; Savoie, Pierre-Henry; Montcriol, Ambroise; Goutorbe, Philippe; Kaiser, Eric

    2014-09-01

    Management of critically ill patients in austere environments is a logistic challenge. Availability of oxygen cylinders for the mechanically ventilated patient may be difficult in such a context. A solution is to use a ventilator able to function with an oxygen concentrator. We tested the SeQual Integra™ (SeQual, San Diego, CA) 10-OM oxygen concentrator paired with the Pulmonetic System(®) LTV 1000 ventilator (Pulmonetic Systems, Minneapolis, MN) and evaluated the delivered fraction of inspired oxygen (FiO2) across a range of minute volumes and combinations of ventilator settings. Two LTV 1000 ventilators were tested. The ventilators were attached to a test lung and FiO2 was measured by a gas analyzer. Continuous-flow oxygen was generated by the OC from 0.5 L/min to 10 L/min and injected into the oxygen inlet port of the LTV 1000. Several combinations of ventilator settings were evaluated to determine the factors affecting the delivered FiO2. The LTV 1000 ventilator is a turbine ventilator that is able to deliver high FiO2 when functioning with an oxygen concentrator. However, modifications of the ventilator settings such as increase in minute ventilation affect delivered FiO2 even if oxygen flow is constant on the oxygen concentrator. The ability of an oxygen concentrator to deliver high FiO2 when used with a turbine ventilator makes this method of oxygen delivery a viable alternative to cylinders in austere environments when used with a turbine ventilator. However, FiO2 has to be monitored continuously because delivered FiO2 decreases when minute ventilation is increased. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. A bench study of intensive-care-unit ventilators: new versus old and turbine-based versus compressed gas-based ventilators.

    PubMed

    Thille, Arnaud W; Lyazidi, Aissam; Richard, Jean-Christophe M; Galia, Fabrice; Brochard, Laurent

    2009-08-01

    To compare 13 commercially available, new-generation, intensive-care-unit (ICU) ventilators in terms of trigger function, pressurization capacity during pressure-support ventilation (PSV), accuracy of pressure measurements, and expiratory resistance. Bench study at a research laboratory in a university hospital. Four turbine-based ventilators and nine conventional servo-valve compressed-gas ventilators were tested using a two-compartment lung model. Three levels of effort were simulated. Each ventilator was evaluated at four PSV levels (5, 10, 15, and 20 cm H2O), with and without positive end-expiratory pressure (5 cm H2O). Trigger function was assessed as the time from effort onset to detectable pressurization. Pressurization capacity was evaluated using the airway pressure-time product computed as the net area under the pressure-time curve over the first 0.3 s after inspiratory effort onset. Expiratory resistance was evaluated by measuring trapped volume in controlled ventilation. Significant differences were found across the ventilators, with a range of triggering delays from 42 to 88 ms for all conditions averaged (P < 0.001). Under difficult conditions, the triggering delay was longer than 100 ms and the pressurization was poor for five ventilators at PSV5 and three at PSV10, suggesting an inability to unload patient's effort. On average, turbine-based ventilators performed better than conventional ventilators, which showed no improvement compared to a bench comparison in 2000. Technical performance of trigger function, pressurization capacity, and expiratory resistance differs considerably across new-generation ICU ventilators. ICU ventilators seem to have reached a technical ceiling in recent years, and some ventilators still perform inadequately.

  3. The comfort of breathing: a study with volunteers assessing the influence of various modes of assisted ventilation.

    PubMed

    Russell, W C; Greer, J R

    2000-11-01

    To assess the subjective feeling of comfort of healthy volunteers breathing on various modes of ventilation used in intensive care. A randomized, prospective, double-blinded, crossover trial using volunteers. An intensive care unit (ICU) in a teaching hospital. We compared, by using healthy volunteers, the subjective feeling of comfort of three modes of ventilation used during the weaning phase of critical illness. We used healthy volunteers to avoid other distracting influences of intensive care that may confound the primary feeling of comfort. The modes we compared were synchronized intermittent mandatory ventilation, assisted spontaneous breathing, and biphasic positive airway pressure. The imposed ventilation was comparable with 50% of the volunteers' normal respiratory effort. The volunteers breathed via a mouthpiece through a ventilator circuit, and the modes of ventilation were introduced in a randomized manner. We measured visual analog scores for comfort for the three modes of ventilation and collected a ranking order and open-ended comments. We demonstrated that at the level of support we imposed, assisted spontaneous breathing was the most comfortable mode of ventilation and that synchronized intermittent mandatory ventilation was the most uncomfortable. These results were strongly supported by both the ranking scale and comments of the volunteers. Assisted spontaneous breathing was the most comfortable mode of ventilation because the pattern was primarily determined by the volunteer. Synchronized intermittent mandatory ventilation was the most uncomfortable because the ventilatory pattern was imposed on the volunteers, leading to ventilator-volunteer dyssynchrony. We also conclude there is wide individual variation in the subjective feeling of comfort. Whereas the mode of ventilation in ICUs is based primarily on the physiologic needs of the patient, the feeling of comfort may be considered when choosing an appropriate mode of ventilation during the weaning phase of critical illness.

  4. Dismantling the nuclear research reactor Thetis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Michiels, P.

    The research reactor Thetis, in service since 1967 and stopped in 2003, is part of the laboratories of the institution of nuclear science of the University of Ghent. The reactor, of the pool-type, was used as a neutron-source for the production of radio-isotopes and for activation analyses. The reactor is situated in a water pool with inner diameter of 3 m. and a depth of 7.5 m. The reactor core is situated 5.3 m under water level. Besides the reactor, the pool contains pneumatic loops, handling tools, graphite blocks for neutron moderation and other experimental equipment. The building houses storagemore » rooms for fissile material and sources, a pneumatic circuit for transportation of samples, primary and secondary cooling circuits, water cleaning resin circuits, a ventilation system and other necessary devices. Because of the experimental character of the reactor, laboratories with glove boxes and other tools were needed and are included in the dismantling program. The building is in 3 levels with a crawl-space. The ground-floor contains the ventilation installation, the purification circuits with tanks, cooling circuits and pneumatic transport system. On the first floor, around the reactor hall, the control-room, visiting area, end-station for pneumatic transport, waste-storage room, fuel storage room and the labs are located. The second floor contains a few laboratories and end stations of the two high speed transfer tubes. The lowest level of the pool is situated under ground level. The reactor has been operated at a power of 150 kW and had a max operating power of 250 kW. Belgoprocess has been selected to decommission the reactor, the labs, storage halls and associated circuits to free release the building for conventional reuse and for the removal of all its internals as legal defined. Besides the dose-rate risk and contamination risk, there is also an asbestos risk of contamination. During construction of the installation, asbestos-containing materials were used, which must be removed in controlled conditions. The ventilation system is considered free from nuclear contamination but it contains asbestos. This paper covers the organization of the dismantling work, the technical execution aspect and conclusions already known (dismantling is ongoing as this is written). (authors)« less

  5. Oxidative lung injury correlates with one-lung ventilation time during pulmonary lobectomy: a study of exhaled breath condensate and blood.

    PubMed

    García-de-la-Asunción, José; García-del-Olmo, Eva; Perez-Griera, Jaume; Martí, Francisco; Galan, Genaro; Morcillo, Alfonso; Wins, Richard; Guijarro, Ricardo; Arnau, Antonio; Sarriá, Benjamín; García-Raimundo, Miguel; Belda, Javier

    2015-09-01

    During lung lobectomy, the operated lung is collapsed and hypoperfused; oxygen deprivation is accompanied by reactive hypoxic pulmonary vasoconstriction. After lung lobectomy, ischaemia present in the collapsed state is followed by expansion-reperfusion and lung injury attributed to the production of reactive oxygen species. The primary objective of this study was to investigate the time course of several markers of oxidative stress simultaneously in exhaled breath condensate and blood and to determine the relationship between oxidative stress and one-lung ventilation time in patients undergoing lung lobectomy. This single-centre, observational, prospective study included 28 patients with non-small-cell lung cancer who underwent lung lobectomy. We measured the levels of hydrogen peroxide, 8-iso-PGF2α, nitrites plus nitrates and pH in exhaled breath condensate (n = 25). The levels of 8-iso-PGF2α and nitrites plus nitrates were also measured in blood (n = 28). Blood samples and exhaled breath condensate samples were collected from all patients at five time points: preoperatively; during one-lung ventilation, immediately before resuming two-lung ventilation; immediately after resuming two-lung ventilation; 60 min after resuming two-lung ventilation and 180 min after resuming two-lung ventilation. Both exhaled breath condensate and blood exhibited significant and simultaneous increases in oxidative-stress markers immediately before two-lung ventilation was resumed. However, all these values underwent larger increases immediately after resuming two-lung ventilation. In both exhaled breath condensate and blood, marker levels significantly and directly correlated with the duration of one-lung ventilation immediately before resuming two-lung ventilation and immediately after resuming two-lung ventilation. Although pH significantly decreased in exhaled breath condensate immediately after resuming two-lung ventilation, these pH values were inversely correlated with the duration of one-lung ventilation. During lung lobectomy, the operated lung is collapsed and oxidative injury occurs, with the levels of markers of oxidative stress increasing simultaneously in exhaled breath condensate and blood during one-lung ventilation. These increases were larger after resuming two-lung ventilation. Increases immediately before resuming two-lung ventilation and immediately after resuming two-lung ventilation were directly correlated with the duration of one-lung ventilation. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  6. TH-E-BRF-02: 4D-CT Ventilation Image-Based IMRT Plans Are Dosimetrically Comparable to SPECT Ventilation Image-Based Plans

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kida, S; University of Tokyo Hospital, Bunkyo, Tokyo; Bal, M

    Purpose: An emerging lung ventilation imaging method based on 4D-CT can be used in radiotherapy to selectively avoid irradiating highly-functional lung regions, which may reduce pulmonary toxicity. Efforts to validate 4DCT ventilation imaging have been focused on comparison with other imaging modalities including SPECT and xenon CT. The purpose of this study was to compare 4D-CT ventilation image-based functional IMRT plans with SPECT ventilation image-based plans as reference. Methods: 4D-CT and SPECT ventilation scans were acquired for five thoracic cancer patients in an IRB-approved prospective clinical trial. The ventilation images were created by quantitative analysis of regional volume changes (amore » surrogate for ventilation) using deformable image registration of the 4D-CT images. A pair of 4D-CT ventilation and SPECT ventilation image-based IMRT plans was created for each patient. Regional ventilation information was incorporated into lung dose-volume objectives for IMRT optimization by assigning different weights on a voxel-by-voxel basis. The objectives and constraints of the other structures in the plan were kept identical. The differences in the dose-volume metrics have been evaluated and tested by a paired t-test. SPECT ventilation was used to calculate the lung functional dose-volume metrics (i.e., mean dose, V20 and effective dose) for both 4D-CT ventilation image-based and SPECT ventilation image-based plans. Results: Overall there were no statistically significant differences in any dose-volume metrics between the 4D-CT and SPECT ventilation imagebased plans. For example, the average functional mean lung dose of the 4D-CT plans was 26.1±9.15 (Gy), which was comparable to 25.2±8.60 (Gy) of the SPECT plans (p = 0.89). For other critical organs and PTV, nonsignificant differences were found as well. Conclusion: This study has demonstrated that 4D-CT ventilation image-based functional IMRT plans are dosimetrically comparable to SPECT ventilation image-based plans, providing evidence to use 4D-CT ventilation imaging for clinical applications. Supported in part by Free to Breathe Young Investigator Research Grant and NIH/NCI R01 CA 093626. The authors thank Philips Radiation Oncology Systems for the Pinnacle3 treatment planning systems.« less

  7. 46 CFR 154.1200 - Mechanical ventilation system: General.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Mechanical ventilation system: General. 154.1200 Section... Equipment Cargo Area: Mechanical Ventilation System § 154.1200 Mechanical ventilation system: General. (a... cargo handling equipment must have a fixed, exhaust-type mechanical ventilation system. (b) The...

  8. 46 CFR 153.312 - Ventilation system standards.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.312 Ventilation system standards. A cargo handling space ventilation... (approx. 32.8 ft) from openings into or ventilation intakes for, accommodation or service spaces. (b) A...

  9. 46 CFR 153.312 - Ventilation system standards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.312 Ventilation system standards. A cargo handling space ventilation... (approx. 32.8 ft) from openings into or ventilation intakes for, accommodation or service spaces. (b) A...

  10. 46 CFR 153.312 - Ventilation system standards.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.312 Ventilation system standards. A cargo handling space ventilation... (approx. 32.8 ft) from openings into or ventilation intakes for, accommodation or service spaces. (b) A...

  11. 46 CFR 153.312 - Ventilation system standards.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.312 Ventilation system standards. A cargo handling space ventilation... (approx. 32.8 ft) from openings into or ventilation intakes for, accommodation or service spaces. (b) A...

  12. 46 CFR 153.312 - Ventilation system standards.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.312 Ventilation system standards. A cargo handling space ventilation... (approx. 32.8 ft) from openings into or ventilation intakes for, accommodation or service spaces. (b) A...

  13. 30 CFR 75.333 - Ventilation controls.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Ventilation controls. 75.333 Section 75.333... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.333 Ventilation controls. (a) For... ventilation control devices constructed after November 15, 1992, shall be built and maintained— (1) Between...

  14. 30 CFR 75.333 - Ventilation controls.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Ventilation controls. 75.333 Section 75.333... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.333 Ventilation controls. (a) For... ventilation control devices constructed after November 15, 1992, shall be built and maintained— (1) Between...

  15. 33 CFR 183.620 - Natural ventilation system.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Natural ventilation system. 183... (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Ventilation § 183.620 Natural ventilation system. (a) Except for compartments open to the atmosphere, a natural ventilation system that meets the...

  16. 33 CFR 183.620 - Natural ventilation system.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Natural ventilation system. 183... (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Ventilation § 183.620 Natural ventilation system. (a) Except for compartments open to the atmosphere, a natural ventilation system that meets the...

  17. [Bellows or bag? Testing 10 ventilators and some medical history comments].

    PubMed

    Kötter, K P; Maleck, W H; Altmannsberger, S; Herchet, J; Petroianu, G A

    1998-01-01

    We compared a new bellows ventilator (Kendall Cardiovent) with two other bellows (Dräger Resutator 63, Tagg Breathsaver) and seven bag or ball ventilators (Aerodyne Hope, Ambu Mark 3, Ambu Silicon, Dräger Resutator 2000, Laerdal Resu, Mercury CPR, Weinmann Combibag). Tidal volumes were measured with two Laerdal Recording Resusci Annies, one lying on the floor, one in a bed. Twelve participants performed mask ventilation with all ten devices on both manikins for two minutes, trying to achieve tidal volumes of between 0.8 and 1.21 as recommended by the AHA. The last ten ventilations each on the graphic strips were analysed for volume. The participants scored handling of the devices on a 6-point scale (1 = very good, 6 = insufficient). The results of the Cardiovent were compared to those of the other devices by rank sum test (percentage of correct ventilations) and sign test (subjective handling). The Cardiovent provided exact ventilation with 95% of ventilations) on the floor and 78% of ventilations in bed in the recommended range. However, the percentage of correct ventilations with the Cardiovent was not significantly different to the other devices except for a lower percentage of correct ventilations with the Combibag in the in bed setting. Concerning subjective handling, the Cardiovent was significantly superior to several ball ventilators.

  18. Lung volumes during sustained microgravity on Spacelab SLS-1

    NASA Technical Reports Server (NTRS)

    Elliott, Ann R.; Prisk, Gordon Kim; Guy, Harold J. B.; West, John B.

    1994-01-01

    Gravity is known to influence the topographical gradients of pulmonary ventilation, perfusion, and pleural pressures. The effect of sustained microgravity on lung volumes has not previously been investigated. Pulmonary function tests were performed by four subjects before, during, and after 9 days of microgravity exposure. Ground measurements were made in standing and supine postures. Tests were performed using a bag-in-box and flowmeter system and a respiratory mass spectrometer. Measurements of tidal volume (V(sub T)), expiratory reserve volume (ERV), inspiratory and expiratory vital capacities (IVC, EVC), functional residual capacity (FRC), and residual volume (RV) were made. During microgravity, V(sub T) decreased by 15%. IVC and EVC were slightly reduced during the first 24 hrs of microgravity and returned to 1 g standing values within 72 hrs after the onset of microgravity. FRC was reduced by 15% and ERV decreased by 10-20%. RV was significantly reduced by 18%. The reductions in FRC, ERV, and V(sub T) during microgravity are probably due to the cranial shift of the diaphragm and an increase in intrathoracic blood volume.

  19. Temperature of gas delivered from ventilators.

    PubMed

    Chikata, Yusuke; Onodera, Mutsuo; Imanaka, Hideaki; Nishimura, Masaji

    2013-01-01

    Although heated humidifiers (HHs) are the most efficient humidifying device for mechanical ventilation, some HHs do not provide sufficient humidification when the inlet temperature to the water chamber is high. Because portable and home-care ventilators use turbines, blowers, pistons, or compressors to inhale in ambient air, they may have higher gas temperature than ventilators with piping systems. We carried out a bench study to investigate the temperature of gas delivered from portable and home-care ventilators, including the effects of distance from ventilator outlet, fraction of inspiratory oxygen (FIO2), and minute volume (MV). We evaluated five ventilators equipped with turbine, blower, piston, or compressor system. Ambient air temperature was adjusted to 24°C ± 0.5°C, and ventilation was set at FIO2 0.21, 0.6, and 1.0, at MV 5 and 10 L/min. We analyzed gas temperature at 0, 40, 80, and 120 cm from ventilator outlet and altered ventilator settings. While temperature varied according to ventilators, the outlet gas temperature of ventilators became stable after, at the most, 5 h. Gas temperature was 34.3°C ± 3.9°C at the ventilator outlet, 29.5°C ± 2.2°C after 40 cm, 25.4°C ± 1.2°C after 80 cm and 25.1°C ± 1.2°C after 120 cm (P < 0.01). FIO2 and MV did not affect gas temperature. Gas delivered from portable and home-care ventilator was not too hot to induce heated humidifier malfunctioning. Gas soon declined when passing through the limb.

  20. A Chemical-Biological-Radio-Nuclear (CBRN) Filter can be Added to the Air-Outflow Port of a Ventilator to Protect a Home Ventilated Patient From Inhalation of Toxic Industrial Compounds.

    PubMed

    Be'eri, Eliezer; Owen, Simon; Beeri, Maurit; Millis, Scott R; Eisenkraft, Arik

    2018-02-21

    Chemical-biological-radio-nuclear (CBRN) gas masks are the standard means for protecting the general population from inhalation of toxic industrial compounds (TICs), for example after industrial accidents or terrorist attacks. However, such gas masks would not protect patients on home mechanical ventilation, as ventilator airflow would bypass the CBRN filter. We therefore evaluated in vivo the safety of adding a standard-issue CBRN filter to the air-outflow port of a home ventilator, as a method for providing TIC protection to such patients. Eight adult patients were included in the study. All had been on stable, chronic ventilation via a tracheostomy for at least 3 months before the study. Each patient was ventilated for a period of 1 hour with a standard-issue CBRN filter canister attached to the air-outflow port of their ventilator. Physiological and airflow measurements were made before, during, and after using the filter, and the patients reported their subjective sensation of ventilation continuously during the trial. For all patients, and throughout the entire study, no deterioration in any of the measured physiological parameters and no changes in measured airflow parameters were detected. All patients felt no subjective difference in the sensation of ventilation with the CBRN filter canister in situ, as compared with ventilation without it. This was true even for those patients who were breathing spontaneously and thus activating the ventilator's trigger/sensitivity function. No technical malfunctions of the ventilators occurred after addition of the CBRN filter canister to the air-outflow ports of the ventilators. A CBRN filter canister can be added to the air-outflow port of chronically ventilated patients, without causing an objective or subjective deterioration in the quality of the patients' mechanical ventilation. (Disaster Med Public Health Preparedness. 2018;page 1 of 5).

  1. Closed loop ventilation mode in Intensive Care Unit: a randomized controlled clinical trial comparing the numbers of manual ventilator setting changes.

    PubMed

    Arnal, Jean-Michel; Garnero, Aude; Novotni, Dominik; Corno, Gaëlle; Donati, Stéphane-Yannis; Demory, Didier; Quintana, Gabrielle; Ducros, Laurent; Laubscher, Thomas; Durand-Gasselin, Jacques

    2018-01-01

    There is an equipoise regarding closed-loop ventilation modes and the ability to reduce workload for providers. On one hand some settings are managed by the ventilator but on another hand the automatic mode introduces new settings for the user. This randomized controlled trial compared the number of manual ventilator setting changes between a full closed loop ventilation and oxygenation mode (INTELLiVENT-ASV®) and conventional ventilation modes (volume assist control and pressure support) in Intensive Care Unit (ICU) patients. The secondary endpoints were to compare the number of arterial blood gas analysis, the sedation dose and the user acceptance. Sixty subjects with an expected duration of mechanical ventilation of at least 48 hours were randomized to be ventilated using INTELLiVENT-ASV® or conventional modes with a protocolized weaning. All manual ventilator setting changes were recorded continuously from inclusion to successful extubation or death. Arterial blood gases were performed upon decision of the clinician in charge. User acceptance score was assessed for nurses and physicians once daily using a Likert Scale. The number of manual ventilator setting changes per 24 h-period per subject was lower in INTELLiVENT-ASV® as compared to conventional ventilation group (5 [4-7] versus 10 [7-17]) manuals settings per subject per day [P<0.001]). The number of arterial blood gas analysis and the sedation doses were not significantly different between the groups. Nurses and physicians reported that INTELLiVENT-ASV® was significantly easier to use as compared to conventional ventilation (P<0.001 for nurses and P<0.01 for physicians). For mechanically ventilated ICU patients, INTELLiVENT-ASV® significantly reduces the number of manual ventilator setting changes with the same number of arterial blood gas analysis and sedation dose, and is easier to use for the caregivers as compared to conventional ventilation modes.

  2. Variability in usual care mechanical ventilation for pediatric acute lung injury: the potential benefit of a lung protective computer protocol.

    PubMed

    Khemani, Robinder G; Sward, Katherine; Morris, Alan; Dean, J Michael; Newth, Christopher J L

    2011-11-01

    Although pediatric intensivists claim to embrace lung protective ventilation for acute lung injury (ALI), ventilator management is variable. We describe ventilator changes clinicians made for children with hypoxemic respiratory failure, and evaluate the potential acceptability of a pediatric ventilation protocol. This was a retrospective cohort study performed in a tertiary care pediatric intensive care unit (PICU). The study period was from January 2000 to July 2007. We included mechanically ventilated children with PaO(2)/FiO(2) (P/F) ratio less than 300. We assessed variability in ventilator management by evaluating actual changes to ventilator settings after an arterial blood gas (ABG). We evaluated the potential acceptability of a pediatric mechanical ventilation protocol we adapted from National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI) Acute Respiratory Distress Syndrome (ARDS) Network protocols by comparing actual practice changes in ventilator settings to changes that would have been recommended by the protocol. A total of 2,719 ABGs from 402 patients were associated with 6,017 ventilator settings. Clinicians infrequently decreased FiO(2), even when the PaO(2) was high (>68 mmHg). The protocol would have recommended more positive end expiratory pressure (PEEP) than was used in actual practice 42% of the time in the mid PaO(2) range (55-68 mmHg) and 67% of the time in the low PaO(2) range (<55 mmHg). Clinicians often made no change to either peak inspiratory pressure (PIP) or ventilator rate (VR) when the protocol would have recommended a change, even when the pH was greater than 7.45 with PIP at least 35 cmH(2)O. There may be lost opportunities to minimize potentially injurious ventilator settings for children with ALI. A reproducible pediatric mechanical ventilation protocol could prompt clinicians to make ventilator changes that are consistent with lung protective ventilation.

  3. 46 CFR 154.1205 - Mechanical ventilation system: Standards.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Mechanical ventilation system: Standards. 154.1205... Equipment Cargo Area: Mechanical Ventilation System § 154.1205 Mechanical ventilation system: Standards. (a) Each exhaust type mechanical ventilation system required under § 154.1200 (a) must have ducts for...

  4. 21 CFR 868.5975 - Ventilator tubing.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ventilator tubing. 868.5975 Section 868.5975 Food... DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5975 Ventilator tubing. (a) Identification. Ventilator tubing is a device intended for use as a conduit for gases between a ventilator and a patient...

  5. Ventilation and ventilators.

    PubMed

    Hayes, B

    1982-01-01

    The history of ventilation is reviewed briefly and recent developments in techniques of ventilation are discussed. Operating features of ventilators have changed in the past few years, partly as the result of clinical progress; yet, technology appears to have outstripped the clinician's ability to harness it most effectively. Clinical discipline and training of medical staff in the use of ventilators could be improved. The future is promising if clinician and designer can work together closely. Ergonomics of ventilators and their controls and the provision of alarms need special attention. Microprocessors are likely to feature prominently in the next generation of designs.

  6. Elective ventilation for organ donation: law, policy and public ethics.

    PubMed

    Coggon, John

    2013-03-01

    This paper examines questions concerning elective ventilation, contextualised within English law and policy. It presents the general debate with reference both to the Exeter Protocol on elective ventilation, and the considerable developments in legal principle since the time that that protocol was declared to be unlawful. I distinguish different aspects of what might be labelled elective ventilation policies under the following four headings: 'basic elective ventilation'; 'epistemically complex elective ventilation'; 'practically complex elective ventilation'; and 'epistemically and practically complex elective ventilation'. I give a legal analysis of each. In concluding remarks on their potential practical viability, I emphasise the importance not just of ascertaining the legal and ethical acceptability of these and other forms of elective ventilation, but also of assessing their professional and political acceptability. This importance relates both to the successful implementation of the individual practices, and to guarding against possible harmful effects in the wider efforts to increase the rates of posthumous organ donation.

  7. Adaptive support ventilation: State of the art review

    PubMed Central

    Fernández, Jaime; Miguelena, Dayra; Mulett, Hernando; Godoy, Javier; Martinón-Torres, Federico

    2013-01-01

    Mechanical ventilation is one of the most commonly applied interventions in intensive care units. Despite its life-saving role, it can be a risky procedure for the patient if not applied appropriately. To decrease risks, new ventilator modes continue to be developed in an attempt to improve patient outcomes. Advances in ventilator modes include closed-loop systems that facilitate ventilator manipulation of variables based on measured respiratory parameters. Adaptive support ventilation (ASV) is a positive pressure mode of mechanical ventilation that is closed-loop controlled, and automatically adjust based on the patient's requirements. In order to deliver safe and appropriate patient care, clinicians need to achieve a thorough understanding of this mode, including its effects on underlying respiratory mechanics. This article will discuss ASV while emphasizing appropriate ventilator settings, their advantages and disadvantages, their particular effects on oxygenation and ventilation, and the monitoring priorities for clinicians. PMID:23833471

  8. [The incidence and risk factors of ventilator-associated pneumonia in patients with severe traumatic brain injury].

    PubMed

    Marjanović, Vesna; Novak, Vesna; Velicković, Ljubinka; Marjanović, Goran

    2011-01-01

    Patients with severe traumatic brain injury are at a risk of developing ventilator-associated pneumonia. The aim of this study was to describe the incidence, etiology, risk factors for development of ventilator-associated pneumonia and outcome in patients with severe traumatic brain injury. A retrospective study was done in 72 patients with severe traumatic brain injury, who required mechanical ventilation for more than 48 hours. Ventilator-associated pneumonia was found in 31 of 72 (43.06%) patients with severe traumatic brain injury. The risk factors for ventilator-associated pneumonia were: prolonged mechanical ventilation (12.42 vs 4.34 days, p < 0.001), longer stay at intensive care unit (17 vs 5 days, p < 0.001) and chest injury (51.61 vs 19.51%, p < 0.009) compared to patients without ventilator-associated pneumonia. The mortality rate in the patients with ventilator-associated pneumonia was higher (38.71 vs 21.95%, p = 0.12). The development of ventilator-associated pneumonia in patients with severe traumatic brain injury led to the increased morbidity due to the prolonged mechanical ventilation, longer stay at intensive care unit and chest injury, but had no effect on mortality.

  9. A polyurethane cuffed endotracheal tube is associated with decreased rates of ventilator-associated pneumonia.

    PubMed

    Miller, Melissa A; Arndt, Jennifer L; Konkle, Mark A; Chenoweth, Carol E; Iwashyna, Theodore J; Flaherty, Kevin R; Hyzy, Robert C

    2011-06-01

    The aim of this study was to determine whether the use of a polyurethane-cuffed endotracheal tube would result in a decrease in ventilator-associated pneumonia rate. We replaced conventional endotracheal tube with a polyurethane-cuff endotracheal tube (Microcuff, Kimberly-Clark Corporation, Rosewell, Ga) in all adult mechanically ventilated patients throughout our large academic hospital from July 2007 to June 2008. We retrospectively compared the rates of ventilator-associated pneumonia before, during, and after the intervention year by interrupted time-series analysis. Ventilator-associated pneumonia rates decreased from 5.3 per 1000 ventilator days before the use of the polyurethane-cuffed endotracheal tube to 2.8 per 1000 ventilator days during the intervention year (P = .0138). During the first 3 months after return to conventional tubes, the rate of ventilator-associated pneumonia was 3.5/1000 ventilator days. Use of the polyurethane-cuffed endotracheal tube was associated with an incidence risk ratio of ventilator-associated pneumonia of 0.572 (95% confidence interval, 0.340-0.963). In statistical regression analysis controlling for other possible alterations in the hospital environment, as measured by rate of tracheostomy-ventilator-associated pneumonia, the incidence risk ratio of ventilator-associated pneumonia in patients intubated with polyurethane-cuffed endotracheal tube was 0.565 (P = .032; 95% confidence interval, 0.335-0.953). Use of a polyurethane-cuffed endotracheal tube was associated with a significant decrease in the rate of ventilator-associated pneumonia in our study. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Prone versus supine position in mechanically ventilated children: a pilot study.

    PubMed

    Sawhney, Ashu; Kumar, Nirmal; Sreenivas, Vishnubhatla; Gupta, Sangeeta; Tyagi, Vineet; Puliyel, Jacob M

    2005-05-01

    It is known that mechanically ventilated patients in the prone position have improved oxygenation compared with those supine. We did a prospective, randomized, controlled trial to evaluate the effect of prone position during mechanical ventilation, on survival in critically ill children. Forty-two children needing mechanical ventilation for various illnesses were randomized to receive initial ventilation for four hours prone or supine by drawing lots. Initial severity of illness and blood gases in all children were noted. In a crossover design, after the initial four hours the children were turned over and ventilated in the alternate posture for an hour. Oxygenation parameters and mean airway pressures were noted at one hour, four hours, and five hours. Mortality, duration of ventilation, and the above parameters were compared in the two groups. Initial PRISM scores were similar in the two groups. Mortality in the prone group was less than in the supine group. The odds ratio of mortality was 0.20 (95% CI 0.05-0.75). Duration of ventilation was similar in the two groups. The oxygenation index was significantly lower in the prone group at one, four, and five hours after onset of ventilation. Prone position in the first few hours of ventilation significantly improves gas exchange and oxygenation, reduces the mean airway pressures required to ventilate children, and may cause significant improvement in survival. Our study protocol allowed ventilator settings to be changed as needed during ventilation.

  11. The effect of electromagnetic interference from mobile communication on the performance of intensive care ventilators.

    PubMed

    Jones, R P; Conway, D H

    2005-08-01

    Electromagnetic interference produced by wireless communication can affect medical devices and hospital policies exist to address this risk. During the transfer of ventilated patients, these policies may be compromised by essential communication between base and receiving hospitals. Local wireless networks (e.g. Bluetooth) may reduce the 'spaghetti syndrome' of wires and cables seen on intensive care units, but also generate electromagnetic interference. The aim of this study was to investigate these effects on displayed and actual ventilator performance. Five ventilators were tested: Drager Oxylog 2000, BREAS LTV-1000, Respironics BiPAP VISION, Puritan Bennett 7200 and 840. Electromagnetic interference was generated by three devices: Simoco 8020 radio handset, Nokia 7210 and Nokia 6230 mobile phone, Nokia 6230 communicating via Bluetooth with a Palm Tungsten T Personal Digital Assistant. We followed the American National Standard Recommended Practice for On-Site, Ad Hoc Testing (ANSI C63) for electromagnetic interference. We used a ventilator tester, to simulate healthy adult lungs and measure ventilator performance. The communication device under test was moved in towards each ventilator from a distance of 1 m in six axes. Alarms or error codes on the ventilator were recorded, as was ventilator performance. All ventilators tested, except for the Respironics VISION, showed a display error when subjected to electromagnetic interference from the Nokia phones and Simoco radio. Ventilator performance was only affected by the radio which caused the Puritan Bennett 840 to stop functioning completely. The transfer ventilators' performance were not affected by radio or mobile phone, although the mobile phone did trigger a low-power alarm. Effects on intensive care ventilators included display reset, with the ventilator restoring normal display function within 2 s, and low-power/low-pressure alarms. Bluetooth transmission had no effect on the function of all the ventilators tested. In a clinical setting, high-power-output devices such as a two-way radio may cause significant interference in ventilator function. Medium-power-output devices such as mobile phones may cause minor alarm triggers. Low-power-output devices such as Bluetooth appear to cause no interference with ventilator function.

  12. TU-G-BRA-04: Changes in Regional Lung Function Measured by 4D-CT Ventilation Imaging for Thoracic Radiotherapy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nakajima, Y; Kadoya, N; Kabus, S

    Purpose: To test the hypothesis: 4D-CT ventilation imaging can show the known effects of radiotherapy on lung function: (1) radiation-induced ventilation reductions, and (2) ventilation increases caused by tumor regression. Methods: Repeat 4D-CT scans (pre-, mid- and/or post-treatment) were acquired prospectively for 11 thoracic cancer patients in an IRB-approved clinical trial. A ventilation image for each time point was created using deformable image registration and the Hounsfield unit (HU)-based or Jacobian-based metric. The 11 patients were divided into two subgroups based on tumor volume reduction using a threshold of 5 cm{sup 3}. To quantify radiation-induced ventilation reduction, six patients whomore » showed a small tumor volume reduction (<5 cm{sup 3}) were analyzed for dose-response relationships. To investigate ventilation increase caused by tumor regression, two of the other five patients were analyzed to compare ventilation changes in the lung lobes affected and unaffected by the tumor. The remaining three patients were excluded because there were no unaffected lobes. Results: Dose-dependent reductions of HU-based ventilation were observed in a majority of the patient-specific dose-response curves and in the population-based dose-response curve, whereas no clear relationship was seen for Jacobian-based ventilation. The post-treatment population-based dose-response curve of HU-based ventilation demonstrated the average ventilation reductions of 20.9±7.0% at 35–40 Gy (equivalent dose in 2-Gy fractions, EQD2), and 40.6±22.9% at 75–80 Gy EQD2. Remarkable ventilation increases in the affected lobes were observed for the two patients who showed an average tumor volume reduction of 37.1 cm{sup 3} and re-opening airways. The mid-treatment increase in HU-based ventilation of patient 3 was 100.4% in the affected lobes, which was considerably greater than 7.8% in the unaffected lobes. Conclusion: This study has demonstrated that 4D-CT ventilation imaging shows the known effects of radiotherapy on lung function: radiation-induced ventilation reduction and ventilation increase caused by tumor regression, providing validation for 4D-CT ventilation imaging. This study was supported in part by a National Lung Cancer Partnership Young Investigator Research grant.« less

  13. Pilot Intervention Study of Household Ventilation and Fine Particulate Matter Concentrations in a Low-Income Urban Area, Dhaka, Bangladesh.

    PubMed

    Weaver, Anne M; Parveen, Shahana; Goswami, Doli; Crabtree-Ide, Christina; Rudra, Carole; Yu, Jihnhee; Mu, Lina; Fry, Alicia M; Sharmin, Iffat; Luby, Stephen P; Ram, Pavani K

    2017-08-01

    Fine particulate matter (PM 2.5 ) is a risk factor for pneumonia; ventilation may be protective. We tested behavioral and structural ventilation interventions on indoor PM 2.5 in Dhaka, Bangladesh. We recruited 59 good ventilation (window or door in ≥ 3 walls) and 29 poor ventilation (no window, one door) homes. We monitored baseline indoor and outdoor PM 2.5 for 48 hours. We asked all participants to increase ventilation behavior, including opening windows and doors, and operating fans. Where permitted, we installed windows in nine poor ventilation homes, then repeated PM 2.5 monitoring. We estimated effects using linear mixed-effects models and conducted qualitative interviews regarding motivators and barriers to ventilation. Compared with poor ventilation homes, good ventilation homes were larger, their residents wealthier and less likely to use biomass fuel. In multivariable linear mixed-effects models, ventilation structures and opening a door or window were inversely associated with the number of hours PM 2.5 concentrations exceeded 100 and 250 μg/m 3 . Outdoor air pollution was positively associated with the number of hours PM 2.5 concentrations exceeded 100 and 250 μg/m 3 . Few homes accepted window installation, due to landlord refusal and fear of theft. Motivators for ventilation behavior included cooling of the home and sunlight; barriers included rain, outdoor odors or noise, theft risk, mosquito entry, and, for fan use, perceptions of wasting electricity or unavailability of electricity. We concluded that ventilation may reduce indoor PM 2.5 concentrations but, there are barriers to increasing ventilation and, in areas with high ambient PM 2.5 concentrations, indoor concentrations may remain above recommended levels.

  14. Duration of Mechanical Ventilation in the Emergency Department.

    PubMed

    Angotti, Lauren B; Richards, Jeremy B; Fisher, Daniel F; Sankoff, Jeffrey D; Seigel, Todd A; Al Ashry, Haitham S; Wilcox, Susan R

    2017-08-01

    Due to hospital crowding, mechanically ventilated patients are increasingly spending hours boarding in emergency departments (ED) before intensive care unit (ICU) admission. This study aims to evaluate the association between time ventilated in the ED and in-hospital mortality, duration of mechanical ventilation, ICU and hospital length of stay (LOS). This was a multi-center, prospective, observational study of patients ventilated in the ED, conducted at three academic Level I Trauma Centers from July 2011 to March 2013. All consecutive adult patients on invasive mechanical ventilation were eligible for enrollment. We performed a Cox regression to assess for a mortality effect for mechanically ventilated patients with each hour of increasing LOS in the ED and multivariable regression analyses to assess for independently significant contributors to in-hospital mortality. Our primary outcome was in-hospital mortality, with secondary outcomes of ventilator days, ICU LOS and hospital LOS. We further commented on use of lung protective ventilation and frequency of ventilator changes made in this cohort. We enrolled 535 patients, of whom 525 met all inclusion criteria. Altered mental status without respiratory pathology was the most common reason for intubation, followed by trauma and respiratory failure. Using iterated Cox regression, a mortality effect occurred at ED time of mechanical ventilation > 7 hours, and the longer ED stay was also associated with a longer total duration of intubation. However, adjusted multivariable regression analysis demonstrated only older age and admission to the neurosciences ICU as independently associated with increased mortality. Of interest, only 23.8% of patients ventilated in the ED for over seven hours had changes made to their ventilator. In a prospective observational study of patients mechanically ventilated in the ED, there was a significant mortality benefit to expedited transfer of patients into an appropriate ICU setting.

  15. Protective ventilation of preterm lambs exposed to acute chorioamnionitis does not reduce ventilation-induced lung or brain injury.

    PubMed

    Barton, Samantha K; Moss, Timothy J M; Hooper, Stuart B; Crossley, Kelly J; Gill, Andrew W; Kluckow, Martin; Zahra, Valerie; Wong, Flora Y; Pichler, Gerhard; Galinsky, Robert; Miller, Suzanne L; Tolcos, Mary; Polglase, Graeme R

    2014-01-01

    The onset of mechanical ventilation is a critical time for the initiation of cerebral white matter (WM) injury in preterm neonates, particularly if they are inadvertently exposed to high tidal volumes (VT) in the delivery room. Protective ventilation strategies at birth reduce ventilation-induced lung and brain inflammation and injury, however its efficacy in a compromised newborn is not known. Chorioamnionitis is a common antecedent of preterm birth, and increases the risk and severity of WM injury. We investigated the effects of high VT ventilation, after chorioamnionitis, on preterm lung and WM inflammation and injury, and whether a protective ventilation strategy could mitigate the response. Pregnant ewes (n = 18) received intra-amniotic lipopolysaccharide (LPS) 2 days before delivery, instrumentation and ventilation at 127±1 days gestation. Lambs were either immediately euthanased and used as unventilated controls (LPSUVC; n = 6), or were ventilated using an injurious high VT strategy (LPSINJ; n = 5) or a protective ventilation strategy (LPSPROT; n = 7) for a total of 90 min. Mean arterial pressure, heart rate and cerebral haemodynamics and oxygenation were measured continuously. Lungs and brains underwent molecular and histological assessment of inflammation and injury. LPSINJ lambs had poorer oxygenation than LPSPROT lambs. Ventilation requirements and cardiopulmonary and systemic haemodynamics were not different between ventilation strategies. Compared to unventilated lambs, LPSINJ and LPSPROT lambs had increases in pro-inflammatory cytokine expression within the lungs and brain, and increased astrogliosis (p<0.02) and cell death (p<0.05) in the WM, which were equivalent in magnitude between groups. Ventilation after acute chorioamnionitis, irrespective of strategy used, increases haemodynamic instability and lung and cerebral inflammation and injury. Mechanical ventilation is a potential contributor to WM injury in infants exposed to chorioamnionitis.

  16. Limiting ventilator-induced lung injury through individual electronic medical record surveillance.

    PubMed

    Herasevich, Vitaly; Tsapenko, Mykola; Kojicic, Marija; Ahmed, Adil; Kashyap, Rachul; Venkata, Chakradhar; Shahjehan, Khurram; Thakur, Sweta J; Pickering, Brian W; Zhang, Jiajie; Hubmayr, Rolf D; Gajic, Ognjen

    2011-01-01

    To improve the safety of ventilator care and decrease the risk of ventilator-induced lung injury, we designed and tested an electronic algorithm that incorporates patient characteristics and ventilator settings, allowing near-real-time notification of bedside providers about potentially injurious ventilator settings. Electronic medical records of consecutive patients who received invasive ventilation were screened in three Mayo Clinic Rochester intensive care units. The computer system alerted bedside providers via the text paging notification about potentially injurious ventilator settings. Alert criteria included a Pao2/Fio2 ratio of <300 mm Hg, free text search for the words "edema" or "bilateral + infiltrates" on the chest radiograph report, a tidal volume of >8 mL/kg predicted body weight (based on patient gender and height), a plateau pressure of >30 cm H2O, and a peak airway pressure of >35 cm H2O. Respiratory therapists answered a brief online satisfaction survey. Ventilator-induced lung injury risk was compared before and after the introduction of ventilator-induced lung injury alert. The prevalence of acute lung injury was 42% (n = 490) among 1,159 patients receiving >24 hrs of invasive ventilation. The system sent 111 alerts for 80 patients, with a positive predictive value of 59%. The exposure to potentially injurious ventilation decreased after the intervention from 40.6 ± 74.6 hrs to 26.9 ± 77.3 hrs (p = .004). Electronic medical record surveillance of mechanically ventilated patients accurately detects potentially injurious ventilator settings and is able to influence bedside practice at moderate costs. Its implementation is associated with decreased patient exposure to potentially injurious mechanical ventilation settings.

  17. Winter ventilation rates at primary schools: comparison between Portugal and Finland.

    PubMed

    Canha, N; Almeida, S M; Freitas, M C; Täubel, M; Hänninen, O

    2013-01-01

    This study focused on examination of ventilation rates in classrooms with two different types of ventilation systems: natural and mechanical. Carbon dioxide (CO2) measurements were conducted in primary schools of Portugal characterized by natural ventilation and compared to Finland where mechanical ventilation is the norm. The winter period was selected since this season exerts a great influence in naturally ventilated classrooms, where opening of windows and doors occurs due to outdoor atmospheric conditions. The ventilation rates were calculated by monitoring CO2 concentrations generated by the occupants (used as a tracer gas) and application of the buildup phase method. A comparison between both countries' results was conducted with respect to ventilation rates and how these levels corresponded to national regulatory standards. Finnish primary schools (n = 2) registered a mean ventilation rate of 13.3 L/s per person, which is higher than the recommended ventilation standards. However, the Finnish classroom that presented the lowest ventilation rate (7.2 L/s per person) displayed short-term CO2 levels above 1200 ppm, which is the threshold limit value (TLV) recommended by national guidelines. The Portuguese classrooms (n = 2) showed low ventilation rates with mean values of 2.4 L/s per person, which is markedly lower than the minimum recommended value of 7 L/s per person as defined by ASHRAE and 20% less than the REHVA minimum of 3 L/s per person. Carbon dioxide levels of 1000 ppm, close to the TLV of 1200 ppm, were also reached in both Portuguese classrooms studied. The situation in Portugal indicates a potentially serious indoor air quality problem and strengthens the need for intervention to improve ventilation rates in naturally ventilated classrooms.

  18. Ventilation of the Subtropical North Atlantic: Locations and Times of Last Ventilation Estimated Using Tracer Constraints From GEOTRACES Section GA03

    NASA Astrophysics Data System (ADS)

    Holzer, Mark; Smethie, William M.; Ting, Yu-Heng

    2018-04-01

    The ventilation of the subtropical North Atlantic along GEOTRACES section GA03 is quantified in terms of where and how long ago water was last in the mixed layer. Measurements of T, S, PO4∗, CFC-11, CFC-12, SF6, and estimates of prebomb 14C are deconvolved for the boundary propagator G using a maximum-entropy approach. From G, we calculate the fractions of water last ventilated in specified surface regions Ωw. We estimate that (56 ± 13)% of the water deeper than 1,000 m was ventilated in northern high latitudes, (15 ± 5)% in the Mediterranean, and (27 ± 12)% in the Southern Ocean. Below the thermocline and outside the deep western boundary current, mean ages of Ωw-ventilated water exceed a century. Consequently, memory of where last ventilation occurred tends to get lost and the deep mean-age patterns of Ωw-ventilated water are broadly similar for all Ωw. The mean ventilation ages, averaged over the section with Ωw-fraction weights, are roughly 200 years for all deep water masses except for water last ventilated south of the Antarctic divergence, which is about twice as old. The uncertainties in the section-mean profiles of the Ωw fractions and their mean ages are ˜50% and ˜20%, respectively. The Ωw fractions have vertically diffuse overlapping patterns suggesting significant diapycnal mixing, consistent with century-scale mean ages. We quantify the seasonal cycle of ventilation and find that in both hemispheres peak ventilation occurs during late winter and early spring, but Northern Hemisphere ventilated deep waters have a more pronounced seasonal cycle with nearly zero summertime ventilation.

  19. AT1 receptor blocker losartan protects against mechanical ventilation-induced diaphragmatic dysfunction

    PubMed Central

    Kwon, Oh Sung; Smuder, Ashley J.; Wiggs, Michael P.; Hall, Stephanie E.; Sollanek, Kurt J.; Morton, Aaron B.; Talbert, Erin E.; Toklu, Hale Z.; Tumer, Nihal

    2015-01-01

    Mechanical ventilation is a life-saving intervention for patients in respiratory failure. Unfortunately, prolonged ventilator support results in diaphragmatic atrophy and contractile dysfunction leading to diaphragm weakness, which is predicted to contribute to problems in weaning patients from the ventilator. While it is established that ventilator-induced oxidative stress is required for the development of ventilator-induced diaphragm weakness, the signaling pathway(s) that trigger oxidant production remain unknown. However, recent evidence reveals that increased plasma levels of angiotensin II (ANG II) result in oxidative stress and atrophy in limb skeletal muscles. Using a well-established animal model of mechanical ventilation, we tested the hypothesis that increased circulating levels of ANG II are required for both ventilator-induced diaphragmatic oxidative stress and diaphragm weakness. Cause and effect was determined by administering an angiotensin-converting enzyme inhibitor (enalapril) to prevent ventilator-induced increases in plasma ANG II levels, and the ANG II type 1 receptor antagonist (losartan) was provided to prevent the activation of ANG II type 1 receptors. Enalapril prevented the increase in plasma ANG II levels but did not protect against ventilator-induced diaphragmatic oxidative stress or diaphragm weakness. In contrast, losartan attenuated both ventilator-induced oxidative stress and diaphragm weakness. These findings indicate that circulating ANG II is not essential for the development of ventilator-induced diaphragm weakness but that activation of ANG II type 1 receptors appears to be a requirement for ventilator-induced diaphragm weakness. Importantly, these experiments provide the first evidence that the Food and Drug Administration-approved drug losartan may have clinical benefits to protect against ventilator-induced diaphragm weakness in humans. PMID:26359481

  20. Lung-protective mechanical ventilation does not protect against acute kidney injury in patients without lung injury at onset of mechanical ventilation.

    PubMed

    Cortjens, Bart; Royakkers, Annick A N M; Determann, Rogier M; van Suijlen, Jeroen D E; Kamphuis, Stephan S; Foppen, Jannetje; de Boer, Anita; Wieland, Cathrien W; Spronk, Peter E; Schultz, Marcus J; Bouman, Catherine S C

    2012-06-01

    Preclinical and clinical studies suggest that mechanical ventilation contributes to the development of acute kidney injury (AKI), particularly in the setting of lung-injurious ventilator strategies. To determine whether ventilator settings in critically ill patients without acute lung injury (ALI) at onset of mechanical ventilation affect the development of AKI. Secondary analysis of a randomized controlled trial (N = 150), comparing conventional tidal volume (V(T), 10 mL/kg) with low tidal volume (V(T), 6 mL/kg) mechanical ventilation in critically ill patients without ALI at randomization. During the first 5 days of mechanical ventilation, the RIFLE class was determined daily, whereas neutrophil gelatinase-associated lipocalin and cystatin C levels were measured in plasma collected on days 0, 2, and 4. Eighty-six patients had no AKI at inclusion, and 18 patients (21%) subsequently developed AKI, but without significant difference between ventilation strategies. (Cumulative hazard, 0.26 vs 0.23; P = .88.) The courses of neutrophil gelatinase-associated lipocalin and cystatin C plasma levels did not differ significantly between randomization groups. In the present study in critically patients without ALI at onset of mechanical ventilation, lower tidal volume ventilation did not reduce the development or worsening of AKI compared with conventional tidal volume ventilation. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. Natural ventilation of buildings: opposing wind and buoyancy

    NASA Astrophysics Data System (ADS)

    Linden, Paul; Hunt, Gary

    1998-11-01

    The use of natural ventilation in buildings is an attractive way to reduce energy usage thereby reducing costs and CO2 emissions. Generally, it is necessary to remove excess heat from a building and the designer can use the buoyancy forces associated with the above ambient temperatures within the building to drive a flow - 'stack' ventilation. The most efficient mode is displacement ventilation where warm air accumulates near the top of the building and flows out through upper level vents and cooler air flows in at lower levels. Ventilation will also be driven between these lower and upper openings by the wind. We report on laboratory modeling and theory which investigates the effects of an opposing wind on stack ventilation driven by a constant source of heat within a space under displacement ventilation. We show that there is a critical wind speed, expressed in dimensionless terms as a critical Froude number, above which displacement ventilation is replaced by (less efficient) mixing ventilation with reversed flow. Below this critical speed, displacement ventilation, in which the interior has a two-layer stratification, is maintained. The criterion for the change in ventilation mode is derived from general considerations of mixing efficiencies in stratified flows. We conclude that even when wind effects might appear to be dominant, the inhibition of mixing by the stable stratification within the space ensures that stack ventilation can operate over a wide range of apparently adverse conditions.

  2. Night ventilation control strategies in office buildings

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wang, Zhaojun; Yi, Lingli; Gao, Fusheng

    2009-10-15

    In moderate climates night ventilation is an effective and energy-efficient approach to improve the indoor thermal environment for office buildings during the summer months, especially for heavyweight construction. However, is night ventilation a suitable strategy for office buildings with lightweight construction located in cold climates? In order to answer this question, the whole energy-consumption analysis software EnergyPlus was used to simulate the indoor thermal environment and energy consumption in typical office buildings with night mechanical ventilation in three cities in northern China. The summer outdoor climate data was analyzed, and three typical design days were chosen. The most important factorsmore » influencing night ventilation performance such as ventilation rates, ventilation duration, building mass and climatic conditions were evaluated. When night ventilation operation time is closer to active cooling time, the efficiency of night ventilation is higher. With night ventilation rate of 10 ach, the mean radiant temperature of the indoor surface decreased by up to 3.9 C. The longer the duration of operation, the more efficient the night ventilation strategy becomes. The control strategies for three locations are given in the paper. Based on the optimized strategies, the operation consumption and fees are calculated. The results show that more energy is saved in office buildings cooled by a night ventilation system in northern China than ones that do not employ this strategy. (author)« less

  3. 46 CFR 72.15-15 - Ventilation for closed spaces.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 3 2011-10-01 2011-10-01 false Ventilation for closed spaces. 72.15-15 Section 72.15-15... ARRANGEMENT Ventilation § 72.15-15 Ventilation for closed spaces. (a) All enclosed spaces within the vessel... spaces and for closing all doorways, ventilators and annular spaces around funnels and other openings to...

  4. 46 CFR 72.15-15 - Ventilation for closed spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 3 2013-10-01 2013-10-01 false Ventilation for closed spaces. 72.15-15 Section 72.15-15... ARRANGEMENT Ventilation § 72.15-15 Ventilation for closed spaces. (a) All enclosed spaces within the vessel... spaces and for closing all doorways, ventilators and annular spaces around funnels and other openings to...

  5. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop the ventilation, one of which may be the supply...

  6. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop the ventilation, one of which may be the supply...

  7. 46 CFR 108.181 - Ventilation for enclosed spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Ventilation for enclosed spaces. 108.181 Section 108.181... AND EQUIPMENT Construction and Arrangement Ventilation § 108.181 Ventilation for enclosed spaces. (a) Each enclosed space must be vented or ventilated. (b) There must be a means to close each vent or...

  8. 46 CFR 108.181 - Ventilation for enclosed spaces.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Ventilation for enclosed spaces. 108.181 Section 108.181... AND EQUIPMENT Construction and Arrangement Ventilation § 108.181 Ventilation for enclosed spaces. (a) Each enclosed space must be vented or ventilated. (b) There must be a means to close each vent or...

  9. 46 CFR 72.15-15 - Ventilation for closed spaces.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Ventilation for closed spaces. 72.15-15 Section 72.15-15... ARRANGEMENT Ventilation § 72.15-15 Ventilation for closed spaces. (a) All enclosed spaces within the vessel... spaces and for closing all doorways, ventilators and annular spaces around funnels and other openings to...

  10. 46 CFR 72.15-15 - Ventilation for closed spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 3 2014-10-01 2014-10-01 false Ventilation for closed spaces. 72.15-15 Section 72.15-15... ARRANGEMENT Ventilation § 72.15-15 Ventilation for closed spaces. (a) All enclosed spaces within the vessel... spaces and for closing all doorways, ventilators and annular spaces around funnels and other openings to...

  11. 46 CFR 108.181 - Ventilation for enclosed spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Ventilation for enclosed spaces. 108.181 Section 108.181... AND EQUIPMENT Construction and Arrangement Ventilation § 108.181 Ventilation for enclosed spaces. (a) Each enclosed space must be vented or ventilated. (b) There must be a means to close each vent or...

  12. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop the ventilation, one of which may be the supply...

  13. 46 CFR 108.181 - Ventilation for enclosed spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Ventilation for enclosed spaces. 108.181 Section 108.181... AND EQUIPMENT Construction and Arrangement Ventilation § 108.181 Ventilation for enclosed spaces. (a) Each enclosed space must be vented or ventilated. (b) There must be a means to close each vent or...

  14. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop the ventilation, one of which may be the supply...

  15. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop the ventilation, one of which may be the supply...

  16. 46 CFR 108.181 - Ventilation for enclosed spaces.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Ventilation for enclosed spaces. 108.181 Section 108.181... AND EQUIPMENT Construction and Arrangement Ventilation § 108.181 Ventilation for enclosed spaces. (a) Each enclosed space must be vented or ventilated. (b) There must be a means to close each vent or...

  17. 46 CFR 72.15-15 - Ventilation for closed spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 3 2012-10-01 2012-10-01 false Ventilation for closed spaces. 72.15-15 Section 72.15-15... ARRANGEMENT Ventilation § 72.15-15 Ventilation for closed spaces. (a) All enclosed spaces within the vessel... spaces and for closing all doorways, ventilators and annular spaces around funnels and other openings to...

  18. 46 CFR 190.15-15 - Ventilation for living spaces and quarters.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Ventilation for living spaces and quarters. 190.15-15... VESSELS CONSTRUCTION AND ARRANGEMENT Ventilation § 190.15-15 Ventilation for living spaces and quarters. (a) All living spaces shall be adequately ventilated in a manner suitable to the purpose of the space...

  19. 46 CFR 190.15-15 - Ventilation for living spaces and quarters.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Ventilation for living spaces and quarters. 190.15-15... VESSELS CONSTRUCTION AND ARRANGEMENT Ventilation § 190.15-15 Ventilation for living spaces and quarters. (a) All living spaces shall be adequately ventilated in a manner suitable to the purpose of the space...

  20. 46 CFR 190.15-15 - Ventilation for living spaces and quarters.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Ventilation for living spaces and quarters. 190.15-15... VESSELS CONSTRUCTION AND ARRANGEMENT Ventilation § 190.15-15 Ventilation for living spaces and quarters. (a) All living spaces shall be adequately ventilated in a manner suitable to the purpose of the space...

  1. 46 CFR 190.15-15 - Ventilation for living spaces and quarters.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Ventilation for living spaces and quarters. 190.15-15... VESSELS CONSTRUCTION AND ARRANGEMENT Ventilation § 190.15-15 Ventilation for living spaces and quarters. (a) All living spaces shall be adequately ventilated in a manner suitable to the purpose of the space...

  2. 46 CFR 190.15-15 - Ventilation for living spaces and quarters.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Ventilation for living spaces and quarters. 190.15-15... VESSELS CONSTRUCTION AND ARRANGEMENT Ventilation § 190.15-15 Ventilation for living spaces and quarters. (a) All living spaces shall be adequately ventilated in a manner suitable to the purpose of the space...

  3. Investigation of turbine ventilator performance after added wind cup for room exhaust air applications

    NASA Astrophysics Data System (ADS)

    Harun, D.; Zulfadhli; Akhyar, H.

    2018-05-01

    The turbine ventilator is a wind turbine with a vertical axis that has a combined function of the wind turbine and a suction fan. In this study, the turbine ventilator modified by adding a wind cup on the top (cap) turbine ventilator. The purpose of this experiment is to investigated the effect of the addition of wind cup on the turbine ventilator. Turbine ventilator used is type v30 and wind cup with diameter 77 mm. The experiment was conducted using a triangular pentagon model space chamber which was cut off to place the ventilator turbine ventilation cup with a volume of 0.983 m3 (equivalent to 1 mm3). The results of this study indicate that at an average wind speed of 1.8 m/s, the rotation of the turbine produced without a wind cup is 60.6 rpm while with the addition of a wind cup in the turbine ventilator is 69 rpm. The average increase of rotation turbine after added win cup is 8.4 rpm and the efficiency improvement of turbine ventilator is 1.7 %.

  4. Analysis on ventilation pressure of fire area in longitudinal ventilation of underground tunnel

    NASA Astrophysics Data System (ADS)

    Li, Jiaxin; Li, Yanfeng; Feng, Xiao; Li, Junmei

    2018-03-01

    In order to solve the problem of ventilation pressure loss in the fire area under the fire condition, the wind pressure loss model of the fire area is established based on the thermodynamic equilibrium relation. The semi-empirical calculation formula is obtained by using the model experiment and CFD simulation. The validity of the formula is verified. The results show that the ventilation pressure loss in the fire zone is proportional to the convective heat release rate at the critical velocity, which is inversely proportional to the upstream ventilation velocity and the tunnel cross-sectional area. The proposed formula is consistent with the law of the tunnel fire test fitting formula that results are close, in contrast, the advantage lies in a clear theoretical basis and ventilation velocity values. The resistance of road tunnel ventilation system is calculated accurately and reliably, and then an effective emergency ventilation operation program is developed. It is necessary to consider the fire zone ventilation pressure loss. The proposed ventilation pressure loss formula can be used for design calculation after thorough verification.

  5. Conservative fluid management prevents age-associated ventilator induced mortality.

    PubMed

    Herbert, Joseph A; Valentine, Michael S; Saravanan, Nivi; Schneck, Matthew B; Pidaparti, Ramana; Fowler, Alpha A; Reynolds, Angela M; Heise, Rebecca L

    2016-08-01

    Approximately 800 thousand patients require mechanical ventilation in the United States annually with an in-hospital mortality rate of over 30%. The majority of patients requiring mechanical ventilation are over the age of 65 and advanced age is known to increase the severity of ventilator-induced lung injury (VILI) and in-hospital mortality rates. However, the mechanisms which predispose aging ventilator patients to increased mortality rates are not fully understood. Ventilation with conservative fluid management decreases mortality rates in acute respiratory distress patients, but to date there has been no investigation of the effect of conservative fluid management on VILI and ventilator associated mortality rates. We hypothesized that age-associated increases in susceptibility and incidence of pulmonary edema strongly promote age-related increases in ventilator associated mortality. 2month old and 20month old male C57BL6 mice were mechanically ventilated with either high tidal volume (HVT) or low tidal volume (LVT) for up to 4h with either liberal or conservative fluid support. During ventilation, lung compliance, total lung capacity, and hysteresis curves were quantified. Following ventilation, bronchoalveolar lavage fluid was analyzed for total protein content and inflammatory cell infiltration. Wet to dry ratios were used to directly measure edema in excised lungs. Lung histology was performed to quantify alveolar barrier damage/destruction. Age matched non-ventilated mice were used as controls. At 4h, both advanced age and HVT ventilation significantly increased markers of inflammation and injury, degraded pulmonary mechanics, and decreased survival rates. Conservative fluid support significantly diminished pulmonary edema and improved pulmonary mechanics by 1h in advanced age HVT subjects. In 4h ventilations, conservative fluid support significantly diminished pulmonary edema, improved lung mechanics, and resulted in significantly lower mortality rates in older subjects. Our study demonstrates that conservative fluid alone can attenuate the age associated increase in ventilator associated mortality. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Oral mask ventilation is more effective than face mask ventilation after nasal surgery.

    PubMed

    Yazicioğlu, Dilek; Baran, Ilkay; Uzumcugil, Filiz; Ozturk, Ibrahim; Utebey, Gulten; Sayın, M Murat

    2016-06-01

    To evaluate and compare the face mask (FM) and oral mask (OM) ventilation techniques during anesthesia emergence regarding tidal volume, leak volume, and difficult mask ventilation (DMV) incidence. Prospective, randomized, crossover study. Operating room, training and research hospital. American Society of Anesthesiologists physical status I and II adult patients scheduled for nasal surgery. Patients in group FM-OM received FM ventilation first, followed by OM ventilation, and patients in group OM-FM received OM ventilation first, followed by FM ventilation, with spontaneous ventilation after deep extubation. The FM ventilation was applied with the 1-handed EC-clamp technique. The OM was placed only over the mouth, and the 1-handed EC-clamp technique was used again. A child's size FM was used for the OM ventilation technique, the mask was rotated, and the inferior part of the mask was placed toward the nose. The leak volume (MVleak), mean airway pressure (Pmean), and expired tidal volume (TVe) were assessed with each mask technique for 3 consecutive breaths. A mask ventilation grade ≥3 was considered DMV. DMV occurred more frequently during FM ventilation (75% with FM vs 8% with OM). In the FM-first sequence, the mean TVe was 249±61mL with the FM and 455±35mL with the OM (P=.0001), whereas in the OM-first sequence, it was 276±81mL with the FM and 409±37mL with the OM (P=.0001). Regardless of the order used, the OM technique significantly decreased the MVleak and increased the TVe when compared to the FM technique. During anesthesia emergence after nasal surgery the OM may offer an effective ventilation method as it decreases the incidence of DMV and the gas leak around the mask and provides higher tidal volume delivery compared with FM ventilation. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Invasive Mechanical Ventilation and Mortality in Pediatric Hematopoietic Stem Cell Transplantation: A Multicenter Study.

    PubMed

    Rowan, Courtney M; Gertz, Shira J; McArthur, Jennifer; Fitzgerald, Julie C; Nitu, Mara E; Loomis, Ashley; Hsing, Deyin D; Duncan, Christine N; Mahadeo, Kris M; Smith, Lincoln S; Moffet, Jerelyn; Hall, Mark W; Pinos, Emily L; Cheifetz, Ira M; Tamburro, Robert F

    2016-04-01

    To establish the current respiratory practice patterns in pediatric hematopoietic stem cell transplant patients and investigate their associations with mortality across multiple centers. Retrospective cohort between 2009 and 2014. Twelve children's hospitals in the United States. Two hundred twenty-two pediatric allogeneic hematopoietic stem cell transplant recipients with acute respiratory failure using invasive mechanical ventilation. None. PICU mortality of our cohort was 60.4%. Mortality at 180 days post PICU discharge was 74%. Length of PICU stay prior to initiation of invasive mechanical ventilation was significantly lower in survivors, and the odds of mortality increased for longer length of PICU stay prior to intubation. A total of 91 patients (41%) received noninvasive ventilation at some point during their PICU stay prior to intubation. Noninvasive ventilation use preintubation was associated with increased mortality (odds ratio, 2.1; 95% CI, 1.2-3.6; p = 0.010). Patients ventilated longer than 15 days had higher odds of death (odds ratio, 2.4; 95% CI, 1.3-4.2; p = 0.004). Almost 40% of patients (n = 85) were placed on high-frequency oscillatory ventilation with a mortality of 76.5% (odds ratio, 3.3; 95% CI, 1.7-6.5; p = 0.0004). Of the 20 patients who survived high-frequency oscillatory ventilation, 18 were placed on high-frequency oscillatory ventilation no later than the third day of invasive mechanical ventilation. In this subset of 85 patients, transition to high-frequency oscillatory ventilation within 2 days of the start of invasive mechanical ventilation resulted in a 76% decrease in the odds of death compared with those who transitioned to high-frequency oscillatory ventilation later in the invasive mechanical ventilation course. This study suggests that perhaps earlier more aggressive critical care interventions in the pediatric hematopoietic stem cell transplant patient with respiratory failure requiring invasive mechanical ventilation may offer an opportunity to improve outcomes.

  8. Conservative Fluid Management Prevents Age-Associated Ventilator Induced Mortality

    PubMed Central

    Herbert, Joseph A.; Valentine, Michael S.; Saravanan, Nivi; Schneck, Matthew B.; Pidaparti, Ramana; Fowler, Alpha A.; Reynolds, Angela M.; Heise, Rebecca L.

    2017-01-01

    Background Approximately 800 thousand patients require mechanical ventilation in the United States annually with an in-hospital mortality rate of over 30%. The majority of patients requiring mechanical ventilation are over the age of 65 and advanced age is known to increase the severity of ventilator-induced lung injury (VILI) and in-hosptial mortality rates. However, the mechanisms which predispose aging ventilator patients to increased mortality rates are not fully understood. Ventilation with conservative fluid management decreases mortality rates in acute respiratory distress patients, but to date there has been no investigation of the effect of conservative fluid management on VILI and ventilator associated mortality rates. We hypothesized that age-associated increases in susceptibility and incidence of pulmonary edema strongly promote age-related increases in ventilator associated mortality. Methods 2 month old and 20 month old male C57BL6 mice were mechanically ventilated with either high tidal volume (HVT) or low tidal volume (LVT) for up to 4 hours with either liberal or conservative fluid support. During ventilation, lung compliance, total lung capacity, and hysteresis curves were quantified. Following ventilation, bronchoalveolar lavage fluid was analyzed for total protein content and inflammatory cell infiltration. Wet to dry ratios were used to directly measure edema in excised lungs. Lung histology was performed to quantify alveolar barrier damage/destruction. Age matched non-ventilated mice were used as controls. Results At 4hrs, both advanced age and HVT ventilation significantly increased markers of inflammation and injury, degraded pulmonary mechanics, and decreased survival rates. Conservative fluid support significantly diminished pulmonary edema and improved pulmonary mechanics by 1hr in advanced age HVT subjects. In 4hr ventilations, conservative fluid support significantly diminished pulmonary edema, improved lung mechanics, and resulted in significantly lower mortality rates in older subjects. Conclusion Our study demonstrates that conservative fluid alone can attenuate the age associated increase in ventilator associated mortality. PMID:27188767

  9. History of Mechanical Ventilation. From Vesalius to Ventilator-induced Lung Injury.

    PubMed

    Slutsky, Arthur S

    2015-05-15

    Mechanical ventilation is a life-saving therapy that catalyzed the development of modern intensive care units. The origins of modern mechanical ventilation can be traced back about five centuries to the seminal work of Andreas Vesalius. This article is a short history of mechanical ventilation, tracing its origins over the centuries to the present day. One of the great advances in ventilatory support over the past few decades has been the development of lung-protective ventilatory strategies, based on our understanding of the iatrogenic consequences of mechanical ventilation such as ventilator-induced lung injury. These strategies have markedly improved clinical outcomes in patients with respiratory failure.

  10. Efficacy of an expanded ventilator bundle for the reduction of ventilator-associated pneumonia in the medical intensive care unit.

    PubMed

    Blamoun, John; Alfakir, Maria; Rella, Marie E; Wojcik, Janice M; Solis, Roberto A; Anees Khan, M; DeBari, Vincent A

    2009-03-01

    The ventilator bundle (VB) includes a group of clinical maneuvers (head-of-bed elevation, "sedation vacation," deep vein thrombosis prophylaxis, and peptic ulcer disease prophylaxis) to improve outcomes in patients undergoing mechanical ventilation. We modified the standard VB in our medical intensive care unit to include a group of respiratory therapist-driven protocols and, postimplementation, observed a statistically significant (P = .0006) reduction in ventilator-associated pneumonia (VAP), from a median of 14.1 cases/10(3) ventilator-days (interquartile range [IQR] = 12.1 to 20.6) to 0 cases/10(3) ventilator-days (IQR = 0 to 1.1).

  11. Nasal mask ventilation is better than face mask ventilation in edentulous patients.

    PubMed

    Kapoor, Mukul Chandra; Rana, Sandeep; Singh, Arvind Kumar; Vishal, Vindhya; Sikdar, Indranil

    2016-01-01

    Face mask ventilation of the edentulous patient is often difficult as ineffective seating of the standard mask to the face prevents attainment of an adequate air seal. The efficacy of nasal ventilation in edentulous patients has been cited in case reports but has never been investigated. Consecutive edentulous adult patients scheduled for surgery under general anesthesia with endotracheal intubation, during a 17-month period, were prospectively evaluated. After induction of anesthesia and administration of neuromuscular blocker, lungs were ventilated with a standard anatomical face mask of appropriate size, using a volume controlled anesthesia ventilator with tidal volume set at 10 ml/kg. In case of inadequate ventilation, the mask position was adjusted to achieve best-fit. Inspired and expired tidal volumes were measured. Thereafter, the face mask was replaced by a nasal mask and after achieving best-fit, the inspired and expired tidal volumes were recorded. The difference in expired tidal volumes and airway pressures at best-fit with the use of the two masks and number of patients with inadequate ventilation with use of the masks were statistically analyzed. A total of 79 edentulous patients were recruited for the study. The difference in expiratory tidal volumes with the use of the two masks at best-fit was statistically significant (P = 0.0017). Despite the best-fit mask placement, adequacy of ventilation could not be achieved in 24.1% patients during face mask ventilation, and 12.7% patients during nasal mask ventilation and the difference was statistically significant. Nasal mask ventilation is more efficient than standard face mask ventilation in edentulous patients.

  12. Mechanical Ventilation in Acute Hypoxemic Respiratory Failure: A Review of New Strategies for the Practicing Hospitalist

    PubMed Central

    Wilson, Jennifer G.; Matthay, Michael A.

    2014-01-01

    BACKGROUND The goal of mechanical ventilation in acute hypoxemic respiratory failure is to support adequate gas exchange without harming the lungs. How patients are mechanically ventilated can significantly impact their ultimate outcomes. METHODS This review focuses on emerging evidence regarding strategies for mechanical ventilation in patients with acute hypoxemic respiratory failure including: low tidal volume ventilation in the acute respiratory distress syndrome (ARDS), novel ventilator modes as alternatives to low tidal volume ventilation, adjunctive strategies that may enhance recovery in ARDS, the use of lung-protective strategies in patients without ARDS, rescue therapies in refractory hypoxemia, and an evidence-based approach to weaning from mechanical ventilation. RESULTS Once a patient is intubated and mechanically ventilated, low tidal volume ventilation remains the best strategy in ARDS. Adjunctive therapies in ARDS include a conservative fluid management strategy, as well as neuromuscular blockade and prone positioning in moderate-to-severe disease. There is also emerging evidence that a lung-protective strategy may benefit non-ARDS patients. For patients with refractory hypoxemia, extracorporeal membrane oxygenation should be considered. Once the patient demonstrates signs of recovery, the best approach to liberation from mechanical ventilation involves daily spontaneous breathing trials and protocolized assessment of readiness for extubation. CONCLUSIONS Prompt recognition of ARDS and use of lung-protective ventilation, as well as evidence-based adjunctive therapies, remain the cornerstones of caring for patients with acute hypoxemic respiratory failure. In the absence of contraindications, it is reasonable to consider lung-protective ventilation in non-ARDS patients as well, though the evidence supporting this practice is less conclusive. PMID:24733692

  13. High tidal volume ventilation induces NOS2 and impairs cAMP- dependent air space fluid clearance.

    PubMed

    Frank, James A; Pittet, Jean-Francois; Lee, Hyon; Godzich, Micaela; Matthay, Michael A

    2003-05-01

    Tidal volume reduction during mechanical ventilation reduces mortality in patients with acute lung injury and the acute respiratory distress syndrome. To determine the mechanisms underlying the protective effect of low tidal volume ventilation, we studied the time course and reversibility of ventilator-induced changes in permeability and distal air space edema fluid clearance in a rat model of ventilator-induced lung injury. Anesthetized rats were ventilated with a high tidal volume (30 ml/kg) or with a high tidal volume followed by ventilation with a low tidal volume of 6 ml/kg. Endothelial and epithelial protein permeability were significantly increased after high tidal volume ventilation but returned to baseline levels when tidal volume was reduced. The basal distal air space fluid clearance (AFC) rate decreased by 43% (P < 0.05) after 1 h of high tidal volume but returned to the preventilation rate 2 h after tidal volume was reduced. Not all of the effects of high tidal volume ventilation were reversible. The cAMP-dependent AFC rate after 1 h of 30 ml/kg ventilation was significantly reduced and was not restored when tidal volume was reduced. High tidal volume ventilation also increased lung inducible nitric oxide synthase (NOS2) expression and air space total nitrite at 3 h. Inhibition of NOS2 activity preserved cAMP-dependent AFC. Because air space edema fluid inactivates surfactant and reduces ventilated lung volume, the reduction of cAMP-dependent AFC by reactive nitrogen species may be an important mechanism of clinical ventilator-associated lung injury.

  14. The influence of temperature on fatigue-crack growth in a mill-annealed Ti-6Al-4V alloy

    NASA Technical Reports Server (NTRS)

    Wei, R. P.; Ritter, D. L.

    1971-01-01

    To understand the influence of temperature on the rate of fatigue crack growth in high strength metal alloys, constant load amplitude fatigue crack growth experiments were carried out using a 1/4 inch thick (6.35 mm) mill-annealed Ti-6Al-4V alloy plate as a model material. The rates of fatigue crack growth were determined as a function of temperature, ranging from room temperature to about 290 C and as a function of the crack tip, stress intensity factor K, in dehumidified high purity argon environment. The dependence of the rate of fatigue crack growth on K appears to be separable into two regions. The transition correlates with changes in both the microscopic and macroscopic appearances of the fracture surfaces, and suggests a change in the mechanism and the influence of microstructure on fatigue crack growth.

  15. An experimental aluminum-fueled power plant

    NASA Astrophysics Data System (ADS)

    Vlaskin, M. S.; Shkolnikov, E. I.; Bersh, A. V.; Zhuk, A. Z.; Lisicyn, A. V.; Sorokovikov, A. I.; Pankina, Yu. V.

    2011-10-01

    An experimental co-generation power plant (CGPP-10) using aluminum micron powder (with average particle size up to 70 μm) as primary fuel and water as primary oxidant was developed and tested. Power plant can work in autonomous (unconnected from industrial network) nonstop regime producing hydrogen, electrical energy and heat. One of the key components of experimental plant is aluminum-water high-pressure reactor projected for hydrogen production rate of ∼10 nm3 h-1. Hydrogen from the reactor goes through condenser and dehumidifier and with -25 °C dew-point temperature enters into the air-hydrogen fuel cell 16 kW-battery. From 1 kg of aluminum the experimental plant produces 1 kWh of electrical energy and 5-7 kWh of heat. Power consumer gets about 10 kW of electrical power. Plant electrical and total efficiencies are 12% and 72%, respectively.

  16. Evaluation of food drying with air dehumidification system: a short review

    NASA Astrophysics Data System (ADS)

    Djaeni, M.; Utari, F. D.; Sasongko, S. B.; Kumoro, A. C.

    2018-01-01

    Energy efficient drying for food and agriculture products resulting high quality products has been an important issue. Currently, about 50% of total energy for postharvest treatment was used for drying. This paper presents the evaluation of new approach namely air dehumidification system with zeolite for food drying. Zeolite is a material having affinity to water in which reduced the moisture in air. With low moisture content and relative humidity, the air can improve driving force for drying even at low temperature. Thus, the energy efficiency can be potentially enhanced and the product quality can be well retained. For proving the hypothesis, the paddy and onion have been dried using dehumidified air. As performance indicators, the drying time, product quality, and heat efficiency were evaluated. Results indicated that the drying with zeolite improved the performances significantly. At operating temperature ranging 50 - 60°C, the efficiency of drying system can reach 75% with reasonable product quality.

  17. Water-vapor effects on friction of magnetic tape in contact with nickel-zinc ferrite

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Buckley, D. H.

    1984-01-01

    The effects of humidity of moist nitrogen on the friction and deformation behavior of magnetic tape in contact with a nickel-zinc ferrite spherical pin were studied. The results indicate that the coefficient of friction is markedly dependent on the ambient relative humidity. Although the coefficient of friction remains low below 40-percent relative humidity, it increases rapidly with increasing relative humidity above 40 percent. The general ambient environment of the tape does not have any effect on the friction behavior if the area where the tape is in sliding contact with the ferrite pin is flooded with controlled nitrogen. The response time for the friction of the tape to humidity changes is about 10 sec. The effect of friction as a function of relative humidity on dehumidifying is very similar to that on humidifying. A surface softening of the tape due to water vapor increases the friction of the tape.

  18. Technology advancement of the static feed water electrolysis process

    NASA Technical Reports Server (NTRS)

    Schubert, F. H.; Wynveen, R. A.

    1977-01-01

    A program to advance the technology of oxygen- and hydrogen-generating subsystems based on water electrolysis was studied. Major emphasis was placed on static feed water electrolysis, a concept characterized by low power consumption and high intrinsic reliability. The static feed based oxygen generation subsystem consists basically of three subassemblies: (1) a combined water electrolysis and product gas dehumidifier module; (2) a product gas pressure controller and; (3) a cyclically filled water feed tank. Development activities were completed at the subsystem as well as at the component level. An extensive test program including single cell, subsystem and integrated system testing was completed with the required test support accessories designed, fabricated, and assembled. Mini-product assurance activities were included throughout all phases of program activities. An extensive number of supporting technology studies were conducted to advance the technology base of the static feed water electrolysis process and to resolve problems.

  19. Vacuum FTIR observation on hygroscopic properties and phase transition of malonic acid aerosols

    NASA Astrophysics Data System (ADS)

    Shao, Xu; Zhang, Yun; Pang, Shu-Feng; Zhang, Yun-Hong

    2017-02-01

    A novel approach based on a combination of a pulse relative humidity (RH) controlling system and a rapid scan vacuum FTIR spectrometer was utilized to investigate the hygroscopic property and phase transition of malonic acid (MA) aerosols. By using this approach, both water vapor amount around the aerosols and water content within aerosols with sub-second time resolution were obtained. Based on the features of FTIR absorbing bands, it can be known that the evolution of hydrogen-bonding structures of malonic acid aerosols took place from (H2O)n-MA to MA-MA accompanying with phase transition in the dehumidifying process. And in present paper, the stepwise efflorescence of MA aerosols and nucleation rates at different RHs are first reported. Our observation has shown that the efflorescence of MA started at ∼17% RH and the nucleation rates increased with decreasing RH.

  20. Using liquid desiccant as a regenerable filter for capturing and deactivating contaminants

    DOEpatents

    Slayzak, Steven J.; Anderson, Ren S.; Judkoff, Ronald D.; Blake, Daniel M.; Vinzant, Todd B.; Ryan, Joseph P.

    2007-12-11

    A method, and systems for implementing such method, for purifying and conditioning air of weaponized contaminants. The method includes wetting a filter packing media with a salt-based liquid desiccant, such as water with a high concentration of lithium chloride. Air is passed through the wetted filter packing media and the contaminants in are captured with the liquid desiccant while the liquid desiccant dehumidifies the air. The captured contaminants are then deactivated in the liquid desiccant, which may include heating the liquid desiccant. The liquid desiccant is regenerated by applying heat to the liquid desiccant and then removing moisture. The method includes repeating the wetting with the regenerated liquid desiccant which provides a regenerable filtering process that captures and deactivates contaminants on an ongoing basis while also conditioning the air. The method may include filtration effectiveness enhancement by electrostatic or inertial means.

  1. The comparison of manual and LabVIEW-based fuzzy control on mechanical ventilation.

    PubMed

    Guler, Hasan; Ata, Fikret

    2014-09-01

    The aim of this article is to develop a knowledge-based therapy for management of rats with respiratory distress. A mechanical ventilator was designed to achieve this aim. The designed ventilator is called an intelligent mechanical ventilator since fuzzy logic was used to control the pneumatic equipment according to the rat's status. LabVIEW software was used to control all equipments in the ventilator prototype and to monitor respiratory variables in the experiment. The designed ventilator can be controlled both manually and by fuzzy logic. Eight female Wistar-Albino rats were used to test the designed ventilator and to show the effectiveness of fuzzy control over manual control on pressure control ventilation mode. The anesthetized rats were first ventilated for 20 min manually. After that time, they were ventilated for 20 min by fuzzy logic. Student's t-test for p < 0.05 was applied to the measured minimum, maximum and mean peak inspiration pressures to analyze the obtained results. The results show that there is no statistical difference in the rat's lung parameters before and after the experiments. It can be said that the designed ventilator and developed knowledge-based therapy support artificial respiration of living things successfully. © IMechE 2014.

  2. Application of mid-frequency ventilation in an animal model of lung injury: a pilot study.

    PubMed

    Mireles-Cabodevila, Eduardo; Chatburn, Robert L; Thurman, Tracy L; Zabala, Luis M; Holt, Shirley J; Swearingen, Christopher J; Heulitt, Mark J

    2014-11-01

    Mid-frequency ventilation (MFV) is a mode of pressure control ventilation based on an optimal targeting scheme that maximizes alveolar ventilation and minimizes tidal volume (VT). This study was designed to compare the effects of conventional mechanical ventilation using a lung-protective strategy with MFV in a porcine model of lung injury. Our hypothesis was that MFV can maximize ventilation at higher frequencies without adverse consequences. We compared ventilation and hemodynamic outcomes between conventional ventilation and MFV. This was a prospective study of 6 live Yorkshire pigs (10 ± 0.5 kg). The animals were subjected to lung injury induced by saline lavage and injurious conventional mechanical ventilation. Baseline conventional pressure control continuous mandatory ventilation was applied with V(T) = 6 mL/kg and PEEP determined using a decremental PEEP trial. A manual decision support algorithm was used to implement MFV using the same conventional ventilator. We measured P(aCO2), P(aO2), end-tidal carbon dioxide, cardiac output, arterial and venous blood oxygen saturation, pulmonary and systemic vascular pressures, and lactic acid. The MFV algorithm produced the same minute ventilation as conventional ventilation but with lower V(T) (-1 ± 0.7 mL/kg) and higher frequency (32.1 ± 6.8 vs 55.7 ± 15.8 breaths/min, P < .002). There were no differences between conventional ventilation and MFV for mean airway pressures (16.1 ± 1.3 vs 16.4 ± 2 cm H2O, P = .75) even when auto-PEEP was higher (0.6 ± 0.9 vs 2.4 ± 1.1 cm H2O, P = .02). There were no significant differences in any hemodynamic measurements, although heart rate was higher during MFV. In this pilot study, we demonstrate that MFV allows the use of higher breathing frequencies and lower V(T) than conventional ventilation to maximize alveolar ventilation. We describe the ventilatory or hemodynamic effects of MFV. We also demonstrate that the application of a decision support algorithm to manage MFV is feasible. Copyright © 2014 by Daedalus Enterprises.

  3. 46 CFR 32.55-5 - Ventilation of tank vessels constructed between November 10, 1936, and July 1, 1951-TB/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... actuated gas ejectors or blowers or ventilators fitted with heads for natural ventilation, will be approved... 46 Shipping 1 2010-10-01 2010-10-01 false Ventilation of tank vessels constructed between November... HOMELAND SECURITY TANK VESSELS SPECIAL EQUIPMENT, MACHINERY, AND HULL REQUIREMENTS Ventilation and Venting...

  4. 46 CFR 92.15-10 - Ventilation for closed spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Ventilation for closed spaces. 92.15-10 Section 92.15-10... CONSTRUCTION AND ARRANGEMENT Ventilation § 92.15-10 Ventilation for closed spaces. (a) Except as noted in paragraph (c) of this section, all enclosed spaces within the vessel shall be properly vented or ventilated...

  5. 46 CFR 92.15-10 - Ventilation for closed spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Ventilation for closed spaces. 92.15-10 Section 92.15-10... CONSTRUCTION AND ARRANGEMENT Ventilation § 92.15-10 Ventilation for closed spaces. (a) Except as noted in paragraph (c) of this section, all enclosed spaces within the vessel shall be properly vented or ventilated...

  6. 46 CFR 92.15-10 - Ventilation for closed spaces.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Ventilation for closed spaces. 92.15-10 Section 92.15-10... CONSTRUCTION AND ARRANGEMENT Ventilation § 92.15-10 Ventilation for closed spaces. (a) Except as noted in paragraph (c) of this section, all enclosed spaces within the vessel shall be properly vented or ventilated...

  7. 46 CFR 92.15-10 - Ventilation for closed spaces.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Ventilation for closed spaces. 92.15-10 Section 92.15-10... CONSTRUCTION AND ARRANGEMENT Ventilation § 92.15-10 Ventilation for closed spaces. (a) Except as noted in paragraph (c) of this section, all enclosed spaces within the vessel shall be properly vented or ventilated...

  8. 46 CFR 92.15-10 - Ventilation for closed spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Ventilation for closed spaces. 92.15-10 Section 92.15-10... CONSTRUCTION AND ARRANGEMENT Ventilation § 92.15-10 Ventilation for closed spaces. (a) Except as noted in paragraph (c) of this section, all enclosed spaces within the vessel shall be properly vented or ventilated...

  9. Intraoperative mechanical ventilation for the pediatric patient.

    PubMed

    Kneyber, Martin C J

    2015-09-01

    Invasive mechanical ventilation is required when children undergo general anesthesia for any procedure. It is remarkable that one of the most practiced interventions such as pediatric mechanical ventilation is hardly supported by any scientific evidence but rather based on personal experience and data from adults, especially as ventilation itself is increasingly recognized as a harmful intervention that causes ventilator-induced lung injury. The use of low tidal volume and higher levels of positive end-expiratory pressure became an integral part of lung-protective ventilation following the outcomes of clinical trials in critically ill adults. This approach has been readily adopted in pediatric ventilation. However, a clear association between tidal volume and mortality has not been ascertained in pediatrics. In fact, experimental studies have suggested that young children might be less susceptible to ventilator-induced lung injury. As such, no recommendations on optimal lung-protective ventilation strategy in children with or without lung injury can be made. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Trends in mechanical ventilation: are we ventilating our patients in the best possible way?

    PubMed

    Dellaca', Raffaele L; Veneroni, Chiara; Farre', Ramon

    2017-06-01

    This review addresses how the combination of physiology, medicine and engineering principles contributed to the development and advancement of mechanical ventilation, emphasising the most urgent needs for improvement and the most promising directions of future development. Several aspects of mechanical ventilation are introduced, highlighting on one side the importance of interdisciplinary research for further development and, on the other, the importance of training physicians sufficiently on the technological aspects of modern devices to exploit properly the great complexity and potentials of this treatment. To learn how mechanical ventilation developed in recent decades and to provide a better understanding of the actual technology and practice.To learn how and why interdisciplinary research and competences are necessary for providing the best ventilation treatment to patients.To understand which are the most relevant technical limitations in modern mechanical ventilators that can affect their performance in delivery of the treatment.To better understand and classify ventilation modes.To learn the classification, benefits, drawbacks and future perspectives of automatic ventilation tailoring algorithms.

  11. [Cases and duration of mechanical ventilation in German hospitals : An analysis of DRG incentives and developments in respiratory medicine].

    PubMed

    Biermann, A; Geissler, A

    2016-09-01

    Diagnosis-related groups (DRGs) have been used to reimburse hospitals services in Germany since 2003/04. Like any other reimbursement system, DRGs offer specific incentives for hospitals that may lead to unintended consequences for patients. In the German context, specific procedures and their documentation are suspected to be primarily performed to increase hospital revenues. Mechanical ventilation of patients and particularly the duration of ventilation, which is an important variable for the DRG-classification, are often discussed to be among these procedures. The aim of this study was to examine incentives created by the German DRG-based payment system with regard to mechanical ventilation and to identify factors that explain the considerable increase of mechanically ventilated patients in recent years. Moreover, the assumption that hospitals perform mechanical ventilation in order to gain economic benefits was examined. In order to gain insights on the development of the number of mechanically ventilated patients, patient-level data provided by the German Federal Statistical Office and the German Institute for the Hospital Remuneration System were analyzed. The type of performed ventilation, the total number of ventilation hours, the age distribution, mortality and the DRG distribution for mechanical ventilation were calculated, using methods of descriptive and inferential statistics. Furthermore, changes in DRG-definitions and changes in respiratory medicine were compared for the years 2005-2012. Since the introduction of the DRG-based payment system in Germany, the hours of ventilation and the number of mechanically ventilated patients have substantially increased, while mortality has decreased. During the same period there has been a switch to less invasive ventilation methods. The age distribution has shifted to higher age-groups. A ventilation duration determined by DRG definitions could not be found. Due to advances in respiratory medicine, new ventilation methods have been introduced that are less prone to complications. This development has simultaneously improved survival rates. There was no evidence supporting the assumption that the duration of mechanical ventilation is influenced by the time intervals relevant for DRG grouping. However, presumably operational routines such as staff availability within early and late shifts of the hospital have a significant impact on the termination of mechanical ventilation.

  12. Higher levels of spontaneous breathing reduce lung injury in experimental moderate acute respiratory distress syndrome.

    PubMed

    Carvalho, Nadja C; Güldner, Andreas; Beda, Alessandro; Rentzsch, Ines; Uhlig, Christopher; Dittrich, Susanne; Spieth, Peter M; Wiedemann, Bärbel; Kasper, Michael; Koch, Thea; Richter, Torsten; Rocco, Patricia R; Pelosi, Paolo; de Abreu, Marcelo Gama

    2014-11-01

    To assess the effects of different levels of spontaneous breathing during biphasic positive airway pressure/airway pressure release ventilation on lung function and injury in an experimental model of moderate acute respiratory distress syndrome. Multiple-arm randomized experimental study. University hospital research facility. Thirty-six juvenile pigs. Pigs were anesthetized, intubated, and mechanically ventilated. Moderate acute respiratory distress syndrome was induced by repetitive saline lung lavage. Biphasic positive airway pressure/airway pressure release ventilation was conducted using the airway pressure release ventilation mode with an inspiratory/expiratory ratio of 1:1. Animals were randomly assigned to one of four levels of spontaneous breath in total minute ventilation (n = 9 per group, 6 hr each): 1) biphasic positive airway pressure/airway pressure release ventilation, 0%; 2) biphasic positive airway pressure/airway pressure release ventilation, > 0-30%; 3) biphasic positive airway pressure/airway pressure release ventilation, > 30-60%, and 4) biphasic positive airway pressure/airway pressure release ventilation, > 60%. The inspiratory effort measured by the esophageal pressure time product increased proportionally to the amount of spontaneous breath and was accompanied by improvements in oxygenation and respiratory system elastance. Compared with biphasic positive airway pressure/airway pressure release ventilation of 0%, biphasic positive airway pressure/airway pressure release ventilation more than 60% resulted in lowest venous admixture, as well as peak and mean airway and transpulmonary pressures, redistributed ventilation to dependent lung regions, reduced the cumulative diffuse alveolar damage score across lungs (median [interquartile range], 11 [3-40] vs 18 [2-69]; p < 0.05), and decreased the level of tumor necrosis factor-α in ventral lung tissue (median [interquartile range], 17.7 pg/mg [8.4-19.8] vs 34.5 pg/mg [29.9-42.7]; p < 0.05). Biphasic positive airway pressure/airway pressure release ventilation more than 0-30% and more than 30-60% showed a less consistent pattern of improvement in lung function, inflammation, and damage compared with biphasic positive airway pressure/airway pressure release ventilation more than 60%. In this model of moderate acute respiratory distress syndrome in pigs, biphasic positive airway pressure/airway pressure release ventilation with levels of spontaneous breath higher than usually seen in clinical practice, that is, more than 30% of total minute ventilation, reduced lung injury with improved respiratory function, as compared with protective controlled mechanical ventilation.

  13. Summary of human responses to ventilation.

    PubMed

    Seppänen, O A; Fisk, W J

    2004-01-01

    It is known that ventilation is necessary to remove indoor-generated pollutants from indoor air or dilute their concentration to acceptable levels. But as the limit values of all pollutants are not known the exact determination of required ventilation rates based on pollutant concentrations is seldom possible. The selection of ventilation rates has to be based also on epidemiological research, laboratory and field experiments and experience. The existing literature indicates that ventilation has a significant impact on several important human outcomes including: (1) communicable respiratory illnesses; (2) sick building syndrome symptoms; (3) task performance and productivity, and (4) perceived air quality (PAQ) among occupants or sensory panels (5) respiratory allergies and asthma. In many studies, prevalence of sick building syndrome symptoms has also been associated with characteristics of HVAC-systems. Often the prevalence of SBS symptoms is higher in air-conditioned buildings than in naturally ventilated buildings. The evidence suggests that better hygiene, commissioning, operation and maintenance of air handling systems may be particularly important for reducing the negative effects of HVAC systems. Ventilation may also have harmful effects on indoor air quality and climate if not properly designed, installed, maintained and operated. Ventilation may bring indoors harmful substances or deteriorate indoor environment. Ventilation interacts also with the building envelope and may deteriorate the structures of the building. Ventilation changes the pressure differences across the structures of building and may cause or prevent infiltration of pollutants from structures or adjacent spaces. Ventilation is also in many cases used to control the thermal environment or humidity in buildings. The paper summarises the current knowledge on positive and negative effects of ventilation on health and other human responses. The focus is on office-type working environment and residential buildings. The review shows that ventilation has various positive impacts on health and productivity of building occupants. Ventilation reduces the prevalence of airborne infectious diseases and thus the number of sick leave days. In office environment a ventilation rate up to 20-25 L/s per person seem to decrease the prevalence of SBS-symptoms. Air conditioning systems may increase the prevalence of SBS-symptoms relative to natural ventilation if not clean. In residential buildings the air change rate in cold climates should not be below app. 0.5 ach. Ventilation systems may cause pressure differences over the building envelope and bring harmful pollutants indoors.

  14. Lung protective mechanical ventilation and two year survival in patients with acute lung injury: prospective cohort study.

    PubMed

    Needham, Dale M; Colantuoni, Elizabeth; Mendez-Tellez, Pedro A; Dinglas, Victor D; Sevransky, Jonathan E; Dennison Himmelfarb, Cheryl R; Desai, Sanjay V; Shanholtz, Carl; Brower, Roy G; Pronovost, Peter J

    2012-04-05

    To evaluate the association of volume limited and pressure limited (lung protective) mechanical ventilation with two year survival in patients with acute lung injury. Prospective cohort study. 13 intensive care units at four hospitals in Baltimore, Maryland, USA. 485 consecutive mechanically ventilated patients with acute lung injury. Two year survival after onset of acute lung injury. 485 patients contributed data for 6240 eligible ventilator settings, as measured twice daily (median of eight eligible ventilator settings per patient; 41% of which adhered to lung protective ventilation). Of these patients, 311 (64%) died within two years. After adjusting for the total duration of ventilation and other relevant covariates, each additional ventilator setting adherent to lung protective ventilation was associated with a 3% decrease in the risk of mortality over two years (hazard ratio 0.97, 95% confidence interval 0.95 to 0.99, P=0.002). Compared with no adherence, the estimated absolute risk reduction in two year mortality for a prototypical patient with 50% adherence to lung protective ventilation was 4.0% (0.8% to 7.2%, P=0.012) and with 100% adherence was 7.8% (1.6% to 14.0%, P=0.011). Lung protective mechanical ventilation was associated with a substantial long term survival benefit for patients with acute lung injury. Greater use of lung protective ventilation in routine clinical practice could reduce long term mortality in patients with acute lung injury. Clinicaltrials.gov NCT00300248.

  15. Mechanical ventilation during extracorporeal membrane oxygenation. An international survey.

    PubMed

    Marhong, Jonathan D; Telesnicki, Teagan; Munshi, Laveena; Del Sorbo, Lorenzo; Detsky, Michael; Fan, Eddy

    2014-07-01

    In patients with severe, acute respiratory failure undergoing venovenous extracorporeal membrane oxygenation (VV-ECMO), the optimal strategy for mechanical ventilation is unclear. Our objective was to describe ventilation practices used in centers registered with the Extracorporeal Life Support Organization (ELSO). We conducted an international cross-sectional survey of medical directors and ECMO program coordinators from all ELSO-registered centers. The survey was distributed using a commercial website that collected information on center characteristics, the presence of a mechanical ventilator protocol, ventilator settings, and weaning practices. E-mails were sent out to medical directors or coordinators at each ELSO center and their responses were pooled for analysis. We analyzed 141 (50%) individual responses from the 283 centers contacted across 28 countries. Only 27% of centers reported having an explicit mechanical ventilation protocol for ECMO patients. The majority of these centers (77%) reported "lung rest" to be the primary goal of mechanical ventilation, whereas 9% reported "lung recruitment" to be their ventilation strategy. A tidal volume of 6 ml/kg or less was targeted by 76% of respondents, and 58% targeted a positive end-expiratory pressure of 6-10 cm H2O while ventilating patients on VV-ECMO. Centers prioritized weaning VV-ECMO before mechanical ventilation. Although ventilation practices in patients supported by VV-ECMO vary across ELSO centers internationally, the majority of centers used a strategy that targeted lung-protective thresholds and prioritized weaning VV-ECMO over mechanical ventilation.

  16. Ventilation via Cut Nasotracheal Tube During General Anesthesia

    PubMed Central

    Asahi, Yoshinao; Omichi, Shiro; Adachi, Seita; Kagamiuchi, Hajime; Kotani, Junichiro

    2013-01-01

    Many patients with disabilities need recurrent dental treatment under general anesthesia because of high caries prevalence and the nature of dental treatment. We evaluated the use of a nasal device as a possible substitute for flexible laryngeal mask airway to reduce the risk of unexpected failure accompanying intubation; we succeeded in ventilating the lungs with a cut nasotracheal tube (CNT) with its tip placed in the pharynx. We hypothesized that this technique would be useful during dental treatment under general anesthesia and investigated its usefulness as part of a minimally invasive technique. A prospective study was designed using general anesthesia in 37 dental patients with disabilities such as intellectual impairment, autism, and cerebral palsy. CNT ventilation was compared with mask ventilation with the patient in 3 positions: the neck in flexion, horizontal position, and in extension. The effect of mouth gags was also recorded during CNT ventilation. The percentages of cases with effective ventilation were similar for the 2 techniques in the neck extension and horizontal positions (89.2–97.3%). However, CNT ventilation was significantly more effective than mask ventilation in the neck flexion position (94.6 vs 45.9%; P < .0001). Mouth gags slightly reduced the rate of effective ventilation in the neck flexion position. Most dental treatments involving minor oral surgeries were performed using mouth gags during CNT ventilation. CNT ventilation was shown to be superior to mask ventilation and is useful during dental treatment under general anesthesia. PMID:23506278

  17. Daytime Mouthpiece for Continuous Noninvasive Ventilation in Individuals With Amyotrophic Lateral Sclerosis.

    PubMed

    Bédard, Marie-Eve; McKim, Douglas A

    2016-10-01

    Noninvasive ventilation (NIV) is commonly used to provide ventilatory support for individuals with amyotrophic lateral sclerosis (ALS). Once 24-h ventilation is required, the decision between invasive tracheostomy ventilation and palliation is often faced. This study describes the use and outcomes of daytime mouthpiece ventilation added to nighttime mask ventilation for continuous NIV in subjects with ALS as an effective alternative. This was a retrospective study of 39 subjects with ALS using daytime mouthpiece ventilation over a 17-y period. Thirty-one subjects were successful with mouthpiece ventilation, 2 were excluded, 2 stopped because of lack of motivation, and 4 with bulbar subscores of the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (b-ALSFRS-R) between 0 and 3 physically failed to use it consistently. No subject in the successful group had a b-ALSFRS-R score of <6. Thirty of the successful subjects were able to generate a maximum insufflation capacity - vital capacity difference with lung volume recruitment. The median (range) survival to tracheostomy or death from initiation of nocturnal NIV and mouthpiece ventilation were 648 (176-2,188) and 286 (41-1,769) d, respectively. Peak cough flow with lung-volume recruitment >180 L/min at initiation of mouthpiece ventilation was associated with a longer survival (637 ± 468 vs 240 ± 158 d (P = .01). Mouthpiece ventilation provides effective ventilation and prolonged survival for individuals with ALS requiring full-time ventilatory support and maintaining adequate bulbar function. Copyright © 2016 by Daedalus Enterprises.

  18. [Lung protective ventilation. Ventilatory modes and ventilator parameters].

    PubMed

    Schädler, Dirk; Weiler, Norbert

    2008-06-01

    Mechanical ventilation has a considerable potential for injuring the lung tissue. Therefore, attention has to be paid to the proper choice of ventilatory mode and settings to secure lung-protective ventilation whenever possible. Such ventilator strategy should account for low tidal volume ventilation (6 ml/kg PBW), limited plateau pressure (30 to 35 cm H2O) and positive end-expiratory pressure (PEEP). It is unclear whether pressure controlled or volume controlled ventilation with square flow profile is beneficial. The adjustment of inspiration and expiration time should consider the actual breathing mechanics and anticipate the generation of intrinsic PEEP. Ventilatory modes with the possibility of supporting spontaneous breathing should be used as soon as possible.

  19. Noise measurements during high-frequency oscillatory and conventional mechanical ventilation.

    PubMed

    Berens, R J; Weigle, C G

    1995-10-01

    To evaluate the noise levels with high-frequency oscillatory ventilation and conventional mechanical ventilation. An observational, prospective study. Pediatric intensive care unit. The caretakers and environment of the pediatric intensive care unit. High-frequency oscillatory and conventional mechanical ventilation. Caretakers evaluated noise using a visual analog scale. Noise was measured with a decibel meter and an octave band frequency filter. There was twice as much noise perceived by the caretakers and as measured on the decibel A scale. All measures showed significantly greater noise, especially at low frequencies, with high-frequency oscillatory ventilation. High-frequency oscillatory ventilation exposes the patient to twice as much noise as does the use of conventional mechanical ventilation.

  20. High-Frequency Percussive Ventilation Revisited

    DTIC Science & Technology

    2010-01-01

    be implemented. ‡ Follow the reverse of the ventilation sequence if respiratory alkalosis develops—however, start at ventilation goal sequence 1 not at...High-frequency percussive ventilation (HFPV) has demonstrated a potential role as a rescue option for refractory acute respiratory distress syndrome...frequency percussive ventilation (HFPV) has demon- strated a potential role as a salvage option for refrac- tory acute respiratory distress syndrome

  1. Development of an Outdoor Temperature-Based Control Algorithm for Residential Mechanical Ventilation Control

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Less, Brennan; Walker, Iain; Tang, Yihuan

    2014-06-01

    Smart ventilation systems use controls to ventilate more during those periods that provide either an energy or IAQ advantage (or both) and less during periods that provide a dis advantage. Using detailed building simulations, this study addresses one of the simplest and lowest cost types of smart controllers —outdoor temperature- based control. If the outdoor temperature falls below a certain cut- off, the fan is simply turned off. T he main principle of smart ventilation used in this study is to shift ventilation from time periods with large indoor -outdoor temperature differences, to periods where these differences are smaller, andmore » their energy impacts are expected to be less. Energy and IAQ performance are assessed relative to a base case of a continuously operated ventilation fan sized to comply with ASHRAE 62.2-2013 whole house ventilation requirements. In order to satisfy 62.2-2013, annual pollutant exposure must be equivalent between the temperature controlled and continuous fan cases. This requires ventilation to be greater than 62.2 requirements when the ventilation system operates. This is achieved by increasing the mechanical ventilation system air flow rates.« less

  2. Performance of ICU ventilators during noninvasive ventilation with large leaks in a total face mask: a bench study.

    PubMed

    Nakamura, Maria Aparecida Miyuki; Costa, Eduardo Leite Vieira; Carvalho, Carlos Roberto Ribeiro; Tucci, Mauro Roberto

    2014-01-01

    Discomfort and noncompliance with noninvasive ventilation (NIV) interfaces are obstacles to NIV success. Total face masks (TFMs) are considered to be a very comfortable NIV interface. However, due to their large internal volume and consequent increased CO2 rebreathing, their orifices allow proximal leaks to enhance CO2 elimination. The ventilators used in the ICU might not adequately compensate for such leakage. In this study, we attempted to determine whether ICU ventilators in NIV mode are suitable for use with a leaky TFM. This was a bench study carried out in a university research laboratory. Eight ICU ventilators equipped with NIV mode and one NIV ventilator were connected to a TFM with major leaks. All were tested at two positive end-expiratory pressure (PEEP) levels and three pressure support levels. The variables analyzed were ventilation trigger, cycling off, total leak, and pressurization. Of the eight ICU ventilators tested, four did not work (autotriggering or inappropriate turning off due to misdetection of disconnection); three worked with some problems (low PEEP or high cycling delay); and one worked properly. The majority of the ICU ventilators tested were not suitable for NIV with a leaky TFM.

  3. A complete audit cycle to assess adherence to a lung protective ventilation strategy.

    PubMed

    Joynes, Emma; Dalay, Satinder; Patel, Jaimin M; Fayek, Samia

    2014-11-01

    There is clear evidence for the use of a protective ventilation protocol in patients with acute respiratory distress syndrome (ARDS). There is evidence to suggest that protective ventilation is beneficial in patients at risk of ARDS. A protective ventilation strategy was implemented on our intensive care unit in critical care patients who required mechanical ventilation for over 48 h, with and at risk for ARDS. A complete audit cycle was performed over 13 months to assess compliance with a safe ventilation protocol in intensive care. The ARDS network mechanical ventilation protocol was used as the standard for our protective ventilation strategy. This recommends ventilation with a tidal volume (V t) of 6 ml/kg of ideal body weight (IBW) and plateau airway pressure of ≤30 cm H2O. The initial audit failed to meet this standard with V t's of 9.5 ml/kg of IBW. Following the implementation of a ventilation strategy and an educational program, we demonstrate a significant improvement in practice with V t's of 6.6 ml/kg of IBW in the re-audit. This highlights the importance of simple interventions and continuous education in maintaining high standards of care.

  4. Variable tidal volumes improve lung protective ventilation strategies in experimental lung injury.

    PubMed

    Spieth, Peter M; Carvalho, Alysson R; Pelosi, Paolo; Hoehn, Catharina; Meissner, Christoph; Kasper, Michael; Hübler, Matthias; von Neindorff, Matthias; Dassow, Constanze; Barrenschee, Martina; Uhlig, Stefan; Koch, Thea; de Abreu, Marcelo Gama

    2009-04-15

    Noisy ventilation with variable Vt may improve respiratory function in acute lung injury. To determine the impact of noisy ventilation on respiratory function and its biological effects on lung parenchyma compared with conventional protective mechanical ventilation strategies. In a porcine surfactant depletion model of lung injury, we randomly combined noisy ventilation with the ARDS Network protocol or the open lung approach (n = 9 per group). Respiratory mechanics, gas exchange, and distribution of pulmonary blood flow were measured at intervals over a 6-hour period. Postmortem, lung tissue was analyzed to determine histological damage, mechanical stress, and inflammation. We found that, at comparable minute ventilation, noisy ventilation (1) improved arterial oxygenation and reduced mean inspiratory peak airway pressure and elastance of the respiratory system compared with the ARDS Network protocol and the open lung approach, (2) redistributed pulmonary blood flow to caudal zones compared with the ARDS Network protocol and to peripheral ones compared with the open lung approach, (3) reduced histological damage in comparison to both protective ventilation strategies, and (4) did not increase lung inflammation or mechanical stress. Noisy ventilation with variable Vt and fixed respiratory frequency improves respiratory function and reduces histological damage compared with standard protective ventilation strategies.

  5. Adherence to the items in a bundle for the prevention of ventilator-associated pneumonia.

    PubMed

    Sachetti, Amanda; Rech, Viviane; Dias, Alexandre Simões; Fontana, Caroline; Barbosa, Gilberto da Luz; Schlichting, Dionara

    2014-01-01

    To assess adherence to a ventilator care bundle in an intensive care unit and to determine the impact of adherence on the rates of ventilator-associated pneumonia. A total of 198 beds were assessed for 60 days using a checklist that consisted of the following items: bed head elevation to 30 to 45º; position of the humidifier filter; lack of fluid in the ventilator circuit; oral hygiene; cuff pressure; and physical therapy. Next, an educational lecture was delivered, and 235 beds were assessed for the following 60 days. Data were also collected on the incidence of ventilator-acquired pneumonia. Adherence to the following ventilator care bundle items increased: bed head elevation from 18.7% to 34.5%; lack of fluid in the ventilator circuit from 55.6% to 72.8%; oral hygiene from 48.5% to 77.8%; and cuff pressure from 29.8% to 51.5%. The incidence of ventilator-associated pneumonia was statistically similar before and after intervention (p=0.389). The educational intervention performed in this study increased the adherence to the ventilator care bundle, but the incidence of ventilator-associated pneumonia did not decrease in the small sample that was assessed.

  6. Assessment of ventilation and indoor air pollutants in nursery and elementary schools in France.

    PubMed

    Canha, N; Mandin, C; Ramalho, O; Wyart, G; Ribéron, J; Dassonville, C; Hänninen, O; Almeida, S M; Derbez, M

    2016-06-01

    The aim of this study was to characterize the relationship between Indoor Air Quality (IAQ) and ventilation in French classrooms. Various parameters were measured over one school week, including volatile organic compounds, aldehydes, particulate matter (PM2.5 mass concentration and number concentration), carbon dioxide (CO2 ), air temperature, and relative humidity in 51 classrooms at 17 schools. The ventilation was characterized by several indicators, such as the air exchange rate, ventilation rate (VR), and air stuffiness index (ICONE), that are linked to indoor CO2 concentration. The influences of the season (heating or non-heating), type of school (nursery or elementary), and ventilation on the IAQ were studied. Based on the minimum value of 4.2 l/s per person required by the French legislation for mechanically ventilated classrooms, 91% of the classrooms had insufficient ventilation. The VR was significantly higher in mechanically ventilated classrooms compared with naturally ventilated rooms. The correlations between IAQ and ventilation vary according to the location of the primary source of each pollutant (outdoor vs. indoor), and for an indoor source, whether it is associated with occupant activity or continuous emission. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  7. Implementation of a Goal-Directed Mechanical Ventilation Order Set Driven by Respiratory Therapists Improves Compliance With Best Practices for Mechanical Ventilation.

    PubMed

    Radosevich, Misty A; Wanta, Brendan T; Meyer, Todd J; Weber, Verlin W; Brown, Daniel R; Smischney, Nathan J; Diedrich, Daniel A

    2017-01-01

    Data regarding best practices for ventilator management strategies that improve outcomes in acute respiratory distress syndrome (ARDS) are readily available. However, little is known regarding processes to ensure compliance with these strategies. We developed a goal-directed mechanical ventilation order set that included physician-specified lung-protective ventilation and oxygenation goals to be implemented by respiratory therapists (RTs). We sought as a primary outcome to determine whether an RT-driven order set with predefined oxygenation and ventilation goals could be implemented and associated with improved adherence with best practice. We evaluated 1302 patients undergoing invasive mechanical ventilation (1693 separate episodes of invasive mechanical ventilation) prior to and after institution of a standardized, goal-directed mechanical ventilation order set using a controlled before-and-after study design. Patient-specific goals for oxygenation partial pressure of oxygen in arterial blood (Pao 2 ), ARDS Network [Net] positive end-expiratory pressure [PEEP]/fraction of inspired oxygen [Fio 2 ] table use) and ventilation (pH, partial pressure of carbon dioxide) were selected by prescribers and implemented by RTs. Compliance with the new mechanical ventilation order set was high: 88.2% compliance versus 3.8% before implementation of the order set ( P < .001). Adherence to the PEEP/Fio 2 table after implementation of the order set was significantly greater (86.0% after vs 82.9% before, P = .02). There was no difference in duration of mechanical ventilation, intensive care unit (ICU) length of stay, and in-hospital or ICU mortality. A standardized best practice mechanical ventilation order set can be implemented by a multidisciplinary team and is associated with improved compliance to written orders and adherence to the ARDSNet PEEP/Fio 2 table.

  8. Transtracheal ventilation with a novel ejector-based device (Ventrain) in open, partly obstructed, or totally closed upper airways in pigs.

    PubMed

    Paxian, M; Preussler, N P; Reinz, T; Schlueter, A; Gottschall, R

    2015-08-01

    Transtracheal access and subsequent jet ventilation are among the last options in a 'cannot intubate-cannot oxygenate' scenario. These interventions may lead to hypercapnia, barotrauma, and haemodynamic failure in the event of an obstructed upper airway. The aim of the present study was to evaluate the efficacy and the haemodynamic effects of the Ventrain, a manually operated ventilation device that provides expiratory ventilation assistance. Transtracheal ventilation was carried out with the Ventrain in different airway scenarios in live pigs, and its performance was compared with a conventional jet ventilator. Pigs with open, partly obstructed, or completely closed upper airways were transtracheally ventilated either with the Ventrain or by conventional jet ventilation. Airway pressures, haemodynamic parameters, and blood gases obtained in the different settings were compared. Mean (SD) alveolar minute ventilation as reflected by arterial partial pressure of CO2 was superior with the Ventrain in partly obstructed airways after 6 min in comparison with traditional manual jet ventilation [4.7 (0.19) compared with 7.1 (0.37) kPa], and this was also the case in all simulated airway conditions. At the same time, peak airway pressures were significantly lower and haemodynamic parameters were altered to a lesser extent with the Ventrain. The results of this study suggest that the Ventrain device can ensure sufficient oxygenation and ventilation through a small-bore transtracheal catheter when the airway is open, partly obstructed, or completely closed. Minute ventilation and avoidance of high airway pressures were superior in comparison with traditional hand-triggered jet ventilation, particularly in the event of complete upper airway obstruction. © The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. The performances of standard and ResMed masks during bag-valve-mask ventilation.

    PubMed

    Lee, Hyoung Youn; Jeung, Kyung Woon; Lee, Byung Kook; Lee, Seung Joon; Jung, Yong Hun; Lee, Geo Sung; Min, Yong Il; Heo, Tag

    2013-01-01

    A tight mask seal is frequently difficult to obtain and maintain during single-rescuer bag-valve-mask (BVM) ventilation. The ResMed mask (Bella Vista, NSW, Australia) is a continuous-positive-airway-pressure mask (CM) designed for noninvasive ventilation. In this study, we compared the ventilation performances of a standard mask (SM) and a ResMed CM using a simulation manikin in an out-of-hospital single-rescuer BVM ventilation scenario. Thirty emergency medical technicians (EMTs) performed two 2-minute attempts to ventilate a simulation manikin using BVM ventilation, alternatively, with the SM or the ResMed CM in a randomized order. Ventilation parameters including tidal volume and peak airway pressure were measured using computer analysis software connected to the simulation manikin. Successful volume delivery was defined as delivery of 440-540 mL of tidal volume in accord with present cardiopulmonary resuscitation guidelines. BVM ventilation using the ResMed CM produced higher mean (± standard deviation) tidal volumes (452 ± 50 mL vs. 394 ± 113 mL, p = 0.014) and had a higher proportion of successful volume deliveries (65.3% vs. 26.7%, p < 0.001) than that using the SM. Peak airway pressure was higher in BVM ventilation using the ResMed CM (p = 0.035). Stomach insufflation did not occur during either method. Twenty-nine of the participants (96.7%) preferred BVM ventilation using the ResMed CM. BVM ventilations using ResMed CM resulted in a significantly higher proportion of successful volume deliveries meeting the currently recommended range of tidal volume. Clinical studies are needed to determine the value of the ResMed CM for BVM ventilation.

  10. Nasal mask ventilation is better than face mask ventilation in edentulous patients

    PubMed Central

    Kapoor, Mukul Chandra; Rana, Sandeep; Singh, Arvind Kumar; Vishal, Vindhya; Sikdar, Indranil

    2016-01-01

    Background and Aims: Face mask ventilation of the edentulous patient is often difficult as ineffective seating of the standard mask to the face prevents attainment of an adequate air seal. The efficacy of nasal ventilation in edentulous patients has been cited in case reports but has never been investigated. Material and Methods: Consecutive edentulous adult patients scheduled for surgery under general anesthesia with endotracheal intubation, during a 17-month period, were prospectively evaluated. After induction of anesthesia and administration of neuromuscular blocker, lungs were ventilated with a standard anatomical face mask of appropriate size, using a volume controlled anesthesia ventilator with tidal volume set at 10 ml/kg. In case of inadequate ventilation, the mask position was adjusted to achieve best-fit. Inspired and expired tidal volumes were measured. Thereafter, the face mask was replaced by a nasal mask and after achieving best-fit, the inspired and expired tidal volumes were recorded. The difference in expired tidal volumes and airway pressures at best-fit with the use of the two masks and number of patients with inadequate ventilation with use of the masks were statistically analyzed. Results: A total of 79 edentulous patients were recruited for the study. The difference in expiratory tidal volumes with the use of the two masks at best-fit was statistically significant (P = 0.0017). Despite the best-fit mask placement, adequacy of ventilation could not be achieved in 24.1% patients during face mask ventilation, and 12.7% patients during nasal mask ventilation and the difference was statistically significant. Conclusion: Nasal mask ventilation is more efficient than standard face mask ventilation in edentulous patients. PMID:27625477

  11. Automatic control of pressure support for ventilator weaning in surgical intensive care patients.

    PubMed

    Schädler, Dirk; Engel, Christoph; Elke, Gunnar; Pulletz, Sven; Haake, Nils; Frerichs, Inéz; Zick, Günther; Scholz, Jens; Weiler, Norbert

    2012-03-15

    Despite its ability to reduce overall ventilation time, protocol-guided weaning from mechanical ventilation is not routinely used in daily clinical practice. Clinical implementation of weaning protocols could be facilitated by integration of knowledge-based, closed-loop controlled protocols into respirators. To determine whether automated weaning decreases overall ventilation time compared with weaning based on a standardized written protocol in an unselected surgical patient population. In this prospective controlled trial patients ventilated for longer than 9 hours were randomly allocated to receive either weaning with automatic control of pressure support ventilation (automated-weaning group) or weaning based on a standardized written protocol (control group) using the same ventilation mode. The primary end point of the study was overall ventilation time. Overall ventilation time (median [25th and 75th percentile]) did not significantly differ between the automated-weaning (31 [19-101] h; n = 150) and control groups (39 [20-118] h; n = 150; P = 0.178). Patients who underwent cardiac surgery (n = 132) exhibited significantly shorter overall ventilation times in the automated-weaning (24 [18-57] h) than in the control group (35 [20-93] h; P = 0.035). The automated-weaning group exhibited shorter ventilation times until the first spontaneous breathing trial (1 [0-15] vs. 9 [1-51] h; P = 0.001) and a trend toward fewer tracheostomies (17 vs. 28; P = 0.075). Overall ventilation times did not significantly differ between weaning using automatic control of pressure support ventilation and weaning based on a standardized written protocol. Patients after cardiac surgery may benefit from automated weaning. Implementation of additional control variables besides the level of pressure support may further improve automated-weaning systems. Clinical trial registered with www.clinicaltrials.gov (NCT 00445289).

  12. The use of chilled condensers for the recovery of perfluorocarbon liquid in an experimental model of perfluorocarbon vapour loss during neonatal partial liquid ventilation

    PubMed Central

    Dunster, Kimble R; Davies, Mark W; Fraser, John F

    2007-01-01

    Background Perfluorocarbon (PFC) vapour in the expired gases during partial liquid ventilation should be prevented from entering the atmosphere and recovered for potential reuse. This study aimed to determine how much PFC liquid could be recovered using a conventional humidified neonatal ventilator with chilled condensers in place of the usual expiratory ventilator circuit and whether PFC liquid could be recovered when using the chilled condensers at the ventilator exhaust outlet. Methods Using a model lung, perfluorocarbon vapour loss during humidified partial liquid ventilation of a 3.5 kg infant was approximated. For each test 30 mL of FC-77 was infused into the model lung. Condensers were placed in the expiratory limb of the ventilator circuit and the amounts of PFC (FC-77) and water recovered were measured five times. This was repeated with the condensers placed at the ventilator exhaust outlet. Results When the condensers were used as the expiratory limb, the mean (± SD) volume of FC77 recovered was 16.4 mL (± 0.18 mL). When the condensers were connected to the ventilator exhaust outlet the mean (± SD) volume of FC-77 recovered was 7.6 mL (± 1.14 mL). The volume of FC-77 recovered was significantly higher when the condenser was used as an expiratory limb. Conclusion Using two series connected condensers in the ventilator expiratory line 55% of PFC liquid (FC-77) can be recovered during partial liquid ventilation without altering the function of the of the ventilator circuit. This volume of PFC recovered was just over twice that recovered with the condensers connected to the ventilator exhaust outlet. PMID:17537270

  13. Quantitative analysis of hyperpolarized 129Xe ventilation imaging in healthy volunteers and subjects with chronic obstructive pulmonary disease

    PubMed Central

    Virgincar, Rohan S.; Cleveland, Zackary I.; Kaushik, S. Sivaram; Freeman, Matthew S.; Nouls, John; Cofer, Gary P.; Martinez-Jimenez, Santiago; He, Mu; Kraft, Monica; Wolber, Jan; McAdams, H. Page; Driehuys, Bastiaan

    2013-01-01

    In this study, hyperpolarized (HP) 129Xe MR ventilation and 1H anatomical images were obtained from 3 subject groups: young healthy volunteers (HV), subjects with chronic obstructive pulmonary disease (COPD), and age-matched control subjects (AMC). Ventilation images were quantified by 2 methods: an expert reader-based ventilation defect score percentage (VDS%) and a semi-automatic segmentation-based ventilation defect percentage (VDP). Reader-based values were assigned by two experienced radiologists and resolved by consensus. In the semi-automatic analysis, 1H anatomical images and 129Xe ventilation images were both segmented following registration, to obtain the thoracic cavity volume (TCV) and ventilated volume (VV), respectively, which were then expressed as a ratio to obtain the VDP. Ventilation images were also characterized by generating signal intensity histograms from voxels within the TCV, and heterogeneity was analyzed using the coefficient of variation (CV). The reader-based VDS% correlated strongly with the semi-automatically generated VDP (r = 0.97, p < 0.0001), and with CV (r = 0.82, p < 0.0001). Both 129Xe ventilation defect scoring metrics readily separated the 3 groups from one another and correlated significantly with FEV1 (VDS%: r = -0.78, p = 0.0002; VDP: r = -0.79, p = 0.0003; CV: r = -0.66, p = 0.0059) and other pulmonary function tests. In the healthy subject groups (HV and AMC), the prevalence of ventilation defects also increased with age (VDS%: r = 0.61, p = 0.0002; VDP: r = 0.63, p = 0.0002). Moreover, ventilation histograms and their associated CVs distinguished between COPD subjects with similar ventilation defect scores but visibly different ventilation patterns. PMID:23065808

  14. A Case-Control Study on the Impact of Ventilator-Associated Tracheobronchitis in the PICU.

    PubMed

    Wheeler, Derek S; Whitt, John D; Lake, Michael; Butcher, John; Schulte, Marion; Stalets, Erika

    2015-07-01

    Hospital-acquired infections increase morbidity, mortality, and charges in the PICU. We implemented a quality improvement bundle directed at ventilator-associated pneumonia in our PICU in 2005. We observed an increase in ventilator-associated tracheobronchitis coincident with the near-elimination of ventilator-associated pneumonia. The impact of ventilator-associated tracheobronchitis on critically ill children has not been previously described. Accordingly, we hypothesized that ventilator-associated tracheobronchitisis associated with increased length of stay, mortality, and hospital charge. Retrospective case-control study. Critically ill children admitted to a quaternary PICU at a free-standing academic children's hospital in the United States. None. We conducted a retrospective case control study, with institutional review board approval, of 77 consecutive cases of ventilator-associated tracheobronchitis admitted to our PICU from 2004-2010. We matched each case with a control based on the following criteria (in rank order): age range (< 30 d, 30 d to 24 mo, 24 mo to 12 yr, > 12 yr), admission Pediatric Risk of Mortality III score ± 10, number of ventilator days of control group (> 75% of days until development of ventilator-associated tracheobronchitis), primary diagnosis, underlying organ system dysfunction, surgical procedure, and gender. The primary outcome measured was PICU length of stay. Secondary outcomes included ventilator days, hospital length of stay, mortality, and PICU and hospital charges. Data was analyzed using chi square analysis and p less than 0.05 was considered significant. We successfully matched 45 of 77 ventilator-associated tracheobronchitis patients with controls. There were no significant differences in age, gender, diagnosis, or Pediatric Risk of Mortality III score between groups. Ventilator-associated tracheobronchitis patients had a longer PICU length of stay (median, 21.5 d, interquartile range, 24 d) compared to controls (median, 18 d; interquartile range, 17 d), although not statistically significant (p = 0.13). Ventilator days were also longer in the ventilator-associated tracheobronchitis patients (median, 17 d; IQR, 22 d) versus control (median, 10.5 d; interquartile range, 13 d) (p = 0.01). There was no significant difference in total hospital length of stay (54 d vs 36 d; p = 0.69). PICU mortality was higher in the ventilator-associated tracheobronchitis group (15% vs 5%; p = 0.14), although not statistically significant. There was an increase in both median PICU charges ($197,393 vs $172,344; p < 0.05) and hospital charges ($421,576 vs $350,649; p < 0.05) for ventilator-associated tracheobronchitis patients compared with controls. Ventilator-associated tracheobronchitis is a clinically significant hospital-acquired infection in the PICU and is associated with longer duration of mechanical ventilation and healthcare costs, possibly through causing a longer PICU length of stay. Quality improvement efforts should be directed at reducing the incidence of ventilator-associated tracheobronchitis in the PICU.

  15. Insights into Ventilatory Inhomogeneity from Respiratory Measurements on Spacelab Mission D-2

    NASA Technical Reports Server (NTRS)

    Paiva, Manuel; Verbanck, Sylvia; Linnarsson, Dag; Prisk, Kim; West, John B.

    1996-01-01

    The relative contributions of inter-regional and intra-regional ventilation inhomogeneities of Spacelab astronauts are studied. The classical theory of ventilation distribution in the lung is that the top-to-bottom (inter-regional) ventilation inhomogeneities are primarily gravity dependent, whereas the peripheral (intra-regional) ventilation distribution is gravity independent. Argon rebreathing tests showed that gravity independent specific ventilation (ventilation per unit volume) inhomogeneities are at least as large as gravity dependent ones. Single breath tests with helium and sulfur hexafluoride showed the different sensitivity of these gases to microgravity.

  16. Subglottic secretion drainage for the prevention of ventilator-associated pneumonia: a systematic review and meta-analysis.

    PubMed

    Muscedere, John; Rewa, Oleksa; McKechnie, Kyle; Jiang, Xuran; Laporta, Denny; Heyland, Daren K

    2011-08-01

    Aspiration of secretions containing bacterial pathogens into the lower respiratory tract is the main cause of ventilator-associated pneumonia. Endotracheal tubes with subglottic secretion drainage can potentially reduce this and, therefore, the incidence of ventilator-associated pneumonia. New evidence on subglottic secretion drainage as a preventive measure for ventilator-associated pneumonia has been recently published and to consider the evidence in totality, we conducted an updated systematic review and meta-analysis. We searched computerized databases, reference lists, and personal files. We included randomized clinical trials of mechanically ventilated patients comparing standard endotracheal tubes to those with subglottic secretion drainage and reporting on the occurrence of ventilator-associated pneumonia. Studies were meta-analyzed for the primary outcome of ventilator-associated pneumonia and secondary clinical outcomes. We identified 13 randomized clinical trials that met the inclusion criteria with a total of 2442 randomized patients. Of the 13 studies, 12 reported a reduction in ventilator-associated pneumonia rates in the subglottic secretion drainage arm; in meta-analysis, the overall risk ratio for ventilator-associated pneumonia was 0.55 (95% confidence interval, 0.46-0.66; p < .00001) with no heterogeneity (I = 0%). The use of subglottic secretion drainage was associated with reduced intensive care unit length of stay (-1.52 days; 95% confidence interval, -2.94 to -0.11; p = .03); decreased duration of mechanically ventilated (-1.08 days; 95% confidence interval, -2.04 to -0.12; p = .03), and increased time to first episode of ventilator-associated pneumonia (2.66 days; 95% confidence interval, 1.06-4.26; p = .001). There was no effect on adverse events or on hospital or intensive care unit mortality. In those at risk for ventilator-associated pneumonia, the use of endotracheal tubes with subglottic secretion drainage is effective for the prevention of ventilator-associated pneumonia and may be associated with reduced duration of mechanical ventilation and intensive care unit length of stay.

  17. Influences of Duration of Inspiratory Effort, Respiratory Mechanics, and Ventilator Type on Asynchrony With Pressure Support and Proportional Assist Ventilation.

    PubMed

    Vasconcelos, Renata S; Sales, Raquel P; Melo, Luíz H de P; Marinho, Liégina S; Bastos, Vasco Pd; Nogueira, Andréa da Nc; Ferreira, Juliana C; Holanda, Marcelo A

    2017-05-01

    Pressure support ventilation (PSV) is often associated with patient-ventilator asynchrony. Proportional assist ventilation (PAV) offers inspiratory assistance proportional to patient effort, minimizing patient-ventilator asynchrony. The objective of this study was to evaluate the influence of respiratory mechanics and patient effort on patient-ventilator asynchrony during PSV and PAV plus (PAV+). We used a mechanical lung simulator and studied 3 respiratory mechanics profiles (normal, obstructive, and restrictive), with variations in the duration of inspiratory effort: 0.5, 1.0, 1.5, and 2.0 s. The Auto-Trak system was studied in ventilators when available. Outcome measures included inspiratory trigger delay, expiratory trigger asynchrony, and tidal volume (V T ). Inspiratory trigger delay was greater in the obstructive respiratory mechanics profile and greatest with a effort of 2.0 s (160 ms); cycling asynchrony, particularly delayed cycling, was common in the obstructive profile, whereas the restrictive profile was associated with premature cycling. In comparison with PSV, PAV+ improved patient-ventilator synchrony, with a shorter triggering delay (28 ms vs 116 ms) and no cycling asynchrony in the restrictive profile. V T was lower with PAV+ than with PSV (630 mL vs 837 mL), as it was with the single-limb circuit ventilator (570 mL vs 837 mL). PAV+ mode was associated with longer cycling delays than were the other ventilation modes, especially for the obstructive profile and higher effort values. Auto-Trak eliminated automatic triggering. Mechanical ventilation asynchrony was influenced by effort, respiratory mechanics, ventilator type, and ventilation mode. In PSV mode, delayed cycling was associated with shorter effort in obstructive respiratory mechanics profiles, whereas premature cycling was more common with longer effort and a restrictive profile. PAV+ prevented premature cycling but not delayed cycling, especially in obstructive respiratory mechanics profiles, and it was associated with a lower V T . Copyright © 2017 by Daedalus Enterprises.

  18. Mobile communication devices causing interference in invasive and noninvasive ventilators.

    PubMed

    Dang, Bao P; Nel, Pierre R; Gjevre, John A

    2007-06-01

    The aim of this study was to assess if common mobile communication systems would cause significant interference on mechanical ventilation devices and at what distances would such interference occur. We tested all the invasive and noninvasive ventilatory devices used within our region. This consisted of 2 adult mechanical ventilators, 1 portable ventilator, 2 pediatric ventilators, and 2 noninvasive positive pressure ventilatory devices. We operated the mobile devices from the 2 cellular communication systems (digital) and 1 2-way radio system used in our province at varying distances from the ventilators and looked at any interference they created. We tested the 2-way radio system, which had a fixed operation power output of 3.0 watts, the Global Systems for Mobile Communication cellular system, which had a maximum power output of 2.0 watts and the Time Division Multiple Access cellular system, which had a maximum power output of 0.2 watts on our ventilators. The ventilators were ventilating a plastic lung at fixed settings. The mobile communication devices were tested at varying distances starting at zero meter from the ventilator and in all operation modes. The 2-way radio caused the most interference on some of the ventilators, but the maximum distance of interference was 1.0 m. The Global Systems for Mobile Communication system caused significant interference only at 0 m and minor interference at 0.5 m on only 1 ventilator. The Time Division Multiple Access system caused no interference at all. Significant interference consisted of a dramatic rise and fluctuation of the respiratory rate, pressure, and positive end-expiratory pressure of the ventilators with no normalization when the mobile device was removed. From our experiment on our ventilators with the communication systems used in our province, we conclude that mobile communication devices such as cellular phones and 2-way radios are safe and cause no interference unless operated at very close distances of less than 1 meter.

  19. Occupant Interactions and Effectiveness of Natural Ventilation Strategies in Contemporary New Housing in Scotland, UK.

    PubMed

    Sharpe, Tim; Farren, Paul; Howieson, Stirling; Tuohy, Paul; McQuillan, Jonathan

    2015-07-21

    The need to reduce carbon emissions and fuel poverty has led to increased building envelope air tightness, intended to reduce uncontrolled ventilation heat losses. Ventilation strategies in dwellings still allow the use of trickle ventilators in window frames for background ventilation. The extent to which this results in "healthy" Indoor Air Quality (IAQ) in recently constructed dwellings was a concern of regulators in Scotland. This paper describes research to explore this. First a review of literature was conducted, then data on occupant interactions with ventilation provisions (windows, doors, trickle vents) gathered through an interview-based survey of 200 recently constructed dwellings, and measurements made on a sample of 40 of these. The main measured parameter discussed here is CO2 concentration. It was concluded after the literature review that 1000 ppm absolute was a reasonable threshold to use for "adequate" ventilation. The occupant survey found that there was very little occupant interaction with the trickle ventilators e.g., in bedrooms 63% were always closed, 28% always open, and in only 9% of cases occupants intervened to make occasional adjustments. In the measured dwellings average bedroom CO2 levels of 1520 ppm during occupied (night time) hours were observed. Where windows were open the average bedroom CO2 levels were 972 ppm. With windows closed, the combination of "trickle ventilators open plus doors open" gave an average of 1021 ppm. "Trickle ventilators open" gave an average of 1571 ppm. All other combinations gave averages of 1550 to 2000 ppm. Ventilation rates and air change rates were estimated from measured CO2 levels, for all dwellings calculated ventilation rate was less than 8 L/s/p, in 42% of cases calculated air change rate was less than 0.5 ach. It was concluded that trickle ventilation as installed and used is ineffective in meeting desired ventilation rates, evidenced by high CO2 levels reported across the sampled dwellings. Potential implications of the results are discussed.

  20. WE-AB-202-06: Correlating Lung CT HU with Transformation-Based and Xe-CT Derived Ventilation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Du, K; Patton, T; Bayouth, J

    Purpose: Regional lung ventilation is useful to reduce radiation-induced function damage during lung cancer radiation therapy. Recently a new direct HU (Hounsfield unit)-based method was proposed to estimate the ventilation potential without image registration. The purpose of this study is to examine if there is a functional dependence between HU values and transformation-based or Xe-CT derived ventilation. Methods: 4DCT images acquired from 13 patients prior to radiation therapy and 4 mechanically ventilated sheep subjects which also have associated Xe-CT images were used for this analysis. Transformation-based ventilation was computed using Jacobian determinant of the transformation field between peak-exhale and peak-inhalemore » 4DCT images. Both transformation and Xe-CT derived ventilation was computed for each HU bin. Color scatter plot and cumulative histogram were used to compare and validate the direct HU-based method. Results: There was little change of the center and shape of the HU histograms between free breathing CT and 4DCT average, with or without smoothing, and between the repeated 4DCT scans. HU of −750 and −630 were found to have the greatest transformation-based ventilation for human and sheep subjects, respectively. Maximum Xe-CT derived ventilation was found to locate at HU of −600 in sheep subjects. The curve between Xe-CT ventilation and HU was noisy for tissue above HU −400, possibly due to less intensity change of Xe gas during wash-out and wash-in phases. Conclusion: Both transformation-based and Xe-CT ventilation demonstrated that lung tissues with HU values in the range of (-750, −600) HU have the maximum ventilation potential. The correlation between HU and ventilation suggests that HU might be used to help guide the ventilation calculation and make it more robust to noise and image registration errors. Research support from NIH grants CA166703 and CA166119 and a gift from Roger Koch.« less

  1. Investigation of four-dimensional computed tomography-based pulmonary ventilation imaging in patients with emphysematous lung regions

    NASA Astrophysics Data System (ADS)

    Yamamoto, Tokihiro; Kabus, Sven; Klinder, Tobias; Lorenz, Cristian; von Berg, Jens; Blaffert, Thomas; Loo, Billy W., Jr.; Keall, Paul J.

    2011-04-01

    A pulmonary ventilation imaging technique based on four-dimensional (4D) computed tomography (CT) has advantages over existing techniques. However, physiologically accurate 4D-CT ventilation imaging has not been achieved in patients. The purpose of this study was to evaluate 4D-CT ventilation imaging by correlating ventilation with emphysema. Emphysematous lung regions are less ventilated and can be used as surrogates for low ventilation. We tested the hypothesis: 4D-CT ventilation in emphysematous lung regions is significantly lower than in non-emphysematous regions. Four-dimensional CT ventilation images were created for 12 patients with emphysematous lung regions as observed on CT, using a total of four combinations of two deformable image registration (DIR) algorithms: surface-based (DIRsur) and volumetric (DIRvol), and two metrics: Hounsfield unit (HU) change (VHU) and Jacobian determinant of deformation (VJac), yielding four ventilation image sets per patient. Emphysematous lung regions were detected by density masking. We tested our hypothesis using the one-tailed t-test. Visually, different DIR algorithms and metrics yielded spatially variant 4D-CT ventilation images. The mean ventilation values in emphysematous lung regions were consistently lower than in non-emphysematous regions for all the combinations of DIR algorithms and metrics. VHU resulted in statistically significant differences for both DIRsur (0.14 ± 0.14 versus 0.29 ± 0.16, p = 0.01) and DIRvol (0.13 ± 0.13 versus 0.27 ± 0.15, p < 0.01). However, VJac resulted in non-significant differences for both DIRsur (0.15 ± 0.07 versus 0.17 ± 0.08, p = 0.20) and DIRvol (0.17 ± 0.08 versus 0.19 ± 0.09, p = 0.30). This study demonstrated the strong correlation between the HU-based 4D-CT ventilation and emphysema, which indicates the potential for HU-based 4D-CT ventilation imaging to achieve high physiologic accuracy. A further study is needed to confirm these results.

  2. Comparison of exogenous surfactant therapy, mechanical ventilation with high end-expiratory pressure and partial liquid ventilation in a model of acute lung injury.

    PubMed

    Hartog, A; Vazquez de Anda, G F; Gommers, D; Kaisers, U; Verbrugge, S J; Schnabel, R; Lachmann, B

    1999-01-01

    We have compared three treatment strategies, that aim to prevent repetitive alveolar collapse, for their effect on gas exchange, lung mechanics, lung injury, protein transfer into the alveoli and surfactant system, in a model of acute lung injury. In adult rats, the lungs were ventilated mechanically with 100% oxygen and a PEEP of 6 cm H2O, and acute lung injury was induced by repeated lung lavage to obtain a PaO2 value < 13 kPa. Animals were then allocated randomly (n = 12 in each group) to receive exogenous surfactant therapy, ventilation with high PEEP (18 cm H2O), partial liquid ventilation or ventilation with low PEEP (8 cm H2O) (ventilated controls). Blood-gas values were measured hourly. At the end of the 4-h study, in six animals per group, pressure-volume curves were constructed and bronchoalveolar lavage (BAL) was performed, whereas in the remaining animals lung injury was assessed. In the ventilated control group, arterial oxygenation did not improve and protein concentration of BAL and conversion of active to non-active surfactant components increased significantly. In the three treatment groups, PaO2 increased rapidly to > 50 kPa and remained stable over the next 4 h. The protein concentration of BAL fluid increased significantly only in the partial liquid ventilation group. Conversion of active to non-active surfactant components increased significantly in the partial liquid ventilation group and in the group ventilated with high PEEP. In the surfactant group and partial liquid ventilation groups, less lung injury was found compared with the ventilated control group and the group ventilated with high PEEP. We conclude that although all three strategies improved PaO2 to > 50 kPa, the impact on protein transfer into the alveoli, surfactant system and lung injury differed markedly.

  3. Multifaceted bench comparative evaluation of latest intensive care unit ventilators.

    PubMed

    Garnier, M; Quesnel, C; Fulgencio, J-P; Degrain, M; Carteaux, G; Bonnet, F; Similowski, T; Demoule, A

    2015-07-01

    Independent bench studies using specific ventilation scenarios allow testing of the performance of ventilators in conditions similar to clinical settings. The aims of this study were to determine the accuracy of the latest generation ventilators to deliver chosen parameters in various typical conditions and to provide clinicians with a comprehensive report on their performance. Thirteen modern intensive care unit ventilators were evaluated on the ASL5000 test lung with and without leakage for: (i) accuracy to deliver exact tidal volume (VT) and PEEP in assist-control ventilation (ACV); (ii) performance of trigger and pressurization in pressure support ventilation (PSV); and (iii) quality of non-invasive ventilation algorithms. In ACV, only six ventilators delivered an accurate VT and nine an accurate PEEP. Eleven devices failed to compensate VT and four the PEEP in leakage conditions. Inspiratory delays differed significantly among ventilators in invasive PSV (range 75-149 ms, P=0.03) and non-invasive PSV (range 78-165 ms, P<0.001). The percentage of the ideal curve (concomitantly evaluating the pressurization speed and the levels of pressure reached) also differed significantly (range 57-86% for invasive PSV, P=0.04; and 60-90% for non-invasive PSV, P<0.001). Non-invasive ventilation algorithms efficiently prevented the decrease in pressurization capacities and PEEP levels induced by leaks in, respectively, 10 and 12 out of the 13 ventilators. We observed real heterogeneity of performance amongst the latest generation of intensive care unit ventilators. Although non-invasive ventilation algorithms appear to maintain adequate pressurization efficiently in the case of leakage, basic functions, such as delivered VT in ACV and pressurization in PSV, are often less reliable than the values displayed by the device suggest. © The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. Setting individualized positive end-expiratory pressure level with a positive end-expiratory pressure decrement trial after a recruitment maneuver improves oxygenation and lung mechanics during one-lung ventilation.

    PubMed

    Ferrando, Carlos; Mugarra, Ana; Gutierrez, Andrea; Carbonell, Jose Antonio; García, Marisa; Soro, Marina; Tusman, Gerardo; Belda, Francisco Javier

    2014-03-01

    We investigated whether individualized positive end-expiratory pressure (PEEP) improves oxygenation, ventilation, and lung mechanics during one-lung ventilation compared with standardized PEEP. Thirty patients undergoing thoracic surgery were randomly allocated to the study or control group. Both groups received an alveolar recruitment maneuver at the beginning and end of one-lung ventilation. After the alveolar recruitment maneuver, the control group had their lungs ventilated with a 5 cm·H2O PEEP, while the study group had their lungs ventilated with an individualized PEEP level determined by a PEEP decrement trial. Arterial blood samples, lung mechanics, and volumetric capnography were recorded at multiple timepoints throughout the procedure. The individualized PEEP values in study group were higher than the standardized PEEP values (10 ± 2 vs 5 cm·H2O; P < 0.001). In both groups, arterial oxygenation decreased when bilateral-lung ventilation was switched to one-lung ventilation and increased after the alveolar recruitment maneuver. During one-lung ventilation, oxygenation was maintained in the study group but decreased in the control group. After one-lung ventilation, arterial oxygenation was significantly higher in the study group (306 vs 231 mm·Hg, P = 0.007). Static compliance decreased in both groups when bilateral-lung ventilation was switched to one-lung ventilation. Static compliance increased significantly only in the study group (P < 0.001) after the alveolar recruitment maneuver and optimal PEEP adjustment. The alveolar recruitment maneuver did not decrease cardiac index in any patient. During one-lung ventilation, the improvements in oxygenation and lung mechanics after an alveolar recruitment maneuver were better preserved by ventilation by using individualized PEEP with a PEEP decrement trial than with a standardized 5 cm·H2O of PEEP.

  5. Passive continuous positive airway pressure ventilation during cardiopulmonary resuscitation: a randomized cross-over manikin simulation study.

    PubMed

    Winkler, Bernd E; Muellenbach, Ralf M; Wurmb, Thomas; Struck, Manuel F; Roewer, Norbert; Kranke, Peter

    2017-02-01

    While controlled ventilation is most frequently used during cardiopulmonary resuscitation (CPR), the application of continuous positive airway pressure (CPAP) and passive ventilation of the lung synchronously with chest compressions and decompressions might represent a promising alternative approach. One benefit of CPAP during CPR is the reduction of peak airway pressures and therefore a potential enhancement in haemodynamics. We therefore evaluated the tidal volumes and airway pressures achieved during CPAP-CPR. During CPR with the LUCAS™ 2 compression device, a manikin model was passively ventilated at CPAP levels of 5, 10, 20 and 30 hPa with the Boussignac tracheal tube and the ventilators Evita ® V500, Medumat ® Transport, Oxylator ® EMX, Oxylog ® 2000, Oxylog ® 3000, Primus ® and Servo ® -i as well as the Wenoll ® diver rescue system. Tidal volumes and airway pressures during CPAP-CPR were recorded and analyzed. Tidal volumes during CPAP-CPR were higher than during compression-only CPR without positive airway pressure. The passively generated tidal volumes increased with increasing CPAP levels and were significantly influenced by the ventilators used. During ventilation at 20 hPa CPAP via a tracheal tube, the mean tidal volumes ranged from 125 ml (Medumat ® ) to 309 ml (Wenoll ® ) and the peak airway pressures from 23 hPa (Primus ® ) to 49 hPa (Oxylog ® 3000). Transport ventilators generated lower tidal volumes than intensive care ventilators or closed-circuit systems. Peak airway pressures during CPAP-CPR were lower than those during controlled ventilation CPR reported in literature. High peak airway pressures are known to limit the applicability of ventilation via facemask or via supraglottic airway devices and may adversely affect haemodynamics. Hence, the application of ventilators generating high tidal volumes with low peak airway pressures appears desirable during CPAP-CPR. The limited CPAP-CPR capabilities of transport ventilators in our study might be prerequisite for future developments of transport ventilators.

  6. [Guide for the use of jet-ventilation during ENT and oral surgery].

    PubMed

    Bourgain, J-L; Chollet, M; Fischler, M; Gueret, G; Mayne, A

    2010-10-01

    The aim of this synthesis was to give recommendations on the use of jet-ventilation during ENT surgical and endoscopy procedures. Literature was collected from PUBMED and analysed by the members of French association of anaesthesiologists in ENT surgery, all skilled in this field. Presentation of these recommendations was given during the general assembly held in Reims, the 15th May 2009. Jet-ventilation is especially indicated during upper airway endoscopy and laryngeal invasive endoscopic surgery. Furthermore, transtracheal jet ventilation is included on most of difficult oxygenation and difficult intubation algorithm. The main risk of jet-ventilation is pulmonary barotrauma when expiration of injected gas is impeded by an upper airway obstruction. Failure and complications of tracheal puncture are rare when performed by experimented operators. Clinical use of jet ventilation requires a dedicated device. Practice of jet ventilation without intubation may be dangerous when applied without control of driving pressure and end expiratory tracheal pressure. Every anaesthetist should be familiar with transtracheal ventilation since they may face a "cannot ventilate cannot intubate" situation. Upper airway endoscopy and laryngeal surgery are the ideal field for training jet ventilation, even more so as this technique offers perfect operative conditions. To apply this project, jet ventilation should be used more frequently in routine practice. To maintain skill, regular use of these techniques is required. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

  7. Noninvasive Ventilation in Premature Neonates.

    PubMed

    Flanagan, Keri Ann

    2016-04-01

    The use of noninvasive ventilation is a constantly evolving treatment option for respiratory disease in the premature infant. The goals of these noninvasive ventilation techniques are to improve gas exchange in the premature infant's lungs and to minimize the need for intubation and invasive mechanical ventilation. The goals of this article are to consider various uses of nasal interfaces, discuss skin care and developmental positioning concerns faced by the bedside nurse, and discuss the medical management aimed to reduce morbidity and mortality. This article explores the nursing role, the advances in medical strategies for noninvasive ventilation, and the team approach to noninvasive ventilation use in this population. Search strategy included a literature review on medical databases, such as EBSCOhost, CINAHL, PubMed, and NeoReviews. Innovative products, nursing research on developmental positioning and skin care, and advanced medical management have led to better and safer outcomes for premature infants requiring noninvasive ventilation. The medical focus of avoiding long-term mechanical ventilation would not be possible without the technology to provide noninvasive ventilation to these premature infants and the watchful eye of the nurse in terms of careful positioning, preventing skin breakdown and facial scarring, and a proper seal to maximize ventilation accuracy. This article encourages nursing-based research to quantify some of the knowledge about skin care and positioning as well as research into most appropriate uses for noninvasive ventilation devices.

  8. Weaning from mechanical ventilation: why are we still looking for alternative methods?

    PubMed

    Frutos-Vivar, F; Esteban, A

    2013-12-01

    Most patients who require mechanical ventilation for longer than 24 hours, and who improve the condition leading to the indication of ventilatory support, can be weaned after passing a first spontaneous breathing test. The challenge is to improve the weaning of patients who fail that first test. We have methods that can be referred to as traditional, such as the T-tube, pressure support or synchronized intermittent mandatory ventilation (SIMV). In recent years, however, new applications of usual techniques as noninvasive ventilation, new ventilation methods such as automatic tube compensation (ATC), mandatory minute ventilation (MMV), adaptive support ventilation or automatic weaning systems based on pressure support have been described. Their possible role in weaning from mechanical ventilation among patients with difficult or prolonged weaning remains to be established. Copyright © 2012 Elsevier España, S.L. and SEMICYUC. All rights reserved.

  9. Circuit compliance compensation in lung protective ventilation.

    PubMed

    Masselli, Grazia Maria Pia; Silvestri, Sergio; Sciuto, Salvatore Andrea; Cappa, Paolo

    2006-01-01

    Lung protective ventilation utilizes low tidal volumes to ventilate patients with severe lung pathologies. The compensation of breathing circuit effects, i.e. those induced by compressible volume of the circuit, results particularly critical in the calculation of the actual tidal volume delivered to patient's respiratory system which in turns is responsible of the level of permissive hypercapnia. The present work analyzes the applicability of the equation for circuit compressible volume compensation in the case of pressure and volume controlled lung protective ventilation. Experimental tests conducted in-vitro show that the actual tidal volume can be reliably estimated if the compliance of the breathing circuit is measured with the same parameters and ventilation technique that will be utilized in lung protective ventilation. Differences between volume and pressure controlled ventilation are also quantitatively assessed showing that pressure controlled ventilation allows a more reliable compensation of breathing circuit compressible volume.

  10. The Effect of Pressure-Controlled Ventilation and Volume-Controlled Ventilation in Prone Position on Pulmonary Mechanics and Inflammatory Markers.

    PubMed

    Şenay, Hasan; Sıvacı, Remziye; Kokulu, Serdar; Koca, Buğra; Bakı, Elif Doğan; Ela, Yüksel

    2016-08-01

    The aim of this present study is to compare the effect of pressure-controlled ventilation and volume-controlled ventilation on pulmonary mechanics and inflammatory markers in prone position. The study included 41 patients undergoing to vertebrae surgery. The patients were randomized into two groups: Group 1 received volume-controlled ventilation, while group 2 received pressure-controlled ventilation. The demographic data, pulmonary mechanics, the inflammatory marker levels just after the induction of anesthetics, at the 6th and 12th hours, and gas analysis from arterial blood samples taken at the beginning and the 30th minute were recorded. The inflammatory marker levels increased in both groups, without any significant difference among groups. Peak inspiratory pressure level was higher in the volume-controlled ventilation group. This study revealed that there is no difference regarding inflammatory marker levels between volume- and pressure-controlled ventilation.

  11. Pleural liquid and kinetic friction coefficient of mesothelium after mechanical ventilation.

    PubMed

    Bodega, Francesca; Sironi, Chiara; Porta, Cristina; Zocchi, Luciano; Agostoni, Emilio

    2015-01-15

    Volume and protein concentration of pleural liquid in anesthetized rabbits after 1 or 3h of mechanical ventilation, with alveolar pressure equal to atmospheric at end expiration, were compared to those occurring after spontaneous breathing. Moreover, coefficient of kinetic friction between samples of visceral and parietal pleura, obtained after spontaneous or mechanical ventilation, sliding in vitro at physiological velocity under physiological load, was determined. Volume of pleural liquid after mechanical ventilation was similar to that previously found during spontaneous ventilation. This finding is contrary to expectation of Moriondo et al. (2005), based on measurement of lymphatic and interstitial pressure. Protein concentration of pleural liquid after mechanical ventilation was also similar to that occurring after spontaneous ventilation. Coefficient of kinetic friction after mechanical ventilation was 0.023±0.001, similar to that obtained after spontaneous breathing. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Numerical simulation of volume-controlled mechanical ventilated respiratory system with 2 different lungs.

    PubMed

    Shi, Yan; Zhang, Bolun; Cai, Maolin; Zhang, Xiaohua Douglas

    2017-09-01

    Mechanical ventilation is a key therapy for patients who cannot breathe adequately by themselves, and dynamics of mechanical ventilation system is of great significance for life support of patients. Recently, models of mechanical ventilated respiratory system with 1 lung are used to simulate the respiratory system of patients. However, humans have 2 lungs. When the respiratory characteristics of 2 lungs are different, a single-lung model cannot reflect real respiratory system. In this paper, to illustrate dynamic characteristics of mechanical ventilated respiratory system with 2 different lungs, we propose a mathematical model of mechanical ventilated respiratory system with 2 different lungs and conduct experiments to verify the model. Furthermore, we study the dynamics of mechanical ventilated respiratory system with 2 different lungs. This research study can be used for improving the efficiency and safety of volume-controlled mechanical ventilation system. Copyright © 2016 John Wiley & Sons, Ltd.

  13. Continuous distributions of specific ventilation recovered from inert gas washout

    NASA Technical Reports Server (NTRS)

    Lewis, S. M.; Evans, J. W.; Jalowayski, A. A.

    1978-01-01

    A new technique is described for recovering continuous distributions of ventilation as a function of tidal ventilation/volume ratio from the nitrogen washout. The analysis yields a continuous distribution of ventilation as a function of tidal ventilation/volume ratio represented as fractional ventilations of 50 compartments plus dead space. The procedure was verified by recovering known distributions from data to which noise had been added. Using an apparatus to control the subject's tidal volume and FRC, mixed expired N2 data gave the following results: (a) the distributions of young, normal subjects were narrow and unimodal; (b) those of subjects over age 40 were broader with more poorly ventilated units; (c) patients with pulmonary disease of all descriptions showed enlarged dead space; (d) patients with cystic fibrosis showed multimodal distributions with the bulk of the ventilation going to overventilated units; and (e) patients with obstructive lung disease fell into several classes, three of which are illustrated.

  14. Feasibility of Protective Ventilation During Elective Supratentorial Neurosurgery: A Randomized, Crossover, Clinical Trial.

    PubMed

    Ruggieri, Francesco; Beretta, Luigi; Corno, Laura; Testa, Valentina; Martino, Enrico A; Gemma, Marco

    2017-06-30

    Traditional ventilation approaches, providing high tidal volumes (Vt), produce excessive alveolar distention and lung injury. Protective ventilation, employing lower Vt and positive end-expiratory pressure (PEEP), is an attractive alternative also for neuroanesthesia, when prolonged mechanical ventilation is needed. Nevertheless, protective ventilation during intracranial surgery may exert dangerous effects on intracranial pressure (ICP). We tested the feasibility of a protective ventilation strategy in neurosurgery. Our monocentric, double-blind, 1:1 randomized, 2×2 crossover study aimed at studying the effect size and variability of ICP in patients undergoing elective supratentorial brain tumor removal and alternatively ventilated with Vt 9 mL/kg-PEEP 0 mm Hg and Vt 7 mL/kg-PEEP 5 mm Hg. Respiratory rate was adjusted to maintain comparable end-tidal carbon dioxide between ventilation modes. ICP was measured through a subdural catheter inserted before dural opening. Forty patients were enrolled; 8 (15%) were excluded after enrollment. ICP did not differ between traditional and protective ventilation (11.28±5.37, 11 [7 to 14.5] vs. 11.90±5.86, 11 [8 to 15] mm Hg; P=0.541). End-tidal carbon dioxide (28.91±2.28, 29 [28 to 30] vs. 28.00±2.17, 28 [27 to 29] mm Hg; P<0.001). Peak airway pressure (17.25±1.97, 17 [16 to 18.5] vs. 15.81±2.87, 15.5 [14 to 17] mm Hg; P<0.001) and plateau airway pressure (16.06±2.30, 16 [14.5 to 17] vs. 14.19±2.82, 14 [12.5 to 16] mm Hg; P<0.001) were higher during protective ventilation. Blood pressure, heart rate, and body temperature did not differ between ventilation modes. Dural tension was "acceptable for surgery" in all cases. ICP differences between ventilation modes were not affected by ICP values under traditional ventilation (coefficient=0.067; 95% confidence interval, -0.278 to 0.144; P=0.523). Protective ventilation is a feasible alternative to traditional ventilation during elective neurosurgery.

  15. Variability in Usual Care Mechanical Ventilation for Pediatric Acute Respiratory Distress Syndrome: Time for a Decision Support Protocol?

    PubMed

    Newth, Christopher J L; Sward, Katherine A; Khemani, Robinder G; Page, Kent; Meert, Kathleen L; Carcillo, Joseph A; Shanley, Thomas P; Moler, Frank W; Pollack, Murray M; Dalton, Heidi J; Wessel, David L; Berger, John T; Berg, Robert A; Harrison, Rick E; Holubkov, Richard; Doctor, Allan; Dean, J Michael; Jenkins, Tammara L; Nicholson, Carol E

    2017-11-01

    Although pediatric intensivists philosophically embrace lung protective ventilation for acute lung injury and acute respiratory distress syndrome, we hypothesized that ventilator management varies. We assessed ventilator management by evaluating changes to ventilator settings in response to blood gases, pulse oximetry, or end-tidal CO2. We also assessed the potential impact that a pediatric mechanical ventilation protocol adapted from National Heart Lung and Blood Institute acute respiratory distress syndrome network protocols could have on reducing variability by comparing actual changes in ventilator settings to those recommended by the protocol. Prospective observational study. Eight tertiary care U.S. PICUs, October 2011 to April 2012. One hundred twenty patients (age range 17 d to 18 yr) with acute lung injury/acute respiratory distress syndrome. Two thousand hundred arterial and capillary blood gases, 3,964 oxygen saturation by pulse oximetry, and 2,757 end-tidal CO2 values were associated with 3,983 ventilator settings. Ventilation mode at study onset was pressure control 60%, volume control 19%, pressure-regulated volume control 18%, and high-frequency oscillatory ventilation 3%. Clinicians changed FIO2 by ±5 or ±10% increments every 8 hours. Positive end-expiratory pressure was limited at ~10 cm H2O as oxygenation worsened, lower than would have been recommended by the protocol. In the first 72 hours of mechanical ventilation, maximum tidal volume/kg using predicted versus actual body weight was 10.3 (8.5-12.9) (median [interquartile range]) versus 9.2 mL/kg (7.6-12.0) (p < 0.001). Intensivists made changes similar to protocol recommendations 29% of the time, opposite to the protocol's recommendation 12% of the time and no changes 56% of the time. Ventilator management varies substantially in children with acute respiratory distress syndrome. Opportunities exist to minimize variability and potentially injurious ventilator settings by using a pediatric mechanical ventilation protocol offering adequately explicit instructions for given clinical situations. An accepted protocol could also reduce confounding by mechanical ventilation management in a clinical trial.

  16. MO-A-BRD-05: Evaluation of Composed Lung Ventilation with 4DCT and Image Registration

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Du, K; Bayouth, J; Reinhardt, J

    Purpose: Regional pulmonary function can be derived using fourdimensional computed tomography (4DCT) combined with deformable image registration. However, only peak inhale and exhale phases have been used thus far while the lung ventilation during intermediate phases is not considered. In our previous work, we have investigated the spatiotemporal heterogeneity of lung ventilation and its dependence on respiration effort. In this study, composed ventilation is introduced using all inspiration phases and compared to direct ventilation. Both methods are evaluated against Xe-CT derived ventilation. Methods: Using an in-house tissue volume preserving deformable image registration, unlike the direct ventilation method, which computes frommore » end expiration to end inspiration, Jacobian ventilation maps were computed from one inhale phase to the next and then composed from all inspiration steps. The two methods were compared in both patients prior to RT and mechanically ventilated sheep subjects. In addition, they wereassessed for the correlation with Xe-CT derived ventilation in sheep subjects. Annotated lung landmarks were used to evaluate the accuracy of original and composed deformation field. Results: After registration, the landmark distance for composed deformation field was always higher than that for direct deformation field (0IN to 100IN average in human: 1.03 vs 1.53, p=0.001, and in sheep: 0.80 vs0.94, p=0.009), and both increased with longer phase interval. Direct and composed ventilation maps were similar in both sheep (gamma pass rate 87.6) and human subjects (gamma pass rate 71.9),and showed consistent pattern from ventral to dorsal when compared to Xe-CT derived ventilation. Correlation coefficient between Xe-CT and composed ventilation was slightly better than the direct method but not significant (average 0.89 vs 0.85, p=0.135). Conclusion: More strict breathing control in sheep subjects may explain higher similarity between direct and composed ventilation. When compared to Xe-CT ventilation, no significant difference was found for the composed method. NIH Grant: R01 CA166703.« less

  17. Prediction and outcomes of impossible mask ventilation: a review of 50,000 anesthetics.

    PubMed

    Kheterpal, Sachin; Martin, Lizabeth; Shanks, Amy M; Tremper, Kevin K

    2009-04-01

    There are no existing data regarding risk factors for impossible mask ventilation and limited data regarding its incidence. The authors sought to determine the incidence, predictors, and outcomes associated with impossible mask ventilation. The authors performed an observational study over a 4-yr period. For each adult patient undergoing a general anesthetic, preoperative patient characteristics, detailed airway physical exam, and airway outcome data were collected. The primary outcome was impossible mask ventilation defined as the inability to exchange air during bag-mask ventilation attempts, despite multiple providers, airway adjuvants, or neuromuscular blockade. Secondary outcomes included the final, definitive airway management technique and direct laryngoscopy view. The incidence of impossible mask ventilation was calculated. Independent (P < 0.05) predictors of impossible mask ventilation were identified by performing a logistic regression full model fit. Over a 4-yr period from 2004 to 2008, 53,041 attempts at mask ventilation were recorded. A total of 77 cases of impossible mask ventilation (0.15%) were observed. Neck radiation changes, male sex, sleep apnea, Mallampati III or IV, and presence of beard were identified as independent predictors. The receiver-operating-characteristic area under the curve for this model was 0.80 +/- 0.03. Nineteen impossible mask ventilation patients (25%) also demonstrated difficult intubation, with 15 being intubated successfully. Twelve patients required an alternative intubation technique, including two surgical airways and two patients who were awakened and underwent successful fiberoptic intubation. Impossible mask ventilation is an infrequent airway event that is associated with difficult intubation. Neck radiation changes represent the most significant clinical predictor of impossible mask ventilation in the patient dataset.

  18. Lung protective mechanical ventilation and two year survival in patients with acute lung injury: prospective cohort study

    PubMed Central

    Colantuoni, Elizabeth; Mendez-Tellez, Pedro A; Dinglas, Victor D; Sevransky, Jonathan E; Dennison Himmelfarb, Cheryl R; Desai, Sanjay V; Shanholtz, Carl; Brower, Roy G; Pronovost, Peter J

    2012-01-01

    Objective To evaluate the association of volume limited and pressure limited (lung protective) mechanical ventilation with two year survival in patients with acute lung injury. Design Prospective cohort study. Setting 13 intensive care units at four hospitals in Baltimore, Maryland, USA. Participants 485 consecutive mechanically ventilated patients with acute lung injury. Main outcome measure Two year survival after onset of acute lung injury. Results 485 patients contributed data for 6240 eligible ventilator settings, as measured twice daily (median of eight eligible ventilator settings per patient; 41% of which adhered to lung protective ventilation). Of these patients, 311 (64%) died within two years. After adjusting for the total duration of ventilation and other relevant covariates, each additional ventilator setting adherent to lung protective ventilation was associated with a 3% decrease in the risk of mortality over two years (hazard ratio 0.97, 95% confidence interval 0.95 to 0.99, P=0.002). Compared with no adherence, the estimated absolute risk reduction in two year mortality for a prototypical patient with 50% adherence to lung protective ventilation was 4.0% (0.8% to 7.2%, P=0.012) and with 100% adherence was 7.8% (1.6% to 14.0%, P=0.011). Conclusions Lung protective mechanical ventilation was associated with a substantial long term survival benefit for patients with acute lung injury. Greater use of lung protective ventilation in routine clinical practice could reduce long term mortality in patients with acute lung injury. Trial registration Clinicaltrials.gov NCT00300248. PMID:22491953

  19. Magical Boxes

    ERIC Educational Resources Information Center

    Costello, Judith

    2005-01-01

    Students get excited when they realize that they can transform a flat sheet of paper into a box. By using different sizes of paper, they can make different sizes of boxes and put a box inside a box, inside a box. These magical boxes within boxes can contain unwanted emotions or special treasures. The project described in this article incorporates…

  20. Trends in mechanical ventilation: are we ventilating our patients in the best possible way?

    PubMed Central

    Veneroni, Chiara; Farre’, Ramon

    2017-01-01

    This review addresses how the combination of physiology, medicine and engineering principles contributed to the development and advancement of mechanical ventilation, emphasising the most urgent needs for improvement and the most promising directions of future development. Several aspects of mechanical ventilation are introduced, highlighting on one side the importance of interdisciplinary research for further development and, on the other, the importance of training physicians sufficiently on the technological aspects of modern devices to exploit properly the great complexity and potentials of this treatment. Educational aims To learn how mechanical ventilation developed in recent decades and to provide a better understanding of the actual technology and practice. To learn how and why interdisciplinary research and competences are necessary for providing the best ventilation treatment to patients. To understand which are the most relevant technical limitations in modern mechanical ventilators that can affect their performance in delivery of the treatment. To better understand and classify ventilation modes. To learn the classification, benefits, drawbacks and future perspectives of automatic ventilation tailoring algorithms. PMID:28620428

  1. Analysis of the systems of ventilation of residential houses of Ukraine and Estonia

    NASA Astrophysics Data System (ADS)

    Savchenko, Olena; Zhelykh, Vasyl; Voll, Hendrik

    2017-12-01

    The most common ventilation system in residential buildings in Ukraine is natural ventilation. In recent years, due to increased tightness of structures, an increase in the content of synthetic finishing materials in them, the quality of microclimate parameters deteriorated. One of the measures to improve the parameters of indoor air in residential buildings is the use of mechanical inflow and exhaust ventilation system. In this article the regulatory documents concerning the design of ventilation systems in Ukraine and Estonia and the requirements for air exchange in residential buildings are considered. It is established that the existing normative documents in Ukraine are analogous to European norms, which allow design the system of ventilation of residential buildings according to European standards. However, the basis for the design of ventilation systems in Ukraine is the national standards, in which mechanical ventilation, unfortunately, is provided only for the design of high-rise buildings. To maintain acceptable microclimate parameters in residential buildings, it is advisable for designers to apply the requirements for designing ventilation systems in accordance with European standards.

  2. Natural ventilation for the prevention of airborne contagion.

    PubMed

    Escombe, A Roderick; Oeser, Clarissa C; Gilman, Robert H; Navincopa, Marcos; Ticona, Eduardo; Pan, William; Martínez, Carlos; Chacaltana, Jesus; Rodríguez, Richard; Moore, David A J; Friedland, Jon S; Evans, Carlton A

    2007-02-01

    Institutional transmission of airborne infections such as tuberculosis (TB) is an important public health problem, especially in resource-limited settings where protective measures such as negative-pressure isolation rooms are difficult to implement. Natural ventilation may offer a low-cost alternative. Our objective was to investigate the rates, determinants, and effects of natural ventilation in health care settings. The study was carried out in eight hospitals in Lima, Peru; five were hospitals of "old-fashioned" design built pre-1950, and three of "modern" design, built 1970-1990. In these hospitals 70 naturally ventilated clinical rooms where infectious patients are likely to be encountered were studied. These included respiratory isolation rooms, TB wards, respiratory wards, general medical wards, outpatient consulting rooms, waiting rooms, and emergency departments. These rooms were compared with 12 mechanically ventilated negative-pressure respiratory isolation rooms built post-2000. Ventilation was measured using a carbon dioxide tracer gas technique in 368 experiments. Architectural and environmental variables were measured. For each experiment, infection risk was estimated for TB exposure using the Wells-Riley model of airborne infection. We found that opening windows and doors provided median ventilation of 28 air changes/hour (ACH), more than double that of mechanically ventilated negative-pressure rooms ventilated at the 12 ACH recommended for high-risk areas, and 18 times that with windows and doors closed (p < 0.001). Facilities built more than 50 years ago, characterised by large windows and high ceilings, had greater ventilation than modern naturally ventilated rooms (40 versus 17 ACH; p < 0.001). Even within the lowest quartile of wind speeds, natural ventilation exceeded mechanical (p < 0.001). The Wells-Riley airborne infection model predicted that in mechanically ventilated rooms 39% of susceptible individuals would become infected following 24 h of exposure to untreated TB patients of infectiousness characterised in a well-documented outbreak. This infection rate compared with 33% in modern and 11% in pre-1950 naturally ventilated facilities with windows and doors open. Opening windows and doors maximises natural ventilation so that the risk of airborne contagion is much lower than with costly, maintenance-requiring mechanical ventilation systems. Old-fashioned clinical areas with high ceilings and large windows provide greatest protection. Natural ventilation costs little and is maintenance free, and is particularly suited to limited-resource settings and tropical climates, where the burden of TB and institutional TB transmission is highest. In settings where respiratory isolation is difficult and climate permits, windows and doors should be opened to reduce the risk of airborne contagion.

  3. 46 CFR 194.20-5 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS HANDLING, USE, AND... Ventilation. (a) Chemical storerooms shall be equipped with a power ventilation system of exhaust type. The... based upon the volume of the compartment. (1) Power ventilation units shall have nonsparking impellers...

  4. VENTILATION TECHNOLOGY SYSTEMS ANALYSIS

    EPA Science Inventory

    The report gives results of a project to develop a systems analysis of ventilation technology and provide a state-of-the-art assessment of ventilation and indoor air quality (IAQ) research needs. (NOTE: Ventilation technology is defined as the hardware necessary to bring outdoor ...

  5. 14 CFR 125.117 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Ventilation. 125.117 Section 125.117 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS....117 Ventilation. Each passenger or crew compartment must be suitably ventilated. Carbon monoxide...

  6. SY Tank Farm ventilation isolation option risk assessment report

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Powers, T.B.; Morales, S.D.

    The safety of the 241-SY Tank Farm ventilation system has been under extensive scrutiny due to safety concerns associated with tank 101-SY. Hydrogen and other gases are generated and trapped in the waste below the liquid surface. Periodically, these gases are released into the dome space and vented through the exhaust system. This attention to the ventilation system has resulted in the development of several alternative ventilation system designs. The ventilation system provides the primary means of mitigation of accidents associated with flammable gases. This report provides an assessment of various alternatives ventilation system designs.

  7. Design and calibration of a high-frequency oscillatory ventilator.

    PubMed

    Simon, B A; Mitzner, W

    1991-02-01

    High-frequency ventilation (HFV) is a modality of mechanical ventilation which presents difficult technical demands to the clinical or laboratory investigator. The essential features of an ideal HFV system are described, including wide frequency range, control of tidal volume and mean airway pressure, minimal dead space, and high effective internal impedance. The design and performance of a high-frequency oscillatory ventilation system is described which approaches these requirements. The ventilator utilizes a linear motor regulated by a closed loop controller and driving a novel frictionless double-diaphragm piston pump. Finally, the ventilator performance is tested using the impedance model of Venegas [1].

  8. Performance of ICU ventilators during noninvasive ventilation with large leaks in a total face mask: a bench study* **

    PubMed Central

    Nakamura, Maria Aparecida Miyuki; Costa, Eduardo Leite Vieira; Carvalho, Carlos Roberto Ribeiro; Tucci, Mauro Roberto

    2014-01-01

    Objective: Discomfort and noncompliance with noninvasive ventilation (NIV) interfaces are obstacles to NIV success. Total face masks (TFMs) are considered to be a very comfortable NIV interface. However, due to their large internal volume and consequent increased CO2 rebreathing, their orifices allow proximal leaks to enhance CO2 elimination. The ventilators used in the ICU might not adequately compensate for such leakage. In this study, we attempted to determine whether ICU ventilators in NIV mode are suitable for use with a leaky TFM. Methods: This was a bench study carried out in a university research laboratory. Eight ICU ventilators equipped with NIV mode and one NIV ventilator were connected to a TFM with major leaks. All were tested at two positive end-expiratory pressure (PEEP) levels and three pressure support levels. The variables analyzed were ventilation trigger, cycling off, total leak, and pressurization. Results: Of the eight ICU ventilators tested, four did not work (autotriggering or inappropriate turning off due to misdetection of disconnection); three worked with some problems (low PEEP or high cycling delay); and one worked properly. Conclusions: The majority of the ICU ventilators tested were not suitable for NIV with a leaky TFM. PMID:25029653

  9. A taxonomy for mechanical ventilation: 10 fundamental maxims.

    PubMed

    Chatburn, Robert L; El-Khatib, Mohamad; Mireles-Cabodevila, Eduardo

    2014-11-01

    The American Association for Respiratory Care has declared a benchmark for competency in mechanical ventilation that includes the ability to "apply to practice all ventilation modes currently available on all invasive and noninvasive mechanical ventilators." This level of competency presupposes the ability to identify, classify, compare, and contrast all modes of ventilation. Unfortunately, current educational paradigms do not supply the tools to achieve such goals. To fill this gap, we expand and refine a previously described taxonomy for classifying modes of ventilation and explain how it can be understood in terms of 10 fundamental constructs of ventilator technology: (1) defining a breath, (2) defining an assisted breath, (3) specifying the means of assisting breaths based on control variables specified by the equation of motion, (4) classifying breaths in terms of how inspiration is started and stopped, (5) identifying ventilator-initiated versus patient-initiated start and stop events, (6) defining spontaneous and mandatory breaths, (7) defining breath sequences (8), combining control variables and breath sequences into ventilatory patterns, (9) describing targeting schemes, and (10) constructing a formal taxonomy for modes of ventilation composed of control variable, breath sequence, and targeting schemes. Having established the theoretical basis of the taxonomy, we demonstrate a step-by-step procedure to classify any mode on any mechanical ventilator. Copyright © 2014 by Daedalus Enterprises.

  10. Accuracy of tidal volume delivered by home mechanical ventilation during mouthpiece ventilation

    PubMed Central

    Prigent, Helene; Falaize, Line; Leroux, Karl; Santos, Dante; Vaugier, Isabelle; Orlikowski, David; Lofaso, Frederic

    2016-01-01

    The aim of our study was to evaluate efficacy and reliability of currently available ventilators for mouthpiece ventilation (MPV). Five life-support home ventilators were assessed in a bench test using different settings simulating the specificities of MPV, such as intermittent circuit disconnection and presence of continuous leaks. The intermittent disconnection of the circuit caused relevant swings in the delivered tidal volume (VT), showing a VT overshoot during the disconnection periods and a VT decrease when the interface was reconnected to the test lung. The five ventilators showed substantial differences in the number of respiratory cycles necessary to reach a stable VT in the volume-controlled setting, ranging from 1.3 ± 0.6 to 7.3 ± 1.2 cycles. These differences were less accentuated in the volume-assisted setting (MPV-dedicated mode, when available). Our data show large differences in the capacity of the different ventilators to deal with the rapidly changing respiratory load features that characterize MPV, which can be further accentuated according to the used ventilator setting. The dedicated MPV modes allow improvement in the performance of ventilators only in some defined situations. This has practical consequences for the choice of the ventilator to be used for MPV in a specific patient. PMID:27146811

  11. An easy tool to assess ventilation in health facilities as part of air-borne transmission prevention: a cross-sectional survey from Uganda.

    PubMed

    Brouwer, Miranda; Katamba, Achilles; Katabira, Elly Tebasoboke; van Leth, Frank

    2017-05-03

    No guidelines exist on assessing ventilation through air changes per hour (ACH) using a vaneometer. The objective of the study was to evaluate the position and frequency for measuring air velocity using a vaneometer to assess ventilation with ACH; and to assess influence of ambient temperature and weather on ACH. Cross-sectional survey in six urban health facilities in Kampala, Uganda. Measurements consisted of taking air velocity on nine separate moments in five positions in each opening of the TB clinic, laboratory, outpatient consultation and outpatient waiting room using a vaneometer. We assessed in addition the ventilation with the "20% rule", and compared this estimation with the ventilation in ACH assessed using the vaneometer. A total of 189 measurements showed no influence on air velocity of the position and moment of the measurement. No significant influence existed of ambient temperature and a small but significant influence of sunny weather. Ventilation was adequate in 17/24 (71%) of all measurements. Using the "20% rule", ventilation was adequate in 50% of rooms assessed. Agreement between both methods existed in 13/23 (56%) of the rooms assessed. Most rooms had adequate ventilation when assessed using a vaneometer for measuring air velocity. A single vaneometer measurement of air velocity is adequate to assess ventilation in this setting. These findings provide practical input for clear guidelines on assessing ventilation using a vaneometer. Assessing ventilation with a vaneometer differs substantially from applying the "20% rule".

  12. Ventilation of carbon monoxide from a biomass pellet storage tank--a study of the effects of variation of temperature and cross-ventilation on the efficiency of natural ventilation.

    PubMed

    Emhofer, Waltraud; Lichtenegger, Klaus; Haslinger, Walter; Hofbauer, Hermann; Schmutzer-Roseneder, Irene; Aigenbauer, Stefan; Lienhard, Martin

    2015-01-01

    Wood pellets have been reported to emit toxic gaseous emissions during transport and storage. Carbon monoxide (CO) emission, due to the high toxicity of the gas and the possibility of it being present at high levels, is the most imminent threat to be considered before entering a pellet storage facility. For small-scale (<30 tons storage capacity) residential pellet storage facilities, ventilation, preferably natural ventilation utilizing already existing openings, has become the most favored solution to overcome the problem of high CO concentrations. However, there is little knowledge on the ventilation rates that can be reached and thus on the effectiveness of such measures. The aim of the study was to investigate ventilation rates for a specific small-scale pellet storage system depending on characteristic temperature differences. Furthermore, the influence of the implementation of a chimney and the influence of cross-ventilation on the ventilation rates were investigated. The air exchange rates observed in the experiments ranged between close to zero and up to 8 m(3) h(-1), depending largely on the existing temperature differences and the existence of cross-ventilation. The results demonstrate that implementing natural ventilation is a possible measure to enhance safety from CO emissions, but not one without limitations. © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  13. Incidence and prognosis of ventilator-associated tracheobronchitis (TAVeM): a multicentre, prospective, observational study.

    PubMed

    Martin-Loeches, Ignacio; Povoa, Pedro; Rodríguez, Alejandro; Curcio, Daniel; Suarez, David; Mira, Jean-Paul; Cordero, Maria Lourdes; Lepecq, Raphaël; Girault, Christophe; Candeias, Carlos; Seguin, Philippe; Paulino, Carolina; Messika, Jonathan; Castro, Alejandro G; Valles, Jordi; Coelho, Luis; Rabello, Ligia; Lisboa, Thiago; Collins, Daniel; Torres, Antonio; Salluh, Jorge; Nseir, Saad

    2015-11-01

    Ventilator-associated tracheobronchitis has been suggested as an intermediate process between tracheobronchial colonisation and ventilator-associated pneumonia in patients receiving mechanical ventilation. We aimed to establish the incidence and effect of ventilator-associated tracheobronchitis in a large, international patient cohort. We did a multicentre, prospective, observational study in 114 intensive care units (ICU) in Spain, France, Portugal, Brazil, Argentina, Ecuador, Bolivia, and Colombia over a preplanned time of 10 months. All patients older than 18 years admitted to an ICU who received invasive mechanical ventilation for more than 48 h were eligible. We prospectively obtained data for incidence of ventilator-associated lower respiratory tract infections, defined as ventilator-associated tracheobronchitis or ventilator-associated pneumonia. We grouped patients according to the presence or absence of such infections, and obtained data for the effect of appropriate antibiotics on progression of tracheobronchitis to pneumonia. Patients were followed up until death or discharge from hospital. To account for centre effects with a binary outcome, we fitted a generalised estimating equation model with a logit link, exchangeable correlation structure, and non-robust standard errors. This trial is registered with ClinicalTrials.gov, number NCT01791530. Between Sept 1, 2013, and July 31, 2014, we obtained data for 2960 eligible patients, of whom 689 (23%) developed ventilator-associated lower respiratory tract infections. The incidence of ventilator-associated tracheobronchitis and that of ventilator-associated pneumonia at baseline were similar (320 [11%; 10·2 of 1000 mechanically ventilated days] vs 369 [12%; 8·8 of 1000 mechanically ventilated days], p=0·48). Of the 320 patients with tracheobronchitis, 250 received appropriate antibiotic treatment and 70 received inappropriate antibiotics. 39 patients with tracheobronchitis progressed to pneumonia; however, the use of appropriate antibiotic therapy for tracheobronchitis was associated with significantly lower progression to pneumonia than was inappropriate treatment (19 [8%] of 250 vs 20 [29%] of 70, p<0·0001; crude odds ratio 0·21 [95% CI 0·11-0·41]). Significantly more patients with ventilator-associated pneumonia died (146 [40%] of 369) than those with tracheobronchitis (93 [29%] of 320) or absence of ventilator-associated lower respiratory tract infections (673 [30%] of 2271, p<0·0001). Median time to discharge from the ICU for survivors was significantly longer in the tracheobronchitis (21 days [IQR 15-34]) and pneumonia (22 [13-36]) groups than in the group with no ventilator-associated lower respiratory tract infections (12 [8-20]; hazard ratio 1·65 [95% CI 1·38-1·97], p<0·0001). This large database study emphasises that ventilator-associated tracheobronchitis is a major health problem worldwide, associated with high resources consumption in all countries. Our findings also show improved outcomes with use of appropriate antibiotic treatment for both ventilator-associated tracheobronchitis and ventilator-associated pneumonia, underlining the importance of treating both infections, since inappropriate treatment of tracheobronchitis was associated with a higher risk of progression to pneumonia. None. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Medical and Safety Reforms in Boxing

    PubMed Central

    Jordan, Barry D.

    1988-01-01

    The continued existence of boxing as an accepted sport in civilized society has been long debated. The position of the American Medical Association (AMA) has evolved from promoting increased safety and medical reform to recommending total abolition of both amateur and professional boxing. In response to the AMA opposition to boxing, the boxing community has attempted to increase the safeguards in amateur and professional boxing. The United States of America Amateur Boxing Federation, which is the national regulatory agency for all amateur boxing in the United States, has taken several actions to prevent the occurrence of acute brain injury and is currently conducting epidemiologic studies to assess the long-term neuropsychologic consequences of amateur boxing. In professional boxing, state regulatory agencies such as the New York State Athletic Commission have introduced several medical interventions to prevent and reduce neurologic injury. The lack of a national regulatory agency to govern professional boxing has stimulated the formation of the Association of Boxing Commissions and potential legislation for the federal regulation of professional boxing by a federally chartered organization called the United States Boxing Commission. The AMA's opposition to boxing and the medical and safety reforms implemented by the proponents of boxing are discussed. PMID:3385788

  15. Low Tidal Volume Ventilation in Patients without Acute Respiratory Distress Syndrome: A Paradigm Shift in Mechanical Ventilation

    PubMed Central

    Lipes, Jed; Bojmehrani, Azadeh; Lellouche, Francois

    2012-01-01

    Protective ventilation with low tidal volume has been shown to reduce morbidity and mortality in patients suffering from acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Low tidal volume ventilation is associated with particular clinical challenges and is therefore often underutilized as a therapeutic option in clinical practice. Despite some potential difficulties, data have been published examining the application of protective ventilation in patients without lung injury. We will briefly review the physiologic rationale for low tidal volume ventilation and explore the current evidence for protective ventilation in patients without lung injury. In addition, we will explore some of the potential reasons for its underuse and provide strategies to overcome some of the associated clinical challenges. PMID:22536499

  16. Hydrotherapy for the long-term ventilated patient: A case study and implications for practice.

    PubMed

    Wegner, Sally; Thomas, Peter; James, Christine

    2017-11-01

    Hydrotherapy of mechanically ventilated patients has been shown to be safe and feasible in both the acute stages of critical illness and in those requiring long term mechanical ventilation. This case study describes the hydrotherapy sessions of a 36 year old female, who after suffering complications of pneumococcal meningitis, became an incomplete quadriplegic and required long term mechanical ventilation. When implementing hydrotherapy with patients on mechanical ventilation a number of factors should be considered. These include staff resources and training, airway and ventilation management, patient preparation and safety procedures. Hydrotherapy can be safely utilised with mechanically ventilated patients, and may facilitate a patient's ability to participate in active exercise and rehabilitation. Copyright © 2017 Australian College of Critical Care Nurses Ltd. All rights reserved.

  17. Ventilation for an enclosure of a gas turbine and related method

    DOEpatents

    Schroeder, Troy Joseph; Leach, David; O'Toole, Michael Anthony

    2002-01-01

    A ventilation scheme for a rotary machine supported on pedestals within an enclosure having a roof, end walls and side walls with the machine arranged parallel to the side walls, includes ventilation air inlets located in a first end wall of the enclosure; a barrier wall located within the enclosure, proximate the first end wall to thereby create a plenum chamber. The barrier wall is constructed to provide a substantially annular gap between the barrier wall and a casing of the turbine to thereby direct ventilation air axially along the turbine; one or more ventilation air outlets located proximate a second, opposite end wall on the roof of the enclosure. In addition, one or more fans are provided for pulling ventilating air into said plenum chamber via the ventilation air inlets.

  18. Effect of leak and breathing pattern on the accuracy of tidal volume estimation by commercial home ventilators: a bench study.

    PubMed

    Luján, Manel; Sogo, Ana; Pomares, Xavier; Monsó, Eduard; Sales, Bernat; Blanch, Lluís

    2013-05-01

    New home ventilators are able to provide clinicians data of interest through built-in software. Monitoring of tidal volume (VT) is a key point in the assessment of the efficacy of home mechanical ventilation. To assess the reliability of the VT provided by 5 ventilators in a bench test. Five commercial ventilators from 4 different manufacturers were tested in pressure support mode with the help of a breathing simulator under different conditions of mechanical respiratory pattern, inflation pressure, and intentional leakage. Values provided by the built-in software of each ventilator were compared breath to breath with the VT monitored through an external pneumotachograph. Ten breaths for each condition were compared for every tested situation. All tested ventilators underestimated VT (ranges of -21.7 mL to -83.5 mL, which corresponded to -3.6% to -14.7% of the externally measured VT). A direct relationship between leak and underestimation was found in 4 ventilators, with higher underestimations of the VT when the leakage increased, ranging between -2.27% and -5.42% for each 10 L/min increase in the leakage. A ventilator that included an algorithm that computes the pressure loss through the tube as a function of the flow exiting the ventilator had the minimal effect of leaks on the estimation of VT (0.3%). In 3 ventilators the underestimation was also influenced by mechanical pattern (lower underestimation with restrictive, and higher with obstructive). The inclusion of algorithms that calculate the pressure loss as a function of the flow exiting the ventilator in commercial models may increase the reliability of VT estimation.

  19. Influence of Mechanical Ventilation on the Incidence of Pneumothorax During Infraclavicular Subclavian Vein Catheterization: A Prospective Randomized Noninferiority Trial.

    PubMed

    Kim, Eugene; Kim, Hyun Joo; Hong, Deok Man; Park, Hee-Pyoung; Bahk, Jae-Hyon

    2016-09-01

    It remains unclear whether we have to interrupt mechanical ventilation during infraclavicular subclavian venous catheterization. In practice, the clinicians' choice about lung deflation depends on their own discretion. The purpose of this study was to assess the influence of mechanical ventilation on the incidence of pneumothorax during infraclavicular subclavian venous catheterization. A total of 332 patients, who needed subclavian venous catheterization, were randomly assigned to 1 of the 2 groups: catheterizations were performed with the patients' lungs under mechanical ventilation (ventilation group, n = 165) or without mechanical ventilation (deflation group, n = 167). The incidences of pneumothorax and other complications such as arterial puncture, hemothorax, or catheter misplacements and the success rate of catheterization were compared. The incidences of pneumothorax were 0% (0/165) in the ventilation group and 0.6% (1/167) in the deflation group. The incidence of pneumothorax in the deflation group was 0.6% higher than that in the ventilation group and the 2-sided 90% confidence interval for the difference was (-1.29% to 3.44%). Because the lower bound for the 2-sided 90% confidence interval, -1.29%, was higher than the predefined noninferiority margin of -3%, the inferiority of the ventilation group over the deflation group was rejected at the .05 level of significance. Other complication rates and success rates of catheterization were comparable between 2 groups. The oxygen saturation dropped below 95% in 9 patients in the deflation group, while none in the ventilation group (P = .007). The success and complication rates were similar regardless of mechanical ventilation. During infraclavicular subclavian venous catheterization, interruption of mechanical ventilation does not seem to be necessary for the prevention of pneumothorax.

  20. Feasibility of the capnogram to monitor ventilation rate during cardiopulmonary resuscitation.

    PubMed

    Aramendi, Elisabete; Elola, Andoni; Alonso, Erik; Irusta, Unai; Daya, Mohamud; Russell, James K; Hubner, Pia; Sterz, Fritz

    2017-01-01

    The rates of chest compressions (CCs) and ventilations are both important metrics to monitor the quality of cardiopulmonary resuscitation (CPR). Capnography permits monitoring ventilation, but the CCs provided during CPR corrupt the capnogram and compromise the accuracy of automatic ventilation detectors. The aim of this study was to evaluate the feasibility of an automatic algorithm based on the capnogram to detect ventilations and provide feedback on ventilation rate during CPR, specifically addressing intervals where CCs are delivered. The dataset used to develop and test the algorithm contained in-hospital and out-of-hospital cardiac arrest episodes. The method relies on adaptive thresholding to detect ventilations in the first derivative of the capnogram. The performance of the detector was reported in terms of sensitivity (SE) and Positive Predictive Value (PPV). The overall performance was reported in terms of the rate error and errors in the hyperventilation alarms. Results were given separately for the intervals with CCs. A total of 83 episodes were considered, resulting in 4880min and 46,740 ventilations (8741 during CCs). The method showed an overall SE/PPV above 99% and 97% respectively, even in intervals with CCs. The error for the ventilation rate was below 1.8min -1 in any group, and >99% of the ventilation alarms were correctly detected. A method to provide accurate feedback on ventilation rate using only the capnogram is proposed. Its accuracy was proven even in intervals where canpography signal was severely corrupted by CCs. This algorithm could be integrated into monitor/defibrillators to provide reliable feedback on ventilation rate during CPR. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  1. Management and outcome of mechanically ventilated neurologic patients.

    PubMed

    Pelosi, Paolo; Ferguson, Niall D; Frutos-Vivar, Fernando; Anzueto, Antonio; Putensen, Christian; Raymondos, Konstantinos; Apezteguia, Carlos; Desmery, Pablo; Hurtado, Javier; Abroug, Fekri; Elizalde, José; Tomicic, Vinko; Cakar, Nahit; Gonzalez, Marco; Arabi, Yaseen; Moreno, Rui; Esteban, Andres

    2011-06-01

    To describe and compare characteristics, ventilatory practices, and associated outcomes among mechanically ventilated patients with different types of brain injury and between neurologic and nonneurologic patients. Secondary analysis of a prospective, observational, and multicenter study on mechanical ventilation. Three hundred forty-nine intensive care units from 23 countries. We included 552 mechanically ventilated neurologic patients (362 patients with stroke and 190 patients with brain trauma). For comparison we used a control group of 4,030 mixed patients who were ventilated for nonneurologic reasons. None. We collected demographics, ventilatory settings, organ failures, and complications arising during ventilation and outcomes. Multivariate logistic regression analysis was performed with intensive care unit mortality as the dependent variable. At admission, a Glasgow Coma Scale score ≤8 was observed in 68% of the stroke, 77% of the brain trauma, and 29% of the nonneurologic patients. Modes of ventilation and use of a lung-protective strategy within the first week of mechanical ventilation were similar between groups. In comparison with nonneurologic patients, patients with neurologic disease developed fewer complications over the course of mechanical ventilation with the exception of a higher rate of ventilator-associated pneumonia in the brain trauma cohort. Neurologic patients showed higher rates of tracheotomy and longer duration of mechanical ventilation. Mortality in the intensive care unit was significantly (p < .001) higher in patients with stroke (45%) than in brain trauma (29%) and nonneurologic disease (30%). Factors associated with mortality were: stroke (in comparison to brain trauma), Glasgow Coma Scale score on day 1, and severity at admission in the intensive care unit. In our study, one of every five mechanically ventilated patients received this therapy as a result of a neurologic disease. This cohort of patients showed a higher mortality rate than nonneurologic patients despite a lower incidence of extracerebral organ dysfunction.

  2. Analysis of a Pediatric Home Mechanical Ventilator Population.

    PubMed

    Amirnovin, Rambod; Aghamohammadi, Sara; Riley, Carley; Woo, Marlyn S; Del Castillo, Sylvia

    2018-05-01

    The population of children requiring home mechanical ventilation has evolved over the years and has grown to include a variety of diagnoses and needs that have led to changes in the care of this unique population. The purpose of this study was to provide a descriptive analysis of pediatric patients requiring home mechanical ventilation after hospitalization and how the evolution of this technology has impacted their care. A retrospective, observational, longitudinal analysis of 164 children enrolled in a university-affiliated home mechanical ventilation program over 26 years was performed. Data included each child's primary diagnosis, date of tracheostomy placement, duration of mechanical ventilation during hospitalization that consisted of home mechanical ventilator initiation, total length of pediatric ICU stay, ventilator settings at time of discharge from pediatric ICU, and disposition (home, facility, or died). Univariate, bivariate, and regression analysis was used as appropriate. The most common diagnosis requiring the use of home mechanical ventilation was neuromuscular disease (53%), followed by chronic pulmonary disease (29%). The median length of stay in the pediatric ICU decreased significantly after the implementation of a ventilator ward (70 d [30-142] vs 36 d [18-67], P = .02). The distribution of subjects upon discharge was home (71%), skilled nursing facility (24%), and died (4%), with an increase in the proportion of subjects discharged on PEEP and those going to nursing facilities over time ( P = 0.02). The evolution of home mechanical ventilation has allowed earlier transition out of the pediatric ICU and with increasing disposition to skilled nursing facilities over time. There has also been a change in ventilator management, including increased use of PEEP upon discharge, possibly driven by changes in ventilators and in-patient practice patterns. Copyright © 2018 by Daedalus Enterprises.

  3. Protective lung ventilation in operating room: a systematic review.

    PubMed

    Futier, E; Constantin, J M; Jaber, S

    2014-06-01

    Postoperative pulmonary and extrapulmonary complications adversely affect clinical outcomes and healthcare utilization, so that prevention has become a measure of the quality of perioperative care. Mechanical ventilation is an essential support therapy to maintain adequate gas exchange during general anesthesia for surgery. Mechanical ventilation using high tidal volume (VT) (between 10 and 15 mL/kg) has been historically encouraged to prevent hypoxemia and atelectasis formation in anesthetized patients undergoing abdominal and thoracic surgery. However, there is accumulating evidence from both experimental and clinical studies that mechanical ventilation, especially the use of high VT and plateau pressure, may potentially aggravate or even initiate lung injury. Ventilator-associated lung injury can result from cyclic alveolar overdistension of non-dependent lung tissue, and repetitive opening and closing of dependent lung tissue resulting in ultrastructural damage at the junction of closed and open alveoli. Lung-protective ventilation, which refers to the use of lower VT and limited plateau pressure to minimize overdistension, and positive end-expiratory pressure to prevent alveolar collapse at end-expiration, was shown to improve outcome in critically ill patients with acute respiratory distress syndrome (ARDS). It has been recently suggested that this approach might also be beneficial in a broader population, especially in critically ill patients without ARDS at the onset of mechanical ventilation. There is, however, little evidence regarding a potential beneficial effect of lung protective ventilation during surgery, especially in patients with healthy lungs. Although surgical patients are frequently exposed to much shorter periods of mechanical ventilation, this is an important gap in knowledge given the number of patients receiving mechanical ventilation in the operating room. This review developed the benefits of lung protective ventilation during surgery and general anesthesia and offers some recommendations for mechanical ventilation in the surgical context.

  4. Autophagy in pulmonary macrophages mediates lung inflammatory injury via NLRP3 inflammasome activation during mechanical ventilation

    PubMed Central

    Zhang, Yang; Liu, Gongjian; Dull, Randal O.; Schwartz, David E.

    2014-01-01

    The inflammatory response is a primary mechanism in the pathogenesis of ventilator-induced lung injury. Autophagy is an essential, homeostatic process by which cells break down their own components. We explored the role of autophagy in the mechanisms of mechanical ventilation-induced lung inflammatory injury. Mice were subjected to low (7 ml/kg) or high (28 ml/kg) tidal volume ventilation for 2 h. Bone marrow-derived macrophages transfected with a scrambled or autophagy-related protein 5 small interfering RNA were administered to alveolar macrophage-depleted mice via a jugular venous cannula 30 min before the start of the ventilation protocol. In some experiments, mice were ventilated in the absence and presence of autophagy inhibitors 3-methyladenine (15 mg/kg ip) or trichostatin A (1 mg/kg ip). Mechanical ventilation with a high tidal volume caused rapid (within minutes) activation of autophagy in the lung. Conventional transmission electron microscopic examination of lung sections showed that mechanical ventilation-induced autophagy activation mainly occurred in lung macrophages. Autophagy activation in the lungs during mechanical ventilation was dramatically attenuated in alveolar macrophage-depleted mice. Selective silencing of autophagy-related protein 5 in lung macrophages abolished mechanical ventilation-induced nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome activation and lung inflammatory injury. Pharmacological inhibition of autophagy also significantly attenuated the inflammatory responses caused by lung hyperinflation. The activation of autophagy in macrophages mediates early lung inflammation during mechanical ventilation via NLRP3 inflammasome signaling. Inhibition of autophagy activation in lung macrophages may therefore provide a novel and promising strategy for the prevention and treatment of ventilator-induced lung injury. PMID:24838752

  5. Minute ventilation of cyclists, car and bus passengers: an experimental study.

    PubMed

    Zuurbier, Moniek; Hoek, Gerard; van den Hazel, Peter; Brunekreef, Bert

    2009-10-27

    Differences in minute ventilation between cyclists, pedestrians and other commuters influence inhaled doses of air pollution. This study estimates minute ventilation of cyclists, car and bus passengers, as part of a study on health effects of commuters' exposure to air pollutants. Thirty-four participants performed a submaximal test on a bicycle ergometer, during which heart rate and minute ventilation were measured simultaneously at increasing cycling intensity. Individual regression equations were calculated between heart rate and the natural log of minute ventilation. Heart rates were recorded during 280 two hour trips by bicycle, bus and car and were calculated into minute ventilation levels using the individual regression coefficients. Minute ventilation during bicycle rides were on average 2.1 times higher than in the car (individual range from 1.3 to 5.3) and 2.0 times higher than in the bus (individual range from 1.3 to 5.1). The ratio of minute ventilation of cycling compared to travelling by bus or car was higher in women than in men. Substantial differences in regression equations were found between individuals. The use of individual regression equations instead of average regression equations resulted in substantially better predictions of individual minute ventilations. The comparability of the gender-specific overall regression equations linking heart rate and minute ventilation with one previous American study, supports that for studies on the group level overall equations can be used. For estimating individual doses, the use of individual regression coefficients provides more precise data. Minute ventilation levels of cyclists are on average two times higher than of bus and car passengers, consistent with the ratio found in one small previous study of young adults. The study illustrates the importance of inclusion of minute ventilation data in comparing air pollution doses between different modes of transport.

  6. Ventilator use by emergency medical services during 911 calls in the United States.

    PubMed

    El Sayed, Mazen; Tamim, Hani; Mailhac, Aurelie; N Clay, Mann

    2018-05-01

    Emergency and transport ventilators use in the prehospital field is not well described. This study examines trends of ventilator use by EMS agencies during 911 calls in the United States and identifies factors associated with this use. This retrospective study used four consecutive releases of the US National Emergency Medical Services Information System (NEMSIS) public research dataset (2011-2014) to describe scene EMS activations (911 calls) with and without reported ventilator use. Ventilator use was reported in 260,663 out of 28,221,321 EMS 911 scene activations (0.9%). Patients with ventilator use were older (mean age 67±18years), nearly half were males (49.2%), mostly in urban areas (80.2%) and cared for by advanced life support (ALS) EMS services (89.5%). CPAP mode of ventilation was most common (71.6%). "Breathing problem" was the most common dispatch complaint for EMS activations with ventilator use (63.9%). Common provider impression categories included "respiratory distress" (72.5%), "cardiac rhythm disturbance" (4.6%), "altered level of consciousness" (4.3%) and "cardiac arrest"(4.0%). Ventilator use was consistently higher at the Specialty Care Transport (SCT) and Air Medical Transport (AMT) service levels and increased over the study period for both suburban and rural EMS activations. Significant factors for ventilator use included demographic characteristics, EMS agency type, specific complaints, provider's primary impressions and condition codes. Providers at different EMS levels use ventilators during 911 scene calls in the US. Training of prehospital providers on ventilation technology is needed. The benefit and effectiveness of this intervention remain to be assessed. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Artificial humidification for the mechanically ventilated patient.

    PubMed

    Selvaraj, N

    Caring for patients who are mechanically ventilated poses many challenges for critical care nurses. It is important to humidify the patient's airways artificially to prevent complications such as ventilator-associated pneumonia. There is no gold standard to determine which type of humidification is best for patients who are artificially ventilated. This article provides an overview of commonly used artificial humidification for mechanically ventilated patients and discusses nurses' responsibilities in caring for patients receiving artificial humidification.

  8. Development of spatial-temporal ventilation heterogeneity and probability analysis tools for hyperpolarized 3He magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Choy, S.; Ahmed, H.; Wheatley, A.; McCormack, D. G.; Parraga, G.

    2010-03-01

    We developed image analysis tools to evaluate spatial and temporal 3He magnetic resonance imaging (MRI) ventilation in asthma and cystic fibrosis. We also developed temporal ventilation probability maps to provide a way to describe and quantify ventilation heterogeneity over time, as a way to test respiratory exacerbations or treatment predictions and to provide a discrete probability measurement of 3He ventilation defect persistence.

  9. Mask Ventilation during Induction of General Anesthesia: Influences of Obstructive Sleep Apnea.

    PubMed

    Sato, Shin; Hasegawa, Makoto; Okuyama, Megumi; Okazaki, Junko; Kitamura, Yuji; Sato, Yumi; Ishikawa, Teruhiko; Sato, Yasunori; Isono, Shiroh

    2017-01-01

    Depending on upper airway patency during anesthesia induction, tidal volume achieved by mask ventilation may vary. In 80 adult patients undergoing general anesthesia, the authors tested a hypothesis that tidal volume during mask ventilation is smaller in patients with sleep-disordered breathing priorly defined as apnea hypopnea index greater than 5 per hour. One-hand mask ventilation with a constant ventilator setting (pressure-controlled ventilation) was started 20 s after injection of rocuronium and maintained for 1 min during anesthesia induction. Mask ventilation efficiency was assessed by the breath number needed to initially exceed 5 ml/kg ideal body weight of expiratory tidal volume (primary outcome) and tidal volumes (secondary outcomes) during initial 15 breaths (UMIN000012494). Tidal volume progressively increased by more than 70% in 1 min and did not differ between sleep-disordered breathing (n = 42) and non-sleep-disordered breathing (n = 38) patients. In post hoc subgroup analyses, the primary outcome breath number (mean [95% CI], 5.7 [4.1 to 7.3] vs. 1.7 [0.2 to 3.2] breath; P = 0.001) and mean tidal volume (6.5 [4.6 to 8.3] vs. 9.6 [7.7 to 11.4] ml/kg ideal body weight; P = 0.032) were significantly smaller in 20 sleep-disordered breathing patients with higher apnea hypopnea index (median [25th to 75th percentile]: 21.7 [17.6 to 31] per hour) than in 20 non-sleep disordered breathing subjects with lower apnea hypopnea index (1.0 [0.3 to 1.5] per hour). Obesity and occurrence of expiratory flow limitation during one-hand mask ventilation independently explained the reduction of efficiency of mask ventilation, while the use of two hands effectively normalized inefficient mask ventilation during one-hand mask ventilation. One-hand mask ventilation is difficult in patients with obesity and severe sleep-disordered breathing particularly when expiratory flow limitation occurs during mask ventilation.

  10. Daily Goals Formulation and Enhanced Visualization of Mechanical Ventilation Variance Improves Mechanical Ventilation Score.

    PubMed

    Walsh, Brian K; Smallwood, Craig; Rettig, Jordan; Kacmarek, Robert M; Thompson, John; Arnold, John H

    2017-03-01

    The systematic implementation of evidence-based practice through the use of guidelines, checklists, and protocols mitigates the risks associated with mechanical ventilation, yet variation in practice remains prevalent. Recent advances in software and hardware have allowed for the development and deployment of an enhanced visualization tool that identifies mechanical ventilation goal variance. Our aim was to assess the utility of daily goal establishment and a computer-aided visualization of variance. This study was composed of 3 phases: a retrospective observational phase (baseline) followed by 2 prospective sequential interventions. Phase I intervention comprised daily goal establishment of mechanical ventilation. Phase II intervention was the setting and monitoring of daily goals of mechanical ventilation with a web-based data visualization system (T3). A single score of mechanical ventilation was developed to evaluate the outcome. The baseline phase evaluated 130 subjects, phase I enrolled 31 subjects, and phase II enrolled 36 subjects. There were no differences in demographic characteristics between cohorts. A total of 171 verbalizations of goals of mechanical ventilation were completed in phase I. The use of T3 increased by 87% from phase I. Mechanical ventilation score improved by 8.4% in phase I and 11.3% in phase II from baseline ( P = .032). The largest effect was in the low risk V T category, with a 40.3% improvement from baseline in phase I, which was maintained at 39% improvement from baseline in phase II ( P = .01). mechanical ventilation score was 9% higher on average in those who survived. Daily goal formation and computer-enhanced visualization of mechanical ventilation variance were associated with an improvement in goal attainment by evidence of an improved mechanical ventilation score. Further research is needed to determine whether improvements in mechanical ventilation score through a targeted, process-oriented intervention will lead to improved patient outcomes. (ClinicalTrials.gov registration NCT02184208.). Copyright © 2017 by Daedalus Enterprises.

  11. The Society for Translational Medicine: clinical practice guidelines for mechanical ventilation management for patients undergoing lobectomy.

    PubMed

    Gao, Shugeng; Zhang, Zhongheng; Brunelli, Alessandro; Chen, Chang; Chen, Chun; Chen, Gang; Chen, Haiquan; Chen, Jin-Shing; Cassivi, Stephen; Chai, Ying; Downs, John B; Fang, Wentao; Fu, Xiangning; Garutti, Martínez I; He, Jianxing; He, Jie; Hu, Jian; Huang, Yunchao; Jiang, Gening; Jiang, Hongjing; Jiang, Zhongmin; Li, Danqing; Li, Gaofeng; Li, Hui; Li, Qiang; Li, Xiaofei; Li, Yin; Li, Zhijun; Liu, Chia-Chuan; Liu, Deruo; Liu, Lunxu; Liu, Yongyi; Ma, Haitao; Mao, Weimin; Mao, Yousheng; Mou, Juwei; Ng, Calvin Sze Hang; Petersen, René H; Qiao, Guibin; Rocco, Gaetano; Ruffini, Erico; Tan, Lijie; Tan, Qunyou; Tong, Tang; Wang, Haidong; Wang, Qun; Wang, Ruwen; Wang, Shumin; Xie, Deyao; Xue, Qi; Xue, Tao; Xu, Lin; Xu, Shidong; Xu, Songtao; Yan, Tiansheng; Yu, Fenglei; Yu, Zhentao; Zhang, Chunfang; Zhang, Lanjun; Zhang, Tao; Zhang, Xun; Zhao, Xiaojing; Zhao, Xuewei; Zhi, Xiuyi; Zhou, Qinghua

    2017-09-01

    Patients undergoing lobectomy are at significantly increased risk of lung injury. One-lung ventilation is the most commonly used technique to maintain ventilation and oxygenation during the operation. It is a challenge to choose an appropriate mechanical ventilation strategy to minimize the lung injury and other adverse clinical outcomes. In order to understand the available evidence, a systematic review was conducted including the following topics: (I) protective ventilation (PV); (II) mode of mechanical ventilation [e.g., volume controlled (VCV) versus pressure controlled (PCV)]; (III) use of therapeutic hypercapnia; (IV) use of alveolar recruitment (open-lung) strategy; (V) pre-and post-operative application of positive end expiratory pressure (PEEP); (VI) Inspired Oxygen concentration; (VII) Non-intubated thoracoscopic lobectomy; and (VIII) adjuvant pharmacologic options. The recommendations of class II are non-intubated thoracoscopic lobectomy may be an alternative to conventional one-lung ventilation in selected patients. The recommendations of class IIa are: (I) Therapeutic hypercapnia to maintain a partial pressure of carbon dioxide at 50-70 mmHg is reasonable for patients undergoing pulmonary lobectomy with one-lung ventilation; (II) PV with a tidal volume of 6 mL/kg and PEEP of 5 cmH 2 O are reasonable methods, based on current evidence; (III) alveolar recruitment [open lung ventilation (OLV)] may be beneficial in patients undergoing lobectomy with one-lung ventilation; (IV) PCV is recommended over VCV for patients undergoing lung resection; (V) pre- and post-operative CPAP can improve short-term oxygenation in patients undergoing lobectomy with one-lung ventilation; (VI) controlled mechanical ventilation with I:E ratio of 1:1 is reasonable in patients undergoing one-lung ventilation; (VII) use of lowest inspired oxygen concentration to maintain satisfactory arterial oxygen saturation is reasonable based on physiologic principles; (VIII) Adjuvant drugs such as nebulized budesonide, intravenous sivelestat and ulinastatin are reasonable and can be used to attenuate inflammatory response.

  12. Modes of mechanical ventilation for the operating room.

    PubMed

    Ball, Lorenzo; Dameri, Maddalena; Pelosi, Paolo

    2015-09-01

    Most patients undergoing surgical procedures need to be mechanically ventilated, because of the impact of several drugs administered at induction and during maintenance of general anaesthesia on respiratory function. Optimization of intraoperative mechanical ventilation can reduce the incidence of post-operative pulmonary complications and improve the patient's outcome. Preoxygenation at induction of general anaesthesia prolongs the time window for safe intubation, reducing the risk of hypoxia and overweighs the potential risk of reabsorption atelectasis. Non-invasive positive pressure ventilation delivered through different interfaces should be considered at the induction of anaesthesia morbidly obese patients. Anaesthesia ventilators are becoming increasingly sophisticated, integrating many functions that were once exclusive to intensive care. Modern anaesthesia machines provide high performances in delivering the desired volumes and pressures accurately and precisely, including assisted ventilation modes. Therefore, the physicians should be familiar with the potential and pitfalls of the most commonly used intraoperative ventilation modes: volume-controlled, pressure-controlled, dual-controlled and assisted ventilation. Although there is no clear evidence to support the advantage of any one of these ventilation modes over the others, protective mechanical ventilation with low tidal volume and low levels of positive end-expiratory pressure (PEEP) should be considered in patients undergoing surgery. The target tidal volume should be calculated based on the predicted or ideal body weight rather than on the actual body weight. To optimize ventilation monitoring, anaesthesia machines should include end-inspiratory and end-expiratory pause as well as flow-volume loop curves. The routine administration of high PEEP levels should be avoided, as this may lead to haemodynamic impairment and fluid overload. Higher PEEP might be considered during surgery longer than 3 h, laparoscopy in the Trendelenburg position and in patients with body mass index >35 kg/m(2). Large randomized trials are warranted to identify subgroups of patients and the type of surgery that can potentially benefit from specific ventilation modes or ventilation settings. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. The Society for Translational Medicine: clinical practice guidelines for mechanical ventilation management for patients undergoing lobectomy

    PubMed Central

    Zhang, Zhongheng; Brunelli, Alessandro; Chen, Chang; Chen, Chun; Chen, Gang; Chen, Haiquan; Chen, Jin-Shing; Cassivi, Stephen; Chai, Ying; Downs, John B.; Fang, Wentao; Fu, Xiangning; Garutti, Martínez I.; He, Jianxing; Hu, Jian; Huang, Yunchao; Jiang, Gening; Jiang, Hongjing; Jiang, Zhongmin; Li, Danqing; Li, Gaofeng; Li, Hui; Li, Qiang; Li, Xiaofei; Li, Yin; Li, Zhijun; Liu, Chia-Chuan; Liu, Deruo; Liu, Lunxu; Liu, Yongyi; Ma, Haitao; Mao, Weimin; Mao, Yousheng; Mou, Juwei; Ng, Calvin Sze Hang; Petersen, René H.; Qiao, Guibin; Rocco, Gaetano; Ruffini, Erico; Tan, Lijie; Tan, Qunyou; Tong, Tang; Wang, Haidong; Wang, Qun; Wang, Ruwen; Wang, Shumin; Xie, Deyao; Xue, Qi; Xue, Tao; Xu, Lin; Xu, Shidong; Xu, Songtao; Yan, Tiansheng; Yu, Fenglei; Yu, Zhentao; Zhang, Chunfang; Zhang, Lanjun; Zhang, Tao; Zhang, Xun; Zhao, Xiaojing; Zhao, Xuewei; Zhi, Xiuyi; Zhou, Qinghua

    2017-01-01

    Patients undergoing lobectomy are at significantly increased risk of lung injury. One-lung ventilation is the most commonly used technique to maintain ventilation and oxygenation during the operation. It is a challenge to choose an appropriate mechanical ventilation strategy to minimize the lung injury and other adverse clinical outcomes. In order to understand the available evidence, a systematic review was conducted including the following topics: (I) protective ventilation (PV); (II) mode of mechanical ventilation [e.g., volume controlled (VCV) versus pressure controlled (PCV)]; (III) use of therapeutic hypercapnia; (IV) use of alveolar recruitment (open-lung) strategy; (V) pre-and post-operative application of positive end expiratory pressure (PEEP); (VI) Inspired Oxygen concentration; (VII) Non-intubated thoracoscopic lobectomy; and (VIII) adjuvant pharmacologic options. The recommendations of class II are non-intubated thoracoscopic lobectomy may be an alternative to conventional one-lung ventilation in selected patients. The recommendations of class IIa are: (I) Therapeutic hypercapnia to maintain a partial pressure of carbon dioxide at 50–70 mmHg is reasonable for patients undergoing pulmonary lobectomy with one-lung ventilation; (II) PV with a tidal volume of 6 mL/kg and PEEP of 5 cmH2O are reasonable methods, based on current evidence; (III) alveolar recruitment [open lung ventilation (OLV)] may be beneficial in patients undergoing lobectomy with one-lung ventilation; (IV) PCV is recommended over VCV for patients undergoing lung resection; (V) pre- and post-operative CPAP can improve short-term oxygenation in patients undergoing lobectomy with one-lung ventilation; (VI) controlled mechanical ventilation with I:E ratio of 1:1 is reasonable in patients undergoing one-lung ventilation; (VII) use of lowest inspired oxygen concentration to maintain satisfactory arterial oxygen saturation is reasonable based on physiologic principles; (VIII) Adjuvant drugs such as nebulized budesonide, intravenous sivelestat and ulinastatin are reasonable and can be used to attenuate inflammatory response. PMID:29221302

  14. Spontaneous breathing during lung-protective ventilation in an experimental acute lung injury model: high transpulmonary pressure associated with strong spontaneous breathing effort may worsen lung injury.

    PubMed

    Yoshida, Takeshi; Uchiyama, Akinori; Matsuura, Nariaki; Mashimo, Takashi; Fujino, Yuji

    2012-05-01

    We investigated whether potentially injurious transpulmonary pressure could be generated by strong spontaneous breathing and exacerbate lung injury even when plateau pressure is limited to <30 cm H2O. Prospective, randomized, animal study. University animal research laboratory. Thirty-two New Zealand White rabbits. Lavage-injured rabbits were randomly allocated to four groups to receive low or moderate tidal volume ventilation, each combined with weak or strong spontaneous breathing effort. Inspiratory pressure for low tidal volume ventilation was set at 10 cm H2O and tidal volume at 6 mL/kg. For moderate tidal volume ventilation, the values were 20 cm H2O and 7-9 mL/kg. The groups were: low tidal volume ventilation+spontaneous breathingweak, low tidal volume ventilation+spontaneous breathingstrong, moderate tidal volume ventilation+spontaneous breathingweak, and moderate tidal volume ventilation+spontaneous breathingstrong. Each group had the same settings for positive end-expiratory pressure of 8 cm H2O. Respiratory variables were measured every 60 mins. Distribution of lung aeration and alveolar collapse were histologically evaluated. Low tidal volume ventilation+spontaneous breathingstrong showed the most favorable oxygenation and compliance of respiratory system, and the best lung aeration. By contrast, in moderate tidal volume ventilation+spontaneous breathingstrong, the greatest atelectasis with numerous neutrophils was observed. While we applied settings to maintain plateau pressure at <30 cm H2O in all groups, in moderate tidal volume ventilation+spontaneous breathingstrong, transpulmonary pressure rose >33 cm H2O. Both minute ventilation and respiratory rate were higher in the strong spontaneous breathing groups. Even when plateau pressure is limited to <30 cm H2O, combined with increased respiratory rate and tidal volume, high transpulmonary pressure generated by strong spontaneous breathing effort can worsen lung injury. When spontaneous breathing is preserved during mechanical ventilation, transpulmonary pressure and tidal volume should be strictly controlled to prevent further lung injury.

  15. Using Hyperpolarized 129Xe MRI to Quantify the Pulmonary Ventilation Distribution

    PubMed Central

    He, Mu; Driehuys, Bastiaan; Que, Loretta G.; Huang, Yuh-Chin T.

    2017-01-01

    Background Ventilation heterogeneity is impossible to detect with spirometry. Alternatively, pulmonary ventilation can be imaged 3-dimensionally using inhaled 129Xe MRI. To date such images have been quantified primarily based on ventilation defects. Here, we introduce a robust means to transform 129Xe MRI scans such that the underlying ventilation distribution and its heterogeneity can be quantified. Methods Quantitative 129Xe ventilation MRI was conducted in 12 younger (24.7±5.2 yrs), and 10 older (62.2±7.2 yrs) healthy individuals, as well as 9 younger (25.9±6.4 yrs) and 10 older (63.2±6.1 yrs) asthmatics. The younger healthy population was used to establish a reference ventilation distribution and thresholds for 6 intensity bins. These were used to display and quantify regions of ventilation defect (VDR), low ventilation (LVR) and high ventilation (HVR). Results The ventilation distribution in young subjects was roughly Gaussian with a mean and SD of 0.52±0.18, resulting in VDR=2.1±1.3%, LVR=15.6±5.4% and HVR=17.4±3.1%. Older healthy volunteers exhibited a significantly right-skewed distribution (0.46±0.20, p=0.034), resulting in significantly increased VDR (7.0±4.8%, p=0.008) and LVR (24.5±11.5%, p=0.025). In the asthmatics, VDR and LVR increased in the older population, and HVR was significantly reduced (13.5±4.6% vs 18.9±4.5%, p=0.009). Quantitative 129Xe MRI also revealed different ventilation distribution patterns in response to albuterol in two asthmatics with normal FEV1. Conclusions Quantitative 129Xe MRI provides a robust and objective means to display and quantify the pulmonary ventilation distribution, even in subjects who have airway function impairment not appreciated by spirometry. PMID:27617823

  16. Cost of treating ventilator-associated pneumonia post cardiac surgery in the National Health Service: Results from a propensity-matched cohort study.

    PubMed

    Luckraz, Heyman; Manga, Na'ngono; Senanayake, Eshan L; Abdelaziz, Mahmoud; Gopal, Shameer; Charman, Susan C; Giri, Ramesh; Oppong, Raymond; Andronis, Lazaros

    2018-05-01

    Ventilator-associated pneumonia is associated with significant morbidity, mortality and healthcare costs. Most of the cost data that are available relate to general intensive care patients in privately remunerated institutions. This study assessed the cost of managing ventilator-associated pneumonia in a cardiac intensive care unit in the National Health Service in the United Kingdom. Propensity-matched study of prospectively collected data from the cardiac surgical database between April 2011 and December 2014 in all patients undergoing cardiac surgery (n = 3416). Patients who were diagnosed as developing ventilator-associated pneumonia, as per the surveillance definition for ventilator-associated pneumonia (n = 338), were propensity score matched with those who did not (n = 338). Costs of treating post-op cardiac surgery patients in intensive care and cost difference if ventilator-associated pneumonia occurred based on Healthcare Resource Group categories were assessed. Secondary outcomes included differences in morbidity, mortality and cardiac intensive care unit and in-hospital length of stay. There were no significant differences in the pre-operative characteristics or procedures between the groups. Ventilator-associated pneumonia developed in 10% of post-cardiac surgery patients. Post-operatively, the ventilator-associated pneumonia group required longer ventilation (p < 0.01), more respiratory support, longer cardiac intensive care unit (8 vs 3, p < 0.001) and in-hospital stay (16 vs 9) days. The overall cost for post-operative recovery after cardiac surgery for ventilator-associated pneumonia patients was £15,124 compared to £6295 for non-ventilator-associated pneumonia (p < 0.01). The additional cost of treating patients with ventilator-associated pneumonia was £8829. Ventilator-associated pneumonia was associated with significant morbidity to the patients, generating significant costs. This cost was nearer to the lower end for the cost for general intensive care unit patients in privately reimbursed systems.

  17. Protective isolation in single-bed rooms: studies in a modified hospital ward

    PubMed Central

    Ayliffe, G. A. J.; Collins, B. J.; Lowbury, E. J. L.; Wall, Mary

    1971-01-01

    Studies were made in a modified hospital ward containing 19 beds, 14 of them in the open ward, one in a window-ventilated side-room, two in rooms with partial-recirculation ventilators giving 7-10 air changes per hour, and two in self-contained isolation suites with plenum ventilation (20 air changes per hour), ultra-violet (UV) barriers at doorways and airlocks. Preliminary tests with aerosols of tracer bacteria showed that few bacteria entered the plenum or recirculation-ventilated rooms. Bacteria released inside mechanically ventilated cubicles escaped into the corridor, but this transfer was reduced by the presence of an airlock. UV barriers at the entrance to the airlock and the cubicle reduced the transfer of bacteria from cubicle to corridor. During a period of 4 years while the ward was in use for surgical and gynaecological patients, the incidence of post-operative sepsis and colonization of wounds by multiple-resistant Staphylococcus aureus was lower (though not significantly lower) in the plenum-ventilated rooms than in the open ward, the recirculator-ventilated cubicles and the window-ventilated cubicles. Nasal acquisition of multiple-resistant Staph. aureus was significantly less common in the plenum-ventilated than in the recirculator-ventilated cubicles and in the other areas. Mean counts of bacteria on settle-plates were significantly lower in the plenum-ventilated cubicles than in the other areas; mean settle-plate counts in the recirculator-ventilated cubicles were significantly lower than in the open ward and in the window-ventilated side-room; similar results were shown by slit-sampling of air. Mean settle-plate counts were significantly lower in all areas when the ward was occupied by female patients. Staph. aureus was rarely carried by air from plenum-ventilated or other cubicles to the open ward, or from the open ward to the cubicles; though staphylococci were transferred from one floor area to another, they did not appear to be redispersed into the air in sufficient numbers to infect the patients. Ultra-violet irradiation caused a significant reduction in the total and staphylococcal counts from the floors of airlocks, and a significant reduction of total counts in the air. PMID:5289715

  18. Evaluating the effects of protective ventilation on organ-specific cytokine production in porcine experimental postoperative sepsis.

    PubMed

    Sperber, Jesper; Lipcsey, Miklós; Larsson, Anders; Larsson, Anders; Sjölin, Jan; Castegren, Markus

    2015-05-10

    Protective ventilation with lower tidal volume (VT) and higher positive end-expiratory pressure (PEEP) reduces the negative additive effects of mechanical ventilation during systemic inflammatory response syndrome. We hypothesised that protective ventilation during surgery would affect the organ-specific immune response in an experimental animal model of endotoxin-induced sepsis-like syndrome. 30 pigs were laparotomised for 2 hours (h), after which a continuous endotoxin infusion was started at 0.25 micrograms × kg(-1) × h(-1) for 5 h. Catheters were placed in the carotid artery, hepatic vein, portal vein and jugular bulb. Animals were randomised to two protective ventilation groups (n = 10 each): one group was ventilated with VT 6 mL × kg(-1) during the whole experiment while the other group was ventilated during the surgical phase with VT of 10 mL × kg(-1). In both groups PEEP was 5 cmH2O during surgery and increased to 10 cmH2O at the start of endotoxin infusion. A control group (n = 10) was ventilated with VT of 10 mL × kg(-1) and PEEP 5 cm H20 throughout the experiment. In four sample locations we a) simultaneously compared cytokine levels, b) studied the effect of protective ventilation initiated before and during endotoxemia and c) evaluated protective ventilation on organ-specific cytokine levels. TNF-alpha levels were highest in the hepatic vein, IL-6 levels highest in the artery and jugular bulb and IL-10 levels lowest in the artery. Protective ventilation initiated before and during endotoxemia did not differ in organ-specific cytokine levels. Protective ventilation led to lower levels of TNF-alpha in the hepatic vein compared with the control group, whereas no significant differences were seen in the artery, portal vein or jugular bulb. Variation between organs in cytokine output was observed during experimental sepsis. We see no implication from cytokine levels for initiating protective ventilation before endotoxemia. However, during endotoxemia protective ventilation attenuates hepatic inflammatory cytokine output contributing to a reduced total inflammatory burden.

  19. Occupational exposure to nitrous oxide - the role of scavenging and ventilation systems in reducing the exposure level in operating rooms.

    PubMed

    Krajewski, Wojciech; Kucharska, Malgorzata; Wesolowski, Wiktor; Stetkiewicz, Jan; Wronska-Nofer, Teresa

    2007-03-01

    The aim of this study was to assess the level of occupational exposure to nitrous oxide (N(2)O) in operating rooms (ORs), as related to different ventilation and scavenging systems used to remove waste anaesthetic gases from the work environment. The monitoring of N(2)O in the air covered 35 ORs in 10 hospitals equipped with different systems for ventilation and anaesthetic scavenging. The examined systems included: natural ventilation with supplementary fresh air provided by a pressure ventilation system (up to 6 air changes/h); pressure and exhaust ventilation systems equipped with ventilation units supplying fresh air to and discharging contaminated air outside the working area (more than 10 air changes/h); complete air-conditioning system with laminar air flow (more than 15 air changes/h). The measurements were carried out during surgical procedures (general anaesthesia induced intravenously and maintained with inhaled N(2)O and sevofluran delivered through cuffed endotracheal tubes) with connected or disconnected air scavenging. Air was collected from the breathing zone of operating personnel continuously through the whole time of anaesthesia to Tedlar((R)) bags, and N(2)O concentrations in air samples were analyzed by adsorption gas chromatography/mass spectrometry. N(2)O levels in excess of the occupational exposure limit (OEL) value of 180mg/m(3) were registered in all ORs equipped with ventilation systems alone. The OEL value was exceeded several times in rooms with natural ventilation plus supplementary pressure ventilations and twice or less in those with pressure/exhaust ventilation systems or air conditioning. N(2)O levels below or within the OEL value were observed in rooms where the system of air conditioning or pressure/exhaust ventilation was combined with scavenging systems. Systems combining natural/pressure ventilation with scavenging were inadequate to maintain N(2)O concentration below the OEL value. Air conditioning and an efficient pressure/exhaust ventilation (above 12 air exchanges/h) together with efficient active scavenging systems are sufficient to sustain N(2)O exposure in ORs at levels below or within the OEL value of 180mg/m(3).

  20. Smart ventilation energy and indoor air quality performance in residential buildings: A review

    DOE PAGES

    Guyot, Gaelle; Sherman, Max H.; Walker, Iain S.

    2017-12-30

    To better address energy and indoor air quality issues, ventilation needs to become smarter. A key smart ventilation concept is to use controls to ventilate more at times it provides either an energy or indoor air quality (IAQ) advantage (or both) and less when it provides a disadvantage. A favorable context exists in many countries to include some of the existing smart ventilation strategies in codes and standards. As a result, demand-controlled ventilation (DCV) systems are widely and easily available on the market, with more than 20 DCV systems approved and available in countries such as Belgium, France and themore » Netherlands. This paper provides a literature review on smart ventilation used in residential buildings, based on energy and indoor air quality performance. This meta-analysis includes 38 studies of various smart ventilation systems with control based on CO 2, humidity, combined CO 2 and total volatile organic compounds (TVOC), occupancy, or outdoor temperature. In conclusion, these studies show that ventilation energy savings up to 60% can be obtained without compromising IAQ, even sometimes improving it. However, the meta-analysis included some less than favorable results, with 26% energy overconsumption in some cases.« less

  1. New modes of assisted mechanical ventilation.

    PubMed

    Suarez-Sipmann, F

    2014-05-01

    Recent major advances in mechanical ventilation have resulted in new exciting modes of assisted ventilation. Compared to traditional ventilation modes such as assisted-controlled ventilation or pressure support ventilation, these new modes offer a number of physiological advantages derived from the improved patient control over the ventilator. By implementing advanced closed-loop control systems and using information on lung mechanics, respiratory muscle function and respiratory drive, these modes are specifically designed to improve patient-ventilator synchrony and reduce the work of breathing. Depending on their specific operational characteristics, these modes can assist spontaneous breathing efforts synchronically in time and magnitude, adapt to changing patient demands, implement automated weaning protocols, and introduce a more physiological variability in the breathing pattern. Clinicians have now the possibility to individualize and optimize ventilatory assistance during the complex transition from fully controlled to spontaneous assisted ventilation. The growing evidence of the physiological and clinical benefits of these new modes is favoring their progressive introduction into clinical practice. Future clinical trials should improve our understanding of these modes and help determine whether the claimed benefits result in better outcomes. Copyright © 2013 Elsevier España, S.L. and SEMICYUC. All rights reserved.

  2. Lung-protective ventilation in abdominal surgery.

    PubMed

    Futier, Emmanuel; Jaber, Samir

    2014-08-01

    To provide the most recent and relevant clinical evidence regarding the use of prophylactic lung-protective mechanical ventilation in abdominal surgery. Evidence is accumulating, suggesting an association between intraoperative mechanical ventilation strategy and postoperative pulmonary complications in patients undergoing abdominal surgery. Nonprotective ventilator settings, especially high tidal volume (>10-12 ml/kg), very low level of positive end-expiratory pressure (PEEP, <5 cm H2O), or no PEEP, may cause alveolar overdistension and repetitive tidal recruitment leading to ventilator-associated lung injury in patients with healthy lungs. Stimulated by the previous findings in patients with acute respiratory distress syndrome, the use of lower tidal volume ventilation is becoming increasingly more common in the operating room. However, lowering tidal volume, though important, is only part of the overall multifaceted approach of lung-protective mechanical ventilation. Recent data provide compelling evidence that prophylactic lung-protective mechanical ventilation using lower tidal volume (6-8 ml/kg of predicted body weight), moderate PEEP (6-8 cm H2O), and recruitment maneuvers is associated with improved functional or physiological and clinical postoperative outcome in patients undergoing abdominal surgery. The use of prophylactic lung-protective ventilation can help in improving the postoperative outcome.

  3. Controlled invasive mechanical ventilation strategies in obese patients undergoing surgery.

    PubMed

    Maia, Lígia de Albuquerque; Silva, Pedro Leme; Pelosi, Paolo; Rocco, Patricia Rieken Macedo

    2017-06-01

    The obesity prevalence is increasing in surgical population. As the number of obese surgical patients increases, so does the demand for mechanical ventilation. Nevertheless, ventilatory strategies in this population are challenging, since obesity results in pathophysiological changes in respiratory function. Areas covered: We reviewed the impact of obesity on respiratory system and the effects of controlled invasive mechanical ventilation strategies in obese patients undergoing surgery. To date, there is no consensus regarding the optimal invasive mechanical ventilation strategy for obese surgical patients, and no evidence that possible intraoperative beneficial effects on oxygenation and mechanics translate into better postoperative pulmonary function or improved outcomes. Expert commentary: Before determining the ideal intraoperative ventilation strategy, it is important to analyze the pathophysiology and comorbidities of each obese patient. Protective ventilation with low tidal volume, driving pressure, energy, and mechanical power should be employed during surgery; however, further studies are required to clarify the most effective ventilation strategies, such as the optimal positive end-expiratory pressure and whether recruitment maneuvers minimize lung injury. In this context, an ongoing trial of intraoperative ventilation in obese patients (PROBESE) should help determine the mechanical ventilation strategy that best improves clinical outcome in patients with body mass index≥35kg/m 2 .

  4. Smart ventilation energy and indoor air quality performance in residential buildings: A review

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Guyot, Gaelle; Sherman, Max H.; Walker, Iain S.

    To better address energy and indoor air quality issues, ventilation needs to become smarter. A key smart ventilation concept is to use controls to ventilate more at times it provides either an energy or indoor air quality (IAQ) advantage (or both) and less when it provides a disadvantage. A favorable context exists in many countries to include some of the existing smart ventilation strategies in codes and standards. As a result, demand-controlled ventilation (DCV) systems are widely and easily available on the market, with more than 20 DCV systems approved and available in countries such as Belgium, France and themore » Netherlands. This paper provides a literature review on smart ventilation used in residential buildings, based on energy and indoor air quality performance. This meta-analysis includes 38 studies of various smart ventilation systems with control based on CO 2, humidity, combined CO 2 and total volatile organic compounds (TVOC), occupancy, or outdoor temperature. In conclusion, these studies show that ventilation energy savings up to 60% can be obtained without compromising IAQ, even sometimes improving it. However, the meta-analysis included some less than favorable results, with 26% energy overconsumption in some cases.« less

  5. [Intraoperative monitoring in artificial respiration of premature and newborn infants. I. Monitoring of respiratory parameters and alveolar ventilation].

    PubMed

    Lenz, G; Heipertz, W; Leidig, E; Madee, S

    1986-06-01

    Monitoring of ventilation serves to ensure adequate alveolar ventilation and arterial oxygenation, and to avoid pulmonary damage due to mechanical ventilation. Basic clinical monitoring, i.e., inspection, auscultation (including precordial or oesophageal stethoscope) and monitoring of heart rate and blood pressure, is mandatory. Mechanical ventilation is monitored by ventilation pressures (peak pressure, plateau pressure and endexpiratory pressure), ventilation volumes (measured at the in/expiratory valve of the respirator and by hot-wire anemometry at the tube connector), ventilation rate, and inspiratory oxygen concentration (FiO2). Alveolar ventilation should be continuously and indirectly recorded by capnometry (pECO2) and by measurement of transcutaneous pCO2 (tcpCO2), whereas oxygenation is determined via measurement of transcutaneous pO2 (tcpO2). Invasive monitoring of gas exchange is essential in prolonged or intrathoracic interventions as well as in neonates with cardiopulmonary problems. paCO2 may be estimated by capillary or venous blood gas analysis; arterial blood gas analysis is required for exact determination of paCO2 as well as arteriocutaneous pCO2 (atcDCO2) and arterio-end-expiratory (aEDCO2) gradients.

  6. Javanese House’s Roof (Joglo) with the Opening as a Cooling Energy Provider

    NASA Astrophysics Data System (ADS)

    Pranoto S, M.

    2018-01-01

    Natural ventilation and air movement could be considered under the heading structural controls as it does not rely on any form of energy supply or mechanical installation but due to its importance for human comfort, it deserves a separate section. Air infiltration can destroy the performance of ventilation systems. Good ventilation design combined with optimum air tightness is needed to ensure energy efficient ventilation. Ultimately, ventilation needs depend on occupancy pattern and building use. A full cost and energy analysis is therefore needed to select an optimum ventilation strategy.The contains of paper is about the element of Javanese house (the roof) as the element of natural ventilation and a cooling energy provider. In this research, The Computational Fluid Dynamics Program, is used to draw and analysis. That tool can be track the pattern and the direction of movement of air also the air velocity in the object of ventilation of the roof Javanese house based. Finally, the ventilation of the roof of this Javanese house can add the velocity of air at indoor, average 0.4 m/s and give the effect of cooling, average 0.7°C.

  7. WE-AB-BRA-06: 4DCT-Ventilation: A Novel Imaging Modality for Thoracic Surgical Evaluation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Vinogradskiy, Y; Jackson, M; Schubert, L

    Purpose: The current standard-of-care imaging used to evaluate lung cancer patients for surgical resection is nuclear-medicine ventilation. Surgeons use nuclear-medicine images along with pulmonary function tests (PFT) to calculate percent predicted postoperative (%PPO) PFT values by estimating the amount of functioning lung that would be lost with surgery. 4DCT-ventilation is an emerging imaging modality developed in radiation oncology that uses 4DCT data to calculate lung ventilation maps. We perform the first retrospective study to assess the use of 4DCT-ventilation for pre-operative surgical evaluation. The purpose of this work was to compare %PPO-PFT values calculated with 4DCT-ventilation and nuclear-medicine imaging. Methods:more » 16 lung cancer patients retrospectively reviewed had undergone 4DCTs, nuclear-medicine imaging, and had Forced Expiratory Volume in 1 second (FEV1) acquired as part of a standard PFT. For each patient, 4DCT data sets, spatial registration, and a density-change based model were used to compute 4DCT-ventilation maps. Both 4DCT and nuclear-medicine images were used to calculate %PPO-FEV1 using %PPO-FEV1=pre-operative FEV1*(1-fraction of total ventilation of resected lung). Fraction of ventilation resected was calculated assuming lobectomy and pneumonectomy. The %PPO-FEV1 values were compared between the 4DCT-ventilation-based calculations and the nuclear-medicine-based calculations using correlation coefficients and average differences. Results: The correlation between %PPO-FEV1 values calculated with 4DCT-ventilation and nuclear-medicine were 0.81 (p<0.01) and 0.99 (p<0.01) for pneumonectomy and lobectomy respectively. The average difference between the 4DCT-ventilation based and the nuclear-medicine-based %PPO-FEV1 values were small, 4.1±8.5% and 2.9±3.0% for pneumonectomy and lobectomy respectively. Conclusion: The high correlation results provide a strong rationale for a clinical trial translating 4DCT-ventilation to the surgical domain. Compared to nuclear-medicine, 4DCT-ventilation is cheaper, does not require a radioactive contrast agent, provides a faster imaging procedure, and has improved spatial resolution. 4DCT-ventilation can reduce the cost and imaging time for patients while providing improved spatial accuracy and quantitative results for surgeons. YV discloses grant from State of Colorado.« less

  8. Applications and interpretation of krypton 81m ventilation/technetium 99m macroaggregate perfusion lung scanning in childhood

    NASA Astrophysics Data System (ADS)

    Davies, Hugh Trevor Frimston

    Radionuclide ventilation perfusion lung scans now play an important part in the investigation of paediatric lung disease, providing a safe, noninvasive assessment of regional lung function in children with suspected pulmonary disease. In paediatric practice the most suitable radionuclides are Krypton 81m (Kr81m) and Technetium 99m (Tc99m), which are jointly used in the Kr81m ventilation/Tc99m macroaggregate perfusion lung scan (V/Q lung scan). The Kr81m ventilation scan involves a low radiation dose, requires little or no subject cooperation and because of the very short half life of Kr81m (13 seconds) the steady state image acquired during continuous inhalation of the radionuclide is considered to reflect regional distribution of ventilation. It is now the most important noninvasive method available for the investigation of the regional abnormalities of ventilation characteristic of many congenital and acquired paediatric respiratory diseases, such as diaphragmatic hernia, pulmonary sequestration, bronchopulmonary dysplasia, foreign body inhalation and bronchiectasis. It improves diagnostic accuracy, aids clinical decision making and is used to monitor the progress of disease and response to therapy. Theoretical analysis of the steady state Kr81m ventilation image suggests that it may only reflect regional ventilation when specific ventilation (ventilation per unit volume of lung) is within or below the normal adult range (1-3 L/L/min). At higher values such as those seen in neonates and infants (8-15 L/L/min) Kr81m activity may reflect regional lung volume rather than ventilation, a conclusion supported by the studies of Ciofetta et al. There is some controversy on this issue as animal studies have demonstrated that the Kr81m image reflects ventilation over a much wider range of specific ventilation (up to 13 L/L/min). A clinical study of sick infants and very young children is in agreement with this animal work and suggests that the steady state Kr81m image still reflects regional ventilation in this age group. The doubt cast on the interpretation of the Kr81m steady state image could limit the value of V/Q lung scans in following regional lung function through childhood, a period when specific ventilation is falling rapidly as the child grows. Therefore the first aim of this study was to examine the application of this theoretical model to children and determine whether the changing specific ventilation seen through childhood significantly alters the interpretation of the steady state Kr81m image. This is a necessary first step before conducting longitudinal studies of regional ventilation and perfusion in children. The effect of posture on regional ventilation and perfusion in the adult human lung has been extensively studied. Radiotracer studies have consistently shown that both ventilation and perfusion are preferentially distributed to dependent lung regions during tidal breathing regardless of posture. There is little published information concerning the pattern in children yet there are many differences in lung and chest wall mechanics of children and adults which, along with clinical observation, have led to the hypothesis that the pattern of regional ventilation observed in adults may not be seen in children. Recent reports of regional ventilation in infants and very young children have provided support for this theory. The paper of Heaf et al demonstrated that these differences may in certain circumstances be clinically important. It is not clear however at what age children adopt the "adult pattern of ventilation". In addition to the problems referred to above, attenuation of Kr81m activity as it passes through the chest wall and the changing geometry of the chest during tidal breathing have made quantitative analysis of the image difficult although fractional ventilation and perfusion to each lung can be calculated from the steady state image. In clinical practise, therefore, ventilation and perfusion are usually assessed by inspection of the steady state image. The aims of the present study were therefore: 1. To critically assess Kr81m ventilation and Tc99m MAA perfusion images in children. 2. To derive fractional ventilation and perfusion to each lung in children with normal chest radiography and homogeneous distribution of the radionuclides. 3. To conduct further studies into the effects of gravity on regional lung function. 4. To apply the technique in clinical practise. 5. To attempt to improve quantitation of the Kr81m ventilation image.

  9. 30 CFR 75.350 - Belt air course ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.350 Belt air course ventilation... manager may approve lower velocities in the ventilation plan based on specific mine conditions. Air... or alarm signal. This training must be conducted prior to working underground in a mine that uses...

  10. 46 CFR 185.352 - Ventilation of gasoline machinery spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Ventilation of gasoline machinery spaces. 185.352... (UNDER 100 GROSS TONS) OPERATIONS Miscellaneous Operating Requirements § 185.352 Ventilation of gasoline machinery spaces. The mechanical exhaust for the ventilation of a gasoline machinery space, required by...

  11. 46 CFR 185.352 - Ventilation of gasoline machinery spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Ventilation of gasoline machinery spaces. 185.352... (UNDER 100 GROSS TONS) OPERATIONS Miscellaneous Operating Requirements § 185.352 Ventilation of gasoline machinery spaces. The mechanical exhaust for the ventilation of a gasoline machinery space, required by...

  12. 46 CFR 185.352 - Ventilation of gasoline machinery spaces.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Ventilation of gasoline machinery spaces. 185.352... (UNDER 100 GROSS TONS) OPERATIONS Miscellaneous Operating Requirements § 185.352 Ventilation of gasoline machinery spaces. The mechanical exhaust for the ventilation of a gasoline machinery space, required by...

  13. 46 CFR 127.260 - Ventilation for accommodations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Ventilation for accommodations. 127.260 Section 127.260... ARRANGEMENTS Particular Construction and Arrangements § 127.260 Ventilation for accommodations. (a) Each... vessel of 100 or more gross tons must be provided with a mechanical ventilation system unless the...

  14. 30 CFR 77.1106 - Battery-charging stations; ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Battery-charging stations; ventilation. 77.1106... COAL MINES Fire Protection § 77.1106 Battery-charging stations; ventilation. Battery-charging stations shall be located in well-ventilated areas. Battery-charging stations shall be equipped with reverse...

  15. 30 CFR 77.1106 - Battery-charging stations; ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Battery-charging stations; ventilation. 77.1106... COAL MINES Fire Protection § 77.1106 Battery-charging stations; ventilation. Battery-charging stations shall be located in well-ventilated areas. Battery-charging stations shall be equipped with reverse...

  16. 30 CFR 77.1106 - Battery-charging stations; ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Battery-charging stations; ventilation. 77.1106... COAL MINES Fire Protection § 77.1106 Battery-charging stations; ventilation. Battery-charging stations shall be located in well-ventilated areas. Battery-charging stations shall be equipped with reverse...

  17. 30 CFR 77.1106 - Battery-charging stations; ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Battery-charging stations; ventilation. 77.1106... COAL MINES Fire Protection § 77.1106 Battery-charging stations; ventilation. Battery-charging stations shall be located in well-ventilated areas. Battery-charging stations shall be equipped with reverse...

  18. 30 CFR 77.1106 - Battery-charging stations; ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Battery-charging stations; ventilation. 77.1106... COAL MINES Fire Protection § 77.1106 Battery-charging stations; ventilation. Battery-charging stations shall be located in well-ventilated areas. Battery-charging stations shall be equipped with reverse...

  19. 21 CFR 868.5935 - External negative pressure ventilator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ventilator. (a) Identification. An external negative pressure ventilator (e.g., iron lung, cuirass) is a device chamber that is intended to support a patient's ventilation by alternately applying and releasing external negative pressure over the diaphragm and upper trunk of the patient. (b) Classification. Class II...

  20. Ventilation practices in subarachnoid hemorrhage: a cohort study exploring the use of lung protective ventilation.

    PubMed

    Marhong, Jonathan D; Ferguson, Niall D; Singh, Jeffrey M

    2014-10-01

    Acute respiratory distress syndrome (ARDS) is common following aneurysmal subarachnoid hemorrhage (SAH), but the influence of mechanical ventilator settings on its development is unclear. We sought to determine adherence to lung protective thresholds in ventilated patients with SAH and describe the association between ventilator settings and subsequent development of ARDS. We conducted a retrospective cohort study of consecutive patients receiving mechanical ventilation within 72 h of SAH at a single academic center. Ventilator settings and blood gas data were collected twice daily for the first 7 days of ventilation along with ICU and hospital outcomes. Lung protective ventilation was defined as follows: tidal volume ≤8 mL/kg of predicted body weight, positive end-expiratory pressure (PEEP) ≥5 cm H(2)O, and peak or plateau pressure ≤30 cm H(2)O. The development of ARDS was ascertained retrospectively by PaO(2)/FiO(2) ≤300 with new bilateral lung opacities on chest X-ray within one day of hypoxemia. We identified 62 patients who underwent early mechanical ventilation following SAH. PS and Continuous Positive Airway Pressure were common ventilator modes with a median tidal volume of 7.8 mL/kg [interquartile range 6.8-8.8], median peak pressure of 14 cm H(2)O [IQR 12-17], and median PEEP of 5 cm H(2)O [IQR 5-6]. Adherence to tidal volumes ≤8 mL/kg was seen in 64 % of all observations and peak pressures <30 cm H(2)O were 94 % of all observations. All three lung protective criteria were seen in 58 % of all observations. Thirty-one patients (50 %) were determined to have ARDS. ARDS patients were more frequently ventilated with a peak pressure >30 cm H(2)O (11.3 % of ARDS ventilation days vs. 0 % of non-ARDS ventilation days; p < 0.01). Initial tidal volume was not associated with subsequent development of ARDS in univariate (p = 0.6) or multivariate analysis (p = 0.49). Only the number of ARDS risk factors was independently associated with the development of ARDS (Adjusted Odds Ratio 2.8 per additional risk factor [95 % CI 1.2-6.5]). Patients with SAH requiring mechanical ventilation frequently breathe spontaneously, generating tidal volumes above usual protective thresholds regardless of meeting ARDS criteria. In patients with SAH, the presence of an additional ARDS risk factor should prompt close screening for the development of ARDS and consideration of adjustment of ventilator settings to meet lung protective thresholds.

  1. Mild hypothermia attenuates changes in respiratory system mechanics and modifies cytokine concentration in bronchoalveolar lavage fluid during low lung volume ventilation.

    PubMed

    Dostál, P; Senkeřík, M; Pařízková, R; Bareš, D; Zivný, P; Zivná, H; Cerný, V

    2010-01-01

    Hypothermia was shown to attenuate ventilator-induced lung injury due to large tidal volumes. It is unclear if the protective effect of hypothermia is maintained under less injurious mechanical ventilation in animals without previous lung injury. Tracheostomized rats were randomly allocated to non-ventilated group (group C) or ventilated groups of normothermia (group N) and mild hypothermia (group H). After two hours of mechanical ventilation with inspiratory fraction of oxygen 1.0, respiratory rate 60 min(-1), tidal volume 10 ml x kg(-1), positive end-expiratory pressure (PEEP) 2 cm H2O or immediately after tracheostomy in non-ventilated animals inspiratory pressures were recorded, rats were sacrificed, pressure-volume (PV) curve of respiratory system constructed, bronchoalveolar lavage (BAL) fluid and aortic blood samples obtained. Group N animals exhibited a higher rise in peak inspiratory pressures in comparison to group H animals. Shift of the PV curve to right, higher total protein and interleukin-6 levels in BAL fluid were observed in normothermia animals in comparison with hypothermia animals and non-ventilated controls. Tumor necrosis factor-alpha was lower in the hypothermia group in comparison with normothermia and non-ventilated groups. Mild hypothermia attenuated changes in respiratory system mechanics and modified cytokine concentration in bronchoalveolar lavage fluid during low lung volume ventilation in animals without previous lung injury.

  2. Identifying Potential Ventilator Auto-Triggering Among Organ Procurement Organization Referrals.

    PubMed

    Henry, Nicholas R; Russian, Christopher J; Nespral, Joseph

    2016-06-01

    Ventilator auto-trigger is the delivery of an assisted mechanical ventilated breath over the set ventilator frequency in the absence of a spontaneous inspiratory effort and can be caused by inappropriate ventilator trigger sensitivity. Ventilator auto-trigger can be misinterpreted as a spontaneous breath and has the potential to delay or prevent brain death testing and confuse health-care professionals and/or patient families. To determine the frequency of organ donor referrals from 1 Organ Procurement Organization (OPO) that could benefit from an algorithm designed to assist organ recovery coordinators to identify and correct ventilator auto-triggering. This retrospective analysis evaluated documentation of organ donor referrals from 1 OPO in central Texas during the 2013 calendar year that resulted in the withdrawal of care by the patient's family and the recovery of organs. The frequency of referrals that presented with absent brain stem reflexes except for additional respirations over the set ventilator rate was determined to assess for the need of the proposed algorithm. Documentation of 672 organ procurement organization referrals was evaluated. Documentation from 42 referrals that resulted in the withdrawal of care and 21 referrals that resulted in the recovery of organs were identified with absent brain stem reflexes except for spontaneous respirations on the mechanical ventilator. As a result, an algorithm designed to identify and correct ventilator auto-trigger could have been used 63 times during the 2013 calendar year. © 2016, NATCO.

  3. Outcome-based ventilation: A framework for assessing performance, health, and energy impacts to inform office building ventilation decisions.

    PubMed

    Rackes, A; Ben-David, T; Waring, M S

    2018-07-01

    This article presents an outcome-based ventilation (OBV) framework, which combines competing ventilation impacts into a monetized loss function ($/occ/h) used to inform ventilation rate decisions. The OBV framework, developed for U.S. offices, considers six outcomes of increasing ventilation: profitable outcomes realized from improvements in occupant work performance and sick leave absenteeism; health outcomes from occupant exposure to outdoor fine particles and ozone; and energy outcomes from electricity and natural gas usage. We used the literature to set low, medium, and high reference values for OBV loss function parameters, and evaluated the framework and outcome-based ventilation rates using a simulated U.S. office stock dataset and a case study in New York City. With parameters for all outcomes set at medium values derived from literature-based central estimates, higher ventilation rates' profitable benefits dominated negative health and energy impacts, and the OBV framework suggested ventilation should be ≥45 L/s/occ, much higher than the baseline ~8.5 L/s/occ rate prescribed by ASHRAE 62.1. Only when combining very low parameter estimates for profitable impacts with very high ones for health and energy impacts were all outcomes on the same order. Even then, however, outcome-based ventilation rates were often twice the baseline rate or more. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. Protective mechanical ventilation does not exacerbate lung function impairment or lung inflammation following influenza A infection.

    PubMed

    Zosky, Graeme R; Cannizzaro, Vincenzo; Hantos, Zoltan; Sly, Peter D

    2009-11-01

    The degree to which mechanical ventilation induces ventilator-associated lung injury is dependent on the initial acute lung injury (ALI). Viral-induced ALI is poorly studied, and this study aimed to determine whether ALI induced by a clinically relevant infection is exacerbated by protective mechanical ventilation. Adult female BALB/c mice were inoculated with 10(4.5) plaque-forming units of influenza A/Mem/1/71 in 50 microl of medium or medium alone. This study used a protective ventilation strategy, whereby mice were anesthetized, tracheostomized, and mechanically ventilated for 2 h. Lung mechanics were measured periodically throughout the ventilation period using a modification of the forced oscillation technique to obtain measures of airway resistance and coefficients of tissue damping and tissue elastance. Thoracic gas volume was measured and used to obtain specific airway resistance, tissue damping, and tissue elastance. At the end of the ventilation period, a bronchoalveolar lavage sample was collected to measure inflammatory cells, macrophage inflammatory protein-2, IL-6, TNF-alpha, and protein leak. Influenza infection caused significant increases in inflammatory cells, protein leak, and deterioration in lung mechanics that were not exacerbated by mechanical ventilation, in contrast to previous studies using bacterial and mouse-specific viral infection. This study highlighted the importance of type and severity of lung injury in determining outcome following mechanical ventilation.

  5. Variable versus conventional lung protective mechanical ventilation during open abdominal surgery: study protocol for a randomized controlled trial.

    PubMed

    Spieth, Peter M; Güldner, Andreas; Uhlig, Christopher; Bluth, Thomas; Kiss, Thomas; Schultz, Marcus J; Pelosi, Paolo; Koch, Thea; Gama de Abreu, Marcelo

    2014-05-02

    General anesthesia usually requires mechanical ventilation, which is traditionally accomplished with constant tidal volumes in volume- or pressure-controlled modes. Experimental studies suggest that the use of variable tidal volumes (variable ventilation) recruits lung tissue, improves pulmonary function and reduces systemic inflammatory response. However, it is currently not known whether patients undergoing open abdominal surgery might benefit from intraoperative variable ventilation. The PROtective VARiable ventilation trial ('PROVAR') is a single center, randomized controlled trial enrolling 50 patients who are planning for open abdominal surgery expected to last longer than 3 hours. PROVAR compares conventional (non-variable) lung protective ventilation (CV) with variable lung protective ventilation (VV) regarding pulmonary function and inflammatory response. The primary endpoint of the study is the forced vital capacity on the first postoperative day. Secondary endpoints include further lung function tests, plasma cytokine levels, spatial distribution of ventilation assessed by means of electrical impedance tomography and postoperative pulmonary complications. We hypothesize that VV improves lung function and reduces systemic inflammatory response compared to CV in patients receiving mechanical ventilation during general anesthesia for open abdominal surgery longer than 3 hours. PROVAR is the first randomized controlled trial aiming at intra- and postoperative effects of VV on lung function. This study may help to define the role of VV during general anesthesia requiring mechanical ventilation. Clinicaltrials.gov NCT01683578 (registered on September 3 3012).

  6. Heliox Improves Carbon Dioxide Removal during Lung Protective Mechanical Ventilation.

    PubMed

    Beurskens, Charlotte J; Brevoord, Daniel; Lagrand, Wim K; van den Bergh, Walter M; Vroom, Margreeth B; Preckel, Benedikt; Horn, Janneke; Juffermans, Nicole P

    2014-01-01

    Introduction. Helium is a noble gas with low density and increased carbon dioxide (CO2) diffusion capacity. This allows lower driving pressures in mechanical ventilation and increased CO2 diffusion. We hypothesized that heliox facilitates ventilation in patients during lung-protective mechanical ventilation using low tidal volumes. Methods. This is an observational cohort substudy of a single arm intervention study. Twenty-four ICU patients were included, who were admitted after a cardiac arrest and mechanically ventilated for 3 hours with heliox (50% helium; 50% oxygen). A fixed protective ventilation protocol (6 mL/kg) was used, with prospective observation for changes in lung mechanics and gas exchange. Statistics was by Bonferroni post-hoc correction with statistical significance set at P < 0.017. Results. During heliox ventilation, respiratory rate decreased (25 ± 4 versus 23 ± 5 breaths min(-1), P = 0.010). Minute volume ventilation showed a trend to decrease compared to baseline (11.1 ± 1.9 versus 9.9 ± 2.1 L min(-1), P = 0.026), while reducing PaCO2 levels (5.0 ± 0.6 versus 4.5 ± 0.6 kPa, P = 0.011) and peak pressures (21.1 ± 3.3 versus 19.8 ± 3.2 cm H2O, P = 0.024). Conclusions. Heliox improved CO2 elimination while allowing reduced minute volume ventilation in adult patients during protective mechanical ventilation.

  7. "Living with dying": the evolution of family members' experience of mechanical ventilation.

    PubMed

    Sinuff, Tasnim; Giacomini, Mita; Shaw, Rhona; Swinton, Marilyn; Cook, Deborah J

    2009-01-01

    Communication with families about mechanical ventilation may be more effective once we gain a better understanding of what families experience and understand about this life support technology when their loved ones are admitted to the intensive care unit (ICU). We conducted in-depth interviews with family members of 27 critically ill patients who required mechanical ventilation for > or = 7 days and had an estimated ICU mortality of > or = 50%. Team members reviewed transcripts independently and used grounded theory analysis. The central theme of family members' experience with mechanical ventilation was "living with dying." Initial reactions to the ventilator were of shock and surprise. Family members perceived no option except mechanical ventilation. Although the ventilator kept the patient alive, it also symbolized proximity to death. In time, families became accustomed to images of the ICU as ventilation became more familiar and routine. Their shock and horror were replaced by hope that the ventilator would allow the body to rest, heal, and recover. However, ongoing exposure to their loved one's critical illness and the new role as family spokesperson were traumatizing. Family members' experiences and their understanding of mechanical ventilation change over time, influenced by their habituation to the ICU environment and its routines. They face uncertainty about death, but maintain hope. Understanding these experiences may engender more respectful, meaningful communication about life support with families.

  8. Household ventilation and tuberculosis transmission in Kampala, Uganda.

    PubMed

    Chamie, G; Wandera, B; Luetkemeyer, A; Bogere, J; Mugerwa, R D; Havlir, D V; Charlebois, E D

    2013-06-01

    To test the feasibility of measuring household ventilation and evaluate whether ventilation is associated with tuberculosis (TB) in household contacts in Kampala, Uganda. Adults with pulmonary TB and their household contacts received home visits to ascertain social and structural household characteristics. Ventilation was measured in air changes per hour (ACH) in each room by raising carbon dioxide (CO₂) levels using dry ice, removing the dry ice, and measuring changes in the natural log of CO₂ (lnCO2) over time. Ventilation was compared in homes with and without co-prevalent TB. Members of 61 of 66 (92%) households approached were enrolled. Households averaged 5.4 residents/home, with a median of one room/home. Twelve homes (20%) reported co-prevalent TB in household contacts. Median ventilation for all rooms was 14 ACH (interquartile range [IQR] 10-18). Median ventilation was 12 vs. 15 ACH in index cases' sleeping rooms in households with vs. those without co-prevalent TB (P = 0.12). Among smear-positive indexes not infected by the human immunodeficiency virus (HIV), median ventilation was 11 vs. 17 ACH in index cases' sleeping rooms in homes with vs. those without co-prevalent TB (P = 0.1). Our findings provide evidence that a simple CO₂ decay method used to measure ventilation in clinical settings can be adapted to homes, adding a novel tool and a neglected variable, ventilation, to the study of household TB transmission.

  9. Building America Case Study: Ventilation System Effectiveness and Tested Indoor Air Quality Impacts, Tyler, Texas

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    ?Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, andmore » filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four System Factor Categories: Balance, Distribution, Outside Air Source, and Recirculation Filtration. Recommended System Factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy.« less

  10. Downregulated Smad4 Affects Extracellular Matrix Remodeling in Ventilator-induced Lung Injury.

    PubMed

    Huang, Xiaofang; Zhou, Wei; Ding, Shifang

    2016-09-01

    To explore the effect of Smad4 on the extracellular matrix remodeling in ventilator-induced lung injury (VILI). We randomized 24 C57BL/6 mice to 4 groups for treatment (n=6/group): control, ventilation, non-targeted (scramble) lentivirus transfection plus ventilation, and Smad4 small interfering RNA (siRNA) lentivirus transfection plus ventilation. Lentivirus was delivered by intranasal instillation. Four weeks later, the 3 ventilated groups underwent high tidal volume (VT 40mL/kg) ventilation to induce lung injury. After 72 hours, lungs were collected from the anesthetized live mice. Histological changes in lungs were evaluated by hematoxylin and eosin and Masson's staining. The expression of α-smooth muscle actin (α-SMA) was determined by immunohistochemistry, and the mRNA and protein levels of Smad4, α-SMA, and collagen I and III were detected by quantitative real-time PCR and western blotting analysis. Smad4 siRNAs significantly knocked down Smad4 expression (P<.05), which was increased with ventilation, thereby alleviating inflammatory cell infiltration. It also inhibited accumulation of α-SMA-positive myofibroblasts and pulmonary fibrosis, as seen by reduced collagen I and III expression (P<.05), induced by ventilation. Scramble siRNA treatment had no effect (P>.05). Smad4 gene silencing may be a therapeutic target for treating ventilator-induced lung injury and pulmonary fibrosis. © 2016 by the Association of Clinical Scientists, Inc.

  11. Immediate ventilatory response to sudden changes in venous return in humans.

    PubMed Central

    Cummin, A R; Iyawe, V I; Jacobi, M S; Mehta, N; Patil, C P; Saunders, K B

    1986-01-01

    We changed venous return transiently by postural manoeuvres, and by lower body positive pressure, to see what happened simultaneously to ventilation. Cardiac output was measured by a Doppler technique. In seven subjects, after inflation of a pressure suit to 80 and 40 mmHg at 30 deg head-up tilt, both cardiac output and ventilation increased. Ventilation increased rapidly to a peak in the first 5 s, cardiac output more slowly to a steady state in about 20 s, at 80 mmHg inflation. After inflation to 80 mmHg in six subjects at 12.5 deg head-up and 30 deg head-down tilt, cardiac output did not change in the first, and fell in the second case. There were no significant changes in ventilation. On release of pressure there were transient increases in both cardiac output and ventilation, with ventilation lagging behind cardiac output, in contrast to (2) above. In five subjects, elevation of the legs at 30 deg head-up tilt caused a rise in both cardiac output and ventilation, but in two subjects neither occurred. In all seven subjects there was a transient increase in cardiac output and ventilation when the legs were lowered. Ventilation and cardiac output changes were approximately in phase. We were therefore unable to dissociate entirely increasing cardiac output from increasing ventilation. The relation between them was certainly not a simple proportional one. PMID:3612571

  12. Clinical characteristics and course of dying in patients with amyotrophic lateral sclerosis withdrawing from long-term ventilation.

    PubMed

    Kettemann, Dagmar; Funke, Andreas; Maier, André; Rosseau, Simone; Meyer, Robert; Spittel, Susanne; Münch, Christoph; Meyer, Thomas

    2017-02-01

    Non-invasive ventilation (NIV) or tracheotomy with invasive ventilation (TIV) are treatment options in ALS. However, a proportion of patients receiving long-term ventilation decide to have it withdrawn. The objective of this study was to analyse the clinical characteristics and palliative approaches in ALS patients withdrawing from long-term ventilation (WLTV). In a cohort study, two different palliative concepts in WLTV were studied: (1) augmented symptom control (ASC; sedation not intended) in patients with ventilator-free tolerance; (2) continuous deep sedation (CDS; sedation intended) in patients without ventilator-free tolerance. Results showed that WLTV was realised in 49 ALS patients (NIV = 13; TIV = 36). Mean daily ventilation was 23.4 h. The ALS Functional Rating Scale (ALSFRS-R) was low (5.6 of 48). Forty-one per cent of patients (n = 20) presented with ophthalmoplegia. ASC was performed in 20 patients, CDS in 29 patients. The mean time to death following disconnection was 32 (0.3-164) h during ASC and 0.3 (0.2-0.6) h in CDS. In conclusion, a low ALSFRS-R, high incidence of ophthalmoplegia and extended ventilator dependency were found before WLTV. The presence or absence of ventilator-free tolerance determined the approach to the management of symptoms, the setting for immediate end-of-life care and the course of dying in WLTV.

  13. Noninvasive ventilation.

    PubMed

    Rabatin, J T; Gay, P C

    1999-08-01

    Noninvasive ventilation refers to the delivery of assisted ventilatory support without the use of an endotracheal tube. Noninvasive positive pressure ventilation (NPPV) can be delivered by using a volume-controlled ventilator, a pressure-controlled ventilator, a bilevel positive airway pressure ventilator, or a continuous positive airway pressure device. During the past decade, there has been a resurgence in the use of noninvasive ventilation, fueled by advances in technology and clinical trials evaluating its use. Several manufacturers produce portable devices that are simple to operate. This review describes the equipment, techniques, and complications associated with NPPV and also the indications for both short-term and long-term applications. NPPV clearly represents an important addition to the techniques available to manage patients with respiratory failure. Future clinical trials evaluating its many clinical applications will help to define populations of patients most apt to benefit from this type of treatment.

  14. Magnetic Resonance Imaging of Ventilation and Perfusion in the Lung

    NASA Technical Reports Server (NTRS)

    Prisk, Gordon Kim (Inventor); Hopkins, Susan Roberta (Inventor); Pereira De Sa, Rui Carlos (Inventor); Theilmann, Rebecca Jean (Inventor); Buxton, Richard Bruce (Inventor); Cronin, Matthew Vincent (Inventor)

    2017-01-01

    Methods, devices, and systems are disclosed for implementing a fully quantitative non-injectable contrast proton MRI technique to measure spatial ventilation-perfusion (VA/Q) matching and spatial distribution of ventilation and perfusion. In one aspect, a method using MRI to characterize ventilation and perfusion in a lung includes acquiring an MR image of the lung having MR data in a voxel and obtaining a breathing frequency parameter, determining a water density value, a specific ventilation value, and a perfusion value in at least one voxel of the MR image based on the MR data and using the water density value to determine an air content value, and determining a ventilation-perfusion ratio value that is the product of the specific ventilation value, the air content value, the inverse of the perfusion value, and the breathing frequency.

  15. A comprehensive evaluation of the toxicology resulting from laser-generated ventilation holes in cigarette filters.

    PubMed

    Coggins, Christopher R E; Merski, Jerome A; Oldham, Michael J

    2013-01-01

    Recent technological advances allow ventilation holes in (or adjacent to) cigarette filters to be produced using lasers instead of using the mechanical procedures of earlier techniques. Analytical chemistry can be used to compare the composition of mainstream smoke from experimental cigarettes having filters with mechanically produced ventilation holes to that of cigarettes with ventilation holes that were produced using laser technology. Established procedures were used to analyze the smoke composition of 38 constituents of mainstream smoke generated using standard conditions. There were no differences between the smoke composition of cigarettes with filter ventilation holes that were produced mechanically or through use of laser technology. The two methods for producing ventilation holes in cigarette filters are equivalent in terms of resulting mainstream smoke chemistry, at two quite different filter ventilation percentages.

  16. Pretest Predictions for Ventilation Tests

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Y. Sun; H. Yang; H.N. Kalia

    The objective of this calculation is to predict the temperatures of the ventilating air, waste package surface, concrete pipe walls, and insulation that will be developed during the ventilation tests involving various test conditions. The results will be used as input to the following three areas: (1) Decisions regarding testing set-up and performance. (2) Assessing how best to scale the test phenomena measured. (3) Validating numerical approach for modeling continuous ventilation. The scope of the calculation is to identify the physical mechanisms and parameters related to thermal response in the ventilation tests, and develop and describe numerical methods that canmore » be used to calculate the effects of continuous ventilation. Sensitivity studies to assess the impact of variation of linear power densities (linear heat loads) and ventilation air flow rates are included. The calculation is limited to thermal effect only.« less

  17. Pressure Dynamic Characteristics of Pressure Controlled Ventilation System of a Lung Simulator

    PubMed Central

    Shi, Yan; Ren, Shuai; Cai, Maolin; Xu, Weiqing; Deng, Qiyou

    2014-01-01

    Mechanical ventilation is an important life support treatment of critically ill patients, and air pressure dynamics of human lung affect ventilation treatment effects. In this paper, in order to obtain the influences of seven key parameters of mechanical ventilation system on the pressure dynamics of human lung, firstly, mechanical ventilation system was considered as a pure pneumatic system, and then its mathematical model was set up. Furthermore, to verify the mathematical model, a prototype mechanical ventilation system of a lung simulator was proposed for experimental study. Last, simulation and experimental studies on the air flow dynamic of the mechanical ventilation system were done, and then the pressure dynamic characteristics of the mechanical system were obtained. The study can be referred to in the pulmonary diagnostics, treatment, and design of various medical devices or diagnostic systems. PMID:25197318

  18. Technology Solutions Case Study: Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    A. Rudd and D. Bergey

    Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, andmore » filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs.« less

  19. 7 CFR 51.1527 - Standard pack.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... peach boxes, lug boxes and small consumer packages. In layer-packed California peach boxes or lug boxes... package. The number of plums or prunes in California peach boxes or lug boxes shall not vary more than 4... container. (ii) Face and fill packs in cartons and lug boxes. In face and fill packs in cartons and lug...

  20. 7 CFR 51.1527 - Standard pack.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... peach boxes, lug boxes and small consumer packages. In layer-packed California peach boxes or lug boxes... package. The number of plums or prunes in California peach boxes or lug boxes shall not vary more than 4... container. (ii) Face and fill packs in cartons and lug boxes. In face and fill packs in cartons and lug...

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