Science.gov

Sample records for comparing displacement ventilation

  1. The role of diffusion in natural displacement ventilation

    NASA Astrophysics Data System (ADS)

    Kaye, Nigel; Flynn, Morris

    2009-11-01

    The classic natural displacement ventilation model of Linden et al. (1990) predicts the formation of a two layer stratification when a single thermal plume is introduced into a room with vents at floor and ceiling level. The model assumes that molecular diffusion plays no role in the development of the rooms ambient stratification as such diffusion is a slow process and the plume entrainment field will act to thin the interface between the warm upper layer and cool lower layer. The prediction of a sharp interface has been confirmed by small scale salt bath experiments. However, full scale measurements and CFD simulations at larger scale indicate that the interface between the two layers is not sharp but smeared out over a finite thickness. We present two simple models for predicting the thickness of the interface as a function of the room height, floor area and vent area as well as the plume buoyancy flux and the thermal diffusivity of the fluid. The interface increases in thickness with increasing room floor area and decreasing plume strength. Our model is compared to interface thickness measurements based on CFD simulations and salt bath models and is shown to agree both phenomenologically and numerically. [4pt] Linden, Lane-Serf, & Smeed, (1990) `Emptying filling boxes, the fluid mechanics of natural ventilation' J. Fluid Mech. 212 pp. 309--335.

  2. Carbon dioxide elimination and gas displacement vary with piston position during high-frequency oscillatory ventilation.

    PubMed

    Hamel, Donna S; Katz, Andrew L; Craig, Damian M; Davies, John D; Cheifetz, Ira M

    2005-03-01

    Alterations in gas displacement in pediatric patients ventilated with the SensorMedics 3100A high-frequency oscillator are most commonly manipulated by adjusting the amplitude, frequency, and percent inspiratory time. The piston-position-and-displacement indicator is commonly centered and subsequently not adjusted. That practice may limit the clinician's ability to optimize carbon dioxide elimination. We hypothesized that varying the piston position would alter gas displacement and carbon dioxide elimination. We conducted an observational study in a tertiary pediatric intensive care unit and a correlated bench study. In the clinical study, 24 patients were ventilated with a SensorMedics 3100A high-frequency oscillator. Transcutaneously measured carbon dioxide ((tCO(2))) values were documented with the piston-position-and-displacement indicator in left, center, and right positions. In the bench study the oscillator was set and maintained at: mean airway pressure 15 cm H(2)O, inspiratory time 33% of respiratory-cycle time, bias flow 20 L/min. A pneumotachometer attached to a respiratory mechanics monitor was placed between the ventilator circuit and a test lung. Data were collected with the piston-position-and-displacement indicator at the left, center, and right positions with frequencies of 4-14 Hz and amplitudes of 25-55 cm H(2)O. Data were collected over a 3-minute time period for each combination of frequency, amplitude, and piston-position-and-displacement-indicator position. We compared the data with repeated-measures analysis of variance. Pairwise comparisons were performed with a 2-tailed Student's test with Bonferroni correction. Among the 24 patients (tCO(2)) was significantly associated with the position of the piston (p < 0.007). In the bench study, gas displacement was higher when the piston-position-and-displacement indicator was positioned to the left (than when at the center position) 91.7% of the time (p < 0.0001). When the piston-position-and-displacement

  3. Liver displacement during ventilation in Thiel embalmed human cadavers - a possible model for research and training in minimally invasive therapies.

    PubMed

    Eisma, Roos; Gueorguieva, Mariana; Immel, Erwin; Toomey, Rachel; McLeod, Graeme; Soames, Roger; Melzer, Andreas

    2013-09-01

    Respiration-related movement of organs is a complication in a range of diagnostic and interventional procedures. The development and validation of techniques to compensate for such movement requires appropriate models. Human cadavers embalmed with the Thiel method remain flexible and could provide a suitable model. In this study liver displacement during ventilation was assessed in eight Thiel embalmed cadavers, all of which showed thoracic and abdominal motion. Four cadavers displayed realistic lung behaviour, one showed some signs of pneumothorax after prolonged ventilation, one had limited filling of the lungs, and two displayed significant leakage of air into the thorax. A coronal slice containing the largest section through the liver was imaged with a real-time Fast Gradient Echo (FGR) MRI sequence: Craniocaudal displacement of the liver was then determined from a time-series of slices. The maximum liver displacement observed in the cadavers ranged from 7 to 35 mm. The ventilation applied was comparable to tidal breathing at rest and the results found for liver displacement are similar to values in the literature for respiratory motion of the liver under similar conditions. This indicates that Thiel embalmed cadavers have potential as a model for research and training in minimally invasive procedures.

  4. Co-occupant's exposure to exhaled pollutants with two types of personalized ventilation strategies under mixing and displacement ventilation systems.

    PubMed

    Li, X; Niu, J; Gao, N

    2013-04-01

    Personalized ventilation (PV) system in conjunction with total ventilation system can provide cleaner inhaled air for the user. Concerns still exist about whether the normally protecting PV device, on the other hand, facilitates the dispersion of infectious agents generated by its user. In this article, two types of PV systems with upward supplied fresh air, namely a chair-based PV and one kind of desk-mounted PV systems, when combined with mixing ventilation (MV) and displacement ventilation (DV) systems, are investigated using simulation method with regard to their impacts on co-occupant's exposure to the exhaled droplet nuclei generated by the infected PV user. Simulation results of tracer gas and particles with aerodynamic diameter of 1, 5, and 10 μm from exhaled air show that, when only the infected person uses a PV, the different PV air supplying directions present very different impacts on the co-occupant's intake under DV, while no apparent differences can be observed under MV. The findings demonstrate that better inhaled air quality can always be achieved under DV when the adopted PV system can deliver conditioned fresh air in the same direction with the mainly upward airflow patterns of DV.

  5. Comparing Teaching Approaches About Maxwell's Displacement Current

    NASA Astrophysics Data System (ADS)

    Karam, Ricardo; Coimbra, Debora; Pietrocola, Maurício

    2014-08-01

    Due to its fundamental role for the consolidation of Maxwell's equations, the displacement current is one of the most important topics of any introductory course on electromagnetism. Moreover, this episode is widely used by historians and philosophers of science as a case study to investigate several issues (e.g. the theory-experiment relationship). Despite the consensus among physics educators concerning the relevance of the topic, there are many possible ways to interpret and justify the need for the displacement current term. With the goal of understanding the didactical transposition of this topic more deeply, we investigate three of its domains: (1) The historical development of Maxwell's reasoning; (2) Different approaches to justify the term insertion in physics textbooks; and (3) Four lectures devoted to introduce the topic in undergraduate level given by four different professors. By reflecting on the differences between these three domains, significant evidence for the knowledge transformation caused by the didactization of this episode is provided. The main purpose of this comparative analysis is to assist physics educators in developing an epistemological surveillance regarding the teaching and learning of the displacement current.

  6. Comparative analysis of selected ventilator types tested within a low velocity wind tunnel

    SciTech Connect

    Schubert, R.P.; Kennedy, B.

    1980-01-01

    Natural ventilation in building design is generally the result of forces arising from buoyancy (stack effect) and wind. An object placed in the path of wind flow causes pressure differentials indicative of the objects shape. These pressure differentials can be used to displace air and hence induce ventilation. This study investigates different ventilator cap types and what effect they have on enhancing air movement. The process and results in which a low velocity wind tunnel was employed to test five basic shapes and their variations are described. Included among these shapes were: exaggerated wing sections, venturi shrouds, delta wings, turbine ventilators and air shields. Each of these geometries were placed on a scaled stack in which the attack and yaw angle were among the variables and were recorded and plotted against induced air movement. The results of these investigations were condensed into a comparative performance index which shows what contribution these cap types can make to natural ventilation and summertime cooling.

  7. Dispersal of exhaled air and personal exposure in displacement ventilated rooms.

    PubMed

    Bjørn, E; Nielsen, P V

    2002-09-01

    The influence of the human exhalation on flow fields, contaminant distributions, and personal exposure in displacement ventilated rooms is studied together with the effects of physical movement. Experiments are conducted in full-scale test rooms with life-sized breathing thermal manikins. Numerical simulations support the experiments. Air exhaled through the mouth can lock in a thermally stratified layer, if the vertical temperature gradient in breathing zone height is sufficiently large. With exhalation through the nose, exhaled air flows to the upper part of the room. The exhalation flow from both nose and mouth is able to penetrate the breathing zone of another person standing nearby. The stratification of exhaled air breaks down if there is physical movement in the room. As movement increases, the concentration distribution in the room will move towards a fully mixed situation. The protective effect of the boundary layer flow around the body of a moving person disappears at low speed, and is reduced for a seated person placed nearby due to horizontal air movements, which can also cause rebreathing of exhaled air for the seated person. The results indicate that the effect of the exhalation flow is no acute problem in most normal ventilation applications. However, exhalation and local effects caused by movement may be worth considering if one wishes to contain contaminants in certain areas, as in the case of tobacco smoking, in hospitals and clinics, or in certain industries.

  8. Negative pressure ventilation and positive pressure ventilation promote comparable levels of ventilator-induced diaphragmatic dysfunction in rats.

    PubMed

    Bruells, Christian S; Smuder, Ashley J; Reiss, Lucy K; Hudson, Matthew B; Nelson, William Bradley; Wiggs, Michael P; Sollanek, Kurt J; Rossaint, Rolf; Uhlig, Stefan; Powers, Scott K

    2013-09-01

    Mechanical ventilation is a life-saving intervention for patients with respiratory failure. Unfortunately, a major complication associated with prolonged mechanical ventilation is ventilator-induced diaphragmatic atrophy and contractile dysfunction, termed ventilator-induced diaphragmatic dysfunction (VIDD). Emerging evidence suggests that positive pressure ventilation (PPV) promotes lung damage (ventilator-induced lung injury [VILI]), resulting in the release of signaling molecules that foster atrophic signaling in the diaphragm and the resultant VIDD. Although a recent report suggests that negative pressure ventilation (NPV) results in less VILI than PPV, it is unknown whether NPV can protect against VIDD. Therefore, the authors tested the hypothesis that compared with PPV, NPV will result in a lower level of VIDD. Adult rats were randomly assigned to one of three experimental groups (n = 8 each): (1) acutely anesthetized control (CON), (2) 12 h of PPV, and (3) 12 h of NPV. Dependent measures included indices of VILI, diaphragmatic muscle fiber cross-sectional area, diaphragm contractile properties, and the activity of key proteases in the diaphragm. Our results reveal that no differences existed in the degree of VILI between PPV and NPV animals as evidenced by VILI histological scores (CON = 0.082 ± 0.001; PPV = 0.22 ± 0.04; NPV = 0.25 ± 0.02; mean ± SEM). Both PPV and NPV resulted in VIDD. Importantly, no differences existed between PPV and NPV animals in diaphragmatic fiber cross-sectional area, contractile properties, and the activation of proteases. These results demonstrate that NPV and PPV result in similar levels of VILI and that NPV and PPV promote comparable levels of VIDD in rats.

  9. Comparative clinical efficacy evaluation of three gingival displacement systems

    PubMed Central

    Shrivastava, Kirti Jajoo; Bhoyar, Anjali; Agarwal, Surendra; Shrivastava, Saurabh; Parlani, Swapnil; Murthy, Varsha

    2015-01-01

    Aim: We compared the clinical efficacy of three gingival displacement systems to accurately record intra-crevicular margins of tooth preparation. Materials and Methods: One mechanical (magic foam cord) and two chemico-mechanical (expasyl paste and retraction cord impregnated with 15% aluminum chloride) gingival displacement systems were used. This study was conducted on the maxillary central incisors of 20 patients (20-60 years old) requiring full coverage restoration. All the three gingival displacement systems were tested in three sessions at an interval of 14 days in same order. The casts were sectioned and viewed under an optical microscope, followed by quantitative measurements of the width of the pre and postretracted sulci. Results: All the three displacement systems produced highly significant horizontal gingival displacement. Retraction cord soaked in 15% aluminum chloride produced maximum displacement (0.74 mm), followed by expasyl paste (0.48 mm) whereas magic foam cord produced the least displacement (0.41 mm). Conclusions: Gingival displacement shown by each displacement system was found to be more than the accepted value necessary for elastomeric impression accuracy (0.2 mm) to record intra-crevicular margins of tooth preparation. PMID:26604620

  10. Comparative study on the ventilation mode of the residential building in Beijing area in winter

    NASA Astrophysics Data System (ADS)

    Wang, G. J.; Li, Q. P.; Guo, Y.; Hu, Y. H.

    2016-08-01

    With the development of residential energy conservation technology, the air tightness requirement of the window is higher and higher. So in winter the cold penetration wind cannot satisfy the requirement of indoor personnel to fresh air. The common ventilation mode includes natural ventilation, natural inlet and mechanical exhaust, wall type ventilator with heat exchange, ventilation unit with heat exchange. Looking for energy saving, comfortable way of ventilation, the application effect of the way of ventilation is evaluated in air distribution and comfort performance and the initial investment by FLUENT software. The conclusion is that the mode of ventilation unit with heat exchange has higher superiority compared with the others.

  11. [Importance of displacement ventilation for operations and small surgical procedures from the infection preventive point of view].

    PubMed

    Kramer, A; Külpmann, R; Wille, F; Christiansen, B; Exner, M; Kohlmann, T; Heidecke, C D; Lippert, H; Oldhafer, K; Schilling, M; Below, H; Harnoss, J C; Assadian, O

    2010-02-01

    Surgical teams need to breathe air that is conducive to their health. An adequate exchange of air ensures oxygen supply, the ventilation of humidity, smells, toxic substances, especially narcotic gases and surgical smoke, pathogens and particles. With regard to the infection risk, DIN 1946 / 4 -differentiates between operation theaters with the highest demand for clean air (operation room class I a), operation theatres with a high demand (operation room class I b) and rooms within the operation theatres without special requirements, meaning that the microbial load in the air is close to or equal to that of normal in-room air quality (room class II). For an operation room class I a, ventilation that displaces the used air is necessary, while a regular ventilation is sufficient for operation room class I b. Because of ambiguous -results in previous studies, the necessity to define a -class I a for operation rooms is being questioned. Therefore, this review focuses on the analysis of the existing publications with respect to this -question. The result of this analysis indicates that so far there is only one surgical procedure, the -implantation of hip endoprosthetics, for which a preventive effect on SSI of a class I a ventilation (displacement of the used air) is documented. One recent study, reviewed critically here, -showed opposite results, but lacks methodological clarity. Thus, it is concluded that evidence for the requirement of operation room classes can only be derived from risk assessment (infection risk by surgical intervention, extent of possible damages), but not from epidemiological studies. Risk assessment must be based on the following criteria: size and depth of the operation field, -duration of the procedure, vascular perfusion of the wound, implantation of alloplastic material and general risk of the patient for an infection. From an infection preventive point of view, no class I a "displacement ventilation" is necessary for small surgical

  12. CT ventilation functional image-based IMRT treatment plans are comparable to SPECT ventilation functional image-based plans.

    PubMed

    Kida, Satoshi; Bal, Matthieu; Kabus, Sven; Negahdar, Mohammadreza; Shan, Xin; Loo, Billy W; Keall, Paul J; Yamamoto, Tokihiro

    2016-03-01

    To investigate the hypothesis that CT ventilation functional image-based IMRT plans designed to avoid irradiating highly-functional lung regions are comparable to single-photon emission CT (SPECT) ventilation functional image-based plans. Three IMRT plans were created for eight thoracic cancer patients using: (1) CT ventilation functional images, (2) SPECT ventilation functional images, and (3) anatomic images (no functional images). CT ventilation images were created by deformable image registration of 4D-CT image data sets and quantitative analysis. The resulting plans were analyzed for the relationship between the deviations of CT-functional plan metrics from anatomic plan metrics (ΔCT-anatomic) and those of SPECT-functional plans (ΔSPECT-anatomic), and moreover for agreements of various metrics between the CT-functional and SPECT-functional plans. The relationship between ΔCT-anatomic and ΔSPECT-anatomic was strong (e.g., R=0.94; linear regression slope 0.71). The average differences and 95% limits of agreement between the CT-functional and SPECT-functional plan metrics (except for monitor units) for various structures were mostly less than 1% and 2%, respectively. This study demonstrated a reasonable agreement between the CT ventilation functional image-based IMRT plans and SPECT-functional plans, suggesting the potential for CT ventilation imaging to serve as a surrogate for SPECT ventilation in functional image-guided radiotherapy. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. Ventilation.

    PubMed

    Turner, W A; Bearg, D W; Brennan, T

    1995-01-01

    This chapter begins with an overview of the history of ventilation guidelines, which has led to the guidelines that are in effect today. Of particular interest is the most recent return in the past 5 years to ventilation rates that more closely reflect a mean or average of the range of guidelines that have existed over the past century. OSHA's and the EPA's recognition of the need to operate ventilation systems in buildings in an accountable manner is also of note. Of even more interest is the resurgence of the concept of minimum mixing and once-through ventilation air that has been pursued in parts of Northern Europe for the past 10 years, and in a school that is being designed with this concept in New Hampshire. In addition, the design concept of equipping office buildings with low pressure drop high efficiency particle filtration to remove fine particles from all of the air that is supplied to the occupants is being used increasingly in the U.S. This chapter also presents an overview of the various types of ventilation systems found in homes and commercial office buildings and the common indoor air quality problems that may be associated with them. It also offers an overview of common HVAC evaluation techniques that can be used to determine if a ventilation system is performing in a manner that makes sense for the use of the space and the needs of the occupants. Are the occupants receiving a reasonable supply of outdoor air? Is the air that they receive of reasonable quality? Are obvious pollutants being exhausted? Ventilation systems have become extremely complex and more difficult to run and maintain over the past 40 years. This trend will continue to drive the need for professionally maintained HVAC equipment that is serviced and run by individuals who are accountable for the quality of the air that the system delivers.

  14. A randomized controlled trial comparing the ventilation duration between adaptive support ventilation and pressure assist/control ventilation in medical patients in the ICU.

    PubMed

    Kirakli, Cenk; Naz, Ilknur; Ediboglu, Ozlem; Tatar, Dursun; Budak, Ahmet; Tellioglu, Emel

    2015-06-01

    Adaptive support ventilation (ASV) is a closed loop mode of mechanical ventilation (MV) that provides a target minute ventilation by automatically adapting inspiratory pressure and respiratory rate with the minimum work of breathing on the part of the patient. The aim of this study was to determine the effect of ASV on total MV duration when compared with pressure assist/control ventilation. Adult medical patients intubated and mechanically ventilated for > 24 h in a medical ICU were randomized to either ASV or pressure assist/control ventilation. Sedation and medical treatment were standardized for each group. Primary outcome was the total MV duration. Secondary outcomes were the weaning duration, number of manual settings of the ventilator, and weaning success rates. Two hundred twenty-nine patients were included. Median MV duration until weaning, weaning duration, and total MV duration were significantly shorter in the ASV group (67 [43-94] h vs 92 [61-165] h, P = .003; 2 [2-2] h vs 2 [2-80] h, P = .001; and 4 [2-6] days vs 4 [3-9] days, P = .016, respectively). Patients in the ASV group required fewer total number of manual settings on the ventilator to reach the desired pH and Paco2 levels (2 [1-2] vs 3 [2-5], P < .001). The number of patients extubated successfully on the first attempt was significantly higher in the ASV group (P = .001). Weaning success and mortality at day 28 were comparable between the two groups. In medical patients in the ICU, ASV may shorten the duration of weaning and total MV duration with a fewer number of manual ventilator settings. ClinicalTrials.gov; No.: NCT01472302; URL: www.clinicaltrials.gov.

  15. 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

  16. Comparing the effectiveness of interventions to improve ventilation behavior in primary schools.

    PubMed

    Geelen, L M J; Huijbregts, M A J; Ragas, A M J; Bretveld, R W; Jans, H W A; van Doorn, W J; Evertz, S J C J; van der Zijden, A

    2008-10-01

    Poor air quality in schools has been associated with adverse health effects. Indoor air quality can be improved by increasing ventilation. The objective of this study was to compare the effectiveness of different interventions to improve ventilation behavior in primary schools. We used indoor CO(2) concentrations as an indicator. In 81 classes of 20 Dutch primary schools, we applied three different interventions: (i) a class-specific ventilation advice; (ii) the advice combined with a CO(2) warning device and (iii) the advice combined with a teaching package. The effectiveness of the interventions was tested directly after intervention and 6 weeks after intervention by measuring the CO(2) concentrations and comparison with a control group (iv). Before intervention, the CO(2) concentration exceeded 1000 ppm for 64% of the school day. The class-specific ventilation advice without further support appeared an ineffective tool to improve ventilation behavior. The advice in combination with a CO(2) warning device or the teaching package proved effective tools and resulted in lower indoor CO(2) concentrations when compared with the control group. Ventilation was significantly improved, but CO(2) concentrations still exceeded 1000 ppm for more than 40% of the school day. Hence, until ventilation facilities are upgraded, the CO(2) warning device and the teaching package are useful low-cost tools. To improve ventilation behavior and indoor air quality in schools, CO(2) warning device and teaching package combined with a class-specific ventilation advice, are effective tools, while giving the ventilation advice solely, is not effective. Although ventilation is significantly improved through behavioral change, the ventilation rate is still insufficient to maintain good air quality during the full school day. Therefore, the improvement of the ventilation facilities is recommended. Hence, until ventilation facilities in schools are upgraded, the CO(2) warning device and the

  17. Comparing Teaching Approaches about Maxwell's Displacement Current

    ERIC Educational Resources Information Center

    Karam, Ricardo; Coimbra, Debora; Pietrocola, Maurício

    2014-01-01

    Due to its fundamental role for the consolidation of Maxwell's equations, the displacement current is one of the most important topics of any introductory course on electromagnetism. Moreover, this episode is widely used by historians and philosophers of science as a case study to investigate several issues (e.g. the theory-experiment…

  18. Comparing Teaching Approaches about Maxwell's Displacement Current

    ERIC Educational Resources Information Center

    Karam, Ricardo; Coimbra, Debora; Pietrocola, Maurício

    2014-01-01

    Due to its fundamental role for the consolidation of Maxwell's equations, the displacement current is one of the most important topics of any introductory course on electromagnetism. Moreover, this episode is widely used by historians and philosophers of science as a case study to investigate several issues (e.g. the theory-experiment…

  19. Performance characteristics of five new anesthesia ventilators and four intensive care ventilators in pressure-support mode: a comparative bench study.

    PubMed

    Jaber, Samir; Tassaux, Didier; Sebbane, Mustapha; Pouzeratte, Yvan; Battisti, Anne; Capdevila, Xavier; Eledjam, Jean-Jacques; Jolliet, Philippe

    2006-11-01

    During the past few years, many manufacturers have introduced new modes of ventilation in anesthesia ventilators, especially partial-pressure modalities. The current bench test study was designed to compare triggering and pressurization of five new anesthesia ventilators with four intensive care unit ventilators. Ventilators were connected to a two-compartment lung model. One compartment was driven by an intensive care unit ventilator to mimic "patient" inspiratory effort, whereas the other was connected to the tested ventilator. The settings of ventilators were positive end-expiratory pressures of 0 and 5 cm H2O, and pressure-support ventilation levels of 10, 15, and 20 cm H2O with normal and high "patient" inspiratory effort. For the anesthesia ventilators, all the measurements were obtained for a low (1 l/min) and a high (10 l/min) fresh gas flow. Triggering delay, triggering workload, and pressurization at 300 and 500 ms were analyzed. For the five tested anesthesia ventilators, the pressure-support ventilation modality functioned correctly. For inspiratory triggering, the three most recent anesthesia machines (Fabius, Drägerwerk AG, Lübeck, Germany; Primus, Drägerwerk AG; and Avance, GE-Datex-Ohemda, Munchen, Germany) had a triggering delay of less than 100 ms, which is considered clinically satisfactory and is comparable to intensive care unit machines. The use of positive end-expiratory pressure modified the quality of delivered pressure support for two anesthesia ventilators (Kion, Siemens AG, Munich, Germany; and Felix, Taema, Antony, France). Three of the five anesthesia ventilators exhibited pressure-support ventilation performance characteristics comparable to those of the intensive care unit machines. Increasing fresh gas flow (1 to 10 l/min) in the internal circuit did not influence the pressure-support ventilation performance of the anesthesia ventilators. Regarding trigger sensitivity and the system's ability to meet inspiratory flow during

  20. Assisted Ventilation.

    PubMed

    Dries, David J

    2016-01-01

    Controlled Mechanical Ventilation may be essential in the setting of severe respiratory failure but consequences to the patient including increased use of sedation and neuromuscular blockade may contribute to delirium, atelectasis, and diaphragm dysfunction. Assisted ventilation allows spontaneous breathing activity to restore physiological displacement of the diaphragm and recruit better perfused lung regions. Pressure Support Ventilation is the most frequently used mode of assisted mechanical ventilation. However, this mode continues to provide a monotonous pattern of support for respiration which is normally a dynamic process. Noisy Pressure Support Ventilation where tidal volume is varied randomly by the ventilator may improve ventilation and perfusion matching but the degree of support is still determined by the ventilator. Two more recent modes of ventilation, Proportional Assist Ventilation and Neurally Adjusted Ventilatory Assist (NAVA), allow patient determination of the pattern and depth of ventilation. Proposed advantages of Proportional Assist Ventilation and NAVA include decrease in patient ventilator asynchrony and improved adaptation of ventilator support to changing patient demand. Work of breathing can be normalized with these modes as well. To date, however, a clear pattern of clinical benefit has not been demonstrated. Existing challenges for both of the newer assist modes include monitoring patients with dynamic hyperinflation (auto-positive end expiratory pressure), obstructive lung disease, and air leaks in the ventilator system. NAVA is dependent on consistent transduction of diaphragm activity by an electrode system placed in the esophagus. Longevity of effective support with this technique is unclear.

  1. Registration-based estimates of local lung tissue expansion compared to xenon-CT measures of specific ventilation

    PubMed Central

    Reinhardt, Joseph M.; Ding, Kai; Cao, Kunlin; Christensen, Gary E.; Hoffman, Eric A.; Bodas, Shalmali V.

    2008-01-01

    The main function of the respiratory system is gas exchange. Since many disease or injury conditions can cause biomechanical or material property changes that can alter lung function, there is a great interest in measuring regional lung ventilation and regional specific volume change. We describe a registration-based technique for estimating local lung expansion from multiple respiratory-gated CT images of the thorax. The degree of regional lung expansion is measured using the Jacobian (a function of local partial derivatives) of the registration displacement field, which we show is directly related to specific volume change. We compare the ventral-dorsal patterns of lung expansion estimated across five pressure changes to a xenon CT based measure of specific ventilation in five anesthetized sheep studied in the supine orientation. Using 3D image registration to match images acquired at 10 cm H2O and 15 H2O airway pressures gave the best match between the average Jacobian and the xenon CT specific ventilation (linear regression, average r2 = 0.73). PMID:18501665

  2. Registration-based estimates of local lung tissue expansion compared to xenon CT measures of specific ventilation.

    PubMed

    Reinhardt, Joseph M; Ding, Kai; Cao, Kunlin; Christensen, Gary E; Hoffman, Eric A; Bodas, Shalmali V

    2008-12-01

    The main function of the respiratory system is gas exchange. Since many disease or injury conditions can cause biomechanical or material property changes that can alter lung function, there is a great interest in measuring regional lung ventilation and regional specific volume change. We describe a registration-based technique for estimating local lung expansion from multiple respiratory-gated CT images of the thorax. The degree of regional lung expansion is measured using the Jacobian (a function of local partial derivatives) of the registration displacement field, which we show is directly related to specific volume change. We compare the ventral-dorsal patterns of lung expansion estimated across five pressure changes to a xenon CT based measure of specific ventilation in five anesthetized sheep studied in the supine orientation. Using 3D image registration to match images acquired at 10 cm H(2)O and 15 cm H(2)O airway pressures gave the best match between the average Jacobian and the xenon CT specific ventilation (linear regression, average r(2)=0.73).

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

    SciTech Connect

    Kida, S; Bal, M; Kabus, S; Loo, B; Keall, P; Yamamoto, T

    2014-06-15

    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 (a 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

  4. Compared with specialist registrars, experienced staff nurses shorten the duration of weaning neonates from mechanical ventilation.

    PubMed

    Luyt, Karen; Boyle, Breidge; Wright, Dave E; Petros, Andy J

    2002-10-01

    To compare the overall performance of specially trained neonatal nurses acting autonomously, unsupervised, and without a protocol with specialist registrars when weaning neonates from mechanical ventilation. Prospective, randomized, controlled trial. A single neonatal intensive care unit. Neonates requiring conventional mechanical ventilation (n = 50). Infants on conventional ventilation were randomly assigned to receive either nurse-led (n = 25) or registrar-led (n = 23) weaning. A total of 48 infants completed the study (two infants in the registrar group were excluded when their parents withdrew consent). The main outcome measure, median weaning time, was 1200 mins (95% confidence interval [CI], 621-1779 mins) in the nurse group and 3015 mins (95% CI, 2650-3380 mins) in the registrar group (p = .0458). The median time from treatment assignment to the first ventilator change was 60 mins (95% CI, 52-68 mins) in the nurse group and 120 mins (95% CI, 103-137 mins) in the registrar group (p = .35). On average, the nurses made ventilator changes every 4.5 hrs (95% CI, 2.9-6 hrs) and the registrars every 7.2 hrs (95% CI, 5.4-9 hrs; p = .003). The median number (range) of backward steps taken per infant was 0 (0-5 steps) in the nurse group and 1 (0-5 steps) in the registrar group (p = .019). The findings of this study suggest that additional domains of neonatal critical care could be reviewed for their potential transfer to appropriately prepared nurses.

  5. Ventilator setting in ICUs: comparing a Dutch with a European cohort.

    PubMed

    van IJzendoorn, M C O; Koopmans, M; Strauch, U; Heines, S; den Boer, S; Kors, B M; van der Voort, P H J; Dennesen, P J W; van den Hul, I; Alberts, E; Egbers, P; Esteban, A; Frutos-Vivar, F; Kuiper, M A

    2014-11-01

    From data collected during the third International Study on Mechanical Ventilation (ISMV), we compared data from a Dutch cohort with a European cohort. We hypothesised that tidal volumes were smaller and applied positive end-expiratory pressure (PEEP) was higher in the Netherlands, compared with the European cohort. We also compared use of non-invasive ventilation (NIV) and outcomes in both cohorts. A post-hoc analysis of a prospective observational study of patients receiving mechanical ventilation. Tidal volumes were smaller (7.6 vs. 8.1 ml÷kg predicted bodyweight) in the Dutch cohort and applied PEEP was higher (8 vs. 6 cm H2O). Fewer patients admitted in the Netherlands received NIV as first mode of mechanical ventilation (7.1 vs. 16.7%). Fewer patients in the Dutch cohort developed an ICU-acquired pneumonia (4.5 vs. 12.3%, p < 0.01) and sepsis (5.7 vs. 10.9%, p = 0.03), but more patients were diagnosed as having delirium (15.8 vs. 4.6%, p < 0.01). ICU and in-hospital mortality rates were 19% and 25%, respectively, in Dutch ICUs vs. 26% and 33% in Europe (p = 0.06 and 0.03). Tidal volumes were smaller and applied PEEP was higher in the Dutch cohort compared with international data, but both Dutch and international patients received larger tidal volumes than recommended for prevention or treatment of acute respiratory distress syndrome. NIV as first mode of mechanical ventilation is less commonly used in the Netherlands. The incidence of ICU-acquired pneumonia is lower and of delirium higher in the Netherlands compared with international data.

  6. 4D-Imaging of the Lung: Reproducibility of Lesion Size and Displacement on Helical CT, MRI, and Cone Beam CT in a Ventilated Ex Vivo System

    SciTech Connect

    Biederer, Juergen Dinkel, Julien; Remmert, Gregor; Jetter, Siri; Nill, Simeon; Moser, Torsten; Bendl, Rolf; Thierfelder, Carsten; Fabel, Michael; Oelfke, Uwe; Bock, Michael; Plathow, Christian; Bolte, Hendrik; Welzel, Thomas; Hoffmann, Beata; Hartmann, Guenter; Schlegel, Wolfgang; Debus, Juergen; Heller, Martin

    2009-03-01

    Purpose: Four-dimensional (4D) imaging is a key to motion-adapted radiotherapy of lung tumors. We evaluated in a ventilated ex vivo system how size and displacement of artificial pulmonary nodules are reproduced with helical 4D-CT, 4D-MRI, and linac-integrated cone beam CT (CBCT). Methods and Materials: Four porcine lungs with 18 agarose nodules (mean diameters 1.3-1.9 cm), were ventilated inside a chest phantom at 8/min and subject to 4D-CT (collimation 24 x 1.2 mm, pitch 0.1, slice/increment 24x10{sup 2}/1.5/0.8 mm, pitch 0.1, temporal resolution 0.5 s), 4D-MRI (echo-shared dynamic three-dimensional-flash; repetition/echo time 2.13/0.72 ms, voxel size 2.7 x 2.7 x 4.0 mm, temporal resolution 1.4 s) and linac-integrated 4D-CBCT (720 projections, 3-min rotation, temporal resolution {approx}1 s). Static CT without respiration served as control. Three observers recorded lesion size (RECIST-diameters x/y/z) and axial displacement. Interobserver- and interphase-variation coefficients (IO/IP VC) of measurements indicated reproducibility. Results: Mean x/y/z lesion diameters in cm were equal on static and dynamic CT (1.88/1.87; 1.30/1.39; 1.71/1.73; p > 0.05), but appeared larger on MRI and CBCT (2.06/1.95 [p < 0.05 vs. CT]; 1.47/1.28 [MRI vs. CT/CBCT p < 0.05]; 1.86/1.83 [CT vs. CBCT p < 0.05]). Interobserver-VC for lesion sizes were 2.54-4.47% (CT), 2.29-4.48% (4D-CT); 5.44-6.22% (MRI) and 4.86-6.97% (CBCT). Interphase-VC for lesion sizes ranged from 2.28% (4D-CT) to 10.0% (CBCT). Mean displacement in cm decreased from static CT (1.65) to 4D-CT (1.40), CBCT (1.23) and MRI (1.16). Conclusions: Lesion sizes are exactly reproduced with 4D-CT but overestimated on 4D-MRI and CBCT with a larger variability due to limited temporal and spatial resolution. All 4D-modalities underestimate lesion displacement.

  7. 4D-Imaging of the lung: reproducibility of lesion size and displacement on helical CT, MRI, and cone beam CT in a ventilated ex vivo system.

    PubMed

    Biederer, Juergen; Dinkel, Julien; Remmert, Gregor; Jetter, Siri; Nill, Simeon; Moser, Torsten; Bendl, Rolf; Thierfelder, Carsten; Fabel, Michael; Oelfke, Uwe; Bock, Michael; Plathow, Christian; Bolte, Hendrik; Welzel, Thomas; Hoffmann, Beata; Hartmann, Günter; Schlegel, Wolfgang; Debus, Jürgen; Heller, Martin; Kauczor, Hans-Ulrich

    2009-03-01

    Four-dimensional (4D) imaging is a key to motion-adapted radiotherapy of lung tumors. We evaluated in a ventilated ex vivo system how size and displacement of artificial pulmonary nodules are reproduced with helical 4D-CT, 4D-MRI, and linac-integrated cone beam CT (CBCT). Four porcine lungs with 18 agarose nodules (mean diameters 1.3-1.9 cm), were ventilated inside a chest phantom at 8/min and subject to 4D-CT (collimation 24 x 1.2 mm, pitch 0.1, slice/increment 24 x 10(2)/1.5/0.8 mm, pitch 0.1, temporal resolution 0.5 s), 4D-MRI (echo-shared dynamic three-dimensional-flash; repetition/echo time 2.13/0.72 ms, voxel size 2.7 x 2.7 x 4.0 mm, temporal resolution 1.4 s) and linac-integrated 4D-CBCT (720 projections, 3-min rotation, temporal resolution approximately 1 s). Static CT without respiration served as control. Three observers recorded lesion size (RECIST-diameters x/y/z) and axial displacement. Interobserver- and interphase-variation coefficients (IO/IP VC) of measurements indicated reproducibility. Mean x/y/z lesion diameters in cm were equal on static and dynamic CT (1.88/1.87; 1.30/1.39; 1.71/1.73; p > 0.05), but appeared larger on MRI and CBCT (2.06/1.95 [p < 0.05 vs. CT]; 1.47/1.28 [MRI vs. CT/CBCT p < 0.05]; 1.86/1.83 [CT vs. CBCT p < 0.05]). Interobserver-VC for lesion sizes were 2.54-4.47% (CT), 2.29-4.48% (4D-CT); 5.44-6.22% (MRI) and 4.86-6.97% (CBCT). Interphase-VC for lesion sizes ranged from 2.28% (4D-CT) to 10.0% (CBCT). Mean displacement in cm decreased from static CT (1.65) to 4D-CT (1.40), CBCT (1.23) and MRI (1.16). Lesion sizes are exactly reproduced with 4D-CT but overestimated on 4D-MRI and CBCT with a larger variability due to limited temporal and spatial resolution. All 4D-modalities underestimate lesion displacement.

  8. Comparing the impact of time displaced and biased precipitation estimates for online updated urban runoff models.

    PubMed

    Borup, Morten; Grum, Morten; Mikkelsen, Peter Steen

    2013-01-01

    When an online runoff model is updated from system measurements, the requirements of the precipitation input change. Using rain gauge data as precipitation input there will be a displacement between the time when the rain hits the gauge and the time where the rain hits the actual catchment, due to the time it takes for the rain cell to travel from the rain gauge to the catchment. Since this time displacement is not present for system measurements the data assimilation scheme might already have updated the model to include the impact from the particular rain cell when the rain data is forced upon the model, which therefore will end up including the same rain twice in the model run. This paper compares forecast accuracy of updated models when using time displaced rain input to that of rain input with constant biases. This is done using a simple time-area model and historic rain series that are either displaced in time or affected with a bias. The results show that for a 10 minute forecast, time displacements of 5 and 10 minutes compare to biases of 60 and 100%, respectively, independent of the catchments time of concentration.

  9. Body Density Estimates from Upper-Body Skinfold Thicknesses Compared to Air-Displacement Plethysmography

    USDA-ARS?s Scientific Manuscript database

    Technical Summary Objectives: Determine the effect of body mass index (BMI) on the accuracy of body density (Db) estimated with skinfold thickness (SFT) measurements compared to air displacement plethysmography (ADP) in adults. Subjects/Methods: We estimated Db with SFT and ADP in 131 healthy men an...

  10. Percutaneous transtracheal ventilation: effects of a new oxygen flow modulator on oxygenation and ventilation in pigs compared with a hand triggered emergency jet injector.

    PubMed

    Preussler, Niels-Peter; Schreiber, Torsten; Hüter, Lars; Gottschall, Reiner; Schubert, Harald; Rek, Helga; Karzai, Waheedullah; Schwarzkopf, Konrad

    2003-03-01

    The application of percutaneous transtracheal jet ventilation for emergency ventilation depends on special equipment which is often not available outside the operating room. The oxygen flow modulator is a new specially designed device for emergency ventilation using a low pressure oxygen supply. We studied the effects of the new device in comparison with a hand triggered emergency jet injector on oxygenation and ventilation in six pigs (21+/-1 kg). The animals were anaesthetized, tracheally intubated, and mechanically ventilated. Following central venous and pulmonary artery catheterization, a Paratrend 7 sensor was placed in the left femoral artery for continuous measurements of PaO(2) and PaCO(2). Then an emergency transtracheal airway catheter was inserted into the trachea after surgical exposure. In randomized order each animal was ventilated via the transtracheal airway catheter with the hand triggered emergency jet injector (inspiratory/expiratory (I/E) ratio of 1:1; respiratory rate of 60 min(-1); driving pressure 1.5 bar; FjetO(2) 1.0) and the oxygen flow modulator (FiO(2) 1.0 at an oxygen flow of 15 l min(-1); respiratory rate of 60 min(-1); I/E ratio of approximately 1:1) for 15 min each. After each phase of the experiment respiratory and hemodynamic variables were measured. Whereas PaO(2) was not significantly different between the two devices, PaCO(2) was higher during the hand-triggered jet ventilation. Thus, the efficacy of the oxygen flow modulator during the experiment was comparable with the efficacy of the hand triggered emergency jet injector.

  11. A comparative study of two- versus one-lung ventilation for needlescopic bleb resection.

    PubMed

    Kim, H; Kim, H K; Kang, D-Y; Lee, D-K; Choi, Y H; Lim, S H

    2011-05-01

    This prospective study was conducted to evaluate the feasibility of two-lung (TL) ventilation with low tidal volume anaesthesia compared with one-lung (OL) ventilation for needlescopic bleb resection. Patients with spontaneous pneumothorax that underwent bleb resection with a 2-mm thoracoscope were enrolled. During the operation, the tidal volume was set at 4.0 mL·kg⁻¹ in the TL group and 8.0 mL·kg⁻¹ in the OL group; the respiration rate was set at 23 and 12 breaths·min⁻¹, respectively, at the same inspiratory oxygen fraction (50%). A total of 108 patients (55 patients in the TL group and 53 in the OL group) were included in this study. Airway pressure was significantly lower in the TL group (mean ± sd 8.0 ± 3.3 versus 24.0 ± 3.9 mmHg in the OL group; p<0.001). The time from endotracheal intubation to the incision was 17.1 ± 4.0 min in the TL group and 35.3 ± 7.6 min in the OL group, which was significantly different (p<0.001). However, the operation time was not different in comparisons between the two groups. Therefore, the total anaesthesia time was significantly longer in the OL group (77.9 ± 21.6 versus 64.9 ± 14.7 min in the TL group; p = 0.002). Needlescopic bleb resection using TL ventilation anaesthesia with low tidal volume was technically feasible, cost-effective and time-saving compared with OL ventilation anaesthesia.

  12. Clinical exam and electrovibratography detecting articular disk displacement: a comparative study.

    PubMed

    Abrão, André Felipe; Paiva, Guiovaldo; Weffort, Soo Young Kim; de Fantini, Solange Mongelli

    2011-10-01

    The complete evaluation of the stomatognathic system is essential for orthodontic diagnosis and treatment planning. The evaluation should not only include the occlusal static aspects, but also the functional aspects. This is because the latter could be altered and one or more components of the stomatognathic system could be involved, including the temporomandibular joint (TMJ). The most usual alteration found is articular disk displacement, which can affect the prognosis, and eventually the result in the need for orthodontic treatment. In order to add to the literature on recognition of these alterations, the purpose of this study was to compare the findings of two calibrated examiners on disk displacement clinical diagnosis, and the possible matching between the clinical examination and the electrovibratography (EVG) as methods of disk displacement detection. The sample was composed of 60 patients, divided equally into four groups of 15 participants each, depending on the presence or absence of disk displacement determined by a clinical examination performed by two trained examiners and according to gender. One of the trained operators used EVG and SonoPAK (BioResearch, Inc., Brown Deer, WI) software. The results of the two examiners' findings, one using clinical examination and the other using EVG and SonoPak software. The results were analyzed by applying the kappa coefficient. The findings of the two examiners were very close, resulting in an excellent agreement, and the comparison between the clinical examination and EVG findings resulted in satisfactory agreement between the methods.

  13. The usability of ventilators: a comparative evaluation of use safety and user experience.

    PubMed

    Morita, Plinio P; Weinstein, Peter B; Flewwelling, Christopher J; Bañez, Carleene A; Chiu, Tabitha A; Iannuzzi, Mario; Patel, Aastha H; Shier, Ashleigh P; Cafazzo, Joseph A

    2016-08-20

    The design complexity of critical care ventilators (CCVs) can lead to use errors and patient harm. In this study, we present the results of a comparison of four CCVs from market leaders, using a rigorous methodology for the evaluation of use safety and user experience of medical devices. We carried out a comparative usability study of four CCVs: Hamilton G5, Puritan Bennett 980, Maquet SERVO-U, and Dräger Evita V500. Forty-eight critical care respiratory therapists participated in this fully counterbalanced, repeated measures study. Participants completed seven clinical scenarios composed of 16 tasks on each ventilator. Use safety was measured by percentage of tasks with use errors or close calls (UE/CCs). User experience was measured by system usability and workload metrics, using the Post-Study System Usability Questionnaire (PSSUQ) and the National Aeronautics and Space Administration Task Load Index (NASA-TLX). Nine of 18 post hoc contrasts between pairs of ventilators were significant after Bonferroni correction, with effect sizes between 0.4 and 1.09 (Cohen's d). There were significantly fewer UE/CCs with SERVO-U when compared to G5 (p = 0.044) and V500 (p = 0.020). Participants reported higher system usability for G5 when compared to PB980 (p = 0.035) and higher system usability for SERVO-U when compared to G5 (p < 0.001), PB980 (p < 0.001), and V500 (p < 0.001). Participants reported lower workload for G5 when compared to PB980 (p < 0.001) and lower workload for SERVO-U when compared to PB980 (p < 0.001) and V500 (p < 0.001). G5 scored better on two of nine possible comparisons; SERVO-U scored better on seven of nine possible comparisons. Aspects influencing participants' performance and perception include the low sensitivity of G5's touchscreen and the positive effect from the quality of SERVO-U's user interface design. This study provides empirical evidence of how four ventilators from market leaders compare and

  14. Acute effects of external negative pressure ventilation in chronic obstructive pulmonary disease compared with normal subjects.

    PubMed

    Cooper, C B; Harris, N D; Howard, P

    1991-01-01

    This study compares the acute physiological effects of external negative pressure ventilation (ENPV) in normal subjects and patients with chronic obstructive pulmonary disease (COPD). The equipment consisted of an airtight jacket (Pneumosuit) and vacuum pump. Minute ventilation (Ve) was recorded using a light-emitting turbine transducer. Oxygen uptake (VO2) and carbon dioxide output (VCO2) were calculated every 30 s. Measurements were made at rest and during ENPV with pressures of -20 cmH2O and -40 cmH2O. The ventilator rate was fixed at 16.min-1. In 10 normal subjects, Ve increased from 8.6 to 22.9 l.min-1 (p less than 0.01) accompanied by an increase in VCO2 from 0.25 to 0.39 l.min-1 (p less than 0.01). In 10 normocapnic COPD patients (arterial carbon dioxide tension (PaCO2) less than 6.0 kPa) Ve increased from 11.5 to 17.1 l.min-1 (p less than 0.01) whilst in 10 hypercapnic patients (PaCO2 greater than 6.0 kPa) Ve increased from 9.7 to 12.4 l.min-1 (p less than 0.01). A change in VCO2 was not detected in the COPD patients, and VO2 did not change in any group. Arterial blood samples were obtained in eight hypercapnic patients. Baseline mean physiological deadspace ventilation (VD) was calculated to be 4.9 l.min-1 (56% of Ve) whilst Ve was 8.8 l.min-1 in this subgroup. During ENPV, arterial oxygen tension (PaO2) increased from 6.8 to 8.2 kPa (p less than 0.01) whilst PaCO2 decreased from 6.8 to 5.8 kPa (p less than 0.01) suggesting that despite the large physiological deadspace, a significant increase in alveolar ventilation had occurred. In advanced COPD, thoracic compliance falls and limits the ventilatory response to ENPV.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. [Intensive care unit profesionals's knowledge about non invasive ventilation comparative analysis].

    PubMed

    Raurell-Torredà, M; Argilaga-Molero, E; Colomer-Plana, M; Ruiz-García, T; Galvany-Ferrer, A; González-Pujol, A

    2015-01-01

    The literature highlights the lack of noninvasive ventilation (NIV) protocols and the variability of the knowledge of NIV between intensive care units (ICU) and hospitals, so we want to compare NIV nurses's Knowledge from 4 multipurpose ICU and one surgical ICU. Multicenter, crosscutting, descriptive study in three university hospitals. The survey instrument was validated in a pilot test, and the calculated Kappa index was 0.9. Returning a completed survey is an indication of informed consent. Analysis by Chi square test. 117 responded (65%) nurses, 11±9.7 years of experience in ICU and 9.2±7.2 in use of NIV. One of the multipurpose ICU, was initiated NIV an average of 6 years later than the others (95% CI [3.3 to 8.6], P<.001). Only 23.1% of nurses would place a non-vented mask (with no exhalation port) by conventional ventilator, the rest any kind of face mask. 12.7% believed that the mask must be adjusted to the "2-finger" fit while 29% would seal the mask to the patient's face and cover the mask opening where air escapes to facilitate patient/ventilator synchronization. In the surgical ICU agitation identifies mostly as a complication of NIV compared with multipurpose UCIs (31.6% vs 1.8%, P<.001). 56.4% of nurses do not consider respiratory physiotherapy as nursing care, with no difference between units. Knowledge about types of interface is very dependent on the material of the unit. More training for complications of NIV as agitation and handling secretions it is necessary. Copyright © 2014 Elsevier España, S.L.U. y SEEIUC. All rights reserved.

  16. Increased ventilation in runners during running as compared to walking at similar metabolic rates.

    PubMed

    Berry, M J; Dunn, C J; Pittman, C L; Kerr, W C; Adair, N E

    1996-01-01

    At similar levels of carbon dioxide production (VCO2) and oxygen consumption (VO2), runners have been shown to have a greater minute ventilation (VE) during running as compared to walking. The mechanism responsible for these differences has yet to be identified. To determine if these differences are a result of differences in acid-base status, potassium (K+), norepinephrine and/or epinephrine levels, seven well-trained runners completed walk and run tests at similar VO2 and VCO2 levels. The occurrence of entrainment of the breathing and stride frequencies during both walking and running was also determined. VE was significantly greater during the run as compared to the walk, 73.7 (2.2) versus 68.6 (2.0) l.min-1, respectively, despite the similarity in VO2 and VCO2 levels. Alveolar ventilation was not significantly different between the run and the walk, 60.4 (4.7) versus 59.6 (4.4) l.min-1, respectively. Dead space ventilation was found to be significantly greater during running as compared to walking, 13.3 (3.2) versus 9.0 (4.7) l.min-1, respectively. The increases in VE were due to increases in breathing frequency and decreases in tidal volume during the run as compared to the walk. Arterial partial pressures of CO2 (PaCO2) were not significantly different when comparing walking and running to rest values nor when comparing walking and running. Arterial pH was significantly lower during walking as compared to rest and running. Bicarbonate levels were significantly lower during walking as compared to rest. Lactate was significantly greater during walking as compared to rest and to running. K+ levels were significantly higher during walking and running as compared to rest. Epinephrine and norepinephrine levels were not significantly different between running and walking. During the walk, six of the seven subjects entrained their breathing frequency to the stride frequency, and during the run three of the seven subjects demonstrated entrainment. Results from this

  17. Operative compared to non-operative treatment of displaced intra-articular calcaneal fractures

    PubMed Central

    Nouraei, Mohammad Hadi; Moosa, Farhad Mostafa

    2011-01-01

    BACKGROUND: The aim of this study was to compare outcomes of open reduction and rigid internal fixation of displaced calcaneal fractures with that of non operative treatment. METHODS: Seventy two consecutive patients with displaced intra-articular calcaneal fractures were selected regarding inclusive and exclusive criteria and then were randomly allocated to surgical and non surgical groups. First group underwent open reduction and internal fixation with reconstruction plate and screws fixation and the other group were treated with closed reduction and cast immobilization. Data were collected by clinical observation and a check list. Data was analyzed by chi-square and student's t-test. RESULTS: The results showed significant difference between outcomes of surgical treatment and nonsurgical method (p = 0.001). There were some differences between two methods in terms of decreasing pain [Odd Ratio (OR): 6.72, p = 0.001], swelling (OR: 6.80, p = 0.001), increased range of motion of the joints (p = 0.001), decreased late osteoarthritis (OR: 2.33, p = 0.22) in favor of surgical group. CONCLUSIONS: Open reduction and internal fixation of displaced calcaneal fractures in absence of open fracture, severe osteoporosis, or comminution, poor general condition may be the preferred method of treatment. PMID:22279476

  18. A Novel Prototype Neonatal Resuscitator That Controls Tidal Volume and Ventilation Rate: A Comparative Study of Mask Ventilation in a Newborn Manikin

    PubMed Central

    Solevåg, Anne Lee; Haemmerle, Enrico; van Os, Sylvia; Bach, Katinka P.; Cheung, Po-Yin; Schmölzer, Georg M.

    2016-01-01

    The objective of this randomized controlled manikin trial was to examine tidal volume (VT) delivery and ventilation rate during mask positive pressure ventilation (PPV) with five different devices, including a volume-controlled prototype Next Step™ device for neonatal resuscitation. We hypothesized that VT and rate would be closest to target with the Next Step™. Twenty-five Neonatal Resuscitation Program providers provided mask PPV to a newborn manikin (simulated weight 1 kg) in a randomized order with a self-inflating bag (SIB), a disposable T-piece, a non-disposable T-piece, a stand-alone resuscitation system T-piece, and the Next Step™. All T-pieces used a peak inflation pressure of 20 cmH2O and a positive end-expiratory pressure of 5 cmH2O. The participants were instructed to deliver a 5 mL/kg VT (rate 40–60/min) for 1 min with each device and each of three test lungs with increasing compliance of 0.5, 1.0, and 2.0 mL/cmH2O. VT and ventilation rate were compared between devices and compliance levels (linear mixed model). All devices, except the Next Step™ delivered a too high VT, up to sixfold the target at the 2.0-mL/cmH2O compliance. The Next Step™ VT was 26% lower than the target in the low compliance. The ventilation rate was within target with the Next Step™ and SIB, and slightly lower with the T-pieces. In conclusion, routinely used newborn resuscitators over delivered VT, whereas the Next Step™ under delivered in the low compliant test lung. The SIB had higher VT and rate than the T-pieces. More research is needed on volume-controlled delivery room ventilation. PMID:27965949

  19. A prospective, randomized, double-blind, multicenter study comparing remifentanil with fentanyl in mechanically ventilated patients.

    PubMed

    Spies, Claudia; Macguill, Martin; Heymann, Anja; Ganea, Christina; Krahne, Daniel; Assman, Angelika; Kosiek, Heinrich-Rudolf; Scholtz, Kathrin; Wernecke, Klaus-Dieter; Martin, Jörg

    2011-03-01

    To compare the quality of analgesia provided by a remifentanil-based analgesia regime with that provided by a fentanyl-based regime in critically ill patients. This was a registered, prospective, two-center, randomized, triple-blind study involving adult medical and surgical patients requiring mechanical ventilation (MV) for more than 24 h. Patients were randomized to either remifentanil infusion or a fentanyl infusion for a maximum of 30 days. Sedation was provided using propofol (and/or midazolam if required). Primary outcome was the proportion of patients in each group maintaining a target analgesia score at all time points. Secondary outcomes included duration of MV, discharge times, and morbidity. At planned interim analysis (n = 60), 50% of remifentanil patients (n = 28) and 63% of fentanyl patients (n = 32) had maintained target analgesia scores at all time points (p = 0.44). There were no significant differences between the groups with respect to mean duration of ventilation (135 vs. 165 h, p = 0.80), duration of hospital stay, morbidity, or weaning. Interim analysis strongly suggested futility and the trial was stopped. The use of remifentanil-based analgesia in critically ill patients was not superior regarding the achievement and maintenance of sufficient analgesia compared with fentanyl-based analgesia.

  20. Electrical impedance tomography compared to positron emission tomography for the measurement of regional lung ventilation: an experimental study

    PubMed Central

    Richard, JC; Pouzot, C; Gros, A; Tourevieille, C; Lebars, D; Lavenne, F; Frerichs, I; Guérin, C

    2009-01-01

    Introduction Electrical impedance tomography (EIT), which can assess regional lung ventilation at the bedside, has never been compared with positron-emission tomography (PET), a gold-standard to quantify regional ventilation. This experiment systematically compared both techniques in injured and non-injured lungs. Methods The study was performed in six mechanically ventilated female piglets. In normal lungs, tidal volume (VT) was randomly changed to 6, 8, 10 and 15 ml/kg on zero end-expiratory pressure (ZEEP), then, at VT 10 ml/kg, positive end-expiratory pressure (PEEP) was randomly changed to 5, 10 and 15 cmH2O. Afterwards, acute lung injury (ALI) was subsequently created in three animals by injecting 3 ml/kg hydrochloric acid into the trachea. Then at PEEP 5 cmH2O, VT was randomly changed to 8 and 12 ml/kg and PEEP of 10 and 15 cmH2O applied at VT 10 ml/kg. EIT and PET examinations were performed simultaneously. EIT ventilation (VTEIT) and lung volume (VL) were measured in the anterior and posterior area of each lung. On the same regions of interest, ventilation (VPET) and aerated lung volume (VAatten) were determined with PET. Results On ZEEP, VTEIT and VPET significantly correlated for global (VTEIT = VPET - 2E-13, R2 = 0.95, P < 0.001) and regional (VTEIT = 0.81VPET+7.65, R2 = 0.63, P < 0.001) ventilation over both conditions. For ALI condition, corresponding R2 were 0.91 and 0.73 (P < 0.01). Bias was = 0 and limits of agreement were -37.42 and +37.42 ml/min for global ventilation over both conditions. These values were 0.04 and -29.01 and +29.08 ml/min, respectively, for regional ventilation. Significant correlations were also found between VL and VAatten for global (VL = VAatten+1E-12, R2 = 0.93, P < 0.0001) and regional (VL = 0.99VAatten+0.92, R2 = 0.65, P < 0.001) volume. For ALI condition, corresponding R2 were 0.94 (P < 0.001) and 0.54 (P < 0.05). Bias was = 0 and limits of agreement ranged -38.16 and +38.16 ml for global ventilation over both

  1. Comparative Effectiveness of Noninvasive and Invasive Ventilation in Critically Ill Patients with Acute Exacerbation of COPD

    PubMed Central

    Stefan, Mihaela S.; Nathanson, Brian H.; Higgins, Thomas L.; Steingrub, Jay S.; Lagu, Tara; Rothberg, Michael B.; Lindenauer, Peter K.

    2015-01-01

    Objective To compare the characteristics and hospital outcomes of patients with an acute exacerbation of chronic obstructive lung disease (COPD) treated in the ICU with initial noninvasive (NIV) or invasive mechanical ventilation (IMV). Design Retrospective, multicenter cohort studyof prospectively collected data. We used propensity matching to compare the outcomes of patients treated with NIV to those treated with IMV. We also assessed predictors for NIV failure. Setting Thirty-eight hospitals participating in the Acute Physiology and Chronic Health Evaluation (APACHE) database from 2008 through 2012. Subjects A total of 3,520 with a diagnosis of COPD exacerbation including 27.7% who received NIV and 45.5% who received IMV. Measurements and Main Results NIV failure was recorded in 13.7% from patients ventilated noninvasively. Hospital mortality was 7.4% for patients treated with NIV; 16.1% for those treated with IMV; and 22.5% for those who failed NIV. In the propensity matched analysis, patients initially treated with NIV had a 41% lower risk of death compared with those treated with IMV (RR: 0.59, 95% CI 0.36, 0.97). Factors that were independently associated with NIV failure were SAPS-II score (relative risk = 1.04 per point increase, 95% CI: 1.03, 1.04) and the presence of cancer (2.29, 95% CI: 0.96, 5.45). Conclusions Among critically ill adults with COPD exacerbation, the receipt of NIV was associated with a lower risk of in-hospital mortality compared to IMV; NIV failure was associated with the worst outcomes. These results support the use NIV as a first line therapy in appropriately selected critically ill patients with COPD while also highlighting the risks associated with NIV failure and the need to be cautious in the face of severe disease. PMID:25768682

  2. Comparing fixation used for calcaneal displacement osteotomies: a look at removal rates and cost.

    PubMed

    Lucas, Douglas E; Simpson, G Alex; Philbin, Terrence M

    2015-02-01

    The calcaneal displacement osteotomy is a procedure frequently used by foot and ankle surgeons for hindfoot angular deformity. Traditional techniques use compression screw fixation that can result in prominent hardware. While the results of the procedure are generally good, a common concern is the development of plantar heel pain related to prominent hardware. The primary purpose of this study is to retrospectively compare clinical outcomes of 2 fixation methods for the osteotomy. Secondarily a cost analysis will compare implant costs to hardware removal costs. Records were reviewed for patients who had undergone a calcaneal displacement osteotomy fixated with either lag screw or a locked lateral compression plate (LLCP). Neuropathy, previous ipsilateral calcaneus surgery, heel pad trauma, or incomplete radiographic follow-up were exclusionary. Thirty-two patients (19.4%) required hardware removal from the screw fixation group compared to 1 (1.6%) of the LLCP group, which is significant (P < .05). Time to radiographic healing was not significantly different (P = .87). The screw fixation group required more follow-up visits over a longer period of time (P < .05). Implant cost was remarkably different with screw fixation costing on average $247.12, compared to the LLCP costing $1175.59. Although the LLCP cost was significantly higher, cost savings were identified when the cost of removal and removal rates were included. This study demonstrates that this device provides adequate stabilization for healing in equivalent time to screw fixation. The LLCP required decreased rates of hardware removal with fewer postoperative visits over a shorter period of time. Significant savings were demonstrated in the LLCP group despite the higher implant cost. Therapeutic, Level III, Retrospective Comparative Study. © 2014 The Author(s).

  3. Dynamic high-resolution sonography compared to magnetic resonance imaging for diagnosis of temporomandibular joint disk displacement.

    PubMed

    Habashi, Hadeel; Eran, Ayelet; Blumenfeld, Israel; Gaitini, Diana

    2015-01-01

    The purpose of this study was to determine the value of dynamic high-resolution sonography for evaluation of temporomandibular joint (TMJ) disk displacement compared to magnetic resonance imaging (MRI) with the mouth closed and during the maximal mandibular range of motion. Dynamic high-resolution sonography with the mouth closed and during the maximal mandibular range of motion was performed on 39 consecutive patients (78 joints; 13 male and 26 female; age range, 18-77 years; mean age ± SD, 37.23 ± 16.26 years) with TMJ disorders. A TMJ MRI study was performed 1 to 7 days after sonography. We searched for signs of disk displacement and findings compatible with degenerative joint disease. Both studies were performed and interpreted independently by blinded operators. Magnetic resonance imaging depicted 22 normal joints (28.2%), 21 (26.9%) with anterior disk displacement with reduction, 15 (19.2%) with anterior disk displacement without reduction, and 20 (25.6%) with degenerative disease. Sonography depicted 30 normal joints (38.5%), 22 (28.2%) with anterior disk displacement with reduction, 12 (15.4%) with anterior disk displacement without reduction, and 14 (17.9%) with degenerative disease. The overall sensitivity, specificity, and accuracy of sonography for diagnosis of disk displacement were 74.3%, 84.2%, and 77.7%, respectively. The sensitivity, specificity, and accuracy for diagnosis of disk displacement with reduction were 78.6%, 66.7%, and 73.0%, and the values for diagnosis of disk displacement without reduction were 66.7%, 78.6%, and 73.0%. Dynamic high-resolution sonography is a potential imaging method for diagnosis of TMJ disk displacement and degenerative diseases. Further studies are needed to make dynamic high-resolution sonography the first-line test for diagnosis of TMJ disk displacement. © 2015 by the American Institute of Ultrasound in Medicine.

  4. Two Types of Ventilated Porometers Compared on Broadleaf and Coniferous Species 12

    PubMed Central

    Johnson, Jon D.

    1981-01-01

    Two ventilated porometers (diffusion and steady-state) were compared on four broadleaf and five coniferous species. The diffusion porometer gave consistently lower conductance values for both types of species, reflecting a direct stomatal response to low chamber humidity. At high conductance values, the porometers produced a linear and nearly equal response, but the diffusion porometer was less sensitive at low conductance values. This was due to lower air flow (20% of the velocity in the steady-state porometer) and water vapor sorption (by its acrylic plastic chamber). The broadleaf species had less variation (R2 = 0.81) than did the coniferous species (R2 = 0.61), but, with the latter, there was better correspondence between the two porometers, possibly due to sampling technique. Conductance values were clustered by species. PMID:16661946

  5. The comparative performance of Roots type aircraft engine superchargers as affected by change in impeller speed and displacement

    NASA Technical Reports Server (NTRS)

    Ware, Marsden; Wilson, Ernest E

    1929-01-01

    This report presents the results of tests made on three sizes of roots type aircraft engine superchargers. The impeller contours and diameters of these machines were the same, but the length were 11, 8 1/4, and 4 inches, giving displacements of 0.509, 0.382, and 0.185 cubic foot per impeller revolution. The information obtained serves as a basis for the examination of the individual effects of impeller speed and displacement on performance and of the comparative performance when speed and displacement are altered simultaneously to meet definite service requirements. According to simple theory, when assuming no losses, the air weight handled and the power required for a given pressure difference are directly proportional to the speed and the displacement. These simple relations are altered considerably by the losses. When comparing the performance of different sizes of machines whose impeller speeds are so related that the same service requirements are met, it is found that the individual effects of speed and displacement are canceled to a large extent, and the only considerable difference is the difference in the power losses which decrease with increase in the displacement and the accompanying decrease in speed. This difference is small in relation to the net power of the engine supercharger unit, so that a supercharger with short impellers may be used in those applications where the space available is very limited with any considerable sacrifice in performance.

  6. Comparing DXA and Air-Displacement-Plethysmography to Assess Body Composition of Male Collegiate Hockey Players.

    PubMed

    Delisle-Houde, Patrick; Reid, Ryan E R; Insogna, Jessica A; Prokop, Neal W; Buchan, Tayler A; Fontaine, Shawn L; Andersen, Ross E

    2017-02-15

    Accurate assessment of body composition is an important consideration for athletes as it is a health/performance variable. However, little is known about the variability in values obtained across different assessment methods for specific athlete populations. The purpose of this study was to compare two common laboratory methods that assess body composition: air displacement plethysmography (BOD POD™) and dual energy x-ray absorptiometry (DXA). Twenty-nine male collegiate hockey players, (Age = 24.07 ± 1.49, BMI = 26.5 ± 2.74) participated in this study. All participants underwent back-to-back BOD POD™ and DXA evaluations. Paired t-tests and Bland-Altman analyses were performed to compare differences in fat mass, fat percentage, and fat-free mass between methods. Average fat percentage reported by the DXA and BOD POD™ was 15.34 ± 3.53 and 11.66 ± 4.82 respectively, resulting in a bias score of 3.78 ± 2.33 kg (t(28) = 8.71, p ≤ 0.001). Average fat mass reported by the DXA and BOD POD™ was 13.42 ± 3.59 and 10.15 ± 4.54 kg respectively, resulting in a bias score of 3.27 ± 1.92 kg (t(28) = 9.18, p ≤ 0.001). Average fat-free mass reported by the DXA and BOD POD™ was 73.31 ± 5.30 and 76.25 ± 5.74 kg respectively, resulting in a bias score of -2.93 ± 2.06 kg (t(28) = -7.66, p ≤ 0.001). Our findings can help make more insightful comparisons between studies that use different body composition methodologies amongst athletic populations.

  7. Ventilation Model

    SciTech Connect

    V. Chipman

    2002-10-05

    The purpose of the Ventilation Model is to simulate the heat transfer processes in and around waste emplacement drifts during periods of forced ventilation. The model evaluates the effects of emplacement drift ventilation on the thermal conditions in the emplacement drifts and surrounding rock mass, and calculates the heat removal by ventilation as a measure of the viability of ventilation to delay the onset of peak repository temperature and reduce its magnitude. The heat removal by ventilation is temporally and spatially dependent, and is expressed as the fraction of heat carried away by the ventilation air compared to the fraction of heat produced by radionuclide decay. One minus the heat removal is called the wall heat fraction, or the remaining amount of heat that is transferred via conduction to the surrounding rock mass. Downstream models, such as the ''Multiscale Thermohydrologic Model'' (BSC 2001), use the wall heat fractions as outputted from the Ventilation Model to initialize their post-closure analyses. The Ventilation Model report was initially developed to analyze the effects of preclosure continuous ventilation in the Engineered Barrier System (EBS) emplacement drifts, and to provide heat removal data to support EBS design. Revision 00 of the Ventilation Model included documentation of the modeling results from the ANSYS-based heat transfer model. The purposes of Revision 01 of the Ventilation Model are: (1) To validate the conceptual model for preclosure ventilation of emplacement drifts and verify its numerical application in accordance with new procedural requirements as outlined in AP-SIII-10Q, Models (Section 7.0). (2) To satisfy technical issues posed in KTI agreement RDTME 3.14 (Reamer and Williams 2001a). Specifically to demonstrate, with respect to the ANSYS ventilation model, the adequacy of the discretization (Section 6.2.3.1), and the downstream applicability of the model results (i.e. wall heat fractions) to initialize post

  8. Comparative transduction mechanisms of hair cells in the bullfrog uticulus. 2: Sensitivity and response dynamics to hair bundle displacement

    NASA Technical Reports Server (NTRS)

    Baird, Richard A.

    1994-01-01

    voltage responses of individual hair cells were compared to both hair bundle displacement and intracellular current.

  9. 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.

  10. Body density estimates from upper-body skinfold thicknesses compared to air-displacement plethysmography.

    PubMed

    Shafer, Kimberly J; Siders, William A; Johnson, LuAnn K; Lukaski, Henry C

    2010-04-01

    Determine the accuracy of body density (Db) estimated with upper-body skinfold thickness (SFT) measurements compared to air-displacement plethysmography (ADP) and ascertain whether body mass index (BMI) impacts the accuracy of SFT to assess Db. We estimated Db with SFT and ADP in 131 healthy men and women with normal (N; 18.5-24.9kg/m(2)), overweight (OW; 25-29.9kg/m(2)), and obese (OB; 30-39.9kg/m(2)) BMI. Compared with ADP, SFT overestimated (p<0.05) Db in OW and OB females and in OB males (-0.0047, -0.0164 and -0.0119g/cc, respectively), and underestimated (p<0.05) Db in N females and males (0.0050 and 0.0068g/cc, respectively) but did not differently estimate Db in OW males. The gender by BMI group interaction was not significant. SFT underestimated (p<0.05; 0.0058g/cc) Db in the N and overestimated (p<0.05; 0.0113g/cc) Db in the OB BMI groups. The error in predicting Db did not change significantly over the range of Db within the N (r=0.239, p=0.06) and OB (r=0.160, p=0.934) BMI groups. Limits of agreement were -0.0165 to 0.0284g/cc and -0.0365 to 0.0085g/cc for the N and OB BMI groups, respectively. The error of estimating Db with SFT was correlated with mean Db in the aggregate sample (r=0.495, p<0.0001) and the OW group (r=0.394, p<0.009). The regression-based limits of agreement were +/-0.0226g/cc in the total group and +/-0.0168g/cc in the OW group. Although SFT offer practical advantages, the validity of SFT to estimate Db among individuals with N and OB BMI is adversely affected. Copyright 2009. Published by Elsevier Ltd.

  11. Ventilator-CPAP with the Siemens Servo 900C compared with continuous flow-CPAP in intubated patients: effect on work of breathing.

    PubMed

    Aerts, J G; van den Berg, B; Bogaard, J M

    1997-10-01

    The effects of continuous positive airway pressure (CPAP) provided by the Siemens Servo 900C ventilator were compared with a continuous flow system (CF-CPAP) in patients weaning from the ventilator. Thirteen patients were studied using both systems at a CPAP level of 0.5 kPa. Additional work of breathing (Wapp) and derived variables were determined in relation to the minute volumes of the patients. The Wapp imposed by the ventilator exceeded the Wapp of CF-CPAP in all patients. The difference in Wapp between ventilator- and CF-CPAP was greater at higher ventilatory needs. The increments in Wapp imposed by the ventilator were positively correlated with the actual end-expiratory pressures (EEP). The EEP increasingly exceeded the preset CPAP level of the ventilator at higher minute volumes. An inspiratory threshold due to a gradient between EEP and preset CPAP greatly increased the Wapp imposed by the ventilator. As this threshold was attributed to the resistance of the PEEP device of the ventilator, it indicates that the additional work related to the expiratory value should be taken into account when the Siemens Servo 900C ventilator is used for weaning purposes.

  12. A comparative study of behaviors of ventilated supercavities between experimental models with different mounting configurations

    NASA Astrophysics Data System (ADS)

    Lee, Seung-Jae; Kawakami, Ellison; Karn, Ashish; Arndt, Roger E. A.

    2016-08-01

    Small-scale water tunnel experiments of the phenomenon of supercavitation can be carried out broadly using two different kinds of experimental models-in the first model (forward facing model, or FFM), the incoming flow first interacts with the cavitator at front, which is connected to the strut through a ventilation pipe. The second model could have the strut and the ventilation pipe preceding the cavitator (backward facing model, or BFM). This is the continuation of a water tunnel study of the effects of unsteady flows on axisymmetric supercavities. In this study, the unwanted effect of test model configuration on supercavity shape in periodic flows was explored through a comparison of FFM and BFM models. In our experiments, it was found that periodic gust flows have only a minimal effect on the maximum diameter and the cavity length can be shortened above a certain vertical velocity of periodic flows. These findings appear to be robust regardless of the model configuration.

  13. Effects of low oxygen dead space ventilation and breath-holding test in evaluating cerebrovascular reactivity: A comparative observation.

    PubMed

    Ju, Ke-Ju; Zhong, Ling-Ling; Ni, Xiao-Yu; Xia, Lei; Xue, Liu-Jun; Cheng, Guan-Liang

    2017-01-01

    This study aims to explore the application prospect of low oxygen dead space ventilation (LODSV) in evaluating vasomotor reactivity (VMR) by comparison between LODSV and breath-holding test (BHT). Outpatient or inpatient patients who underwent transcranial Doppler sonography (TCD) were enrolled into this study. These patients successively underwent BHT and LODSV. The cooperation degree, tolerance conditions and adverse reactions in patients were recorded, and VMR was calculated, compared and analyzed. Patients had poor cooperation during BHT. Except for compensatory tachypnea after BHT, patients basically had no adverse reaction. The main manifestations of patients undergoing LODSV were deepened breathing and accelerated frequency in the end of the ventilation, and increased heart rate and a slight decline in pulse oxygen that rapidly recovered after ventilation. The increase rate of blood flow velocity in patients undergoing LODSV was significantly higher than in BHT (P<0.001), and its calculated VMR value was approximately 15% higher than BHT (P<0.001). BHT revealed a monophasic curve that slightly descends and rapidly increases, and LODSV revealed a curve that descends for a short time and slowly increases with a platform. LODSV can effectively eliminate the affect of poor cooperation in patients, and avoid intolerance caused by hypoxia. Hence, VMR value is more accurate than that determined by BHT; and this can reflect the maximum reaction ability of the blood vessels. Therefore, this method has higher clinical application value.

  14. Internal screw fixation compared with bipolar hemiarthroplasty for treatment of displaced femoral neck fractures in elderly patients.

    PubMed

    Gjertsen, J-E; Vinje, T; Engesaeter, L B; Lie, S A; Havelin, L I; Furnes, O; Fevang, J M

    2010-03-01

    Internal fixation and arthroplasty are the two main options for the treatment of displaced femoral neck fractures in the elderly. The optimal treatment remains controversial. Using data from the Norwegian Hip Fracture Register, we compared the results of hemiarthroplasty and internal screw fixation in displaced femoral neck fractures. Data from 4335 patients over seventy years of age who had internal fixation (1823 patients) or hemiarthroplasty (2512 patients) to treat a displaced femoral neck fracture were compared at a minimum follow-up interval of twelve months. One-year mortality, the number of reoperations, and patient self-assessment of pain, satisfaction, and quality of life at four and twelve months were analyzed. Subanalyses of patients with cognitive impairment and reduced walking ability were done. In the arthroplasty group, only contemporary bipolar prostheses were used and uncemented prostheses with modern stems and hydroxyapatite coating accounted for 20.8% (522) of the implants. There were no differences in one-year mortality (27% in the osteosynthesis group and 25% in the arthroplasty group; p = 0.76). There were 412 reoperations (22.6%) performed in the osteosynthesis group and seventy-two (2.9%) in the hemiarthroplasty group during the follow-up period. After twelve months, the osteosynthesis group reported more pain (mean score, 29.9 compared with 19.2), higher dissatisfaction with the operation result (mean score, 38.9 compared with 25.7), and a lower quality of life (mean score, 0.51 compared with 0.60) than the arthroplasty group. All differences were significant (p < 0.001). For patients with cognitive impairment, hemiarthroplasty provided a better functional outcome (less pain, higher satisfaction with the result of the operation, and higher quality of life as measured on the EuroQol visual analog scale) at twelve months (p < 0.05). Displaced femoral neck fractures in the elderly should be treated with hemiarthroplasty.

  15. VENTILATION MODEL REPORT

    SciTech Connect

    V. Chipman

    2002-10-31

    The purpose of the Ventilation Model is to simulate the heat transfer processes in and around waste emplacement drifts during periods of forced ventilation. The model evaluates the effects of emplacement drift ventilation on the thermal conditions in the emplacement drifts and surrounding rock mass, and calculates the heat removal by ventilation as a measure of the viability of ventilation to delay the onset of peak repository temperature and reduce its magnitude. The heat removal by ventilation is temporally and spatially dependent, and is expressed as the fraction of heat carried away by the ventilation air compared to the fraction of heat produced by radionuclide decay. One minus the heat removal is called the wall heat fraction, or the remaining amount of heat that is transferred via conduction to the surrounding rock mass. Downstream models, such as the ''Multiscale Thermohydrologic Model'' (BSC 2001), use the wall heat fractions as outputted from the Ventilation Model to initialize their postclosure analyses.

  16. Whole body air displacement plethysmography compared with hydrodensitometry for body composition analysis.

    PubMed

    Dewit, O; Fuller, N J; Fewtrell, M S; Elia, M; Wells, J C

    2000-02-01

    To assess the acceptability and feasibility of whole body air displacement plethysmography in children and to determine its precision and agreement with hydrodensitometry, an appropriate reference method. Age specific two component model equations were used to predict fat mass from body density in 22 children aged 8-12 years and in 10 adults for comparison of methods. Precision for each method was established from duplicate measurements. Plethysmography was accepted more readily than hydrodensitometry (100% v 69% provided duplicate measurements). Precision for fat mass in children was 0.38 kg by plethysmography and 0.68 kg by hydrodensitometry, and results were similar in adults. The mean (SD) fat mass in children was 6.9 kg (4.0) and 6.7 kg (4. 2) by plethysmography and hydrodensitometry, respectively, but 95% limits of agreement between methods were large (-4.1 kg to 3.5 kg fat). Plethysmography was more readily accepted and had better precision than hydrodensitometry. It also provided similar body composition results for the group but not for all individual children.

  17. Whole body air displacement plethysmography compared with hydrodensitometry for body composition analysis

    PubMed Central

    Dewit, O.; Fuller, N; Fewtrell, M.; Elia, M; Wells, J

    2000-01-01

    AIMS—To assess the acceptability and feasibility of whole body air displacement plethysmography in children and to determine its precision and agreement with hydrodensitometry, an appropriate reference method.
METHODS—Age specific two component model equations were used to predict fat mass from body density in 22 children aged 8-12 years and in 10 adults for comparison of methods. Precision for each method was established from duplicate measurements.
RESULTS—Plethysmography was accepted more readily than hydrodensitometry (100% v 69% provided duplicate measurements). Precision for fat mass in children was 0.38 kg by plethysmography and 0.68 kg by hydrodensitometry, and results were similar in adults. The mean (SD) fat mass in children was 6.9 kg (4.0) and 6.7 kg (4.2) by plethysmography and hydrodensitometry, respectively, but 95% limits of agreement between methods were large (−4.1 kg to 3.5 kg fat).
CONCLUSION—Plethysmography was more readily accepted and had better precision than hydrodensitometry. It also provided similar body composition results for the group but not for all individual children.

 PMID:10648375

  18. Anaesthesia ventilators

    PubMed Central

    Jain, Rajnish K; Swaminathan, Srinivasan

    2013-01-01

    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. PMID:24249886

  19. 49 CFR 24.204 - Availability of comparable replacement dwelling before displacement.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... the person. When possible, three or more comparable replacement dwellings shall be made available. A... any case where it is demonstrated that a person must move because of: (1) A major disaster as defined...

  20. Outcomes after fixation for undisplaced femoral neck fracture compared to hemiarthroplasty for displaced femoral neck fracture among the elderly.

    PubMed

    Lin, Jeff Chien-Fu; Liang, Wen-Miin

    2015-08-19

    This study compared the rates of mortality, medical complication, and reoperation after fixation surgery for displaced femoral neck fracture with those after hemiarthroplasty surgery for undisplaced femoral neck fracture using competing risk analysis in inpatients aged 60 years and above from a population database in Taiwan. We identified 13,772 subjects who underwent fixation for undisplaced cervical fracture and 13,772 matched controls who underwent hemiarthroplasty for displaced cervical fracture from 1998 to 2007, and followed them up until the end of 2009. The outcomes of patients who received internal fixation for undisplaced fracture and those of patients who received hemiarthroplasty for displaced fracture were compared. The 3-month, 2-year, and 10-year mortality rates were 4.9%, 22.1%, and 67.1% for fixation, and 5.6%, 23.8%, and 71.0% for hemiarthroplasty, respectively. The 3-month, 2-year, and 10-year cumulative incidence rates of the first reoperation were 7.4%, 18.1%, and 27.7% for fixation and 6.3%, 12.0%, and 22.3% for hemiarthroplasty, respectively. The 3-month cumulative incidence rates of the first medical complication were 14.4% for fixation and 15.4% for hemiarthroplasty, respectively. Hemiarthroplasty had a 1.09 times (95% CI: 1.05-1.12) higher hazard ratio for overall death than fixation. However, fixation had a 1.36 times (95% CI: 1.29-1.43) higher subdistribution hazard ratio for first reoperation than hemiarthroplasty after adjusting for gender, age, and comorbidities. The short-term overall mortality and medical complication rate of fixation for undisplaced fracture were slightly lower than those of hemiarthroplasty for displaced fracture. However, the short-term cumulative incidence of first reoperation after fixation was significantly higher than that for hemiarthroplasty. Further prospective studies or clinical trials based on the competing risk model, and which include important risk factors, are necessary to quantify the adjusted

  1. Ventilation and oxygen consumption during acute hypoxia in newborn mammals: a comparative analysis.

    PubMed

    Mortola, J P; Rezzonico, R; Lanthier, C

    1989-10-01

    We asked whether the lack of sustained hyperventilation during acute hypoxia, often reported to occur in the infant, is a common characteristic among newborn mammalian species, and to which extent inter-species differences may be accounted for by differences in metabolic responses. Ventilation (VE) and breathing pattern have been measured by flow-plethysmography or by the barometric method in normoxia and after 10 min of 10% O2 breathing in newborn mammals of 17 species over a 3 g to 20 kg range in body size. In 14 of these species oxygen consumption (VO2) has also been measured by a manometric technique or by calculation from the changes in chamber O2 pressure. VE and VO2 changed in proportion, among species, both in normoxia and hypoxia. In hypoxia, VE was higher, similar, or even lower than in normoxia, with some relation to the degree of maturity of the species at birth. In general, the small or absent VE responses to hypoxia resulted from small or no increase in tidal volume, while breathing frequency stayed elevated. The few departures from this pattern could be explained by interspecies differences in hypoxic sensitivity, since additional experiments in kittens and puppies indicated that, with more severe hypoxia, the pattern changed from rapid and shallow to deep and slow. In all cases, irrespective of the magnitude of the VE response, the VE/VO2 (and the mean inspiratory flow/VO2) increased during hypoxia, because the drop in VE, when present, was accompanied by an even larger drop in VO2. In fact, VO2 in hypoxia decreased in most species, although to variable degrees. Body temperature either did not change or decreased slightly, possibly indicating a trend toward a decrease of the set point of thermoregulation during hypoxia. In conclusion, the analysis gave further support to the concept that, during acute hypoxia, changes in metabolic rate play a paramount role in the ventilatory response of the newborn mammal.

  2. Intravenous versus nebulized ceftazidime in ventilated piglets with and without experimental bronchopneumonia: comparative effects of helium and nitrogen.

    PubMed

    Tonnellier, Marc; Ferrari, Fabio; Goldstein, Ivan; Sartorius, Alfonso; Marquette, Charles-Hugo; Rouby, Jean-Jacques

    2005-05-01

    Lung deposition of intravenous cephalosporins is low. The lung deposition of equivalent doses of ceftazidime administered either intravenously or by ultrasonic nebulization using either nitrogen-oxygen or helium-oxygen as the carrying gas of the aerosol was compared in ventilated piglets with and without experimental bronchopneumonia. Five piglets with noninfected lungs and 5 piglets with Pseudomonas aeruginosa experimental bronchopneumonia received 33 mg/kg ceftazidime intravenously. Ten piglets with noninfected lungs and 10 others with experimental P. aeruginosa bronchopneumonia received 50 mg/kg ceftazidime by ultrasonic nebulization. In each group, the ventilator was operated in half of the animals with a 65%/35% helium-oxygen or nitrogen-oxygen mixture. Animals were killed, and multiple lung specimens were sampled for measuring ceftazidime lung tissue concentrations by high-performance liquid chromatography. As compared with intravenous administration, nebulization of ceftazidime significantly increased lung tissue concentrations (17 +/- 13 vs. 383 +/- 84 microg/g in noninfected piglets and 10 +/- 3 vs. 129 +/- 108 microg/g in piglets with experimental bronchopneumonia; P < 0.001). The use of a 65%/35% helium-oxygen mixture induced a 33% additional increase in lung tissue concentrations in noninfected piglets (576 +/- 141 microg/g; P < 0.001) and no significant change in infected piglets (111 +/- 104 microg/g). Nebulization of ceftazidime induced a 5- to 30-fold increase in lung tissue concentrations as compared with intravenous administration. Using a helium-oxygen mixture as the carrying gas of the aerosol induced a substantial additional increase in lung deposition in noninfected piglets but not in piglets with experimental bronchopneumonia.

  3. Inadequate statistical power of published comparative cohort studies on ventilator-associated pneumonia to detect mortality differences.

    PubMed

    Falagas, Matthew E; Kouranos, Vasilios D; Michalopoulos, Argyris; Rodopoulou, Sophia P; Athanasoulia, Anastasia P; Karageorgopoulos, Drosos E

    2010-02-15

    Comparative cohort studies are often conducted to identify novel therapeutic strategies or prognostic factors for ventilator-associated pneumonia (VAP). We aimed to evaluate the power of such studies to provide clinically and statistically significant conclusions with regard to mortality differences. We searched in PubMed and Scopus for comparative cohort studies that evaluated mortality in patients with VAP. We calculated the central estimates and corresponding 95% confidence intervals (CIs) for mortality differences between compared patient groups. We also calculated the statistical power of the included studies to detect a difference in mortality that corresponds to a risk ratio of 0.80. We identified 39 (20 prospective) comparative cohort studies on VAP as eligible for inclusion in this analysis. The median absolute risk difference in mortality between compared groups was 10% (interquartile range [IQR], 5%-18%), and the median width of the 95% CI of the absolute risk difference in mortality was 34% (IQR, 28%-42.5%). The median power of the included studies to detect a risk ratio for mortality of 0.80 was 14.7% (IQR, 10.6%-21.8%). There is considerable uncertainty around the central estimate of comparative cohort studies on VAP with regard to mortality differences. For a wiser use of resources allocated to research, we emphasize the need to conduct cohort studies with larger sample size so that potential differences between the compared groups are more likely to be shown.

  4. SU-E-J-120: Comparing 4D CT Computed Ventilation to Lung Function Measured with Hyperpolarized Xenon-129 MRI

    SciTech Connect

    Neal, B; Chen, Q

    2015-06-15

    Purpose: To correlate ventilation parameters computed from 4D CT to ventilation, profusion, and gas exchange measured with hyperpolarized Xenon-129 MRI for a set of lung cancer patients. Methods: Hyperpolarized Xe-129 MRI lung scans were acquired for lung cancer patients, before and after radiation therapy, measuring ventilation, perfusion, and gas exchange. In the standard clinical workflow, these patients also received 4D CT scans before treatment. Ventilation was computed from 4D CT using deformable image registration (DIR). All phases of the 4D CT scan were registered using a B-spline deformable registration. Ventilation at the voxel level was then computed for each phase based on a Jacobian volume expansion metric, yielding phase sorted ventilation images. Ventilation based upon 4D CT and Xe-129 MRI were co-registered, allowing qualitative visual comparison and qualitative comparison via the Pearson correlation coefficient. Results: Analysis shows a weak correlation between hyperpolarized Xe-129 MRI and 4D CT DIR ventilation, with a Pearson correlation coefficient of 0.17 to 0.22. Further work will refine the DIR parameters to optimize the correlation. The weak correlation could be due to the limitations of 4D CT, registration algorithms, or the Xe-129 MRI imaging. Continued development will refine parameters to optimize correlation. Conclusion: Current analysis yields a minimal correlation between 4D CT DIR and Xe-129 MRI ventilation. Funding provided by the 2014 George Amorino Pilot Grant in Radiation Oncology at the University of Virginia.

  5. Posterior tibial displacement in the PCL-deficient knee is reduced compared to the normal knee during gait.

    PubMed

    Orita, Naoya; Deie, Masataka; Shimada, Noboru; Iwaki, Daisuke; Asaeda, Makoto; Hirata, Kazuhiko; Ochi, Mitsuo

    2015-11-01

    Most individuals with an isolated posterior cruciate ligament (PCL) injury do not complain of disability even if posterior instability is objectively revealed by a static physical examination, such as the posterior drawer test. This suggests it is insufficient to only evaluate posterior instability under static conditions. Therefore, we have investigated the effect of isolated PCL injury on the detailed kinematics of the knee in a dynamic environment such as during gait. Eight unilateral PCL-deficient males and eight healthy control volunteers participated in this study. Isolated PCL injury was diagnosed by clinical examination. Stress X-ray imaging showed an average side-to-side difference of 12.7 ± 3.5 mm. Knee kinematics including anteroposterior tibial displacement were analysed during walking using the point cluster technique. Posterior tibial displacement from initial contact was significantly smaller during 9-22 % of the gait cycle by an average of 0.4 cm in the PCL group, compared to controls. In the PCL-deficient knee, the external rotational angle increased by an average of 3.3° at the loading response during 3-11 % of the gait cycle and the varus angle from initial contact increased by an average of 2.0° during 28-52 % of the gait cycle, compared to controls. Dynamic changes in the rotation and posterior translation patterns were seen after isolated PCL injury, suggesting the kinematics of PCL-deficient knees might be different to normal knees. These factors may contribute to long-term osteoarthritic change. Consequently, when choosing conservative treatment for PCL injury, these changes should be considered to prevent osteoarthritic change. III.

  6. A clinical, MRI, and EMG analysis comparing the efficacy of twin blocks and flat occlusal splints in the management of disc displacements with reduction.

    PubMed

    Rohida, Neeraj S; Bhad, Wasundhara

    2010-01-01

    Internal derangement of the temporomandibular joint (TMJ) is characterized by an abnormal disc-condyle relationship. Of all the various treatment modalities used in the management of disc displacements, flat occlusal and anterior repositioning splints are the most commonly used. Myofunctional appliances (such as bite-jumping appliances) are also advocated to treat anterior disc displacements. The present study compares the efficacy of twin blocks with conventional flat occlusal splints in patients with anterior disc displacement with reduction using clinical examination, MRI, and EMG. The sample consisted of 20 subjects between 12 and 20 years of age, who were randomly divided into two groups of 10 patients each: Group 1 was treated with twin blocks, while group 2 was treated using maxillary flat occlusal splints. The twin block is more effective in relieving joint pain, diminishing joint dysfunction, reducing joint clicking, and eliminating muscle tenderness in patients with anterior disc displacement with reduction as compared to the occlusal splint.

  7. Ventilation Model Report

    SciTech Connect

    V. Chipman; J. Case

    2002-12-20

    The purpose of the Ventilation Model is to simulate the heat transfer processes in and around waste emplacement drifts during periods of forced ventilation. The model evaluates the effects of emplacement drift ventilation on the thermal conditions in the emplacement drifts and surrounding rock mass, and calculates the heat removal by ventilation as a measure of the viability of ventilation to delay the onset of peak repository temperature and reduce its magnitude. The heat removal by ventilation is temporally and spatially dependent, and is expressed as the fraction of heat carried away by the ventilation air compared to the fraction of heat produced by radionuclide decay. One minus the heat removal is called the wall heat fraction, or the remaining amount of heat that is transferred via conduction to the surrounding rock mass. Downstream models, such as the ''Multiscale Thermohydrologic Model'' (BSC 2001), use the wall heat fractions as outputted from the Ventilation Model to initialize their post-closure analyses. The Ventilation Model report was initially developed to analyze the effects of preclosure continuous ventilation in the Engineered Barrier System (EBS) emplacement drifts, and to provide heat removal data to support EBS design. Revision 00 of the Ventilation Model included documentation of the modeling results from the ANSYS-based heat transfer model. Revision 01 ICN 01 included the results of the unqualified software code MULTIFLUX to assess the influence of moisture on the ventilation efficiency. The purposes of Revision 02 of the Ventilation Model are: (1) To validate the conceptual model for preclosure ventilation of emplacement drifts and verify its numerical application in accordance with new procedural requirements as outlined in AP-SIII-10Q, Models (Section 7.0). (2) To satisfy technical issues posed in KTI agreement RDTME 3.14 (Reamer and Williams 2001a). Specifically to demonstrate, with respect to the ANSYS ventilation model, the adequacy of

  8. An air curtain in the doorway of a ventilated space

    NASA Astrophysics Data System (ADS)

    Frank, Daria; Linden, Paul

    2013-11-01

    Air curtains are used to reduce the heat and the mass exchange between the indoor environment and the ambient. Their sealing ability is assessed in terms of the effectiveness E, the fraction of the exchange flow prevented by the air curtain compared to the open-door situation. Previous work studied the air curtain effectiveness when the doorway is the only means of ventilating a space. In this talk we examine effects of an additional displacement ventilation pathway on the effectiveness. The main controlling parameter is the deflection modulus Dm which is the ratio between the momentum flux of the air curtain and the transverse forces due to the displacement ventilation. For small values of Dm the air curtain is drawn inside the space by the ventilation flow. For high values of Dm the flow is controlled by the air curtain. A smooth transition occurs between these two regimes and we estimate the Dm value for the onset of this transition. Our model makes a quantitative prediction of E (Dm) in the ventilation-driven regime, and explains qualitatively the shape of the curve in the other two regimes. Laboratory experiments were conducted to test the proposed model. The experimental data were compared to theoretical predictions and good agreement was found.

  9. Noninvasive ventilation in trauma

    PubMed Central

    Karcz, Marcin K; Papadakos, Peter J

    2015-01-01

    Trauma patients are a diverse population with heterogeneous needs for ventilatory support. This requirement depends mainly on the severity of their ventilatory dysfunction, degree of deterioration in gaseous exchange, any associated injuries, and the individual feasibility of potentially using a noninvasive ventilation approach. Noninvasive ventilation may reduce the need to intubate patients with trauma-related hypoxemia. It is well-known that these patients are at increased risk to develop hypoxemic respiratory failure which may or may not be associated with hypercapnia. Hypoxemia in these patients is due to ventilation perfusion mismatching and right to left shunt because of lung contusion, atelectasis, an inability to clear secretions as well as pneumothorax and/or hemothorax, all of which are common in trauma patients. Noninvasive ventilation has been tried in these patients in order to avoid the complications related to endotracheal intubation, mainly ventilator-associated pneumonia. The potential usefulness of noninvasive ventilation in the ventilatory management of trauma patients, though reported in various studies, has not been sufficiently investigated on a large scale. According to the British Thoracic Society guidelines, the indications and efficacy of noninvasive ventilation treatment in respiratory distress induced by trauma have thus far been inconsistent and merely received a low grade recommendation. In this review paper, we analyse and compare the results of various studies in which noninvasive ventilation was applied and discuss the role and efficacy of this ventilator modality in trauma. PMID:25685722

  10. Ventilation efficiencies and thermal comfort results of a desk-edge-mounted task ventilation system

    SciTech Connect

    Faulkner, D.; Fisk, W.J.; Sullivan, D.P.; Lee, S.M.

    2003-09-01

    In chamber experiments, we investigated the ventilation effectiveness and thermal comfort of a task ventilation system with an air supply nozzle located underneath the front edge of a desk and directing air toward a heated mannequin or a human volunteer seated at the desk. The task ventilation system provided outside air, while another ventilation system provided additional space cooling but no outside air. Test variables included the vertical angle of air supply (-15{sup o} to 45{sup o} from horizontal), and the supply flow rate of (3.5 to 6.5 L s{sup -1}). Using the tracer gas step-up and step-down procedures, the measured air change effectiveness (i.e., exhaust air age divided by age of air in the breathing zone) in experiments with the mannequin ranged from 1.4 to 2.7 (median, 1.8), whereas with human subjects the air change effectiveness ranged from 1.3 to 2.3 (median, 1.6). The majority of the air change effectiveness values with the human subjects were less than values with the mannequin at comparable tests. Similarly, the tests run with supply air temperature equal to the room air temperature had lower air change effectiveness values than comparable tests with the supply air temperature lower ({approx}5 C) than the room air temperature. The air change effectiveness values are higher than typically reported for commercially available task ventilation or displacement ventilation systems. Based on surveys completed by the subjects, operation of the task ventilation system did not cause thermal discomfort.

  11. Anterior-Inferior Plating Results in Fewer Secondary Interventions Compared to Superior Plating for Acute Displaced Midshaft Clavicle Fractures.

    PubMed

    Serrano, Rafael; Borade, Amrut; Mir, Hassan; Shah, Anjan; Watson, David; Infante, Anthony; Frankle, Mark A; Mighell, Mark A; Sagi, H Claude; Horwitz, Daniel S; Sanders, Roy W

    2017-09-01

    To determine whether a difference in plate position for fixation of acute, displaced, midshaft clavicle fractures would affect the rate of secondary intervention. Retrospective Comparative Study. Two academic Level 1 Regional Trauma Centers. Five hundred ten patients treated surgically for an acutely displaced midshaft clavicle fracture between 2000 and 2013 were identified and reviewed retrospectively at a minimum of 24 months follow-up (F/U). Fractures were divided into 2 cohorts, according to plate position: Anterior-Inferior (AI) or Superior (S). Exclusion criteria included age <16 years, incomplete data records, and loss to F/U. Group analysis included demographics (age, sex, body mass index), fracture characteristics (mechanism of injury, open or closed), hand dominance, ipsilateral injuries, time between injury to surgery, time to radiographic union, length of F/U, and frequency of secondary procedures. Patients were treated either with AI or S clavicle plating at the treating surgeon's discretion. Rate and reason for secondary intervention. Fisher exact test, t test. and odds ratio were used for statistical analysis. Final analysis included 252 fractures/251 patients. One hundred eighteen (47%) were in group AI; 134 (53%) were in group S. No differences in demographics, fracture characteristics, time to surgery, time to union, or length of F/U existed between groups. Seven patients/7 fractures (5.9%) in Group AI underwent a secondary surgery whereas 30 patients/30 fractures (22.3%) in group S required a secondary surgery. An additional intervention secondary to superior plate placement was highly statistically significant (P < 0.001). Furthermore, because 80% of these subsequent interventions were a result of plate irritation with patient discomfort, the odds ratio for a second procedure was 5 times greater in those fractures treated with a superior plate. This comparative analysis indicates that AI plating of midshaft clavicle fractures seems to lessen

  12. High Tidal Volume Decreases ARDS, Atelectasis, and Ventilator Days Compared to Low Tidal Volume in Pediatric Burned Patients with Inhalation Injury

    PubMed Central

    Sousse, Linda E; Herndon, David N; Andersen, Clark R; Ali, Arham; Benjamin, Nicole C; Granchi, Thomas; Suman, Oscar E; Mlcak, Ronald P

    2015-01-01

    Background Inhalation injury, which is among the causes of acute lung injury and acute respiratory distress syndrome (ARDS), continues to represent a significant source of mortality in burned patients. Inhalation injury often requires mechanical ventilation, but the ideal tidal volume strategy is not clearly defined in burned pediatric patients. The aim of the present study is to determine the effects of low and high tidal volume on the number of ventilator days, ventilation pressures, and incidence of atelectasis, pneumonia and ARDS in pediatric burned patients with inhalation injury within one year post burn injury. Methods From 1986–2014, inhalation injury was diagnosed by bronchoscopy in pediatric burned patients (n=932). Patients were divided into three groups: (1) unventilated (n=241), (2) high tidal volume (HTV, 15 ± 3 ml/kg, n=190), and (3) low tidal volume (LTV, 9 ± 3 ml/kg, n = 501). Results HTV was associated with significantly decreased ventilator days (p<0.005) and maximum positive end expiratory pressure (p<0.0001) and significantly increased maximum peak inspiratory pressure (p<0.02) and plateau pressure (p<0.02) compared to patients with LTV. The incidence of atelectasis (p<0.0001) and ARDS (p<0.02) was significantly decreased with HTV compared to LTV. However, the incidence of pneumothorax was significantly increased in the HTV group compared with LTV (p<0.03). Conclusions HTV significantly decreases ventilator days and the incidence of both atelectasis and ARDS compared to low tidal volume in pediatric burned patients with inhalation injury. Thus, the use of HTV may interrupt sequences leading to lung injury in our patient population. PMID:25724604

  13. High tidal volume decreases adult respiratory distress syndrome, atelectasis, and ventilator days compared with low tidal volume in pediatric burned patients with inhalation injury.

    PubMed

    Sousse, Linda E; Herndon, David N; Andersen, Clark R; Ali, Arham; Benjamin, Nicole C; Granchi, Thomas; Suman, Oscar E; Mlcak, Ronald P

    2015-04-01

    Inhalation injury, which is among the causes of acute lung injury and acute respiratory distress syndrome (ARDS), continues to represent a significant source of mortality in burned patients. Inhalation injury often requires mechanical ventilation, but the ideal tidal volume strategy is not clearly defined in burned pediatric patients. The aim of this study was to determine the effects of low and high tidal volume on the number of ventilator days, ventilation pressures, and incidence of atelectasis, pneumonia, and ARDS in pediatric burned patients with inhalation injury within 1 year post burn injury. From 1986 to 2014, inhalation injury was diagnosed by bronchoscopy in pediatric burned patients (n = 932). Patients were divided into 3 groups: unventilated (n = 241), high tidal volume (HTV, 15 ± 3 mL/kg, n = 190), and low tidal volume (LTV, 9 ± 3 mL/kg, n = 501). High tidal volume was associated with significantly decreased ventilator days (p < 0.005) and maximum positive end expiratory pressure (p < 0.0001) and significantly increased maximum peak inspiratory pressure (p < 0.02) and plateau pressure (p < 0.02) compared with those in patients with LTV. The incidence of atelectasis (p < 0.0001) and ARDS (p < 0.02) was significantly decreased with HTV compared with LTV. However, the incidence of pneumothorax was significantly increased in the HTV group compared with the LTV group (p < 0.03). High tidal volume significantly decreases ventilator days and the incidence of both atelectasis and ARDS compared with low tidal volume in pediatric burned patients with inhalation injury. Therefore, the use of HTV may interrupt sequences leading to lung injury in our patient population. Copyright © 2015 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

  14. 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.

  15. Comparing the APACHE II score and IBM-10 score for predicting mortality in patients with ventilator-associated pneumonia.

    PubMed

    Naeini, Alireza Emami; Abbasi, Saeid; Haghighipour, Somayeh; Shirani, Kiana

    2015-01-01

    VAP is defined as pneumonia in patients who use ventilators. The acute physiology and chronic health evaluation (APACHE II) scoring system was originally developed for predicting mortality in patients who were admitted to the intensive care unit. Due to the complexity, a simpler score called IBMP-10 was developed. We designed the study to confirm and further investigate these two methods. This cross-sectional and analysis-descriptive study was done at the moment of VAP diagnosis on 60 patients in intensive care units. APACHE II and the IBMP-10 scores were calculated. ROC curves were generated to compare the new prediction rule with the APACHE II score. Results were reported as adjusted odds ratios with 95% confidence intervals (CIs). Analyses were performed using SPSS, version 20 and P values of 0.05 were considered to be statistically significant. APACHE II Score means (P < 0.001) and IBMP-10 score (P < 0.001) means had significant increase in Non-survivor patient than in patients who survived. APACHE II can be used as a good prediction measure for mortality rate. In IBMP-10 method, specificity and PPV were greater than APACHE II, but in mc-nemar test, there was no significant difference between the two methods (P = 0.55). Both prediction rules had high NPV. In our study, survivors' prediction value in APACHE II was 46.7%, and in IBMP-10, it was 46.7%. IBMP-10, compared to APACHE II, has greater sensitivity, specificity, and AUC to predict mortality. So the consequence of the use of IBMP-10 was better than APACHE II.

  16. Cost-effectiveness model of empiric doripenem compared with imipenem-cilastatin in ventilator-associated pneumonia.

    PubMed

    Zilberberg, Marya D; Mody, Samir H; Chen, Joyce; Shorr, Andrew F

    2010-10-01

    Ventilator-associated pneumonia (VAP) is a common complication of critical illness among surgical and trauma patients. Inappropriate empiric treatment of VAP increases the mortality rate. The rates of Pseudomonas aeruginosa (PA) VAP susceptibility to doripenem (DOR) are higher than those to imipenem-cilastatin (IMI). We developed a model to quantify outcome differences between strategies of empiric treatment of VAP with DOR vs. IMI. We designed a cost-effectiveness model comparing empiric treatment of VAP with DOR vs. IMI from both the hospital and societal perspectives. We examined the differences in the number of deaths, hospital length of stay (LOS), total costs, and quality-adjusted life years (QALY) under each scenario and conducted Monte Carlo simulations and sensitivity analyses to determine the stability of our estimates. Drug costs were taken as 80% of wholesale acquisition costs, with other inputs derived from the literature. In the base case analysis, assuming a PA-VAP attributable mortality rate of 38.4% and a 49% relative risk reduction in deaths in PA-sensitive (PA-S) infections to empiric drug compared with a resistant PA (PA-R) organism, DOR use resulted in three additional deaths avoided, 117.4 days of hospitalization averted, and hospital savings of $422,524 per 1,000 patients treated at a cost of $5,748/QALY. All estimates were most sensitive to the costs of treating PA-S and PA-R infections. In a multivariable analysis, hospital cost savings persisted across >80% of the simulations (95% confidence interval $432,615-$2,148,540). Given the current microbiologic sensitivity profile of PA to DOR and IMI, and depending on the local susceptibility patterns and in institutions where DOR in vitro susceptibilities are superior to those of other carbapenems for PA clinical isolates, empiric treatment of VAP with DOR may dominate that with IMI by being both life- and cost-saving.

  17. Comparative transduction mechanisms of hair cells in the bullfrog utriculus. II. Sensitivity and response dynamics to hair bundle displacement

    NASA Technical Reports Server (NTRS)

    Baird, R. A.

    1994-01-01

    1. Hair cells in whole-mount in vitro preparations of the utricular macula of the bullfrog (Rana catesbeiana) were selected according to their macular location and hair bundle morphology. The sensitivity and response dynamics of selected hair cells to natural stimulation were examined by recording their voltage responses to step and sinusoidal hair bundle displacements applied to their longest stereocilia. 2. The voltage responses of 31 hair cells to sinusoidal hair bundle displacements were characterized by their gains and phases, taken with respect to peak hair bundle displacement. The gains of Type B and Type C cells at both 0.5 and 5.0 Hz were markedly lower than those of Type F and Type E cells. Phases, with the exception of Type C cells, lagged hair bundle displacement at 0.5 Hz. Type C cells had phase leads of 25-40 degrees. At 5.0 Hz, response phases in all cells were phase lagged with respect to those at 0.5 Hz. Type C cells had larger gains and smaller phase leads at 5.0 Hz than at 0.5 Hz, suggesting the presence of low-frequency adaptation. 3. Displacement-response curves, derived from the voltage responses to 5.0-Hz sinusoids, were sigmoidal in shape and asymmetrical, with the depolarizing response having a greater magnitude and saturating less abruptly than the hyperpolarizing response. When normalized to their largest displacement the linear ranges of these curves varied from < 0.5 to 1.25 microns and were largest in Type B and smallest in Type F and Type E cells. Sensitivity, defined as the slope of the normalized displacement-response curve, was inversely correlated with linear range. 4. The contribution of geometric factors associated with the hair bundle to linear range and sensitivity were predicted from realistic models of utricular hair bundles created using morphological data obtained from light and electron microscopy. Three factors, including 1) the inverse ratio of the lengths of the kinocilium and longest stereocilia, representing the

  18. Comparative transduction mechanisms of hair cells in the bullfrog utriculus. II. Sensitivity and response dynamics to hair bundle displacement

    NASA Technical Reports Server (NTRS)

    Baird, R. A.

    1994-01-01

    1. Hair cells in whole-mount in vitro preparations of the utricular macula of the bullfrog (Rana catesbeiana) were selected according to their macular location and hair bundle morphology. The sensitivity and response dynamics of selected hair cells to natural stimulation were examined by recording their voltage responses to step and sinusoidal hair bundle displacements applied to their longest stereocilia. 2. The voltage responses of 31 hair cells to sinusoidal hair bundle displacements were characterized by their gains and phases, taken with respect to peak hair bundle displacement. The gains of Type B and Type C cells at both 0.5 and 5.0 Hz were markedly lower than those of Type F and Type E cells. Phases, with the exception of Type C cells, lagged hair bundle displacement at 0.5 Hz. Type C cells had phase leads of 25-40 degrees. At 5.0 Hz, response phases in all cells were phase lagged with respect to those at 0.5 Hz. Type C cells had larger gains and smaller phase leads at 5.0 Hz than at 0.5 Hz, suggesting the presence of low-frequency adaptation. 3. Displacement-response curves, derived from the voltage responses to 5.0-Hz sinusoids, were sigmoidal in shape and asymmetrical, with the depolarizing response having a greater magnitude and saturating less abruptly than the hyperpolarizing response. When normalized to their largest displacement the linear ranges of these curves varied from < 0.5 to 1.25 microns and were largest in Type B and smallest in Type F and Type E cells. Sensitivity, defined as the slope of the normalized displacement-response curve, was inversely correlated with linear range. 4. The contribution of geometric factors associated with the hair bundle to linear range and sensitivity were predicted from realistic models of utricular hair bundles created using morphological data obtained from light and electron microscopy. Three factors, including 1) the inverse ratio of the lengths of the kinocilium and longest stereocilia, representing the

  19. Precision displacement reference system

    DOEpatents

    Bieg, Lothar F.; Dubois, Robert R.; Strother, Jerry D.

    2000-02-22

    A precision displacement reference system is described, which enables real time accountability over the applied displacement feedback system to precision machine tools, positioning mechanisms, motion devices, and related operations. As independent measurements of tool location is taken by a displacement feedback system, a rotating reference disk compares feedback counts with performed motion. These measurements are compared to characterize and analyze real time mechanical and control performance during operation.

  20. Comparative assessment of change in fat mass using dual X-ray absorptiometry and air-displacement plethysmography.

    PubMed

    Warolin, Joshua; Kantor, Jeff; Whitaker, Lauren E; Choi, Leena; Acra, Sari; Buchowski, Maciej S

    2012-06-01

    To compare the accuracy of body composition measurements to small, defined changes in fat mass between dual X-ray absorptiometry (DXA) and air-displacement plethysmography (ADP). Fifty-six healthy adults, 29 women and 27 men (age, 38 ± 12.4 years; BMI, 27.6 ± 5.8 kg/m(2)) were included in the study. Exclusion criteria were pregnancy, indwelling metal hardware or pacemakers, or weight exceeding DXA table limit (>350 lbs). All individual testing was completed within a 2-hour period. Fat packets were prepared using lard wrapped in plastic and applied exogenously in defined locations. Each participant completed body composition measurements with ADP and DXA (both testing modalities completed with and without 1 kg of exogenously applied fat mass). Both DXA and ADP were highly accurate in detecting an overall increase in body mass associated with exogenously applied 1kg of fat mass (0.99 kg vs. 0.97 kg, respectively). DXA more accurately detected exogenous fat increase as fat mass compared to ADP (0.93 kg; 90% CI for the mean of the difference: 0.83 to 1.03 kg vs. 0.45 kg; 90% CI: 0.19 to 0.71 kg, respectively). The accuracy of body mass detection was similar for males and females (0.97 vs. 1.02 for DXA and 0.92 vs. 1.02 for ADP, respectively), though accuracy in detecting added mass as fat was less accurate in males than females (0.84 vs. 1.00 for DXA and 0.39 vs. 0.51 for ADP, respectively). Both DXA and ADP are accurate in detecting an overall increase in body mass associated with exogenously applied 1kg of fat mass. However, DXA is more accurate than ADP in correctly identifying the increase in body mass as fat mass, as opposed to fat free mass.

  1. Comparative assessment of change in fat mass using dual X-ray absorptiometry and air-displacement plethysmography

    PubMed Central

    Warolin, Joshua; Kantor, Jeff; Whitaker, Lauren E.; Choi, Leena; Acra, Sari; Buchowski, Maciej S.

    2012-01-01

    Objective To compare the accuracy of body composition measurements to small, defined changes in fat mass between dual X-ray absorptiometry (DXA) and air-displacement plethysmography (ADP). Methods Fifty-six healthy adults, 29 women and 27 men (age, 38 ± 12.4 years; BMI, 27.6 ± 5.8 kg/m2) were included in the study. Exclusion criteria were pregnancy, indwelling metal hardware or pacemakers, or weight exceeding DXA table limit (>350 lbs). All individual testing was completed within a 2-hour period. Fat packets were prepared using lard wrapped in plastic and applied exogenously in defined locations. Each participant completed body composition measurements with ADP and DXA (both testing modalities completed with and without 1 kg of exogenously applied fat mass). Results Both DXA and ADP were highly accurate in detecting an overall increase in body mass associated with exogenously applied 1kg of fat mass (0.99 kg vs. 0.97 kg, respectively). DXA more accurately detected exogenous fat increase as fat mass compared to ADP (0.93 kg; 90% CI for the mean of the difference: 0.83 to 1.03 kg vs. 0.45 kg; 90% CI: 0.19 to 0.71 kg, respectively). The accuracy of body mass detection was similar for males and females (0.97 vs. 1.02 for DXA and 0.92 vs. 1.02 for ADP, respectively), though accuracy in detecting added mass as fat was less accurate in males than females (0.84 vs. 1.00 for DXA and 0.39 vs. 0.51 for ADP, respectively) Discussion Both DXA and ADP are accurate in detecting an overall increase in body mass associated with exogenously applied 1kg of fat mass. However, DXA is more accurate than ADP in correctly identifying the increase in body mass as fat mass, as opposed to fat free mass. PMID:23162610

  2. Emergency capnography monitoring: comparing ergonomic design of intensive care unit ventilator interfaces and specific training of staff in reducing time to activation.

    PubMed

    Hodges, E; Griffiths, A; Richardson, J; Blunt, M; Young, P

    2012-08-01

    Modern ventilators provide capnography monitoring in patients with tracheal tubes, in compliance with national and international recommendations. This technology is often not used when patients' lungs are non-invasively ventilated; however, it should be accessed immediately following tracheal intubation to confirm tube placement. This study assessed the effect of ventilation interface design on the speed with which capnography can be activated by comparing the Dräger Evita 4 and Dräger V500 before and after a specific training episode. We configured the V500 to have a capnography activation button on the front screen in contrast to the Evita 4 which requires a sequence of actions to access capnography monitoring. We used a randomised crossover design, measuring time to monitoring activation, and repeated the study after 3 months. Survival analysis showed significantly quicker activation associated with ventilator choice (V500, p < 0.0001) and training (p = 0.0058). The training improved activation speed with both machines, though this was only significant for the Evita 4 (p = 0.0097). Anaesthesia © 2012 The Association of Anaesthetists of Great Britain and Ireland.

  3. Demand Controlled Ventilation and Classroom Ventilation

    SciTech Connect

    Fisk, William J.; Mendell, Mark J.; Davies, Molly; Eliseeva, Ekaterina; Faulkner, David; Hong, Tienzen; Sullivan, Douglas P.

    2012-05-01

    This document summarizes a research effort on demand controlled ventilation and classroom ventilation. The research on demand controlled ventilation included field studies and building energy modeling.

  4. Accuracy of Prediction Equations to Assess Percentage of Body Fat in Children and Adolescents with Down Syndrome Compared to Air Displacement Plethysmography

    ERIC Educational Resources Information Center

    Gonzalez-Aguero, A.; Vicente-Rodriguez, G.; Ara, I.; Moreno, L. A.; Casajus, J. A.

    2011-01-01

    To determine the accuracy of the published percentage body fat (%BF) prediction equations (Durnin et al., Johnston et al., Brook and Slaughter et al.) from skinfold thickness compared to air displacement plethysmography (ADP) in children and adolescents with Down syndrome (DS). Twenty-eight children and adolescents with DS (10-20 years old; 12…

  5. Accuracy of Prediction Equations to Assess Percentage of Body Fat in Children and Adolescents with Down Syndrome Compared to Air Displacement Plethysmography

    ERIC Educational Resources Information Center

    Gonzalez-Aguero, A.; Vicente-Rodriguez, G.; Ara, I.; Moreno, L. A.; Casajus, J. A.

    2011-01-01

    To determine the accuracy of the published percentage body fat (%BF) prediction equations (Durnin et al., Johnston et al., Brook and Slaughter et al.) from skinfold thickness compared to air displacement plethysmography (ADP) in children and adolescents with Down syndrome (DS). Twenty-eight children and adolescents with DS (10-20 years old; 12…

  6. Body-composition assessment in infancy: Air-displacement plethysmography compared with a reference 4-compartment model

    USDA-ARS?s Scientific Manuscript database

    Background: A better understanding of the associations of early infant nutrition and growth with adult health requires accurate assessment of body composition in infancy. Objective: This study evaluated the performance of an infant-sized air-displacement plethysmograph (PEA POD Infant Body Compositi...

  7. Retention of ventilation skills of emergency nurses after training with the SMART BAG compared to a standard bag-valve-mask.

    PubMed

    De Regge, Melissa; Vogels, Catherine; Monsieurs, Koenraad G; Calle, Paul A

    2006-03-01

    Studies show that nurses retain resuscitation skills poorly and that retention of ventilation skills is particularly difficult. We formed the hypothesis that the SMART BAG (SB, O-Two Medical Technologies Inc., Canada), i.e. a bag-valve-mask device with a pressure/flow responsive valve, would assist nurses in providing more efficient ventilation six months after training. Prior to training, 39 emergency nurses performed CPR for 2 min, in pairs, using a standard bag-valve-mask device (STBVM, Laerdal, Norway) to assess their base line skills. A CPR training manikin (Simulaids, USA) equipped with a PEEP valve in the oesophagus set at 20 cm H2O was used to measure inspiratory time, tidal volume (Vt), peak pressure and gastric insufflation (GI). Immediately following training they were tested using an O-Two STBVM and a SB. Half of the nurses were retested after three months, the other half after six months. Efficient ventilation was defined as a mean Vt>400 ml and GI<50 ml in 1 min. Before training, only 16% of nurses ventilated efficiently: 63% had GI and 28% had Vt<400 ml. Three months after training the efficiency of the STBVM and the SB was high (81 and 75%, respectively). Six months after training, there was a trend towards higher efficiency for the SB (63%) compared to the STBVM (25%) (p=0.07). For instances with the STBVM producing a Vt>400 ml, those without GI had a lower peak pressure than those with GI (7.8 cm H2O versus 17.7 cm H2O, p=0.0001) and showed a trend towards a longer inspiratory time (1.28 s versus 1.08 s, p=0.08). Of all efficient ventilations with a STBVM, 26% had a Vt>600 ml. Six months after training, nurses ventilated at least as efficiently with the SB, compared with the STBVM. This illustrates the ability of the SB to compensate for the deterioration over time in skill. On the other hand, training with a STBVM should focus primarily on prolonging the inspiratory time, and therefore the peak pressure, whilst maintaining an adequate Vt.

  8. Adaptive lung ventilation.

    PubMed

    Linton, D M

    2001-09-01

    Adaptive lung ventilation (ALV) is a method of closed-loop mechanical ventilation analogous to modern closed-loop technology in aviation such as the autopilot and automatic landing system. The algorithm of the controller of ALV is designed to automatically provide pressure-controlled synchronized intermittent mandatory ventilation (P-SIMV) and weaning as individually required in any clinical situation. The synchronized pressure limited breaths constantly adapt to the patient requirements to encourage optimal alveolar ventilation with minimal adverse physiological disturbance and timely weaning. The ease of application, efficiency, and safety of the first ALV controllers have been demonstrated in lung models, in patients with normal lungs undergoing general anesthesia, in patients requiring unusual positioning, in transition to and from one-lung anesthesia, and in long-term ventilation of patients with various lung pathologies and in weaning patients who have restrictive or obstructive pulmonary disease. Prospective comparative studies of ALV versus other currently used manually selected modes of mechanical ventilation, such as the one reported in this article, should confirm the safety and identify the benefits of this form of advanced closed-loop mechanical ventilation technology.

  9. On the horizon: liquid ventilation.

    PubMed

    Eanes, R

    1995-02-01

    Studies in preterm animals and humans have shown that liquid ventilation is a potential alternative mode of support for neonates with respiratory failure. Perfluorochemicals have a high solubility for respiratory gases and can be instilled in the lung using lower pressures than with gas ventilation. Other potential advantages of liquid ventilation include decreased alveolar surface tension, improved pulmonary mechanics, alveolar recruitment, and the removal of pulmonary debris. This article describes in detail what liquid ventilation is, compares the physiologic effects of liquid ventilation to gas ventilation, and presents the nursing implications of this technique. A review of the recent literature on the subject is presented, including reports of laboratory and clinical experience with liquid ventilation.

  10. Comparative study of displacement cascades simulated with 'magnetic' potentials and Mendelev-type potential in α-Fe

    NASA Astrophysics Data System (ADS)

    Gao, Chan; Tian, Dongfeng; Li, Maosheng; Qian, Dazhi

    2017-04-01

    Different interatomic potentials produce displacement cascades with different features, and hence they significantly influence the results obtained from the displacement cascade simulations. The displacement cascade simulations in α-Fe have been carried out by molecular dynamics with three 'magnetic' potentials (MP) and Mendelev-type potential in this paper. Prior to the cascade simulations, the 'magnetic' potentials are hardened to suit for cascade simulations. We find that the peak time, maximum of defects, cascade volume and cascade density with 'magnetic' potentials are smaller than those with Mendelev-type potential. There is no significant difference within statistical uncertainty in the defect production efficiency with Mendelev-type potential and the second 'magnetic' potential at the same cascade energy, but remarkably smaller than those with the first and third 'magnetic' potential. Self interstitial atom (SIA) clustered fractions with 'magnetic' potentials are smaller than that with Mendelev-type potential, especially at the higher energy, due to the larger interstitial formation energies which result from the 'magnetic' potentials. The defect clustered fractions, which are input data for radiation damage accumulation models, may influence the prediction of microstructural evolution under radiation.

  11. Comparing performance of three oscillating positive expiratory pressure devices at similar amplitude and frequencies of oscillations on displacement of mucus inside trachea during cough.

    PubMed

    Ragavan, Anpalaki J

    2012-03-13

    Performance of Flutter® (Axcan Scandipharm Inc, Birmingham, AL), Acapella® (Smiths Medicals Inc, Rockland, MA) and Quake® (Thayer Medical, Tucson, AZ) were compared at similar frequencies and amplitudes of oscillations at nine angles of the device in clearing simulated mucus inside a tracheal model (trachea) oriented at three angles with or without simulated constrictions in airway upstream of trachea. Displacement of 0.4mL of simulated mucus prepared with viscoelastic properties similar to healthy individuals (syrup-like) or patients with COPD (gel-like) using locust bean gum(LBG) solution (0.38g LBG in 100mL water) cross-linked with 3mL or 12mL borax solution (0.02 molar), respectively were measured inside trachea during coughs of 300ms at low cough velocity (15±0.5m/s) generated using a computer controlled solenoid valve. Oscillations were superimposed on cough by connecting the oscillator device to the outlet of the trachea. Frequency and amplitude of oscillations generated by Quake and Acapella and resulting mucus displacement were independent of angle of oscillator, while amplitude of oscillations and resulting mucus displacement generated by Flutter, increased up to 30o upward and 20o downward angles of Flutter from horizontal but decreased significantly thereafter. Displacement with Quake increased significantly with frequencies of oscillations up to 25 Hz and decreased thereafter but increased with amplitudes of oscillations up to 22±4.7 m/s. Quake showed significantly larger displacements than Flutter and Acapella at equal frequencies and amplitudes (p<0.05). Displacements were significantly larger with trachea positioned 30o upwards than horizontal or 20o downwards (p<0.0001). Displacement was the greatest for gel-like mucus than syrup-like (p<0.0001). Airway constrictions upstream resulted in enhanced displacement of mucus (p<0.0001). Mucus clearance can be significantly enhanced by coughing through oscillating positive expiratory devices that

  12. Mechanical Ventilation

    MedlinePlus

    ... cared for in a hospital’s intensive care unit (ICU). People who need a ventilator for a longer time may be in a regular unit of a hospital, a rehabilitation facility, or cared for at home. Why are ...

  13. Pulmonary mechanics during mechanical ventilation.

    PubMed

    Henderson, William R; Sheel, A William

    2012-03-15

    The use of mechanical ventilation has become widespread in the management of hypoxic respiratory failure. Investigations of pulmonary mechanics in this clinical scenario have demonstrated that there are significant differences in compliance, resistance and gas flow when compared with normal subjects. This paper will review the mechanisms by which pulmonary mechanics are assessed in mechanically ventilated patients and will review how the data can be used for investigative research purposes as well as to inform rational ventilator management.

  14. Accurate assessment of breast volume: a study comparing the volumetric gold standard (direct water displacement measurement of mastectomy specimen) with a 3D laser scanning technique.

    PubMed

    Yip, Jia Miin; Mouratova, Naila; Jeffery, Rebecca M; Veitch, Daisy E; Woodman, Richard J; Dean, Nicola R

    2012-02-01

    Preoperative assessment of breast volume could contribute significantly to the planning of breast-related procedures. The availability of 3D scanning technology provides us with an innovative method for doing this. We performed this study to compare measurements by this technology with breast volume measurement by water displacement. A total of 30 patients undergoing 39 mastectomies were recruited from our center. The volume of each patient's breast(s) was determined with a preoperative 3D laser scan. The volume of the mastectomy specimen was then measured in the operating theater by water displacement. There was a strong linear association between breast volumes measured using the 2 different methods when using a Pearson correlation (r = 0.95, P < 0.001). The mastectomy mean volume was defined by the equation: mastectomy mean volume = (scan mean volume × 1.03) -70.6. This close correlation validates the Cyberware WBX Scanner as a tool for assessment of breast volume.

  15. A Double-Blind Randomized Clinical Trial Comparing the Effect of Neostigmine and Metoclopramide on Gastric Residual Volume of Mechanically Ventilated ICU Patients

    PubMed Central

    Gholipour Baradari, Afshin; Alipour, Abbas; Firouzian, Abolfazl; Moarab, Laleh; Emami Zeydi, Amir

    2016-01-01

    Background: In critically ill patients, enteral feeding through the nasogastric tube is the method of choice for nutritional support. Gastrointestinal feeding intolerance and disturbed gastric emptying are common challenges in these patients. The aim of this study was to compare the effect of Neostigmine and Metoclopramide on gastric residual volume (GRV) in mechanically ventilated ICU patients. Methods: In a double blind, randomized clinical trial, a total of 60 mechanically ventilated ICU patients with GRV >120 mL (3 hours after the last gavage), were randomly assigned into two groups A and B. At baseline and 6 hours later, patients in group A and B received intravenous infusion of neostigmine in a dose of 2.5 mg and metoclopramide in a dose of 10 mg in 100 ml of normal saline, within 30 minutes. Patients’ gastric residual volumes were evaluated before the beginning of the intervention, and 3, 6, 9 and 12 hours after the intervention. Results: After adjusting of other variables (Sex, BMI and ICU stay period) generalized estimating equation (GEE) model revealed that neostigmine treatment increased odds of GRV improvement compare to metoclopramide group (Estimate 1.291, OR= 0.3.64, 95% CI 1.07-12.34). However there is a statistically significant time trend (within-subject differences or time effect) regardless of treatment groups (P<0.001). The median time from intervention to GRV improvement was 6 hours (95% CI 3.75-8.25) and 9 hours (95% CI 7.38-10.17) in neostigmine and metoclopramide groups, respectively. This difference was statistically significant (P<0.05). Conclusion: It seems that neostigmine is more effective than metoclopramide in reducing GRV and improving gastric emptying in mechanically ventilated ICU patients without significant complication and this protocol may be effective on the tolerance of enteral feeding in ICU patients. Further well-designed randomized clinical trials are needed. PMID:28077899

  16. Liquid ventilation

    PubMed Central

    Sarkar, Suman; Paswan, Anil; Prakas, S.

    2014-01-01

    Human have lungs to breathe air and they have no gills to breath liquids like fish. When the surface tension at the air-liquid interface of the lung increases as in acute lung injury, scientists started to think about filling the lung with fluid instead of air to reduce the surface tension and facilitate ventilation. Liquid ventilation (LV) is a technique of mechanical ventilation in which the lungs are insufflated with an oxygenated perfluorochemical liquid rather than an oxygen-containing gas mixture. The use of perfluorochemicals, rather than nitrogen as the inert carrier of oxygen and carbon dioxide offers a number of advantages for the treatment of acute lung injury. In addition, there are non-respiratory applications with expanding potential including pulmonary drug delivery and radiographic imaging. It is well-known that respiratory diseases are one of the most common causes of morbidity and mortality in intensive care unit. During the past few years several new modalities of treatment have been introduced. One of them and probably the most fascinating, is of LV. Partial LV, on which much of the existing research has concentrated, requires partial filling of lungs with perfluorocarbons (PFC's) and ventilation with gas tidal volumes using conventional mechanical ventilators. Various physico-chemical properties of PFC's make them the ideal media. It results in a dramatic improvement in lung compliance and oxygenation and decline in mean airway pressure and oxygen requirements. No long-term side-effect reported. PMID:25886321

  17. [Mechanical ventilator].

    PubMed

    Kimura, Akio; Hashimoto, S

    2009-07-01

    The development of the computer technology brought reform in the field of medical equipment. Originally the mechanical ventilator was an instrument only as for running by pressure and the tool that let you breathe. However, it has a function to assist a measurement (tidal volume, peek pressure, etc.) and to wean from a ventilator. There is a case to use a mechanical ventilator for after a chest surgical operation. After the operation without the complication, it seems that there is not the special administration. However, special respiratory management is necessary in case of chronic respiratory failure and acute lung injury, acute respiratory distress syndrome. Therefore I introduce a method to use a respirator after an operation in our institution.

  18. Nasal ventilation.

    PubMed Central

    Simonds, A. K.

    1998-01-01

    Nasal intermittent positive pressure ventilation is likely to have an increasing role in the management of acute ventilatory failure, weaning, and chronic ventilatory problems. Further improvements in ventilator and mask design will be seen. Appropriate application is likely to reduce both mortality and admissions to intensive care, while domiciliary use can improve life expectancy and/or quality of life in chronic ventilatory disorders. As with any new technique, enthusiasm should not outweigh clear outcome information, and possible new indications should always be subject to careful assessment. Images Figure 2 PMID:9799887

  19. Body-composition assessment in infancy: air-displacement plethysmography compared with a reference 4-compartment model.

    PubMed

    Ellis, Kenneth J; Yao, Manjiang; Shypailo, Roman J; Urlando, Alessandro; Wong, William W; Heird, William C

    2007-01-01

    A better understanding of the associations of early infant nutrition and growth with adult health requires accurate assessment of body composition in infancy. This study evaluated the performance of an infant-sized air-displacement plethysmograph (PEA POD Infant Body Composition System) for the measurement of body composition in infants. Healthy infants (n = 49; age: 1.7-23.0 wk; weight: 2.7-7.1 kg) were examined with the PEA POD system. Reference values for percentage body fat (%BF) were obtained from a 4-compartment (4-C) body-composition model, which was based on measurements of total body water, bone mineral content, and total body potassium. Mean (+/- SD) reproducibility of %BF values obtained with the PEA POD system was 0.4 +/- 1.3%. Mean %BF obtained with the PEA POD system (16.9 +/- 6.5%) did not differ significantly from that obtained with the 4-C model (16.3 +/- 7.2%), and the regression between %BF for the 4-C model and that for the PEA POD system (R2 = 0.73, SEE = 3.7%BF) did not deviate significantly from the line of identity (y = x). The PEA POD system provided a reliable, accurate, and immediate assessment of %BF in infants. Because of its ease of use, good precision, minimum safety concerns, and bedside accessibility, the PEA POD system is highly suitable for monitoring changes in body composition during infant growth in both the research and clinical settings.

  20. Early versus delayed reduction and pinning of type III displaced supracondylar fractures of the humerus in children: a comparative study.

    PubMed

    Iyengar, S R; Hoffinger, S A; Townsend, D R

    1999-01-01

    To determine whether children with Type III displaced supracondylar fractures of the humerus that were pinned in a delayed fashion, defined as more than eight hours after fracture, had a greater need for open reduction than patients with similar fractures pinned more urgently, within eight hours after the trauma. Also, to determine whether those patients treated later fared any worse than patients treated earlier. Retrospective review of consecutive patients. Level I pediatric trauma center at a tertiary children's hospital. Fifty-eight consecutive patients, twenty-three with early pinning and thirty-five with delayed pinning. A subgroup of sixteen patients was followed for detailed clinical outcome. Closed or open reduction and percutaneous pinning Need for open reduction in either group. A separate subgroup was examined for carrying angle and evidence of low-grade compartment syndrome (such as grip strength and range of motion). There was no difference in the need for open reduction in the group that was delayed and pinned more than eight hours following fracture. Follow-up examination showed no clinical difference between the two groups in any parameter measured. These results indicate that many supracondylar fractures of the humerus can be treated safely in a delayed manner with an excellent clinical result and without unduly prolonging the hospital stay (such as with traction). This allows the patient to be NPO and the surgeon to operate in daylight hours, saving time, hospital resources, and fatigue.

  1. The numerical stability of transformation-based CT ventilation.

    PubMed

    Castillo, Edward; Castillo, Richard; Vinogradskiy, Yevgeniy; Guerrero, Thomas

    2017-04-01

    Computed tomography (CT)-derived ventilation imaging utilizes deformable image registration (DIR) to recover respiratory-induced tissue volume changes from inhale/exhale 4DCT phases. While current strategies for validating CT ventilation rely on analyzing its correlation with existing functional imaging modalities, the numerical stability of the CT ventilation calculation has not been characterized. The purpose of this study is to examine how small changes in the DIR displacement field can affect the calculation of transformation-based CT ventilation. First, we derive a mathematical theorem, which states that the change in ventilation metric induced by a perturbation to single displacement vector is bounded by the perturbation magnitude. Second, we introduce a novel Jacobian constrained optimization method for computing user-defined CT ventilation images. Using the Jacobian constrained method, we demonstrate that for the same inhale/exhale CT pair, it is possible to compute two DIR transformations that have similar spatial accuracies, but generate ventilation images with significantly different physical characteristics. In particular, we compute a CT ventilation image that perfectly correlates with a single-photon emission CT perfusion scan. The analysis and experiments indicate that while transformation-based CT ventilation is a promising modality, small changes in the DIR displacement field can result in large relative changes in the ventilation image. As such, approaches for improving the reproducibility of CT ventilation are still needed.

  2. [Modalities of mechanical ventilation].

    PubMed

    Subirana, M; Bazan, P

    2000-01-01

    Mechanical ventilation improves the symptoms and reduces complications of acute respiratory failure. Recent advances in microprocessor technology have increased the sophistication of mechanical ventilators, thus leading to new ventilation modalities. This article describes the ventilation modalities available, grouping them as conventional, alternative and new modalities. Conventional ventilation includes the most widely used modalities, alternative ventilation includes less frequently used modalities, and new ventilation modalities include recently introduced options that are available on the latest-generation mechanical ventilators.

  3. A Randomized Trial Comparing Efficacy of Bubble and Ventilator Derived Nasal CPAP in Very Low Birth Weight Neonates with Respiratory Distress

    PubMed Central

    Agarwal, Sheetal; Roy, Mahesh K.; Verma, Ankit

    2016-01-01

    Introduction Continuous Positive Airway Pressure (CPAP) has an established role in the care of Very Low Birth Weight (VLBW) babies with respiratory distress. Bubble CPAP (BCPAP) is a cheap alternative for countries where resources are limited. However, data comparing efficacy of BCPAP with conventional ventilator derived (VCPAP) is limited. Aim To compare CPAP failure rates between BCPAP and VCPAP among VLBW, with moderate respiratory distress. Secondary objectives were to compare the rates of Intraventricular Haemorrhage (IVH), pulmonary air leaks and deaths between the two groups and determine the predictors of CPAP failure. Materials and Methods VLBW babies with moderate respiratory distress (Silverman Anderson score 4-7), born or admitted in Neonatal Intensive Care Unit (NICU) within 28 days of life were randomized to receive either BCPAP (n=34) or VCPAP (n=34). CPAP failure rate in both the groups was compared. Results The baseline characteristics were similar in both the groups. Five out of 34 (14.70%) babies in BCPAP group and 11 out of 34 (32.35%) in VCPAP failed CPAP (p=0.08). IVH (BCPAP group 24% and VCPAP group 9%, p= 0.10) and mortality (BCPAP group 6% and VCPAP group 9%, p=0.642) were comparable in both the groups. Factors such as gestational age <30 weeks, weight <1000 grams, Respiratory Distress Syndrome (RDS), shock, pulmonary haemorrhage, Disseminated Intravascular Coagulation (DIC) and multi-organ dysfunction were significantly associated with CPAP failure in our study. Conclusion The CPAP failure rates in VLBW babies with moderate respiratory distress were found to be similar whether bubble CPAP or ventilator CPAP was used. There was no difference in complication rates of IVH or mortality with either method of CPAP. PMID:27790540

  4. Ventilator waveforms.

    PubMed

    Mellema, Matthew S

    2013-08-01

    Ventilator waveforms are graphic representations of changes in pressure, flow, and volume within a ventilator circuit. The changes in these parameters over time may be displayed individually (scalars) or plotted one against another (pressure-volume and flow-volume loops). There are 6 basic shapes of scalar waveforms, but only 3 are functionally distinct (square, ramp, and sine). The pressure scalar is a particularly valuable tool when constant flow (e.g., volume control) modes are employed and an inspiratory pause is added. In this setting, inspection of the pressure waveform can allow determination of static, quasistatic, and dynamic compliance, as well as relative changes in airway resistance. Inspection of the pressure waveform can also help to identify many important aspects of patient drug responses, dyssynchrony, and air trapping (auto positive end-expiratory pressure [auto-PEEP]). Depending on the ventilation mode employed, the shape of the flow waveform may be set by the ventilator operator or may be dependent on patient effort and lung mechanics. Decelerating flow patterns have several important advantages when this option is available. Inspection of flow waveforms is crucial in the recognition of dyssynchrony, setting optimal inspiratory times, evaluating responses to bronchodilators, and the recognition of auto-PEEP. The volume waveform often contains somewhat less useful information than the other 2 scalars, but plays a crucial role in the identification of leaks in the circuit. Pressure-volume loops are particularly useful in setting PEEP and peak inspiratory pressure ranges. Inspection of these loops also often helps in the evaluation of lung mechanics, in the identification of circuit leaks, and in the assessment of patient triggering effort. Flow-volume loops are extremely useful in the identification of leaks and excessive airway secretions as well as alterations in airway resistance. Lastly, serial waveform inspection is crucial to the

  5. How do different brands of size 1 laryngeal mask airway compare with face mask ventilation in a dedicated laryngeal mask airway teaching manikin?

    PubMed

    Tracy, Mark Brian; Priyadarshi, Archana; Goel, Dimple; Lowe, Krista; Huvanandana, Jacqueline; Hinder, Murray

    2017-08-11

    International neonatal resuscitation guidelines recommend the use of laryngeal mask airway (LMA) with newborn infants (≥34 weeks' gestation or >2 kg weight) when bag-mask ventilation (BMV) or tracheal intubation is unsuccessful. Previous publications do not allow broad LMA device comparison. To compare delivered ventilation of seven brands of size 1 LMA devices with two brands of face mask using self-inflating bag (SIB). 40 experienced neonatal staff provided inflation cycles using SIB with positive end expiratory pressure (PEEP) (5 cmH2O) to a specialised newborn/infant training manikin randomised for each LMA and face mask. All subjects received prior education in LMA insertion and BMV. 12 415 recorded inflations for LMAs and face masks were analysed. Leak detected was lowest with i-gel brand, with a mean of 5.7% compared with face mask (triangular 42.7, round 35.7) and other LMAs (45.5-65.4) (p<0.001). Peak inspiratory pressure was higher with i-gel, with a mean of 28.9 cmH2O compared with face mask (triangular 22.8, round 25.8) and other LMAs (14.3-22.0) (p<0.001). PEEP was higher with i-gel, with a mean of 5.1 cmH2O compared with face mask (triangular 3.0, round 3.6) and other LMAs (0.6-2.6) (p<0.001). In contrast to other LMAs examined, i-gel had no insertion failures and all users found i-gel easy to use. This study has shown dramatic performance differences in delivered ventilation, mask leak and ease of use among seven different brands of LMA tested in a manikin model. This coupled with no partial or complete insertion failures and ease of use suggests i-gel LMA may have an expanded role with newborn resuscitation as a primary resuscitation device. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  6. Less wound complications of a sinus tarsi approach compared to an extended lateral approach for the treatment of displaced intraarticular calcaneal fracture

    PubMed Central

    Li, Lian-hua; Guo, Yong-zhi; Wang, Hao; Sang, Qing-hua; Zhang, Jian-zheng; Liu, Zhi; Sun, Tian-sheng

    2016-01-01

    Abstract Background: We conducted a prospective randomized clinical trial to compare the clinical and radiological outcomes of the sinus tarsi and extended lateral approaches for the surgical treatment of displaced intraarticular calcaneal fractures. Methods: Between January 2009 and January 2014, patients with displaced intraarticular calcaneal fracture were randomly assigned to receive surgical treatment by the sinus tarsi approach or the extended lateral approach using block randomization. We recorded and analyzed data on demographics, time to surgery, wound complications, Böhler angles pre- and postoperatively, and American Orthopedic Foot & Ankle Society score. Results: Sixty-four patients met the inclusion criteria and were randomly assigned to the 2 groups: 32 patients underwent sinus tarsi approach, and 32 patients the extended lateral approach. Baseline characteristics of both groups were similar. The time to surgery in the sinus tarsi approach group was significantly shorter than in the extended lateral approach group (P = 0.04). The wound complication rates were 6.3% and 31.2% in the sinus tarsi approach and extended lateral approach groups, respectively, which was significantly different (P = 0.01). Regarding the clinical outcomes, the groups did not differ significantly on walking visual analogue scale or American Orthopedic Foot & Ankle Society scores at 6 months and 1 year postoperatively. No significant differences existed between groups regarding the Böhler angle at different times and reduction quality of the articular surface and the medial wall. Conclusion: Compared with the extended lateral approach, the sinus tarsi approach decreased wound complications and preoperative waiting time, and achieved similar functional and radiological outcomes for displaced intraarticular calcaneal fractures. PMID:27603354

  7. Parental Perceptions of Quality of Life in Children on Long-Term Ventilation at Home as Compared to Enterostomy Tubes

    PubMed Central

    Redouane, Brahim; Cohen, Eyal; Stephens, Derek; Keilty, Krista; Mouzaki, Marialena; Narayanan, Unni; Moraes, Theo; Amin, Reshma

    2016-01-01

    Objective Health related quality of life (HRQL) of children using medical technology at home is largely unknown. Our aim was to examine the HRQL in children on long-term ventilation at home (LTHV) in comparison to a cohort using an enterostomy tube. Study Design Participants were divided into three groups: 1) LTHV without an enterostomy tube (LTHV cohort); 2) Enterostomy tube (GT cohort); 3) LTHV with an enterostomy tube (LTHV+GT cohort). Caregivers of children ≥ 5 years and followed at SickKids, Toronto, Canada, completed three questionnaires: Health Utilities Index 2/3 (HUI2/3), Caregiver Priorities Caregiver Health Index (CPCHILD), and the Paediatric Quality of Life Inventory (PedsQL). The primary outcome was the difference in utility (HUI2/3) scores between the cohorts. Results One hundred and nineteen children were enrolled; 47 in the LTHV cohort, 44 in the GT cohort, and 28 in the LTHV+GT cohort. In univariate analysis, HUI2 mean (SE) scores were lowest for the GT cohort, 0.4 (0.04) followed by the LTHV+GT, 0.42 (0.05) and then the LTHV cohort, 0.7 (0.04), p = 0.001. A similar trend was seen for the HUI3 mean (SE) scores: GT cohort, 0.1 (0.06), followed by the LTHV +GT cohort, 0.2 (0.08) and then the LTHV cohort, 0.5 (0.06), p = 0.0001. Technology cohort, nursing hours and the severity of health care needs predicted HRQL as measured by the HUI2/3. Conclusion The HRQL of these children is low. Children on LTHV had higher HRQL than children using enterostomy tubes. Further work is needed to identify modifiable factors that can improve HRQL. PMID:26914939

  8. Infusion of 2.5 meq/min of Lactic Acid minimally increases CO2 production compared to an isocaloric glucose infusion in healthy anesthetized, mechanically ventilated pigs.

    PubMed

    Zanella, Alberto; Giani, Marco; Redaelli, Sara; Mangili, Paolo; Scaravilli, Vittorio; Ormas, Valentina; Costanzi, Marco; Albertini, Mariangela; Bellani, Giacomo; Patroniti, Nicolò; Pesenti, Antonio

    2013-11-11

    Blood acidification by lactic acid infusion converts bicarbonate to CO2. This effect can be exploited to increase the transmembrane PCO2 gradient of an extracorporeal membrane lung, resulting in a significant increase of extracorporeal CO2 removal. Lactic acid, however, is an energetic substrate and its metabolism might increase total body CO2 production (VCO2), limiting the potential beneficial effects of this technique. The aim of our study was to compare VCO2 during isocaloric infusion of lactic acid or glucose. Six pigs (45 ± 5 kg) were sedated and mechanically ventilated. Estimated caloric needs were 2,300-2,400 Kcal/die (95 to 100 Kcal/h). A sequence of two steps lasting four hours each was performed: 1) Glucose, 97 kcal/h were administered as 50% glucose solution, and 2) Lactic Acid, approximately 48.5 kcal/h were administered as lactic acid and approximately 48.5 kcal/h as 50% glucose solution. This sequence was repeated three times with two-hour intervals. Every hour VCO2, arterial blood gases and lactate were measured. Blood glucose level was kept constant by titrating an insulin infusion, ventilation was adjusted to maintain arterial PCO2 at 50 mmHg, a normal value for our animal model. During Lactic Acid steps VCO2 increased less than 5% compared to the Glucose steps (282 vs. 269 ml/min, P < 0.05); blood glucose did not differ between the two groups (respectively 101 ± 12 vs. 103 ± 8 mg/dl). Arterial lactate was always lower than 3 mmol/L. Arterial pH was lower during Lactic Acid steps (7.422 vs. 7.445, P < 0.05). Replacing 50% of the caloric input with lactic acid increased total CO2 production by less than 5% compared to an equal caloric load provided entirely by a 50% glucose solution.

  9. Assisted mechanical ventilation: the future is now!

    PubMed

    Kacmarek, Robert M; Pirrone, Massimiliano; Berra, Lorenzo

    2015-07-29

    Assisted ventilation is a highly complex process that requires an intimate interaction between the ventilator and the patient. The complexity of this form of ventilation is frequently underappreciated by the bedside clinician. In assisted mechanical ventilation, regardless of the specific mode, the ventilator's gas delivery pattern and the patient's breathing pattern must match near perfectly or asynchrony between the patient and the ventilator occurs. Asynchrony can be categorized into four general types: flow asynchrony; trigger asynchrony; cycle asynchrony; and mode asynchrony. In an article recently published in BMC Anesthesiology, Hodane et al. have demonstrated reduced asynchrony during assisted ventilation with Neurally Adjusted Ventilatory Assist (NAVA) as compared to pressure support ventilation (PSV). These findings add to the growing volume of data indicating that modes of ventilation that provide proportional assistance to ventilation - e.g., NAVA and Proportional Assist Ventilation (PAV) - markedly reduce asynchrony. As it becomes more accepted that the respiratory center of the patient in most circumstances is the most appropriate determinant of ventilatory pattern and as the negative outcome effects of patient-ventilator asynchrony become ever more recognized, we can expect NAVA and PAV to become the preferred modes of assisted ventilation!

  10. Effects of intrapulmonary percussive ventilation on airway mucus clearance: A bench model

    PubMed Central

    Fernandez-Restrepo, Lorena; Shaffer, Lauren; Amalakuhan, Bravein; Restrepo, Marcos I; Peters, Jay; Restrepo, Ruben

    2017-01-01

    AIM To determine the ability of intrapulmonary percussive ventilation (IPV) to promote airway clearance in spontaneously breathing patients and those on mechanical ventilation. METHODS An artificial lung was used to simulate a spontaneously breathing patient (Group 1), and was then connected to a mechanical ventilator to simulate a patient on mechanical ventilation (Group 2). An 8.5 mm endotracheal tube (ETT) connected to the test lung, simulated the patient airway. Artificial mucus was instilled into the mid-portion of the ETT. A filter was attached at both ends of the ETT to collect the mucus displaced proximally (mouth-piece filter) and distally (lung filter). The IPV machine was attached to the proximal end of the ETT and was applied for 10-min each to Group 1 and 2. After each experiment, the weight of the various circuit components were determined and compared to their dry weights to calculate the weight of the displaced mucus. RESULTS In Group 1 (spontaneously breathing model), 26.8% ± 3.1% of the simulated mucus was displaced proximally, compared to 0% in Group 2 (the mechanically ventilated model) with a P-value of < 0.01. In fact, 17% ± 1.5% of the mucus in Group 2 remained in the mid-portion of the ETT where it was initially instilled and 80% ± 4.2% was displaced distally back towards the lung (P < 0.01). There was an overall statistically significant amount of mucus movement proximally towards the mouth-piece in the spontaneously breathing (SB) patient. There was also an overall statistically significant amount of mucus movement distally back towards the lung in the mechanically ventilated (MV) model. In the mechanically ventilated model, no mucus was observed to move towards the proximal/mouth piece section of the ETT. CONCLUSION This bench model suggests that IPV is associated with displacement of mucus towards the proximal mouthpiece in the SB patient, and distally in the MV model. PMID:28828301

  11. The comparative evaluation of treatment outcomes in pediatric displaced supracondylar humerus fractures managed with either open or closed reduction and percutaneous pinning.

    PubMed

    Keskin, D; Sen, H

    2014-01-01

    The aim of this study was to evaluate comparatively the outcomes of pediatric displaced supracondylar fractures of humerus which were treated with either closed reduction and percutaneous pinning (CRPP) or open reduction and percutaneous pinning (ORPP). The study included 100 children with displaced supracondylar fractures of the humerus, who were treated with either CRPP (group 1) or ORPP (group 2); the numbers of subjects in the study groups were equal. The treatment outcomes were assessed clinically and radiologically. Ninety-six percent excellent or good cosmetic results were achieved in both groups, and 94% / 90% excellent or good functional results were achieved in groups 1 and 2 (respectively). There was no signifiant difference between Baumann and humero-capitellar angles of intact and operated sides in both groups, but there was an average carrying angle difference of 2,96 degrees in the group 1 and 1,52 degrees in the group 2 and these differences were statistically signifiant. Five cases (10%) from each group had superfiial pin tract infection. Hypertrophic incision scar occurred in 6 (12%) patients performed ORPP. Both CRPP and ORPP are successful treatment methods in the management of non-complicated and non-comminuted displaced supracondylar fractures of the humerus in pediatric ages and their outcomes are similar. Incision scar and the long duration of operation are the disadvantages of open surgery. For fiing the fracture, placement of two K-wires from the medial and lateral aspects which cross each other is enough to achieve a good stability. In ORPP practices, lateral incision is a simple and reliable approach despite of the dissatisfying scar tissue formation.

  12. Comparing on-road real-time simultaneous in-cabin and outdoor particulate and gaseous concentrations for a range of ventilation scenarios

    NASA Astrophysics Data System (ADS)

    Leavey, Anna; Reed, Nathan; Patel, Sameer; Bradley, Kevin; Kulkarni, Pramod; Biswas, Pratim

    2017-10-01

    Advanced automobile technology, developed infrastructure, and changing economic markets have resulted in increasing commute times. Traffic is a major source of harmful pollutants and consequently daily peak exposures tend to occur near roadways or while travelling on them. The objective of this study was to measure simultaneous real-time particulate matter (particle numbers, lung-deposited surface area, PM2.5, particle number size distributions) and CO concentrations outside and in-cabin of an on-road car during regular commutes to and from work. Data was collected for different ventilation parameters (windows open or closed, fan on, AC on), whilst travelling along different road-types with varying traffic densities. Multiple predictor variables were examined using linear mixed-effects models. Ambient pollutants (NOx, PM2.5, CO) and meteorological variables (wind speed, temperature, relative humidity, dew point) explained 5-44% of outdoor pollutant variability, while the time spent travelling behind a bus was statistically significant for PM2.5, lung-deposited SA, and CO (adj-R2 values = 0.12, 0.10, 0.13). The geometric mean diameter (GMD) for outdoor aerosol was 34 nm. Larger cabin GMDs were observed when windows were closed compared to open (b = 4.3, p-value = <0.01). When windows were open, cabin total aerosol concentrations tracked those outdoors. With windows closed, the pollutants took longer to enter the vehicle cabin, but also longer to exit it. Concentrations of pollutants in cabin were influenced by outdoor concentrations, ambient temperature, and the window/ventilation parameters. As expected, particle number concentrations were impacted the most by changes to window position/ventilation, and PM2.5 the least. Car drivers can expect their highest exposures when driving with windows open or the fan on, and their lowest exposures during windows closed or the AC on. Final linear mixed-effects models could explain between 88 and 97% of cabin pollutant

  13. SU-D-BRB-01: 4D-CT Lung Ventilation Images Vary with 4D-CT Sorting Techniques.

    PubMed

    Yamamoto, T; Kabus, S; Lorenz, C; Johnston, E; Maxim, P; Loo, B; Keall, P

    2012-06-01

    4D-CT ventilation imaging is a novel promising technique for lung functional imaging and has potential as a biomarker for radiation pneumonitis, but has not been validated in human subjects. The current 4D- CT technique with phase-based sorting results in artifacts at an alarmingly high frequency (90%), which may introduce variations into ventilation calculations. The purpose of this study was to quantify the variability of 4D- CT ventilation imaging to 4D-CT sorting techniques. Two 4D-CT images were generated from the same data set by: (1) phase-based; (2) anatomic similarity- and abdominal displacement-based sorting for five patients. Two ventilation image sets (V_phase and V_anat) were then calculated by deformable image registration of peak-exhale and peak-inhale4D-CT images and quantification of regional volume change based on Hounsfield unit change. The variability of 4D-CT ventilation imaging wasquantified using the voxel-based Spearman rank correlation coefficients and Dice similarity coefficients (DSC) for the spatial overlap of segmented low- functional lung regions. The relationship between the abdominal motionrange variation and ventilation variation was also assessed using linearregression. Furthermore, the correlations between V_phase or V_anat and SPECT ventilation images (assumed ground-truth) were compared. In general, displacement- and anatomic similarity-based sorting reduced 4D- CT artifacts compared to phase-based sorting. The voxel-based correlationsbetween V_phase and V_anat were only moderate (range, 0.57-0.77). The DSCs for the low-functional lung regions were moderate to substantial (0.58-0.70). The relationship between the motion range variation and ventilation variation was strong on average (R2=0.79±0.25), suggesting that ventilation variations are related to 4D-CT artifacts. Vanat was found to improve correlations with SPECT ventilation images compared to V_phase. 4D-CT ventilation images vary markedly with 4D-CT sorting techniques. 4

  14. Comparative evaluation of the amount of gingival displacement produced by three different gingival retraction systems: An in vivo study

    PubMed Central

    Chaudhari, Jignesh; Prajapati, Paranjay; Patel, Jayanti; Sethuraman, Rajesh; Naveen, Y.G

    2015-01-01

    Statement of Problem: Tetrahydrozoline has been introduced as new gingival retraction agent but its clinical efficacy with widely used conventional retraction agents has not been tested. Purpose: The study was designed to clinically evaluate efficacy of newer retraction agent tetrahydrozoline with two widely used retraction systems i.e., Expasyl retraction system and medicated retraction cords on basis of amount of gingival retraction. Materials and Methods: 30 subjects were selected according to inclusion and exclusion criteria. Maxillary Impressions were made with irreversible hydrocolloid for all subjects. Tray material was used for making the special tray. Latin Block Design was Used in the Study to avoid tissue fatigue. Retraction was done with aluminium chloride; Tetrahydrozoline and Expasyl according to Latin block design. Impressions were poured with die stone. Casts were retrieved and sections were made with die cutter. 3 mm thin slices were obtained. Each slice was used to measure the amount of retraction under stereomicroscope under 20x and images were transferred to image analyser. Results: The amount of gingival retraction obtained by using aluminium chloride as gingival retraction agent was maximum (148238.33 μm2) compared to tetrahydrozoline (140737.87 μm2) and Expasyl (67784.90 μm2). PMID:26097353

  15. Does Kapandji wiring help in older patients? A retrospective comparative review of displaced intra-articular distal radial fractures in patients over 55 years.

    PubMed

    Board, T; Kocialkowski, A; Andrew, G

    1999-12-01

    Forty-six patients aged 55-90 with intra-articular displaced fractures of the distal radius were reviewed retrospectively. All patients were treated with either manipulation and plaster of Paris or Kapandji wiring. Radiographic and functional review was performed by an independent observer a mean of 17 months after the fracture. The results showed superior anatomical and functional results in the group treated with Kapandji wiring. The mean dorsal angle was significantly better in the wired group, and the improvement in dorsal angle, radial angle and radial length from presentation to final result was also significantly better. Functional results were excellent or good in 19/23 of the wired group, compared with 12/23 of the plaster group. There was a strong correlation between functional outcome and both dorsal angle and radial length at union. These results support the use of this method of wire fixation in older patients, as the technique is simple and complications were few.

  16. Space station ventilation study

    NASA Technical Reports Server (NTRS)

    Colombo, G. V.; Allen, G. E.

    1972-01-01

    A ventilation system design and selection method which is applicable to any manned vehicle were developed. The method was used to generate design options for the NASA 33-foot diameter space station, all of which meet the ventilation system design requirements. System characteristics such as weight, volume, and power were normalized to dollar costs for each option. Total system costs for the various options ranged from a worst case $8 million to a group of four which were all approximately $2 million. A system design was then chosen from the $2 million group and is presented in detail. A ventilation system layout was designed for the MSFC space station mockup which provided comfortable, efficient ventilation of the mockup. A conditioned air distribution system design for the 14-foot diameter modular space station, using the same techniques, is also presented. The tradeoff study resulted in the selection of a system which costs $1.9 million, as compared to the alternate configuration which would have cost $2.6 million.

  17. An engine with means for changing the phase angle between displacer and working pistons - Its thermo dynamic cycle compared to the ideal Stirling cycle

    NASA Astrophysics Data System (ADS)

    Ayala v., E.

    This paper describes a heat engine comprising a displacer piston actuated by the pressure changes accomplished by the working piston combined with the force exerted by the pressure of a spring against the piston which can be changed to modify the phase angle between the displacer and working pistons. A gas cooler is arranged in an independent closed loop circuit that is put into operation between the end of the expansion stroke and the beginning of the compression stroke. The working cylinder is connected to the cold end of the displacer cylinder through an auxiliary cooler and to the end of the displacer cylinder through the heat regenerator and the heater.

  18. Coronary CTA using scout-based automated tube potential and current selection algorithm, with breast displacement results in lower radiation exposure in females compared to males

    PubMed Central

    Vadvala, Harshna; Kim, Phillip; Mayrhofer, Thomas; Pianykh, Oleg; Kalra, Mannudeep; Hoffmann, Udo

    2014-01-01

    Purpose To evaluate the effect of automatic tube potential selection and automatic exposure control combined with female breast displacement during coronary computed tomography angiography (CCTA) on radiation exposure in women versus men of the same body size. Materials and methods Consecutive clinical exams between January 2012 and July 2013 at an academic medical center were retrospectively analyzed. All examinations were performed using ECG-gating, automated tube potential, and tube current selection algorithm (APS-AEC) with breast displacement in females. Cohorts were stratified by sex and standard World Health Organization body mass index (BMI) ranges. CT dose index volume (CTDIvol), dose length product (DLP) median effective dose (ED), and size specific dose estimate (SSDE) were recorded. Univariable and multivariable regression analyses were performed to evaluate the effect of gender on radiation exposure per BMI. Results A total of 726 exams were included, 343 (47%) were females; mean BMI was similar by gender (28.6±6.9 kg/m2 females vs. 29.2±6.3 kg/m2 males; P=0.168). Median ED was 2.3 mSv (1.4-5.2) for females and 3.6 (2.5-5.9) for males (P<0.001). Females were exposed to less radiation by a difference in median ED of –1.3 mSv, CTDIvol –4.1 mGy, and SSDE –6.8 mGy (all P<0.001). After adjusting for BMI, patient characteristics, and gating mode, females exposure was lower by a median ED of –0.7 mSv, CTDIvol –2.3 mGy, and SSDE –3.15 mGy, respectively (all P<0.01). Conclusions: We observed a difference in radiation exposure to patients undergoing CCTA with the combined use of AEC-APS and breast displacement in female patients as compared to their BMI-matched male counterparts, with female patients receiving one third less exposure. PMID:25610804

  19. Ventilation efficiencies of a desk-edge-mounted task ventilation system

    SciTech Connect

    Faulkner, David; Fisk, William J.; Sullivan, Douglas P.; Lee, Seung Min

    2002-03-01

    In chamber experiments, we investigated the effectiveness of a task ventilation system with an air supply nozzle located underneath the front edge of a desk and directing air toward a heated mannequin seated at the desk. The task ventilation system provided outside air, while another ventilation system provided additional space cooling but no outside air. Test variables included the vertical angle of air supply (-15{sup o} to 45{sup o} from horizontal), and the supply flow rate of (3.5 to 6.5 L s{sup -1}). Using the tracer gas step-up and step-down procedures, the measured air change effectiveness (i.e., exhaust air age divided by age of air at the mannequin's face) ranged from 1.4 to 2.7, which is higher than typically reported for commercially available task ventilation or displacement ventilation systems.

  20. Transient natural ventilation of a room with a distributed heat source

    NASA Astrophysics Data System (ADS)

    Fitzgerald, Shaun D.; Woods, Andrew W.

    We report on an experimental and theoretical study of the transient flows which develop as a naturally ventilated room adjusts from one temperature to another. We focus on a room heated from below by a uniform heat source, with both high- and low-level ventilation openings. Depending on the initial temperature of the room relative to (i) the final equilibrium temperature and (ii) the exterior temperature, three different modes of ventilation may develop. First, if the room temperature lies between the exterior and the equilibrium temperature, the interior remains well-mixed and gradually heats up to the equilibrium temperature. Secondly, if the room is initially warmer than the equilibrium temperature, then a thermal stratification develops in which the upper layer of originally hot air is displaced upwards by a lower layer of relatively cool inflowing air. At the interface, some mixing occurs owing to the effects of penetrative convection. Thirdly, if the room is initially cooler than the exterior, then on opening the vents, the original air is displaced downwards and a layer of ambient air deepens from above. As this lower layer drains, it is eventually heated to the ambient temperature, and is then able to mix into the overlying layer of external air, and the room becomes well-mixed. For each case, we present new laboratory experiments and compare these with some new quantitative models of the transient flows. We conclude by considering the implications of our work for natural ventilation of large auditoria.

  1. Displacement parameter inversion for a novel electromagnetic underground displacement sensor.

    PubMed

    Shentu, Nanying; Li, Qing; Li, Xiong; Tong, Renyuan; Shentu, Nankai; Jiang, Guoqing; Qiu, Guohua

    2014-05-22

    Underground displacement monitoring is an effective method to explore deep into rock and soil masses for execution of subsurface displacement measurements. It is not only an important means of geological hazards prediction and forecasting, but also a forefront, hot and sophisticated subject in current geological disaster monitoring. In previous research, the authors had designed a novel electromagnetic underground horizontal displacement sensor (called the H-type sensor) by combining basic electromagnetic induction principles with modern sensing techniques and established a mutual voltage measurement theoretical model called the Equation-based Equivalent Loop Approach (EELA). Based on that work, this paper presents an underground displacement inversion approach named "EELA forward modeling-approximate inversion method". Combining the EELA forward simulation approach with the approximate optimization inversion theory, it can deduce the underground horizontal displacement through parameter inversion of the H-type sensor. Comprehensive and comparative studies have been conducted between the experimentally measured and theoretically inversed values of horizontal displacement under counterpart conditions. The results show when the measured horizontal displacements are in the 0-100 mm range, the horizontal displacement inversion discrepancy is generally tested to be less than 3 mm under varied tilt angles and initial axial distances conditions, which indicates that our proposed parameter inversion method can predict underground horizontal displacement measurements effectively and robustly for the H-type sensor and the technique is applicable for practical geo-engineering applications.

  2. Displacement Parameter Inversion for a Novel Electromagnetic Underground Displacement Sensor

    PubMed Central

    Shentu, Nanying; Li, Qing; Li, Xiong; Tong, Renyuan; Shentu, Nankai; Jiang, Guoqing; Qiu, Guohua

    2014-01-01

    Underground displacement monitoring is an effective method to explore deep into rock and soil masses for execution of subsurface displacement measurements. It is not only an important means of geological hazards prediction and forecasting, but also a forefront, hot and sophisticated subject in current geological disaster monitoring. In previous research, the authors had designed a novel electromagnetic underground horizontal displacement sensor (called the H-type sensor) by combining basic electromagnetic induction principles with modern sensing techniques and established a mutual voltage measurement theoretical model called the Equation-based Equivalent Loop Approach (EELA). Based on that work, this paper presents an underground displacement inversion approach named “EELA forward modeling-approximate inversion method”. Combining the EELA forward simulation approach with the approximate optimization inversion theory, it can deduce the underground horizontal displacement through parameter inversion of the H-type sensor. Comprehensive and comparative studies have been conducted between the experimentally measured and theoretically inversed values of horizontal displacement under counterpart conditions. The results show when the measured horizontal displacements are in the 0–100 mm range, the horizontal displacement inversion discrepancy is generally tested to be less than 3 mm under varied tilt angles and initial axial distances conditions, which indicates that our proposed parameter inversion method can predict underground horizontal displacement measurements effectively and robustly for the H-type sensor and the technique is applicable for practical geo-engineering applications. PMID:24858960

  3. Measuring vulnerability to disaster displacement

    NASA Astrophysics Data System (ADS)

    Brink, Susan A.; Khazai, Bijan; Power, Christopher; Wenzel, Friedemann

    2015-04-01

    aggregate these ideas into a framework of disaster displacement vulnerability that distinguishes between three main aspects of disaster displacement. Disaster displacement can be considered in terms of the number of displaced people and the length of that displacement. However, the literature emphasizes that the severity of disaster displacement can not be measured completely in quantitative terms. Thus, we include a measure representing people who are trapped and unable to leave their homes due to mobility, resources or for other reasons. Finally the third main aspect considers the difficulties that are associated with displacement and reflects the difference between the experiences of those who are displaced into safe and supportive environments as compared to those whose only alternate shelter is dangerous and inadequate for their needs. Finally, we apply the framework to demonstrate a methodology to estimate vulnerability to disaster displacement. Using data from the Global Earthquake Model (GEM) Social and Economic Vulnerability sub-National Database, we generate an index to measure the vulnerability of Japanese prefectures to the dimensions of displacement included in the framework. References Yonitani, M. (2014). Global Estimates 2014: People displaced by disasters. http://www.internal-displacement.org/publications/2014/global-estimates-2014-people-displaced-by-disasters/

  4. VENTILATION NEEDS DURING CONSTRUCTION

    SciTech Connect

    C.R. Gorrell

    1998-07-23

    The purpose of this analysis is to determine ventilation needs during construction and development of the subsurface repository and develop systems to satisfy those needs. For this analysis, construction is defined as pre-emplacement excavation and development is excavation that takes place simultaneously with emplacement. The three options presented in the ''Overall Development and Emplacement Ventilation Systems'' analysis (Reference 5.5) for development ventilation will be applied to construction ventilation in this analysis as well as adding new and updated ventilation factors to each option for both construction and development. The objective of this analysis is to develop a preferred ventilation system to support License Application Design. The scope of this analysis includes: (1) Description of ventilation conditions; (2) Ventilation factors (fire hazards, dust control, construction logistics, and monitoring and control systems); (3) Local ventilation alternatives; (4) Global ventilation options; and (5) Evaluation of options.

  5. 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

  6. Variable mechanical ventilation.

    PubMed

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

    2017-01-01

    To review the literature on the use of variable mechanical ventilation and the main outcomes of this technique. 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". A total of 36 studies were selected. Of these, 24 were original studies, including 21 experimental studies and three clinical studies. 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.

  7. Accuracy of prediction equations to assess percentage of body fat in children and adolescents with Down syndrome compared to air displacement plethysmography.

    PubMed

    González-Agüero, A; Vicente-Rodríguez, G; Ara, I; Moreno, L A; Casajús, J A

    2011-01-01

    To determine the accuracy of the published percentage body fat (%BF) prediction equations (Durnin et al., Johnston et al., Brook and Slaughter et al.) from skinfold thickness compared to air displacement plethysmography (ADP) in children and adolescents with Down syndrome (DS). Twenty-eight children and adolescents with DS (10-20 years old; 12 girls, 16 boys) participated in the study. Anthropometric measurements height, weight, and skinfolds biceps, triceps, subscapular and suprailiac were performed following ISAK recommendations. Total body density (TBD) was estimated using three equations and was also measured with ADP; while %BF was calculated from all densities using the Siri equation and from skinfolds using the Slaughter et al. equation. Finally, the agreement between methods was assessed by plotting the results in Bland-Altman graphs. The presence of heteroscedasticity was also examined. Despite the equation of Slaughter et al. had a large 95% limits of agreement, it was the only one without a significant inter-methods difference and without heteroscedasticity. The equation of Slaughter seems to be, from the studied, the most accurate for estimating %BF in children and adolescents with DS. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Diagnostic value of the strand displacement amplification method compared to those of Roche Amplicor PCR and culture for detecting mycobacteria in sputum samples.

    PubMed Central

    Ichiyama, S; Ito, Y; Sugiura, F; Iinuma, Y; Yamori, S; Shimojima, M; Hasegawa, Y; Shimokata, K; Nakashima, N

    1997-01-01

    We compared the ability of the semiautomated BDProbeTec-SDA system, which uses the strand displacement amplification (SDA) method, with that of the Roche Amplicor-PCR system and the Septi-Chek AFB culture system to directly detect Mycobacterium tuberculosis complex (MTB) and other mycobacteria in sputum samples. A total of 530 sputum samples from 299 patients were examined in this study. Of the 530 samples, 129 were culture positive for acid-fast bacilli with the Septi-Chek AFB system; 95 for MTB, 29 for M. avium-M. intracellulare complex (MAC), and 5 for other mycobacteria. The BDProbeTec-SDA system detected 90 of the 95 samples culture positive for MTB (sensitivity, 94.7%), and the Amplicor-PCR system detected 85 of the 95 samples culture positive for MTB (sensitivity, 89.5%). The specificity of each system, based on the clinical diagnosis, was 99.8% for SDA and 100% for PCR, respectively. Among the 29 samples culture positive for MAC, the BDProbeTec-SDA system detected MAC in 24 samples (sensitivity, 82.8%), whereas the Amplicor-PCR system detected MAC in 23 samples (sensitivity, 79.3%). The specificities of the systems were 98.3 and 100%, respectively. The high degrees of sensitivity and specificity of the BDProbeTec-SDA system suggest that it should be very useful in clinical laboratories for the rapid detection of mycobacteria in sputum samples. PMID:9399498

  9. Five-year follow-up results of the PROFHER trial comparing operative and non-operative treatment of adults with a displaced fracture of the proximal humerus

    PubMed Central

    Handoll, H. H.; Keding, A.; Corbacho, B.; Brealey, S. D.; Hewitt, C.; Rangan, A.

    2017-01-01

    Aims The PROximal Fracture of the Humerus Evaluation by Randomisation (PROFHER) randomised clinical trial compared the operative and non-operative treatment of adults with a displaced fracture of the proximal humerus involving the surgical neck. The aim of this study was to determine the long-term treatment effects beyond the two-year follow-up. Patients and Methods Of the original 250 trial participants, 176 consented to extended follow-up and were sent postal questionnaires at three, four and five years after recruitment to the trial. The Oxford Shoulder Score (OSS; the primary outcome), EuroQol 5D-3L (EQ-5D-3L), and any recent shoulder operations and fracture data were collected. Statistical and economic analyses, consistent with those of the main trial were applied. Results OSS data were available for 164, 155 and 149 participants at three, four and five years, respectively. There were no statistically or clinically significant differences between operative and non-operative treatment at each follow-up point. No participant had secondary shoulder surgery for a new complication. Analyses of EQ-5D-3L data showed no significant between-group differences in quality of life over time. Conclusion These results confirm that the main findings of the PROFHER trial over two years are unchanged at five years. Cite this article: Bone Joint J 2017;99-B:383–92. PMID:28249980

  10. Comparing the efficacy of nebulizer recombinant human DNase and hypertonic saline as monotherapy and combined treatment in the treatment of persistent atelectasis in mechanically ventilated newborns.

    PubMed

    Altunhan, Hüseyin; Annagür, Ali; Pekcan, Sevgi; Ors, Rahmi; Koç, Hasan

    2012-02-01

    The purpose of the present study was to compare the cost-effectiveness and efficacy of nebulizer recombinant human DNase (rhDNase) and hypertonic saline (HS) as monotherapy and combined treatment in neonatal atelectasis. Eighty-seven newborns with persistent atelectasis who did not respond to traditional treatment were studied retrospectively. Group 1 did not receive nebulizer drugs; Group 2 received 7%HS; Group 3 received rhDNase; and Group 4 received both 7%HS and rhDNase. Subjects' chest X-ray scores, partial pressure of CO(2), respiratory rate, fraction of inspired oxygen (FiO(2)) peak inspiratory pressure, atelectasis healing rate, median duration of nebulizer treatment and costs were compared. Percentages of improvement in atelectasis on Day 3 of treatment in Group 1, Group 2, Group 3 and Group 4 were 27, 70, 81 and 95%, respectively, while median duration of treatment was 8.1, 3.3, 2.9 and 2.4 days, respectively. Comparison of chest X-ray scores, partial pressure of CO(2), respiratory rate, FiO(2) and peak inspiratory pressure values before and 48 h after treatment did not yield a significant difference for the control group (P > 0.05), while a marked improvement was observed in other groups for all parameters (P < 0.05). The most distinct improvement was in Group 4, followed by Group 3. Although both the combined treatment with HS and rhDNase and their monotherapies are effective in the treatment of persistent atelectasis in newborns receiving mechanical ventilation, their combined use produces higher efficacy. The efficacy of rhDNase is superior to monotherapy with HS. Use of these two treatments concomitantly reduces the cost. To the best of our knowledge, the present study is the first to use HS alone or in combination with rhDNase in newborn patients. © 2011 The Authors. Pediatrics International © 2011 Japan Pediatric Society.

  11. 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

  12. Lateral displacement and rotational displacement sensor

    DOEpatents

    Duden, Thomas

    2014-04-22

    A position measuring sensor formed from opposing sets of capacitor plates measures both rotational displacement and lateral displacement from the changes in capacitances as overlapping areas of capacitors change. Capacitances are measured by a measuring circuit. The measured capacitances are provided to a calculating circuit that performs calculations to obtain angular and lateral displacement from the capacitances measured by the measuring circuit.

  13. Control of airborne infectious diseases in ventilated spaces.

    PubMed

    Nielsen, Peter V

    2009-12-06

    We protect ourselves from airborne cross-infection in the indoor environment by supplying fresh air to a room by natural or mechanical ventilation. The air is distributed in the room according to different principles: mixing ventilation, displacement ventilation, etc. A large amount of air is supplied to the room to ensure a dilution of airborne infection. Analyses of the flow in the room show that there are a number of parameters that play an important role in minimizing airborne cross-infection. The air flow rate to the room must be high, and the air distribution pattern can be designed to have high ventilation effectiveness. Furthermore, personalized ventilation may reduce the risk of cross-infection, and in some cases, it can also reduce the source of infection. Personalized ventilation can especially be used in hospital wards, aircraft cabins and, in general, where people are in fixed positions.

  14. Ventilation of Nonparalyzed Patients Under Anesthesia with Laryngeal Mask Airway, Comparison of Three Modes of Ventilation: Volume Controlled Ventilation, Pressure Controlled Ventilation, and Pressure Controlled Ventilation-volume Guarantee.

    PubMed

    Ghabach, Maroun Badwi; El Hajj, Elie M; El Dib, Rouba D; Rkaiby, Jeanette M; Matta, May S; Helou, May R

    2017-01-01

    Pressure controlled ventilation (PCV) is the preferable mode of ventilation of nonparalyzed patients undergoing anesthesia with laryngeal mask airway (LMA) as compared to volume controlled ventilation (VCV) and spontaneously breathing patient. In this study, we compared the PC-volume guarantee (PC-VG) mode of ventilation with VCV and PCV modes. A total of 30 patients, American Society of Anesthesiologists (ASA) physical status Classes I and II, scheduled for elective surgery under general anesthesia with a classic LMA were ventilated, subsequently, with the three modes of ventilation: VCV, PCV, and PC-VG for 10 min each mode. Tidal volume set for all patients was 8 ml/kg of ideal body weight. Parameters measured with modes of ventilation include peak inspiratory pressure (PIP), compliance, measured tidal volume, O2 saturation, end-tidal CO2, and presence of an oropharyngeal leak. The PIP was significantly higher with the application of VCV mode of ventilation than PCV and PC-VG modes. The compliance was significantly lower when using the mode of ventilation VCV than PCV and PC-VG. The PIP and the compliance were not statistically different between the PCV and PC-VG modes of ventilation. Ventilation of nonparalyzed patients with LMA under anesthesia with PC-VG is advantageous over VCV in reducing PIP and increasing lung compliance. No difference was noted between PCV and PC-VG in ASA Classes I or II under the adequate depth of anesthesia in patients with normal pulmonary function.

  15. Endotoxemia accelerates diaphragm dysfunction in ventilated rabbits.

    PubMed

    Yang, Yi; Yu, Tao; Pan, Chun; Longhini, Federico; Liu, Ling; Huang, Yingzi; Guo, Fengmei; Qiu, Haibo

    2016-12-01

    Ventilators may induce diaphragm dysfunction, and most of the septic population who are admitted to the intensive care unit require mechanical ventilation. However, there is no evidence that sepsis accelerates the onset of ventilator-induced diaphragm dysfunction or affects the microcirculation. Our study investigated whether lipopolysaccharide (LPS)-induced endotoxemia accelerated diaphragm dysfunction in ventilated rabbits by evaluating microcirculation, lipid accumulation, and diaphragm contractility. After anesthesia and tracheostomy, 25 invasively monitored and mechanically ventilated New Zealand white rabbits were randomized to control (n = 5), controlled mechanical ventilation (CMV) (n = 5), pressure support ventilation (PSV; n = 5), CMV or PSV with LPS-induced endotoxemia (CMV-LPS and PSV-LPS, respectively; n = 5 for each). Rabbits were anesthetized and ventilated for 24 h, except the control rabbits (30 min). Diaphragmatic contractility was evaluated using neuromechanical and neuroventilatory efficiency. We evaluated the following at the end of the protocol: (1) diaphragm microcirculation; (2) lipid accumulation; and (3) diaphragm muscular fibers structure. Diaphragm contractility, microcirculation, lipid accumulation, and fiber structures were severely compromised in endotoxemic animals after 24 h compared to nonendotoxemic rabbits. Moreover, a slight but significant increase in lipid accumulation was observed in CMV and PSV groups compared with controls (P < 0.05). Endotoxemia accelerates the diaphragm dysfunction process in ventilated rabbits, affects the microcirculation, and results in diaphragmatic lipid accumulation and contractility impairment. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Home Ventilator Guide

    MedlinePlus

    ... are for negative pressure ventilators currently on the markets. There is no “standard” form for specifications. American ... specifications are for bilevel ventilators currently on the markets. There is no “standard” form for specifications. American ...

  17. Anesthesia and critical care ventilator modes: past, present, and future.

    PubMed

    Bristle, Timothy J; Collins, Shawn; Hewer, Ian; Hollifield, Kevin

    2014-10-01

    Mechanical ventilators have evolved from basic machines to complicated, electronic, microprocessing engines. Over the last 2 decades, ventilator capabilities and options for critical care and anesthesia ventilators have rapidly advanced. These advances in ventilator modalities--in conjunction with a better understanding of patient physiology and the effects of positive pressure ventilation on the body--have revolutionized the mechanical ventilation process. Clinicians today have a vast array of mechanical ventilator mode options designed to match the pulmonary needs of the critically ill and anesthetized patient. Modes of mechanical ventilation continue to be based on 1 of 2 variances: volume-based or pressure-based. The wording describing the standard ventilatory modes on select present-day ventilators has changed, yet the basic principles of operation have not changed compared with older ventilators. Anesthesia providers need to understand these ventilator modes to best care for patients. This literature review encompasses a brief history of mechanical ventilation and current modes available for anesthesia and critical care ventilators, including definitions of each mode, definitions of the various descriptive labels given each mode, and techniques for optimizing and meeting the ventilator needs of the patient while avoiding complications in the surgical and critical care patient.

  18. 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.

  19. The role of dead space ventilation in predicting outcome of successful weaning from mechanical ventilation.

    PubMed

    Mohr, A M; Rutherford, E J; Cairns, B A; Boysen, P G

    2001-11-01

    The exact mechanism by which tracheostomy results in clinical improvement in respiratory function and liberation from mechanical ventilation remains unknown. Physiologic dead space, which includes both normal and abnormal components of non-gas exchange tidal volume, is a clinical measure of the efficiency of ventilation. Theoretically, tracheostomy should reduce dead space ventilation and improve pulmonary mechanics, thereby facilitating weaning from mechanical ventilation. This study compares arterial blood gases (ABG), pulmonary mechanics, including minute ventilation (VE) and dead space ventilation (Vd/Vt) within 24 hours before and after tracheostomy in 45 patients admitted to a surgical intensive care unit. There was no difference noted in patients' ABG or VE. Pre- and posttracheostomy change in Vd/Vt was negligible (50.7 and 10 vs. 51.9 and 11; p = NS). On subgroup analysis, those patients that were weaned from mechanical ventilation with 72 hours of tracheostomy (T3) were compared with those patients weaned from mechanical ventilation 5 days or more after tracheostomy (T+5). Again, no difference was found in pulmonary mechanics or Vd/Vt pre- and posttracheostomy. There is minimal improvement in pulmonary mechanics after tracheostomy. The change in physiologic dead space posttracheostomy does not predict the outcome of weaning from mechanical ventilation. Tracheostomy does allow better pulmonary toilet, and easier initiation and removal of mechanical ventilation and control of the upper airway.

  20. 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 ...

  1. 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 ...

  2. DEMAND CONTROLLED VENTILATION AND CLASSROOM VENTILATION

    SciTech Connect

    Fisk, William J.; Mendell, Mark J.; Davies, Molly; Eliseeva, Ekaterina; Faulkner, David; Hong, Tienzen; Sullivan, Douglas P.

    2014-01-06

    This document summarizes a research effort on demand controlled ventilation and classroom ventilation. The research on demand controlled ventilation included field studies and building energy modeling. Major findings included: ? The single-location carbon dioxide sensors widely used for demand controlled ventilation frequently have large errors and will fail to effectively control ventilation rates (VRs).? Multi-location carbon dioxide measurement systems with more expensive sensors connected to multi-location sampling systems may measure carbon dioxide more accurately.? Currently-available optical people counting systems work well much of the time but have large counting errors in some situations. ? In meeting rooms, measurements of carbon dioxide at return-air grilles appear to be a better choice than wall-mounted sensors.? In California, demand controlled ventilation in general office spaces is projected to save significant energy and be cost effective only if typical VRs without demand controlled ventilation are very high relative to VRs in codes. Based on the research, several recommendations were developed for demand controlled ventilation specifications in the California Title 24 Building Energy Efficiency Standards.The research on classroom ventilation collected data over two years on California elementary school classrooms to investigate associations between VRs and student illness absence (IA). Major findings included: ? Median classroom VRs in all studied climate zones were below the California guideline, and 40percent lower in portable than permanent buildings.? Overall, one additional L/s per person of VR was associated with 1.6percent less IA. ? Increasing average VRs in California K-12 classrooms from the current average to the required level is estimated to decrease IA by 3.4percent, increasing State attendance-based funding to school districts by $33M, with $6.2 M in increased energy costs. Further VR increases would provide additional benefits

  3. [Pressure support ventilation and proportional assist ventilation during weaning from mechanical ventilation].

    PubMed

    Aguirre-Bermeo, H; Bottiroli, M; Italiano, S; Roche-Campo, F; Santos, J A; Alonso, M; Mancebo, J

    2014-01-01

    To compare tolerance, duration of mechanical ventilation (MV) and clinical outcomes during weaning from MV in patients subjected to either pressure support ventilation (PSV) or proportional assist ventilation (PAV). A prospective, observational study was carried out. Intensive Care Unit. A total of 40 consecutive subjects were allocated to either the PSV or the PAV group until each group contained 20 patients. Patients were included in the study when they met the criteria to begin weaning and the attending physician decided to initiate the weaning process. The physician selected the modality and set the ventilatory parameters. None. Demographic data, respiratory mechanics, ventilatory parameters, duration of MV, and clinical outcomes (reintubation, tracheostomy, mortality). Baseline characteristics were similar in both groups. No significant differences were observed between the PSV and PAV groups in terms of the total duration of MV (10 [5-18] vs. 9 [7-19] days; P=.85), reintubation (5 [31%] vs. 3 [19%]; P=.69), or mortality (4 [20%] vs. 5 [25%] deaths; P=1). Eight patients (40%) in the PSV group and 6 patients (30%) in the PAV group (P=.74) required a return to volume assist-control ventilation due to clinical deterioration. Tolerance, duration of MV and clinical outcomes during weaning from mechanical ventilation were similar in PSV and PAV. Copyright © 2013 Elsevier España, S.L. and SEMICYUC. All rights reserved.

  4. ASSESSMENT OF RESPIRATION-INDUCED DISPLACEMENT OF CANINE ABDOMINAL ORGANS IN DORSAL AND VENTRAL RECUMBENCY USING MULTISLICE COMPUTED TOMOGRAPHY

    PubMed Central

    Oliveira, Cintia R.; Henzler, Margaret A.; Johnson, Rebecca A.; Drees, Randi

    2015-01-01

    Respiratory-induced organ displacement during image acquisition can produce motion artifacts and variation in spatial localization of an organ in diagnostic computed tomography (CT) exams. The purpose of this prospective study was to quantify respiratory-induced abdominal organ displacement in dorsal and ventral recumbency using five normal dogs. All dogs underwent CT exams using 64-multidetector-row computed tomography (MDCT). A “3-dimensional (3D) apneic CT exam” of the abdomen was acquired followed by a “4-dimensional (4D) ventilated CT exam”. The liver, pancreas, both kidneys, both medial iliac lymph nodes and urinary bladder where delineated on the 3D–apneic exam and the organ outlines were compared to the maximum alteration in organ position in the 4D–ventilated exam. Displacement was measured in dorsal-to-ventral (DV), right-to-left (RL) and cranial-to-caudal (CC) directions. Respiratory-induced displacement of canine abdominal organs was not predictable and showed large variability in the three directions evaluated. For most canine abdominal organs, dorsal recumbency provided overall the least amount of displacement among all directions evaluated except for liver and urinary bladder. For liver, a large variability was found for all directions and a statistically significant difference was found only in RL direction with ventral recumbency exhibiting less displacement (P = 0.0099). For the urinary bladder ventral recumbency also provided less displacement but this was statistically significant only in the RL direction (P < 0.0001). Findings from this study indicated that dorsal recumbency may be preferred for whole abdomen studies, but ventral recumbency may be preferred for liver and urinary bladder studies when respiration cannot be controlled. PMID:25130054

  5. [Comparison of volume preset and pressure preset ventilators during daytime nasal ventilation in chronic respiratory failure].

    PubMed

    Perrin, C; Wolter, P; Berthier, F; Tamisier, R; Jullien, V; Lemoigne, F; Blaive, B

    2001-02-01

    Both volume preset and pressure preset ventilators are available for domiciliary nasal ventilation. Owing to their technical characteristics, it has been suggested that impaired ventilatory mechanics might cause a drop in the tidal volume (Vt) delivered by pressure preset devices, thereby placing mechanical ventilation at risk of inefficacy. We have assessed two ventilator systems (one pressure preset and one volume preset) with regard to the tidal volume and end-tidal carbon dioxide tension (PetCO(2)) changes that may be achieved in a group of awake patients with stable chronic respiratory failure (CRF). Eleven patients with stable CRF were ventilated in the assist/control mode for two consecutive one-hour periods. One ventilator was tested each hour, in random order. The VIGIL'AIR(R) system was used to record Vt, Respiratory Rate (RR), and Inspiratory/Expiratory ratio (I/E). The deviation E (E=preset value - measured value) was calculated for each measurement. Changes in PetCO(2) and arterial oxygen saturation were determined respectively by a capnometer and a pulse oximeter. Comparison of the mean deviation of Vt calculated for the two ventilators revealed a difference in patients with chronic obstructive pulmonary disease (COPD). The deviation was greatest with the pressure preset ventilator (PPV), which gave mean measured values higher than the mean preset values. The same comparison failed to reveal any difference in restrictive CRF. Comparison of the volume preset and pressure preset ventilators for RR, I/E and PetCO(2) did not reveal any difference. Compared to the volume preset ventilator, the efficacy of PPV to ventilate is not affected by the restrictive or obstructive nature of CRF. Our results show that pressure-preset ventilator is an adequate alternative to the volume-preset device for daytime non invasive ventilation in chronic respiratory insufficiency.

  6. The effect of changing ventilator settings on indices of ventilation inhomogeneity in small ventilated lungs

    PubMed Central

    Schmalisch, G; Proquitté, H; Roehr, CC; Wauer, RR

    2006-01-01

    Background In ventilated newborns the use of multiple breath washout (MBW) techniques for measuring both lung volume and ventilation inhomogeneity (VI) is hampered by the comparatively high dead space fraction. We studied how changes in ventilator settings affected VI indices in this particular population. Methods Using a computer simulation of a uniformly ventilated volume the interaction between VI indices (lung clearance index (LCI), moment ratios (M1/M0, M2/M0, AMDN1, AMDN2) of the washout curve) and tidal volume (VT), dead space (VD) and functional residual capacity (FRC) were calculated. The theoretical results were compared with measurements in 15 ventilated piglets (age <12 h, median weight 1135 g) by increasing the peak inspiratory pressure (PIP). FRC and VI indices were measured by MBW using 0.8% heptafluoropropane as tracer gas. Results The computer simulation showed that the sensitivity of most VI indices to changes in VD/VT and VT/FRC increase, in particular for VD/VT > 0.5. In piglets, the raised PIP caused a significant increase of VT from 15.4 ± 9.5 to 21.9 ± 14.7 (p = 0.003) and of the FRC from 31.6 ± 14.7 mL to 35.0 ± 15.9 mL (p = 0.006), whereas LCI (9.15 ± 0.75 to 8.55 ± 0.74, p = 0.019) and the moment ratios M1/M0, M2/M0 (p < 0.02) decreased significantly. No significant changes were seen in AMDN1 and AMDN2. The within-subject variability of the VI indices (coefficient of variation in brackets) was distinctly higher (LCI (9.8%), M1/M0 (6.6%), M2/M0 (14.6%), AMDN1 (9.1%), AMDN2 (16.3%)) compared to FRC measurements (5.6%). Computer simulations showed that significant changes in VI indices were exclusively caused by changes in VT and FRC and not by an improvement of the homogeneity of alveolar ventilation. Conclusion In small ventilated lungs with a high dead space fraction, indices of VI may be misinterpreted if the changes in ventilator settings are not considered. Computer simulations can help to prevent this misinterpretation. PMID

  7. 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.

  8. New generation ventilators.

    PubMed

    Bersten, A D; Skowronski, G A; Oh, T E

    1986-08-01

    Desirable features of new generation intensive care ventilators include the ability to ventilate a wide range of patient sizes, an uncomplicated control panel, an appropriate but not excessive variety of ventilatory patterns, adequate patient monitoring and alarm functions, and simplicity of cleaning and routine maintenance. Examples of currently available ventilators include the Servo 900-C, CPU-1, Engstrom Erica, Bear 5, Drager EV-A and Hamilton Veolar. The incorporation of microcomputer control into some of these ventilators has resulted in improved flexibility and a limited number of automatic responses to detected patient changes. However, the function of components provided to allow spontaneous ventilation, such as demand valves, requires considerable improvement. Current trends in ventilator design include further refinement of computer control and the provision of graphic displays showing the results of continuous sophisticated analysis of respiratory function. The extent to which these developments will prove clinically useful will require careful evaluation.

  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. Protective garment ventilation system

    NASA Technical Reports Server (NTRS)

    Lang, R. (Inventor)

    1970-01-01

    A method and apparatus for ventilating a protective garment, space suit system, and/or pressure suits to maintain a comfortable and nontoxic atmosphere within is described. The direction of flow of a ventilating and purging gas in portions of the garment may be reversed in order to compensate for changes in environment and activity of the wearer. The entire flow of the ventilating gas can also be directed first to the helmet associated with the garment.

  11. Nonlinear optimization of buoyancy-driven ventilation flow

    NASA Astrophysics Data System (ADS)

    Nabi, Saleh; Grover, Piyush; Caulfield, C. P.

    2016-11-01

    We consider the optimization of buoyancy-driven flows governed by Boussinesq equations using the Direct-Adjoint-Looping method. We use incompressible Reynolds-averaged Navier-Stokes (RANS) equations, derive the corresponding adjoint equations and solve the resulting sensitivity equations with respect to inlet conditions. For validation, we solve a series of inverse-design problems, for which we recover known globally optimal solutions. For a displacement ventilation scenario with a line source, the numerical results are compared with analytically obtained optimal inlet conditions available from classical plume theory. Our results show that depending on Archimedes number, defined as the ratio of the inlet Reynolds number to the Rayleigh number associated with the plume, qualitatively different optimal solutions are obtained. For steady and transient plumes, and subject to an enthalpy constraint on the incoming flow, we identify boundary conditions leading to 'optimal' temperature distributions in the occupied zone.

  12. Mechanical ventilation in children.

    PubMed

    Kendirli, Tanil; Kavaz, Asli; Yalaki, Zahide; Oztürk Hişmi, Burcu; Derelli, Emel; Ince, Erdal

    2006-01-01

    Mechanical ventilation can be lifesaving, but > 50% of complications in conditions that require intensive care are related to ventilatory support, particularly if it is prolonged. We retrospectively evaluated the medical records of patients who had mechanical ventilation in the Pediatric Intensive Care Unit (PICU) during a follow-up period between January 2002-May 2005. Medical records of 407 patients were reviewed. Ninety-one patients (22.3%) were treated with mechanical ventilation. Ages of all patients were between 1-180 (median: 8) months. The mechanical ventilation time was 18.8 +/- 14.1 days. Indication of mechanical ventilation could be divided into four groups as respiratory failure (64.8%), cardiovascular failure (19.7%), central nervous system disease (9.8%) and safety airway (5.4%). Tracheostomy was performed in four patients. The complication ratio of mechanically ventilated children was 42.8%, and diversity of complications was as follows: 26.3% atelectasia, 17.5% ventilator-associated pneumonia, 13.1% pneumothorax, 5.4% bleeding, 4.3% tracheal edema, and 2.1% chronic lung disease. The mortality rate of mechanically ventilated patients was 58.3%, but the overall mortality rate in the PICU was 12.2%. In conclusion, there are few published epidemiological data on the follow-up results and mortality in infants and children who are mechanically ventilated.

  13. Angular displacement measuring device

    NASA Technical Reports Server (NTRS)

    Seegmiller, H. Lee B. (Inventor)

    1992-01-01

    A system for measuring the angular displacement of a point of interest on a structure, such as aircraft model within a wind tunnel, includes a source of polarized light located at the point of interest. A remote detector arrangement detects the orientation of the plane of the polarized light received from the source and compares this orientation with the initial orientation to determine the amount or rate of angular displacement of the point of interest. The detector arrangement comprises a rotating polarizing filter and a dual filter and light detector unit. The latter unit comprises an inner aligned filter and photodetector assembly which is disposed relative to the periphery of the polarizer so as to receive polarized light passing the polarizing filter and an outer aligned filter and photodetector assembly which receives the polarized light directly, i.e., without passing through the polarizing filter. The purpose of the unit is to compensate for the effects of dust, fog and the like. A polarization preserving optical fiber conducts polarized light from a remote laser source to the point of interest.

  14. Angular displacement measuring device

    NASA Astrophysics Data System (ADS)

    Seegmiller, H. Lee B.

    1992-08-01

    A system for measuring the angular displacement of a point of interest on a structure, such as aircraft model within a wind tunnel, includes a source of polarized light located at the point of interest. A remote detector arrangement detects the orientation of the plane of the polarized light received from the source and compares this orientation with the initial orientation to determine the amount or rate of angular displacement of the point of interest. The detector arrangement comprises a rotating polarizing filter and a dual filter and light detector unit. The latter unit comprises an inner aligned filter and photodetector assembly which is disposed relative to the periphery of the polarizer so as to receive polarized light passing the polarizing filter and an outer aligned filter and photodetector assembly which receives the polarized light directly, i.e., without passing through the polarizing filter. The purpose of the unit is to compensate for the effects of dust, fog and the like. A polarization preserving optical fiber conducts polarized light from a remote laser source to the point of interest.

  15. Ventilatory failure, ventilator support, and ventilator weaning.

    PubMed

    Tobin, Martin J; Laghi, Franco; Jubran, Amal

    2012-10-01

    The development of acute ventilatory failure represents an inability of the respiratory control system to maintain a level of respiratory motor output to cope with the metabolic demands of the body. The level of respiratory motor output is also the main determinant of the degree of respiratory distress experienced by such patients. As ventilatory failure progresses and patient distress increases, mechanical ventilation is instituted to help the respiratory muscles cope with the heightened workload. While a patient is connected to a ventilator, a physician's ability to align the rhythm of the machine with the rhythm of the patient's respiratory centers becomes the primary determinant of the level of rest accorded to the respiratory muscles. Problems of alignment are manifested as failure to trigger, double triggering, an inflationary gas-flow that fails to match inspiratory demands, and an inflation phase that persists after a patient's respiratory centers have switched to expiration. With recovery from disorders that precipitated the initial bout of acute ventilatory failure, attempts are made to discontinue the ventilator (weaning). About 20% of weaning attempts fail, ultimately, because the respiratory controller is unable to sustain ventilation and this failure is signaled by development of rapid shallow breathing. Substantial advances in the medical management of acute ventilatory failure that requires ventilator assistance are most likely to result from research yielding novel insights into the operation of the respiratory control system.

  16. Review of Residential Ventilation Technologies

    SciTech Connect

    Armin Rudd

    2005-08-30

    This paper reviews current and potential ventilation technologies for residential buildings, including a variety of mechanical systems, natural ventilation, and passive ventilation. with particular emphasis on North American climates and construction.

  17. Multifamily Ventilation Retrofit Strategies

    SciTech Connect

    Ueno, K.; Lstiburek, J.; Bergey, D.

    2012-12-01

    In multifamily buildings, central ventilation systems often have poor performance, overventilating some portions of the building (causing excess energy use), while simultaneously underventilating other portions (causing diminished indoor air quality). BSC and Innova Services Corporation performed a series of field tests at a mid-rise test building undergoing a major energy audit and retrofit, which included ventilation system upgrades.

  18. Guide to Home Ventilation

    SciTech Connect

    2010-10-01

    A fact sheet from the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy: Ventilation refers to the exchange of indoor and outdoor air. Without proper ventilation, an otherwise insulated and airtight house will seal in harmful pollutants, such as carbon monoxide, and moisture that can damage a house.

  19. SIMPLIFIED METHODS FOR COMBINING MECHANICAL VENTILATION AND NATURAL INFILTRATION

    SciTech Connect

    Modera, M.; Peterson, F.

    1985-01-01

    During the past ten years, the means of ventilating single-family residences has received considerable attention. In many areas, the use of natural ventilation for infiltration has either come under close scrutiny, or has already been supplanted by mechanical ventilation systems. To evaluate the energy efficiency and ventilation effectiveness of both mechanical and natural ventilation strategies, both complex and simplified infiltration models are used. This paper examines the inaccuracies associated with using simplified models to compare ventilation strategies. Two simplified techniques for combining mechanical ventilation flows to the flows caused by wind and stack effects are examined. The simplified combination techniques are compared with the results obtained with an iterative flow-balance simulation. The flow-balance simulation determines the ventilation by balancing the incoming and outgoing flows under the pressure conditions resulting from the combination of wind effect, stack effect and mechanical ventilation. These comparisons result in three major conclusions: (1) the commonly used flow superposition technique (flow combination in quadrature) provides better estimates of the total flow than does a technique that takes into account measured flow exponents, (2) although flow combination in quadrature overpredicts ventilation when combining wind-induced and stack-induced flows, this is not the case when mechanical ventilation is added to the picture, and (3) a simple correction for the errors caused by the simplified flow superposition technique is not easy to achieve due to the large variations in error that occur with changes in wind direction and individual flow ratios.

  20. Estimation of Lung Ventilation

    NASA Astrophysics Data System (ADS)

    Ding, Kai; Cao, Kunlin; Du, Kaifang; Amelon, Ryan; Christensen, Gary E.; Raghavan, Madhavan; Reinhardt, Joseph M.

    Since the primary function of the lung is gas exchange, ventilation can be interpreted as an index of lung function in addition to perfusion. Injury and disease processes can alter lung function on a global and/or a local level. MDCT can be used to acquire multiple static breath-hold CT images of the lung taken at different lung volumes, or with proper respiratory control, 4DCT images of the lung reconstructed at different respiratory phases. Image registration can be applied to this data to estimate a deformation field that transforms the lung from one volume configuration to the other. This deformation field can be analyzed to estimate local lung tissue expansion, calculate voxel-by-voxel intensity change, and make biomechanical measurements. The physiologic significance of the registration-based measures of respiratory function can be established by comparing to more conventional measurements, such as nuclear medicine or contrast wash-in/wash-out studies with CT or MR. An important emerging application of these methods is the detection of pulmonary function change in subjects undergoing radiation therapy (RT) for lung cancer. During RT, treatment is commonly limited to sub-therapeutic doses due to unintended toxicity to normal lung tissue. Measurement of pulmonary function may be useful as a planning tool during RT planning, may be useful for tracking the progression of toxicity to nearby normal tissue during RT, and can be used to evaluate the effectiveness of a treatment post-therapy. This chapter reviews the basic measures to estimate regional ventilation from image registration of CT images, the comparison of them to the existing golden standard and the application in radiation therapy.

  1. A theoretical model to predict both horizontal displacement and vertical displacement for electromagnetic induction-based deep displacement sensors.

    PubMed

    Shentu, Nanying; Zhang, Hongjian; Li, Qing; Zhou, Hongliang; Tong, Renyuan; Li, Xiong

    2012-01-01

    Deep displacement observation is one basic means of landslide dynamic study and early warning monitoring and a key part of engineering geological investigation. In our previous work, we proposed a novel electromagnetic induction-based deep displacement sensor (I-type) to predict deep horizontal displacement and a theoretical model called equation-based equivalent loop approach (EELA) to describe its sensing characters. However in many landslide and related geological engineering cases, both horizontal displacement and vertical displacement vary apparently and dynamically so both may require monitoring. In this study, a II-type deep displacement sensor is designed by revising our I-type sensor to simultaneously monitor the deep horizontal displacement and vertical displacement variations at different depths within a sliding mass. Meanwhile, a new theoretical modeling called the numerical integration-based equivalent loop approach (NIELA) has been proposed to quantitatively depict II-type sensors' mutual inductance properties with respect to predicted horizontal displacements and vertical displacements. After detailed examinations and comparative studies between measured mutual inductance voltage, NIELA-based mutual inductance and EELA-based mutual inductance, NIELA has verified to be an effective and quite accurate analytic model for characterization of II-type sensors. The NIELA model is widely applicable for II-type sensors' monitoring on all kinds of landslides and other related geohazards with satisfactory estimation accuracy and calculation efficiency.

  2. A Theoretical Model to Predict Both Horizontal Displacement and Vertical Displacement for Electromagnetic Induction-Based Deep Displacement Sensors

    PubMed Central

    Shentu, Nanying; Zhang, Hongjian; Li, Qing; Zhou, Hongliang; Tong, Renyuan; Li, Xiong

    2012-01-01

    Deep displacement observation is one basic means of landslide dynamic study and early warning monitoring and a key part of engineering geological investigation. In our previous work, we proposed a novel electromagnetic induction-based deep displacement sensor (I-type) to predict deep horizontal displacement and a theoretical model called equation-based equivalent loop approach (EELA) to describe its sensing characters. However in many landslide and related geological engineering cases, both horizontal displacement and vertical displacement vary apparently and dynamically so both may require monitoring. In this study, a II-type deep displacement sensor is designed by revising our I-type sensor to simultaneously monitor the deep horizontal displacement and vertical displacement variations at different depths within a sliding mass. Meanwhile, a new theoretical modeling called the numerical integration-based equivalent loop approach (NIELA) has been proposed to quantitatively depict II-type sensors’ mutual inductance properties with respect to predicted horizontal displacements and vertical displacements. After detailed examinations and comparative studies between measured mutual inductance voltage, NIELA-based mutual inductance and EELA-based mutual inductance, NIELA has verified to be an effective and quite accurate analytic model for characterization of II-type sensors. The NIELA model is widely applicable for II-type sensors’ monitoring on all kinds of landslides and other related geohazards with satisfactory estimation accuracy and calculation efficiency. PMID:22368467

  3. Ventilation of Nonparalyzed Patients Under Anesthesia with Laryngeal Mask Airway, Comparison of Three Modes of Ventilation: Volume Controlled Ventilation, Pressure Controlled Ventilation, and Pressure Controlled Ventilation-volume Guarantee

    PubMed Central

    Ghabach, Maroun Badwi; El Hajj, Elie M.; El Dib, Rouba D.; Rkaiby, Jeanette M.; Matta, May S.; Helou, May R.

    2017-01-01

    Background: Pressure controlled ventilation (PCV) is the preferable mode of ventilation of nonparalyzed patients undergoing anesthesia with laryngeal mask airway (LMA) as compared to volume controlled ventilation (VCV) and spontaneously breathing patient. In this study, we compared the PC–volume guarantee (PC-VG) mode of ventilation with VCV and PCV modes. Materials and Methods: A total of 30 patients, American Society of Anesthesiologists (ASA) physical status Classes I and II, scheduled for elective surgery under general anesthesia with a classic LMA were ventilated, subsequently, with the three modes of ventilation: VCV, PCV, and PC-VG for 10 min each mode. Tidal volume set for all patients was 8 ml/kg of ideal body weight. Parameters measured with modes of ventilation include peak inspiratory pressure (PIP), compliance, measured tidal volume, O2 saturation, end-tidal CO2, and presence of an oropharyngeal leak. Results: The PIP was significantly higher with the application of VCV mode of ventilation than PCV and PC-VG modes. The compliance was significantly lower when using the mode of ventilation VCV than PCV and PC-VG. The PIP and the compliance were not statistically different between the PCV and PC-VG modes of ventilation. Conclusions: Ventilation of nonparalyzed patients with LMA under anesthesia with PC-VG is advantageous over VCV in reducing PIP and increasing lung compliance. No difference was noted between PCV and PC-VG in ASA Classes I or II under the adequate depth of anesthesia in patients with normal pulmonary function. PMID:28298784

  4. Electrical Impedance Tomography During Mechanical Ventilation.

    PubMed

    Walsh, Brian K; Smallwood, Craig D

    2016-10-01

    Electrical impedance tomography (EIT) is a noninvasive, non-radiologic imaging modality that may be useful for the quantification of lung disorders and titration of mechanical ventilation. The principle of operation is based on changes in electrical conductivity that occur as a function of changes in lung volume during ventilation. EIT offers potentially important benefits over standard imaging modalities because the system is portable and non-radiologic and can be applied to patients for long periods of time. Rather than providing a technical dissection of the methods utilized to gather, compile, reconstruct, and display EIT images, the present article seeks to provide an overview of the clinical application of this technology as it relates to monitoring mechanical ventilation and providing decision support at the bedside. EIT has been shown to be useful in the detection of pneumothoraces, quantification of pulmonary edema and comparison of distribution of ventilation between different modes of ventilation and may offer superior individual titration of PEEP and other ventilator parameters compared with existing approaches. Although application of EIT is still primarily done within a research context, it may prove to be a useful bedside tool in the future. However, head-to-head comparisons with existing methods of mechanical ventilation titration in humans need to be conducted before its application in general ICUs can be recommended. Copyright © 2016 by Daedalus Enterprises.

  5. Assessment of mechanical ventilation parameters on respiratory mechanics.

    PubMed

    Pidaparti, Ramana M; Koombua, Kittisak; Ward, Kevin R

    2012-01-01

    Better understanding of airway mechanics is very important in order to avoid lung injuries for patients undergoing mechanical ventilation for treatment of respiratory problems in intensive-care medicine, as well as pulmonary medicine. Mechanical ventilation depends on several parameters, all of which affect the patient outcome. As there are no systematic numerical investigations of the role of mechanical ventilation parameters on airway mechanics, the objective of this study was to investigate the role of mechanical ventilation parameters on airway mechanics using coupled fluid-solid computational analysis. For the airway geometry of 3 to 5 generations considered, the simulation results showed that airflow velocity increased with increasing airflow rate. Airway pressure increased with increasing airflow rate, tidal volume and positive end-expiratory pressure (PEEP). Airway displacement and airway strains increased with increasing airflow rate, tidal volume and PEEP form mechanical ventilation. Among various waveforms considered, sine waveform provided the highest airflow velocity and airway pressure while descending waveform provided the lowest airway pressure, airway displacement and airway strains. These results combined with optimization suggest that it is possible to obtain a set of mechanical ventilation strategies to avoid lung injuries in patients.

  6. Nasal ventilation is more effective than combined oral-nasal ventilation during induction of general anesthesia in adult subjects.

    PubMed

    Liang, Yafen; Kimball, William R; Kacmarek, Robert M; Zapol, Warren M; Jiang, Yandong

    2008-06-01

    The authors hypothesized that nasal mask ventilation may be more effective than combined oral-nasal mask ventilation during induction of general anesthesia. They tested this hypothesis by comparing the volume of carbon dioxide removed per breath with nasal versus combined oral-nasal mask ventilation in nonparalyzed, apneic, adult subjects during induction of general anesthesia. Fifteen adult subjects receiving general anesthesia were ventilated first with a combined oral-nasal mask and then with only a nasal mask. The patient's head was maintained in a neutral position, without head extension or lower jaw thrust. Respiratory parameters were recorded simultaneously from both the nasal and oral masks regardless of ventilation approach. The volume of carbon dioxide removed per breath during nasal mask ventilation (median, 5.0 ml; interquartile range, 3.4-8.8 ml) was significantly larger than that during combined oral-nasal mask ventilation (median, 0.0 ml; interquartile range, 0.0-0.4 ml; P = 0.001); even the peak inspiratory airway pressure during nasal ventilation (16.7 +/- 2.7 cm H2O) was lower than that during combined oral-nasal ventilation (24.5 +/- 4.7 cm H2O; P = 0.002). The expiratory tidal volume during nasal ventilation (259.8 +/- 134.2 ml) was also larger than that during combined oral-nasal ventilation (98.9 +/- 103.4 ml; P = 0.003). Nasal mask ventilation was more effective than combined oral-nasal mask ventilation in apneic, nonparalyzed, adult subjects during induction of general anesthesia. The authors suggest that nasal mask ventilation, rather than full facemask ventilation, be considered during induction of anesthesia.

  7. 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

  8. Ventilation via cut nasotracheal tube during general anesthesia.

    PubMed

    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.

  9. CFD and ventilation research.

    PubMed

    Li, Y; Nielsen, P V

    2011-12-01

    There has been a rapid growth of scientific literature on the application of computational fluid dynamics (CFD) in the research of ventilation and indoor air science. With a 1000-10,000 times increase in computer hardware capability in the past 20 years, CFD has become an integral part of scientific research and engineering development of complex air distribution and ventilation systems in buildings. This review discusses the major and specific challenges of CFD in terms of turbulence modelling, numerical approximation, and boundary conditions relevant to building ventilation. We emphasize the growing need for CFD verification and validation, suggest ongoing needs for analytical and experimental methods to support the numerical solutions, and discuss the growing capacity of CFD in opening up new research areas. We suggest that CFD has not become a replacement for experiment and theoretical analysis in ventilation research, rather it has become an increasingly important partner. We believe that an effective scientific approach for ventilation studies is still to combine experiments, theory, and CFD. We argue that CFD verification and validation are becoming more crucial than ever as more complex ventilation problems are solved. It is anticipated that ventilation problems at the city scale will be tackled by CFD in the next 10 years. © 2011 John Wiley & Sons A/S.

  10. Displacement data assimilation

    NASA Astrophysics Data System (ADS)

    Rosenthal, W. Steven; Venkataramani, Shankar; Mariano, Arthur J.; Restrepo, Juan M.

    2017-02-01

    We show that modifying a Bayesian data assimilation scheme by incorporating kinematically-consistent displacement corrections produces a scheme that is demonstrably better at estimating partially observed state vectors in a setting where feature information is important. While the displacement transformation is generic, here we implement it within an ensemble Kalman Filter framework and demonstrate its effectiveness in tracking stochastically perturbed vortices.

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

    SciTech Connect

    Vinogradskiy, Yevgeniy; Koo, Phillip J.; Castillo, Richard; Castillo, Edward; Guerrero, Thomas; Gaspar, Laurie E.; Miften, Moyed; Kavanagh, Brian D.

    2014-05-01

    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 model 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

  12. Comparison of 4-dimensional computed tomography ventilation with nuclear medicine ventilation-perfusion imaging: a clinical validation study.

    PubMed

    Vinogradskiy, Yevgeniy; Koo, Phillip J; Castillo, Richard; Castillo, Edward; Guerrero, Thomas; Gaspar, Laurie E; Miften, Moyed; Kavanagh, Brian D

    2014-05-01

    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. 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 model 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. 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. 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

  13. A Porcine Model for Initial Surge Mechanical Ventilator Assessment and Evaluation of Two Limited Function Ventilators

    PubMed Central

    Dickson, Robert P; Hotchkin, David L; Lamm, Wayne JE; Hinkson, Carl; Pierson, David J; Glenny, Robb W; Rubinson, Lewis

    2013-01-01

    Objective To adapt an animal model of acute lung injury for use as a standard protocol for a screening, initial evaluation of limited function, or “surge,” ventilators for use in mass casualty scenarios. Design Prospective, experimental animal study. Setting University research laboratory. Subjects 12 adult pigs. Interventions 12 spontaneously breathing pigs (6 in each group) were subjected to acute lung injury/acute respiratory distress syndrome (ALI/ARDS) via pulmonary artery infusion of oleic acid. Following development of respiratory failure, animals were mechanically ventilated with a limited function ventilator (Simplified Automatic Ventilator [SAVe] I or II; Automedx) for one hour or until the ventilator could not support the animal. The limited function ventilator was then exchanged for a full function ventilator (Servo 900C; Siemens). Measurements and Main Results Reliable and reproducible levels of ALI/ARDS were induced. The SAVe I was unable to adequately oxygenate 5 animals, with PaO2 (52.0 ± 11.1 torr) compared to the Servo (106.0 ± 25.6 torr; p=0.002). The SAVe II was able to oxygenate and ventilate all 6 animals for one hour with no difference in PaO2 (141.8 ± 169.3 torr) compared to the Servo (158.3 ± 167.7 torr). Conclusions We describe a novel in vivo model of ALI/ARDS that can be used to initially screen limited function ventilators considered for mass respiratory failure stockpiles, and is intended to be combined with additional studies to defintively assess appropriateness for mass respiratory failure. Specifically, during this study we demonstrate that the SAVe I ventilator is unable to provide sufficient gas exchange, while the SAVe II, with several more functions, was able to support the same level of hypoxemic respiratory failure secondary to ALI/ARDS for one hour. PMID:21187747

  14. Does a tensioning device pinned to the tibia improve knee anterior-posterior load-displacement compared to manual tensioning of the graft following anterior cruciate ligament reconstruction? A cadaveric study of two tibial fixation devices.

    PubMed

    Thompson, Dustin M; Hull, M L; Howell, S M

    2006-09-01

    Devices that are pinned to the tibia to tension an anterior cruciate ligament (ACL) graft produce joint reaction loads that in turn can affect the maintenance of graft initial tension after tibial fixation and hence knee anterior-posterior (AP) load-displacement. However, the effect of these devices on AP load-displacement is unknown. Our objectives were to determine whether tensioning by device versus tensioning by hand causes differences in AP load-displacement and intraarticular graft tension for two commonly used tibial fixation devices: a bioresorbable interference screw and a WasherLoc. AP load-displacement and intraarticular graft tension were measured in 20 cadaveric knees using a custom arthrometer. An initial tension of 110 N was applied to a double-looped tendon graft with the knee at extension using a tensioning device pinned to the tibia and a simulated method of tensioning by hand. After inserting the tibial fixation device, the 134 N anterior limit (i.e., anterior position of the tibia with respect to the femur with a 134 N anterior force applied to the tibia) and 0 N posterior limit (i.e., AP position of the tibia relative to the femur with a 0 N force applied to the tibia) were measured with the knee in 25 degrees flexion. Intraarticular graft tension was measured at extension. These limits and intraarticular graft tension were also measured after cyclically loading the knee 300 times. Compared to a simulated method of tensioning by hand, tensioning with a device pinned to the tibia did not decrease the 134 N anterior limit and did not cause posterior tibial translation. However, intraarticular graft tension was maintained better with a tensioning device pinned to the tibia for the Washerloc, but not the interference screw. For two commonly used tibial fixation devices, a tensioning device pinned to the tibia does not improve AP load-displacement at 25 degrees flexion over tensioning by hand when the graft is tensioned at full extension, but does

  15. Ventilating Air-Conditioner

    NASA Technical Reports Server (NTRS)

    Dinh, Khanh

    1994-01-01

    Air-conditioner provides ventilation designed to be used alone or incorporated into cooling or heating system operates efficiently only by recirculating stale air within building. Energy needed to operate overall ventilating cooling or heating system slightly greater than operating nonventilating cooling or heating system. Helps to preserve energy efficiency while satisfying need for increased forced ventilation to prevent accumulation of undesired gases like radon and formaldehyde. Provides fresh treated air to variety of confined spaces: hospital surgeries, laboratories, clean rooms, and printing shops and other places where solvents used. In mobile homes and portable classrooms, eliminates irritant chemicals exuded by carpets, panels, and other materials, ensuring healthy indoor environment for occupants.

  16. Ventilating Air-Conditioner

    NASA Technical Reports Server (NTRS)

    Dinh, Khanh

    1994-01-01

    Air-conditioner provides ventilation designed to be used alone or incorporated into cooling or heating system operates efficiently only by recirculating stale air within building. Energy needed to operate overall ventilating cooling or heating system slightly greater than operating nonventilating cooling or heating system. Helps to preserve energy efficiency while satisfying need for increased forced ventilation to prevent accumulation of undesired gases like radon and formaldehyde. Provides fresh treated air to variety of confined spaces: hospital surgeries, laboratories, clean rooms, and printing shops and other places where solvents used. In mobile homes and portable classrooms, eliminates irritant chemicals exuded by carpets, panels, and other materials, ensuring healthy indoor environment for occupants.

  17. Internal displacement in Colombia

    PubMed Central

    Shultz, James M; Ceballos, Ángela Milena Gómez; Espinel, Zelde; Oliveros, Sofia Rios; Fonseca, Maria Fernanda; Florez, Luis Jorge Hernandez

    2014-01-01

    This commentary aims to delineate the distinguishing features of conflict-induced internal displacement in the nation of Colombia, South America. Even as Colombia is currently implementing a spectrum of legal, social, economic, and health programs for “victims of armed conflict,” with particular focus on internally displaced persons (IDPs), the dynamics of forced migration on a mass scale within this country are little known beyond national borders.   The authors of this commentary are embarking on a global mental health research program in Bogota, Colombia to define best practices for reaching the displaced population and implementing sustainable, evidence-based screening and intervention for common mental disorders. Presenting the defining characteristics of internal displacement in Colombia provides the context for our work and, more importantly, conveys the compelling and complex nature of this humanitarian crisis. We attempt to demonstrate Colombia’s unique position within the global patterning of internal displacement. PMID:28228997

  18. Uneven ventilation of the lung following trauma.

    PubMed Central

    Lozman, J; Dutton, R E; Newell, J; Powers, S R

    1977-01-01

    Ventilatory function of the lungs has been studied in 13 post-trauma patients using a two compartment analysis. The analysis is based upon a model of the lung which describes a nitrogen washout curve in terms of fast and slowly ventilated compartments. Data output from a digital computer provides values that compare the fractions of the alveolar ventilation and volume of the two compartments. All patients on initial investigation had large identifiable slow spaces. Subsequent evaluation at a time of clinical improvement showed that the ventilation of the slow space had increased significantly (P less than .003), whereas no change was evident in the volume fraction. The ventilation to volume ratio of the slow space, measured on these two separate occasions increased in twelve of the patients studied. An increase in this ratio correlated with improvement in the patient's clinical condition. PMID:921355

  19. Less wound complications of a sinus tarsi approach compared to an extended lateral approach for the treatment of displaced intraarticular calcaneal fracture: A randomized clinical trial in 64 patients.

    PubMed

    Li, Lian-Hua; Guo, Yong-Zhi; Wang, Hao; Sang, Qing-Hua; Zhang, Jian-Zheng; Liu, Zhi; Sun, Tian-Sheng

    2016-09-01

    We conducted a prospective randomized clinical trial to compare the clinical and radiological outcomes of the sinus tarsi and extended lateral approaches for the surgical treatment of displaced intraarticular calcaneal fractures. Between January 2009 and January 2014, patients with displaced intraarticular calcaneal fracture were randomly assigned to receive surgical treatment by the sinus tarsi approach or the extended lateral approach using block randomization. We recorded and analyzed data on demographics, time to surgery, wound complications, Böhler angles pre- and postoperatively, and American Orthopedic Foot & Ankle Society score. Sixty-four patients met the inclusion criteria and were randomly assigned to the 2 groups: 32 patients underwent sinus tarsi approach, and 32 patients the extended lateral approach. Baseline characteristics of both groups were similar. The time to surgery in the sinus tarsi approach group was significantly shorter than in the extended lateral approach group (P = 0.04). The wound complication rates were 6.3% and 31.2% in the sinus tarsi approach and extended lateral approach groups, respectively, which was significantly different (P = 0.01). Regarding the clinical outcomes, the groups did not differ significantly on walking visual analogue scale or American Orthopedic Foot & Ankle Society scores at 6 months and 1 year postoperatively. No significant differences existed between groups regarding the Böhler angle at different times and reduction quality of the articular surface and the medial wall. Compared with the extended lateral approach, the sinus tarsi approach decreased wound complications and preoperative waiting time, and achieved similar functional and radiological outcomes for displaced intraarticular calcaneal fractures.

  20. Comparing effects between music intervention and aromatherapy on anxiety of patients undergoing mechanical ventilation in the intensive care unit: a randomized controlled trial.

    PubMed

    Lee, Chiu-Hsiang; Lai, Chiung-Ling; Sung, Yi-Hui; Lai, Mei Yu; Lin, Chung-Ying; Lin, Long-Yau

    2017-07-01

    Using patient-reported outcomes and physiological indicators to test the effects of music intervention and aromatherapy on reducing anxiety for intensive care unit (ICU) patients undergoing mechanical ventilation. Patients with ICU admission duration >24 h were randomly assigned to a Music intervention group (n = 41), Aromatherapy group (n = 47), or Control group (rest only; n = 44). Each patient in the Music group listened to music; each patient in the Aromatherapy group received lavender essential oil massage on his/her back for 5 min; each patient in the Control group wore noise-canceling headphones. Anxiety was measured using the Chinese version of the Stage-Trait Anxiety Inventory (C-STAI) and the Visual Analogue Scale for Anxiety (VAS-A) at baseline, post-test, and 30-min follow-up. Heart rate, breathing rate, and blood pressure were measured every 10 min from baseline to the 30-min follow-up. The Music group had significantly better post-test VAS-A and C-STAI scores, and had lower heart rate and blood pressure than the Control group. The Aromatherapy group had significantly better VAS-A score and lower heart rate than the Control group. The 30-min follow-up showed that both Music and Aromatherapy groups had lower heart rate and blood pressure than the Control group. Music and aromatherapy interventions were both effective for ICU patients. The effects of music intervention were greater than that of aromatherapy; both interventions maintained the effects for at least 30 min.

  1. Non-invasive ventilation for cystic fibrosis.

    PubMed

    Moran, Fidelma; Bradley, Judy M; Piper, Amanda J

    2017-02-20

    Non-invasive ventilation may be a means to temporarily reverse or slow the progression of respiratory failure in cystic fibrosis by providing ventilatory support and avoiding tracheal intubation. Using non-invasive ventilation, in the appropriate situation or individuals, can improve lung mechanics through increasing airflow and gas exchange and decreasing the work of breathing. Non-invasive ventilation thus acts as an external respiratory muscle. This is an update of a previously published review. To compare the effect of non-invasive ventilation versus no non-invasive ventilation in people with cystic fibrosis for airway clearance, during sleep and during exercise. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches, handsearching relevant journals and abstract books of conference proceedings. We searched the reference lists of each trial for additional publications possibly containing other trials.Most recent search: 08 August 2016. Randomised controlled trials comparing a form of pressure preset or volume preset non-invasive ventilation to no non-invasive ventilation used for airway clearance or during sleep or exercise in people with acute or chronic respiratory failure in cystic fibrosis. Three reviewers independently assessed trials for inclusion criteria and methodological quality, and extracted data. Ten trials met the inclusion criteria with a total of 191 participants. Seven trials evaluated single treatment sessions, one evaluated a two-week intervention, one evaluated a six-week intervention and one a three-month intervention. It is only possible to blind trials of airway clearance and overnight ventilatory support to the outcome assessors. In most of the trials we judged there was an unclear risk of bias with regards to blinding due to inadequate descriptions. The six-week trial was the only one judged to have a low risk of bias for all

  2. Why We Ventilate

    SciTech Connect

    Logue, Jennifer M.; Sherman, Max H.; Price, Phil N.; Singer, Brett C.

    2011-09-01

    It is widely accepted that ventilation is critical for providing good indoor air quality (IAQ) in homes. However, the definition of"good" IAQ, and the most effective, energy efficient methods for delivering it are still matters of research and debate. This paper presents the results of work done at the Lawrence Berkeley National Lab to identify the air pollutants that drive the need for ventilation as part of a larger effort to develop a health-based ventilation standard. First, we present results of a hazard analysis that identified the pollutants that most commonly reach concentrations in homes that exceed health-based standards or guidelines for chronic or acute exposures. Second, we present results of an impact assessment that identified the air pollutants that cause the most harm to the U.S. population from chronic inhalation in residences. Lastly, we describe the implications of our findings for developing effective ventilation standards.

  3. The Impact of Ventilator-Associated Events in Critically Ill Subjects With Prolonged Mechanical Ventilation.

    PubMed

    Kobayashi, Hidetsugu; Uchino, Shigehiko; Takinami, Masanori; Uezono, Shoichi

    2017-07-18

    The Centers for Disease Control and Prevention recently released a surveillance definition for respiratory complications in ventilated patients, ventilator-associated events (VAE), to replace ventilator-associated pneumonia (VAP). VAE consists of ventilator-associated conditions (VAC), infection-related ventilator-associated complications (IVAC), and possible VAP. A duration of mechanical ventilation of at least 4 d is required to diagnose VAE. However, the observed duration of mechanical ventilation was < 4 d in many previous studies. We evaluated the impact of VAE on clinical outcomes in critically ill subjects who required mechanical ventilation for ≥ 4 d. This single-center retrospective cohort study was conducted in the general ICU of an academic hospital. We included 407 adult subjects who were admitted to the ICU and required mechanical ventilation for at least 4 d. VAC and IVAC were identified from the electronic medical records. VAP was defined according to the Centers for Disease Control and Prevention 2008 criteria and was identified from the surveillance data of the infection control team of our hospital. Clinical outcomes were studied in the VAC, IVAC, and VAP groups. Possible VAP was not investigated. Higher mortality was seen in VAC and IVAC subjects, but not in VAP subjects, compared with those without VAEs and VAP. By multivariable hazard analysis for hospital mortality, IVAC was independently associated with hospital mortality (hazard ratio 2.42, 95% CI 1.39-4.20, P = .002). VAC also tended to show a similar association with hospital mortality (hazard ratio 1.45, 95% CI 0.97-2.18, P = .07). On the other hand, VAP did not increase a hazard of hospital death (hazard ratio 1.08, 95% CI 0.44-2.66, P = .87). We found that VAE was related to hospital mortality in critically ill subjects with prolonged mechanical ventilation, and that VAP was not. Copyright © 2017 by Daedalus Enterprises.

  4. Conventional mechanical ventilation

    PubMed Central

    Tobias, Joseph D.

    2010-01-01

    The provision of mechanical ventilation for the support of infants and children with respiratory failure or insufficiency is one of the most common techniques that are performed in the Pediatric Intensive Care Unit (PICU). Despite its widespread application in the PICUs of the 21st century, before the 1930s, respiratory failure was uniformly fatal due to the lack of equipment and techniques for airway management and ventilatory support. The operating rooms of the 1950s and 1960s provided the arena for the development of the manual skills and the refinement of the equipment needed for airway management, which subsequently led to the more widespread use of endotracheal intubation thereby ushering in the era of positive pressure ventilation. Although there seems to be an ever increasing complexity in the techniques of mechanical ventilation, its successful use in the PICU should be guided by the basic principles of gas exchange and the physiology of respiratory function. With an understanding of these key concepts and the use of basic concepts of mechanical ventilation, this technique can be successfully applied in both the PICU and the operating room. This article reviews the basic physiology of gas exchange, principles of pulmonary physiology, and the concepts of mechanical ventilation to provide an overview of the knowledge required for the provision of conventional mechanical ventilation in various clinical arenas. PMID:20927268

  5. Noninvasive ventilation: practical advice.

    PubMed

    Bello, Giuseppe; De Pascale, Gennaro; Antonelli, Massimo

    2013-02-01

    This critical review discusses the key points that would be of practical help for the clinician who applies noninvasive ventilation (NIV) for treatment of patients with acute respiratory failure (ARF). In recent years, the growing role of NIV in the acute care setting has led to the development of technical innovations to overcome the problems related to gas leakage and dead space. A considerable amount of research has been conducted to improve the quality of the devices as well as optimize ventilation modes used to administer NIV. As a result, also mechanical ventilators have been implemented with modalities aimed at delivering NIV. The success of NIV in patients with ARF depends on several factors, including the skills of the clinician, selection of patient, choice of interface, selection of ventilation mode and ventilator setting, monitoring, and the motivation of the patient. Recent advances in the understanding of the physiological aspects of using NIV through different interfaces and ventilator settings have led to improve patient-machine interaction, enhancing favorable NIV outcome.

  6. The use of a displacement device negatively affects the performance of dogs (Canis familiaris) in visible object displacement tasks

    PubMed Central

    Müller, Corsin A.; Riemer, Stefanie; Range, Friederike; Huber, Ludwig

    2014-01-01

    Visible and invisible displacement tasks have been used widely for comparative studies of animals’ understanding of object permanence, with evidence accumulating that some species can solve invisible displacement tasks and thus reach Piagetian stage 6 of object permanence. In contrast, dogs appear to rely on associative cues, such as the location of the displacement device, during invisible displacement tasks. It remains unclear, however, whether dogs, and other species that failed in invisible displacement tasks, do so due to their inability to form a mental representation of the target object, or simply due to the involvement of a more salient but potentially misleading associative cue, the displacement device. Here we show that the use of a displacement device impairs the performance of dogs also in visible displacement tasks: their search accuracy was significantly lower when a visible displacement was performed with a displacement device, and only two of initially 42 dogs passed the sham-baiting control conditions. The negative influence of the displacement device in visible displacement tasks may be explained by strong associative cues overriding explicit information about the target object’s location, reminiscent of an overshadowing effect, and/or object individuation errors as the target object is placed within the displacement device and moves along a spatiotemporally identical trajectory. Our data suggest that a comprehensive appraisal of a species’ performance in object permanence tasks should include visible displacement tasks with the same displacement device used in invisible displacements, which typically has not been done in the past. PMID:24611641

  7. The use of a displacement device negatively affects the performance of dogs (Canis familiaris) in visible object displacement tasks.

    PubMed

    Müller, Corsin A; Riemer, Stefanie; Range, Friederike; Huber, Ludwig

    2014-08-01

    Visible and invisible displacement tasks have been used widely for comparative studies of animals' understanding of object permanence, with evidence accumulating that some species can solve invisible displacement tasks and, thus, reach Piagetian stage 6 of object permanence. In contrast, dogs appear to rely on associative cues, such as the location of the displacement device, during invisible displacement tasks. It remains unclear, however, whether dogs, and other species that failed in invisible displacement tasks, do so because of their inability to form a mental representation of the target object, or simply because of the involvement of a more salient but potentially misleading associative cue, the displacement device. Here we show that the use of a displacement device impairs the performance of dogs also in visible displacement tasks: their search accuracy was significantly lower when a visible displacement was performed with a displacement device, and only two of initially 42 dogs passed the sham-baiting control conditions. The negative influence of the displacement device in visible displacement tasks may be explained by strong associative cues overriding explicit information about the target object's location, reminiscent of an overshadowing effect, and/or object individuation errors as the target object is placed within the displacement device and moves along a spatiotemporally identical trajectory. Our data suggest that a comprehensive appraisal of a species' performance in object permanence tasks should include visible displacement tasks with the same displacement device used in invisible displacements, which typically has not been done in the past.

  8. Remifentanil-propofol analgo-sedation shortens duration of ventilation and length of ICU stay compared to a conventional regimen: a centre randomised, cross-over, open-label study in the Netherlands.

    PubMed

    Rozendaal, F Willem; Spronk, Peter E; Snellen, Ferdinand F; Schoen, Adri; van Zanten, Arthur R H; Foudraine, Norbert A; Mulder, Paul G H; Bakker, Jan

    2009-02-01

    Compare duration of mechanical ventilation (MV), weaning time, ICU-LOS (ICU-LOS), efficacy and safety of remifentanil-based regimen with conventional sedation and analgesia. Centre randomised, open-label, crossover, 'real-life' study. 15 Dutch hospitals. Adult medical and post-surgical ICU patients with anticipated short-term (2-3 days) MV. Patient cohorts were randomised to remifentanil-based regimen (n = 96) with propofol as required, for a maximum of 10 days, or to conventional regimens (n = 109) of propofol, midazolam or lorazepam combined with fentanyl or morphine. Outcomes were weaning time, duration of MV, ICU-LOS, sedation- and analgesia levels, intensivist/ICU nurse satisfaction, adverse events, mean arterial pressure, heart rate. Median duration of ventilation (MV) was 5.1 days with conventional treatment versus 3.9 days with remifentanil (NS). The remifentanil-based regimen reduced median weaning time by 18.9 h (P = 0.0001). Median ICU-LOS was 7.9 days versus 5.9 days, respectively (NS). However, the treatment effects on duration of MV and ICU stay were time-dependent: patients were almost twice as likely to be extubated (P = 0.018) and discharged from the ICU (P = 0.05) on day 1-3. Propofol doses were reduced by 20% (P = 0.05). Remifentanil also improved sedation-agitation scores (P < 0.0001) and intensivist/ICU nurse satisfaction (P < 0.0001). All other outcomes were comparable. In patients with an expected short-term duration of MV, remifentanil significantly improves sedation and agitation levels and reduces weaning time. This contributes to a shorter duration of MV and ICU-LOS.

  9. Sensor-based demand controlled ventilation

    SciTech Connect

    De Almeida, A.T.; Fisk, W.J.

    1997-07-01

    In most buildings, occupancy and indoor pollutant emission rates vary with time. With sensor-based demand-controlled ventilation (SBDCV), the rate of ventilation (i.e., rate of outside air supply) also varies with time to compensate for the changes in pollutant generation. In other words, SBDCV involves the application of sensing, feedback and control to modulate ventilation. Compared to ventilation without feedback, SBDCV offers two potential advantages: (1) better control of indoor pollutant concentrations; and (2) lower energy use and peak energy demand. SBDCV has the potential to improve indoor air quality by increasing the rate of ventilation when indoor pollutant generation rates are high and occupants are present. SBDCV can also save energy by decreasing the rate of ventilation when indoor pollutant generation rates are low or occupants are absent. After providing background information on indoor air quality and ventilation, this report provides a relatively comprehensive discussion of SBDCV. Topics covered in the report include basic principles of SBDCV, sensor technologies, technologies for controlling air flow rates, case studies of SBDCV, application of SBDCV to laboratory buildings, and research needs. SBDCV appears to be an increasingly attractive technology option. Based on the review of literature and theoretical considerations, the application of SBDCV has the potential to be cost-effective in applications with the following characteristics: (a) a single or small number of dominant pollutants, so that ventilation sufficient to control the concentration of the dominant pollutants provides effective control of all other pollutants; (b) large buildings or rooms with unpredictable temporally variable occupancy or pollutant emission; and (c) climates with high heating or cooling loads or locations with expensive energy.

  10. Advanced Controls for Residential Whole-House Ventilation Systems

    SciTech Connect

    Turner, William; Walker, Iain; Sherman, Max

    2014-08-01

    Whole-house ventilation systems are becoming commonplace in new construction, remodeling/renovation, and weatherization projects, driven by combinations of specific requirements for indoor air quality (IAQ), health and compliance with standards, such as ASHRAE 62.2. Ventilation systems incur an energy penalty on the home via fan power used to drive the airflow, and the additional space-conditioning load associated with heating or cooling the ventilation air. Finding a balance between IAQ and energy use is important if homes are to be adequately ventilated while not increasing the energy burden. This study used computer simulations to examine RIVEC the Residential Integrated Ventilation Controller - a prototype ventilation controller that aims to deliver whole-house ventilation rates that comply with ventilation standards, for the minimum use of energy. Four different whole-house ventilation systems were simulated, both with and without RIVEC, so that the energy and IAQ results could be compared. Simulations were conducted for 13 US climate zones, three house designs, and three envelope leakage values. The results showed that the RIVEC controller could typically return ventilation energy savings greater than 40percent without compromising long-term chronic or short-term acute exposures to relevant indoor contaminants. Critical and average peak power loads were also reduced as a consequence of using RIVEC.

  11. Iraqi Population Displacement Analysis

    DTIC Science & Technology

    2016-11-01

    4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with...NOTES 14. ABSTRACT The purpose of this study was to inform CJ34 Civil Military Operations decisions on placement of internally displaced person (IDP...IDPs stay in locations that are not aligned with their ethno-religious majority. 15. SUBJECT TERMS Internally Displaced Person (IDP), Iraq

  12. Advanced Triangulation Displacement Sensors

    NASA Technical Reports Server (NTRS)

    Poteet, Wade M.; Cauthen, Harold K.

    1996-01-01

    Advanced optoelectronic triangulation displacement sensors undergoing development. Highly miniaturized, more stable, more accurate, and relatively easy to use. Incorporate wideband electronic circuits suitable for real-time monitoring and control of displacements. Measurements expected to be accurate to within nanometers. In principle, sensors mass-produced at relatively low unit cost. Potential applications numerous. Possible industrial application in measuring runout of rotating shaft or other moving part during fabrication in "zero-defect" manufacturing system, in which measured runout automatically corrected.

  13. Advanced Triangulation Displacement Sensors

    NASA Technical Reports Server (NTRS)

    Poteet, Wade M.; Cauthen, Harold K.

    1996-01-01

    Advanced optoelectronic triangulation displacement sensors undergoing development. Highly miniaturized, more stable, more accurate, and relatively easy to use. Incorporate wideband electronic circuits suitable for real-time monitoring and control of displacements. Measurements expected to be accurate to within nanometers. In principle, sensors mass-produced at relatively low unit cost. Potential applications numerous. Possible industrial application in measuring runout of rotating shaft or other moving part during fabrication in "zero-defect" manufacturing system, in which measured runout automatically corrected.

  14. Internal displacement in Burma.

    PubMed

    Lanjouw, S; Mortimer, G; Bamforth, V

    2000-09-01

    The internal displacement of populations in Burma is not a new phenomenon. Displacement is caused by numerous factors. Not all of it is due to outright violence, but much is a consequence of misguided social and economic development initiatives. Efforts to consolidate the state by assimilating populations in government-controlled areas by military authorities on the one hand, while brokering cease-fires with non-state actors on the other, has uprooted civilian populations throughout the country. Very few areas in which internally displaced persons (IDPs) are found are not facing social turmoil within a climate of impunity. Humanitarian access to IDP populations remains extremely problematic. While relatively little information has been collected, assistance has been focused on targeting accessible groups. International concern within Burma has couched the problems of displacement within general development modalities, while international attention along its borders has sought to contain displacement. With the exception of several recent initiatives, few approaches have gone beyond assistance and engaged in the prevention or protection of the displaced.

  15. 14 CFR 25.831 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Ventilation and Heating § 25.831 Ventilation... probable failures or malfunctioning of the ventilating, heating, pressurization, or other systems...

  16. 14 CFR 25.831 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Ventilation and Heating § 25.831 Ventilation... probable failures or malfunctioning of the ventilating, heating, pressurization, or other systems...

  17. 14 CFR 25.831 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Ventilation and Heating § 25.831 Ventilation... probable failures or malfunctioning of the ventilating, heating, pressurization, or other systems...

  18. 14 CFR 25.831 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Ventilation and Heating § 25.831 Ventilation... probable failures or malfunctioning of the ventilating, heating, pressurization, or other systems...

  19. Pulmonary ventilation defects in older never-smokers.

    PubMed

    Sheikh, Khadija; Paulin, Gregory A; Svenningsen, Sarah; Kirby, Miranda; Paterson, Nigel A M; McCormack, David G; Parraga, Grace

    2014-08-01

    Hyperpolarized (3)He MRI previously revealed spatially persistent ventilation defects in healthy, older compared with healthy, younger never-smokers. To understand better the physiological consequences and potential relevance of (3)He MRI ventilation defects, we evaluated (3)He-MRI ventilation-defect percent (VDP) and the effect of deep inspiration (DI) and salbutamol on VDP in older never-smokers. To identify the potential determinants of ventilation defects in these subjects, we evaluated dyspnea, pulmonary function, and cardiopulmonary exercise test (CPET) measurements, as well as occupational and second-hand smoke exposure. Fifty-two never-smokers (71 ± 6 yr) with no history of chronic respiratory disease were evaluated. During a single visit, pulmonary function tests, CPET, and (3)He MRI were performed and the Burden of Obstructive Lung Disease questionnaire administered. For eight of 52 subjects, there was spirometry evidence of airflow limitation (Global Initiative for Chronic Obstructive Lung Disease-Unclassified, I, and II), and occupational exposure was reported in 13 of 52 subjects. In 13 of 52 (25%) subjects, there were no ventilation defects and in 39 of 52 (75%) subjects, ventilation defects were observed. For those subjects with ventilation defects, six of 39 showed a VDP response to DI/salbutamol. Ventilation heterogeneity and VDP were significantly greater, and forced expiratory volume in 1 s (FEV1)/forced vital capacity was significantly lower (P < 0.05) for subjects with ventilation defects with a response to DI/salbutamol than subjects with ventilation defects without a response to DI/salbutamol and subjects without ventilation defects. In a step-wise, forward multivariate model, FEV1, inspiratory capacity, and airway resistance significantly predicted VDP (R(2) = 0.45, P < 0.001). In conclusion, most never-smokers had normal spirometry and peripheral ventilation defects not reversed by DI/salbutamol; such ventilation defects were likely

  20. Air flow and particle control with different ventilation systems in a classroom.

    PubMed

    Holmberg, S; Chen, Q

    2003-06-01

    Most ventilation and air conditioning systems are designed without much concern about how settling particles behave in ventilation air flows. For displacement ventilation systems, designers normally assume that all pollutants follow the buoyant air flow into an upper zone, where they are evacuated. This is, however, not always true. Previous studies show that high concentrations of settling respirable particles can be found in the breathing zone, and that the exposure rates can be a health hazard to occupants. The emphasis here is on how ventilation systems should be designed to minimize respirable airborne particles in the breathing zone. The supply and exhaust conditions of the ventilation air flow are shown to play an important role in the control of air quality. Computer simulation programs of computational fluid dynamics (CFD) type are used. Particle concentrations, thermal conditions and modified ventilation system solutions are reported.

  1. Weaning from artificial ventilation.

    PubMed

    Mancebo, J

    1998-06-01

    Every intubated and mechanically-ventilated patient should be clinically evaluated, at least on a daily basis, by a skilled team in order to speed up the weaning process as much as possible. Again, it should be emphasized that the adoption of an active clinical strategy when faced with "difficult" to wean patients is of paramount importance. In one study, performed in Spain, analysing the prevalence of mechanical ventilation in intensive care units [3], reported the mean number of days that patients spent on mechanical ventilation was 27. In a more recent intervention study, in which a specific protocol was followed each day [2], the mean number of days on mechanical ventilation was only 12. These data have been confirmed by several authors [4, 40], and it has also been reported that a protocol-directed weaning strategy leads not only to a significant reduction in the duration of mechanical ventilation but also to a significant decrease in the number of complications and cost [4]. However, even following a protocol-directed weaning strategy, it is possible that weaning duration can be further reduced. In a prospective study performed in our institution [41] during 32 months, we reported that, following an episode of unplanned extubation, the only independent variables associated with the need for reintubation were the number of days of mechanical ventilation and the type of ventilatory support at the time of autoextubation. Indeed, when patients were in the weaning period only 16% (5 out of 32) needed reintubation, whereas reintubation was needed in 82% (22 out of 27) of patients who had an unplanned extubation during full mechanical ventilatory support. These data suggest that there are still some patients being on mechanical ventilation for a longer than necessary period of time. Finally, very recent advances in technological areas such as artificial intelligence, are proving to be useful in the management of the weaning process. When such systems are applied to

  2. The effects of an automatic, low pressure and constant flow ventilation device versus manual ventilation during cardiovascular resuscitation in a porcine model of cardiac arrest.

    PubMed

    Hu, Xudong; Ramadeen, Andrew; Laurent, Gabriel; So, Petsy Pui-Sze; Baig, Ehtesham; Hare, Gregory M T; Dorian, Paul

    2013-08-01

    Cardiac arrest is an important cause of mortality. Cardiopulmonary resuscitation (CPR) improves survival, however, delivery of effective CPR can be challenging and combining effective chest compressions with ventilation, while avoiding over-ventilation is difficult. We hypothesized that ventilation with a pneumatically powered, automatic ventilator (Oxylator(®)) can provide adequate ventilation in a model of cardiac arrest and improve the consistency of ventilations during CPR. Twelve pigs (∼40 kg, either sex) underwent 3 episodes each of cardiac arrest and resuscitation consisting of 30s of untreated ventricular fibrillation, followed by 5 min of CPR, defibrillation, and ∼30 min of recovery. During CPR in each episode, pigs were ventilated in 1 of 3 ways in random balanced order: manual ventilation using AMBU bag (12 breaths/min), low pressure Oxylator(®) (maximum airway pressure 15 cm H2O with 20 L/min constant flow in automatic mode [Ox15/20]), or high pressure Oxylator(®) (maximum airway pressure 20 cm H2O with 30 L/min constant flow in automatic mode [Ox20/30]). During CPR, both Ox15/20 and Ox20/30 resulted in higher levels of positive end expiratory pressure than manual ventilation. Ox15/20 ventilation also resulted in higher arterial pCO2 than manual ventilation. Ox20/30 ventilation yielded higher arterial pO2 and a lower arterial-alveolar gradient than manual ventilation. All pigs were successfully defibrillated, and no measured haemodynamic variables were different between the groups. Ventilation with an automatic ventilation device during CPR is feasible and provides adequate ventilation and comparable haemodynamics when compared to manual bag ventilation. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  3. 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

  4. Competition between Displacement and Dissociation of a Strong Acid Compared to a Weak Acid Adsorbed on Silica Particle Surfaces: The Role of Adsorbed Water.

    PubMed

    Fang, Yuan; Tang, Mingjin; Grassian, Vicki H

    2016-06-16

    The adsorption of nitric (HNO3) and formic (HCOOH) acids on silica particle surfaces and the effect of adsorbed water have been investigated at 296 K using transmission FTIR spectroscopy. Under dry conditions, both nitric and formic acids adsorb reversibly on silica. Additionally, the FTIR spectra show that both of these molecules remain in the protonated form. At elevated relative humidities (RH), adsorbed water competes both for surface adsorption sites with these acids as well as promotes their dissociation to hydronium ions and the corresponding anions. Compared to HNO3, the extent of dissociation is much smaller for HCOOH, very likely because it is a weaker acid. This study provides valuable insights into the interaction of HNO3 and HCOOH with silica surface on the molecular level and further reveals the complex roles of surface-adsorbed water in atmospheric heterogeneous chemistry of mineral dust particles-many of these containing silica.

  5. Ventilation technologies scoping study

    SciTech Connect

    Walker, Iain S.; Sherman, Max H.

    2003-09-30

    This document presents the findings of a scoping study commissioned by the Public Interest Energy Research (PIER) program of the California Energy Commission to determine what research is necessary to develop new residential ventilation requirements for California. This study is one of three companion efforts needed to complete the job of determining the needs of California, determining residential ventilation requirements, and determining appropriate ventilation technologies to meet these needs and requirements in an energy efficient manner. Rather than providing research results, this scoping study identifies important research questions along with the level of effort necessary to address these questions and the costs, risks, and benefits of pursuing alternative research questions. In approaching these questions and level of effort, feasibility and timing were important considerations. The Commission has specified Summer 2005 as the latest date for completing this research in time to update the 2008 version of California's Energy Code (Title 24).

  6. Ventilation flow: Submerged

    NASA Technical Reports Server (NTRS)

    Hutchinson, D.

    1985-01-01

    The ventilation system on a submarine is discussed. When the submarine is submerged. The ventilation system provides a conditioned atmosphere in the ship with complete isolation from the outside. A conditioned atmosphere includes not only filtration and temperature and humidity control, but also air purification (removal of potentially harmful quantities of impurities and comtaminants) and revitalization (addition of vital life support oxygen). Carbon dioxide removal, the oxygen system, air conditioning, carbon monoxide removal, hydrogen removal, and atmosphere monitoring systems are among the topics discussed.

  7. Meeting Residential Ventilation Standards Through Dynamic Control of Ventilation Systems

    SciTech Connect

    Sherman, Max H.; Walker, Iain S.

    2011-04-01

    Existing ventilation standards, including American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) Standard 62.2, specify continuous operation of a defined mechanical ventilation system to provide minimum ventilation, with time-based intermittent operation as an option. This requirement ignores several factors and concerns including: other equipment such as household exhaust fans that might incidentally provide ventilation, negative impacts of ventilation when outdoor pollutant levels are high, the importance of minimizing energy use particularly during times of peak electricity demand, and how the energy used to condition air as part of ventilation system operation changes with outdoor conditions. Dynamic control of ventilation systems can provide ventilation equivalent to or better than what is required by standards while minimizing energy costs and can also add value by shifting load during peak times and reducing intake of outdoor air contaminants. This article describes the logic that enables dynamic control of whole-house ventilation systems to meet the intent of ventilation standards and demonstrates the dynamic ventilation system control concept through simulations and field tests of the Residential Integrated Ventilation-Energy Controller (RIVEC).

  8. Intelligent decision support systems for mechanical ventilation.

    PubMed

    Tehrani, Fleur T; Roum, James H

    2008-11-01

    An overview of different methodologies used in various intelligent decision support systems (IDSSs) for mechanical ventilation is provided. The applications of the techniques are compared in view of today's intensive care unit (ICU) requirements. Information available in the literature is utilized to provide a methodological review of different systems. Comparisons are made of different systems developed for specific ventilation modes as well as those intended for use in wider applications. The inputs and the optimized parameters of different systems are discussed and rule-based systems are compared to model-based techniques. The knowledge-based systems used for closed-loop control of weaning from mechanical ventilation are also described. Finally, in view of increasing trend towards automation of mechanical ventilation, the potential utility of intelligent advisory systems for this purpose is discussed. IDSSs for mechanical ventilation can be quite helpful to clinicians in today's ICU settings. To be useful, such systems should be designed to be effective, safe, and easy to use at patient's bedside. In particular, these systems must be capable of noise removal, artifact detection and effective validation of data. Systems that can also be adapted for closed-loop control/weaning of patients at the discretion of the clinician, may have a higher potential for use in the future.

  9. Optical displacement sensor

    DOEpatents

    Carr, Dustin W.

    2008-04-08

    An optical displacement sensor is disclosed which uses a vertical-cavity surface-emitting laser (VCSEL) coupled to an optical cavity formed by a moveable membrane and an output mirror of the VCSEL. This arrangement renders the lasing characteristics of the VCSEL sensitive to any movement of the membrane produced by sound, vibrations, pressure changes, acceleration, etc. Some embodiments of the optical displacement sensor can further include a light-reflective diffractive lens located on the membrane or adjacent to the VCSEL to control the amount of lasing light coupled back into the VCSEL. A photodetector detects a portion of the lasing light from the VCSEL to provide an electrical output signal for the optical displacement sensor which varies with the movement of the membrane.

  10. Water displacement mercury pump

    DOEpatents

    Nielsen, M.G.

    1984-04-20

    A water displacement mercury pump has a fluid inlet conduit and diffuser, a valve, a pressure cannister, and a fluid outlet conduit. The valve has a valve head which seats in an opening in the cannister. The entire assembly is readily insertable into a process vessel which produces mercury as a product. As the mercury settles, it flows into the opening in the cannister displacing lighter material. When the valve is in a closed position, the pressure cannister is sealed except for the fluid inlet conduit and the fluid outlet conduit. Introduction of a lighter fluid into the cannister will act to displace a heavier fluid from the cannister via the fluid outlet conduit. The entire pump assembly penetrates only a top wall of the process vessel, and not the sides or the bottom wall of the process vessel. This insures a leak-proof environment and is especially suitable for processing of hazardous materials.

  11. Water displacement mercury pump

    DOEpatents

    Nielsen, Marshall G.

    1985-01-01

    A water displacement mercury pump has a fluid inlet conduit and diffuser, a valve, a pressure cannister, and a fluid outlet conduit. The valve has a valve head which seats in an opening in the cannister. The entire assembly is readily insertable into a process vessel which produces mercury as a product. As the mercury settles, it flows into the opening in the cannister displacing lighter material. When the valve is in a closed position, the pressure cannister is sealed except for the fluid inlet conduit and the fluid outlet conduit. Introduction of a lighter fluid into the cannister will act to displace a heavier fluid from the cannister via the fluid outlet conduit. The entire pump assembly penetrates only a top wall of the process vessel, and not the sides or the bottom wall of the process vessel. This insures a leak-proof environment and is especially suitable for processing of hazardous materials.

  12. Pulmonary ventilation/perfusion scan

    MedlinePlus

    ... JavaScript. A pulmonary ventilation/perfusion scan involves two nuclear scan tests to measure breathing (ventilation) and circulation ( ... In: Mettler FA, Guiberteau MJ, eds. Essentials of Nuclear Medicine Imaging . 6th ed. Philadelphia, PA: Elsevier Saunders; ...

  13. Central Fan Integrated Ventilation Systems

    SciTech Connect

    2009-05-12

    This information sheet describes one example of a ventilation system design, a central fan integrated supply (CFIS) system, a mechanical ventilation and pollutant source control to ensure that there is reasonable indoor air quality inside the house.

  14. Infusion of 2.5 meq/min of lactic acid minimally increases CO2 production compared to an isocaloric glucose infusion in healthy anesthetized, mechanically ventilated pigs

    PubMed Central

    2013-01-01

    Introduction Blood acidification by lactic acid infusion converts bicarbonate to CO2. This effect can be exploited to increase the transmembrane PCO2 gradient of an extracorporeal membrane lung, resulting in a significant increase of extracorporeal CO2 removal. Lactic acid, however, is an energetic substrate and its metabolism might increase total body CO2 production (VCO2), limiting the potential beneficial effects of this technique. The aim of our study was to compare VCO₂ during isocaloric infusion of lactic acid or glucose. Methods Six pigs (45 ± 5 kg) were sedated and mechanically ventilated. Estimated caloric needs were 2,300–2,400 Kcal/die (95 to 100 Kcal/h). A sequence of two steps lasting four hours each was performed: 1) Glucose, 97 kcal/h were administered as 50% glucose solution, and 2) Lactic Acid, approximately 48.5 kcal/h were administered as lactic acid and approximately 48.5 kcal/h as 50% glucose solution. This sequence was repeated three times with two-hour intervals. Every hour VCO₂, arterial blood gases and lactate were measured. Blood glucose level was kept constant by titrating an insulin infusion, ventilation was adjusted to maintain arterial PCO2 at 50 mmHg, a normal value for our animal model. Results During Lactic Acid steps VCO2 increased less than 5% compared to the Glucose steps (282 vs. 269 ml/min, P <0.05); blood glucose did not differ between the two groups (respectively 101 ± 12 vs. 103 ± 8 mg/dl). Arterial lactate was always lower than 3 mmol/L. Arterial pH was lower during Lactic Acid steps (7.422 vs. 7.445, P <0.05). Conclusions Replacing 50% of the caloric input with lactic acid increased total CO2 production by less than 5% compared to an equal caloric load provided entirely by a 50% glucose solution. PMID:24209456

  15. 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

  16. Recommended Ventilation Strategies for Energy-Efficient Production Homes

    SciTech Connect

    Roberson, J.; Brown, R.; Koomey, J.; Warner, J.; Greenberg, S.

    1998-12-01

    This report evaluates residential ventilation systems for the U.S. Environmental Protection Agency's (EPA's) ENERGY STAR{reg_sign} Homes program and recommends mechanical ventilation strategies for new, low-infiltration, energy-efficient, single-family, ENERGY STAR production (site-built tract) homes in four climates: cold, mixed (cold and hot), hot humid, and hot arid. Our group in the Energy Analysis Department at Lawrence Berkeley National Lab compared residential ventilation strategies in four climates according to three criteria: total annualized costs (the sum of annualized capital cost and annual operating cost), predominant indoor pressure induced by the ventilation system, and distribution of ventilation air within the home. The mechanical ventilation systems modeled deliver 0.35 air changes per hour continuously, regardless of actual infiltration or occupant window-opening behavior. Based on the assumptions and analysis described in this report, we recommend independently ducted multi-port supply ventilation in all climates except cold because this strategy provides the safety and health benefits of positive indoor pressure as well as the ability to dehumidify and filter ventilation air. In cold climates, we recommend that multi-port supply ventilation be balanced by a single-port exhaust ventilation fan, and that builders offer balanced heat-recovery ventilation to buyers as an optional upgrade. For builders who continue to install forced-air integrated supply ventilation, we recommend ensuring ducts are airtight or in conditioned space, installing a control that automatically operates the forced-air fan 15-20 minutes during each hour that the fan does not operate for heating or cooling, and offering ICM forced-air fans to home buyers as an upgrade.

  17. Rethinking hospital general ward ventilation design using computational fluid dynamics.

    PubMed

    Yam, R; Yuen, P L; Yung, R; Choy, T

    2011-01-01

    Indoor ventilation with good air quality control minimises the spread of airborne respiratory and other infections in hospitals. This article considers the role of ventilation in preventing and controlling infection in hospital general wards and identifies a simple and cost-effective ventilation design capable of reducing the chances of cross-infection. Computational fluid dynamic (CFD) analysis is used to simulate and compare the removal of microbes using a number of different ventilation systems. Instead of the conventional corridor air return arrangement used in most general wards, air return is rearranged so that ventilation is controlled from inside the ward cubicle. In addition to boosting the air ventilation rate, the CFD results reveal that ventilation performance and the removal of microbes can be significantly improved. These improvements are capable of matching the standards maintained in a properly constructed isolation room, though at much lower cost. It is recommended that the newly identified ventilation parameters be widely adopted in the design of new hospital general wards to minimise cross-infection. The proposed ventilation system can also be retrofitted in existing hospital general wards with far less disruption and cost than a full-scale refurbishment. Copyright © 2010 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved.

  18. 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.

  19. How to Plan Ventilation Systems.

    ERIC Educational Resources Information Center

    Clarke, John H.

    1963-01-01

    Ventilation systems for factory safety demand careful planning. The increased heat loads and new processes of industry have introduced complex ventilation problems in--(1) ventilation supply, (2) duct work design, (3) space requirements, (4) hood face velocities, (5) discharge stacks, and (6) building eddies. This article describes and diagrams…

  20. How to Plan Ventilation Systems.

    ERIC Educational Resources Information Center

    Clarke, John H.

    1963-01-01

    Ventilation systems for factory safety demand careful planning. The increased heat loads and new processes of industry have introduced complex ventilation problems in--(1) ventilation supply, (2) duct work design, (3) space requirements, (4) hood face velocities, (5) discharge stacks, and (6) building eddies. This article describes and diagrams…

  1. Measure Guideline: Ventilation Cooling

    SciTech Connect

    Springer, D.; Dakin, B.; German, A.

    2012-04-01

    The purpose of this measure guideline on ventilation cooling is to provide information on a cost-effective solution for reducing cooling system energy and demand in homes located in hot-dry and cold-dry climates. This guideline provides a prescriptive approach that outlines qualification criteria, selection considerations, and design and installation procedures.

  2. Non-invasive ventilation.

    PubMed Central

    Spence, D.

    1996-01-01

    Nasal intermittent positive pressure ventilation is an effective treatment for nocturnal hypoventilation secondary to chest wall deformity or respiratory muscle weakness. Physicians should be aware that, in these groups of patients, disabling breathlessness can be alleviated and established cor pulmonale reversed by the technique. Images Figure 1 Figure 2 Figure 3 PMID:8949588

  3. Ventilator-associated pneumonia.

    PubMed

    Morehead, R S; Pinto, S J

    2000-07-10

    Ventilator-associated pneumonia is a common complication in intensive care units, occurring in 9% to 24% of patients intubated for longer than 48 hours. Because of this large disease burden and the resultant attributable morbidity and mortality, there is great interest in accurately diagnosing, treating, and preventing this complication. More severely ill patients tend to develop ventilator-associated pneumonia, and identified risk factors include prolonged mechanical ventilation, reintubation after failed extubation, and a few other clinical variables. The efficacy of diagnostic and preventive strategies is somewhat controversial. Diagnosis by invasive methods requires a considerable commitment of resources but can potentially reduce cost of care; however, mortality benefit from this approach has not been demonstrated. As such, in most institutions, ventilator-associated pneumonia is best diagnosed using traditional clinical criteria. Prompt administration of appropriate antibiotics seems to be the only intervention that alters outcome once the diagnosis is established. Several strategies seem to reduce pneumonia incidence; however, mortality and cost benefits have yet to be convincingly shown.

  4. Energy recovery ventilator

    SciTech Connect

    Schneider, S. L.; Dravnieks, K.

    1985-04-30

    An energy recovery ventilator adapted to be mounted on a roof and adapted to be connected to the outlet of an exhaust air duct of a building ventilation system and the inlet of an air supply duct of a building ventilation system. The energy recovery ventilator includes a housing having an exhaust air chamber and a supply air chamber separated by a divider wall. A circular heat transfer wheel is position in the housing, a portion of the wheel being housed in the exhaust air chamber and a second portion of the wheel being housed in the supply air chamber, and the heat transfer wheel is caused to rotate about a central axis. An exhaust fan is housed in the exhaust air chamber and causes exhaust air to be pulled through the exhaust air duct and the heat transfer wheel and to be exhausted from the housing. A supply air fan is housed in the supply air housing above the heat transfer wheel, and causes outside air to be drawn into the supply air chamber and to be forced through the heat transfer wheel into the air supply duct.

  5. Understanding mechanical ventilators.

    PubMed

    Chatburn, Robert L

    2010-12-01

    The respiratory care academic community has not yet adopted a standardized system for classifying and describing modes of ventilation. As a result, there is enough confusion that patient care, clinician education and even ventilator sales are all put at risk. This article summarizes a ventilator mode taxonomy that has been extensively published over the last 15 years. Specifically, the classification system has three components: a description of the control variables within breath; a description of the sequence of mandatory and spontaneous breaths; and a specification for the targeting scheme. This three-level specification provides scalability of detail to make the mode description appropriate for the particular need. At the bedside, we need only refer to a mode briefly using the first or perhaps first and second components. To distinguish between similar modes and brand names, we would need to include all components. This taxonomy uses the equation of motion for the respiratory system as the underlying theoretical framework. All terms relevant to describing modes of mechanical ventilation are defined in an extensive appendix.

  6. Laboratory Ventilation and Safety.

    ERIC Educational Resources Information Center

    Steere, Norman V.

    1965-01-01

    In order to meet the needs of both safety and economy, laboratory ventilation systems must effectively remove air-borne toxic and flammable materials and at the same time exhaust a minimum volume of air. Laboratory hoods are the most commonly used means of removing gases, dusts, mists, vapors, and fumed from laboratory operations. To be effective,…

  7. Risk factors for ventilator-associated events: a case-control multivariable analysis.

    PubMed

    Lewis, Sarah C; Li, Lingling; Murphy, Michael V; Klompas, Michael

    2014-08-01

    The Centers for Disease Control and Prevention recently released new surveillance definitions for ventilator-associated events, including the new entities of ventilator-associated conditions and infection-related ventilator-associated complications. Both ventilator-associated conditions and infection-related ventilator-associated complications are associated with prolonged mechanical ventilation and hospital death, but little is known about their risk factors and how best to prevent them. We sought to identify risk factors for ventilator-associated conditions and infection-related ventilator-associated complications. Retrospective case-control study. Medical, surgical, cardiac, and neuroscience units of a tertiary care teaching hospital. Hundred ten patients with ventilator-associated conditions matched to 110 controls without ventilator-associated conditions on the basis of age, sex, ICU type, comorbidities, and duration of mechanical ventilation prior to ventilator-associated conditions. None. We compared cases with controls with regard to demographics, comorbidities, ventilator bundle adherence rates, sedative exposures, routes of nutrition, blood products, fluid balance, and modes of ventilatory support. We repeated the analysis for the subset of patients with infection-related ventilator-associated complications and their controls. Case and control patients were well matched on baseline characteristics. On multivariable logistic regression, significant risk factors for ventilator-associated conditions were mandatory modes of ventilation (odds ratio, 3.4; 95% CI, 1.6-8.0) and positive fluid balances (odds ratio, 1.2 per L positive; 95% CI, 1.0-1.4). Possible risk factors for infection-related ventilator-associated complications were starting benzodiazepines prior to intubation (odds ratio, 5.0; 95% CI, 1.3-29), total opioid exposures (odds ratio, 3.3 per 100 μg fentanyl equivalent/kg; 95% CI, 0.90-16), and paralytic medications (odds ratio, 2.3; 95% CI, 0

  8. Displaced Homemakers: Unresolved Issues.

    ERIC Educational Resources Information Center

    Zawada, Mary Ann

    1980-01-01

    Problems of today's displaced homemakers overlap with those of women in the 1960s. Problems of women seeking employment are similar to those of minority groups, older workers and welfare recipients. Recent legislation has expanded to fulfill some of the needs of women returning to the labor force. (Author/BEF)

  9. Single-mode displacement sensor

    NASA Astrophysics Data System (ADS)

    Duivenvoorden, Kasper; Terhal, Barbara M.; Weigand, Daniel

    2017-01-01

    We show that one can determine both parameters of a displacement acting on an oscillator with an accuracy which scales inversely with the square root of the number of photons in the oscillator. Our results are obtained by using a grid state as a sensor state for detecting small translations in phase space (displacements). Grid states were first proposed [D. Gottesman et al., Phys. Rev. A 64, 012310 (2001), 10.1103/PhysRevA.64.012310] for encoding a qubit into an oscillator: an efficient preparation protocol of such states, using a coupling to a qubit, was later developed [B. M. Terhal and D. Weigand, Phys. Rev. A 93, 012315 (2016), 10.1103/PhysRevA.93.012315]. We compare the performance of the grid state with the quantum compass or cat code state and place our results in the context of the two-parameter quantum Cramér-Rao lower bound on the variances of the displacement parameters. We show that the accessible information about the displacement for a grid state increases with the number of photons in the state when we measure and prepare the state using a phase estimation protocol. This is in contrast with the accessible information in the quantum compass state which we show is always upper bounded by a constant, independent of the number of photons. We present numerical simulations of a phase estimation based preparation protocol of a grid state in the presence of photon loss, nonlinearities, and qubit measurement, using no post-selection, showing how the two effective squeezing parameters which characterize the grid state change during the preparation. The idea behind the phase estimation protocol is a simple maximal-information gain strategy.

  10. Patient-ventilator dyssynchrony during assisted invasive mechanical ventilation.

    PubMed

    Murias, G; Villagra, A; Blanch, L

    2013-04-01

    Patient-ventilator dyssynchrony is common during mechanical ventilation. Dyssynchrony decreases comfort, prolongs mechanical ventilation and intensive care unit stays, and might lead to worse outcome. Dyssynchrony can occur during the triggering of the ventilator, the inspiration period after triggering, the transition from inspiration to expiration, and the expiratory phase. The most common dyssynchronies are delayed triggering, autotriggering, ineffective inspiratory efforts (which can occur at any point in the respiratory cycle), mismatch between the patient's and ventilator's inspiratory times, and double triggering. At present, the detection of dyssynchronies usually depends on healthcare staff observing ventilator waveforms; however, performance is suboptimal and many events go undetected. To date, technological complexity has made it impossible to evaluate patient-ventilator synchrony throughout the course of mechanical ventilation. Studies have shown that a high index of dyssynchrony may increase the duration of mechanical ventilation. Better training, better ventilatory modes, and/or computerized systems that permit better synchronization of patients' demands and ventilator outputs are necessary to improve patient-ventilator synchrony.

  11. Design Feature 7: Continuous Preclosure Ventilation

    SciTech Connect

    A.T. Watkins

    1999-06-22

    This design feature (DF) is intended to evaluate the effects of continuous ventilation in the emplacement drifts during preclosure and how the effects, if any, compare to the Viability Assessment (VA) reference design for postclosure long term performance. This DF will be evaluated against a set of criteria provided by the License Application Design Selection (LADS) group. The VA reference design included a continuous ventilation airflow quantity of 0.1 m{sup 3}/s in the emplacement drifts in the design of the repository subsurface facilities. The effects of this continuous ventilation during the preclosure was considered to have a negligible effect on postclosure performance and therefore is not included during postclosure in the assessment of the long term performance. This DF discusses the effects of continuous ventilation on the emplacement drift environment and surrounding rock conditions during preclosure for three increased airflow quantities. The three cases of continuous ventilation systems are: System A, 1.0 m{sup 3}/s (Section 8), System B, 5.0 m{sup 3}/s (Section 9), and System C, 10.0 m{sup 3}/s (Section 10) in each emplacement drift split. An emplacement drift split is half total length of emplacement drift going from the east or west main to the exhaust main. The difference in each system is the quantity of airflow in the emplacement drifts.

  12. Tunnel Ventilation Control Using Reinforcement Learning Methodology

    NASA Astrophysics Data System (ADS)

    Chu, Baeksuk; Kim, Dongnam; Hong, Daehie; Park, Jooyoung; Chung, Jin Taek; Kim, Tae-Hyung

    The main purpose of tunnel ventilation system is to maintain CO pollutant concentration and VI (visibility index) under an adequate level to provide drivers with comfortable and safe driving environment. Moreover, it is necessary to minimize power consumption used to operate ventilation system. To achieve the objectives, the control algorithm used in this research is reinforcement learning (RL) method. RL is a goal-directed learning of a mapping from situations to actions without relying on exemplary supervision or complete models of the environment. The goal of RL is to maximize a reward which is an evaluative feedback from the environment. In the process of constructing the reward of the tunnel ventilation system, two objectives listed above are included, that is, maintaining an adequate level of pollutants and minimizing power consumption. RL algorithm based on actor-critic architecture and gradient-following algorithm is adopted to the tunnel ventilation system. The simulations results performed with real data collected from existing tunnel ventilation system and real experimental verification are provided in this paper. It is confirmed that with the suggested controller, the pollutant level inside the tunnel was well maintained under allowable limit and the performance of energy consumption was improved compared to conventional control scheme.

  13. Computational fluid dynamics in ventilation: Practical approach

    NASA Astrophysics Data System (ADS)

    Fontaine, J. R.

    The potential of computation fluid dynamics (CFD) for conceiving ventilation systems is shown through the simulation of five practical cases. The following examples are considered: capture of pollutants on a surface treating tank equipped with a unilateral suction slot in the presence of a disturbing air draft opposed to suction; dispersion of solid aerosols inside fume cupboards; performances comparison of two general ventilation systems in a silkscreen printing workshop; ventilation of a large open painting area; and oil fog removal inside a mechanical engineering workshop. Whereas the two first problems are analyzed through two dimensional numerical simulations, the three other cases require three dimensional modeling. For the surface treating tank case, numerical results are compared to laboratory experiment data. All simulations are carried out using EOL, a CFD software specially devised to deal with air quality problems in industrial ventilated premises. It contains many analysis tools to interpret the results in terms familiar to the industrial hygienist. Much experimental work has been engaged to validate the predictions of EOL for ventilation flows.

  14. Permeability of displaced fractures

    NASA Astrophysics Data System (ADS)

    Kluge, Christian; Milsch, Harald; Blöcher, Guido

    2017-04-01

    Flow along fractures or in fissured systems becomes increasingly important in the context of Enhanced Geothermal Systems (EGS), shale gas recovery or nuclear waste deposit. Commonly, the permeability of fractures is approximated using the Hagen-Poiseuille solution of Navier Stokes equation. Furthermore, the flow in fractures is assumed to be laminar flow between two parallel plates and the cubic law for calculating the velocity field is applied. It is a well-known fact, that fracture flow is strongly influenced by the fracture surface roughness and the shear displacement along the fracture plane. Therefore, a numerical approach was developed which calculates the flow pattern within a fracture-matrix system. The flow in the fracture is described by a free fluid flow and the flow in the matrix is assumed to be laminar and therefore validates Darcy's law. The presented approach can be applied for artificially generated fractures or real fractures measured by surface scanning. Artificial fracture surfaces are generated using the power spectral density of the surface height random process with a spectral exponent to define roughness. For calculating the permeability of such fracture-matrix systems the mean fracture aperture, the shear displacement and the surface roughness are considered by use of a 3D numerical simulator. By use of this approach correlation between shear displacement and mean aperture, shear displacement and permeability, as well as surface roughness and permeability can be obtained. Furthermore, the intrinsic measured permeability presents a combination of matrix and fracture permeability. The presented approach allows the separation and quantification of the absolute magnitudes of the matrix and the fracture permeability and the permeability of displaced fractures can be calculated. The numerical approach which is a 3D numerical simulation of the fracture-matrix system can be applied for artificial as well as real systems.

  15. Football Equipment Removal Improves Chest Compression and Ventilation Efficacy.

    PubMed

    Mihalik, Jason P; Lynall, Robert C; Fraser, Melissa A; Decoster, Laura C; De Maio, Valerie J; Patel, Amar P; Swartz, Erik E

    2016-01-01

    Airway access recommendations in potential catastrophic spine injury scenarios advocate for facemask removal, while keeping the helmet and shoulder pads in place for ensuing emergency transport. The anecdotal evidence to support these recommendations assumes that maintaining the helmet and shoulder pads assists inline cervical stabilization and that facial access guarantees adequate airway access. Our objective was to determine the effect of football equipment interference on performing chest compressions and delivering adequate ventilations on patient simulators. We hypothesized that conditions with more football equipment would decrease chest compression and ventilation efficacy. Thirty-two certified athletic trainers were block randomized to participate in six different compression conditions and six different ventilation conditions using human patient simulators. Data for chest compression (mean compression depth, compression rate, percentage of correctly released compressions, and percentage of adequate compressions) and ventilation (total ventilations, mean ventilation volume, and percentage of ventilations delivering adequate volume) conditions were analyzed across all conditions. The fully equipped athlete resulted in the lowest mean compression depth (F5,154 = 22.82; P < 0.001; Effect Size = 0.98) and delivery of adequate compressions (F5,154 = 15.06; P < 0.001; Effect Size = 1.09) compared to all other conditions. Bag-valve mask conditions resulted in delivery of significantly higher mean ventilation volumes compared to all 1- or 2-person pocketmask conditions (F5,150 = 40.05; P < 0.001; Effect Size = 1.47). Two-responder ventilation scenarios resulted in delivery of a greater number of total ventilations (F5,153 = 3.99; P = 0.002; Effect Size = 0.26) and percentage of adequate ventilations (F5,150 = 5.44; P < 0.001; Effect Size = 0.89) compared to one-responder scenarios. Non-chinstrap conditions permitted greater ventilation volumes (F3,28 = 35.17; P

  16. SU-E-J-90: Lobar-Level Lung Ventilation Analysis Using 4DCT and Deformable Image Registration

    SciTech Connect

    Du, K; Bayouth, J; Patton, T; Reinhardt, J; Gerard, S; Christensen, G; Zhao, B; Pan, Y

    2015-06-15

    Purpose: To assess regional changes in human lung ventilation and mechanics using four-dimensional computed tomography (4DCT) and deformable image registration. This work extends our prior analysis of the entire lung to a lobe-based analysis. Methods: 4DCT images acquired from 20 patients prior to radiation therapy (RT) were used for this analysis. Jacobian ventilation and motion maps were computed from the displacement field after deformable image registration between the end of expiration breathing phase and the end of inspiration breathing phase. The lobes were manually segmented on the reference phase by a medical physicist expert. The voxel-by-voxel ventilation and motion magnitude for all subjects were grouped by lobes and plotted into cumulative voxel frequency curves respectively. In addition, to eliminate the effect of different breathing efforts across subjects, we applied the inter-subject equivalent lung volume (ELV) method on a subset of the cohort and reevaluated the lobar ventilation. Results: 95% of voxels in the lung are expanding during inspiration. However, some local regions of lung tissue show far more expansion than others. The greatest expansion with respiration occurs within the lower lobes; between exhale and inhale the median expansion in lower lobes is approximately 15%, while the median expansion in upper lobes is 10%. This appears to be driven by a subset of lung tissues within the lobe that have greater expansion; twice the number of voxels in the lower lobes (20%) expand by > 30% when compared to the upper lobes (10%). Conclusion: Lung ventilation and motion show significant difference on the lobar level. There are different lobar fractions of driving voxels that contribute to the major expansion of the lung. This work was supported by NIH grant CA166703.

  17. Dependence of ventilation image derived from 4D CT on deformable image registration and ventilation algorithms.

    PubMed

    Latifi, Kujtim; Forster, Kenneth M; Hoffe, Sarah E; Dilling, Thomas J; van Elmpt, Wouter; Dekker, Andre; Zhang, Geoffrey G

    2013-07-08

    Ventilation imaging using 4D CT is a convenient and low-cost functional imaging methodology which might be of value in radiotherapy treatment planning to spare functional lung volumes. Deformable image registration (DIR) is needed to calculate ventilation imaging from 4D CT. This study investigates the dependence of calculated ventilation on DIR methods and ventilation algorithms. DIR of the normal end expiration and normal end inspiration phases of the 4D CT images was used to correlate the voxels between the two respiratory phases. Three different DIR algorithms, optical flow (OF), diffeomorphic demons (DD), and diffeomorphic morphons (DM) were retrospectively applied to ten esophagus and ten lung cancer cases with 4D CT image sets that encompassed the entire lung volume. The three ventilation extraction methods were used based on either the Jacobian, the change in volume of the voxel, or directly calculated from Hounsfield units. The ventilation calculation algorithms used are the Jacobian, ΔV, and HU method. They were compared using the Dice similarity coefficient (DSC) index and Bland-Altman plots. Dependence of ventilation images on the DIR was greater for the ΔV and the Jacobian methods than for the HU method. The DSC index for 20% of low-ventilation volume for ΔV was 0.33 ± 0.03 (1 SD) between OF and DM, 0.44 ± 0.05 between OF and DD, and 0.51 ± 0.04 between DM and DD. The similarity comparisons for Jacobian were 0.32 ± 0.03, 0.44 ± 0.05, and 0.51 ± 0.04, respectively, and for HU they were 0.53 ± 0.03, 0.56 ± 0.03, and 0.76 ± 0.04, respectively. Dependence of extracted ventilation on the ventilation algorithm used showed good agreement between the ΔV and Jacobian methods, but differed significantly for the HU method. DSC index for using OF as DIR was 0.86 ± 0.01 between ΔV and Jacobian, 0.28 ± 0.04 between ΔV and HU, and 0.28 ± 0.04 between Jacobian and HU, respectively. When using DM or DD as DIR, similar values were obtained when

  18. ASHRAE and residential ventilation

    SciTech Connect

    Sherman, Max H.

    2003-10-01

    In the last quarter of a century, the western world has become increasingly aware of environmental threats to health and safety. During this period, people psychologically retreated away from outdoors hazards such as pesticides, smog, lead, oil spills, and dioxin to the seeming security of their homes. However, the indoor environment may not be healthier than the outdoor environment, as has become more apparent over the past few years with issues such as mold, formaldehyde, and sick-building syndrome. While the built human environment has changed substantially over the past 10,000 years, human biology has not; poor indoor air quality creates health risks and can be uncomfortable. The human race has found, over time, that it is essential to manage the indoor environments of their homes. ASHRAE has long been in the business of ventilation, but most of the focus of that effort has been in the area of commercial and institutional buildings. Residential ventilation was traditionally not a major concern because it was felt that, between operable windows and envelope leakage, people were getting enough outside air in their homes. In the quarter of a century since the first oil shock, houses have gotten much more energy efficient. At the same time, the kinds of materials and functions in houses changed in character in response to people's needs. People became more environmentally conscious and aware not only about the resources they were consuming but about the environment in which they lived. All of these factors contributed to an increasing level of public concern about residential indoor air quality and ventilation. Where once there was an easy feeling about the residential indoor environment, there is now a desire to define levels of acceptability and performance. Many institutions--both public and private--have interests in Indoor Air Quality (IAQ), but ASHRAE, as the professional society that has had ventilation as part of its mission for over 100 years, is the

  19. A comparative study of teaching clinical guideline for prevention of ventilator-associated pneumonia in two ways: face-to-face and workshop training on the knowledge and practice of nurses in the intensive care unit.

    PubMed

    Yazdani, Majid; Sabetian, Golnar; Ra'ofi, Shahin; Roudgari, Amir; Feizi, Monireh

    2015-04-01

    Ventilator-associated pneumonia (VAP) is one of the most popular nosocomial infections in the intensive care units and the nurse's role in preventing it is very important. The aim of this study was to compare the effect of two methods of face to face training and work- shop clinical guidelines in prevention of VAP. In this experimental randomized clinical trial, the knowledge and practice of nurses in ICUs were studied in two groups: face to face training (35 nurses) and workshops (40 nurses) by using clinical guidelines in prevention of VAP in one of the hospitals of Shiraz University of Medical Sciences. The level of knowledge and practice in each group was assessed by self-report questionnaire, knowledge questionnaire and also direct observation of practice, before and after training. Data were analyzed with descriptive statistics, paired t-test, independent t-test, McNemar test, Fisher's exact, sign and Chi-square test, using SPSS 14. This study demonstrated that both methods of face to face training and workshop were very effective. The incidence of inappropriate pressure of cuff in the tracheal tubes and tracheostomy tubes was significantly reduced after training (p=0.001). But, by comparison of these two methods and the relationship between the variables revealed that no significant difference was found between the two groups of face to face training and workshop. Training the nurses is highly effective in preventing VAP, particularly for appropriate cuff pressure, suctioning and disinfecting hands.

  20. Tunable beam displacer

    SciTech Connect

    Salazar-Serrano, Luis José; Valencia, Alejandra; Torres, Juan P.

    2015-03-15

    We report the implementation of a tunable beam displacer, composed of a polarizing beam splitter (PBS) and two mirrors, that divides an initially polarized beam into two parallel beams whose separation can be continuously tuned. The two output beams are linearly polarized with either vertical or horizontal polarization and no optical path difference is introduced between them. The wavelength dependence of the device as well as the maximum separation between the beams achievable is limited mainly by the PBS characteristics.

  1. The photoelectric displacement converter

    NASA Astrophysics Data System (ADS)

    Dragoner, Valeriu V.

    2005-02-01

    In the article are examined questions of constructing photoelectric displacement converter satisfying demands that are stated above. Converter has channels of approximate and precise readings. The approximate reading may be accomplished either by the method of reading from a code mask or by the method of the consecutive calculation of optical scale gaps number. Phase interpolator of mouar strips" gaps is determined as a precise measuring. It is shown mathematical model of converter that allow evaluating errors and operating speed of conversion.

  2. RTV 21 Displacements

    SciTech Connect

    Kurita, C.H.; /Fermilab

    1987-02-04

    A seal is needed for the cover of the Nitrogen Test Vessel in order to prevent leakage of the N{sub 2} gas. This seal is to be molded out of RTV 21. In this experiment, the Modulus of Elasticity of the RTV was sought after, and the displacements of the RTV due to various stresses were measured to see if they were large enough to provide a tight seal between the vessel and its cover.

  3. Higher clinical success in patients with ventilator-associated pneumonia due to methicillin-resistant Staphylococcus aureus treated with linezolid compared with vancomycin: results from the IMPACT-HAP study

    PubMed Central

    2014-01-01

    Introduction Controversy exists regarding optimal treatment for ventilator-associated pneumonia (VAP) due to methicillin-resistant Staphylococcus aureus (MRSA). The primary objective of this study was to compare clinical success of linezolid versus vancomycin for the treatment of patients with MRSA VAP. Methods This was a multicenter, retrospective, observational study of patients with VAP (defined according to Centers for Disease Control and Prevention criteria) due to MRSA who were treated with linezolid or vancomycin. MRSA VAP was considered when MRSA was isolated from a tracheal aspirate or bronchoalveolar lavage. Clinical success was evaluated by assessing improvement or resolution of signs and symptoms of VAP by day 14. After matching on confounding factors, logistic regression models were used to determine if an association existed between treatment arm and clinical success. Results A total of 188 patients were evaluated (101 treated with linezolid and 87 with vancomycin). The mean ± standard deviation Acute Physiology and Chronic Health Evaluation (APACHE) II score was 21 ± 11 for linezolid- and 19 ± 9 for vancomycin-treated patients (P = 0.041). Clinical success occurred in 85% of linezolid-treated patients compared with 69% of vancomycin-treated patients (P = 0.009). After adjusting for confounding factors, linezolid-treated patients were 24% more likely to experience clinical success than vancomycin-treated patients (P = 0.018). Conclusions This study adds to the evidence indicating that patients with MRSA VAP who are treated with linezolid are more likely to respond favorably compared with patients treated with vancomycin. PMID:24916853

  4. Variable displacement vane pump

    SciTech Connect

    Tschantz, J.S.; Bisson, B.J.

    1997-12-31

    What has been developed under this program is a pumping system which can vary the amount of fuel delivered according to engine needs, thereby reducing the temperature rise of the fuel to very low levels. This permits the elimination of the air/oil coolers and conserves the vital airflow through the fan. The variable displacement vane pump (VDVP) also permits a substantial simplification of the control system with the elimination of complex metering valves, offering a significant reduction in fuel system cost. This program was initiated to develop a technology that embodied the ruggedness of the gear pump with the efficiency and metering versatility of the variable displacement vane pump. Thick metal vanes emulate the teeth on pumping gears while the simple, elegant swing cam feature provides the variable displacement capability without the unwieldy multiple cam segments found in other concepts. The result is a pumping architecture which is rugged, light in weight and extremely versatile, having demonstrated superb heat management and controllability in extensive bench and engine testing. This paper will report the results that the pumps have achieved to date both in terms of durability and efficiency.

  5. Ventilator-associated pneumonia.

    PubMed

    2009-11-01

    Ventilator-associated pneumonia is a pneumonia that develops initially more than 48 h from the start of tracheal intubation and mechanical ventilation. The route of infection is almost always through the respiratory tract. Intake of contaminants from outside the tracheal tube (silent aspiration) is considered a key route, and suctioning of secretions that have accumulated above the cuff of the endotracheal tubes is effective in preventing infection. The circuit is managed and heated-wire humidifiers and suction are manipulated based on appropriate infection control measures. To diagnose pathogens, efforts should be made to collect specimens from the pneumonia focus. Realistically, however, diagnosis can also be achieved based on the clinical course and from the results of culture of samples from tracheal aspirate. Use of prophylactic antimicrobials is not recommended, but once a diagnosis is made, antimicrobials are administered that combat the causative microorganism.

  6. Dynamic Behaviour of Ventilated Hydrofoils.

    NASA Astrophysics Data System (ADS)

    Kjeldsen, Morten; Arndt, Roger; Wosnik, Martin

    2006-11-01

    In certain types of pumping applications oscillations are induced by operation with liquids containing a free gas load. In order to understand the physics of this process, a series of tests with a ventilated A 2D NACA 0015 hydrofoil were performed in the water tunnel at the St. Anthony Falls Laboratory of the University of Minnesota. The special bubble removal feature of the water tunnel allowed continuous ventilation without experiencing visible bubbles upstream the hydrofoil. These studies build on previous work on cavitation-induced oscillations. Gas injection studies were made over a range of gas flow rates and test section pressure. The results clearly show that lift oscillations increase in intensity when the gas load is increased. The point of maximum unsteadiness is also associated the rapid decline of the foil performance as measured as average lift. Further increase of the gas injection load gives a steady behaviour with almost no lift. These experiments are compared with traditional cavitation experiments. The similarities between gas injection- and cavitation induced unsteadiness on the hydrofoil are many, but the amplitude of lift oscillations found on the foil with gas injection corresponds to about 50% of that found for cavitating hydrofoils. The fact that the oscillations are periodic leads to the consideration of both passive and active control.

  7. [Non-invasive ventilation].

    PubMed

    Gallardo Romero, Jose Manuel; García, Teresa Gómez; Sancho Chust, José Norberto; González Martínez, Mónica

    2010-10-01

    The advent of non-invasive mechanical ventilation (NIMV) has radically changed the management of acute and chronic respiratory failure. Over the last few years, the number of possible applications of NIMV has progressively increased, both in the hospital and extrahospital setting. NIMV is now used in all hospitals and resident physicians currently receive specific training -nonexistent until a few years ago- in this modality. It falls to all of us to push forward the clinical and scientific advances represented by the development of NIMV, by promoting the events that accompany better knowledge of the physiopathological bases of ventilation and of its continuous applications in daily clinical practice and by perfecting the elements required for the correct application of this technique. The present review aims to provide a broad overview of NIMV, from the most theoretical knowledge (the physiopathology of NIMV) to the most practical skills (recognition of patient-ventilator asynchrony). Through this progression from the complex to the most basic, or from the basics to the most complex, depending on the perspective taken, we aim to provide deeper knowledge of the concepts required to understand the technical functioning of the ventilator, describing its distinct modes and parameters and the abilities that must be developed for the correct indication, use and monitoring of the technique. We provide a final reflection on other forms of respiratory support that can be offered to patients with ventilatory failure. Copyright © 2010 Sociedad Española de Neumología y Cirugía Torácica. Published by Elsevier Espana. All rights reserved.

  8. Oven ventilation system

    SciTech Connect

    Brewer, D.E.

    1987-02-17

    A ventilation system is described for venting an oven with external surfaces, the oven being located within an enclosed space, the system comprising: intake means for collecting air from the external environment of the enclosed space; means for forming a sheet of the air and passing the sheet across the external surfaces of the oven; and exhaust means for exhausting the sheet of the air to the external environment of the enclosed space after the air has been passed across the external surfaces.

  9. Harnessing natural ventilation benefits.

    PubMed

    O'Leary, John

    2013-04-01

    Making sure that a healthcare establishment has a good supply of clean fresh air is an important factor in keeping patients, staff, and visitors, free from the negative effects of CO2 and other contaminants. John O'Leary of Trend Controls, a major international supplier of building energy management solutions (BEMS), examines the growing use of natural ventilation, and the health, energy-saving, and financial benefits, that it offers.

  10. Synchronized mechanical ventilation for respiratory support in newborn infants.

    PubMed

    Greenough, Anne; Rossor, Thomas E; Sundaresan, Adesh; Murthy, Vadivelam; Milner, Anthony D

    2016-09-01

    During synchronised mechanical ventilation, positive airway pressure and spontaneous inspiration coincide. If synchronous ventilation is provoked, adequate gas exchange should be achieved at lower peak airway pressures, potentially reducing baro/volutrauma, air leak and bronchopulmonary dysplasia. Synchronous ventilation can potentially be achieved by manipulation of rate and inspiratory time during conventional ventilation and employment of patient-triggered ventilation. To compare the efficacy of:(i) synchronised mechanical ventilation, delivered as high-frequency positive pressure ventilation (HFPPV) or patient-triggered ventilation (assist control ventilation (ACV) and synchronous intermittent mandatory ventilation (SIMV)), with conventional ventilation or high-frequency oscillation (HFO);(ii) different types of triggered ventilation (ACV, SIMV, pressure-regulated volume control ventilation (PRVCV), SIMV with pressure support (PS) and pressure support ventilation (PSV)). We used the standard search strategy of the Cochrane Neonatal Review group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 5), MEDLINE via PubMed (1966 to June 5 2016), EMBASE (1980 to June 5 2016), and CINAHL (1982 to June 5 2016). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. Randomised or quasi-randomised clinical trials comparing synchronised ventilation delivered as HFPPV to CMV, or ACV/SIMV to CMV or HFO in neonates. Randomised trials comparing different triggered ventilation modes (ACV, SIMV, SIMV plus PS, PRVCV and PSV) in neonates. Data were collected regarding clinical outcomes including mortality, air leaks (pneumothorax or pulmonary interstitial emphysema (PIE)), severe intraventricular haemorrhage (grades 3 and 4), bronchopulmonary dysplasia (BPD) (oxygen dependency beyond 28 days), moderate/severe BPD (oxygen

  11. Synchronized mechanical ventilation for respiratory support in newborn infants.

    PubMed

    Greenough, Anne; Murthy, Vadivelam; Milner, Anthony D; Rossor, Thomas E; Sundaresan, Adesh

    2016-08-19

    During synchronised mechanical ventilation, positive airway pressure and spontaneous inspiration coincide. If synchronous ventilation is provoked, adequate gas exchange should be achieved at lower peak airway pressures, potentially reducing baro/volutrauma, air leak and bronchopulmonary dysplasia. Synchronous ventilation can potentially be achieved by manipulation of rate and inspiratory time during conventional ventilation and employment of patient-triggered ventilation. To compare the efficacy of:(i) synchronised mechanical ventilation, delivered as high-frequency positive pressure ventilation (HFPPV) or patient-triggered ventilation (assist control ventilation (ACV) and synchronous intermittent mandatory ventilation (SIMV)), with conventional ventilation or high-frequency oscillation (HFO);(ii) different types of triggered ventilation (ACV, SIMV, pressure-regulated volume control ventilation (PRVCV), SIMV with pressure support (PS) and pressure support ventilation (PSV)). We used the standard search strategy of the Cochrane Neonatal Review group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 5), MEDLINE via PubMed (1966 to June 5 2016), EMBASE (1980 to June 5 2016), and CINAHL (1982 to June 5 2016). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. Randomised or quasi-randomised clinical trials comparing synchronised ventilation delivered as HFPPV to CMV, or ACV/SIMV to CMV or HFO in neonates. Randomised trials comparing different triggered ventilation modes (ACV, SIMV, SIMV plus PS, PRVCV and PSV) in neonates. Data were collected regarding clinical outcomes including mortality, air leaks (pneumothorax or pulmonary interstitial emphysema (PIE)), severe intraventricular haemorrhage (grades 3 and 4), bronchopulmonary dysplasia (BPD) (oxygen dependency beyond 28 days), moderate/severe BPD (oxygen

  12. Thermoregulation and ventilation of termite mounds

    NASA Astrophysics Data System (ADS)

    Korb, Judith

    2003-05-01

    Some of the most sophisticated of all animal-built structures are the mounds of African termites of the subfamily Macrotermitinae, the fungus-growing termites. They have long been studied as fascinating textbook examples of thermoregulation or ventilation of animal buildings. However, little research has been designed to provide critical tests of these paradigms, derived from a very small number of original papers. Here I review results from recent studies on Macrotermes bellicosus that considered the interdependence of ambient temperature, thermoregulation, ventilation and mound architecture, and that question some of the fundamental paradigms of termite mounds. M. bellicosus achieves thermal homeostasis within the mound, but ambient temperature has an influence too. In colonies in comparably cool habitats, mound architecture is adapted to reduce the loss of metabolically produced heat to the environment. While this has no negative consequences in small colonies, it produces a trade-off with gas exchange in large colonies, resulting in suboptimally low nest temperatures and increased CO2 concentrations. Along with the alteration in mound architecture, the gas exchange/ventilation mechanism also changes. While mounds in the thermally appropriate savannah have a very efficient circular ventilation during the day, the ventilation in the cooler forest is a less efficient upward movement of air, with gas exchange restricted by reduced surface exchange area. These results, together with other recent findings, question entrenched ideas such as the thermosiphon-ventilation mechanism or the assumption that mounds function to dissipate internally produced heat. Models trying to explain the proximate mechanisms of mound building, or building elements, are discussed.

  13. Thermoregulation and ventilation of termite mounds.

    PubMed

    Korb, Judith

    2003-05-01

    Some of the most sophisticated of all animal-built structures are the mounds of African termites of the subfamily Macrotermitinae, the fungus-growing termites. They have long been studied as fascinating textbook examples of thermoregulation or ventilation of animal buildings. However, little research has been designed to provide critical tests of these paradigms, derived from a very small number of original papers. Here I review results from recent studies on Macrotermes bellicosus that considered the interdependence of ambient temperature, thermoregulation, ventilation and mound architecture, and that question some of the fundamental paradigms of termite mounds. M. bellicosus achieves thermal homeostasis within the mound, but ambient temperature has an influence too. In colonies in comparably cool habitats, mound architecture is adapted to reduce the loss of metabolically produced heat to the environment. While this has no negative consequences in small colonies, it produces a trade-off with gas exchange in large colonies, resulting in suboptimally low nest temperatures and increased CO(2) concentrations. Along with the alteration in mound architecture, the gas exchange/ventilation mechanism also changes. While mounds in the thermally appropriate savannah have a very efficient circular ventilation during the day, the ventilation in the cooler forest is a less efficient upward movement of air, with gas exchange restricted by reduced surface exchange area. These results, together with other recent findings, question entrenched ideas such as the thermosiphon-ventilation mechanism or the assumption that mounds function to dissipate internally produced heat. Models trying to explain the proximate mechanisms of mound building, or building elements, are discussed.

  14. Ventilation Systems Operating Experience Review for Fusion Applications

    SciTech Connect

    L. C. Cadwallader

    1999-12-01

    This report is a collection and review of system operation and failure experiences for air ventilation systems in nuclear facilities. These experiences are applicable for magnetic and inertial fusion facilities since air ventilation systems are support systems that can be considered generic to nuclear facilities. The report contains descriptions of ventilation system components, operating experiences with these systems, component failure rates, and component repair times. Since ventilation systems have a role in mitigating accident releases in nuclear facilities, these data are useful in safety analysis and risk assessment of public safety. An effort has also been given to identifying any safety issues with personnel operating or maintaining ventilation systems. Finally, the recommended failure data were compared to an independent data set to determine the accuracy of individual values. This comparison is useful for the International Energy Agency task on fusion component failure rate data collection.

  15. Automated quantitative analysis of ventilation-perfusion lung scintigrams

    SciTech Connect

    Burton, G.H.; Vernon, P.; Seed, W.A.

    1984-05-01

    An automated computer analysis of ventilation (Kr-81m) and perfusion (Tc-99m) lung images has been devised that produces a graphical image of the distribution of ventilation and perfusion, and of ventilation-perfusion ratios. The analysis has overcome the following problems: the identification of the midline between two lungs and the lung boundaries, the exclusion of extrapulmonary radioactivity, the superimposition of lung images of different sizes, and the format for presentation of the data. Therefore, lung images of different sizes and shapes may be compared with each other. The analysis has been used to develop normal ranges from 55 volunteers. Comparison of younger and older age groups of men and women show small but significant differences in the distribution of ventilation and perfusion, but no differences in ventilation-perfusion ratios.

  16. Home Mechanical Ventilation in Children.

    PubMed

    Preutthipan, Aroonwan

    2015-09-01

    The number of children dependent on home mechanical ventilation has been reported to be increasing in many countries around the world. Home mechanical ventilation has been well accepted as a standard treatment of children with chronic respiratory failure. Some children may need mechanical ventilation as a lifelong therapy. To send mechanically ventilated children back home may be more difficult than adults. However, relatively better outcomes have been demonstrated in children. Children could be safely ventilated at home if they are selected and managed properly. Conditions requiring home ventilation include increased respiratory load from airway or lung pathologies, ventilatory muscle weakness and failure of neurologic control of ventilation. Home mechanical ventilation should be considered when the patient develops progressive respiratory failure or intractable failure to wean mechanical ventilation. Polysomnography or overnight pulse oximetry plus capnometry are used to detect nocturnal hypoventilation in early stage of respiratory failure. Ventilator strategy including non-invasive and invasive approach should be individualized for each patient. The author strongly believes that parents and family members are able to take care of their child at home if they are trained and educated effectively. A good team work with dedicated members is the key factor of success.

  17. Diaphragmatic dysfunction in mechanical ventilation.

    PubMed

    Haitsma, Jack J

    2011-04-01

    It has become clear from experimental data that prolonged mechanical ventilation can induce diaphragm dysfunction, also known as ventilator-induced diaphragm dysfunction. In this article we will discuss most recent understanding on ventilator-induced diaphragm dysfunction and data on diaphragm dysfunction in patients. Over the last year several studies confirmed the existence of diaphragm dysfunction in patients. Known atrophy pathways are activated in patients undergoing prolonged conventional ventilation resulting in muscle proteolysis and a decrease in myofiber content. The loss of diaphragm force is time-dependent, but current data do not distinguish between the role played by other factors involved in diaphragm dysfunction. Diaphragm dysfunction occurs in patients, especially when ventilated with controlled modes of ventilation that minimize diaphragm activity. Time on the ventilator seems to be one of the biggest risk factors resulting in difficulties in weaning patients and prolonging time on the ventilator. Future trials should investigate whether improved patient-ventilator synchrony can reduce ventilator-induced diaphragm dysfunction and decrease weaning failure.

  18. Ventilators for noninvasive ventilation to treat acute respiratory failure.

    PubMed

    Scala, Raffaele; Naldi, Mario

    2008-08-01

    The application of noninvasive ventilation (NIV) to treat acute respiratory failure has increased tremendously both inside and outside the intensive care unit. The choice of ventilator is crucial for success of NIV in the acute setting, because poor tolerance and excessive air leaks are significantly correlated with NIV failure. Patient-ventilator asynchrony and discomfort can occur if the physician or respiratory therapist fails to adequately set NIV to respond to the patient's ventilatory demand, so clinicians need to fully understood the ventilator's technical peculiarities (eg, efficiency of trigger and cycle systems, speed of pressurization, air-leak compensation, CO(2) rebreathing, reliability of fraction of inspired oxygen reading, monitoring accuracy). A wide range of ventilators of different complexity have been introduced into clinical practice to noninvasively support patients in acute respiratory failure, but the numerous commercially available ventilators (bi-level, intermediate, and intensive care unit ventilators) have substantial differences that can influence patient comfort, patient-ventilator interaction, and, thus, the chance of NIV clinical success. This report examines the most relevant aspects of the historical evolution, the equipment, and the acute-respiratory-failure clinical application of NIV ventilators.

  19. Critical evaluation of emergency stockpile ventilators in an in vitro model of pediatric lung injury.

    PubMed

    Custer, Jason W; Watson, Christopher M; Dwyer, Joe; Kaczka, David W; Simon, Brett A; Easley, R Blaine

    2011-11-01

    Modern health care systems may be inadequately prepared for mass casualty respiratory failure requiring mechanical ventilation. Current health policy has focused on the "stockpiling" of emergency ventilators, though little is known about the performance of these ventilators under conditions of respiratory failure in adults and children. In this study, we seek to compare emergency ventilator performance characteristics using a test lung simulating pediatric lung injury. Evaluation of ventilator performance using a test lung. Laboratory. None. Six transport/emergency ventilators capable of adult/child application were chosen on the basis of manufacturer specifications, Autovent 3000, Eagle Univent 754, EPV 100, LP-10, LTV 1200, and Parapac 200D. Manufacturer specifications for each ventilator were reviewed and compared with known standards for alarms and functionality for surge capacity ventilators. The delivered tidal volume, gas flow characteristics, and airway pressure waveforms were evaluated in vitro using a mechanical test lung to model pediatric lung injury and integrated software. Test lung and flow meter recordings were analyzed over a range of ventilator settings. Of the six ventilators assessed, only two had the minimum recommended alarm capability. Four of the six ventilators tested were capable of being set to deliver a tidal volume of less than 200 mL. The delivered tidal volume for all ventilators was within 8% of the nominal setting at a positive end expiratory pressure of zero but was reduced significantly with the addition of positive end expiratory pressure (range, ±10% to 30%; p < .01). All ventilators tested performed comparably at higher set tidal volumes; however, only three of the ventilators tested delivered a tidal volume across the range of ventilator settings that was comparable to that of a standard intensive care unit ventilator. Multiple ventilators are available for the provision of ventilation to children with respiratory failure in

  20. Comparing InSAR observations of incremental fault growth in the 2005-2010 Dabbahu (Ethiopia) rifting episode with cumulative displacement-length measurements from high-resolution LiDAR

    NASA Astrophysics Data System (ADS)

    Hofmann, B.; Wright, T.; Paton, D. A.; Rowland, J. V.; Vye, C.

    2012-12-01

    out in October 2009 covering the central section of the Dabbahu segment. The resulting DEM covers 800 km2 with, on average, one return every 4 m{2}, but including areas with 1 return per 0.25 m2. The height accuracy of the DEM is ˜ 10 cm. We identify the slipped structures by calculating the gradient of the unwrapped deformation. Once the structures have been identified and roughly picked we apply our new algorithm to pick hanging and footwall cut-offs along the surface faults and extract their displacement-length profiles from the LiDAR. At the same time we automatically extract the incremental line-of-sight fault offsets from the InSAR data, converting these into vertical throw using an average sense of motion on the faults. By comparing these two measurements we can directly measure how faults are growing, and test models of fault growth and linkage. During each event we observe reactivation of faults along the entire length of the dike with several 10s of fault segments involved in each case. We can further see that the deformation is not just located along the obvious surface faults but that a considerable amount is located on buried structures.

  1. Proportional assist ventilation decreases thoracoabdominal asynchrony and chest wall distortion in preterm infants.

    PubMed

    Musante, G; Schulze, A; Gerhardt, T; Everett, R; Claure, N; Schaller, P; Bancalari, E

    2001-02-01

    Thoracoabdominal asynchrony (TAA) and chest wall distortion (CWD) are commonly seen in preterm infants secondary to a highly compliant rib cage and poor compensation of distorting forces by inspiratory rib cage muscles. Continuous positive airway pressure (CPAP) reduces TAA and CWD by stenting the chest wall. We hypothesized that application of positive airway pressure only during inspiration and in proportion to an infant's inspiratory effort should have a similar but more pronounced effect than CPAP alone. A ventilator providing airway pressure changes in proportion to flow and volume generated by an infant (proportional assist ventilation) was used to unload the respiratory pump during inspiration. Ten preterm infants were studied [birth weight, 745 (635-1175) g; gestational age, 26.5 (24-31) wk; postnatal age 3 (1-7) d; medium (range)]. TAA and CWD were determined by respiratory inductive plethysmography. TAA was expressed as the phase angle between the rib cage and abdominal motion and CWD as the total compartmental displacement ratio. In addition, we measured tidal volume with a pneumotachograph and esophageal and airway pressure deflections with pressure transducers. Measurements were obtained during alternating periods of CPAP and two different degrees of support (Gain 1 = 1.09 +/- 0.68, Gain 2 = 1.84 +/- 0.84 cm H(2)O/mL) that were provided by a proportional assist ventilator. Phase angle and the total compartmental displacement ratio decreased with increasing gain compared with CPAP alone. Peak airway pressure increased from 0.6 to 3.8 to 7.6 cm H(2)O above positive end-expiratory pressure (PEEP) with CPAP, Gain 1, and Gain 2, respectively, as tidal volume increased from 2.8 to 4.1 to 4.7 mL/kg. Esophageal pressure changes decreased only little with increasing gain. Chest wall excursion increased and abdominal movement decreased, indicating a redistribution of tidal volume between chest and abdomen. We conclude that proportional assist ventilation reduces

  2. Synthesis of finite displacements and displacements in continental margins

    NASA Technical Reports Server (NTRS)

    Speed, R. C.; Elison, M. W.; Heck, F. R.; Russo, R. M.

    1988-01-01

    The scope of the project is the analysis of displacement-rate fields in the transitional regions between cratonal and oceanic lithospheres over Phanerozoic time (last 700 ma). Associated goals are an improved understanding of range of widths of major displacement zones; the partition of displacement gradients and rotations with position and depth in such zones; the temporal characteristics of such zones-the steadiness, episodicity, and duration of uniform versus nonunifrom fields; and the mechanisms and controls of the establishment and kinematics of displacement zones. The objective is to provide a context of time-averaged kinematics of displacement zones. The initial phase is divided topically among the methodology of measurement and reduction of displacements in the lithosphere and the preliminary analysis from geologic and other data of actual displacement histories from the Cordillera, Appalachians, and southern North America.

  3. An electromechanical displacement transducer

    NASA Astrophysics Data System (ADS)

    Villiers, Marius; Mahboob, Imran; Nishiguchi, Katsuhiko; Hatanaka, Daiki; Fujiwara, Akira; Yamaguchi, Hiroshi

    2016-08-01

    Two modes of an electromechanical resonator are coupled through the strain inside the structure with a cooperativity as high as 107, a state-of-the-art value for purely mechanical systems, which enables the observation of normal-mode splitting. This coupling is exploited to transduce the resonator’s fundamental mode into the bandwidth of the second flexural mode, which is 1.4 MHz higher in frequency. Thus, an all-mechanical heterodyne detection scheme is implemented that can be developed into a high-precision displacement sensor.

  4. [Jet ventilation in laryngotracheal surgery].

    PubMed

    Friedrich, G; Mausser, G; Gugatschka, M

    2008-12-01

    Conventional endotracheal intubation can be a limiting factor in endolaryngeal and endotracheal surgery. Tubeless jet ventilation can overcome this problem and provides an unlimited operation field to the surgeon. Since the development of first jet ventilation systems, many modifications have been performed and are used permanently in daily clinical routine. The aim of this work is to provide an overview of widely used jet ventilation systems and furthermore to list all advantages, as well as disadvantages of this technique in laryngotracheal surgery.

  5. 46 CFR 111.105-21 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Ventilation. 111.105-21 Section 111.105-21 Shipping... REQUIREMENTS Hazardous Locations § 111.105-21 Ventilation. A ventilation duct which ventilates a hazardous location has the classification of that location. Each fan for ventilation of a hazardous location must...

  6. 46 CFR 111.105-21 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Ventilation. 111.105-21 Section 111.105-21 Shipping... REQUIREMENTS Hazardous Locations § 111.105-21 Ventilation. A ventilation duct which ventilates a hazardous location has the classification of that location. Each fan for ventilation of a hazardous location must...

  7. 46 CFR 111.105-21 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Ventilation. 111.105-21 Section 111.105-21 Shipping... REQUIREMENTS Hazardous Locations § 111.105-21 Ventilation. A ventilation duct which ventilates a hazardous location has the classification of that location. Each fan for ventilation of a hazardous location must...

  8. Pediatric Ventilator-Associated Infections: The Ventilator-Associated INfection Study.

    PubMed

    Willson, Douglas F; Hoot, Michelle; Khemani, Robinder; Carrol, Christopher; Kirby, Aileen; Schwarz, Adam; Gedeit, Rainer; Nett, Sholeen T; Erickson, Simon; Flori, Heidi; Hays, Spencer; Hall, Mark

    2017-01-01

    Suspected ventilator-associated infection is the most common reason for antibiotics in the PICU. We sought to characterize the clinical variables associated with continuing antibiotics after initial evaluation for suspected ventilator-associated infection and to determine whether clinical variables or antibiotic treatment influenced outcomes. Prospective, observational cohort study conducted in 47 PICUs in the United States, Canada, and Australia. Two hundred twenty-nine pediatric patients ventilated more than 48 hours undergoing respiratory secretion cultures were enrolled as "suspected ventilator-associated infection" in a prospective cohort study, those receiving antibiotics of less than or equal to 3 days were categorized as "evaluation only," and greater than 3 days as "treated." Demographics, diagnoses, comorbidities, culture results, and clinical data were compared between evaluation only and treated subjects and between subjects with positive versus negative cultures. PICUs in 47 hospitals in the United States, Canada, and Australia. All patients undergoing respiratory secretion cultures during the 6 study periods. None. Treated subjects differed from evaluation-only subjects only in frequency of positive cultures (79% vs 36%; p < 0.0001). Subjects with positive cultures were more likely to have chronic lung disease, tracheostomy, and shorter PICU stay, but there were no differences in ventilator days or mortality. Outcomes were similar in subjects with positive or negative cultures irrespective of antibiotic treatment. Immunocompromise and higher Pediatric Logistic Organ Dysfunction scores were the only variables associated with mortality in the overall population, but treated subjects with endotracheal tubes had significantly lower mortality. Positive respiratory cultures were the primary determinant of continued antibiotic treatment in children with suspected ventilator-associated infection. Positive cultures were not associated with worse outcomes

  9. Face mask ventilation: a comparison of three techniques.

    PubMed

    Hart, Danielle; Reardon, Robert; Ward, Christopher; Miner, James

    2013-05-01

    There are multiple techniques for face-mask (FM) ventilation. To our knowledge, the one-handed vs. two-handed C-E technique has been compared in children and adults, but no studies have compared the various two-handed methods. To compare the effectiveness of mask seal using three different FM techniques on a model intended to simulate difficult FM ventilation and measure ventilation performance. This was a prospective randomized study of health care providers. A standard airway-training mannequin was modified to produce variable airway resistance and allow measurements of ventilation volume and pressure. Each subject performed FM ventilation for 3 min per technique (30 breaths) in a randomized order. Median exhaled tidal volume and proximal peak flow pressure were determined and compared. Seventy subjects were enrolled. Both two-handed ventilation techniques were more effective than the one-handed technique by both volume and pressure measurements. The one-handed C-E technique yielded a median volume of 428.4 mL, vs. the two-handed C-E technique with 550.8 mL, and the two-handed V-E technique with 538 mL (p < 0.001). Peak pressure measurements revealed a median of 54.6 cm H2O for the one-handed C-E technique, 66 cm H2O for the two-handed C-E technique, and 66.6 cm H2O for the two-handed V-E technique (p < 0.001). There was not a difference between the various two-handed techniques. This model for FM ventilation is able to differentiate the efficacy of FM techniques. Both two-handed ventilation methods were superior to one-handed ventilation, both of which should perhaps be included in airway training for health care providers. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Field measurement of ventilation rates.

    PubMed

    Persily, A K

    2016-02-01

    Ventilation rates have significant impacts on building energy use and indoor contaminant concentrations, making them key parameters in building performance. Ventilation rates have been measured in buildings for many decades, and there are mature measurement approaches available to researchers and others who need to know actual ventilation rates in buildings. Despite the fact that ventilation rates are critical in interpreting indoor concentration measurements, it is disconcerting how few Indoor Air Quality field studies measure ventilation rates or otherwise characterize the ventilation design of the study building(s). This paper summarizes parameters of interest in characterizing building ventilation, available methods for quantifying these parameters, and challenges in applying these methods to different types of buildings and ventilation systems. These parameters include whole-building air change rates, system outdoor air intake rates, and building infiltration rates. Tracer gas methods are reviewed as well as system airflow rate measurements using, for example, duct traverses. Several field studies of ventilation rates conducted over the past 75 years are described to highlight the approaches employed and the findings obtained.

  11. 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

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

    PubMed

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

    2017-03-01

    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. 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. Noninvasive ventilation versus invasive mechanical ventilation. 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). 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

  13. Displaced patella fractures.

    PubMed

    Della Rocca, Gregory J

    2013-10-01

    Displaced patella fractures often result in disruption of the extensor mechanism of the knee. An intact extensor mechanism is a requirement for unassisted gait. Therefore, operative treatment of the displaced patella fracture is generally recommended. The evaluation of the patella fracture patient includes examination of extensor mechanism integrity. Operative management of patella fractures normally includes open reduction with internal fixation, although partial patellectomy is occasionally performed, with advancement of quadriceps tendon or patellar ligament to the fracture bed. Open reduction with internal fixation has historically been performed utilizing anterior tension band wiring, although comminution of the fracture occasionally makes this fixation construct inadequate. Supplementation or replacement of the tension band wire construct with interfragmentary screws, cerclage wire or suture, and/or plate-and-screw constructs may add to the stability of the fixation construct. Arthrosis of the patellofemoral joint is very common after healing of patella fractures, and substantial functional deficits may persist long after fracture healing has occurred. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  14. Lung Motion Model Validation Experiments, Free-Breathing Tissue Densitometry, and Ventilation Mapping using Fast Helical CT Imaging

    NASA Astrophysics Data System (ADS)

    Dou, Hsiang-Tai

    The uncertainties due to respiratory motion present significant challenges to accurate characterization of cancerous tissues both in terms of imaging and treatment. Currently available clinical lung imaging techniques are subject to inferior image quality and incorrect motion estimation, with consequences that can systematically impact the downstream treatment delivery and outcome. The main objective of this thesis is the development of the techniques of fast helical computed tomography (CT) imaging and deformable image registration for the radiotherapy applications in accurate breathing motion modeling, lung tissue density modeling and ventilation imaging. Fast helical CT scanning was performed on 64-slice CT scanner using the shortest available gantry rotation time and largest pitch value such that scanning of the thorax region amounts to just two seconds, which is less than typical breathing cycle in humans. The scanning was conducted under free breathing condition. Any portion of the lung anatomy undergoing such scanning protocol would be irradiated for only a quarter second, effectively removing any motion induced image artifacts. The resulting CT data were pristine volumetric images that record the lung tissue position and density in a fraction of the breathing cycle. Following our developed protocol, multiple fast helical CT scans were acquired to sample the tissue positions in different breathing states. To measure the tissue displacement, deformable image registration was performed that registers the non-reference images to the reference one. In modeling breathing motion, external breathing surrogate signal was recorded synchronously with the CT image slices. This allowed for the tissue-specific displacement to be modeled as parametrization of the recorded breathing signal using the 5D lung motion model. To assess the accuracy of the motion model in describing tissue position change, the model was used to simulate the original high-pitch helical CT scan

  15. Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    SciTech Connect

    Rudd, A.; Bergey, D.

    2014-02-01

    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. 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. It was inferior because the source of outside air was not direct from outside, the ventilation air was not distributed, and no provision existed for air 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, and 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.

  16. Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    SciTech Connect

    Rudd, Armin; Bergey, Daniel

    2014-02-01

    In this project, Building America research team Building Science Corporation tested the effectiveness of ventilation systems 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. 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. This was because the source of outside air was not direct from outside, the ventilation air was not distributed, and no provision existed for air 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, and 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.

  17. Ventilation heterogeneity in obesity.

    PubMed

    Pellegrino, Riccardo; Gobbi, Alessandro; Antonelli, Andrea; Torchio, Roberto; Gulotta, Carlo; Pellegrino, Giulia Michela; Dellacà, Raffaele; Hyatt, Robert E; Brusasco, Vito

    2014-05-01

    Obesity is associated with important decrements in lung volumes. Despite this, ventilation remains normally or near normally distributed at least for moderate decrements in functional residual capacity (FRC). We tested the hypothesis that this is because maximum flow increases presumably as a result of an increased lung elastic recoil. Forced expiratory flows corrected for thoracic gas compression volume, lung volumes, and forced oscillation technique at 5-11-19 Hz were measured in 133 healthy subjects with a body mass index (BMI) ranging from 18 to 50 kg/m(2). Short-term temporal variability of ventilation heterogeneity was estimated from the interquartile range of the frequency distribution of the difference in inspiratory resistance between 5 and 19 Hz (R5-19_IQR). FRC % predicted negatively correlated with BMI (r = -0.72, P < 0.001) and with an increase in slope of either maximal (r = -0.34, P < 0.01) or partial flow-volume curves (r = -0.30, P < 0.01). Together with a slight decrease in residual volume, this suggests an increased lung elastic recoil. Regression analysis of R5-19_IQR against FRC % predicted and expiratory reserve volume (ERV) yielded significantly higher correlation coefficients by nonlinear than linear fitting models (r(2) = 0.40 vs. 0.30 for FRC % predicted and r(2) = 0.28 vs. 0.19 for ERV). In conclusion, temporal variability of ventilation heterogeneities increases in obesity only when FRC falls approximately below 65% of predicted or ERV below 0.6 liters. Above these thresholds distribution is quite well preserved presumably as a result of an increase in lung recoil.

  18. Ventilated Oscillatory Boundary Layers

    DTIC Science & Technology

    1993-02-01

    AD-A266 226IllII !i III ll11111 II •" Ventilated Oscillatory Boundary Layers 0 Daniel -. Conley Douglas L. I nman C 0 UM U U U U till 1% w 1% W" Z t...A SIGNIFICANT NUMBER OF PAGES WHICH DO NOT REPRODUCE LEGIBLY. VENlTILATiD SCIILLAORY BOUNDARY LAYERS Daniel C. C7onley DoL’laN L. . ... La olDla...Wave Crest ........ 5. Boundary Layer Development Under the Wave Trough W 6 . Laboratory Observations .................. ................ 7

  19. Laboratory and Industrial Ventilation

    NASA Technical Reports Server (NTRS)

    1972-01-01

    This handbook supplements the Facilities Engineering Handbook (NHB 7320.1) and provides additional policies and criteria for uniform application to ventilation systems. It expands basic requirements, provides additional design and construction guidance, and places emphasis on those design considerations which will provide for greater effectiveness in the use of these systems. The provisions of this handbook are applicable to all NASA field installations and the Jet Propulsion Laboratory. Since supply of this handbook is limited, abstracts of the portion or portions applicable to a given requirement will be made for the individual specific needs encountered rather than supplying copies of the handbook as has been past practice.

  20. Comparison of respiratory and hemodynamic stability in patients with traumatic brain injury ventilated by two ventilator modes: Pressure regulated volume control versus synchronized intermittent mechanical ventilation

    PubMed Central

    Aghadavoudi, Omid; Alikiaii, Babak; Sadeghi, Fariba

    2016-01-01

    Background: This study aimed to compare pressure regulated volume control (PRVC) and synchronized intermittent mechanical ventilation (SIMV) modes of ventilation according to respiratory and hemodynamic stability in patients with traumatic brain injury (TBI) admitted to Intensive Care Unit (ICU). Materials and Methods: In a randomized, single-blinded, clinical trial study, 100 patients who hospitalized in ICU due to TBI were selected and randomly divided into two groups. The first and second groups were ventilated by PRVC and SIMV modes, respectively. During mechanical ventilation, arterial blood gas and respiratory and hemodynamic parameters were also recorded and compared between the two groups. Results: According to the t-test, the mean rapid shallow breathing index (RSBI) after the first 8 h of mechanical ventilation was significantly higher in SIMV group compared with PRVC group (107.6 ± 2.75 vs. 102.2 ± 5.2, respectively, P < 0.0001). Further, according to ANOVA with repeated measures, the trend of RSBI changes had a significant difference between the two groups (P < 0.001). The trend of ratio of partial pressure arterial oxygen and fraction of inspired oxygen was different between the two groups according to Mann–Whitney–Wilcoxon test (P < 0.001). Conclusions: Using PRVC mode might be more desirable than using SIMV mode in patients with TBI due to better stability of ventilation and oxygenating. To ensure for more advantages of PRVC mode, further studies with longer follow-up and more detailed measurements are recommended. PMID:28028515

  1. Radioaerosol ventilation imaging in ventilator-dependent patients. Technical considerations

    SciTech Connect

    Vezina, W.; Chamberlain, M.; Vinitski, S.; King, M.; Nicholson, R.; Morgan, W.K.

    1985-11-01

    The differentiation of pulmonary embolism (PE) from regional ventilatory abnormalities accompanied by reduced perfusion requires contemporary perfusion and ventilation studies. Distinguishing these conditions in ventilator-dependent patients is aided by administering a Tc-99m aerosol to characterize regional ventilation, and by performing a conventional Tc-99m MAA perfusion study. The technique uses a simple in-house constructed apparatus. Simple photographic techniques suffice, but computer subtraction of perfusion from the combined perfusion-ventilation image renders interpretation easier if aerosol administration follows perfusion imaging. Multiple defects can be examined in a single study. Excluding normal or near-normal perfusion studies, PE was thought to be present in eight of 16 patients after perfusion imaging alone, but in only one of eight after added aerosol imaging. Angiography confirmed the diagnosis in that patient. Of the eight patients who had abnormal perfusion but were thought unlikely to have PE from the perfusion study alone, two had normal ventilation, and subsequently were shown to have PE by angiography. Because angiography was only performed on patients who were thought to have a high probability of PE on sequential perfusion-ventilation imaging, the true incidence of PE may have been higher. Aerosol ventilation imaging is a useful adjunct to perfusion imaging in patients on ventilators. It requires an efficient delivery system, particularly if aerosol administration follows perfusion imaging, as it does in this study.

  2. Modeling ventilation time in forage tower silos.

    PubMed

    Bahloul, A; Chavez, M; Reggio, M; Roberge, B; Goyer, N

    2012-10-01

    The fermentation process in forage tower silos produces a significant amount of gases, which can easily reach dangerous concentrations and constitute a hazard for silo operators. To maintain a non-toxic environment, silo ventilation is applied. Literature reviews show that the fermentation gases reach high concentrations in the headspace of a silo and flow down the silo from the chute door to the feed room. In this article, a detailed parametric analysis of forced ventilation scenarios built via numerical simulation was performed. The methodology is based on the solution of the Navier-Stokes equations, coupled with transport equations for the gas concentrations. Validation was achieved by comparing the numerical results with experimental data obtained from a scale model silo using the tracer gas testing method for O2 and CO2 concentrations. Good agreement was found between the experimental and numerical results. The set of numerical simulations made it possible to establish a simple analytical model to predict the minimum time required to ventilate a silo to make it safe to enter. This ventilation time takes into account the headspace above the forage, the airflow rate, and the initial concentrations of O2 and CO2. The final analytical model was validated with available results from the literature.

  3. Modeling particle loss in ventilation ducts

    SciTech Connect

    Sippola, Mark R.; Nazaroff, William W.

    2003-04-01

    Empirical equations were developed and applied to predict losses of 0.01-100 {micro}m airborne particles making a single pass through 120 different ventilation duct runs typical of those found in mid-sized office buildings. For all duct runs, losses were negligible for submicron particles and nearly complete for particles larger than 50 {micro}m. The 50th percentile cut-point diameters were 15 {micro}m in supply runs and 25 {micro}m in return runs. Losses in supply duct runs were higher than in return duct runs, mostly because internal insulation was present in portions of supply duct runs, but absent from return duct runs. Single-pass equations for particle loss in duct runs were combined with models for predicting ventilation system filtration efficiency and particle deposition to indoor surfaces to evaluate the fates of particles of indoor and outdoor origin in an archetypal mechanically ventilated building. Results suggest that duct losses are a minor influence for determining indoor concentrations for most particle sizes. Losses in ducts were of a comparable magnitude to indoor surface losses for most particle sizes. For outdoor air drawn into an unfiltered ventilation system, most particles smaller than 1 {micro}m are exhausted from the building. Large particles deposit within the building, mostly in supply ducts or on indoor surfaces. When filters are present, most particles are either filtered or exhausted. The fates of particles generated indoors follow similar trends as outdoor particles drawn into the building.

  4. [Percutaneous tracheostomy in the ventilated patient].

    PubMed

    Añón, J M; Araujo, J B; Escuela, M P; González-Higueras, E

    2014-04-01

    The medical indications of tracheostomy comprise the alleviation of upper airway obstruction; the prevention of laryngeal and upper airway damage due to prolonged translaryngeal intubation in patients subjected to prolonged mechanical ventilation; and the facilitation of airway access for the removal of secretions. Since 1985, percutaneous tracheostomy (PT) has gained widespread acceptance as a method for creating a surgical airway in patients requiring long-term mechanical ventilation. Since then, several comparative trials of PT and surgical tracheostomy have been conducted, and new techniques for PT have been developed. The use of percutaneous dilatation techniques under bronchoscopic control are now increasingly popular throughout the world. Tracheostomy should be performed as soon as the need for prolonged intubation is identified. However a validated model for the prediction of prolonged mechanical ventilation is not available, and the timing of tracheostomy should be individualized. The present review analyzes the state of the art of PT in mechanically ventilated patients--this being regarded by many as the technique of choice in performing tracheostomy in critically ill patients. Copyright © 2012 Elsevier España, S.L. and SEMICYUC. All rights reserved.

  5. The use of mechanical ventilation in the ED.

    PubMed

    Easter, Benjamin D; Fischer, Christopher; Fisher, Jonathan

    2012-09-01

    Although EDs are responsible for the initial care of critically ill patients and the amount of critical care provided in the ED is increasing, there are few data examining mechanical ventilation (MV) in the ED. In addition, characteristics of ED-based ventilation may affect planning for ventilator shortages during pandemic influenza or bioterrorist events. The study examined the epidemiology of MV in US EDs, including demographic, clinical, and hospital characteristics; indications for MV; ED length of stay (LOS); and in-hospital mortality. This study was a retrospective review of the 1993 to 2007 National Hospital Ambulatory Medical Care Survey ED data sets. Ventilated patients were compared with ED patients admitted to the intensive care unit (ICU) and to all other ED visits. There were 3.6 million ED MV visits (95% confidence interval [CI], 3.2-4.0 million) over the study period. Sex, age, race, and payment source were similar for mechanically ventilated and ICU patients (P > .05 for all). Approximately 12.5% of ventilated patients underwent cardiopulmonary resuscitation compared with 1.7% of ICU admissions and 0.2% of all other ED visits (P < .0001). Accordingly, in-hospital mortality was significantly higher for ventilated patients (24%; 95% CI, 13.1%-34.9%) than both comparison groups (9.3% and 2.5%, respectively). Median LOS for ventilated patients was 197 minutes (interquartile range, 112-313 minutes) compared with 224 minutes for ICU admissions and 140 minutes for all other ED visits. Patients undergoing ED MV have particularly high in-hospital mortality rates, but their ED LOS is sufficient for implementation of evidence-based ventilator interventions. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. Pressure support-ventilation versus spontaneous breathing with "T-Tube" for interrupting the ventilation after cardiac operations

    PubMed Central

    Lourenço, Isabela Scali; Franco, Aline Marques; Bassetto, Solange; Rodrigues, Alfredo José

    2013-01-01

    Objective To compare pressure-support ventilation with spontaneous breathing through a T-tube for interrupting invasive mechanical ventilation in patients undergoing cardiac surgery with cardiopulmonary bypass. Methods Adults of both genders were randomly allocated to 30 minutes of either pressure-support ventilation or spontaneous ventilation with "T-tube" before extubation. Manovacuometry, ventilometry and clinical evaluation were performed before the operation, immediately before and after extubation, 1h and 12h after extubation. Results Twenty-eight patients were studied. There were no deaths or pulmonary complications. The mean aortic clamping time in the pressure support ventilation group was 62 ± 35 minutes and 68 ± 36 minutes in the T-tube group (P=0.651). The mean cardiopulmonary bypass duration in the pressure-support ventilation group was 89 ± 44 minutes and 82 ± 42 minutes in the T-tube group (P=0.75). The mean Tobin index in the pressure support ventilation group was 51 ± 25 and 64.5 ± 23 in the T-tube group (P=0.153). The duration of intensive care unit stay for the pressure support ventilation group was 2.1 ± 0.36 days and 2.3 ± 0.61 days in the T-tube group (P=0.581). The atelectasis score in the T-tube group was 0.6 ± 0.8 and 0.5 ± 0.6 (P=0.979) in the pressure support ventilation group. The study groups did not differ significantly in manovacuometric and ventilometric parameters and hospital evolution. Conclusion The two trial methods evaluated for interruption of mechanical ventilation did not affect the postoperative course of patients who underwent cardiac operations with cardiopulmonary bypass. PMID:24598949

  7. Tracheostomy ventilation versus diaphragmatic pacemaker ventilation in high spinal cord injury.

    PubMed

    Esclarín, A; Bravo, P; Arroyo, O; Mazaira, J; Garrido, H; Alcaraz, M A

    1994-10-01

    We have made a retrospective comparative study of patients with spinal cord injury, nine with a diaphragmatic pacemaker and 13 with mechanical ventilation. Clinical outcome, cost and subjective satisfaction with both modalities have been evaluated. The functional status was the same with both types of treatment. Proper management of an electric wheelchair and optimal phonation were attained, respectively, in 100% and 89% of pacers and in 77% and 77% of mechanically ventilated. The rate of hospital discharge and satisfaction with the treatment were significantly better for pacers. The time devoted to ventilatory assistance and cost were also more favourable in this group.

  8. Optimizing bag-valve-mask ventilation with a new mouth-to-bag resuscitator.

    PubMed

    Wagner-Berger, Horst G; Wenzel, Volker; Stallinger, Angelika; Voelckel, Wolfgang G; Rheinberger, Klaus; Augenstein, Sven; Herff, Holger; Idris, Ahamed H; Dörges, Volker; Lindner, Karl H; Hörmann, Christoph

    2003-02-01

    When ventilating an unintubated patient with a self-inflating bag, high peak inspiratory flow rates may result in high peak airway pressure with subsequent stomach inflation; this may occur frequently when rescuers without daily experience in bag-valve-mask ventilation need to perform advanced airway management. The purpose of this study was to assess the effects of a newly developed self-inflating bag (mouth-to-bag resuscitator; Ambu, Glostrup, Denmark) that limits peak inspiratory flow. A bench model simulating a patient with an unintubated airway was used, consisting of a face mask, manikin head, training lung (lung compliance, 100 ml/0.098 kPa (100 ml/cm H(2)O)); airway resistance, 0.39 kPa/l per second (4 cm H(2)O/l/s), oesophagus (LESP, 1.96 kPa (20 cm H(2)O)) and simulated stomach. Twenty nurses were randomised to ventilate the manikin for 1 min (respiratory rate: 12 per minute) with either a standard self-inflating bag or the mouth-to-bag resuscitator, which requires the rescuer to blow up a single-use balloon inside the self-inflating bag, which in turns displaces air towards the patient. When supplemental oxygen is added, ventilation with up to 100% oxygen may be obtained, since expired air is only used as the driving gas. The mouth-to-bag resuscitator therefore allows two instead of one hand sealing the mask on the patient's face. The volunteers were blinded to the experimental design of the model until completion of the experimental protocol. The mouth-to-bag resuscitator versus standard self-inflating bag resulted in significantly (P<0.05) higher mean+/-S.D. mask tidal volumes (1048+/-161 vs. 785+/-174 ml) and lung tidal volumes (911+/-148 vs. 678+/-157 ml), longer inspiratory times (1.7+/-0.4 vs. 1.4+/-0.4 s), but significantly lower peak inspiratory flow rates (50+/-9 vs. 62+/-13 l/min) and mask leakage (10+/-4 vs. 15+/-9%); peak inspiratory pressure (17+/-2 vs. 17+/-2 cm H(2)O) and stomach tidal volumes (16+/-30 vs. 18+/-35 ml) were comparable. In

  9. A prospective randomised, controlled clinical trial comparing medial and lateral entry pinning with lateral entry pinning for percutaneous fixation of displaced extension type supracondylar fractures of the humerus in children

    PubMed Central

    2012-01-01

    Objective To compare the efficacy of medial and lateral entry pinning with lateral entry pinning for percutaneous fixation of displaced (Gartland type II and type III) extension type supracondylar fractures of the humerus in children. Methods The study was a single center, prospective, randomized controlled clinical trial. Between October 2007 and September 2010, 160 patients who satisfy the inclusion and exclusion criterias were enrolled in the study, with 80 patients in each group. All the percutaneous pinning was done according to a uniform standardized technique. The patients were re-evaluated as outpatients at three weeks, six weeks and three months after the surgery. At three months follow-up visit, following informations were recorded as outcome measures: (i) Carrying angle (deg) (ii) passive range of elbow motion (deg) (iii) Flynn's criteria for grading, based on the loss of carrying angle and loss of total range of elbow motion. (iv) Baumann angle (deg) (v) Change in Baumann angle (deg) between the Intraoperative radiographs after the surgery and radiographs at three months follow-up visit (vi) loss of reduction grading, based on the change in the Baumann angle. Results There were no significant differences between the two groups with regard to base-line characteristics, withdrawals and complication rate. At three months follow-up visit, patients were evaluated by recording the various outcome measures. There were no significant differences between the two groups with regard to the various outcome measures such as carrying angle, passive range of elbow motion, Flynn grading, Baumann angle, change in the Baumann angle and loss of reduction grading. Conclusions If a uniform standardized operative technique is followed in each method, then the result of both the percutaneous fixation methods will be same in terms of safety and efficacy. PMID:22335830

  10. Neurally adjusted ventilator assist in very low birth weight infants: Current status

    PubMed Central

    Narchi, Hassib; Chedid, Fares

    2015-01-01

    Continuous improvements in perinatal care have resulted in increased survival of premature infants. Their immature lungs are prone to injury with mechanical ventilation and this may develop into chronic lung disease (CLD) or bronchopulmonary dysplasia. Strategies to minimize the risk of lung injury have been developed and include improved antenatal management (education, regionalization, steroids, and antibiotics), exogenous surfactant administration and reduction of barotrauma by using exclusive or early noninvasive ventilatory support. The most frequently used mode of assisted ventilation is pressure support ventilation that may lead to patient-ventilator asynchrony that is associated with poor outcome. Ventilator-induced diaphragmatic dysfunction or disuse atrophy of diaphragm fibers may also occur. This has led to the development of new ventilation modes including neurally adjusted ventilatory assist (NAVA). This ventilation mode is controlled by electrodes embedded within a nasogastric catheter which detect the electrical diaphragmatic activity (Edi) and transmit it to trigger the ventilator in synchrony with the patient’s own respiratory efforts. This permits the patient to control peak inspiratory pressure, mean airway pressure and tidal volume. Back up pressure control (PC) is provided when there is no Edi signal and no pneumatic trigger. Compared with standard conventional ventilation, NAVA improves blood gas regulation with lower peak inspiratory pressure and oxygen requirements in preterm infants. NAVA is safe mode of ventilation. The majority of studies have shown no significant adverse events in neonates ventilated with NAVA nor a difference in the rate of intraventricular hemorrhage, pneumothorax, or necrotizing enterocolitis when compared to conventional ventilation. Future large size randomized controlled trials should be established to compare NAVA with volume targeted and pressure controlled ventilation in newborns with mature respiratory drive

  11. Variable displacement blower

    DOEpatents

    Bookout, Charles C.; Stotts, Robert E.; Waring, Douglass R.; Folsom, Lawrence R.

    1986-01-01

    A blower having a stationary casing for rotatably supporting a rotor assembly having a series of open ended chambers arranged to close against the surrounding walls of the casing. Pistons are slidably mounted within each chamber with the center of rotation of the pistons being offset in regard to the center of rotation of the rotor assembly whereby the pistons reciprocate in the chambers as the rotor assembly turns. As inlet port communicates with the rotor assembly to deliver a working substance into the chamber as the pistons approach a top dead center position in the chamber while an outlet port also communicates with the rotor to exhaust the working substance as the pistons approach a bottom dead center position. The displacement of the blower is varied by adjusting the amount of eccentricity between the center of rotation of the pistons and the center of rotation of the rotor assembly.

  12. Patient-ventilator interaction and inspiratory effort during pressure support ventilation in patients with different pathologies.

    PubMed

    Nava, S; Bruschi, C; Fracchia, C; Braschi, A; Rubini, F

    1997-01-01

    respiratory failure due to different pathologies, led them to breathe with comparable pressure time product of the diaphragm. The majority of the patients showed mismatching with the ventilator, although this effect was more pronounced in the groups with chronic obstructive pulmonary disease.

  13. Fuselage ventilation under wind conditions

    NASA Technical Reports Server (NTRS)

    Stuart, J. W.

    1979-01-01

    To determine realistic fuselage ventilation rates for post-crash fires and full-scale fire tests, the effects on wind-about fuselage ventilation rate of various parameters were studied. The parameters investigated were fuselage size and shape, fuselage orientation and proximity to ground, fuselage-opening and location, and wind speed and direction.

  14. Transpired Air Collectors - Ventilation Preheating

    SciTech Connect

    Christensen, C.

    2006-06-22

    Many commercial and industrial buildings have high ventilation rates. Although all that fresh air is great for indoor air quality, heating it can be very expensive. This short (2-page) fact sheet describes a technology available to use solar energy to preheat ventilation air and dramatically reduce utility bills.

  15. Mechanical ventilation in abdominal surgery.

    PubMed

    Futier, E; Godet, T; Millot, A; Constantin, J-M; Jaber, S

    2014-01-01

    One of the key challenges in perioperative care is to reduce postoperative morbidity and mortality. Patients who develop postoperative morbidity but survive to leave hospital have often reduced functional independence and long-term survival. Mechanical ventilation provides a specific example that may help us to shift thinking from treatment to prevention of postoperative complications. Mechanical ventilation in patients undergoing surgery has long been considered only as a modality to ensure gas exchange while allowing maintenance of anesthesia with delivery of inhaled anesthetics. Evidence is accumulating, however, suggesting an association between intraoperative mechanical ventilation strategy and postoperative pulmonary function and clinical outcome in patients undergoing abdominal surgery. Non-protective ventilator settings, especially high tidal volume (VT) (>10-12mL/kg) and the use of very low level of positive end-expiratory pressure (PEEP) (PEEP<5cmH2O) or no PEEP, may cause alveolar overdistension and repetitive tidal recruitment leading to ventilator-associated lung injury in patients with healthy lungs. Stimulated by 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. In this review, we aimed at providing the most recent and relevant clinical evidence regarding the use of mechanical ventilation in patients undergoing abdominal surgery.

  16. Subject-ventilator synchrony during neural versus pneumatically triggered non-invasive helmet ventilation.

    PubMed

    Moerer, Onnen; Beck, Jennifer; Brander, Lukas; Costa, Roberta; Quintel, Michael; Slutsky, Arthur S; Brunet, Fabrice; Sinderby, Christer

    2008-09-01

    Patient-ventilator synchrony during non-invasive pressure support ventilation with the helmet device is often compromised when conventional pneumatic triggering and cycling-off were used. A possible solution to this shortcoming is to replace the pneumatic triggering with neural triggering and cycling-off-using the diaphragm electrical activity (EA(di)). This signal is insensitive to leaks and to the compliance of the ventilator circuit. Randomized, single-blinded, experimental study. University Hospital. PARTICIPANTS AND SUBJECTS: Seven healthy human volunteers. Pneumatic triggering and cycling-off were compared to neural triggering and cycling-off during NIV delivered with the helmet. Triggering and cycling-off delays, wasted efforts, and breathing comfort were determined during restricted breathing efforts (<20% of voluntary maximum EA(di)) with various combinations of pressure support (PSV) (5, 10, 20 cm H(2)O) and respiratory rates (10, 20, 30 breath/min). During pneumatic triggering and cycling-off, the subject-ventilator synchrony was progressively more impaired with increasing respiratory rate and levels of PSV (p < 0.001). During neural triggering and cycling-off, effect of increasing respiratory rate and levels of PSV on subject-ventilator synchrony was minimal. Breathing comfort was higher during neural triggering than during pneumatic triggering (p < 0.001). The present study demonstrates in healthy subjects that subject-ventilator synchrony, trigger effort, and breathing comfort with a helmet interface are considerably less impaired during increasing levels of PSV and respiratory rates with neural triggering and cycling-off, compared to conventional pneumatic triggering and cycling-off.

  17. Inhalation therapy in mechanical ventilation

    PubMed Central

    Maccari, Juçara Gasparetto; Teixeira, Cassiano; Gazzana, Marcelo Basso; Savi, Augusto; Dexheimer-Neto, Felippe Leopoldo; Knorst, Marli Maria

    2015-01-01

    Patients with obstructive lung disease often require ventilatory support via invasive or noninvasive mechanical ventilation, depending on the severity of the exacerbation. The use of inhaled bronchodilators can significantly reduce airway resistance, contributing to the improvement of respiratory mechanics and patient-ventilator synchrony. Although various studies have been published on this topic, little is known about the effectiveness of the bronchodilators routinely prescribed for patients on mechanical ventilation or about the deposition of those drugs throughout the lungs. The inhaled bronchodilators most commonly used in ICUs are beta adrenergic agonists and anticholinergics. Various factors might influence the effect of bronchodilators, including ventilation mode, position of the spacer in the circuit, tube size, formulation, drug dose, severity of the disease, and patient-ventilator synchrony. Knowledge of the pharmacological properties of bronchodilators and the appropriate techniques for their administration is fundamental to optimizing the treatment of these patients. PMID:26578139

  18. Evaluation of building ventilation systems

    SciTech Connect

    Hughes, R.T.; O'Brien, D.M.

    1986-04-01

    Over the past several years, NIOSH has responded to health hazard evaluation requests from workers in dozens of office environments. Typically, the employees have complained of headache, eye and upper respiratory tract irritation, dizziness, lethargy and the inability to concentrate. Most often inadequate ventilation has been blamed for these complaints. Of paramount importance in the evaluation and correction of these problems is an effective evaluation of the building's ventilation system. Heating, ventilating and air-conditioning conditions that can cause worker stresses include: migration of odors or chemical hazards between building areas; reentrainment of exhaust from building fume hoods or through heat wheels; buildup of microorganisms in the HVAC system components; and poor odor or environmental control due to insufficient fresh outdoor air or system heating or cooling malfunction. The purpose of this paper is to provide an overview of building ventilation systems, the ventilation problems associated with poorly designed or operating systems, and the methodology for effectively evaluating system performance.

  19. Difficult weaning from mechanical ventilation.

    PubMed

    Oh, T E

    1994-07-01

    Weaning from mechanical ventilation may be influenced by factors relating to equipment, techniques and procedures. Criteria to initiate weaning and predictors of weaning outcome are generally unreliable, but mechanical work of breathing, the tidal volume: frequency ratio and the inspiratory pressure: maximal inspiratory pressure ratio may anticipate those likely to fail weaning. The optimal weaning ventilatory mode is not known, but intermittent mandatory ventilation, pressure support ventilation, and continuous positive pressure ventilation are the most commonly used. The resistances of individual components of breathing circuits are extremely important. Blow-by heated humidifiers and ventilators which compensate for the impedances of their inspiratory demand valves impose clinically acceptable spontaneous breathing loads. Close monitoring, adequate respiratory muscle rest, attention to mineral deficiencies, nutrition and pulmonary hygiene are also important parts of the weaning process.

  20. Cardiorespiratory Mechanical Simulator for In Vitro Testing of Impedance Minute Ventilation Sensors in Cardiac Pacemakers.

    PubMed

    Marcelli, Emanuela; Cercenelli, Laura

    2016-01-01

    We developed a cardiorespiratory mechanical simulator (CRMS), a system able to reproduce both the cardiac and respiratory movements, intended to be used for in vitro testing of impedance minute ventilation (iMV) sensors in cardiac pacemakers. The simulator consists of two actuators anchored to a human thorax model and a software interface to control the actuators and to acquire/process impedance signals. The actuators can be driven separately or simultaneously to reproduce the cardiac longitudinal shortening at a programmable heart rate and the diaphragm displacement at a programmable respiratory rate (RR). A standard bipolar pacing lead moving with the actuators and a pacemaker case fixed to the thorax model have been used to measure impedance (Z) variations during the simulated cardiorespiratory movements. The software is able to discriminate the low-frequency component because of respiration (Z(R)) from the high-frequency ripple because of cardiac effect (Z(C)). Impedance minute ventilation is continuously calculated from Z(R) and RR. From preliminary tests, the CRMS proved to be a reliable simulator for in vitro evaluation of iMV sensors. Respiration impedance recordings collected during cardiorespiratory movements reproduced by the CRMS were comparable in morphology and amplitude with in vivo assessments of transthoracic impedance variations.

  1. 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

  2. Enteral alimentation and gastrointestinal bleeding in mechanically ventilated patients.

    PubMed

    Pingleton, S K; Hadzima, S K

    1983-01-01

    The incidence of upper gastrointestinal (GI) bleeding in mechanically ventilated ICU patients receiving enteral alimentation was reviewed and compared to bleeding occurring in ventilated patients receiving prophylactic antacids or cimetidine. Of 250 patients admitted to our ICU during a 1-yr time period, 43 ventilated patients were studied. Patients in each group were comparable with respect to age, respiratory diagnosis, number of GI hemorrhage risk factors, and number of ventilator, ICU, and hospital days. Twenty-one patients had evidence of GI bleeding. Fourteen of 20 patients receiving antacids and 7 of 9 patients receiving cimetidine had evidence of GI bleeding. No bleeding occurred in 14 patients receiving enteral alimentation. Complications of enteral alimentation were few and none required discontinuation of enteral alimentation. Our preliminary data suggest the role of enteral alimentation in critically ill patients may include not only protection against malnutrition but also protection against GI bleeding.

  3. Ventilator-induced diaphragmatic dysfunction.

    PubMed

    Petrof, Basil J; Jaber, Samir; Matecki, Stefan

    2010-02-01

    Diaphragmatic function is a major determinant of the ability to successfully wean patients from mechanical ventilation. There is increasing recognition of a condition termed ventilator-induced diaphragmatic dysfunction. The purpose of the present review is to present evidence that mechanical ventilation can itself be a cause of diaphragmatic dysfunction, to outline our current understanding of the cellular mechanisms responsible for this phenomenon, and to discuss the implications of recent research for future therapeutic strategies. Many critically ill patients demonstrate diaphragmatic weakness. A large body of evidence from animal models, and more limited data from humans, indicates that mechanical ventilation can cause muscle fiber injury and atrophy within the diaphragm. Current data support a complex underlying pathophysiology involving oxidative stress and the activation of several intracellular proteolytic pathways involved in degradation of the contractile apparatus. This includes the calpain, caspase, and ubiquitin-proteasome systems. In addition, there is a simultaneous downregulation of protein synthesis pathways. Studies in animal models suggest that future therapies may be able to specifically target these processes, whereas for the time being current preventive measures in humans are primarily based upon allowing persistent diaphragmatic activation during mechanical ventilation. Diaphragmatic dysfunction is common in mechanically ventilated patients and is a likely cause of weaning failure. Recently, there has been a great expansion in our knowledge of how mechanical ventilation can adversely affect diaphragmatic structure and function. Future studies need to better define the evolution and mechanistic basis for ventilator-induced diaphragmatic dysfunction in humans, in order to allow the development of mechanical ventilation strategies and pharmacologic agents that will decrease the incidence of ventilator-induced diaphragmatic dysfunction.

  4. Quality of life of ALS and LIS patients with and without invasive mechanical ventilation.

    PubMed

    Rousseau, Marie-Christine; Pietra, Stéphane; Blaya, José; Catala, Anne

    2011-10-01

    There are very few studies where quality of life (QOL) is assessed in patients with complete physical and functional disability and dependence to invasive mechanical ventilation (IV). We compared QOL of amyotrophic lateral sclerosis (ALS) and locked-in-syndrome (LIS) patients with invasive mechanical ventilation to ALS and LIS patients without mechanical invasive ventilation. Thirty-four patients, 27 with ALS and seven with LIS (vascular or tumoral aetiology) were included in the study. Twelve had invasive ventilation, 22 had non-invasive ventilation, and in the non-invasive ventilation group, five of them had ventilation via mask. The following scales were used for patients: ALS Functional Rating Scale (ALSFRS), McGILL, Short-Form 36 (SF36), Beck Depression Inventory-II, the Toronto Alexithymia Scale and the anxiety inventory of Spielberger. Mean ALSFRS scores were significantly lower in the invasive ventilation group (IV) than in the non-invasive ventilation group. McGILL and SF36 were not significantly different between the IV group and the non-invasive ventilation group; there were no significant differences between the two groups for others scales either. Comparison between IV group and LIS without invasive mechanical ventilation revealed no significant difference for SF36 and McGILL QOL scores. QOL was not significantly different between the IV and not invasively ventilated patients, but ALSFRS was significantly lower in the IV group, and comparison of QOL scores between non-ventilated LIS patients who had the same score of dependence that invasively ventilated patients did not show any difference. Invasive mechanical ventilation for patients who accept tracheotomy allows life prolongation and their QOL is not affected; medical teams should be aware of that.

  5. Comparison of patient-ventilator asynchrony during pressure support ventilation and proportional assist ventilation modes in surgical Intensive Care Unit: A randomized crossover study

    PubMed Central

    Gautam, Parshotam Lal; Kaur, Gaganjot; Katyal, Sunil; Gupta, Ruchi; Sandhu, Preetveen; Gautam, Nikhil

    2016-01-01

    Background: The patient-ventilator asynchrony is almost observed in all modes of ventilation, and this asynchrony affects lung mechanics adversely resulting in deleterious outcome. Innovations and advances in ventilator technology have been trying to overcome this problem by designing newer modes of ventilation. Pressure support ventilation (PSV) is a commonly used flow-cycled mode where a constant pressure is delivered by ventilator. Proportional assist ventilation (PAV) is a new dynamic inspiratory pressure assistance and is supposed to be better than PSV for synchrony and tolerance, but reports are still controversial. Moreover, most of these studies are conducted in chronic obstructive pulmonary disease patients with respiratory failure; the results of these studies may not be applicable to surgical patients. Thus, we proposed to do compare these two modes in surgical Intensive Care Unit (ICU) patients as a randomized crossover study. Aims: Comparison of patient-ventilator asynchrony between PSV and PAV plus (PAV+) in surgical patients while weaning. Subjects and Methods: After approval by the Hospital Ethics Committee, we enrolled twenty patients from surgical ICU of tertiary care institute. The patients were ventilated with pressure support mode (PSV) and PAV+ for 12 h as a crossover from one mode to another after 6 h while weaning. Results: Average age and weight of patients were 41.80 ± 15.20 years (mean ± standard deviation [SD]) and 66.50 ± 12.47 (mean ± SD) kg, respectively. Comparing the asynchronies between the two modes, the mean number of total asynchronous recorded breaths in PSV was 7.05 ± 0.83 and 4.35 ± 5.62, respectively, during sleep and awake state, while the same were 6.75 ± 112.24 and 10.85 ± 11.33 in PAV+. Conclusion: Both PSV and PAV+ modes of ventilation performed similarly for patient-ventilator synchrony in surgical patients. In surgical patients with acute respiratory failure, dynamic inspiratory pressure assistance modalities

  6. The Ventilation, Heating and Lighting of Hospital Wards

    PubMed Central

    Watt, James

    1933-01-01

    History of ventilation in last 100 years, showing reversal of ideas and influence of sanatorium idea. Physiology of cool moving air. How it affects metabolism, heat-loss and heat-production. Relation to sunlight. Reactive capacity of the individual. Practice of these teachings, as illustrated by sanatorium treatment of tuberculosis and by open-air schools. Exposure to cooling air a powerful therapeutic agent. Infrequent occurrence in sanatoria of diseases or complications often ascribed to cold. Dilution of infection. Applicability to diseases other than tuberculosis. Shock and old age. Perflation and diffusion, their relative values. Uniformity or variability of effect desirable? Incompatibility of good ventilation and ordinary standards of heating. Former the more important. Conclusion that ward temperatures may be lowered without harm. Measures necessary to compensate, clothing, classification of patients, small wards. Changing standards of comfort. Psychological effects. Systems of ventilation in hospital wards. Mechanical by propulsion or extraction being displaced by natural system, usually by cross-window ventilation. Supplementary ventilators. Objection to heating of incoming air. Fallibility of human factor in management. Sash versus casement windows. Hoppers. Austral window. Orientation and exposure of wards. Ventilation of small wards. Proportion of window space to solid wall. Balconies. Floor space. Heating of wards. Heating of air or floor or walls. Open fires. Value of radiant heat. Steam or water under low or high pressure. Radiators or pipes. Lighting. Avoidance of glare from windows. Arrangement of beds in wards. Colour of walls. Blinds and curtains. Artificial lighting. ImagesFig. 1Fig. 2Fig. 3Fig. 4Fig. 5 PMID:19989481

  7. Marked pericardial inhomogeneity of specific ventilation at total lung capacity and beyond.

    PubMed

    Sun, Yanping; Butler, James P; Lindholm, Peter; Walvick, Ronn P; Loring, Stephen H; Gereige, Jessica; Ferrigno, Massimo; Albert, Mitchell S

    2009-10-31

    We measured regional ventilation at 1l above functional residual capacity (FRC+1L) and total lung capacity (TLC) in three normal subjects and four elite breath-hold divers, and above TLC after glossopharyngeal insufflation (TLC+GI) in the divers. Hyperpolarized (3)He MRI was used to map the local ventilation per unit volume over the entire lung. At TLC and above, there was markedly increased regional ventilation of the lungs in the pericardial region compared with the relatively uniform ventilation throughout the rest of the lung. The distribution of fractional ventilation regionally was relatively uniform at FRC+1L, with a small non-gravitational cephalocaudal gradient of specific ventilation in the supine posture. Our observations at high lung volumes are consistent with the effect of high pleural tension in the concave pericardial region, which promotes expansion of the subjacent lung, leading to a higher local effective compliance and a higher specific ventilation.

  8. A study on the ventilation method for a factory exposed to high temperature

    NASA Astrophysics Data System (ADS)

    Kim, Y.; Lee, E.; Jeong, H.; Chung, H.

    2015-09-01

    On this work, the importance of industrial ventilation was investigated and examined the theoretical point and problems about general ventilation of factory exposed on high temperature during summer. As a case study, the ventilation planning of the PCB etching process for an electronic company was carried out and each of those characteristics were compared by installing actual ventilation systems and measuring the changing state of the working environment in accordance with ventilation method during summer. The purpose of the study is to present an efficient ventilation method for a factory with a closed structure under high temperature environment. In summary, for a factory with a sealed structure such as the target PCB manufacturing factory in this study, the forced supply and exhaust method was the most appropriate ventilation method for maintaining a low indoor air temperature and for keeping the contaminated air of the factory below the hazardous level.

  9. 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.

  10. The mitigation of pulsation in ventilated supercavities

    NASA Astrophysics Data System (ADS)

    Skidmore, Grant

    It is desirable to use ventilated supercavities to reduce the drag created by underwater bodies and obtain velocities much higher than those that are possible with fully wetted bodies. Ventilated supercavities, however, are prone to an autoresonant phenomenon known as pulsation where the supercavity radius and length oscillate with time. These oscillations in radius and length are oftentimes severe enough to cause issues with body stability and control. In this dissertation, a method to mitigate pulsation in ventilated supercavities is presented. The method, which modulates or adds a sinusoidal component to the ventilation rate, is shown to suppress pulsation numerically, experimentally, and computationally. Additionally in this dissertation, the near-field acoustic characteristics of twin vortex, re-entrant jet, and pulsating ventilated supercavities are studied experimentally. This study is then repeated computationally, with a focus on the generation and mitigation of pulsation in ventilated supercavities. The study of the near-field radiated noise from supercavities shows that pulsating supercavities generate noise that is two orders of magnitude (i.e., 40 dB) greater in level than that from comparable twin vortex and re-entrant jet supercavities. For pulsating supercavities, it is found that the interior cavity pressure and near-field radiated noise are both monotonic in frequency, with said frequency being related to the freestream velocity and the length of the dominant waves on the supercavity air/water interface. For pulsating supercavities, it is also found that, at the pulsation frequency, the cavity interior pressure spectrum level is related to the near-field and far-field noise spectrum level through spherical spreading of the sound waves from the supercavity interface. As a result, the cavity interior pressure can be used as a measure of the radiated noise. The developed method for mitigating pulsation in ventilated supercavities is shown to

  11. Comparison of the New Adult Ventilator-Associated Event Criteria to the Centers for Disease Control and Prevention Pediatric Ventilator-Associated Pneumonia Definition (PNU2) in a Population of Pediatric Traumatic Brain Injury Patients.

    PubMed

    Cirulis, Meghan M; Hamele, Mitchell T; Stockmann, Chris R; Bennett, Tellen D; Bratton, Susan L

    2016-02-01

    The new Centers for Disease Control and Prevention paradigm for ventilator-associated events is intended to simplify surveillance of infectious and noninfectious complications of mechanical ventilation in adults. We assessed the ventilator-associated events algorithm in pediatric patients. A retrospective observational cohort study. This single-center study took place in a PICU at an urban academic medical facility. Pediatric (ages 0-18 yr old) trauma patients with moderate-to-severe traumatic brain injury ventilated for greater than or equal to 2 days. We assessed for pediatric ventilator-associated pneumonia (as defined by current Centers for Disease Control and Prevention PNU2 guidelines), adult ventilator-associated events, and an experimental ventilator-associated events definition modified for pediatric patients. We compared ventilator-associated events to ventilator-associated pneumonia to calculate the test characteristics. Thirty-nine of 119 patients (33%) developed ventilator-associated pneumonia. Sensitivity of the adult ventilator-associated condition definition was 23% (95% CI, 11-39%), which increased to 56% (95% CI, 40-72%) using the modified pediatric ventilator-associated pneumonia criterion. Specificity reached 100% for both original and modified pediatric probable ventilator-associated pneumonia using ventilator-associated events criteria. Children who developed ventilator-associated pneumonia or ventilator-associated condition had similar baseline characteristics: age, mechanism of injury, injury severity scores, and use of an intracranial pressure monitor. Diagnosis of ventilator-associated pneumonia and ventilator-associated condition portended similarly unfavorable outcomes: longer median duration of ventilation, ICU and hospital length of stay, and more discharges to rehabilitation, home health, or nursing care compared with patients with no pulmonary complication. Both current and modified ventilator-associated events criteria have poor

  12. Displacement Cascade Damage Production in Metals

    SciTech Connect

    Stoller, Roger E; Malerba, Lorenzo; Nordlund, Kai

    2015-01-01

    Radiation-induced changes in microstructure and mechanical properties in structural materials are the result of a complex set of physical processes initiated by the collision between an energetic particle (neutron or ion) and an atom in the lattice. This primary damage event is called an atomic displacement cascade. The simplest description of a displacement cascade is to view it as a series of many billiard-ball-like elastic collisions among the atoms in the material. This chapter describes the formation and evolution of this primary radiation damage mechanism to provide an overview of how stable defects are formed by displacement cascades, as well as the nature and morphology of the defects themselves. The impact of the relevant variables such as cascade energy and irradiation temperature is discussed, and defect formation in different materials is compared.

  13. Ventilation and respiratory mechanics.

    PubMed

    Sheel, Andrew William; Romer, Lee M

    2012-04-01

    During dynamic exercise, the healthy pulmonary system faces several major challenges, including decreases in mixed venous oxygen content and increases in mixed venous carbon dioxide. As such, the ventilatory demand is increased, while the rising cardiac output means that blood will have considerably less time in the pulmonary capillaries to accomplish gas exchange. Blood gas homeostasis must be accomplished by precise regulation of alveolar ventilation via medullary neural networks and sensory reflex mechanisms. It is equally important that cardiovascular and pulmonary system responses to exercise be precisely matched to the increase in metabolic requirements, and that the substantial gas transport needs of both respiratory and locomotor muscles be considered. Our article addresses each of these topics with emphasis on the healthy, young adult exercising in normoxia. We review recent evidence concerning how exercise hyperpnea influences sympathetic vasoconstrictor outflow and the effect this might have on the ability to perform muscular work. We also review sex-based differences in lung mechanics.

  14. Solar ventilation and tempering

    NASA Astrophysics Data System (ADS)

    Adámek, Karel; Pavlů, Miloš; Bandouch, Milan

    2014-08-01

    The paper presents basic information about solar panels, designed, realized and used for solar ventilation of rooms. Used method of numerical flow simulation gives good overview about warming and flowing of the air in several kinds of realized panels (window, facade, chimney). Yearlong measurements give a good base for calculations of economic return of invested capital. The operation of the system in transient period (spring, autumn) prolongs the period without classical heating of the room or building, in winter the classical heating is supported. In the summer period the system, furnished with chimney, can exhaust inner warm air together with necessary cooling of the system by gravity circulation, only. System needs not any invoiced energy source; it is supplied entirely by solar energy. Large building systems are supported by classical electric fan respectively.

  15. Cardiac gated ventilation

    SciTech Connect

    Hanson, C.W. III; Hoffman, E.A.

    1995-12-31

    There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. The authors evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50 msec scan aperture. Multi slice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. The authors observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a non-failing model of the heart.

  16. 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.

  17. [High-frequency ventilation. Development of new ventilation systems--experimental and clinical results].

    PubMed

    Mutz, N

    1984-01-01

    Based on the well known High Frequency Jet Ventilation (HFJV) two modified types of High Frequency Ventilation, Forced Diffusion Ventilation (FDV) and High Frequency Pulsation (HFP) have been developed. Both systems are designed to allow ventilation with very small volume portions in the upper range of HFV frequencies. In dog experiments sufficient gas exchange could be maintained during FDV up to frequencies 3000 per minute and even with an uninterrupted "continuous" jet entering the lungs on carina level. With this mode of ventilation lung could be kept in a resting position. Due to particular configuration of a pair of nozzles at the tip of a modified endotracheal catheter fresh gas is forced down the airways along the inner edges of bifurcations towards the lung periphery. At the same time stale gas leaves the lung via the remaining cross section of the airways. Thus a continuous scavanging process can be established without significant lung inflation. This mechanisms are not met during HFP. Therefore the range of frequencies achievable with this type of ventilation is significantly lower (250 to 500/min.) and "tidal volumes" are much higher. However, they are still beyond the anatomical dead space which suggest again a contribution of alternative mechanisms to gas transport. The impact of both types of HFV on gas exchange and pressure-flow conditions were studied in lung models as well as in animal experiments. FDV and HFP were also applied successfully to a group of 23 patients undergoing major lung surgery. In all patients it was possible to maintain excellent gas exchange throughout the whole surgical procedure. The exposure of the surgical field was much more quiet as compared to IPPV. Due to the small tidal volumes lung pressures can be kept much lower and gas losses via the open bronchi and lung surface are reduced dramatically.

  18. Delivery of tidal volume from four anaesthesia ventilators during volume-controlled ventilation: a bench study.

    PubMed

    Wallon, G; Bonnet, A; Guérin, C

    2013-06-01

    Tidal volume (V(T)) must be accurately delivered by anaesthesia ventilators in the volume-controlled ventilation mode in order for lung protective ventilation to be effective. However, the impact of fresh gas flow (FGF) and lung mechanics on delivery of V(T) by the newest anaesthesia ventilators has not been reported. We measured delivered V(T) (V(TI)) from four anaesthesia ventilators (Aisys™, Flow-i™, Primus™, and Zeus™) on a pneumatic test lung set with three combinations of lung compliance (C, ml cm H2O(-1)) and resistance (R, cm H2O litre(-1) s(-2)): C60R5, C30R5, C60R20. For each CR, three FGF rates (0.5, 3, 10 litre min(-1)) were investigated at three set V(T)s (300, 500, 800 ml) and two values of PEEP (0 and 10 cm H2O). The volume error = [(V(TI) - V(Tset))/V(Tset)] ×100 was computed in body temperature and pressure-saturated conditions and compared using analysis of variance. For each CR and each set V(T), the absolute value of the volume error significantly declined from Aisys™ to Flow-i™, Zeus™, and Primus™. For C60R5, these values were 12.5% for Aisys™, 5% for Flow-i™ and Zeus™, and 0% for Primus™. With an increase in FGF, absolute values of the volume error increased only for Aisys™ and Zeus™. However, in C30R5, the volume error was minimal at mid-FGF for Aisys™. The results were similar at PEEP 10 cm H2O. Under experimental conditions, the volume error differed significantly between the four new anaesthesia ventilators tested and was influenced by FGF, although this effect may not be clinically relevant.

  19. Pressure support ventilation decreases inspiratory work of breathing during general anesthesia and spontaneous ventilation.

    PubMed

    Christie, J M; Smith, R A

    1992-08-01

    Spontaneous ventilation may offer advantages over controlled mechanical ventilation (CMV), but increase in work of breathing may diminish its usefulness. During general anesthesia, respiratory depression and increased work of breathing often preclude spontaneous ventilation, and patients then receive CMV. We compared the inspiratory work of breathing of anesthetized patients who breathed with pressure support ventilation (PSV) with that associated with a demand gas flow and a standard anesthesia circle system. We studied nine consenting patients who underwent general inhaled anesthesia with or without regional supplementation. An anesthesia/ventilator system (Siemens 900D, Solna, Sweden) provided PSV (5 cm H2O) or demand gas flow during spontaneous inspiration. Gas flow during demand breathing and PSV was initiated when inspiration produced a 2-cm H2O reduction in airway pressure. An anesthesia machine (Dräger Narkomed 3, Telford, Pa.) provided a gas flow rate of 6 L/min through a standard semiclosed circle system. Airway pressure, airway gas flow rate, and esophageal pressure were continuously transduced, and data or signals were conveyed to a computer. Tidal volume and respiratory rate were computed from the flow curve. The inspiratory work of breathing was calculated as the integral of the area subserved by a plot of esophageal pressure and tidal volume during inspiration. Heart rate and mean arterial blood pressure were recorded, and arterial blood was sampled for gas tension and pH analysis. No differences were found in pHa, Paco2, Pao2, tidal volume, respiratory rate, heart rate, or mean arterial blood pressure among the three modes of ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Comparison of actual tidal volume in neonatal lung model volume control ventilation using three ventilators.

    PubMed

    Toyama, H; Endo, Y; Ejima, Y; Matsubara, M; Kurosawa, S

    2011-07-01

    In neonates, small changes in tidal volumes (V(T)) may lead to complications. Previous studies have shown a significant difference between ventilator-measured tidal volume and tidal volume delivered (actual V(T)). We evaluated the accuracy of three different ventilators to deliver small V(T) during volume-controlled ventilation. We tested Servo 300, 840 ventilator and Evita 4 Neoflow ventilators with lung models simulating normal and injured neonatal lung compliance models. Gas volume delivered from the ventilator into the test circuit (V(TV)) and actual V(T) to the test lung were measured using Ventrak respiration monitors at set V(T) (30 ml). The gas volume increase of the breathing circuit was then calculated. Tidal volumes of the SV300 and PB840 in both lung models were similar to the set V(T) and the actual tidal volumes in the injured model (20.7 ml and 19.8 ml, respectively) were significantly less than that in the normal model (27.4 ml and 23.4 ml). PB840 with circuit compliance compensation could not improve the actual V(T). V(TV) of the EV4N in the normal and the injured models (37.8 ml and 46.6 ml) were markedly increased compared with set V(T), and actual V(T) were similar to set V(T) in the normal and injured model (30.2 ml and 31.9 ml, respectively). EV4N measuring V(T) close to the lung could match actual V(T) to almost the same value as the set V(T) however the gas volume of the breathing circuit was increased. If an accurate value for the patient's actual V(T) is needed, this V(T) must be measured by a sensor located between the Y-piece and the tracheal tube.

  1. Effects of Volume Guaranteed Ventilation Combined with Two Different Modes in Preterm Infants.

    PubMed

    Unal, Sezin; Ergenekon, Ebru; Aktas, Selma; Altuntas, Nilgun; Beken, Serdar; Kazanci, Ebru; Kulali, Ferit; Gulbahar, Ozlem; Hirfanoglu, Ibrahim M; Onal, Esra; Turkyilmaz, Canan; Koc, Esin; Atalay, Yildiz

    2017-07-11

    Volume-controlled ventilation modes have been shown to reduce duration of mechanical ventilation, incidence of chronic lung disease, failure of primary mode of ventilation, hypocarbia, severe intraventricular hemorrhage, pneumothorax, and periventricular leukomalacia in preterm infants when compared with pressure limited ventilation modes. Volume-guarantee (VG) ventilation is the most commonly used mode for volume-controlled ventilation. Assist control, pressure-support ventilation (PSV), and synchronized intermittent mandatory ventilation (SIMV) can be combined with VG; however, there is a lack of knowledge on the superiority of each regarding clinical outcomes. Therefore, we investigated the effects of SIMV+VG and PSV+VG on ventilatory parameters, pulmonary inflammation, morbidity, and mortality in preterm infants. Preterm infants who were born in our hospital between 24-32 weeks gestation and needed mechanical ventilation for respiratory distress syndrome were considered eligible. Patients requiring high-frequency oscillatory ventilation for primary treatment were excluded. Subjects were randomized to either SIMV+VG or PSV+VG. Continuously recorded ventilatory parameters, clinical data, blood gas values, and tracheal aspirate cytokine levels were analyzed. The study enrolled 42 subjects. Clinical data were similar between groups. PSV+VG delivered closer tidal volumes to set tidal volumes (60% vs 49%, P = .02). Clinical data, including days on ventilation, morbidity, and mortality, were similar between groups. Chronic lung disease occurred less often and heart rate was lower in subjects who were ventilated with PSV+VG. The incidence of hypocarbia and hypercarbia were similar. Interleukin-β in the tracheal aspirates increased during both modes. PSV+VG provided closer tidal volumes to the set value in ventilated preterm infants with respiratory distress syndrome and was not associated with overventilation or a difference in mortality or morbidity when compared to

  2. Effects of body temperature on ventilator-induced lung injury.

    PubMed

    Akinci, Ozkan I; Celik, Mehmet; Mutlu, Gökhan M; Martino, Janice M; Tugrul, Simru; Ozcan, Perihan E; Yilmazbayhan, Dilek; Yeldandi, Anjana V; Turkoz, Kemal H; Kiran, Bayram; Telci, Lütfi; Cakar, Nahit

    2005-03-01

    To evaluate the effects of body temperature on ventilator-induced lung injury. Thirty-four male Sprague-Dawley rats were randomized into 6 groups based on their body temperature (normothermia, 37 +/- 1 degrees C; hypothermia, 31 +/- 1 degrees C; hyperthermia, 41 +/- 1 degrees C). Ventilator-induced lung injury was achieved by ventilating for 1 hour with pressure-controlled ventilation mode set at peak inspiratory pressure (PIP) of 30 cmH2O (high pressure, or HP) and positive end-expiratory pressure (PEEP) of 0 cmH2O. In control subjects, PIP was set at 14 cmH2O (low pressure, or LP) and PEEP set at 0 cmH2O. Systemic chemokine and cytokine (tumor necrosis factor alpha , interleukin 1 beta , interleukin 6, and monocyte chemoattractant protein 1) levels were measured. The lungs were assessed for histological changes. Serum chemokines and cytokines were significantly elevated in the hyperthermia HP group compared with all 3 groups, LP (control), normothermia HP, and hypothermia HP. Oxygenation was better but not statistically significant in hypothermia HP compared with other HP groups. Cumulative mean histology scores were higher in hyperthermia HP and normothermia HP groups compared with control and normothermia HP groups. Concomitant hyperthermia increased systemic inflammatory response during HP ventilation. Although hypothermia decreased local inflammation in the lung, it did not completely attenuate systemic inflammatory response associated with HP ventilation.

  3. Cardiopulmonary function and oxygen delivery during total liquid ventilation.

    PubMed

    Tsagogiorgas, Charalambos; Alb, Markus; Herrmann, Peter; Quintel, Michael; Meinhardt, Juergen P

    2011-10-01

    Total liquid ventilation (TLV) with perfluorocarbons has shown to improve cardiopulmonary function in the injured and immature lung; however there remains controversy over the normal lung. Hemodynamic effects of TLV in the normal lung currently remain undetermined. This study compared changes in cardiopulmonary and circulatory function caused by either liquid or gas tidal volume ventilation. In a prospective, controlled study, 12 non-injured anesthetized, adult New Zealand rabbits were primarily conventionally gas-ventilated (CGV). After instrumentation for continuous recording of arterial (AP), central venous (CVP), left artrial (LAP), pulmonary arterial pressures (PAP), and cardiac output (CO) animals were randomized into (1) CGV group and (2) TLV group. In the TLV group partial liquid ventilation was initiated with instillation of perfluoroctylbromide (12 ml/kg). After 15 min, TLV was established for 3 hr applying a volume-controlled, pressure-limited, time-cycled ventilation mode using a double-piston configured TLV. Controls (CGV) remained gas-ventilated throughout the experiment. During TLV, heart rate, CO, PAP, MAP, CVP, and LAP as well as derived hemodynamic variables, arterial and mixed venous blood gases, oxygen delivery, PVR, and SVR did not differ significantly compared to CGV. Liquid tidal volumes suitable for long-term TLV in non-injured rabbits do not significantly impair CO, blood pressure, and oxygen dynamics when compared to CGV. Copyright © 2011 Wiley-Liss, Inc.

  4. Isothermal Multiple Displacement Amplification

    PubMed Central

    Luthra, Rajyalakshmi; Medeiros, L. Jeffrey

    2004-01-01

    Isothermal multiple strand displacement amplification (IMDA) of the whole human genome is a promising method for procuring abundant DNA from valuable and often limited clinical specimens. However, whether DNA generated by this method is of high quality and a faithful replication of the DNA in the original specimen, allowing for subsequent molecular diagnostic testing, requires verification. In this study, we evaluated the suitability of IMDA-generated DNA (IMDA-DNA) for detecting antigen receptor gene rearrangements, chromosomal translocations, and gene mutations using Southern blot analysis, polymerase chain reaction (PCR) methods, or sequencing methods in 28 lymphoma and leukemia clinical specimens. Molecular testing before and after whole genome amplification of these specimens using the IMDA technique showed concordance in 27 of 28 (96%) specimens. Analysis of IMDA-DNA by Southern blot analysis detected restriction fragments >12 kilobases long. No amplification bias was observed at all loci tested demonstrating that this method can be useful in generating large amounts of unbiased, high molecular weight DNA from limited clinical specimens. PMID:15269301

  5. Laser optical displacement system

    NASA Astrophysics Data System (ADS)

    Starritt, Larry W.; Matthews, Larryl K.

    1995-04-01

    The current quality of our nations bridges is on a decline. There are roughly half a million highway bridges in the United States and out of the half a million more than 200,000 are deficient. With catastrophic failure of bridges causing the loss of life and property, the need for bridge inspection and maintenance is evident. When the Silver Bridge that crossed the Ohio River collapsed in December 1967, 46 people were killed. The failure to prevent the disaster was attributed to the poor inspection techniques used by the bridge inspectors. Current inspection techniques depend on humans being able to recognize structural imperfections without the aid of instrumentation. The Federal-Aid Highway Act of 1968 mandated both national bridge inspection standards and training for bridge inspectors. This act has encouraged the development of instruments that would allow inspectors to perform more complete inspections of bridges. To improve the quality of inspection and data, there is a great need for proven methods and instruments used to acquire data. The Laser Optical Displacement System (L.O.D.S.) developed at New Mexico State University by the Optical and Materials Science Lab is such a device. The L.O.D.S. has been tested and proven in both laboratory situations and in the field. This paper describes some of the methods that are now being used to measure deflections in bridges. Then, a description of the development and application of the L.O.D.S. unit is given.

  6. [Leak monitoring in noninvasive ventilation].

    PubMed

    Rabec, C A; Reybet-Degat, O; Bonniaud, P; Fanton, A; Camus, P

    2004-11-01

    Nasal mask ventilation has been shown to be effective, but outcomes do not always match expectations because of mouth leaks, patient-ventilator asynchrony, or decreased upper airway patency. These developments are detected when they lead ultimately to circuit leaks that lower the effectiveness of ventilation through pressure loss, poor inspiratory triggering, and prolonged inspiratory time. The quality of sleep is affected, and adverse effects and treatment intolerance may arise. A number of ways to detect leaks and their practical consequences are proposed in this article. We applied 310 leak-detection procedures to 177 patients who had disappointing clinical, gasometric, or polysomnographic outcomes of ventilation. The leak-detection procedures varied according to the type of ventilation and the supposed underlying pathophysiological mechanism. Significant leaks were detected in 132 patients (76%); therapeutic changes were then prescribed to optimize outcomes. We present a practical method to apply in patients with suboptimal ventilation outcomes. If leaks can be detected during treatment, the probable cause of treatment failure can sometimes be established and possible pathophysiological mechanisms better understood. With this knowledge, it may be possible to improve ventilation.

  7. Ventilator Associated Pneumonia in Children.

    PubMed

    Chang, Ivy; Schibler, Andreas

    2016-09-01

    Ventilator associated pneumonia (VAP) is a common complication in mechanically ventilated children and adults. There remains much controversy in the literature over the definition, treatment and prevention of VAP. The incidence of VAP is variable, depending on the definition used and can effect up to 12% of ventilated children. For the prevention and reduction of the incidence of VAP, ventilation care bundles are suggested, which include vigorous hand hygiene, head elevation and use of non-invasive ventilation strategies. Diagnosis is mainly based on the clinical presentation with a lung infection occurring after 48hours of mechanical ventilation requiring a change in ventilator settings (mainly increased oxygen requirement, a positive culture of a specimen taken preferentially using a sterile sampling technique either using a bronchoscope or a blind lavage of the airways). A new infiltrate on a chest X ray supports the diagnosis of VAP. For the treatment of VAP, initial broad-spectrum antibiotics should be used followed by a specific antibiotic therapy with a narrow target once the bacterium is confirmed.

  8. An automated and standardized neural index to quantify patient-ventilator interaction

    PubMed Central

    2013-01-01

    Introduction The aim of this study was to validate an automated, objective and standardized algorithm for quantifying and displaying patient-ventilator interaction. Methods Using a new method to detect patient-ventilator synchrony, the present study re-analyzed previously acquired and published data from 24 mechanically ventilated adult patients (Colombo et al., Crit Care Med. 2011 Nov;39(11):2452–7). Patient-ventilator interactions were evaluated by comparing ventilator pressure and diaphragm electrical activity (EAdi) waveforms, recorded during pressure support ventilation. The EAdi and ventilator pressure waveforms were analyzed for their timings (manually and automatically determined), and the error between the two waveforms was quantified. A new index of patient-ventilator interaction (NeuroSync index), which is standardized and automated, was validated and compared to manual analysis and previously published indices of asynchrony. Results The comparison of manual and automated detection methods produced high test-retest and inter-rater reliability (Intraclass correlation coefficient = 0.95). The NeuroSync index increased the sensitivity of detecting dyssynchronies, compared to previously published indices, which were found to only detect asynchronies. Conclusion The present study introduces an automated method and the NeuroSync index to determine patient-ventilator interaction with a more sensitive analysis method than those previously described. A dashboard-style of graphical display allows a rapid overview of patient-ventilator interaction and breathing pattern at the bedside. PMID:24131701

  9. Subsurface Ventilation System Description Document

    SciTech Connect

    Eric Loros

    2001-07-25

    The Subsurface Ventilation System supports the construction and operation of the subsurface repository by providing air for personnel and equipment and temperature control for the underground areas. Although the system is located underground, some equipment and features may be housed or located above ground. The system ventilates the underground by providing ambient air from the surface throughout the subsurface development and emplacement areas. The system provides fresh air for a safe work environment and supports potential retrieval operations by ventilating and cooling emplacement drifts. The system maintains compliance within the limits established for approved air quality standards. The system maintains separate ventilation between the development and waste emplacement areas. The system shall remove a portion of the heat generated by the waste packages during preclosure to support thermal goals. The system provides temperature control by reducing drift temperature to support potential retrieval operations. The ventilation system has the capability to ventilate selected drifts during emplacement and retrieval operations. The Subsurface Facility System is the main interface with the Subsurface Ventilation System. The location of the ducting, seals, filters, fans, emplacement doors, regulators, and electronic controls are within the envelope created by the Ground Control System in the Subsurface Facility System. The Subsurface Ventilation System also interfaces with the Subsurface Electrical System for power, the Monitored Geologic Repository Operations Monitoring and Control System to ensure proper and safe operation, the Safeguards and Security System for access to the emplacement drifts, the Subsurface Fire Protection System for fire safety, the Emplacement Drift System for repository performance, and the Backfill Emplacement and Subsurface Excavation Systems to support ventilation needs.

  10. Subsurface Ventilation System Description Document

    SciTech Connect

    2000-10-12

    The Subsurface Ventilation System supports the construction and operation of the subsurface repository by providing air for personnel and equipment and temperature control for the underground areas. Although the system is located underground, some equipment and features may be housed or located above ground. The system ventilates the underground by providing ambient air from the surface throughout the subsurface development and emplacement areas. The system provides fresh air for a safe work environment and supports potential retrieval operations by ventilating and cooling emplacement drifts. The system maintains compliance within the limits established for approved air quality standards. The system maintains separate ventilation between the development and waste emplacement areas. The system shall remove a portion of the heat generated by the waste packages during preclosure to support thermal goals. The system provides temperature control by reducing drift temperature to support potential retrieval operations. The ventilation system has the capability to ventilate selected drifts during emplacement and retrieval operations. The Subsurface Facility System is the main interface with the Subsurface Ventilation System. The location of the ducting, seals, filters, fans, emplacement doors, regulators, and electronic controls are within the envelope created by the Ground Control System in the Subsurface Facility System. The Subsurface Ventilation System also interfaces with the Subsurface Electrical System for power, the Monitored Geologic Repository Operations Monitoring and Control System to ensure proper and safe operation, the Safeguards and Security System for access to the emplacement drifts, the Subsurface Fire Protection System for fire safety, the Emplacement Drift System for repository performance, and the Backfill Emplacement and Subsurface Excavation Systems to support ventilation needs.

  11. A process evaluation of the WHiTE Two trial comparing total hip artroplasty with and without dual mobility component in the treatment of displaced intracapsular fractures of the proximal femur

    PubMed Central

    Huxley, C.; Achten, J.; Costa, M. L.; Griffiths, F.

    2016-01-01

    Objectives The annual incidence of hip fracture is 620 000 in the European Union. The cost of this clinical problem has been estimated at 1.75 million disability-adjusted life years lost, equating to 1.4% of the total healthcare burden in established market economies. Recent guidance from The National Institute for Health and Clinical Excellence (NICE) states that research into the clinical and cost effectiveness of total hip arthroplasty (THA) as a treatment for hip fracture is a priority. We asked the question: can a trial investigating THA for hip fracture currently be delivered in the NHS? Methods We performed a contemporaneous process evaluation that provides a context for the interpretation of the findings of WHiTE Two – a randomised study of THA for hip fracture. We developed a mixed methods approach to situate the trial centre within the context of wider United Kingdom clinical practice. We focused on fidelity, implementation, acceptability and feasibility of both the trial processes and interventions to stakeholder groups, such as healthcare providers and patients. Results We have shown that patients are willing to participate in this type of research and that surgeons value being part of a team that has a strong research ethos. However, surgical practice does not currently reflect NICE guidance. Current models of service delivery for hip fractures are unlikely to be able to provide timely total hip arthroplasty for suitable patients. Conclusions Further observational research should be conducted to define the population of interest before future interventional studies are performed. Cite this article: C. Huxley, J. Achten, M. L. Costa, F. Griffiths, X. L. Griffin. A process evaluation of the WHiTE Two trial comparing total hip artroplasty with and without dual mobility component in the treatment of displaced intracapsular fractures of the proximal femur: Can a trial investigating total hip arthroplasty for hip fracture be delivered in the NHS? Bone

  12. Use of the virtual ventilator, a screen-based computer simulation, to teach the principles of mechanical ventilation.

    PubMed

    Keegan, Robert; Henderson, Tom; Brown, Gary

    2009-01-01

    Examination scores from 109 students enrolled in the professional veterinary program at Washington State University were evaluated to determine the effectiveness and utility of the Virtual Ventilator computer simulation for teaching the principles of mechanical ventilation in an anesthesia course. Students were randomly assigned to either a live-animal mechanical ventilation laboratory (LIVE-1st) or a computer laboratory using the mechanical ventilation simulation (SIM-1st) in week 1. During week 2, students in the LIVE-1st group participated in the ventilation simulation while students in the SIM-1st group participated in the live-animal laboratory. Student knowledge was evaluated using two similar written quizzes administered following each laboratory. Student opinions concerning the value of the simulation were assessed using an online survey. Differences in quiz scores within and between groups were compared using t-tests while survey results were tabulated. A p value of less than 0.05 was considered significant. Within the LIVE-1st group, scores for the second quiz, which was taken after the students had completed the simulation exercise, were significantly higher than those obtained from the first quiz. Accordingly, the Virtual Ventilator simulation was at least equivalent to the live-animal laboratory in the ability to present information that was subsequently tested for on the quizzes. Students in the SIM-1st group reported that use of the simulation prior to a live-animal ventilation laboratory enhanced their understanding of and ability to provide mechanical ventilation to anesthetized patients. The Virtual Ventilator simulation appears to be a useful and well-received teaching tool.

  13. 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.

  14. Liquid ventilation: a future modality?

    PubMed

    Bresnahan, M

    1999-09-01

    Liquid ventilation, an idea currently being trialled in the United States, is increasingly being discussed as a possible future trend in ventilation. A review of the available literature indicates that this treatment provides effective gas exchange and has a number of potential advantages. These include lower airway pressures, decreased alveolar surface tension, alveolar recruitment and removal of pulmonary exudate. While yet to be seen in this country, liquid ventilation may be introduced in the future. If it is, those caring for patients treated in that way will require knowledge of the mechanics and physiological changes involved, as well as the potential hazards of this modality.

  15. 6. VIEW LOOKING SOUTHEAST AT VENTILATION EQUIPMENT IN SOUTH VENTILATION ...

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

    6. VIEW LOOKING SOUTHEAST AT VENTILATION EQUIPMENT IN SOUTH VENTILATION HOUSE. THIS AIR CONDITIONING SYSTEM WAS INSTALLED BY PARKS-CRAMER COMPANY OF FITCHBURG, MASSACHUSETTS WHEN THE MILL WAS CONSTRUCTED IN 1923-24. ONE AIR WASHER AND FAN ROOM EXTERIOR IS VISIBLE ON THE RIGHT. THE DUCTS FROM BOTH FAN ROOMS (CURVED METAL STRUCTURES AT CENTER AND LEFT OF PHOTO) ARE CONNECTED TO A COMMON AIR SHAFT. - Stark Mill, 117 Corinth Road, Hogansville, Troup County, GA

  16. Sedation in mechanically ventilated patients—time to stay awake?

    PubMed Central

    Moreira, Fabio Tanzillo

    2016-01-01

    On June, 2016, Klompas and colleagues published an article in the Chest entitled “Associations between different sedatives and ventilator-associated events, length of stay, and mortality in patients who were mechanically ventilated”, which investigated the effects of different sedatives on ventilator-associated events (VAEs), length of stay, and mortality in patients who were mechanically ventilated. This study used data of over 9,603 patients in order to investigate patients over the age of 18 who underwent mechanical ventilation for more than 3 days over a 7-year period in a large academic medical center. The investigators found that propofol and dexmedetomidine were associated with less time to extubation compared with benzodiazepines, but dexmedetomidine was also associated with less time to extubation vs. propofol. This study raises important questions about the sedation of critically ill patients. PMID:27826584

  17. MEASUREMENT OF FRICTIONAL PRESSURE DIFFERENTIALS DURING A VENTILATION SURVEY

    SciTech Connect

    B.S. Prosser, PE; I.M. Loomis, PE, PhD

    2003-11-03

    During the course of a ventilation survey, both airflow quantity and frictional pressure losses are measured and quantified. The measurement of airflow has been extensively studied as the vast majority of ventilation standards/regulations are tied to airflow quantity or velocity. However, during the conduct of a ventilation survey, measurement of airflow only represents half of the necessary parameters required to directly calculate the airway resistance. The measurement of frictional pressure loss is an often misunderstood and misapplied part of the ventilation survey. This paper compares the two basic methods of frictional pressure drop measurements; the barometer and the gauge and tube. Personal experiences with each method will be detailed along with the authors' opinions regarding the applicability and conditions favoring each method.

  18. Displacement, Substitution, Sublimation: A Bibliography.

    ERIC Educational Resources Information Center

    Pedrini, D. T.; Pedrini, Bonnie C.

    Sigmund Freund worked with the mechanisms of displacement, substitution, and sublimation. These mechanisms have many similarities and have been studied diagnostically and therapeutically. Displacement and substitution seem to fit in well with phobias, hysterias, somatiyations, prejudices, and scapegoating. Phobias, prejudices, and scapegoating…

  19. Displaced Homemakers Project. Leader's Guide.

    ERIC Educational Resources Information Center

    Musickant, Claire

    This handbook is designed to assist vocational technical adult education providers in developing workshops for displaced homemakers. Covered first are various aspects of planning a displaced homemakers workshop, including format, time, location, publicity and recruitment, staff and presenters, community resources, budget items, and other…

  20. Preoperational test report, vent building ventilation system

    SciTech Connect

    Clifton, F.T.

    1997-11-04

    This represents a preoperational test report for Vent Building Ventilation Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides Heating, Ventilation, and Air Conditioning (HVAC) for the W-030 Ventilation Building. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  1. 30 CFR 57.8520 - Ventilation plan.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Ventilation plan. 57.8520 Section 57.8520... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Ventilation Underground Only § 57.8520 Ventilation plan. A plan of the mine ventilation system shall be set out by...

  2. 24 CFR 3285.505 - Crawlspace ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 5 2011-04-01 2011-04-01 false Crawlspace ventilation. 3285.505... ventilation. (a) A crawlspace with skirting must be provided with ventilation openings. The minimum net area of ventilation openings must not be less than one square foot (ft.2) for every 150 square feet...

  3. 24 CFR 3285.505 - Crawlspace ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 5 2014-04-01 2014-04-01 false Crawlspace ventilation. 3285.505... ventilation. (a) A crawlspace with skirting must be provided with ventilation openings. The minimum net area of ventilation openings must not be less than one square foot (ft.2) for every 150 square feet...

  4. 30 CFR 57.8520 - Ventilation plan.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Ventilation plan. 57.8520 Section 57.8520... Underground Only § 57.8520 Ventilation plan. A plan of the mine ventilation system shall be set out by the... ventilation plan or revisions thereto shall be submitted to the District Manager for review and comments...

  5. 30 CFR 57.8520 - Ventilation plan.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Ventilation plan. 57.8520 Section 57.8520... Underground Only § 57.8520 Ventilation plan. A plan of the mine ventilation system shall be set out by the... ventilation plan or revisions thereto shall be submitted to the District Manager for review and comments...

  6. Preoperational test, vent building ventilation system

    SciTech Connect

    Clifton, F.T., Westinghouse Hanford

    1996-08-20

    Preoperational Test Procedure for Vent Building Ventilation System, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The Vent Building ventilation system provides ventilation, heating, cooling, and zone confinement control for the W-030 Project Vent Building. The tests verify correct System operation and correct indications displayed by the central Monitor and Control system.

  7. 46 CFR 168.15-50 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Ventilation. 168.15-50 Section 168.15-50 Shipping COAST... Accommodations § 168.15-50 Ventilation. (a) All quarters must be adequately ventilated in a manner suitable to the purpose of the space and route of the vessel. (b) When mechanical ventilation is provided...

  8. 46 CFR 194.20-5 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Ventilation. 194.20-5 Section 194.20-5 Shipping COAST... 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...

  9. 33 CFR 175.201 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Ventilation. 175.201 Section 175... SAFETY EQUIPMENT REQUIREMENTS Ventilation § 175.201 Ventilation. No person may operate a boat built after... unless it is equipped with an operable ventilation system that meets the requirements of 33 CFR...

  10. 33 CFR 175.201 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Ventilation. 175.201 Section 175... SAFETY EQUIPMENT REQUIREMENTS Ventilation § 175.201 Ventilation. No person may operate a boat built after... unless it is equipped with an operable ventilation system that meets the requirements of 33 CFR...

  11. 24 CFR 3285.505 - Crawlspace ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 5 2013-04-01 2013-04-01 false Crawlspace ventilation. 3285.505... ventilation. (a) A crawlspace with skirting must be provided with ventilation openings. The minimum net area of ventilation openings must not be less than one square foot (ft.2) for every 150 square feet...

  12. 33 CFR 175.201 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Ventilation. 175.201 Section 175... SAFETY EQUIPMENT REQUIREMENTS Ventilation § 175.201 Ventilation. No person may operate a boat built after... unless it is equipped with an operable ventilation system that meets the requirements of 33 CFR...

  13. 46 CFR 168.15-50 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Ventilation. 168.15-50 Section 168.15-50 Shipping COAST... Accommodations § 168.15-50 Ventilation. (a) All quarters must be adequately ventilated in a manner suitable to the purpose of the space and route of the vessel. (b) When mechanical ventilation is provided...

  14. 46 CFR 194.20-5 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Ventilation. 194.20-5 Section 194.20-5 Shipping COAST... 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...

  15. 46 CFR 168.15-50 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Accommodations § 168.15-50 Ventilation. (a) All quarters must be adequately ventilated in a manner suitable to the purpose of the space and route of the vessel. (b) When mechanical ventilation is provided for... 46 Shipping 7 2010-10-01 2010-10-01 false Ventilation. 168.15-50 Section 168.15-50 Shipping...

  16. Physiological Effects of Positive Pressure Ventilation.

    DTIC Science & Technology

    1992-05-01

    in the ventilated patient and increase proportionally with the length of time Ventilation 43 mechanical ventilation is employed. Major infection ... sources are contributed to repeated breaks in the ventilator circuit and aspiration of gastric contents. There appears to be a positive correlation with

  17. The water penetration of different ventilation tubes.

    PubMed

    Ricks, Rupert G; Easto, Rachel; Reddy, Venkat M

    2016-10-01

    The insertion of middle ear ventilation tubes remains one of the most common procedures for ENT surgeons. A common concern amongst patients undergoing such procedures is the effect on their ability to partake in swimming and other water sports. Currently there is little evidence comparing the penetration ability of different water solutions encountered by swimmers. This study compares the water penetration of four different water solutions for Shah, mini-Shah, T tube and titanium bobbin ventilation tubes. A model was constructed to replicate a grommet inserted through a tympanic membrane using a syringe barrel, latex membrane and one of the ventilation tubes. Four solutions (sea water, chlorinated water, freshwater and soapy water) were then pipetted down the barrel until penetration of the tube occurred. The volume required for penetration was recorded. For all tubes soapy water was the most penetrating, followed by seawater. Titanium bobbins required significantly less of each solution for penetration. Mini-Shah grommets required significantly more of all solutions except soapy water for penetration to occur. Shah grommets were more resistant to chlorinated and sea water than T tubes. Mini-Shah grommets appear to protect against water penetration into the middle ear cleft and their use should be considered in patients who are keen water-sport enthusiasts. Furthermore, swimmers in sea or chlorinated water seem to be at higher risk than freshwater swimmers. Titanium bobbins were relatively easily penetrated by all four solutions and should be avoided in keen swimmers.

  18. Power turbine ventilation system

    NASA Technical Reports Server (NTRS)

    Wakeman, Thomas G. (Inventor); Brown, Richard W. (Inventor)

    1991-01-01

    Air control mechanism within a power turbine section of a gas turbine engine. The power turbine section includes a rotor and at least one variable pitch propulsor blade. The propulsor blade is coupled to and extends radially outwardly of the rotor. A first annular fairing is rotatable with the propulsor blade and interposed between the propulsor blade and the rotor. A second fairing is located longitudinally adjacent to the first fairing. The first fairing and the second fairing are differentially rotatable. The air control mechanism includes a platform fixedly coupled to a radially inner end of the propulsor blade. The platform is generally positioned in a first opening and a first fairing. The platform and the first fairing define an outer space. In a first position corresponding with a first propulsor blade pitch, the platform is substantially conformal with the first fairing. In a second position corresponding with the second propulsor blade pitch, an edge portion of the platform is displaced radially outwardly from the first fairing. When the blades are in the second position and rotating about the engine axis, the displacement of the edge portion with respect to the first fairing allows air to flow from the outer space to the annular cavity.

  19. Mechanical ventilation and lung infection in the genesis of air-space enlargement

    PubMed Central

    Sartorius, Alfonso; Lu, Qin; Vieira, Silvia; Tonnellier, Marc; Lenaour, Gilles; Goldstein, Ivan; Rouby, Jean-Jacques

    2007-01-01

    Introduction Air-space enlargement may result from mechanical ventilation and/or lung infection. The aim of this study was to assess how mechanical ventilation and lung infection influence the genesis of bronchiolar and alveolar distention. Methods Four groups of piglets were studied: non-ventilated-non-inoculated (controls, n = 5), non-ventilated-inoculated (n = 6), ventilated-non-inoculated (n = 6), and ventilated-inoculated (n = 8) piglets. The respiratory tract of intubated piglets was inoculated with a highly concentrated solution of Escherichia coli. Mechanical ventilation was maintained during 60 hours with a tidal volume of 15 ml/kg and zero positive end-expiratory pressure. After sacrifice by exsanguination, lungs were fixed for histological and lung morphometry analyses. Results Lung infection was present in all inoculated piglets and in five of the six ventilated-non-inoculated piglets. Mean alveolar and mean bronchiolar areas, measured using an analyzer computer system connected through a high-resolution color camera to an optical microscope, were significantly increased in non-ventilated-inoculated animals (+16% and +11%, respectively, compared to controls), in ventilated-non-inoculated animals (+49% and +49%, respectively, compared to controls), and in ventilated-inoculated animals (+95% and +118%, respectively, compared to controls). Mean alveolar and mean bronchiolar areas significantly correlated with the extension of lung infection (R = 0.50, p < 0.01 and R = 0.67, p < 0.001, respectively). Conclusion Lung infection induces bronchiolar and alveolar distention. Mechanical ventilation induces secondary lung infection and is associated with further air-space enlargement. The combination of primary lung infection and mechanical ventilation markedly increases air-space enlargement, the degree of which depends on the severity and extension of lung infection. PMID:17274806

  20. 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.

  1. Mitochondria-targeted antioxidants protect against mechanical ventilation-induced diaphragm weakness.

    PubMed

    Powers, Scott K; Hudson, Matthew B; Nelson, W Bradley; Talbert, Erin E; Min, Kisuk; Szeto, Hazel H; Kavazis, Andreas N; Smuder, Ashley J

    2011-07-01

    Mechanical ventilation is a life-saving intervention used to provide adequate pulmonary ventilation in patients suffering from respiratory failure. However, prolonged mechanical ventilation is associated with significant diaphragmatic weakness resulting from both myofiber atrophy and contractile dysfunction. Although several signaling pathways contribute to diaphragm weakness during mechanical ventilation, it is established that oxidative stress is required for diaphragmatic weakness to occur. Therefore, identifying the site(s) of mechanical ventilation- induced reactive oxygen species production in the diaphragm is important. These experiments tested the hypothesis that elevated mitochondrial reactive oxygen species emission is required for mechanical ventilation-induced oxidative stress, atrophy, and contractile dysfunction in the diaphragm. Cause and effect was determined by preventing mechanical ventilation-induced mitochondrial reactive oxygen species emission in the diaphragm of rats using a novel mitochondria-targeted antioxidant (SS-31). None. Compared to mechanically ventilated animals treated with saline, animals treated with SS-31 were protected against mechanical ventilation-induced mitochondrial dysfunction, oxidative stress, and protease activation in the diaphragm. Importantly, treatment of animals with the mitochondrial antioxidant also protected the diaphragm against mechanical ventilation-induced myofiber atrophy and contractile dysfunction. These results reveal that prevention of mechanical ventilation-induced increases in diaphragmatic mitochondrial reactive oxygen species emission protects the diaphragm from mechanical ventilation-induced diaphragmatic weakness. This important new finding indicates that mitochondria are a primary source of reactive oxygen species production in the diaphragm during prolonged mechanical ventilation. These results could lead to the development of a therapeutic intervention to impede mechanical ventilation

  2. [Clinical significance of dynamic pressure-volume curve in neonatal mechanical ventilation].

    PubMed

    Zhu, Yuan-Peng; Ma, Li-Ya; Wu, Zhi-Jun; Lu, Guang-Jin; Han, Yu-Kun

    2009-07-01

    To study the characteristics and role of dynamic pressure-volume curve (P-V curve) in neonatal mechanical ventilation. A dynamic P-V curve was automatically drawn by the Stephanie ventilator. The slope rate of dynamic P-V curve was measured in 25 neonates who received mechanical ventilation 1, 24, 48 and 72 hrs after ventilation and before weaning from ventilation. Minute-ventilation (MV), mean airway pressure (Pmean), and fraction of inspired oxygen (FiO2) were recorded. The patterns of dynamic P-V curve during abnormal ventilation (resistance to ventilator, part or complete airway obstruction, airway leaking and tracheal catheter exodus) were observed. With the improvement of pulmonary disease, the slope rate of P-V curve and MV increased, Pmean and FiO2 decreased, and the P-V curve shifted to the volume axle. The slope rate of curve 48 and 72 hrs after ventilation and before weaning from ventilation (1.05+/-0.48, 1.10+/-0.42 and 1.13+/-0.37 mL/cmH2O respectively) increased significantly compared with that 1 hr after ventilation (0.76+/-0.53 mL/cmH2O) (p<0.05 or 0.01). Abnormal ventilation led to abnormal appearance of dynamic P-V curve. The increasing slope rate of dynamic P-V curve and the curve shifting to volume axle in neonatal mechanical ventilation may be associated with the improvement of pulmonary disease. The appearance changes of the curve may be of value in the assessment of abnormal ventilation.

  3. Predictors of noninvasive ventilation failure in patients with hematologic malignancy and acute respiratory failure.

    PubMed

    Adda, Mélanie; Coquet, Isaline; Darmon, Michaël; Thiery, Guillaume; Schlemmer, Benoît; Azoulay, Elie

    2008-10-01

    The current trend to manage critically ill hematologic patients admitted with acute respiratory failure is to perform noninvasive ventilation to avoid endotracheal intubation. However, failure of noninvasive ventilation may lead to an increased mortality. Retrospective study to determine the frequency of noninvasive ventilation failure and identify its determinants. Medical intensive care unit in a University hospital. All consecutive patients with hematologic malignancies admitted to the intensive care unit over a 10-yr period who received noninvasive ventilation. A total of 99 patients were studied. Simplified Acute Physiology Score II at admission was 49 (median, interquartile range, 39-57). Fifty-three patients (54%) failed noninvasive ventilation and required endotracheal intubation. Their PaO2/FiO2 ratio was significantly lower (175 [101-236] vs. 248 [134-337]) and their respiratory rate under noninvasive ventilation was significantly higher (32 breaths/min [30-36] vs. 28 [27-30]). Forty-seven patients (89%) who failed noninvasive ventilation required vasopressors. Hospital mortality was 79% in those who failed noninvasive ventilation, and 41% in those who succeeded. Patients who failed noninvasive ventilation had a significantly longer intensive care unit stay (13 days [8-23] vs. 5 [2-8]) and a significantly higher rate of intensive care unit-acquired infections (32% compared with 7%). Factors independently associated with noninvasive ventilation failure by multivariate analysis were respiratory rate under noninvasive ventilation, longer delay between admission and noninvasive ventilation first use, need for vasopressors or renal replacement therapy, and acute respiratory distress syndrome. Failure of noninvasive ventilation occurs in half the critically ill hematologic patients and is associated with an increased mortality. Predictors of noninvasive ventilation failure might be used to guide decisions regarding intubation.

  4. Adjustment to trauma exposure in refugee, displaced, and non-displaced Bosnian women.

    PubMed

    Schmidt, Martina; Kravic, Nera; Ehlert, Ulrike

    2008-09-01

    The war in Bosnia resulted in the displacement of millions of civilians, most of them women. Ten years after the civil war, many of them are still living as refugees in their country of origin or abroad. Research on different refugee groups has continuously reported persistent levels of posttraumatic stress disorder (PTSD) and other mental-health problems in this population. The present study compared PTSD and self-concept in Bosnian refugee women (n = 29) with women who were internally displaced (IDP; n = 26) and non-displaced women (n = 32). Data were collected using the Bosnian Trauma Questionnaire and four scales assessing self-esteem, perceived incompetence, externality of control attribution, and persistence. IDPs scored significantly higher on PTSD symptoms, externality of control attribution and perceived incompetence, and lower on self-esteem than both refugee and non-displaced women. The level of education most strongly predicted PTSD symptom severity, followed by the type of displacement, and exposure to violence during the war. Associations of self-concept with displacement and psychopathology were inconsistent, with type of displacement predicting control attributions but not other aspects of self-concept and PTSD symptoms being partly related to perceived incompetence and self-esteem. These results support previous findings stating that, in the long run, refugees show better mental health than IDPs, and that witnessing violence is a traumatic experience strongly linked to the development of PTSD symptoms. Results further indicate that education plays an important role in the development of PTSD symptoms. Associations of control attributions and type of displacement were found; these results have not been previously documented in literature.

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

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Power ventilation systems except machinery space ventilation systems. 111.103-1 Section 111.103-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... Power ventilation systems except machinery space ventilation systems. Each power ventilation system...

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

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Power ventilation systems except machinery space ventilation systems. 111.103-1 Section 111.103-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... Power ventilation systems except machinery space ventilation systems. Each power ventilation system...

  7. Study on the Evaluation Method for Fault Displacement: Probabilistic Approach Based on Japanese Earthquake Rupture Data - Principal fault displacements -

    NASA Astrophysics Data System (ADS)

    Kitada, N.; Inoue, N.; Tonagi, M.

    2016-12-01

    The purpose of Probabilistic Fault Displacement Hazard Analysis (PFDHA) is estimate fault displacement values and its extent of the impact. There are two types of fault displacement related to the earthquake fault: principal fault displacement and distributed fault displacement. Distributed fault displacement should be evaluated in important facilities, such as Nuclear Installations. PFDHA estimates principal fault and distributed fault displacement. For estimation, PFDHA uses distance-displacement functions, which are constructed from field measurement data. We constructed slip distance relation of principal fault displacement based on Japanese strike and reverse slip earthquakes in order to apply to Japan area that of subduction field. However, observed displacement data are sparse, especially reverse faults. Takao et al. (2013) tried to estimate the relation using all type fault systems (reverse fault and strike slip fault). After Takao et al. (2013), several inland earthquakes were occurred in Japan, so in this time, we try to estimate distance-displacement functions each strike slip fault type and reverse fault type especially add new fault displacement data set. To normalized slip function data, several criteria were provided by several researchers. We normalized principal fault displacement data based on several methods and compared slip-distance functions. The normalized by total length of Japanese reverse fault data did not show particular trend slip distance relation. In the case of segmented data, the slip-distance relationship indicated similar trend as strike slip faults. We will also discuss the relation between principal fault displacement distributions with source fault character. According to slip distribution function (Petersen et al., 2011), strike slip fault type shows the ratio of normalized displacement are decreased toward to the edge of fault. However, the data set of Japanese strike slip fault data not so decrease in the end of the fault

  8. Strain-Based Displacement Estimation For Precision Spacecraft Structures

    DTIC Science & Technology

    2005-12-01

    Model , Bragg gratings 15. NUMBER OF PAGES 49 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18. SECURITY CLASSIFICATION OF...deflection at successive nodes was computed and compared to a Nastran simulation of the truss displacements. vi...Experimental Implementation ........10 C. BUILDING THE ANALYTICAL MODEL .....................13 III. STRAIN-DISPLACEMENT MAPPING

  9. Displacement Damage in Bipolar Linear Integrated Circuits

    NASA Technical Reports Server (NTRS)

    Rax, B. G.; Johnston, A. H.; Miyahira, T.

    2000-01-01

    Although many different processes can be used to manufacture linear integrated circuits, the process that is used for most circuits is optimized for high voltage -- a total power supply voltage of about 40 V -- and low cost. This process, which has changed little during the last twenty years, uses lateral and substrate p-n-p transistors. These p-n-p transistors have very wide base regions, increasing their sensitivity to displacement damage from electrons and protons. Although displacement damage effects can be easily treated for individual transistors, the net effect on linear circuits can be far more complex because circuit operation often depends on the interaction of several internal transistors. Note also that some circuits are made with more advanced processes with much narrower base widths. Devices fabricated with these newer processes are not expected to be significantly affected by displacement damage for proton fluences below 1 x 10(exp 12) p/sq cm. This paper discusses displacement damage in linear integrated circuits with more complex failure modes than those exhibited by simpler devices, such as the LM111 comparator, where the dominant response mode is gain degradation of the input transistor. Some circuits fail catastrophically at much lower equivalent total dose levels compared to tests with gamma rays. The device works satisfactorily up to nearly 1 Mrad(Si) when it is irradiated with gamma rays, but fails catastrophically between 50 and 70 krad(Si) when it is irradiated with protons.

  10. Music interventions for mechanically ventilated patients.

    PubMed

    Bradt, Joke; Dileo, Cheryl; Grocke, Denise

    2010-12-08

    Mechanical ventilation often causes major distress and anxiety in patients. Music interventions have been used to reduce anxiety and distress and improve physiological functioning in medical patients; however its efficacy for mechanically ventilated patients needs to be evaluated. To examine the effects of music interventions with standard care versus standard care alone on anxiety and physiological responses in mechanically ventilated patients. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 1), MEDLINE, CINAHL, AMED, EMBASE, PsycINFO, LILACS, Science Citation Index, www.musictherapyworld.net, CAIRSS for Music, Proquest Digital Dissertations, ClinicalTrials.gov, Current Controlled Trials, the National Research Register, and NIH CRISP (all to January 2010). We handsearched music therapy journals and reference lists and contacted relevant experts to identify unpublished manuscripts. There was no language restriction. We included all randomized and quasi-randomized controlled trials that compared music interventions and standard care with standard care alone for mechanically ventilated patients. Two authors independently extracted the data and assessed the methodological quality. Additional information was sought from the trial researchers, when necessary. Results were presented using mean differences for outcomes measured by the same scale and standardized mean differences for outcomes measured by different scales. Post-test scores were used. In cases of significant baseline difference, we used change scores. We included eight trials (213 participants). Music listening was the main intervention used, and seven of the studies did not include a trained music therapist. Results indicated that music listening may be beneficial for anxiety reduction in mechanically ventilated patients; however, these results need to be interpreted with caution due to the small sample size. Findings indicated that listening to

  11. Equivalence in Ventilation and Indoor Air Quality

    SciTech Connect

    Sherman, Max; Walker, Iain; Logue, Jennifer

    2011-08-01

    We ventilate buildings to provide acceptable indoor air quality (IAQ). Ventilation standards (such as American Society of Heating, Refrigerating, and Air-Conditioning Enginners [ASHRAE] Standard 62) specify minimum ventilation rates without taking into account the impact of those rates on IAQ. Innovative ventilation management is often a desirable element of reducing energy consumption or improving IAQ or comfort. Variable ventilation is one innovative strategy. To use variable ventilation in a way that meets standards, it is necessary to have a method for determining equivalence in terms of either ventilation or indoor air quality. This study develops methods to calculate either equivalent ventilation or equivalent IAQ. We demonstrate that equivalent ventilation can be used as the basis for dynamic ventilation control, reducing peak load and infiltration of outdoor contaminants. We also show that equivalent IAQ could allow some contaminants to exceed current standards if other contaminants are more stringently controlled.

  12. Basic concepts in mechanical ventilation.

    PubMed

    Carbery, Catherine

    2008-03-01

    Mechanical ventilatory support is a major component of the clinical management of critically ill patients admitted into intensive care. Closely linked with the developments within critical care medicine, the use of ventilatory support has been increasing since the polio epidemics in the 1950s (Lassen 1953). Initially used to provide controlled mandatory ventilation, today with advances in technology, most mechanical ventilators are triggered by the patient, increasing the awareness of the complexity of patient/ventilator interaction (Tobin 1994). Though ventilator appearance and design may have changed quite significantly and the variety of options for support extensive, the basic concepts of mechanical ventilatory support of the critically ill patient remains unchanged. This paper aims to outline these concepts so as to gain a better understanding of mechanical ventilatory support.

  13. Mechanical ventilation in the home.

    PubMed

    Make, B J; Gilmartin, M E

    1990-07-01

    Despite advances in the application of mechanical ventilation as a short-term, life-saving technique, intensive care units are increasingly faced with patients who cannot be weaned from ventilatory assistance and who require mechanical ventilation as a long-term, life-supporting necessity. Because of limited resources in health care facilities for the management of chronic ventilator-assisted individuals, home care has become an important option. With careful selection of appropriate candidates, home care for ventilator-assisted individuals can result in not only decreased respiratory symptoms, reduction in hospitalization, and improved physiologic measures, but also an improved quality of life with substantial survival and a reduction in the costs of medical care.

  14. Tracheostomy under jet-ventilation--an alternative approach to ventilating patients undergoing surgically created or percutaneous dilational tracheostomy.

    PubMed

    Abdulla, Walied; Netter, Ute; Abdulla, Susanne; Isaak, Igor

    2008-02-01

    In a prospective observational study we compared the results of 297 elective tracheostomies under jet-ventilation with regard to its complication rate and practicability. Of those, 156 patients underwent surgically created tracheostomy (SCT) and 141 patients percutaneous dilational tracheostomy (PDT). Initially, in 159 patients jet-ventilation was performed using a jet-cannula inserted intratracheally through the cricothyroid membrane. In the remaining 138 patients the jet-ventilator was connected to the endoscopic instrument channel (2.2 mm ID, 4.9 mm OD, 600 mm Length) and ventilation via the fiberoptic bronchoscope (FB-15x, Pentax Europe GmbH, Hamburg) was applied manually. With jet-ventilation, oxygenation was maintained throughout the procedure as long as the tracheal puncture was successful und jet-cannula fixed in place. The bronchoscope-guided gas stream, when compared to jet-cannula inserted intratracheally, offered more space for tracheostomy and safety for the patient. The permanent danger of mishappenings and dislocation involved with the jet-cannula could be avoided, since the bronchoscope was operating on under direct visualization. Under these circumstances, PDT is an acceptable approach to inserting a tracheostomy tube under jet-ventilation via bronchoscope, particularly for the management of difficult airway in critically ill patients.

  15. Ventilation Model and Analysis Report

    SciTech Connect

    V. Chipman

    2003-07-18

    This model and analysis report develops, validates, and implements a conceptual model for heat transfer in and around a ventilated emplacement drift. This conceptual model includes thermal radiation between the waste package and the drift wall, convection from the waste package and drift wall surfaces into the flowing air, and conduction in the surrounding host rock. These heat transfer processes are coupled and vary both temporally and spatially, so numerical and analytical methods are used to implement the mathematical equations which describe the conceptual model. These numerical and analytical methods predict the transient response of the system, at the drift scale, in terms of spatially varying temperatures and ventilation efficiencies. The ventilation efficiency describes the effectiveness of the ventilation process in removing radionuclide decay heat from the drift environment. An alternative conceptual model is also developed which evaluates the influence of water and water vapor mass transport on the ventilation efficiency. These effects are described using analytical methods which bound the contribution of latent heat to the system, quantify the effects of varying degrees of host rock saturation (and hence host rock thermal conductivity) on the ventilation efficiency, and evaluate the effects of vapor and enhanced vapor diffusion on the host rock thermal conductivity.

  16. Regenerative rotary displacer Stirling engine

    SciTech Connect

    Isshiki, Naotsugu; Watanabe, Hiroichi; Raggi, L.; Isshiki, Seita; Hirata, Koichi

    1996-12-31

    A few rotary displacer Stirling engines in which the displacer has one gas pocket space at one side and rotates in a main enclosed cylinder, which is heated from one side and cooled from opposite side without any regenerator, have been studied for some time by the authors. The authors tried to improve this engine by equipping it with a regenerator, because without a regenerator, pressure oscillation and efficiency are too small. Here, several types of regenerative rotary displacer piston Stirling engines are proposed. One is the contra-rotating tandem two disc type displacer engine using axial heat conduction through side walls or by heat pipes and another is a single disc type with circulating fluid regenerator or heat pipes. Stirling engines of this new rotary displacer type are thought to attain high speed. Here, experimental results of the original rotary displacer Stirling engine without a regenerator, and one contra-rotating tandem displacer engine with side wall regenerator by axial heat conduction are reported accompanied with a discussion of the results.

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

    SciTech Connect

    Brennan, Douglas; Schubert, Leah; Diot, Quentin; Castillo, Richard; Castillo, Edward; Guerrero, Thomas; Martel, Mary K.; Linderman, Derek; Gaspar, Laurie E.; Miften, Moyed; Kavanagh, Brian D.; Vinogradskiy, Yevgeniy

    2015-06-01

    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 with 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

  18. Clinical validation of 4-dimensional computed tomography ventilation with pulmonary function test data.

    PubMed

    Brennan, Douglas; Schubert, Leah; Diot, Quentin; Castillo, Richard; Castillo, Edward; Guerrero, Thomas; Martel, Mary K; Linderman, Derek; Gaspar, Laurie E; Miften, Moyed; Kavanagh, Brian D; Vinogradskiy, Yevgeniy

    2015-06-01

    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. Ninety-eight lung cancer patients with 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. 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. 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

  19. Conventional gas ventilation, liquid-assisted high-frequency oscillatory ventilation, and tidal liquid ventilation in surfactant-treated preterm lambs.

    PubMed

    Degraeuwe, P L; Thunnissen, F B; Jansen, N J; Dormaar, J T; Dohmen, L R; Blanco, C E

    2000-11-01

    This study was designed to compare the efficacy and potential protective or injurious effects of tidal liquid ventilation (TLV), liquid-assisted high-frequency oscillatory ventilation (LA-HFOV), and high PEEP conventional mechanical ventilation (CMV) in neonatal respiratory distress syndrome. Preterm lambs (124-126 days gestation), prophylactically treated with natural surfactant, were allocated to one of the treatment modalities or to an untreated fetal control group (F), euthanised after tracheal ligation. LA-HFOV animals received an intratracheal loading dose of 5 mL x kg(-1) followed by a continuous intrapulmonary instillation of 12 mL x kg(-1);h(-1) FC-75 perfluorocarbon liquid. The ventilation strategies aimed at keeping clinically appropriate arterial blood gases for a study period of 5 hours. A histological lung injury score was calculated and semiquantitative morphometry was performed on lung tissue fixed by vascular perfusion. The alveolar-arterial pressure difference for O2 was significantly lower throughout the study in TLV compared to CMV lambs; at 1, 2, and 5 hours, oxygenation was better in TLV when compared to LA-HFOV. Total lung injury scores in TLV lambs were significantly lower than in either CMV or LA-HFOV animals, but higher when compared to F. CMV and LA-HFOV induced an excess of collapsed and overdistended alveoli, whereas in TLV alveolar expansion was normally distributed around predominantly normal alveoli. CMV and LA-HFOV, but not TLV, were associated with an excess of dilated airways. Thus, in the ovine neonatal RDS model, TLV compared favourably to either gas ventilation strategy by its more uniform ventilation, reduced lung injury, and improved gas exchange.

  20. Optimization of ventilator setting by flow and pressure waveforms analysis during noninvasive ventilation for acute exacerbations of COPD: a multicentric randomized controlled trial

    PubMed Central

    2011-01-01

    Introduction The analysis of flow and pressure waveforms generated by ventilators can be useful in the optimization of patient-ventilator interactions, notably in chronic obstructive pulmonary disease (COPD) patients. To date, however, a real clinical benefit of this approach has not been proven. Methods The aim of the present randomized, multi-centric, controlled study was to compare optimized ventilation, driven by the analysis of flow and pressure waveforms, to standard ventilation (same physician, same initial ventilator setting, same time spent at the bedside while the ventilator screen was obscured with numerical data always available). The primary aim was the rate of pH normalization at two hours, while secondary aims were changes in PaCO2, respiratory rate and the patient's tolerance to ventilation (all parameters evaluated at baseline, 30, 120, 360 minutes and 24 hours after the beginning of ventilation). Seventy patients (35 for each group) with acute exacerbation of COPD were enrolled. Results Optimized ventilation led to a more rapid normalization of pH at two hours (51 vs. 26% of patients), to a significant improvement of the patient's tolerance to ventilation at two hours, and to a higher decrease of PaCO2 at two and six hours. Optimized ventilation induced physicians to use higher levels of external positive end-expiratory pressure, more sensitive inspiratory triggers and a faster speed of pressurization. Conclusions The analysis of the waveforms generated by ventilators has a significant positive effect on physiological and patient-centered outcomes during acute exacerbation of COPD. The acquisition of specific skills in this field should be encouraged. Trial registration ClinicalTrials.gov NCT01291303. PMID:22115190

  1. Evaluation of the ΔV 4D CT ventilation calculation method using in vivo xenon CT ventilation data and comparison to other methods.

    PubMed

    Zhang, Geoffrey G; Latifi, Kujtim; Du, Kaifang; Reinhardt, Joseph M; Christensen, Gary E; Ding, Kai; Feygelman, Vladimir; Moros, Eduardo G

    2016-03-08

    Ventilation distribution calculation using 4D CT has shown promising potential in several clinical applications. This study evaluated the direct geometric ventilation calculation method, namely the ΔV method, with xenon-enhanced CT (XeCT) ventilation data from four sheep, and compared it with two other published meth-ods, the Jacobian and the Hounsfield unit (HU) methods. Spearman correlation coefficient (SCC) and Dice similarity coefficient (DSC) were used for the evaluation and comparison. The average SCC with one standard deviation was 0.44 ± 0.13 with a range between 0.29 and 0.61 between the XeCT and ΔV ventilation distributions. The average DSC value for lower 30% ventilation volumes between the XeCT and ΔV ventilation distributions was 0.55 ± 0.07 with a range between 0.48 and 0.63. Ventilation difference introduced by deformable image registration errors improved with smoothing. In conclusion, ventilation distributions generated using ΔV-4D CT and deformable image registration are in reasonably agreement with the in vivo XeCT measured ventilation distribution.

  2. 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

  3. Fiber-optic couplers as displacement sensors

    NASA Astrophysics Data System (ADS)

    Baruch, Martin C.; Gerdt, David W.; Adkins, Charles M.

    2003-04-01

    We introduce the novel concept of using a fiber-optic coupler as a versatile displacement sensor. Comparatively long fiber-optic couplers, with a coupling region of approximately 10 mm, are manufactured using standard communication SM fiber and placed in a looped-back configuration. The result is a displacement sensor, which is robust and highly sensitive over a wide dynamic range. This displacement sensor resolves 1-2 μm over distances of 1-1.5 mm and is characterized by the essential absence of a 'spring constant' plaguing other strain gauge-type sensors. Consequently, it is possible to couple to extremely weak vibrations, such as the skin displacement affected by arterial heart beat pulsations. Used as a wrist-worn heartbeat monitor, the fidelity of the arterial pulse signal has been shown to be so high that it is possible to not only determine heartbeat and breathing rates, but to implement a new single-point blood pressure measurement scheme which does not squeeze the arm. In an application as a floor vibration sensor for the non-intrusive monitoring of independently living elderly, the sensor has been shown to resolve the distinct vibration spectra of different persons and different events.

  4. Effect of helium-oxygen (heliox) gas mixtures on the function of four pediatric ventilators.

    PubMed

    Berkenbosch, John W; Grueber, Ryan E; Dabbagh, Osuama; McKibben, Andrew W

    2003-07-01

    To evaluate the effects of helium on the function of four ventilators commonly used in pediatrics: the Bird VIP, Bird VIP Gold, Servo 300, and Servo 900C. Prospective setting. Research laboratory at a university hospital. Helium was administered as an 80:20 mixture of helium-oxygen through the air inlet of the ventilator. Delivered fraction of inspired oxygen (Fio(2)) was compared with the Fio(2) set on the blender dial. Inspiratory displayed tidal volume was recorded as an indicator of what the ventilator "believed" it had delivered and was compared with the V(T) displayed during ventilation with 100% oxygen (control). Actual delivered V(T) was measured by a Neonatal Bicore connected to the side port of a "bag-in-box" spirometer, making measurements independent of inspired gas properties, and was compared with V(T) delivered during ventilation with 100% oxygen. Five gas mixtures were evaluated: Fio(2) = 0.2, 0.4, 0.6, 0.8, and 1.0 (balance helium). Delivered Fio(2) was less than set Fio(2) on the Servo 900C and VIP ventilators. V(T) displayed was minimally altered by helium during volume-controlled ventilation but substantially decreased during pressure-controlled ventilation, particularly with the Bird ventilators. During volume-controlled ventilation, V(T) delivered was substantially increased by helium with the Bird and, to a lesser degree, the Servo 900C ventilators. In contrast, V(T) delivered decreased slightly in helium with the Servo 300. The same pattern, but with a decreased magnitude, was observed for V(T) delivered during pressure-controlled ventilation. The addition of helium has a significant effect on Fio(2) delivery, displayed inspiratory V(T), and actual delivered V(T) during both volume- and pressure-controlled ventilation in four ventilators commonly used in pediatric critical care. These effects are both ventilator specific and ventilation mode specific, mandating vigilance during helium ventilation in clinical practice.

  5. 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.

  6. Protein-water displacement distributions.

    PubMed

    Doster, Wolfgang; Settles, Marcus

    2005-06-01

    The statistical properties of fast protein-water motions are analyzed by dynamic neutron scattering experiments. Using isotopic exchange, one probes either protein or water hydrogen displacements. A moment analysis of the scattering function in the time domain yields model-independent information such as time-resolved mean square displacements and the Gauss-deviation. From the moments, one can reconstruct the displacement distribution. Hydration water displays two dynamical components, related to librational motions and anomalous diffusion along the protein surface. Rotational transitions of side chains, in particular of methyl groups, persist in the dehydrated and in the solvent-vitrified protein structure. The interaction with water induces further continuous protein motions on a small scale. Water acts as a plasticizer of displacements, which couple to functional processes such as open-closed transitions and ligand exchange.

  7. Displacement sensing system and method

    DOEpatents

    VunKannon, Jr., Robert S

    2006-08-08

    A displacement sensing system and method addresses demanding requirements for high precision sensing of displacement of a shaft, for use typically in a linear electro-dynamic machine, having low failure rates over multi-year unattended operation in hostile environments. Applications include outer space travel by spacecraft having high-temperature, sealed environments without opportunity for servicing over many years of operation. The displacement sensing system uses a three coil sensor configuration, including a reference and sense coils, to provide a pair of ratio-metric signals, which are inputted into a synchronous comparison circuit, which is synchronously processed for a resultant displacement determination. The pair of ratio-metric signals are similarly affected by environmental conditions so that the comparison circuit is able to subtract or nullify environmental conditions that would otherwise cause changes in accuracy to occur.

  8. 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 Central

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

    2014-01-01

    oxygenation index (90% sensitive, 75% specific) or less than 90% increase in Pao2/Fio2 (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 Pao2/Fio2 (91% sensitive, 89% specific) to identify nonsurvivors. Conclusions 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 Pao2/Fio224/Pao2/Fio2pre or oxygenation index24/oxygenation indexpre reliably discriminates nonsurvivors from survivors. These findings should be prospectively verified. PMID:24413319

  9. Ventilator risk management using a programmed monitor.

    PubMed

    Silvern, D A; Gupte, P M

    1989-01-01

    A computer program was written to improve quality control and risk management of patients on ventilators. The software was designed to run on the new-generation Spacelabs PC Monitor interfaced to the Puritan-Bennett 7200a ventilator. Before the program allows connection of the ventilator to a patient, the ventilator is polled for initial hardware status, alarm statuses and alarm limit settings. If there are no hardware failures, alarm violations, or improperly set alarm limits, the program prompts the clinician to connect the ventilator to the patient. Polling is done periodically after patient ventilation begins, and patient data, alarm conditions, or changes to the ventilator settings are automatically written to disk. In addition, real-time data can be displayed at any time during the ventilation session by using a set of touch-screen options. After the ventilation session is complete, the clinician can print the final report in hard copy or to disk.

  10. 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.

  11. Respiratory syncytial virus infection in children admitted to hospital but ventilated mechanically for other reasons.

    PubMed

    von Renesse, Anja; Schildgen, Oliver; Klinkenberg, Dennis; Müller, Andreas; von Moers, Arpad; Simon, Arne

    2009-01-01

    One thousand five hundred sixty-eight RSV infections were documented prospectively in 1,541 pediatric patients. Of these, 20 (1.3%) had acquired the RSV infection while treated by mechanical ventilation for reasons other than the actual RSV infection (group ventilated mechanically). The clinical characteristics of children who were infected with respiratory syncytial virus (RSV) infection while ventilated mechanically for other reasons are described and compared with a matched control group. Sixty percent of the group ventilated mechanically had at least one additional risk factor for a severe course of infection (prematurity 50%, chronic lung disease 20%, congenital heart disease 35%, immunodeficiency 20%). The median age at diagnosis in the group ventilated mechanically was 4.2 months. The matched pairs analysis (group ventilated mechanically vs. control group) revealed a higher proportion of patients with hypoxemia and apnoea in the group ventilated mechanically; more patients in the control group showed symptoms of airway obstruction (wheezing). At least one chest radiography was performed in 95% of the patients (n = 19) in the group ventilated mechanically versus 45% (n = 9) in the control group (P = 0.001). The frequency of pneumonia was 40% in the group ventilated mechanically and 20% in the control group. Despite existing consensus recommendations, only two patients (10%) of the group ventilated mechanically had received palivizumab previously. Significantly more patients in the group ventilated mechanically received antibiotic treatment (85% vs. 45%, P = 0.008), and attributable mortality was higher in the group ventilated mechanically (15% [n = 3] vs. 0% in the control group, P = 0.231). Children treated by long term mechanical ventilation may acquire RSV infection by transmission by droplets or caregivers and face an increased risk of a severe course of RSV infection. The low rate of immunoprophylaxis in this particular risk group should be improved.

  12. Lucky interferometry for displacement measurement

    NASA Astrophysics Data System (ADS)

    Ioniţă, Bogdan; Logofătu, Petre Cătălin; Apostol, Dan

    2009-11-01

    We extrapolated the lucky imaging technique, mostly used in astronomy, to the field of interferometry for displacement measurement. From the batch of interferograms generated by a Twyman-Green-type interferometer and acquired by a CCD camera, those with high overall contrast were selected and fitted to a sinusoidal function. The high-contrast interferograms showed a significantly lower dispersion and, consequently, a lower uncertainty of the measured displacement.

  13. A trial of intraoperative low-tidal-volume ventilation in abdominal surgery.

    PubMed

    Futier, Emmanuel; Constantin, Jean-Michel; Paugam-Burtz, Catherine; Pascal, Julien; Eurin, Mathilde; Neuschwander, Arthur; Marret, Emmanuel; Beaussier, Marc; Gutton, Christophe; Lefrant, Jean-Yves; Allaouchiche, Bernard; Verzilli, Daniel; Leone, Marc; De Jong, Audrey; Bazin, Jean-Etienne; Pereira, Bruno; Jaber, Samir

    2013-08-01

    Lung-protective ventilation with the use of low tidal volumes and positive end-expiratory pressure is considered best practice in the care of many critically ill patients. However, its role in anesthetized patients undergoing major surgery is not known. In this multicenter, double-blind, parallel-group trial, we randomly assigned 400 adults at intermediate to high risk of pulmonary complications after major abdominal surgery to either nonprotective mechanical ventilation or a strategy of lung-protective ventilation. The primary outcome was a composite of major pulmonary and extrapulmonary complications occurring within the first 7 days after surgery. The two intervention groups had similar characteristics at baseline. In the intention-to-treat analysis, the primary outcome occurred in 21 of 200 patients (10.5%) assigned to lung-protective ventilation, as compared with 55 of 200 (27.5%) assigned to nonprotective ventilation (relative risk, 0.40; 95% confidence interval [CI], 0.24 to 0.68; P=0.001). Over the 7-day postoperative period, 10 patients (5.0%) assigned to lung-protective ventilation required noninvasive ventilation or intubation for acute respiratory failure, as compared with 34 (17.0%) assigned to nonprotective ventilation (relative risk, 0.29; 95% CI, 0.14 to 0.61; P=0.001). The length of the hospital stay was shorter among patients receiving lung-protective ventilation than among those receiving nonprotective ventilation (mean difference, -2.45 days; 95% CI, -4.17 to -0.72; P=0.006). As compared with a practice of nonprotective mechanical ventilation, the use of a lung-protective ventilation strategy in intermediate-risk and high-risk patients undergoing major abdominal surgery was associated with improved clinical outcomes and reduced health care utilization. (IMPROVE ClinicalTrials.gov number, NCT01282996.).

  14. [Are subcortical signs in the EEG a reliable indication of brain stem displacement and impaction processes by intracranial space-occupying processes? A comparative computer tomography-electroencephalography study].

    PubMed

    Zettler, H; Järisch, M; Leonhard, T

    1985-01-01

    Within the scope of an elektroencephalographic-computertomographic comperative study carried out in 430 patients, the concurrence of secondary brain stem damage due to mass displacement and herniation processes and parroxysmal generalised slow activity in the EEG ("intermittant frontal delta rhythms", "projected discharges", "subcortical signs") in intracranial space-occupying processes were studied among others. The occurrence of the EEG pattern was independent of the presence of brain stem displacements in about 20 and 25 per cent, respectively, of the 152 patients with supratentorial space occupations. The absence of the characteristics on 80 per cent of the patients with clear CT criteria for a secondary brain stem impairment shows that it is not suitable as a warning sign of an imminent intracranial decompensation and that in particular from the non-occurrence in the EEG no contribution to the operative risk and to the choice of the time of the operation can be derived. A relation between the occurrence of paroxysmal slow activity and the acuity of the course of the disease or the degree of malignity of cerebral tumours could not be verified. Possible causes of the inconstant occurrence of this EEG pattern in brain stem alterations are discussed.

  15. Research on joint parameter inversion for an integrated underground displacement 3D measuring sensor.

    PubMed

    Shentu, Nanying; Qiu, Guohua; Li, Qing; Tong, Renyuan; Shentu, Nankai; Wang, Yanjie

    2015-04-13

    Underground displacement monitoring is a key means to monitor and evaluate geological disasters and geotechnical projects. There exist few practical instruments able to monitor subsurface horizontal and vertical displacements simultaneously due to monitoring invisibility and complexity. A novel underground displacement 3D measuring sensor had been proposed in our previous studies, and great efforts have been taken in the basic theoretical research of underground displacement sensing and measuring characteristics by virtue of modeling, simulation and experiments. This paper presents an innovative underground displacement joint inversion method by mixing a specific forward modeling approach with an approximate optimization inversion procedure. It can realize a joint inversion of underground horizontal displacement and vertical displacement for the proposed 3D sensor. Comparative studies have been conducted between the measured and inversed parameters of underground horizontal and vertical displacements under a variety of experimental and inverse conditions. The results showed that when experimentally measured horizontal displacements and vertical displacements are both varied within 0~30 mm, horizontal displacement and vertical displacement inversion discrepancies are generally less than 3 mm and 1 mm, respectively, under three kinds of simulated underground displacement monitoring circumstances. This implies that our proposed underground displacement joint inversion method is robust and efficient to predict the measuring values of underground horizontal and vertical displacements for the proposed sensor.

  16. Research on Joint Parameter Inversion for an Integrated Underground Displacement 3D Measuring Sensor

    PubMed Central

    Shentu, Nanying; Qiu, Guohua; Li, Qing; Tong, Renyuan; Shentu, Nankai; Wang, Yanjie

    2015-01-01

    Underground displacement monitoring is a key means to monitor and evaluate geological disasters and geotechnical projects. There exist few practical instruments able to monitor subsurface horizontal and vertical displacements simultaneously due to monitoring invisibility and complexity. A novel underground displacement 3D measuring sensor had been proposed in our previous studies, and great efforts have been taken in the basic theoretical research of underground displacement sensing and measuring characteristics by virtue of modeling, simulation and experiments. This paper presents an innovative underground displacement joint inversion method by mixing a specific forward modeling approach with an approximate optimization inversion procedure. It can realize a joint inversion of underground horizontal displacement and vertical displacement for the proposed 3D sensor. Comparative studies have been conducted between the measured and inversed parameters of underground horizontal and vertical displacements under a variety of experimental and inverse conditions. The results showed that when experimentally measured horizontal displacements and vertical displacements are both varied within 0 ~ 30 mm, horizontal displacement and vertical displacement inversion discrepancies are generally less than 3 mm and 1 mm, respectively, under three kinds of simulated underground displacement monitoring circumstances. This implies that our proposed underground displacement joint inversion method is robust and efficient to predict the measuring values of underground horizontal and vertical displacements for the proposed sensor. PMID:25871714

  17. 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.

  18. Indoor Environmental Quality in Mechanically Ventilated, Energy-Efficient Buildings vs. Conventional Buildings

    PubMed Central

    Wallner, Peter; Munoz, Ute; Tappler, Peter; Wanka, Anna; Kundi, Michael; Shelton, Janie F.; Hutter, Hans-Peter

    2015-01-01

    Energy-efficient buildings need mechanical ventilation. However, there are concerns that inadequate mechanical ventilation may lead to impaired indoor air quality. Using a semi-experimental field study, we investigated if exposure of occupants of two types of buildings (mechanical vs. natural ventilation) differs with regard to indoor air pollutants and climate factors. We investigated living and bedrooms in 123 buildings (62 highly energy-efficient and 61 conventional buildings) built in the years 2010 to 2012 in Austria (mainly Vienna and Lower Austria). Measurements of indoor parameters (climate, chemical pollutants and biological contaminants) were conducted twice. In total, more than 3000 measurements were performed. Almost all indoor air quality and room climate parameters showed significantly better results in mechanically ventilated homes compared to those relying on ventilation from open windows and/or doors. This study does not support the hypothesis that occupants in mechanically ventilated low energy houses are exposed to lower indoor air quality. PMID:26561823

  19. Indoor Environmental Quality in Mechanically Ventilated, Energy-Efficient Buildings vs. Conventional Buildings.

    PubMed

    Wallner, Peter; Munoz, Ute; Tappler, Peter; Wanka, Anna; Kundi, Michael; Shelton, Janie F; Hutter, Hans-Peter

    2015-11-06

    Energy-efficient buildings need mechanical ventilation. However, there are concerns that inadequate mechanical ventilation may lead to impaired indoor air quality. Using a semi-experimental field study, we investigated if exposure of occupants of two types of buildings (mechanical vs. natural ventilation) differs with regard to indoor air pollutants and climate factors. We investigated living and bedrooms in 123 buildings (62 highly energy-efficient and 61 conventional buildings) built in the years 2010 to 2012 in Austria (mainly Vienna and Lower Austria). Measurements of indoor parameters (climate, chemical pollutants and biological contaminants) were conducted twice. In total, more than 3000 measurements were performed. Almost all indoor air quality and room climate parameters showed significantly better results in mechanically ventilated homes compared to those relying on ventilation from open windows and/or doors. This study does not support the hypothesis that occupants in mechanically ventilated low energy houses are exposed to lower indoor air quality.

  20. Ventilator-associated pneumonia--the wrong quality measure for benchmarking.

    PubMed

    Klompas, Michael; Platt, Richard

    2007-12-04

    Legislators, payers, and quality-of-care advocates across the United States are considering requiring hospitals to report ventilator-associated pneumonia rates as a way to benchmark and reward quality of care. Accurate diagnosis of ventilator-associated pneumonia, however, is notoriously difficult because several common complications of critical care can mimic the clinical appearance of ventilator-associated pneumonia. The challenge is compounded by substantial subjectivity inherent in the current surveillance definition. These sources of variability make ventilator-associated pneumonia rates difficult to acquire, interpret, and compare both within and among institutions. Ventilator-associated pneumonia should be excluded from compulsory reporting initiatives until we develop and validate more objective outcome measures that meaningfully reflect quality of care for ventilated patients.

  1. Technology Solutions Case Study: Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    SciTech Connect

    A. Rudd and D. Bergey

    2015-08-01

    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, and 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.

  2. Cost of ventilation and effect of digestive state on the ventilatory response of the tegu lizard.

    PubMed

    Skovgaard, Nini; Wang, Tobias

    2004-07-12

    We performed simultaneous measurements of ventilation, oxygen uptake and carbon dioxide production in the South American lizard, Tupinambis merianae, equipped with a mask and maintained at 25 degrees C. Ventilation of resting animals was stimulated by progressive exposure to hypercapnia (2, 4 and 6%) or hypoxia (15, 10, 8 and 6%) in inspired gas mixture. This was carried out in both fasting and digesting animals. The ventilatory response to hypercapnia and hypoxia were affected by digestive state, with a more vigorous ventilatory response in digesting animals compared to fasting animals. Hypoxia doubled total ventilation while hypercapnia led to a four-fold increase in total ventilation both accomplished through an increase in tidal volume. Oxygen uptake remained constant during all hypercapnic exposures while there was an increase during hypoxia. Cost of ventilation was estimated to be 17% during hypoxia but less than 1% during hypercapnia. Our data indicate that ventilation can be greatly elevated at a small energetic cost.

  3. Propellant Handler's Ensemble (PHE) Aka Self-Contained Atmospheric Protective Ensemble (SCAPE), Ventilator Improvement Study Project

    NASA Technical Reports Server (NTRS)

    Oliva-Buisson, Yvette J. (Compiler)

    2014-01-01

    The overall objective for this project is to evaluate two candidate alternatives for the existing Propellant Handler's Ensemble (PHE) escape ventilator. The new candidate ventilators use newer technology with similar quantities of air at approximately half the weight of the current ventilator. Ventilators are typically used to ingress/egress a hazardous work area when hard line air is provided at the work area but the hose is not long enough to get the operator to and from the staging area to the work area. The intent of this test is to verify that the new ventilators perform as well as or better than the current ventilators in maintaining proper oxygen (O2) and carbon dioxide (CO2) levels in the PHE during a typical use for the rated time period (10 minutes). We will evaluate two new units comparing them to the existing unit. Subjects will wear the Category I version of the Propellant Handler's Ensemble with the rear suit pouch snapped.

  4. Inspiratory work and response times of a modified pediatric volume ventilator during synchronized intermittent mandatory ventilation and pressure support ventilation.

    PubMed

    Martin, L D; Rafferty, J F; Wetzel, R C; Gioia, F R

    1989-12-01

    Volume ventilation by demand flow ventilators significantly increases work of breathing during inspiration. Although various ventilator modifications and different modes of ventilation have been developed, there have been few studies regarding imposed work of breathing in infants and children. This study was designed to evaluate several modifications of a commercially available demand flow ventilator designed to shorten response time (tr) and decrease the imposed work (Wi) involved in opening the demand valve. Minimum withdrawal volume (Vmin), maximum negative pressure (P mneg), and tr were measured. Wi was defined as the product of Vmin and P mneg. Seven Siemens Servo 900C ventilators were tested under 16 different trial conditions with four variables: 1) mode of ventilation (synchronized intermittent mandatory ventilation [SIMV] vs. pressure support ventilation [PSV]); 2) caliber of circuit tubing (adult vs. pediatric); 3) location of airway pressure monitor (distal vs. proximal); and 4) ventilator trigger sensitivity (0 cm H2O--high vs. -2 cm H2O--low). Vmin, Pmneg, and Wi were all decreased (P less than .05) while tr was unaffected by changing ventilator trigger sensitivity from low to high. Wi was decreased by pediatric tubing and proximal airway pressure monitoring only when low trigger sensitivity was used. PSV and proximal airway monitoring shortened tr. The authors conclude that the use of pediatric circuit tubing and proximal airway pressure monitoring with a Siemens Servo 900C ventilator significantly improved ventilator performance.

  5. Rescue high-frequency jet ventilation versus conventional ventilation for severe pulmonary dysfunction in preterm infants.

    PubMed

    Rojas-Reyes, Maria Ximena; Orrego-Rojas, Paola A

    2015-10-16

    Chronic lung disease (CLD) is a major cause of mortality and morbidity in very low birth weight infants despite increased use of antenatal steroids and surfactant therapy. Ventilator injury and oxygen toxicity are thought to be important factors in the pathogenesis of chronic pulmonary disease. Evidence from animal studies and from adult human studies indicates that high-frequency jet ventilation may reduce the severity of lung injury associated with mechanical ventilation. To compare use of high-frequency jet ventilation (HFJV) versus conventional ventilation (CV) in preterm infants with severe pulmonary dysfunction.Subgroup analyses include the following.• Trials with and without surfactant replacement therapy.• Trials with and without strategies to maintain lung volume.• Trials with infants of different gestational ages and birth weights (specific subgroups to include < 28 weeks' gestation and < 1000 grams).• Trials with and without adequate humidification of inspired gases. The original search included MEDLINE (1966 to August 2005), the Cochrane Central Register of Controlled Trials (CENTRAL; 2005, Issue 3) and EMBASE (1988 to August 2005). We also obtained information from experts in the field and checked cross-references. We updated the electronic search in June 2013 and again in June 2015. We included in this systematic review randomised and quasi-randomised controlled trials of rescue high-frequency jet ventilation versus conventional ventilation in preterm infants born at less than 35 weeks' gestation or with birth weight less than 2000 grams in respiratory distress. We used standard methods of the Cochrane Neonatal Review Group, including independent trial assessment and data extraction. We analysed data using risk ratios (RRs) and risk differences (RDs). We included only one trial in the review. Keszler 1991 randomly assigned 166 preterm infants; reported data on 144 infants; and permitted cross-over to the alternate treatment if initial

  6. Residential ventilation standards scoping study

    SciTech Connect

    McKone, Thomas E.; Sherman, Max H.

    2003-10-01

    The goals of this scoping study are to identify research needed to develop improved ventilation standards for California's Title 24 Building Energy Efficiency Standards. The 2008 Title 24 Standards are the primary target for the outcome of this research, but this scoping study is not limited to that timeframe. We prepared this scoping study to provide the California Energy Commission with broad and flexible options for developing a research plan to advance the standards. This document presents the findings of a scoping study commissioned by the Public Interest Energy Research (PIER) program of the California Energy Commission to determine what research is necessary to develop new residential ventilation requirements for California. This study is one of three companion efforts needed to complete the job of determining the ventilation needs of California residences, determining the bases for setting residential ventilation requirements, and determining appropriate ventilation technologies to meet these needs and requirements in an energy efficient manner. Rather than providing research results, this scoping study identifies important research questions along with the level of effort necessary to address these questions and the costs, risks, and benefits of pursuing alternative research questions. In approaching these questions and corresponding levels of effort, feasibility and timing were important considerations. The Commission has specified Summer 2005 as the latest date for completing this research in time to update the 2008 version of California's Energy Code (Title 24).

  7. Effects of energy-efficient ventilation rates on indoor air quality at an Ohio elementary school

    NASA Astrophysics Data System (ADS)

    Berk, J. V.; Young, R.; Hollowell, C. D.; Turiel, I.; Pepper, J.

    1980-04-01

    A mobile laboratory was used to monitor air outdoors and at three indoor sites (two classrooms and a large multipurpose room); tests were made at three different ventilation rates. The parameters measured were outside air flow rates, odor perception, microbial burden, particulate mass, total aldehydes, carbon dioxide, ozone, and nitrogen oxides. The results of these measurements are given and compared with the existing outdoor air quality standards. Carbon dioxide concentrations increased as the ventilation rate decreased, but still did not exceed current standards. Odor perceptibility increased slightly at the lowest ventilation rate. Other pollutants showed very low concentrations, which did not change with reductions in ventilation rate.

  8. Influence of ventilated shrouds on the convective heat transfer to a circular cylinder

    NASA Technical Reports Server (NTRS)

    Daryabeigi, Kamran; Ash, Robert L.; Dillon-Townes, Lawrence A.

    1987-01-01

    Convective heat transfer to shrouded cylinders in transverse flow has been studied over the Reynolds number range 2000-20,000. The influence of shroud ventilation, relative shroud diameters, and orientation of the ventilation holes was studied. In some cases, average inner-cylinder Nusselt numbers were found to exceed the comparable bare-cylinder values by as much as 50 percent. Cylinder heat convection was influenced more by the degree of ventilation and shroud diameter than by hole orientation. An equivalent inner bare cylinder diameter, based on degree of shroud ventilation and shroud diameter, was developed which can be useful in shroud design studies.

  9. Influence of ventilated shrouds on the convective heat transfer to a circular cylinder

    NASA Technical Reports Server (NTRS)

    Daryabeigi, Kamran; Ash, Robert L.; Dillon-Townes, Lawrence A.

    1987-01-01

    Convective heat transfer to shrouded cylinders in transverse flow has been studied over the Reynolds number range 2000-20,000. The influence of shroud ventilation, relative shroud diameters, and orientation of the ventilation holes was studied. In some cases, average inner-cylinder Nusselt numbers were found to exceed the comparable bare-cylinder values by as much as 50 percent. Cylinder heat convection was influenced more by the degree of ventilation and shroud diameter than by hole orientation. An equivalent inner bare cylinder diameter, based on degree of shroud ventilation and shroud diameter, was developed which can be useful in shroud design studies.

  10. Molecular dynamics simulations of threshold displacement energies in Fe

    NASA Astrophysics Data System (ADS)

    Nordlund, K.; Wallenius, J.; Malerba, L.

    2006-05-01

    We compare systematically the threshold displacement energy surface of 11 interatomic potentials in Fe. We discuss in detail different possible definitions of threshold displacement energies, and how they relate to different kinds of experimental threshold displacement energies. We compare the threshold results to experiments, and find that none of the 11 tested potentials agrees fully with experiments. However, all the potentials predict some qualitative features in the same way, most importantly that the threshold energy surface close to the 1 0 0 crystal direction is flat and that the largest threshold energies occur around very roughly the 1 2 3 crystal direction.

  11. Proton displacement damage in light-emitting and laser diodes

    NASA Technical Reports Server (NTRS)

    Johnston, A. H.

    2000-01-01

    The effects of proton displacement damage on light-emitting diodes and laser diodes are discussed, comparing the radiation sensitivity of current technology devices with older devices for which data exists in the literature.

  12. Electron-Induced Displacement Damage Effects in CCDs

    NASA Technical Reports Server (NTRS)

    Becker, Heidi N.; Elliott, Tom; Alexander, James W.

    2006-01-01

    We compare differences in parametric degradation for CCDs irradiated to the same displacement damage dose with 10-MeV and 50-MeV electrons. Charge transfer efficiency degradation was observed to not scale with NIEL for small signals.

  13. Electron-Induced Displacement Damage Effects in CCDs

    NASA Technical Reports Server (NTRS)

    Becker, Heidi N.; Elliott, Tom; Alexander, James W.

    2006-01-01

    We compare differences in parametric degradation for CCDs irradiated to the same displacement damage dose with 10-MeV and 50-MeV electrons. Charge transfer efficiency degradation was observed to not scale with NIEL for small signals.

  14. Effect of Room Ventilation Rates in Rodent Rooms with Direct-Exhaust IVC Systems.

    PubMed

    Geertsema, Roger S; Lindsell, Claire E

    2015-09-01

    When IVC are directly exhausted from a rodent housing room, the air quality of the room can become independent of the intracage air quality and may reduce the need for high room ventilation rates. This study assessed the effect of decreasing the ventilation rate in rodent rooms using direct-exhaust IVC systems. The study was conducted over 16 wk and compared conditions in 8 rodent rooms that had ventilation rates of 5 to 6 air changes per hour (ACH) with those in rooms at 10 to 12 ACH. At the low ventilation rate, rooms had higher CO₂ concentrations, higher dew point temperature, and lower particulate levels and spent a greater percentage of time above the temperature set point than did rooms at the high rate. The levels of allergens and endotoxins in room air were the same regardless of the ventilation rate. Differences seen in parameters within cages at the 2 ventilation rates were operationally irrelevant. We detected no total volatile organic compounds in the room that were attributable to ammonia, regardless of the ventilation rate. Clearing the air of ethanol after a spill took longer at the low compared with high rate. However, ethanol clearance was faster at the low rate when the demand-control system was activated than at the high ventilation rate alone. Air quality in the room and in the cages were acceptable with room ventilation rates of 5 to 6 ACH in rodent rooms that use direct-exhaust IVC systems.

  15. Effect of Room Ventilation Rates in Rodent Rooms with Direct-Exhaust IVC Systems

    PubMed Central

    Geertsema, Roger S; Lindsell, Claire E

    2015-01-01

    When IVC are directly exhausted from a rodent housing room, the air quality of the room can become independent of the intracage air quality and may reduce the need for high room ventilation rates. This study assessed the effect of decreasing the ventilation rate in rodent rooms using direct-exhaust IVC systems. The study was conducted over 16 wk and compared conditions in 8 rodent rooms that had ventilation rates of 5 to 6 air changes per hour (ACH) with those in rooms at 10 to 12 ACH. At the low ventilation rate, rooms had higher CO2 concentrations, higher dew point temperature, and lower particulate levels and spent a greater percentage of time above the temperature set point than did rooms at the high rate. The levels of allergens and endotoxins in room air were the same regardless of the ventilation rate. Differences seen in parameters within cages at the 2 ventilation rates were operationally irrelevant. We detected no total volatile organic compounds in the room that were attributable to ammonia, regardless of the ventilation rate. Clearing the air of ethanol after a spill took longer at the low compared with high rate. However, ethanol clearance was faster at the low rate when the demand-control system was activated than at the high ventilation rate alone. Air quality in the room and in the cages were acceptable with room ventilation rates of 5 to 6 ACH in rodent rooms that use direct-exhaust IVC systems. PMID:26424250

  16. Glacial Ventilation of the North Pacific

    NASA Astrophysics Data System (ADS)

    Keigwin, L. D.; Marchal, O.

    2004-12-01

    Previous work on sediment cores from the North Pacific showed that above ~2 km d13C on the benthic foram Cibicidoides was higher during glacial time than it is today, after correcting for secular change of ~0.3 permil. This led to the suggestion that the ocean was better ventilated either through greater transport of a paleo North Pacific Intermediate Water, or transport was the same as today and preformed d13C was higher ([O2] was higher). Below ~2km, d13C was about the same as today, after correction. A new synthesis of apparent ventilation ages based on the paired benthic (BF) and planktonic foram (PF) 14C method provides general support for the scenario based on d13C. Although many 14C data are available for this synthesis, we exercised some reasonable quality control by selecting data that met the following criteria: (1) analyses based on high deposition rate cores, or laminated intervals of cores, (2) analyses conducted at peaks in BF abundance, and (3) analyses from a narrow window of glacial maximum time (~18-20 ka). The result shows that above ~2.5 km apparent ventilation ages are less than today (better ventilation), and the one sample from >3km is the same as today (~1700 yrs). When d13C and BF-PF 14C data are compared between the North Atlantic and North Pacific Oceans, it seems likely the same water filled these basins deeper than ~3.5 km. d13C of each basin was about 0 permil, and although the average apparent ventilation age was ~1200 yrs for the North Atlantic during the LGM, the two oldest determinations are 1550 and 1450 yrs. The fly in the ointment is still the very low d13C observed in the South Atlantic sector of the Southern Ocean. Although the available data are reproducible and may not reflect low d13C in the fluff layer at the seafloor, results from a zonally averaged circulation-biogeochemistry model showed that d13C may become unlinked from nutrient content during a change of the ocean general circulation.

  17. Apes Communicate about Absent and Displaced Objects: Methodology Matters

    PubMed Central

    Lyn, Heidi; Russell, Jamie L.; Leavens, David A.; Bard, Kim A.; Boysen, Sarah T.; Schaeffer, Jennifer A.; Hopkins, William D.

    2013-01-01

    Displaced reference is the ability to refer to an item that has been moved (displaced) in space and/or time, and has been called one of the true hallmarks of referential communication. Several studies suggest that nonhuman primates have this capability, but a recent experiment concluded that in a specific situation (absent entities) human infants display displaced reference but chimpanzees do not. Here we show that chimpanzees and bonobos of diverse rearing histories are capable of displaced reference to absent and displaced objects. It is likely that some of the conflicting findings from animal cognition studies are due to relatively minor methodological differences, but are compounded by interpretation errors. Comparative studies are of great importance in elucidating the evolution of human cognition, however, greater care must be taken with methodology and interpretation for these studies to accurately reflect species differences. PMID:23681052

  18. Impact of ventilator adjustment and sedation-analgesia practices on severe asynchrony in patients ventilated in assist-control mode.

    PubMed

    Chanques, Gerald; Kress, John P; Pohlman, Anne; Patel, Shruti; Poston, Jason; Jaber, Samir; Hall, Jesse B

    2013-09-01

    Breath-stacking asynchrony during assist-control-mode ventilation may be associated with increased tidal volume and alveolar pressure that could contribute to ventilator-induced lung injury. Methods to reduce breath stacking have not been well studied. The objective of this investigation was to evaluate 1) which interventions were used by managing clinicians to address severe breath stacking; and 2) how effective these measures were. Sixteen-bed medical ICU. Physiological study in consecutively admitted patients without severe brain injury, who had severe breath stacking defined as an asynchrony index greater than or equal to 10% of total breaths. During 30 minutes before (baseline) and after any intervention employed by the managing clinician, the ventilator flow, airway pressure, and volume/time waveforms were continuously recorded and analyzed to detect normal and stacked breaths. The initial approach taken was assigned to one of three categories: no intervention, increase of sedation-analgesia, or change of ventilator setting. Nonparametric Wilcoxon-Mann-Whitney tests and multiple regression were used for statistical analysis. Quantitative data are presented as median [25-75]. Sixty-six of 254 (26%) mechanically ventilated patients exhibited severe breath-stacking asynchrony. A total of 100 30-minute sequences were recorded and analyzed in 30 patients before and after 50 clinical decisions for ongoing management (no intervention, n=8; increasing sedation/analgesia, n=16; ventilator adjustment, n=26). Breath-stacking asynchrony index was 44 [27-87]% at baseline. Compared with baseline, the decrease of asynchrony index was greater after changing the ventilator setting (-99 [-92, -100]%) than after increasing the sedation-analgesia (-41 [-66, 7]%, p<0.001) or deciding to tolerate the asynchrony (4 [-4, 12]%, p<0.001). Pressure-support ventilation and increased inspiratory time were independently associated with the reduction of asynchrony index. Compared with

  19. [Nasopharyngeal myiasis during mechanical ventilation].

    PubMed

    Yoshitomi, A; Sato, A; Suda, T; Chida, K

    1997-12-01

    We report a case of myiasis caused by Phaenicia sericata during mechanical ventilation. An 86-year-old woman with bronchiectasis was admitted to our hospital with severe respiratory failure. Treatment with mechanical ventilation and sedatives was initiated. On the 10th day of hospitalization, about 20 white larvae were found in the patient's oral or nasal cavities. The larvae were removed and identified as Phaenicia sericata. No mucosal injury was found in the patient's oral or nasal cavity by endoscopic examination. The patient died of multiple organ failure caused by sepsis that had no association with myiasis. From the clinical course and the fly's life cycle, it is considered that the fly laid eggs in the patient's oral or nasal cavity while she was sedated during mechanical ventilation. Myiasis can occur even in a hospital.

  20. Ventilation imaging of the lung: comparison of hyperpolarized helium-3 MR imaging with Xe-133 scintigraphy.

    PubMed

    Altes, Talissa A; Rehm, Patrice K; Harrell, Frank; Salerno, Michael; Daniel, Thomas M; De Lange, Eduard E

    2004-07-01

    To compare hyperpolarized helium-3 (HHe) magnetic resonance imaging (MRI) of the lung with standard Xe-133 lung ventilation scintigraphy. We performed a retrospective review of 15 subjects who underwent HHe MRI and Xe-133 lung ventilation imaging. Coronal MRI sections were acquired after a single inhalation of HHe gas, and standard posterior planar lung ventilation scintigraphy was performed during continuous breathing of Xe-133 gas. The first breath scintigram of each patient was compared with a composite MR image composed of the sum of the individual MR images and with the individual helium-3 MR images. Ventilation defects on the two imaging modalities were compared for size, conspicuity, and concordance in presence and location. Assessment was done separately for each of four lung quadrants. Comparing the composite HHe MR images with Xe-133 scintigraphy, ventilation defect size, conspicuity and concordance were the same in 67% (40/60), 63% (38/60), and 62% (37/60) quadrants, respectively. Comparing the individual HHe MR image sections with the Xe-133 ventilation scan, there was concordance between the ventilation defects in 27% (16/60) of quadrants. More defects were identified on the individual HHe MR images in 62% (37/60) of quadrants. There was good agreement between composite HHe MR image and first breath Xe-133 scintigraphic images, supporting the widely held assumption that HHe MRI likely depicts first breath lung ventilation.

  1. Analysis of atelectasis, ventilated, and hyperinflated lung during mechanical ventilation by dynamic CT.

    PubMed

    David, Matthias; Karmrodt, Jens; Bletz, Carsten; David, Sybil; Herweling, Annette; Kauczor, Hans-Ulrich; Markstaller, Klaus

    2005-11-01

    To study the dynamics of lung compartments by dynamic CT (dCT) imaging during uninterrupted pressure-controlled ventilation (PCV) and different positive end-expiratory pressure (PEEP) settings in healthy and damaged lungs. Experimental animal investigation. Experimental animal facility of a university department. In seven anesthetized pigs, static inspiratory pressure volume curves were obtained to identify the individual lower inflection point (LIP) before and after saline solution lung lavage. During PCV, PEEP was adjusted 5 millibars (mbar) below the individually determined LIP (LIP - 5), at the LIP, and 5 mbar above the LIP (LIP + 5). Measurements were repeated before and after induction of lung damage. Hemodynamics, arterial and mixed venous blood gases, and dCT imaging in one juxtadiaphragmatic slice (effective temporal resolution of 100 ms) were assessed during uninterrupted PCV in series of three successive respiratory cycles. The mean fractional area (FA) of the hyperinflated lung (FA-H), mean FA of ventilated lung, mean FA of poorly ventilated lung, and mean FA of nonventilated lung (FA-NV), and the change in FA of the whole lung area (DeltaFA) were compared at different PEEP settings. Calculated pulmonary shunt (Qs/Qt) was compared to FA-NV. LIP + 5 decreased the amount of atelectasis (FA-NV) and increased hyperinflation (FA-H) in healthy and injured lungs. Cyclic changes of atelectasis (DeltaFA-NV) and hyperinflation (DeltaFA-H) were observed in both healthy and injured lungs. In the injured but not in the healthy lungs, the amount of cyclic changes of atelectasis and hyperinflation were independent from the adjusted PEEP level. FA-NV correlated with the calculated Qs/Qt, with a slight overestimation (mean +/- SEM, 2.1 +/- 4.1%). dCT imaging allows the following: (1) the quantification of the extent of atelectasis, ventilated, poorly ventilated, and hyperinflated lung parenchyma during ongoing mechanical ventilation; (2) the detection and quantification

  2. Comparative analysis of neonicotinoid binding to insect membranes: I. A structure-activity study of the mode of [3H]imidacloprid displacement in Myzus persicae and Aphis craccivora.

    PubMed

    Kayser, Hartmut; Lee, Connie; Decock, Arnaud; Baur, Markus; Haettenschwiler, Joerg; Maienfisch, Peter

    2004-10-01

    Neonicotinoids bind selectively to insect nicotinic acetylcholine receptors with nanomolar affinity to act as potent insecticides. While the members of the neonicotinoid class have many structural features in common, it is not known whether they also share the same mode of binding to the target receptor. Previous competition studies with [3H]imidacloprid, the first commercialised neonicotinoid, indicated that thiamethoxam, representing a novel structural sub-class, may bind in a different way from that of other neonicotinoids. In the present work we analysed the mode of [3H]imidacloprid displacement by established neonicotinoids and newly synthesized analogues in the aphids Myzus persicae Sulzer and Aphis craccivora Koch. We found two classes of neonicotinoids with distinct modes of interference with [3H]imidacloprid, described as direct competitive inhibition and non-competitive inhibition, respectively. Competitive neonicotinoids were acetamiprid, nitenpyram, thiacloprid, clothianidin and nithiazine, whereas thiamethoxam and the N-methyl analogues of imidacloprid and clothianidin showed non-competitive inhibition. The chloropyridine or chlorothiazole heterocycles, the polar pharmacophore parts, such as nitroimino, cyanoimino and nitromethylene, and the cyclic or acyclic structure of the pharmacophore were not relevant for the mode of inhibition. Consensus structural features of the neonicotinoids were defined for the two mechanisms of interaction with [3H]imidacloprid binding. Furthermore, two sub-classes of non-competitive inhibitors can be discriminated on the basis of their Hill coefficients for imidacloprid displacement. We conclude from the present data that the direct competitors share the binding site with imidacloprid, whereas non-competitive compounds, like thiamethoxam, bind to a different site or in a different mode.

  3. Job Displacement Among Single Mothers:

    PubMed Central

    Brand, Jennie E.; Thomas, Juli Simon

    2015-01-01

    Given the recent era of economic upheaval, studying the effects of job displacement has seldom been so timely and consequential. Despite a large literature associating displacement with worker well-being, relatively few studies focus on the effects of parental displacement on child well-being, and fewer still focus on implications for children of single parent households. Moreover, notwithstanding a large literature on the relationship between single motherhood and children’s outcomes, research on intergenerational effects of involuntary employment separations among single mothers is limited. Using 30 years of nationally representative panel data and propensity score matching methods, we find significant negative effects of job displacement among single mothers on children’s educational attainment and social-psychological well-being in young adulthood. Effects are concentrated among older children and children whose mothers had a low likelihood of displacement, suggesting an important role for social stigma and relative deprivation in the effects of socioeconomic shocks on child well-being. PMID:25032267

  4. Human versus Computer Controlled Selection of Ventilator Settings: An Evaluation of Adaptive Support Ventilation and Mid-Frequency Ventilation.

    PubMed

    Mireles-Cabodevila, Eduardo; Diaz-Guzman, Enrique; Arroliga, Alejandro C; Chatburn, Robert L

    2012-01-01

    Background. There are modes of mechanical ventilation that can select ventilator settings with computer controlled algorithms (targeting schemes). Two examples are adaptive support ventilation (ASV) and mid-frequency ventilation (MFV). We studied how different clinician-chosen ventilator settings are from these computer algorithms under different scenarios. Methods. A survey of critical care clinicians provided reference ventilator settings for a 70 kg paralyzed patient in five clinical/physiological scenarios. The survey-derived values for minute ventilation and minute alveolar ventilation were used as goals for ASV and MFV, respectively. A lung simulator programmed with each scenario's respiratory system characteristics was ventilated using the clinician, ASV, and MFV settings. Results. Tidal volumes ranged from 6.1 to 8.3 mL/kg for the clinician, 6.7 to 11.9 mL/kg for ASV, and 3.5 to 9.9 mL/kg for MFV. Inspiratory pressures were lower for ASV and MFV. Clinician-selected tidal volumes were similar to the ASV settings for all scenarios except for asthma, in which the tidal volumes were larger for ASV and MFV. MFV delivered the same alveolar minute ventilation with higher end expiratory and lower end inspiratory volumes. Conclusions. There are differences and similarities among initial ventilator settings selected by humans and computers for various clinical scenarios. The ventilation outcomes are the result of the lung physiological characteristics and their interaction with the targeting scheme.

  5. 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.

  6. The School Advanced Ventilation Engineering Software (SAVES)

    EPA Pesticide Factsheets

    The School Advanced Ventilation Engineering Software (SAVES) package is a tool to help school designers assess the potential financial payback and indoor humidity control benefits of Energy Recovery Ventilation (ERV) systems for school applications.

  7. A Pediatric Approach to Ventilator-Associated Events Surveillance.

    PubMed

    Cocoros, Noelle M; Priebe, Gregory P; Logan, Latania K; Coffin, Susan; Larsen, Gitte; Toltzis, Philip; Sandora, Thomas J; Harper, Marvin; Sammons, Julia S; Gray, James E; Goldmann, Donald; Horan, Kelly; Burton, Michael; Checchia, Paul A; Lakoma, Matthew; Sims, Shannon; Klompas, Michael; Lee, Grace M

    2017-03-01

    OBJECTIVE Adult ventilator-associated event (VAE) definitions include ventilator-associated conditions (VAC) and subcategories for infection-related ventilator-associated complications (IVAC) and possible ventilator-associated pneumonia (PVAP). We explored these definitions for children. DESIGN Retrospective cohort SETTING Pediatric, cardiac, or neonatal intensive care units (ICUs) in 6 US hospitals PATIENTS Patients ≤18 years old ventilated for ≥1 day METHODS We identified patients with pediatric VAC based on previously proposed criteria. We applied adult temperature, white blood cell count, antibiotic, and culture criteria for IVAC and PVAP to these patients. We matched pediatric VAC patients with controls and evaluated associations with adverse outcomes using Cox proportional hazards models. RESULTS In total, 233 pediatric VACs (12,167 ventilation episodes) were identified. In the cardiac ICU (CICU), 62.5% of VACs met adult IVAC criteria; in the pediatric ICU (PICU), 54.2% of VACs met adult IVAC criteria; and in the neonatal ICU (NICU), 20.2% of VACs met adult IVAC criteria. Most patients had abnormal white blood cell counts and temperatures; we therefore recommend simplifying surveillance by focusing on "pediatric VAC with antimicrobial use" (pediatric AVAC). Pediatric AVAC with a positive respiratory diagnostic test ("pediatric PVAP") occurred in 8.9% of VACs in the CICU, 13.3% of VACs in the PICU, and 4.3% of VACs in the NICU. Hospital mortality was increased, and hospital and ICU length of stay and duration of ventilation were prolonged among all pediatric VAE subsets compared with controls. CONCLUSIONS We propose pediatric AVAC for surveillance related to antimicrobial use, with pediatric PVAP as a subset of AVAC. Studies on generalizability and responsiveness of these metrics to quality improvement initiatives are needed, as are studies to determine whether lower pediatric VAE rates are associated with improvements in other outcomes. Infect Control

  8. Relationship of potassium ions and blood lactate to ventilation during exercise.

    PubMed

    McMurray, Robert G; Tenan, Matthew S

    2010-10-01

    Ventilatory control during exercise is a complex network of neural and humoral signals. One humoral input that has received little recent attention in the exercise literature is potassium ions [K(+)]. The purpose of this study was to examine the relationship between [K(+)] and ventilation during an incremental cycle test and to determine if the relationship between [K(+)] and ventilation differs when blood lactate [lac-] is manipulated. Eight experienced triathletes (4 of each sex) completed 2 incremental, progressive (5-min stages) cycle tests to volitional fatigue: 1 with normal glycogen stores and 1 with reduced glycogen. Minute ventilation was measured during the final minute of each stage, and blood [lac(-)] and [K+] were measured at the end of each exercise stage. Minute ventilation and [K(+)] increased with exercise intensity and were similar between trials (p > 0.5), despite lower [lac-] during the reduced-glycogen trial. The concordance correlations (R(c)) between [lac(-)] and minute ventilation were stronger for both trials (R(c) = approximately 0.88-0.96), but the slopes of the relationships were different than the relationships between [K(+)] and minute ventilation (R(c) = approximately 0.76-0.89). The slope of the relationship between [lac-] and minute ventilation was not as steep during the reduced-glycogen trial, compared with the normal trial (p = 0.002). Conversely, the slope of the relationships between [K(+)] and minute ventilation did not change between trials (p = 0.454). The consistent relationship of minute ventilation and blood [K(+)] during exercise suggests a role for this ion in the control of ventilation during exercise. Conversely, the inconsistent relationship between blood lactate and ventilation brings into question the importance of the relationship between lactate and ventilation during exercise.

  9. 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).

  10. Mechanical ventilation reduces rat diaphragm blood flow and impairs oxygen delivery and uptake.

    PubMed

    Davis, Robert T; Bruells, Christian S; Stabley, John N; McCullough, Danielle J; Powers, Scott K; Behnke, Bradley J

    2012-10-01

    Although mechanical ventilation is a life-saving intervention in patients suffering from respiratory failure, prolonged mechanical ventilation is often associated with numerous complications including problematic weaning. In contracting skeletal muscle, inadequate oxygen supply can limit oxidative phosphorylation resulting in muscular fatigue. However, whether prolonged mechanical ventilation results in decreased diaphragmatic blood flow and induces an oxygen supply-demand imbalance in the diaphragm remains unknown. We tested the hypothesis that prolonged controlled mechanical ventilation results in a time-dependent reduction in rat diaphragmatic blood flow and microvascular PO2 and that prolonged mechanical ventilation would diminish the diaphragm's ability to increase blood flow in response to muscular contractions. Compared to 30 mins of mechanical ventilation, 6 hrs of mechanical ventilation resulted in a 75% reduction in diaphragm blood flow (via radiolabeled microspheres), which did not occur in the intercostal muscle or high-oxidative hindlimb muscle (e.g., soleus). There was also a time-dependent decline in diaphragm microvascular PO2 (via phosphorescence quenching). Further, contrary to 30 mins of mechanical ventilation, 6 hrs of mechanical ventilation significantly compromised the diaphragm's ability to increase blood flow during electrically-induced contractions, which resulted in a ~80% reduction in diaphragm oxygen uptake. In contrast, 6 hrs of spontaneous breathing in anesthetized animals did not alter diaphragm blood flow or the ability to augment flow during electrically-induced contractions. These new and important findings reveal that prolonged mechanical ventilation results in a time-dependent decrease in the ability of the diaphragm to augment blood flow to match oxygen demand in response to contractile activity and could be a key contributing factor to difficult weaning. Although additional experiments are required to confirm, it is tempting to

  11. Perceived displacement explains wolfpack effect

    PubMed Central

    Šimkovic, Matúš; Träuble, Birgit

    2014-01-01

    We investigate the influence of perceived displacement of moving agent-like stimuli on the performance in dynamic interactive tasks. In order to reliably measure perceived displacement we utilize multiple tasks with different task demands. The perceived center of an agent's body is displaced in the direction in which the agent is facing and this perceived displacement is larger than the theoretical position of the center of mass would predict. Furthermore, the displacement in the explicit judgment is dissociated from the displacement obtained by the implicit measures. By manipulating the location of the pivot point, we show that it is not necessary to postulate orientation as an additional cue utilized by perception, as has been suggested by earlier studies. These studies showed that the agent's orientation influences the detection of chasing motion and the detection-related performance in interactive tasks. This influence has been labeled wolfpack effect. In one of the demonstrations of the wolfpack effect participants control a green circle on a display with a computer mouse. It has been shown that participants avoid display areas with agents pointing toward the green circle. Participants do so in favor of areas where the agents point in the direction perpendicular to the circle. We show that this avoidance behavior arises because the agent's pivot point selected by the earlier studies is different from where people locate the center of agent's body. As a consequence, the nominal rotation confounds rotation and translation. We show that the avoidance behavior disappears once the pivot point is set to the center of agent's body. PMID:25566114

  12. 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.

  13. Bench testing of a new hyperbaric chamber ventilator at different atmospheric pressures.

    PubMed

    Lefebvre, Jean-Claude; Lyazidi, Aissam; Parceiro, Miguel; Sferrazza Papa, Giuseppe F; Akoumianaki, Evangelia; Pugin, Deborah; Tassaux, Didier; Brochard, Laurent; Richard, Jean-Christophe M

    2012-08-01

    Providing mechanical ventilation is challenging at supra-atmospheric pressure. The higher gas density increases resistance, reducing the flow delivered by the ventilator. A new hyperbaric ventilator (Siaretron IPER 1000) is said to compensate for these effects automatically. The aim of this bench test study was to validate the compensation, define its limits and provide details on the ventilator's output at varied atmospheric pressures. Experiments were conducted inside a multiplace hyperbaric chamber at 1, 2.2, 2.8 and 4 atmospheres absolute (ATA), with the ventilator connected to a test lung. Transducers were recalibrated at each ATA level. Various ventilator settings were tested in volume and pressure control modes. Measured tidal volumes were compared with theoretical predictions based on gas laws. Results confirmed the ventilator's ability to provide compensation, but also identified its limits. The compensation range could be predicted and depended on the maximal flow attainable, decreasing linearly with increasing atmospheric pressure. With settings inside the range, tidal volumes approximated set values (mean error 10 ± 5 %). With settings outside the range, the volume was limited to the predicted maximal value calculated from maximal flow. A practical guide for clinicians is provided. The IPER 1000 ventilator attempted to deliver stable tidal volume by adjusting the opening of the inspiratory valve in proportion to atmospheric pressure. Adequate compensation was observed, albeit only within a predictable range, which can be reliably predicted for each setting and ATA level combination. Setting a tidal volume outside this range can result in an unwanted decrease in minute ventilation.

  14. Controlled ventilation or spontaneous respiration in anesthesia for tracheobronchial foreign body removal: a meta-analysis.

    PubMed

    Liu, Yuqi; Chen, Lianhua; Li, Shitong

    2014-10-01

    Either controlled ventilation or spontaneous respiration is commonly used in general anesthesia for inhaled foreign body removal via rigid bronchoscopy. Controversy in the literature exists concerning which form of ventilation is optimally suited for bronchoscopy. We performed a meta-analysis to compare controlled ventilation and spontaneous respiration with respect to complications, operation time, and anesthesia recovery time. We searched MEDLINE (1946-2013) and the Cochrane Central Register of Controlled Trials, EMBASE. The articles were evaluated for validity, and the data on complications, including desaturation, laryngospasm, laryngeal edema, bucking and coughing, body movement, breath holding, operation time, and anesthesia recovery time, were extracted by the authors and summarized using odds ratios, mean differences, and 95% confidence intervals (CIs). From the included studies, 423 subjects received controlled ventilation, whereas 441 subjects received spontaneous respiration. There was no significant difference in the incidence of desaturation between controlled ventilation and spontaneous respiration (odds ratio, 0.70; 95% CI, 0.30-1.63). However, the incidence of laryngospasm was lower when controlled ventilation was performed (OR, 0.27; 95% CI, 0.10-0.76). The operation time (mean difference, -9.07 min; 95% CI, -14.03 to -4.12) was shorter in the controlled ventilation group. Current evidence does not show a preference for either controlled ventilation or spontaneous respiration, although laryngospasm has a lower incidence when controlled ventilation is performed. Additional clinical studies are required to substantiate this issue. © 2014 John Wiley & Sons Ltd.

  15. Building America Case Study: Ventilation System Effectiveness and Tested Indoor Air Quality Impacts, Tyler, Texas

    SciTech Connect

    2015-08-01

    ?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, and 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.

  16. 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.

  17. Reproducibility of intensity-based estimates of lung ventilation

    PubMed Central

    Du, Kaifang; Bayouth, John E.; Ding, Kai; Christensen, Gary E.; Cao, Kunlin; Reinhardt, Joseph M.

    2013-01-01

    Purpose: Lung function depends on lung expansion and contraction during the respiratory cycle. Respiratory-gated CT imaging and image registration can be used to estimate the regional lung volume change by observing CT voxel density changes during inspiration or expiration. In this study, the authors examine the reproducibility of intensity-based estimates of lung tissue expansion and contraction in three mechanically ventilated sheep and ten spontaneously breathing humans. The intensity-based estimates are compared to the estimates of lung function derived from image registration deformation field. Methods: 4DCT data set was acquired for a cohort of spontaneously breathing humans and anesthetized and mechanically ventilated sheep. For each subject, two 4DCT scans were performed with a short time interval between acquisitions. From each 4DCT data set, an image pair consisting of a volume reconstructed near end inspiration and a volume reconstructed near end exhalation was selected. The end inspiration and end exhalation images were registered using a tissue volume preserving deformable registration algorithm. The CT density change in the registered image pair was used to compute intensity-based specific air volume change (SAC) and the intensity-based Jacobian (IJAC), while the transformation-based Jacobian (TJAC) was computed directly from the image registration deformation field. IJAC is introduced to make the intensity-based and transformation-based methods comparable since SAC and Jacobian may not be associated with the same physiological phenomenon and have different units. Scan-to-scan variations in respiratory effort were corrected using a global scaling factor for normalization. A gamma index metric was introduced to quantify voxel-by-voxel reproducibility considering both differences in ventilation and distance between matching voxels. The authors also tested how different CT prefiltering levels affected intensity-based ventilation reproducibility. Results

  18. Particle displacement tracking for PIV

    NASA Technical Reports Server (NTRS)

    Wernet, Mark P.

    1990-01-01

    A new Particle Imaging Velocimetry (PIV) data acquisition and analysis system, which is an order of magnitude faster than any previously proposed system has been constructed and tested. The new Particle Displacement Tracing (PDT) system is an all electronic technique employing a video camera and a large memory buffer frame-grabber board. Using a simple encoding scheme, a time sequence of single exposure images are time coded into a single image and then processed to track particle displacements and determine velocity vectors. Application of the PDT technique to a counter-rotating vortex flow produced over 1100 velocity vectors in 110 seconds when processed on an 80386 PC.

  19. Rotor component displacement measurement system

    DOEpatents

    Mercer, Gary D.; Li, Ming C.; Baum, Charles R.

    2003-05-27

    A measuring system for measuring axial displacement of a tube relative to an axially stationary component in a rotating rotor assembly includes at least one displacement sensor adapted to be located normal to a longitudinal axis of the tube; an insulated cable system adapted for passage through the rotor assembly; a rotatable proximitor module located axially beyond the rotor assembly to which the cables are connected; and a telemetry system operatively connected to the proximitor module for sampling signals from the proximitor module and forwarding data to a ground station.

  20. Displaced plaque in retroperitoneal adenopathy.

    PubMed

    Al-Okaili, Riyadh N; Schable, Stephen I; Marlow, Troy J

    2002-08-01

    This study was designed to determine when to consider incidental retroperitoneal masses on the basis of a displaced calcified atheromatous abdominal aorta on lateral radiographs. We did a retrospective review of 143 normal abdominal helical computed tomography scans of individuals aged 50 years and older to measure the distance between the posterior aortic wall and anterior cortex of vertebral bodies from T12 through L3. The normal abdominal aorta maintains a close relationship to the vertebral column. The distance should not be more than 10 mm in men and 7.3 mm in women. Displacement of aortic calcified atheroma greater than these distances should prompt a search for a retroperitoneal mass.

  1. Inadequate face mask ventilation--clinical applications.

    PubMed

    Goranović, Tatjana; Milić, Morena; Holjevac, Jadranka Katancić; Maldini, Branka; Sakić, Katarina

    2010-09-01

    Face mask ventilation is a life saving technique. This article will review aetiology and patophysiological consequences of inadequate mask ventilation. The main focus will be on circulatory changes during induction of anesthesia, before and in a short period after intubation that could be attributed to inadequate mask ventilation in humans.

  2. 30 CFR 57.8520 - Ventilation plan.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... system; (4) Locations of all main, booster and auxiliary fans not shown in paragraph (d) of this standard...) Significant changes in the ventilation system projected for one year. (c) Mine fan data for all active main... Underground Only § 57.8520 Ventilation plan. A plan of the mine ventilation system shall be set out by the...

  3. 14 CFR 27.831 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Personnel and Cargo Accommodations § 27.831 Ventilation. (a) The ventilating system for the pilot and passenger compartments must be designed to prevent... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Ventilation. 27.831 Section...

  4. 14 CFR 27.831 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Personnel and Cargo Accommodations § 27.831 Ventilation. (a) The ventilating system for the pilot and passenger compartments must be designed to prevent... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ventilation. 27.831 Section...

  5. 14 CFR 27.831 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Personnel and Cargo Accommodations § 27.831 Ventilation. (a) The ventilating system for the pilot and passenger compartments must be designed to prevent... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Ventilation. 27.831 Section...

  6. 14 CFR 27.831 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Personnel and Cargo Accommodations § 27.831 Ventilation. (a) The ventilating system for the pilot and passenger compartments must be designed to prevent... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Ventilation. 27.831 Section...

  7. 46 CFR 194.15-5 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) Ventilation of air conditioning systems serving the chemical laboratory shall be designed so that air cannot... 46 Shipping 7 2012-10-01 2012-10-01 false Ventilation. 194.15-5 Section 194.15-5 Shipping COAST....15-5 Ventilation. (a) Operations, reactions or experiments which produce toxic, noxious or...

  8. 14 CFR 27.831 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Personnel and Cargo Accommodations § 27.831 Ventilation. (a) The ventilating system for the pilot and passenger compartments must be designed to prevent... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Ventilation. 27.831 Section...

  9. 46 CFR 194.15-5 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...) Ventilation of air conditioning systems serving the chemical laboratory shall be designed so that air cannot... 46 Shipping 7 2011-10-01 2011-10-01 false Ventilation. 194.15-5 Section 194.15-5 Shipping COAST....15-5 Ventilation. (a) Operations, reactions or experiments which produce toxic, noxious or...

  10. 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...

  11. 46 CFR 116.610 - Ventilation ducts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... type of piping, chamber, or conduit used for ventilation. (b) A ventilation duct, and materials incidental to its installation, must be made of noncombustible material. (c) Combustibles and other foreign materials are not allowed within ventilation ducts. However, metal piping and electrical wiring installed in...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 14 CFR 125.117 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 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...

  17. 14 CFR 125.117 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 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...

  18. 9 CFR 91.21 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Ventilation. 91.21 Section 91.21... LIVESTOCK FOR EXPORTATION Inspection of Vessels and Accommodations § 91.21 Ventilation. Each underdeck... mechanical ventilation that will furnish a complete change of air in each compartment every 2 minutes...

  19. 14 CFR 125.117 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 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...

  20. 14 CFR 125.117 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 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...

  1. 33 CFR 175.201 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Ventilation. 175.201 Section 175.201 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY EQUIPMENT REQUIREMENTS Ventilation § 175.201 Ventilation. No person may operate a boat built...

  2. 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...

  3. 33 CFR 175.201 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Ventilation. 175.201 Section 175... SAFETY EQUIPMENT REQUIREMENTS Ventilation § 175.201 Ventilation. No person may operate a boat built after July 31, 1980, that has a gasoline engine for electrical generation, mechanical power, or...

  4. Impact of Four-Dimensional Computed Tomography Pulmonary Ventilation Imaging-Based Functional Avoidance for Lung Cancer Radiotherapy

    SciTech Connect

    Yamamoto, Tokihiro; Kabus, Sven; Berg, Jens von; Lorenz, Cristian; Keall, Paul J.

    2011-01-01

    Purpose: To quantify the dosimetric impact of four-dimensional computed tomography (4D-CT) pulmonary ventilation imaging-based functional treatment planning that avoids high-functional lung regions. Methods and Materials: 4D-CT ventilation images were created from 15 non-small-cell lung cancer patients using deformable image registration and quantitative analysis of the resultant displacement vector field. For each patient, anatomic and functional plans were created for intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT). Consistent beam angles and dose-volume constraints were used for all cases. The plans with Radiation Therapy Oncology Group (RTOG) 0617-defined major deviations were modified until clinically acceptable. Functional planning spared the high-functional lung, and anatomic planning treated the lungs as uniformly functional. We quantified the impact of functional planning compared with anatomic planning using the two- or one-tailed t test. Results: Functional planning led to significant reductions in the high-functional lung dose, without significantly increasing other critical organ doses, but at the expense of significantly degraded the planning target volume (PTV) conformity and homogeneity. The average reduction in the high-functional lung mean dose was 1.8 Gy for IMRT (p < .001) and 2.0 Gy for VMAT (p < .001). Significantly larger changes occurred in the metrics for patients with a larger amount of high-functional lung adjacent to the PTV. Conclusion: The results of the present study have demonstrated the impact of 4D-CT ventilation imaging-based functional planning for IMRT and VMAT for the first time. Our findings indicate the potential of functional planning in lung functional avoidance for both IMRT and VMAT, particularly for patients who have high-functional lung adjacent to the PTV.

  5. How minimum detectable displacement in a GNSS Monitoring Network change?

    NASA Astrophysics Data System (ADS)

    Hilmi Erkoç, Muharrem; Doǧan, Uǧur; Aydın, Cüneyt

    2016-04-01

    The minimum detectable displacement in a geodetic monitoring network shows the displacement magnitude which may be just discriminated with known error probabilities. This displacement, which is originally deduced from sensitivity analysis, depends on network design, observation accuracy, datum of the network, direction of the displacement and power of the statistical test used for detecting the displacements. One may investigate how different scenarios on network design and observation accuracies influence the minimum detectable displacements for the specified datum, a-priorly forecasted directions and assumed power of the test and decide which scenario is the best or most optimum. It is sometimes difficult to forecast directions of the displacements. In that case, the minimum detectable displacements in a geodetic monitoring network are derived on the eigen-directions associated with the maximum eigen-values of the network stations. This study investigates how minimum detectable displacements in a GNSS monitoring network change depending on the accuracies of the network stations. For this, CORS-TR network in Turkey with 15 stations (a station fixed) is used. The data with 4h, 6h, 12 h and 24 h observing session duration in three sequential days of 2011, 2012 and 2013 were analyzed with Bernese 5.2 GNSS software. The repeatabilities of the daily solutions belonging to each year were analyzed carefully to scale the Bernese cofactor matrices properly. The root mean square (RMS) values for daily repeatability with respect to the combined 3-day solution are computed (the RMS values are generally less than 2 mm in the horizontal directions (north and east) and < 5 mm in the vertical direction for 24 h observing session duration). With the obtained cofactor matrices for these observing sessions, the minimum detectable displacements along the (maximum) eigen directions are compared each other. According to these comparisons, more session duration less minimum detectable

  6. Comparison of Proportional Assist Ventilation Plus, T-Tube Ventilation, and Pressure Support Ventilation as Spontaneous Breathing Trials for Extubation: A Randomized Study.

    PubMed

    Teixeira, Sandy Nogueira; Osaku, Erica Fernanda; Costa, Claudia Rejane Lima de Macedo; Toccolini, Beatriz Fernandes; Costa, Nicolle Lamberti; Cândia, Maria Fernanda; Leite, Marcela Aparecida; Jorge, Amaury Cezar; Duarte, Péricles Almeida Delfino

    2015-11-01

    Failure to wean can prolong ICU stay, increase complications associated with mechanical ventilation, and increase morbidity and mortality. The spontaneous breathing trial (SBT) is one method used to assess weaning. The aim of this study was to assess proportional assist ventilation plus (PAV+) as an SBT by comparing its applicability, safety, and efficacy with T-tube and pressure support ventilation (PSV). A randomized study was performed involving 160 adult subjects who remained on mechanical ventilation for > 24 h. Subjects were randomly assigned to the PAV+, PSV, or T-tube group. When subjects were ready to perform the SBT, subjects in the PAV+ group were ventilated in PAV+ mode (receiving support of up to 40%), the pressure support was reduced to 7 cm H2O in the PSV group, and subjects in the T-tube group were connected to one T-piece with supplemental oxygen. Subjects were observed for signs of intolerance, whereupon the trial was interrupted. When the trial succeeded, the subjects were extubated and assessed until discharge. The subjects were predominantly male (66.5%), and the leading cause of admission was traumatic brain injury. The groups were similar with respect to baseline characteristics, and no significant difference was observed among the groups regarding extubation success or failure. Analysis of the specificity and sensitivity revealed good sensitivity for all groups; however, the PAV+ group had higher specificity (66.6%) and higher sensitivity (97.6%), with prediction of ∼ 92.1% of the success and failure events. No significant differences in the groups was observed regarding the rate of extubation failure, duration of mechanical ventilation, and ICU and hospital stay, indicating that PAV+ is an alternative for use as an SBT. Copyright © 2015 by Daedalus Enterprises.

  7. 46 CFR 153.312 - Ventilation system standards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... ventilation system must be sized to change the air in the ventilated space at least 30 times per hour. (f) A... 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...

  8. Fire Service Training. Ventilation. (Revised).

    ERIC Educational Resources Information Center

    North Carolina State Dept. of Community Colleges, Raleigh.

    One of a set of fourteen outlines for use in a course to train novice firemen, this guide covers ventilation practices and principles. As background, subjects such as heat transmission and building construction are included. The three objectives of this part of the course are to enable the fireman to (1) rescue trapped victims, (2) locate fires as…

  9. Preventing Ventilation On Sailboard Skegs

    NASA Technical Reports Server (NTRS)

    Caldwell, Richard A.

    1990-01-01

    Design effort undertaken to solve spinout problem plaguing high-performance sailboards. Proposed skeg section designed by use of computer model of pressure field and boundary layer. Prevents ventilation by maintaining attached boundary-layer flow throughout operating environment. Cavitation also avoided by preventing valleys in pressure distribution while skeg operated throughout its range.

  10. Preventing Ventilation On Sailboard Skegs

    NASA Technical Reports Server (NTRS)

    Caldwell, Richard A.

    1990-01-01

    Design effort undertaken to solve spinout problem plaguing high-performance sailboards. Proposed skeg section designed by use of computer model of pressure field and boundary layer. Prevents ventilation by maintaining attached boundary-layer flow throughout operating environment. Cavitation also avoided by preventing valleys in pressure distribution while skeg operated throughout its range.

  11. Prognosis of mechanically ventilated patients.

    PubMed Central

    Papadakis, M A; Lee, K K; Browner, W S; Kent, D L; Matchar, D B; Kagawa, M K; Hallenbeck, J; Lee, D; Onishi, R; Charles, G

    1993-01-01

    In this Department of Veterans Affairs cooperative study, we examined predictors of in-hospital and 1-year mortality of 612 mechanically ventilated patients from 6 medical intensive care units in a retrospective cohort design. The outcome variable was vital status at hospital discharge and after 1 year. The results showed that 97% of patients were men, the mean age was 63 +/- 11 years (SD), and hospital mortality was 64% (95% confidence interval, 60% to 68%). Within the next year, an additional 38% of hospital survivors died, for a total 1-year mortality of 77% (95% confidence interval, 73% to 80%). Hospital and 1-year mortality, respectively, for patients older than 70 years was 76% and 94%, for those with serum albumin levels below 20 grams per liter it was 92% and 96%, for those with an Acute Physiology and Chronic Health Evaluation II (APACHE II) score greater than 35 it was 91% and 98%, and for patients who were being mechanically ventilated after cardiopulmonary resuscitation it was 86% and 90%. The mortality ratio (actual mortality versus APACHE II-predicted mortality) was 1.15. Conclusions are that patient age, APACHE II score, serum albumin levels, or the use of cardiopulmonary resuscitation may identify a subset of mechanically ventilated veterans for whom mechanical ventilation provides little or no benefit. PMID:8128673

  12. Evaluation of four-dimensional computed tomography (4D-CT)-based pulmonary ventilation: The high correlation between 4D-CT ventilation and (81m)Kr-planar images was found.

    PubMed

    Kanai, Takayuki; Kadoya, Noriyuki; Ito, Kengo; Kishi, Kazuma; Dobashi, Suguru; Yamamoto, Takaya; Umezawa, Rei; Matsushita, Haruo; Takeda, Ken; Jingu, Keiichi

    2016-06-01

    To evaluate four-dimensional computed tomography (4D-CT)-derived pulmonary ventilation by comparing with (81m)Kr-gas ventilation (VRI). We also proposed two methods to improve the functional accuracy of 4D-CT ventilation images and evaluated these methods. Eleven lung cancer patients with 4D-CT and VRI were analyzed. Hounsfield unit-based (VHU) and a Jacobian-based (VJac) 4D-CT ventilation images were calculated. They were evaluated by voxel-by-voxel spearman's rank correlation coefficient (r) between 4D-CT ventilation and VRI images. After applying an averaging ventilation method and a slope calculating method, correlations were also calculated. 4D-CT ventilation showed the high correlation to VRI (r=0.875 with VHU). An averaging method brought significantly higher (p=0.012) correlations to nuclear medicine images with VHU. The improvement was not significant (p=0.619) with VJac. Slope calculating method improved the correlation with VHU and slightly worsened the correlation with VJac. The averaging method we proposed might be useful to improve 4D-CT ventilation images. We found good agreement between 4D-CT ventilation and nuclear medicine ventilation, indicating the high physiologic accuracy of 4D-CT ventilation. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. Helium vs. Proton Induced Displacement Damage in Electronic Materials

    NASA Technical Reports Server (NTRS)

    Ringo, Sawnese; Barghouty, A. F.

    2010-01-01

    In this project, the specific effects of displacement damage due to the passage of protons and helium nuclei on some typical electronic materials will be evaluated and contrasted. As the electronic material absorbs the energetic proton and helium momentum, degradation of performance occurs, eventually leading to overall failure. Helium nuclei traveling at the same speed as protons are expected to impart more to the material displacement damage; due to the larger mass, and thus momentum, of helium nuclei compared to protons. Damage due to displacement of atoms in their crystalline structure can change the physical properties and hence performance of the electronic materials.

  14. Speed of collapse of the non-ventilated lung during single-lung ventilation for thoracoscopic surgery: the effect of transient increases in pleural pressure on the venting of gas from the non-ventilated lung.

    PubMed

    Pfitzner, J; Peacock, M J; Harris, R J

    2001-10-01

    A study of 10 anaesthetised patients placed in the lateral position for thoracoscopic surgery assessed whether transient increases in pleural pressure on the side of the non-ventilated lung might increase the speed at which gas vents from that lung. The transient increases in pleural pressure were generated by the mediastinal displacement that occurs with each inspiratory phase of positive pressure ventilation of the dependent lung. When combined with a unidirectional valve allowing gas to flow out of the non-ventilated lung, and a second valve allowing ambient airflow into, but not out of, the thoracic cavity via an initial thoracoscopy access site, this mediastinal displacement could conceivably serve to 'pump' gas out of the non-ventilated lung. Using the four different combinations of valve inclusion or omission, the volume of gas that vented from the non-ventilated lung into a measuring spirometer was recorded during a 120-s measurement sequence. It was found that the speed of venting was not increased by the transient increases in pleural pressure, and that in all but one of a total of 34 measurement sequences, venting had ceased by the end of the sequence. Gas venting was a mean (SD) of 85.5 (11.9)% complete in 25 s (five breaths), and 96.6 (6.1)% complete in 60 s. This prompt partial lung collapse very likely reflected the passive elastic recoil of the lung, while the failure of transient increases in pleural pressure to result in ongoing venting of gas was probably a consequence of airways closure as the lung collapsed. It is concluded that techniques that aim to speed lung collapse by increasing pleural pressure are unlikely to be effective.

  15. Infiltration Effects on Residential Pollutant Concentrations for Continuous and Intermittent Mechanical Ventilation Approaches

    SciTech Connect

    Sherman, Max; Logue, Jennifer; Singer, Brett

    2010-06-01

    The prevailing residential ventilation standard in North America, American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 62.2, specifies volumetric airflow requirements as a function of the overall size of the home and the number of bedrooms, assumes a fixed, minimal amount of infiltration, and requires mechanical ventilation to achieve the remainder. The standard allows for infiltration credits and intermittent ventilation patterns that can be shown to provide comparable performance. Whole-house ventilation methods have a substantial effect on time-varying indoor pollutant concentrations. If alternatives specified by Standard 62.2, such as intermittent ventilation, are used, short-term pollutant concentrations could exceed acute health standards even if chronic health standards are met.The authors present a methodology for comparing ASHRAE- and non-ASHRAE-specified ventilation scenarios on relative indoor pollutant concentrations. We use numerical modeling to compare the maximum time-averaged concentrations for acute exposure relevant (1-hour, 8-hour, 24-hour ) and chronic exposure relevant (1-year) time periods for four different ventilation scenarios in six climates with a range of normalized leakage values. The results suggest that long-term concentrations are the most important metric for assessing the effectiveness of whole-house ventilation systems in meeting exposure standards and that, if chronic health exposure standards are met, acute standards will also be met.

  16. Effect of unilateral breathing exercises on regional lung ventilation.

    PubMed

    Tucker, B; Jenkins, S; Cheong, D; Robinson, P

    1999-09-01

    We investigated the effect of a unilateral thoracic expansion exercise (TEE), a breathing manoeuvre used by physiotherapists, on regional lung ventilation. Nine trained physiotherapists aged 22-37 years completed the study. Technegas lung ventilation scans were used to determine the effect of a right unilateral TEE performed when sitting. This was compared with a maximal deep breath. Total radioactivity in each lung was determined. Each lung was sectioned into three equal zones (upper, middle and lower) and the ratio of radioactivity for each of the corresponding lung zones calculated. Ventilation was preferentially distributed to the right lung in all participants during both breathing manoeuvres. The mean (+/- S.E.M.) radioactivity ratios (right/left lung) were greater during a unilateral TEE (1.17 +/- 0.02) than during a deep breath (1.07 +/- 0.01). Seven participants achieved significantly greater ventilation to the right middle (1.15 +/- 0.03, P = 0.02) and lower zones (1.34 +/- 0.03, P = 0.02) during a unilateral TEE than to the corresponding zones on the left; this was evident soon after the initiation of the breath. The findings of this study show that relative regional ventilation to the ipsilateral lung can be increased during a unilateral TEE in trained individuals.

  17. Study of North Atlantic ventilation using transient tracers. Doctoral Thesis

    SciTech Connect

    Doney, S.C.

    1991-08-01

    Tritium, (3)He, and chlorofluorocarbon distributions in the North Atlantic provide constraints on the ventilation time-scales for the thermocline and abyssal water. A new model function based on a factor analysis of the WMO/IAEA precipitation data set is developed for predicting the spatial and temporal patterns of bomb-tritium in precipitation. Model atmospheric and advective tri