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Sample records for refereeris peep kngas

  1. Pop Culture Peeps

    ERIC Educational Resources Information Center

    Kruszewski, Julie; Fontes, Kris

    2008-01-01

    In this article, the authors present a classroom activity called Pop Culture Peep. In this particular activity, students are required to first research famous artists and/or famous artworks to have an image to use as a reference. Students then plan out how they would decorate the Peep, deciding what materials they would use to create the Peep in…

  2. Recruitment Maneuvers and PEEP Titration.

    PubMed

    Hess, Dean R

    2015-11-01

    The injurious effects of alveolar overdistention are well accepted, and there is little debate regarding the importance of pressure and volume limitation during mechanical ventilation. The role of recruitment maneuvers is more controversial. Alveolar recruitment is desirable if it can be achieved, but the potential for recruitment is variable among patients with ARDS. A stepwise recruitment maneuver, similar to an incremental PEEP titration, is favored over sustained inflation recruitment maneuvers. Many approaches to PEEP titration have been proposed, and the best method to choose the most appropriate level for an individual patient is unclear. A PEEP level should be selected that balances alveolar recruitment against overdistention. The easiest approach to select PEEP might be according to the severity of the disease: 5-10 cm H2O PEEP in mild ARDS, 10-15 cm H2O PEEP in moderate ARDS, and 15-20 cm H2O PEEP in severe ARDS. Recruitment maneuvers and PEEP should be used within the context of lung protection and not just as a means of improving oxygenation. PMID:26493593

  3. Peeps at William Edwin Hamilton

    NASA Astrophysics Data System (ADS)

    Wayman, P. A.

    1999-01-01

    William Edwin Hamilton, 1834-1902, (WEH) was the elder son of Sir William Rowan Hamilton and Helen Hamilton and he inherited many of the characteristics of his famous father. One property that he did not inherit, however, was his father's genius. While the outline of the life of WEH was given by Hankins in his 1980 biography of Sir William, a copy of ``Peeps at My Life'' written by WEH during the last months of his life was not available until recently. A few years ago a copy was sent to me by Herman Berg of Detroit and in this article, the principal items in ``Peeps'' that are relevant to Ireland, and some other facets of the character of WEH, are included as they give an unusual viewpoint of a by-gone age.

  4. PEEP Annual Report, April 1999-March 2000.

    ERIC Educational Resources Information Center

    Peers Early Education Partnership, Oxford (England).

    The goal of England's Peers Early Education Partnership (PEEP) is to support early communication and literacy skills and to support parents as their children's first educators through both home- and group-based programs. The program is currently offered to all children under 5 years of age and their families in a disadvantaged area of Oxford. This…

  5. PEEP Annual Report, April 2001-March 2002.

    ERIC Educational Resources Information Center

    Peers Early Education Partnership, Oxford (England).

    The goal of England's Peers Early Education Partnership (PEEP) is to support early communication and literacy skills and to support parents as their children's first educators through both home- and group-based programs. The program is currently offered to children under 5 years of age and their families in a disadvantaged area of Oxford. This…

  6. PEEP Annual Report, April 2000-March 2001.

    ERIC Educational Resources Information Center

    Peers Early Education Partnership, Oxford (England).

    The goal of England's Peers Early Education Partnership (PEEP) is to support early communication and literacy skills and to support parents as their children's first educators through both home- and group-based programs. The program is currently offered to children under 5 years of age and their families in a disadvantaged area of Oxford. This…

  7. PEEP Annual Report, 1997-1998.

    ERIC Educational Resources Information Center

    Peers Early Education Partnership, Oxford (England).

    The goal of England's PEERS Early Education Partnership (PEEP) is to support early communication and literacy skills and to support parents as their children's first educators through both home- and group-based programs. The program is offered to children under 5 and their families in a disadvantaged area of Oxford, England. This report describes…

  8. PEEP Management Team Report, April 1998-March 1999.

    ERIC Educational Resources Information Center

    Peers Early Education Partnership, Oxford (England).

    The Peers Early Education Partnership (PEEP) program was established in 1995 to make a significant long-term positive impact on the educational attainment of children and families in disadvantaged areas of the United Kingdom. This report examines the work of the PEEP program for the period April 1998 through March 1999. The sections of the…

  9. A decremental PEEP trial for determining open-lung PEEP in a rabbit model of acute lung injury.

    PubMed

    Hua, Yi-Ming; Lien, Shao-Hung; Liu, Tao-Yuan; Lee, Chuen-Ming; Yuh, Yeong-Seng

    2008-04-01

    A positive end-expiratory pressure (PEEP) above the lower inflection point (LIP) of the pressure-volume curve has been thought necessary to maintain recruited lung volume in acute lung injury (ALI). We used a strategy to identify the level of open-lung PEEP (OLP) by detecting the maximum tidal compliance during a decremental PEEP trial (DPT). We performed a randomized controlled study to compare the effect of the OLP to PEEP above LIP and zero PEEP on pulmonary mechanics, gas exchange, hemodynamic change, and lung injury in 26 rabbits with ALI. After recruitment maneuver, the lavage-injured rabbits received DPTs to identify the OLP. Animals were randomized to receive volume controlled ventilation with either: (a) PEEP = 0 cm H2O (ZEEP); (b) PEEP = 2 cm H2O above OLP (OLP + 2); or (c) PEEP = 2 cm H2O above LIP (LIP + 2). Peak inspiratory pressure and mean airway pressure were recorded and arterial blood gases were analyzed every 30 min. Mean blood pressure and heart rate were monitored continuously. Lung injury severity was assessed by lung wet/dry weight ratio. Animals in OLP + 2 group had less lung injury as well as relatively better compliance, more stable pH, and less hypercapnia compared to the LIP + 2 and ZEEP groups. We concluded that setting PEEP according to the OLP identified by DPTs is an effective method to attenuate lung injury. This strategy could be used as an indicator for optimal PEEP. The approach is simple and noninvasive and may be of clinical interest. PMID:18293413

  10. Detection of optimal PEEP for equal distribution of tidal volume by volumetric capnography and electrical impedance tomography during decreasing levels of PEEP in post cardiac-surgery patients

    PubMed Central

    Blankman, P.; Shono, A.; Hermans, B. J. M.; Wesselius, T.; Hasan, D.; Gommers, D.

    2016-01-01

    Background Homogeneous ventilation is important for prevention of ventilator-induced lung injury. Electrical impedance tomography (EIT) has been used to identify optimal PEEP by detection of homogenous ventilation in non-dependent and dependent lung regions. We aimed to compare the ability of volumetric capnography and EIT in detecting homogenous ventilation between these lung regions. Methods Fifteen mechanically-ventilated patients after cardiac surgery were studied. Ventilator settings were adjusted to volume-controlled mode with a fixed tidal volume (Vt) of 6–8 ml kg−1 predicted body weight. Different PEEP levels were applied (14 to 0 cm H2O, in steps of 2 cm H2O) and blood gases, Vcap and EIT were measured. Results Tidal impedance variation of the non-dependent region was highest at 6 cm H2O PEEP, and decreased significantly at 14 cm H2O PEEP indicating decrease in the fraction of Vt in this region. At 12 cm H2O PEEP, homogenous ventilation was seen between both lung regions. Bohr and Enghoff dead space calculations decreased from a PEEP of 10 cm H2O. Alveolar dead space divided by alveolar Vt decreased at PEEP levels ≤6 cm H2O. The normalized slope of phase III significantly changed at PEEP levels ≤4 cm H2O. Airway dead space was higher at higher PEEP levels and decreased at the lower PEEP levels. Conclusions In postoperative cardiac patients, calculated dead space agreed well with EIT to detect the optimal PEEP for an equal distribution of inspired volume, amongst non-dependent and dependent lung regions. Airway dead space reduces at decreasing PEEP levels. PMID:27199318

  11. The Crazy Business of Internet Peeping, Privacy, and Anonymity.

    ERIC Educational Resources Information Center

    Van Horn, Royal

    2000-01-01

    Peeping software takes several forms and can be used on a network or to monitor a certain computer. E-Mail Plus, for example, hides inside a computer and sends exact copies of incoming or outgoing e-mail anywhere. School staff with monitored computers should demand e-mail privacy. (MLH)

  12. PEEP Voices: A Five Year Diary. Supporting Early Learning at Home, 1995-2000.

    ERIC Educational Resources Information Center

    Roberts, Rosemary, Ed.

    The Peers Early Education Partnership (PEEP) has been in operation in Oxford, England for 5 years, with the aim of raising educational attainment, especially in literacy, by an entire community of children from their birth. This book recounts how PEEP started and its operation over the 5 years, focusing on the impact of the program and the…

  13. Hyperdynamic sepsis modifies a PEEP-mediated redistribution in organ blood flows

    SciTech Connect

    Bersten, A.D.; Gnidec, A.A.; Rutledge, F.S.; Sibbald, W.J. )

    1990-05-01

    Changes in organ blood flow (Q) produced by 20 cm H2O positive end-expiratory pressure (PEEP) were measured before and after the induction of hyperdynamic sepsis in nine unanesthetized sheep. During the baseline nonseptic study, PEEP was associated with a 9% fall in thermodilution-measured systemic Q, although arterial perfusing pressures were unaffected. Concurrently, microsphere-derived Q was maintained to the brain and heart, but fell to liver, spleen, pancreas, kidney, large intestine, and gastrocnemius. Twenty-four to 36 h after cecal ligation and perforation, a pre-PEEP septic study demonstrated an increase in all of the cardiac index (CI) and systemic O2 delivery when compared with the nonseptic study, whereas whole-body O2 extraction was depressed. Although PEEP depressed systemic Q during the septic study to a greater extent than during the nonseptic study (p less than 0.02), absolute organ Q fell only to pancreas, liver, and spleen. Relative to the simultaneous fall in the CI, Q to some splanchnic organs was not depressed by PEEP to the same magnitude in the septic as in the nonseptic study. When an infusion of Ringer's lactate subsequently restored systemic Q to pre-PEEP septic levels, individual flows that had been depressed by PEEP were not restored. Furthermore, Q-kidney continued to fall, such that the postfluid Q-kidney (-19%) was significantly less than was demonstrated in the pre-PEEP septic study. We postulate that differences noted in the distribution of organ Q between the nonseptic and hyperdynamic septic studies after the application of PEEP were secondary to the vasculopathy of sepsis and/or an alteration in the function of specific organ microcirculations. However, these data do not address whether the changes in organ Q distribution after a PEEP-mediated depression in systemic Q during sepsis significantly restricted tissue DO2.

  14. [Postural therapy during mechanical pulmonary ventilation with PEEP in patients with unilateral lung damage].

    PubMed

    Neverin, V K; Vlasenko, A V; Mitrokhin, A A; Galushka, S V; Ostapchenko, D V; Shishkina, E V

    2000-01-01

    Mechanical ventilation of the lungs (MVL) with positive end expiratory pressure (PEEP) is difficult in patients with unilateral lung damage because of uneven distribution of volumes and pressures in the involved and intact lungs. Harmful effects are easier manifested under such conditions. Selective MVL with selective PEEP is widely used abroad for optimizing MVL, but this method is rather expensive and is not devoid of shortcomings. Our study carried out in 32 patients with unilateral lung involvement showed that traditional MVL with general PEEP can effectively (in 75% cases) regulate gaseous exchange and decrease its untoward effects if MVL is performed with the patient lying on the healthy side and not supine. MVL in patients with unilateral lung injury lying on the healthy side can be a simpler and cheaper alternative to selective MVL with selective PEEP. PMID:10833838

  15. Should PEEP Titration Be Based on Chest Mechanics in Patients With ARDS?

    PubMed

    Kallet, Richard H

    2016-06-01

    Functional residual capacity (FRC) is essentially the alveolar volume and a determinant of both oxygenation and respiratory system compliance (CRS). ARDS decreases FRC, and sufficient PEEP restores FRC; thus, assessments of PEEP by its impact on oxygenation and CRS are intimately linked. PEEP also can ameliorate or aggravate ventilator-induced lung injury. Therefore, it can be argued that PEEP should be titrated primarily by its impact on CRS The pro position argues that the heterogeneous nature of lung injury and its unique presentation in individual patients results in an uncoupling between oxygenation and CRS Therefore, relying upon oxygenation alone may enhance lung injury and mortality risk, particularly in those with severe ARDS. The con argument is that the preponderance of preclinical and clinical evidence suggests that a relatively narrow range of PEEP is required to manage all but the most severe cases of ARDS. In addition, pathological alterations in chest wall compliance confuse the interpretation of chest mechanics. Moreover, ambiguities and technical limitations in advanced techniques, such as esophageal manometry and pressure-volume curves, add a layer of complexity that renders its broader application in all ARDS patients both impractical and unnecessary. Whether sophisticated monitoring of chest mechanics in severe ARDS might improve outcomes further is open to question and should be studied further. However, it is highly improbable that we will ever discover a PEEP strategy that optimizes all aspects of cardiorespiratory function and chest mechanics for individual patients suffering from ARDS. PMID:27235320

  16. Moderate Peep After Tracheal Lipopolysaccharide Instillation Prevents Inflammation and Modifies the Pattern of Brain Neuronal Activation

    PubMed Central

    Quilez, María Elisa; Rodríguez-González, Raquel; Turon, Marc; Fernandez-Gonzalo, Sol; Villar, Jesús; Kacmarek, Robert M.; Gómez, Ma Nieves; Oliva, Joan Carles; Blanch, Lluís; López-Aguilar, Josefina

    2015-01-01

    ABSTRACT Background: Ventilatory strategy and specifically positive end-expiratory pressure (PEEP) can modulate the inflammatory response and pulmonary-to-systemic translocation of lipopolysaccharide (LPS). Both inflammation and ventilatory pattern may modify brain activation, possibly worsening the patient's outcome and resulting in cognitive sequelae. Methods: We prospectively studied Sprague–Dawley rats randomly assigned to undergo 3 h mechanical ventilation with 7 mL/kg tidal ventilation and either 2 cmH2O or 7 cmH2O PEEP after intratracheal instillation of LPS or saline. Healthy nonventilated rats served as baseline. We analyzed lung mechanics, gas exchange, lung and plasma cytokine levels, lung apoptotic cells, and lung neutrophil infiltration. To evaluate brain neuronal activation, we counted c-Fos immunopositive cells in the retrosplenial cortex (RS), thalamus, supraoptic nucleus (SON), nucleus of the solitary tract (NTS), paraventricular nucleus (PVN), and central amygdala (CeA). Results: LPS increased lung neutrophilic infiltration, lung and systemic MCP-1 levels, and neuronal activation in the CeA and NTS. LPS-instilled rats receiving 7 cmH2O PEEP had less lung and systemic inflammation and more c-Fos-immunopositive cells in the RS, SON, and thalamus than those receiving 2 cmH2O PEEP. Applying 7 cmH2O PEEP increased neuronal activation in the CeA and NTS in saline-instilled rats, but not in LPS-instilled rats. Conclusions: Moderate PEEP prevented lung and systemic inflammation secondary to intratracheal LPS instillation. PEEP also modified the neuronal activation pattern in the RS, SON, and thalamus. The relevance of these differential brain c-Fos expression patterns in neurocognitive outcomes should be explored. PMID:26398809

  17. Effect of inspiratory resistance and PEEP on /sup 99m/Tc-DTPA clearance

    SciTech Connect

    O'Brodovich, H.; Coates, G.; Marrin, M.

    1986-05-01

    Experiments were performed to determine the effect of markedly negative pleural pressure (Ppl) or positive end-expiratory pressure (PEEP) on the pulmonary clearance (k) of technetium-99m-labeled diethylenetriaminepentaacetic acid (/sup 99m/Tc-DTPA). A submicronic aerosol containing /sup 99m/Tc-DTPA was insufflated into the lungs of anesthetized intubated sheep. In six experiments k was 0.44 +/- 0.46% (SD)/min during the initial 30 min and was unchanged during the subsequent 30-min interval (k = 0.21 +/- 12%/min) when there was markedly increased inspiratory resistance. A 3-mm-diam orifice in the inspiratory tubing created the resistance. It resulted on average in a 13-cmH2O decrease in inspiratory Ppl. In eight additional experiments sheep were exposed to 2, 10, and 15 cmH2O PEEP (20 min at each level). During 2 cmH2O PEEP k = 0.47 +/- 0.15%/min, and clearance increased slightly at 10 cmH2O PEEP (0.76 +/- 0.28%/min, P less than 0.01). When PEEP was increased to 15 cmH2O a marked increase in clearance occurred (k = 1.95 +/- 1.08%/min, P less than 0.001). The experiments demonstrate that markedly negative inspiratory pressures do not accelerate the clearance of /sup 99m/Tc-DTPA from normal lungs. The effect of PEEP on k is nonlinear, with large effects being seen only with very large increases in PEEP.

  18. Unusual case of acute tracheal injury complicated by application of positive end expiratory pressure (PEEP).

    PubMed

    Farooqui, Asif Masroor; Mbarushimana, Simon; Faheem, Mohammad

    2014-01-01

    Blunt neck trauma can be caused by a variety of injuries such as deceleration, road traffic accidents and crush injuries. The worst scenario is airway rupture. We report an unusual case of acute tracheal injury in a 34-year-old Irish man who presented with a history of strangulation while working with a tractor. On arrival, he had one episode of mild haemoptysis and reported pain around the base of the neck and voice hoarseness. His chest X-ray revealed pneumopericardium and CT of thorax showed airway oedema. After elective intubation, positive end-expiratory pressure (PEEP) of 5 cm H2O caused deterioration in his clinical condition with increasing surgical emphysema and rise of carbon dioxide partial pressure (PaCO2), which was completely reversed after stopping PEEP. This case shows how PEEP and intermittent positive pressure ventilation can worsen air leak and compromise stability in patients with acute tracheal injury. PMID:25398917

  19. PEEP therapy for patients with pleurotomy during coronary artery bypass grafting.

    PubMed

    Ishikawa, S; Ohtaki, A; Takahashi, T; Sakata, K; Koyano, T; Kano, M; Ohki, S; Kawashima, O; Hamada, Y; Morishita, Y

    2000-01-01

    Severe pulmonary oxygenation impairment resulting from peripheral lung atelectasis occurred in some patients with pleurotomy during the harvest of the internal mammary artery graft followed by coronary artery bypass grafting (CABG). We studied the efficacy of intraoperative positive end-expiratory airway pressure (PEEP) therapy for the prevention of postoperative pulmonary oxygenation impairment. A total of 66 patients with solitary CABG procedure were included in this study. The pleural cavity was intraoperatively opened in 44 patients and not opened in 22. PEEP therapy was not used in any patient before May 1996 (referred to herein as the former period) and was used more recently in eight patients with pleurotopmy (referred to herein as the latter period). PEEP was initiated immediately after pleurotomy during the harvest of the internal mammary artery graft. Without PEEP therapy, values of PaO2, A-aDO2, and respiratory index (RI) were worse in patients with pleurotomy than in those without pleurotomy. Meanwhile, there were no major differences in these values between patients with or without pleurotomy after the induction of PEEP therapy. Respiratory insufficiency (A-aDO2 > 400 mmHg and RI > 1.5) was detected in six patients with pleurotomy in the former period. Three of these six patients required over 1 week of long-term mechanical respiratory support. No respiratory insufficiency occurred in patients of the latter period. In conclusion, PEEP therapy, which is initiated just after pleurotomy, may prevent oxygen impairment and pulmonary atelectasis after extracorporeal circulation (ECC) and is recommended for patients with pleurotomy, especially for patients with preoperative low respiratory function. PMID:11414602

  20. Effect of PEEP on regional ventilation and perfusion in the mechanically ventilated preterm lamb

    SciTech Connect

    Schlessel, J.S.; Susskind, H.; Joel, D.D.; Bossuyt, A.; Harrold, W.H.; Zanzi, I.; Chanana, A.D. )

    1989-08-01

    Improvement of gas exchange through closer matching of regional ventilation (V) and lung perfusion (Q) with the application of positive end-expiratory pressure (PEEP) was evaluated in vivo in six mechanically ventilated preterm lambs (107-126 days/145 days gestation). Changes in V and Q were determined from in vivo scintigraphic measurements in four lung regions with inhaled radioactive 81mKr, and infused {sup 81m}Kr/dextrose and/or ({sup 99m}Tc)MAA as PEEP was applied at 2, 4, and 6 cm H{sub 2}O in each animal. Dynamic compliance varied between 0.02 and 0.40 ml/cm H{sub 2}O, which was consistent with surfactant deficiency. As PEEP was increased, the regional distribution of Q shifted from the rostral to the caudal lung regions (p less than 0.02 to less than 0.05), while that of V remained unchanged. Regional V/Q matching improved together with a trend towards improvement of arterial blood gases as PEEP was increased from 2 to 4 cm H{sub 2}O. Pulmonary scintigraphy offers a noninvasive methodology for the quantitative assessment of regional V and Q matching in preterm lambs and may be clinically applicable to ventilated neonates.

  1. Fluvial Erosion Measurements of Streambank Using Photo-Electronic Erosion Pins (peep)

    NASA Astrophysics Data System (ADS)

    Sutarto, T.; Papanicolaou, T.; Wilson, C. G.; Bertrand, F.

    2010-12-01

    Cohesive streambank erosion is characterized by two main mechanisms, fluvial entrainment of individual particles and bank failure due to gravity (Thorne, 1980). In this study, the relative importance of fluvial erosion (compared to mass failure) was determined in two reaches from different locations of the Clear Creek Watershed (CCW). The main goal of the project was the identification of the key erosion process at each site. Beyond the distinguished flow conditions (hydraulic forces), different stream orders, and land-use, no further attempts were made to identify other key driving agents behind the erosion, such subaerial processes (e.g., seepage, freeze/thaw) acting at the cohesive riverbanks (Lindow et al., 2009). Erosion lengths up to 38 cm were detected. The bank erosion monitoring at high resolution intervals due to the PEEPS allowed for better characterization the fluvial erosion occurring at this site and develop a correspondence between sedigraphs and hydrographs. .Similar statistical methods were used at both sites to support our findings. The moving average identified the dominant trend of the data and the variability of the erosion lengths at the two sites. Further, the use of the Shewhart Charts allowed us to detect the critical erosion events during the period of observation. Finally the overall performance of the PEEPs was evaluated during this study. A correlation analysis was conducted between the direct measurements of traditional methods (e.g., erosion pins, geodetical surveys, measure tape) and the automated data recorded by the PEEP. The maximum error between manual and automated measurements of the exposed length of the PEEPs was less than 27%. The error between the channel survey and the automated PEEP measurements was less than 14%.

  2. Temporal hemodynamic effects of permissive hypercapnia associated with ideal PEEP in ARDS.

    PubMed

    Carvalho, C R; Barbas, C S; Medeiros, D M; Magaldi, R B; Lorenzi Filho, G; Kairalla, R A; Deheinzelin, D; Munhoz, C; Kaufmann, M; Ferreira, M; Takagaki, T Y; Amato, M B

    1997-11-01

    The associated use of permissive hypercapnia (PHY) and high PEEP levels (PEEP(IDEAL)) has been recently indicated as part of a lung-protective-approach (LPA) in acute respiratory distress syndrome (ARDS). However, the net hemodynamic effect produced by this association is not known. We analyzed the temporal hemodynamic effects of this combined strategy in 48 patients (mean age 34 +/- 13 yr) with ARDS, focusing on its immediate (after 1 h), early (first 36 h), and late (2nd-7th d) consequences. Twenty-five patients were submitted to LPA--with the combined use of permissive hypercapnia (PHY), VT < 6 ml/kg, distending pressures above PEEP < 20 cm H2O, and PEEP 2 cm H2O above the lower inflection point on the static inspiratory P-V curve (P(FLEX))- and 23 control patients were submitted to conventional mechanical ventilation. LPA was initiated at once, resulting in an immediate increase in heart rate (p = 0.0002), cardiac output (p = 0.0002), oxygen delivery (DO2l, p = 0.0003), and mixed venous Po2 (p = 0.0006), with a maintained systemic oxygen consumption (p = 0.52). The mean pulmonary arterial pressure markedly increased (mean increment 8.8 mm Hg; p < 0.0001), but the pulmonary vascular resistance did not change (p = 0.32). Cardiac filling pressures increased (p < 0.001) and the systemic vascular resistance fell (p = 0.003). All these alterations were progressively attenuated in the course of the first 36 h, despite persisting hypercapnia. Plasma lactate suffered a progressive decrement along the early period in LPA but not in control patients (p < 0.0001). No hemodynamic consequences of LPA were noticed in the late period and renal function was preserved. A multivariate analysis suggested that these acute hyperdynamic effects were related to respiratory acidosis, with no depressant effects ascribed to high PEEP levels. In contrast, high plateau pressures were associated with cardiovascular depression. Thus, as long as sufficiently low distending pressures are

  3. Electrical Impedance Tomography-guided PEEP Titration in Patients Undergoing Laparoscopic Abdominal Surgery.

    PubMed

    He, Xingying; Jiang, Jingjing; Liu, Yuli; Xu, Haitao; Zhou, Shuangqiong; Yang, Shibo; Shi, Xueyin; Yuan, Hongbin

    2016-04-01

    The aim of the study is to utilize electrical impedance tomography (EIT) to guide positive end-expiratory pressure (PEEP) and to optimize oxygenation in patients undergoing laparoscopic abdominal surgery.Fifty patients were randomly assigned to the control (C) group and the EIT (E) group (n = 25 each). We set the fraction of inspired oxygen (FiO2) at 0.30. The PEEP was titrated and increased in a 2-cm H2O stepwise manner, from 6 to 14 cm H2O. Hemodynamic variables, respiratory mechanics, EIT images, analysis of blood gas, and regional cerebral oxygen saturation were recorded. The postoperative pulmonary complications within the first 5 days were also observed.We chose 10 cm H2O and 8 cm H2O as the "ideal" PEEP for the C and the E groups, respectively. EIT-guided PEEP titration led to a more dorsal shift of ventilation. The PaO2/FiO2 ratio in the E group was superior to that in the C group in the pneumoperitoneum period, though the difference was not significant (330 ± 10 vs 305.56 ± 4 mm Hg; P = 0.09). The C group patients experienced 8.7% postoperative pulmonary complications versus 5.3% among the E group patients (relative risk 1.27, 95% confidence interval 0.31-5.3, P = 0.75).Electrical impedance tomography represents a new promising technique that could enable anesthesiologists to assess regional ventilation of the lungs and optimize global oxygenation for patients undergoing laparoscopic abdominal surgery. PMID:27057904

  4. Haemodynamic effects of pressure support and PEEP ventilation by nasal route in patients with stable chronic obstructive pulmonary disease.

    PubMed Central

    Ambrosino, N; Nava, S; Torbicki, A; Riccardi, G; Fracchia, C; Opasich, C; Rampulla, C

    1993-01-01

    BACKGROUND--Intermittent positive pressure ventilation applied through a nasal mask has been shown to be useful in the treatment of chronic respiratory insufficiency. Pressure support ventilation is an assisted mode of ventilation which is being increasingly used. Invasive ventilation with intermittent positive pressure, with or without positive end expiratory pressure (PEEP), has been found to affect venous return and cardiac output. This study evaluated the acute haemodynamic support ventilation by nasal mask, with and without the application of PEEP, in patients with severe stable chronic obstructive pulmonary disease and hypercapnia. METHODS--Nine patients with severe stable chronic obstructive pulmonary disease performed sessions lasting 10 minutes each of pressure support ventilation by nasal mask while undergoing right heart catheterisation for clinical evaluation. In random order, four sessions of nasal pressure support ventilation were applied consisting of: (1) peak inspiratory pressure (PIP) 10 cm H2O, PEEP 0 cm H2O; (2) PIP 10 cm H2O, PEEP 5 cm H2O; (3) PIP 20 cm H2O, PEEP 0 cm H2O; (4) PIP 20 cm H2O, PEEP 5 cm H2O. RESULTS--Significant increases in arterial oxygen tension (Pao2) and saturation (Sao2) and significant reductions in arterial carbon dioxide tension (PaCO2) and changes in pH were observed with a PIP of 20 cm H2O. Statistical analysis showed that the addition of 5 cm H2O PEEP did not further improve arterial blood gas tensions. Comparison of baseline values with measurements performed after 10 minutes of each session of ventilation showed that all modes of ventilation except PIP 10 cm H2O without PEEP induced a small but significant increase in pulmonary capillary wedge pressure. In comparison with baseline values, a significant decrease in cardiac output and oxygen delivery was induced only by the addition of PEEP to both levels of PIP. CONCLUSIONS--In patients with severe stable chronic obstructive pulmonary disease and hypercapnia

  5. Peep show establishments, police activity, public place, and time: a study of secondary effects in San Diego, California.

    PubMed

    Linz, Daniel; Paul, Bryant; Yao, Mike

    2006-05-01

    An empirical study was undertaken in San Diego, California, to test assumptions made by the government and by conservative religious policy advocates that there is a greater incidence of crime in the vicinity of peep show establishments. We asked two questions: (a) Is criminal activity in San Diego particularly acute at peep show establishments compared to surrounding control locations? and (b) Is criminal activity in San Diego disproportionately greater at or near peep show establishments between the hours of 2 a.m. and 6 a.m. compared to other times of the day? The levels of crime activity and the expenditure of police resources were examined by measuring the number of calls-for-service (CFSs) to the police within a 1,000-ft. area on either side of the peep show establishments and comparably-sized control areas beyond the immediate 1,000-foot area. A more focused late-night (2 a.m. to 6 a.m.) analysis was also undertaken. The results showed no reliable evidence of differences in crime levels between the control and test areas, nor was there any evidence of disproportionately greater amounts of crime within the 2 a.m. to 6 a.m. time period in the areas surrounding the peep show establishments. We concluded that San Diego does not have a problem with crime at the peep show establishments generally, nor is there a heightened problem with crime during the 2 a.m. to 6 a.m. period. We discuss the implications of assuming that peep show establishments are associated with negative effects in the community and the possibility of viewpoint discrimination against sex communication. PMID:16817065

  6. Reliability of Single-Use PEEP-Valves Attached to Self-Inflating Bags during Manual Ventilation of Neonates – An In Vitro Study

    PubMed Central

    Hartung, Julia C.; Wilitzki, Silke; Thio-Lluch, Marta; te Pas, Arjan B.; Schmalisch, Gerd; Roehr, Charles C.

    2016-01-01

    Introduction International resuscitation guidelines suggest to use positive end-expiratory pressure (PEEP) during manual ventilation of neonates. Aim of our study was to test the reliability of self-inflating bags (SIB) with single-use PEEP valves regarding PEEP delivery and the effect of different peak inflation pressures (PIP) and ventilation rates (VR) on the delivered PEEP. Methods Ten new single-use PEEP valves from 5 manufacturers were tested by ventilating an intubated 1kg neonatal manikin containing a lung model with a SIB that was actuated by an electromechanical plunger device. Standard settings: PIP 20cmH2O, VR 60/min, flow 8L/min. PEEP settings of 5 and 10cmH2O were studied. A second test was conducted with settings of PIP 40cmH2O and VR 40/min. The delivered PEEP was measured by a respiratory function monitor (CO2SMO+). Results Valves from one manufacturer delivered no relevant PEEP and were excluded. The remaining valves showed a continuous decay of the delivered pressure during expiration. The median (25th and 75th percentile) delivered PEEP with standard settings was 3.4(2.7–3.8)cmH2O when set to 5cmH2O and 6.1(4.9–7.1)cmH2O when set to 10cmH2O. Increasing the PIP from 20 to 40 cmH2O led to a median (25th and 75th percentile) decrease in PEEP to 2.3(1.8–2.7)cmH2O and 4.3(3.2–4.8)cmH2O; changing VR from 60 to 40/min led to a PEEP decrease to 2.8(2.1–3.3)cmH2O and 5.0(3.5–6.2)cmH2O for both PEEP settings. Conclusion Single-use PEEP valves do not reliably deliver the set PEEP. PIP and VR have an effect on the delivered PEEP. Operators should be aware of these limitations when manually ventilating neonates. PMID:26914209

  7. State of the evidence: mechanical ventilation with PEEP in patients with cardiogenic shock

    PubMed Central

    Wiesen, Jonathan; Ornstein, Moshe; Tonelli, Adriano R; Menon, Venu; Ashton, Rendell W

    2014-01-01

    The need to provide invasive mechanical ventilatory support to patients with myocardial infarction and acute left heart failure is common. Despite the large number of patients requiring mechanical ventilation in this setting, there are remarkably few data addressing the ideal mode of respiratory support in such patients. Although there is near universal acceptance regarding the use of non-invasive positive pressure ventilation in patients with acute pulmonary oedema, there is more concern with invasive positive pressure ventilation owing to its more significant haemodynamic impact. Positive end-expiratory pressure (PEEP) is almost universally applied in mechanically ventilated patients due to benefits in gas exchange, recruitment of alveolar units, counterbalance of hydrostatic forces leading to pulmonary oedema and maintenance of airway patency. The limited available clinical data suggest that a moderate level of PEEP is safe to use in severe left ventricular (LV) dysfunction and cardiogenic shock, and may provide haemodynamic benefits as well in LV failure which exhibits afterload-sensitive physiology. PMID:23539555

  8. Quantifying the roles of tidal volume and PEEP in the pathogenesis of ventilator-induced lung injury.

    PubMed

    Seah, Adrian S; Grant, Kara A; Aliyeva, Minara; Allen, Gilman B; Bates, Jason H T

    2011-05-01

    Management of patients with acute lung injury (ALI) rests on achieving a balance between the gas exchanging benefits of mechanical ventilation and the exacerbation of tissue damage in the form of ventilator-induced lung injury (VILI). Optimizing this balance requires an injury cost function relating injury progression to the measurable pressures, flows, and volumes delivered during mechanical ventilation. With this in mind, we mechanically ventilated naive, anesthetized, paralyzed mice for 4 h using either a low or high tidal volume (Vt) with either moderate or zero positive end-expiratory pressure (PEEP). The derecruitability of the lung was assessed every 15 min in terms of the degree of increase in lung elastance occurring over 3 min following a recruitment maneuver. Mice could be safely ventilated for 4 h with either a high Vt or zero PEEP, but when both conditions were applied simultaneously the lung became increasingly unstable, demonstrating worsening injury. We were able to mimic these data using a computational model of dynamic recruitment and derecruitment that simulates the effects of progressively increasing surface tension at the air-liquid interface, suggesting that the VILI in our animal model progressed via a vicious cycle of alveolar leak, degradation of surfactant function, and increasing tissue stress. We thus propose that the task of ventilating the injured lung is usefully understood in terms of the Vt-PEEP plane. Within this plane, non-injurious combinations of Vt and PEEP lie within a "safe region", the boundaries of which shrink as VILI develops. PMID:21203845

  9. Evidence on Effective Early Childhood Interventions from the United Kingdom: An Evaluation of the Peers Early Education Partnership (PEEP)

    ERIC Educational Resources Information Center

    Evangelou, Maria; Sylva, Kathy

    2007-01-01

    Efforts to improve the educational achievement of children, especially those from disadvantaged backgrounds, are at the heart of current government policies in the United Kingdom. The Peers Early Education Partnership (PEEP) is an intervention that, since 1995, has worked directly with parents and caregivers of children from infancy to 5 years of…

  10. Positive end-expiratory pressure (PEEP) does not depress left ventricular function in patients with pulmonary edema

    SciTech Connect

    Calvin, J.E.; Driedger, A.A.; Sibbald, W.J.

    1981-08-01

    Researchers evaluated the effects of positive end-expiratory pressure (PEEP) on left ventricular function in 15 patients with acute respiratory insufficiency secondary to pulmonary edema with invasive (pressure; flow) measurements and radionuclide angiography (RA). Using RNA allowed a definition of the left ventricular ejection fraction (LVEF), and then calculation of the left ventricular end-diastolic volume (LVEDV), both before and after PEEP. With a mean PEEP of 14.2 +/- 1.8 cm H2O (mean +/- SD) (range, 10 to 15), a fall in the cardiac index (4.34 +/- 1.5 to 3.84 +/- 1.4 L/min/M2; p less than 0.001) was accompanied by a significant decrease in the stroke volume index (42 +/- 13 to 39 +/- 12 ml/beat M2; p less than 0.01) and pulse rate (103.4 +/- 14.3 to 98 +/- 13.5 beats/min; p less than 0.01). The decrease in the stroke volume index was primarily due to a significant decrease in left ventricular preload (LVEDV) from 85.9 +/- 19 to 71.4 +/- 21.4 ml/m2 (p less than 0.01). Simultaneously, the mean LVEF increased from 0.47 +/- 0.10 to 0.53 +/- 0.08 (p less than 0.05), despite a significant increase in the systemic vascular resistance (1,619 +/- 575 to 1,864 +/- 617 dynes . s. cm-5/M2; p less than 0.01). Researchers concluded that the use of PEEP in patients with acute pulmonary edema, to the degree used in this study, may depress cardiac output by simply decreasing left ventricular preload. Researchers were unable to produce any evidence that would support a change in the contractile state of the left ventricle as a cause of depressed forward flow with the use of PEEP.

  11. Worsening Hypoxemia in the Face of Increasing PEEP: A Case of Large Pulmonary Embolism in the Setting of Intracardiac Shunt.

    PubMed

    Granati, Glen T; Teressa, Getu

    2016-01-01

    BACKGROUND Patent foramen ovale (PFO) are common, normally resulting in a left-to-right shunt or no net shunting. Pulmonary embolism (PE) can cause sustained increased pulmonary vascular resistance (PVR) and right atrial pressure. Increasing positive end-expiratory pressure (PEEP) improves oxygenation at the expense of increasing intrathoracic pressures (ITP). Airway pressure release ventilation (APRV) decreases shunt fraction, improves ventilation/perfusion (V/Q) matching, increases cardiac output, and decreases right atrial pressure by facilitating low airway pressure. CASE REPORT A 40-year-old man presented with dyspnea and hemoptysis. Oxygen saturation (SaO2) 80% on room air with A-a gradient of 633 mmHg. Post-intubation SaO2 dropped to 71% on assist control, FiO2 100%, and PEEP of 5 cmH20. Successive PEEP dropped SaO2 to 60-70% and blood pressure plummeted. APRV was initaiated with improvement in SaO2 to 95% and improvement in blood pressure. Hemiparesis developed and CT head showed infarction. CT pulmonary angiogram found a large pulmonary embolism. Transthoracic echocardiogram detected right-to left intracardiac shunt, with large PFO. CONCLUSIONS There should be suspicion for a PFO when severe hypoxemia paradoxically worsens in response to increasing airway pressures. Concomitant venous and arterial thromboemboli should prompt evaluation for intra-cardiac shunt. Patients with PFO and hypoxemia should be evaluated for causes of sustained right-to-left pressure gradient, such as PE. Management should aim to decrease PVR and optimize V/Q matching by treating the inciting incident (e.g., thrombolytics in PE) and by minimizing ITP. APRV can minimize PVR and maximize V/Q ratios and should be considered in treating patients similar to the one whose case is presented here. PMID:27377010

  12. Advances in the continuous monitoring of erosion and deposition dynamics: Developments and applications of the new PEEP-3T system

    NASA Astrophysics Data System (ADS)

    Lawler, D. M.

    2008-01-01

    In most episodic erosion and deposition systems, knowledge of the timing of geomorphological change, in relation to fluctuations in the driving forces, is crucial to strong erosion process inference, and model building, validation and development. A challenge for geomorphology, however, is that few studies have focused on geomorphological event structure (timing, magnitude, frequency and duration of individual erosion and deposition events), in relation to applied stresses, because of the absence of key monitoring methodologies. This paper therefore (a) presents full details of a new erosion and deposition measurement system — PEEP-3T — developed from the Photo-Electronic Erosion Pin sensor in five key areas, including the addition of nocturnal monitoring through the integration of the Thermal Consonance Timing (TCT) concept, to produce a continuous sensing system; (b) presents novel high-resolution datasets from the redesigned PEEP-3T system for river bank system of the Rivers Nidd and Wharfe, northern England, UK; and (c) comments on their potential for wider application throughout geomorphology to address these key measurement challenges. Relative to manual methods of erosion and deposition quantification, continuous PEEP-3T methodologies increase the temporal resolution of erosion/deposition event detection by more than three orders of magnitude (better than 1-second resolution if required), and this facility can significantly enhance process inference. Results show that river banks are highly dynamic thermally and respond quickly to radiation inputs. Data on bank retreat timing, fixed with PEEP-3T TCT evidence, confirmed that they were significantly delayed up to 55 h after flood peaks. One event occurred 13 h after emergence from the flow. This suggests that mass failure processes rather than fluid entrainment dominated the system. It is also shown how, by integrating turbidity instrumentation with TCT ideas, linkages between sediment supply and sediment

  13. The Birth to School Study: Evidence on the Effectiveness of PEEP, an Early Intervention for Children at Risk of Educational Under-Achievement

    ERIC Educational Resources Information Center

    Evangelou, Maria; Brooks, Greg; Smith, Sally

    2007-01-01

    This article presents the findings of the Birth to School Study (BTSS) a longitudinal evaluation of the Peers Early Education Partnership (PEEP); a family-focused intervention aimed at promoting early literacy, numeracy and self-esteem in a community at risk of educational underachievement. The main aim of the study was to investigate the effects…

  14. Worsening Hypoxemia in the Face of Increasing PEEP: A Case of Large Pulmonary Embolism in the Setting of Intracardiac Shunt

    PubMed Central

    Granati, Glen T.; Teressa, Getu

    2016-01-01

    Patient: Male, 40 Final Diagnosis: Patent foramen ovale Symptoms: Dyspnea exertional • hemoptysis • shortness of breath Medication: — Clinical Procedure: Airway pressure release ventilation Specialty: Critical Care Medicine Objective: Rare co-existance of disease or pathology Background: Patent foramen ovale (PFO) are common, normally resulting in a left to right shunt or no net shunting. Pulmonary embolism (PE) can cause sustained increased pulmonary vascular resistance (PVR) and right atrial pressure. Increasing positive end-expiratory pressure (PEEP) improves oxygenation at the expense of increasing intrathoracic pressures (ITP). Airway pressure release ventilation (APRV) decreases shunt fraction, improves ventilation/perfusion (V/Q) matching, increases cardiac output, and decreases right atrial pressure by facilitating low airway pressure. Case Report: A 40-year-old man presented with dyspnea and hemoptysis. Oxygen saturation (SaO2) 80% on room air with A a gradient of 633 mmHg. Post-intubation SaO2 dropped to 71% on assist control, FiO2 100%, and PEEP of 5 cmH20. Successive PEEP dropped SaO2 to 60–70% and blood pressure plummeted. APRV was initaiated with improvement in SaO2 to 95% and improvement in blood pressure. Hemiparesis developed and CT head showed infarction. CT pulmonary angiogram found a large pulmonary embolism. Transthoracic echocardiogram detected right-to left intracardiac shunt, with large PFO. Conclusions: There should be suspicion for a PFO when severe hypoxemia paradoxically worsens in response to increasing airway pressures. Concomitant venous and arterial thromboemboli should prompt evaluation for intra cardiac shunt. Patients with PFO and hypoxemia should be evaluated for causes of sustained right-to left pressure gradient, such as PE. Management should aim to decrease PVR and optimize V/Q matching by treating the inciting incident (e.g., thrombolytics in PE) and by minimizing ITP. APRV can minimize PVR and maximize V/Q ratios and

  15. NOAA People Empowered Products (PeEP): Combining social media with scientific models to provide eye-witness confirmed products

    NASA Astrophysics Data System (ADS)

    Codrescu, S.; Green, J. C.; Redmon, R. J.; Denig, W. F.; Kihn, E. A.

    2012-12-01

    NOAA products and alerts rely on combinations of models and data to provide the public with information regarding space and terrestrial weather hazards. This operational paradigm, while effective, neglects an abundant free source of measurements: millions of eyewitnesses viewing weather events. Here we present a prototype product that combines user reports with scientific model output and discuss the possibilities for creating a generic PeEP framework for use in a wide range of applications. We demonstrate the capabilities of a proto-PeEP that combines the OVATION prime auroral model running at the NOAA National Geophysical Data Center with Twitter reports of observable aurora. The combined product displays the model aurora in real time on Google Earth with markers showing the location and text of tweets from people actually observing the aurora. We discuss how the application can be extended and incorporated to other space weather products such as ionospheric induced GPS errors and radiation related satellite anomalies.

  16. Monitoring of intratidal lung mechanics: a Graphical User Interface for a model-based decision support system for PEEP-titration in mechanical ventilation.

    PubMed

    Buehler, S; Lozano-Zahonero, S; Schumann, S; Guttmann, J

    2014-12-01

    In mechanical ventilation, a careful setting of the ventilation parameters in accordance with the current individual state of the lung is crucial to minimize ventilator induced lung injury. Positive end-expiratory pressure (PEEP) has to be set to prevent collapse of the alveoli, however at the same time overdistension should be avoided. Classic approaches of analyzing static respiratory system mechanics fail in particular if lung injury already prevails. A new approach of analyzing dynamic respiratory system mechanics to set PEEP uses the intratidal, volume-dependent compliance which is believed to stay relatively constant during one breath only if neither atelectasis nor overdistension occurs. To test the success of this dynamic approach systematically at bedside or in an animal study, automation of the computing steps is necessary. A decision support system for optimizing PEEP in form of a Graphical User Interface (GUI) was targeted. Respiratory system mechanics were analyzed using the gliding SLICE method. The resulting shapes of the intratidal compliance-volume curve were classified into one of six categories, each associated with a PEEP-suggestion. The GUI should include a graphical representation of the results as well as a quality check to judge the reliability of the suggestion. The implementation of a user-friendly GUI was successfully realized. The agreement between modelled and measured pressure data [expressed as root-mean-square (RMS)] tested during the implementation phase with real respiratory data from two patient studies was below 0.2 mbar for data taken in volume controlled mode and below 0.4 mbar for data taken in pressure controlled mode except for two cases with RMS < 0.6 mbar. Visual inspections showed, that good and medium quality data could be reliably identified. The new GUI allows visualization of intratidal compliance-volume curves on a breath-by-breath basis. The automatic categorisation of curve shape into one of six shape

  17. NOAA People Empowered Products (PeEP): Combining social media with scientific models to provide eye-witness confirmed products

    NASA Astrophysics Data System (ADS)

    Codrescu, S.; Green, J. C.; Redmon, R. J.; Minor, K.; Denig, W. F.; Kihn, E. A.

    2013-12-01

    NOAA products and alerts rely on combinations of models and data to provide the public with information regarding space and terrestrial weather phenomena and hazards. This operational paradigm, while effective, neglects an abundant free source of measurements: millions of eyewitnesses viewing weather events. We demonstrate the capabilities of a prototype People Empowered Product (PeEP) that combines the OVATION prime auroral model running at the NOAA National Geophysical Data Center with Twitter reports of observable aurora. We introduce an algorithm for scoring Tweets based on keywords to improve the signal to noise of this dynamic data source. We use the location of the aurora derived from this new database of crowd sourced observations to validate the OVATION model for use in auroral forecasting. The combined product displays the model aurora in real time with markers showing the location and text of tweets from people actually observing the aurora. We discuss how the application might be extended to other space weather products such as radiation related satellite anomalies.

  18. The effect of pre-existing pulmonary vascular disease on the response to mechanical ventilation with PEEP following open-heart surgery.

    PubMed

    Trichet, B; Falke, K; Togut, A; Laver, M B

    1975-01-01

    The effects of mechanical ventilation with and without positive end-expiratory pressure (PEEP) on hemodynamic performance and blood-gas exchange were studied in ten patients following open-heart surgery. Ventilation at constant tidal volume (15 ml/kg body weight) with 10 cm H2O PEEP following aortic valve replacement (AVR) IN FIVE PATIENTs without pulmonary vascular disease was associated with the following significant changes: a rise in arterial Po2, a fall in the alveolar-arterial Po2 gradient when Fio2 = 1.0, decreases in calculated Qs/Qt and cardiac index. Using a similar pattern of ventilation following mitral valve replacement (MVR) in patients with elevated pulmonary vascular resistance, we found a significant decrease in cardiac index (but less than in the AVR group), a significant elevation of calculated physiologic deadspace (Vd/Vt) and no change in Qs/Qt. An hour after removal of PEEP, intravascular pressures, blood flow and blood-gas exchange values of all patients with AVR had returned to control levels; patients with MVR had persistently significantly low cardiac indices, while Vd/Vt returned to pre-PEEP values. These findings suggest that evaluation of responses to different ventilation patterns must take into account pre-existing V/Q abnormalities secondary to pulmonary vascular disease, particularly when these are secondary to chronic congestive heart failure. Following AVR, Qs/Qt changed in the same direction as cardiac index (CI) irrespective of ventilatory pattern: CI decreased and rose as CI increased. The authors conclude that with increasing severity of pulmonary vascular disease, changes in airway pressure will have an unpredictable effect on cardiac index unless the level of myocardial competence is taken into account. In the presence of ventricular failure, changes in pleural (and therefore transmural) pressures will be minimal compared with the high filling pressures and exert no influence on stroke volume. Although pulmonary venous

  19. The Peep Show

    ERIC Educational Resources Information Center

    Gamble, David L.

    2010-01-01

    Three years ago, the author and Linda Arbuckle (University of Florida ceramic professor and internationally known majolica clay artist) were on the phone discussing how electric kilns just don't have any artistic design flair to them. The round kiln has basic properties that allow it to function properly, but its looks are far from exciting. They…

  20. Influence of posture and positive end-tidal expiratory pressure (PEEP) on clearance of Tc99m-DTPA from the lungs

    SciTech Connect

    Mason, G.R.; Maublant, J.; Sietsema, K.; Effros, R.M.; Mena, I.

    1984-01-01

    The clearance of Tc99m-DTPA aerosols from the lung has been used to detect and quantitate alterations in the permeability of the pulmonary epithelium. Clearance of the radionuclide is accelerated by both chronic and acute injuries to the lung and by smoking. Several laboratories have reported that Tc99m-DTPA clearance from upper lobes exceeded that from lower lobes in upright subjects. To investigate this phenomenon further the authors studied subjects with simultaneous anterior and posterior cameras in upright and supine positions. In the upright position, clearance from both the anterior and posterior upper regions of interest (ROI's) exceeded the lower regions (-1.64 +- .42 S.D. vs. -0.75 +- .41, anterior, p < .05, n=6), -1.04 +- .23 vs. -0.50 +- .36, posterior. All units = %/min. This difference was not observed in the supine subjects. Clearance from the anterior chest exceeded that from the posterior chest in the supine subjects (-1.28 +- .45 vs. -0.05 +- 1.08) and a small increase in radio-activity was observed in at least one ROI of 5 of 6 subjects from the posterior camera. An increase in activity is likely to be secondary to labeling of blood pool, which would have greatest affect where pulmonary blood volume is largest. Computer processing of the entire lung without observer bias in ROI placement showed similar effects of posture over non-peripheral ROI's. Five subjects breathed on PEEP to cause airspace distention, causing clearance to double. Both dependency and airspace distention appear to influence clearance of aerosolized DTPA, the latter may occur by stretching of epithelial pores.

  1. "Government of da Peeps, for da Peeps, and by da Peeps": Revisiting the Contact Zone

    ERIC Educational Resources Information Center

    Maxson, Jeffrey

    2005-01-01

    In this article, I review contact zone pedagogy from a perspective of discursive positioning and with attention to two assignments that ask basic writers to play with the conventions of academic language. The first requires them to translate a passage of academic prose into a slang of their choice; the second, to compose a parody of academic…

  2. Of gossips, eavesdroppers, and peeping toms

    PubMed Central

    Francis, Huw W S

    1982-01-01

    British accounts of medical ethics concentrate on confidentiality to the exclusion of wider questions of privacy. This paper argues for consideration of privacy within medical ethics, and illustrates through the television series `Hospital', what may go awry when this wider concept is forgotten. PMID:7131499

  3. Production of Energy Efficient Preform Structures (PEEPS)

    SciTech Connect

    Dr. John A. Baumann

    2012-06-08

    Due to its low density, good structural characteristics, excellent fabrication properties, and attractive appearance, aluminum metal and its alloys continue to be widely utilized. The transportation industry continues to be the largest consumer of aluminum products, with aerospace as the principal driver for this use. Boeing has long been the largest single company consumer of heat-treated aluminum in the U.S. The extensive use of aluminum to build aircraft and launch vehicles has been sustained, despite the growing reliance on more structurally efficient carbon fiber reinforced composite materials. The trend in the aerospace industry over the past several decades has been to rely extensively on large, complex, thin-walled, monolithic machined structural components, which are fabricated from heavy billets and thick plate using high speed machining. The use of these high buy-to-fly ratio starting product forms, while currently cost effective, is energy inefficient, with a high environmental impact. The widespread implementation of Solid State Joining (SSJ) technologies, to produce lower buy-to-fly ratio starting forms, tailored to each specific application, offers the potential for a more sustainable manufacturing strategy, which would consume less energy, require less material, and reduce material and manufacturing costs. One objective of this project was to project the energy benefits of using SSJ techniques to produce high-performance aluminum structures if implemented in the production of the world fleet of commercial aircraft. A further objective was to produce an energy consumption prediction model, capable of calculating the total energy consumption, solid waste burden, acidification potential, and CO2 burden in producing a starting product form - whether by conventional or SSJ processes - and machining that to a final part configuration. The model needed to be capable of computing and comparing, on an individual part/geometry basis, multiple possible manufacturing pathways, to identify the best balance of energy consumption and environmental impact. This model has been created and populated with energy consumption data for individual SSJ processes and process platforms. Technology feasibility cases studies were executed, to validate the model, and confirm the ability to create lower buy-to-fly ratio performs and machine these to final configuration aircraft components. This model can now be used as a tool to select manufacturing pathways that offer significant energy savings and, when coupled with a cost model, drive implementation of the SSJ processes.

  4. Plurilingual Ethos: A Peep into the Sociology of Language.

    ERIC Educational Resources Information Center

    Khubchandani, Lachman M.

    1998-01-01

    Issues in the study of bilingualism and multilingualism in India and Pakistan are examined, including the delineation of linguistic boundaries, defining a society that is multicultural and yet has developed a "communication ethos" based on a core of common experience, the difficulty in interpreting language role and defining language usage in a…

  5. Lunar Nitrogen Problem: A peep at individual mineral grains

    NASA Astrophysics Data System (ADS)

    Sripada, V. S. Murty; Mahajan, R. R.

    2012-07-01

    The lunar surface is continuously receiving solar wind (SW) implantation, due to lack of atmosphere and intrinsic magnetic field. As a result, grains at the surface are loaded with SW nitrogen and noble gases, making the lunar soils an excellent means to understand the composition of these elements in the SW. A surprise finding since the Apollo era has been the over abundance of nitrogen in lunar soils by about an order of magnitude than expected from noble gases [ ^{14}N/ ^{36}Ar ˜ 360, as against 37 for SW]. In addition, the nitrogen isotopic composition of lunar soil ranges from -240 to +100 per mil, while pure SW nitrogen is -400 per mil. The excess N in lunar soils and its isotopic range still elude an explanation and termed as the ``Lunar Nitrogen Problem''. As would be expected, similar behavior of N and noble gases has been observed in lunar meteorites also. A simultaneous study of N and noble gases is necessary to better address this problem and such studies are sparse in literature. Also, lunar soil consists of an ensemble of different mineral grains, each receiving SW during multiple surface exposures due to regolith gardening and also each grain has different retentivity for SW implanted species. Bulk soil analysis will provide an average picture of the ensemble of grains it has. To better characterize the nitrogen components, it is more appropriate to analyse individual grains. We have developed a laser heating system with low blanks, attached with a mass spectrometer that can analyse all noble gases and nitrogen (in pico mole amounts) for isotopic composition, to investigate this problem. We have analysed individual mineral grains (weighing few hundred micro grams) from the lunar meteorite Y983885 for noble gases and nitrogen. So far we have studied ilmenite grains (analysis of other mineral grains is in progress) by stepwise heating method in an effort to resolve the multiple nitrogen components. The release pattern of N, δ ^{15}N and ^{14}N/ ^{36}Ar of the grains is similar to the findings from the bulk sample of Y983885, though the absolute values of these quantities showed differences, reflecting the surface exposure history of individual grains. The low temperature releases in particular, wherein the most labile and recently added surface component resides shows a higher ^{14}N/ ^{36}Ar ratio with positive δ ^{15}N, consistent with bulk sample data. We use the data from grains with lower SW component to characterize the cosmogenic components and use this information for correcting the data to estimate the non-solar N component and identify its source.

  6. A peep beyond S.S.T.O. mass marginality

    NASA Astrophysics Data System (ADS)

    Vandenkerckhove, J. A.

    1992-08-01

    The use of combined ejector-ramjet-scramjet-rocket engines for the recoverable/reusable Single-Stage-To-Orbit (SSTO) satellite launcher is discussed. The performance of a 240-t SSTO vehicle is assessed for selected vehicle and trajectory assumptions. The results suggest that the development of an SSTO with fairly high performance (payload fraction in excess of 4-5 percent) may be feasible, provided that the scramjet-rocket transition can take place at about Mach 15. Such an SSTO is no longer mass critical.

  7. A Peep into the Uncertainty-Complexity-Relevance Modeling Trilemma through Global Sensitivity and Uncertainty Analysis

    NASA Astrophysics Data System (ADS)

    Munoz-Carpena, R.; Muller, S. J.; Chu, M.; Kiker, G. A.; Perz, S. G.

    2014-12-01

    Model Model complexity resulting from the need to integrate environmental system components cannot be understated. In particular, additional emphasis is urgently needed on rational approaches to guide decision making through uncertainties surrounding the integrated system across decision-relevant scales. However, in spite of the difficulties that the consideration of modeling uncertainty represent for the decision process, it should not be avoided or the value and science behind the models will be undermined. These two issues; i.e., the need for coupled models that can answer the pertinent questions and the need for models that do so with sufficient certainty, are the key indicators of a model's relevance. Model relevance is inextricably linked with model complexity. Although model complexity has advanced greatly in recent years there has been little work to rigorously characterize the threshold of relevance in integrated and complex models. Formally assessing the relevance of the model in the face of increasing complexity would be valuable because there is growing unease among developers and users of complex models about the cumulative effects of various sources of uncertainty on model outputs. In particular, this issue has prompted doubt over whether the considerable effort going into further elaborating complex models will in fact yield the expected payback. New approaches have been proposed recently to evaluate the uncertainty-complexity-relevance modeling trilemma (Muller, Muñoz-Carpena and Kiker, 2011) by incorporating state-of-the-art global sensitivity and uncertainty analysis (GSA/UA) in every step of the model development so as to quantify not only the uncertainty introduced by the addition of new environmental components, but the effect that these new components have over existing components (interactions, non-linear responses). Outputs from the analysis can also be used to quantify system resilience (stability, alternative states, thresholds or tipping points) in the face of environmental and anthropogenic change (Perz, Muñoz-Carpena, Kiker and Holt, 2013), and through MonteCarlo mapping potential management activities over the most important factors or processes to influence the system towards behavioral (desirable) outcomes (Chu-Agor, Muñoz-Carpena et al., 2012).

  8. From the Secondary Section: Mentoring New Teachers by Empowering the "Peeps"

    ERIC Educational Resources Information Center

    Haas, Kay Parks

    2012-01-01

    If the author was to pinpoint her greatest passion as an educator, it would be that of mentoring teachers. Everyone knows the statistics of how many new teachers leave the profession after just a few years and that one of the factors in retaining them lies in the value of a quality mentor. Looking back, the author realizes that educators' first…

  9. Peeping at TOMs-Diverse Entry Gates to Mitochondria Provide Insights into the Evolution of Eukaryotes.

    PubMed

    Mani, Jan; Meisinger, Chris; Schneider, André

    2016-02-01

    Mitochondria are essential for eukaryotic life and more than 95% of their proteins are imported as precursors from the cytosol. The targeting signals for this posttranslational import are conserved in all eukaryotes. However, this conservation does not hold true for the protein translocase of the mitochondrial outer membrane that serves as entry gate for essentially all precursor proteins. Only two of its subunits, Tom40 and Tom22, are conserved and thus likely were present in the last eukaryotic common ancestor. Tom7 is found in representatives of all supergroups except the Excavates. This suggests that it was added to the core of the translocase after the Excavates segregated from all other eukaryotes. A comparative analysis of the biochemically and functionally characterized outer membrane translocases of yeast, plants, and trypanosomes, which represent three eukaryotic supergroups, shows that the receptors that recognize the conserved import signals differ strongly between the different systems. They present a remarkable example of convergent evolution at the molecular level. The structural diversity of the functionally conserved import receptors therefore provides insight into the early evolutionary history of mitochondria. PMID:26474847

  10. Prehospital Evaluation of Effusion, Pneumothorax, and Standstill (PEEPS): Point-of-care Ultrasound in Emergency Medical Services

    PubMed Central

    Bhat, Sundeep R.; Johnson, David A.; Pierog, Jessica E.; Zaia, Brita E.; Williams, Sarah R.; Gharahbaghian, Laleh

    2015-01-01

    Introduction In the United States, there are limited studies regarding use of prehospital ultrasound (US) by emergency medical service (EMS) providers. Field diagnosis of life-threatening conditions using US could be of great utility. This study assesses the ability of EMS providers and students to accurately interpret heart and lung US images. Methods We tested certified emergency medical technicians (EMT-B) and paramedics (EMT-P) as well as EMT-B and EMT-P students enrolled in prehospital training programs within two California counties. Participants completed a pre-test of sonographic imaging of normal findings and three pathologic findings: pericardial effusion, pneumothorax, and cardiac standstill. A focused one-hour lecture on emergency US imaging followed. Post-tests were given to all EMS providers immediately following the lecture and to a subgroup one week later. Results We enrolled 57 prehospital providers (19 EMT-B students, 16 EMT-P students, 18 certified EMT-B, and 4 certified EMT-P). The mean pre-test score was 65.2%±12.7% with mean immediate post-test score of 91.1%±7.9% (95% CI [22%–30%], p<0.001). Scores significantly improved for all three pathologic findings. Nineteen subjects took the one-week post-test. Their mean score remained significantly higher: pre-test 65.8%±10.7%; immediate post-test 90.5%±7.0% (95% CI [19%–31%], p<0.001), one-week post-test 93.1%±8.3% (95% CI [21%–34%], p<0.001). Conclusion Using a small sample of EMS providers and students, this study shows the potential feasibility for educating prehospital providers to accurately identify images of pericardial effusion, pneumothorax, and cardiac standstill after a focused lecture. PMID:26265961

  11. Peeping into genomic architecture by re-sequencing of Ochrobactrum intermedium M86 strain during laboratory adapted conditions.

    PubMed

    Gohil, Kushal N; Neurgaonkar, Priya S; Paranjpe, Aditi; Dastager, Syed G; Dharne, Mahesh S

    2016-06-01

    Advances in de novo sequencing technologies allow us to track deeper insights into microbial genomes for restructuring events during the course of their evolution inside and outside the host. Bacterial species belonging to Ochrobactrum genus are being reported as emerging, and opportunistic pathogens in this technology driven era probably due to insertion and deletion of genes. The Ochrobactrum intermedium M86 was isolated in 2005 from a case of non-ulcer dyspeptic human stomach followed by its first draft genome sequence in 2009. Here we report re-sequencing of O. intermedium M86 laboratory adapted strain in terms of gain and loss of genes. We also attempted for finer scale genome sequence with 10 times more genome coverage than earlier one followed by comparative evaluation on Ion PGM and Illumina MiSeq. Despite their similarities at genomic level, lab-adapted strain mainly lacked genes encoding for transposase protein, insertion elements family, phage tail-proteins that were not detected in original strain on both chromosomes. Interestingly, a 5 kb indel was detected in chromosome 2 that was absent in original strain mapped with phage integrase gene of Rhizobium spp. and may be acquired and integrated through horizontal gene transfer indicating the gene loss and gene gain phenomenon in this genus. Majority of indel fragments did not match with known genes indicating more bioinformatic dissection of this fragment. Additionally we report genes related to antibiotic resistance, heavy metal tolerance in earlier and re-sequenced strain. Though SNPs detected, there did not span urease and flagellar genes. We also conclude that third generation sequencing technologies might be useful for understanding genomic architecture and re-arrangement of genes in the genome due to their ability of larger coverage that can be used to trace evolutionary aspects in microbial system. PMID:27222803

  12. The Application of High-Resolution Electron Microscopy to Problems in Solid State Chemistry: The Exploits of a Peeping TEM.

    ERIC Educational Resources Information Center

    Eyring, LeRoy

    1980-01-01

    Describes methods for using the high-resolution electron microscope in conjunction with other tools to reveal the identity and environment of atoms. Problems discussed include the ultimate structure of real crystalline solids including defect structure and the mechanisms of chemical reactions. (CS)

  13. Foreign Language and Cross-Cultural Education in the Promotion of International Trade: PEEP, A Case Study.

    ERIC Educational Resources Information Center

    Peniche, Eduardo A.

    1985-01-01

    Discusses the Piedmont Export Expansion Program that was formed to establish a cooperative program between businesses engaged in foreign commerce and regional institutions of higher education. The purpose is to further develop, through a series of seminars, workshops, and regular academic instruction, international trade for the Piedmont area of…

  14. Act on Gender: A Peep into Intra-Household Water Use in the Australian Capital Territory (ACT) Region

    ERIC Educational Resources Information Center

    Lahiri-Dutt, Kuntala; Harriden, Kate

    2008-01-01

    Intra-household water use and management from a gender perspective has remained a relatively under-researched theme in developed countries. Australia is no exception, with the lack of research particularly evident in the many rural and peri-urban communities. These communities have experienced significant water scarcity in recent years. In this…

  15. A Project to Evaluate the Effectiveness of Pre-Phonic Training Between Kindergarten and First Grade Levels (Project PEEP). Final Report.

    ERIC Educational Resources Information Center

    Marko, Kathleen Barrett

    The effectiveness of prephonic training between kindergarten and first grade levels as a tool for acquiring reading skills was explored throughout the public school system in the city of New Bedford, Massachusetts. A sample population of 260 kindergartners was identified as having potential learning difficulties by the results shown on the…

  16. The biological effects of higher and lower positive end-expiratory pressure in pulmonary and extrapulmonary acute lung injury with intra-abdominal hypertension

    PubMed Central

    2014-01-01

    Introduction Mechanical ventilation with high positive end-expiratory pressure (PEEP) has been used in patients with acute respiratory distress syndrome (ARDS) and intra-abdominal hypertension (IAH), but the role of PEEP in minimizing lung injury remains controversial. We hypothesized that in the presence of acute lung injury (ALI) with IAH: 1) higher PEEP levels improve pulmonary morphofunction and minimize lung injury; and 2) the biological effects of higher PEEP are more effective in extrapulmonary (exp) than pulmonary (p) ALI. Methods In 48 adult male Wistar rats, ALIp and ALIexp were induced by Escherichia coli lipopolysaccharide intratracheally and intraperitoneally, respectively. After 24 hours, animals were anesthetized and mechanically ventilated (tidal volume of 6 mL/kg). IAH (15 mmHg) was induced and rats randomly assigned to PEEP of 5 (PEEP5), 7 (PEEP7) or 10 (PEEP10) cmH2O for 1 hour. Results In both ALIp and ALIexp, higher PEEP levels improved oxygenation. PEEP10 increased alveolar hyperinflation and epithelial cell damage compared to PEEP5, independent of ALI etiology. In ALIp, PEEP7 and PEEP10 increased lung elastance compared to PEEP5 (4.3 ± 0.7 and 4.3 ± 0.9 versus 3.1 ± 0.3 cmH2O/mL, respectively, P <0.01), without changes in alveolar collapse, interleukin-6, caspase-3, type III procollagen, receptor for advanced glycation end-products, and vascular cell adhesion molecule-1 expressions. Moreover, PEEP10 increased diaphragmatic injury compared to PEEP5. In ALIexp, PEEP7 decreased lung elastance and alveolar collapse compared to PEEP5 (2.3 ± 0.5 versus 3.6 ± 0.7 cmH2O/mL, P <0.02, and 27.2 (24.7 to 36.8) versus 44.2 (39.7 to 56.9)%, P <0.05, respectively), while PEEP7 and PEEP10 increased interleukin-6 and type III procollagen expressions, as well as type II epithelial cell damage compared to PEEP5. Conclusions In the current models of ALI with IAH, in contrast to our primary hypothesis, higher PEEP is more effective in

  17. High or conventional positive end-expiratory pressure in adult respiratory distress syndrome.

    PubMed

    Díaz-Alersi, R; Navarro-Ramírez, C

    2014-01-01

    Patients with acute respiratory distress syndrome may require high positive end-expiratory pressure (PEEP) levels, though the optimum level remains to be established. Several clinical trials have compared high PEEP levels versus conventional PEEP. Overall, although high PEEP levels improve oxygenation and are safe, they do not result in a significant reduction of the mortality rates. Nevertheless, some metaanalyses have revealed 2 situations in which high PEEP may decrease mortality: When used in severe distress and when PEEP is set following the characteristics of lung mechanics. Five studies have explored this latter scenario. Unfortunately, all of them have small sample sizes and have used different means to determine optimum PEEP. It is therefore necessary to conduct studies of sufficient sample size to compare the treatment of patients with severe acute respiratory distress syndrome, using a protective ventilation strategy with high PEEP guided by the characteristics of lung mechanics and ventilation with the protocol proposed by the ARDS Network. PMID:24290732

  18. The MyPEEPS randomized controlled trial: A pilot of preliminary efficacy, feasibility, and acceptability of a group-level, HIV risk reduction intervention for young men who have sex with men

    PubMed Central

    Hidalgo, Marco A.; Kuhns, Lisa M.; Hotton, Anna L.; Johnson, Amy K.; Mustanski, Brian; Garofalo, Robert

    2015-01-01

    An exigent need exists for HIV prevention intervention research targeting young men who have sex with men (MSM) – a group of young adults that, despite composing the highest and most racially disproportionate rates of HIV incidence, has been least often the focus of behavioral intervention research. This pilot study tested a group-based HIV primary prevention intervention for young MSM to evaluate its initial efficacy, feasibility, and acceptability. Participants were randomized (N=101; aged 16-20 years) to one of two group-level, HIV and STI education programs: controls participated in a non-interactive, lecture-based program while intervention participants took part in a highly interactive program tailored to young MSM aged 16-20. Sexual risk and social cognitive outcomes were assessed at baseline, and 6- and 12 weeks post-intervention. Over the entire follow-up period, intervention participants were less likely than controls to engage in any sexual behavior while under the influence of substances (p<0.05), and also observed in this group was a decreasing trend of unprotected anal sex while under the influence of substances (p=.08). Follow-up differences between groups on social cognitive outcomes favored the intervention group, though these differences were non-significant. Acceptability ratings were modest. A 6-session behavioral intervention tailored to young MSM, aged 16-20, is feasible, acceptable, and demonstrates evidence of preliminary efficacy in reducing sexual risk, specifically sexual risk while under the influence of substances. PMID:25135064

  19. Positive end-expiratory pressure preserves surfactant function in preterm lambs.

    PubMed

    Michna, J; Jobe, A H; Ikegami, M

    1999-08-01

    Ventilation style influences lung injury and the amount of large-aggregate biophysically active surfactant in adult lungs. We asked how positive end-expiratory pressures (PEEP) would influence clinical responses and surfactant pools in surfactant-treated preterm lambs ventilated for 7 h with tidal volumes (VT) of 10 ml/kg. The 126-d gestation preterms were delivered and treated with 100 mg/kg recombinant human surfactant protein C (rSP-C) containing surfactant and ventilated with zero, 4, or 7 cm H(2)O of PEEP. A comparison group was treated with natural sheep surfactant and ventilated with zero PEEP. Physiologic measurements were similar for lambs treated with rSP-C surfactant and natural surfactant. PEEP 4 and 7 improved oxygenation and compliance relative to either group of lambs ventilated with PEEP zero. The maximal lung volumes measured at 40 cm H(2)O pressure after 7 h ventilation for the PEEP 4 and 7 groups were more than double those measured for either PEEP zero group. Alveolar surfactant pools were larger for the PEEP 7 group, and the large-aggregate fraction was increased for the PEEP 4 and 7 groups, resulting in large-aggregate pool sizes that were 3-fold higher for the PEEP 4 and 4-fold higher for the PEEP 7 groups relative to the PEEP zero group treated with rSP-C surfactant. All large-aggregate surfactants lowered minimal surface tensions of a captive bubble to less than 5 mN/m. In preterm surfactant-treated lambs PEEP improved lung function and maintained more of an rSP-C surfactant in the biophysically active form. PMID:10430740

  20. Accuracy and precision of end-expiratory lung-volume measurements by automated nitrogen washout/washin technique in patients with acute respiratory distress syndrome

    PubMed Central

    2011-01-01

    Introduction End-expiratory lung volume (EELV) is decreased in acute respiratory distress syndrome (ARDS), and bedside EELV measurement may help to set positive end-expiratory pressure (PEEP). Nitrogen washout/washin for EELV measurement is available at the bedside, but assessments of accuracy and precision in real-life conditions are scant. Our purpose was to (a) assess EELV measurement precision in ARDS patients at two PEEP levels (three pairs of measurements), and (b) compare the changes (Δ) induced by PEEP for total EELV with the PEEP-induced changes in lung volume above functional residual capacity measured with passive spirometry (ΔPEEP-volume). The minimal predicted increase in lung volume was calculated from compliance at low PEEP and ΔPEEP to ensure the validity of lung-volume changes. Methods Thirty-four patients with ARDS were prospectively included in five university-hospital intensive care units. ΔEELV and ΔPEEP volumes were compared between 6 and 15 cm H2O of PEEP. Results After exclusion of three patients, variability of the nitrogen technique was less than 4%, and the largest difference between measurements was 81 ± 64 ml. ΔEELV and ΔPEEP-volume were only weakly correlated (r2 = 0.47); 95% confidence interval limits, -414 to 608 ml). In four patients with the highest PEEP (≥ 16 cm H2O), ΔEELV was lower than the minimal predicted increase in lung volume, suggesting flawed measurements, possibly due to leaks. Excluding those from the analysis markedly strengthened the correlation between ΔEELV and ΔPEEP volume (r2 = 0.80). Conclusions In most patients, the EELV technique has good reproducibility and accuracy, even at high PEEP. At high pressures, its accuracy may be limited in case of leaks. The minimal predicted increase in lung volume may help to check for accuracy. PMID:22166727

  1. Effects of ventilation with different positive end-expiratory pressures on cytokine expression in the preterm lamb lung.

    PubMed

    Naik, A S; Kallapur, S G; Bachurski, C J; Jobe, A H; Michna, J; Kramer, B W; Ikegami, M

    2001-08-01

    Ventilator-induced lung injury increases proinflammatory cytokines in the adult lung. We asked if positive end-expiratory pressure (PEEP) affects proinflammatory cytokine mRNA expression in the preterm lung. Preterm lambs at 129 +/- 3 d gestation were treated with 100 mg/kg recombinant human surfactant protein-C surfactant and ventilated for 2 or 7 h with 0, 4, or 7 cm H(2)O of PEEP. Unventilated fetal lambs were used as controls. Within 2 h of ventilation, alveolar total protein and activated neutrophils were increased and expression of mRNAs for the proinflammatory cytokines interleukin (IL)-1beta, IL-6, IL-8, and tumor necrosis factor-alpha (TNF-alpha) was increased in lung tissue of all ventilated animals relative to unventilated controls. Alveolar protein and neutrophils were higher for 0 and 7 PEEP animals than 4 PEEP animals. IL-1beta, IL-6, and IL-8 mRNAs were significantly elevated in animals ventilated with 0 PEEP compared with 4 PEEP. The percentage fractional area of collapsed alveoli was significantly higher for 0 PEEP compared with 4 and 7 PEEP groups. Mechanical ventilation increased the expression of proinflammatory mediators in surfactant-treated preterm lungs and the use of 4 PEEP minimized this response. PMID:11500356

  2. Paradoxical responses to positive end-expiratory pressure in patients with airway obstruction during controlled ventilation*

    PubMed Central

    Caramez, Maria Paula; Borges, Joao B.; Tucci, Mauro R.; Okamoto, Valdelis N.; Carvalho, Carlos R. R.; Kacmarek, Robert M.; Malhotra, Atul; Velasco, Irineu Tadeu; Amato, Marcelo B. P.

    2008-01-01

    Objective To reevaluate the clinical impact of external positive end-expiratory pressure (external-PEEP) application in patients with severe airway obstruction during controlled mechanical ventilation. The controversial occurrence of a paradoxic lung deflation promoted by PEEP was scrutinized. Design External-PEEP was applied stepwise (2 cm H2O, 5-min steps) from zero-PEEP to 150% of intrinsic-PEEP in patients already submitted to ventilatory settings minimizing overinflation. Two commonly used frequencies during permissive hypercapnia (6 and 9/min), combined with two different tidal volumes (VT: 6 and 9 mL/kg), were tested. Setting A hospital intensive care unit. Patients Eight patients were enrolled after confirmation of an obstructive lung disease (inspiratory resistance, >20 cm H2O/L per sec) and the presence of intrinsic-PEEP (≥5 cm H2O) despite the use of very low minute ventilation. Interventions All patients were continuously monitored for intra-arterial blood gas values, cardiac output, lung mechanics, and lung volume with plethysmography. Measurements and Main Results Three different responses to external-PEEP were observed, which were independent of ventilatory settings. In the biphasic response, isovolume-expiratory flows and lung volumes remained constant during progressive PEEP steps until a threshold, beyond which overinflation ensued. In the classic overinflation response, any increment of external-PEEP caused a decrease in isovolume-expiratory flows, with evident overinflation. In the paradoxic response, a drop in functional residual capacity during external-PEEP application (when compared to zero-external-PEEP) was commonly accompanied by decreased plateau pressures and total-PEEP, with increased isovolume-expiratory flows. The paradoxic response was observed in five of the eight patients (three with asthma and two with chronic obstructive pulmonary disease) during at least one ventilator pattern. Conclusions External-PEEP application may

  3. [Effect of using several levels of positive end-expiratory pressure over barotrauma's induced lung injury in a model of isolated and perfused rabbit lungs].

    PubMed

    Trejo, Humberto; Urich, Daniela; Pezzulo, Alejandro; Novoa, Eva; Marcano, Héctor; Crespo, Astrid; Sánchez de León, Roberto

    2006-03-01

    The use of Positive end-expiratory pressure (PEEP) as a strategy of mechanical ventilation offers its advantages, such as improved oxygenation, without causing alveolar overstretching and barotrauma. We aim to investigate the effect of several levels of PEEP on barotrauma and, whether an optimal level of PEEP exists. Forty-eight New Zealand rabbits (2.5-3.5 kg) were divided into four groups with PEEP settings of 0, 4, 8 and 12 cmH2O, at increasing levels of inspiratory volume (IV). This was done in blood perfused rabbit lungs and in lungs perfused with a Buffer-Albumin Solution. We observed that lungs ventilated with PEEP 0 cmH2O suffered pulmonary rupture at high IV (300cc), with significant increases of Pap (Pulmonary artery pressure) and FFR (Fluid filtration rate). Lungs ventilated with PEEP 8 and 12 suffered pulmonary rupture at lower IV (200cc and 150cc vs. 300cc respectively) On the other hand, lungs ventilated with PEEP 4 cmH2O reached the highest IV (400cc), in addition, they showed the lowest elevations of Pap and FFR. The acellular lungs ventilated with PEEP 4, 8 and 12 showed pulmonary rupture at lower IV when compared with cellular ones (300cc vs. 400cc: 100cc vs. 200cc and 100cc vs. 150cc respectively). We concluded that an optimal PEEP exists, which protects against barotrauma, however, excess of PEEP could enhance its development. The blood could contain some mediators which attenuate the damage induced by barotrauma. PMID:16562644

  4. Relationship of end-expiratory pressure, lung volume, and /sup 99m/Tc-DTPA clearance

    SciTech Connect

    Cooper, J.A.; van der Zee, H.; Line, B.R.; Malik, A.B.

    1987-10-01

    We investigated the dose-response effect of positive end-expiratory pressure (PEEP) and increased lung volume on the pulmonary clearance rate of aerosolized technetium-99m-labeled diethylenetriaminepentaacetic acid (99mTc-DTPA). Clearance of lung radioactivity was expressed as percent decrease per minute. Base-line clearance was measured while anesthetized sheep (n = 20) were ventilated with 0 cmH/sub 2/O end-expiratory pressure. Clearance was remeasured during ventilation at 2.5, 5, 10, 15, or 20 cmH/sub 2/O PEEP. Further studies showed stepwise increases in functional residual capacity (FRC) (P less than 0.05) measured at 0, 2.5, 5, 10, 15, and 20 cmH/sub 2/O PEEP. At 2.5 cmH/sub 2/O PEEP, the clearance rate was not different from that at base line (P less than 0.05), although FRC was increased from base line. Clearance rate increased progressively with increasing PEEP at 5, 10, and 15 cmH/sub 2/O (P less than 0.05). Between 15 and 20 cmH/sub 2/O PEEP, clearance rate was again unchanged, despite an increase in FRC. The pulmonary clearance of aerosolized /sup 99m/Tc-DTPA shows a sigmoidal response to increasing FRC and PEEP, having both threshold and maximal effects. This relationship is most consistent with the hypothesis that alveolar epithelial permeability is increased by lung inflation.

  5. Compliance is nonlinear over tidal volume irrespective of positive end-expiratory pressure level in surfactant-depleted piglets.

    PubMed

    Lichtwarck-Aschoff, M; Mols, G; Hedlund, A J; Kessler, V; Markström, A M; Guttmann, J; Hedenstierna, G; Sjöstrand, U H

    2000-12-01

    Between the lower and the upper inflection point of a quasistatic pressure-volume (PV) curve, a segment usually appears in which the PV relationship is steep and linear (i.e., compliance is high, with maximal volume change per pressure change, and is constant). Traditionally it is assumed that when positive end-expiratory pressure (PEEP) and tidal volume (V T) are titrated such that the end-inspiratory volume is positioned at this linear segment of the PV curve, compliance is constant over VT during ongoing ventilation. The validity of this assumption was addressed in this study. In 14 surfactant-deficient piglets, PEEP was increased from 3 cm H(2)O to 24 cm H(2)O, and the compliance associated with 10 consecutive volume increments up to full VT was determined with a modified multiple-occlusion method at the different PEEP levels. With PEEP at approximately the lower inflection point, compliance was minimal in most lungs and decreased markedly over VT, indicating overdistension. Compliance both increased and decreased within the same breath at intermediate PEEP levels. It is concluded that a PEEP that results in constant compliance over the full VT range is difficult to find, and cannot be derived from conventional respiratory-mechanical analyses; nor does this PEEP level coincide with maximal gas exchange. PMID:11112126

  6. Intraoperative ventilation strategies to prevent postoperative pulmonary complications: Systematic review, meta-analysis, and trial sequential analysis.

    PubMed

    Serpa Neto, Ary; Schultz, Marcus J; Gama de Abreu, Marcelo

    2015-09-01

    For many years, mechanical ventilation with high tidal volumes (V(T)) was common practice in operating theaters because this strategy recruits collapsed lung tissue, improves ventilation-perfusion mismatch, and thus decreases the need for high oxygen fractions. Positive end-expiratory pressure (PEEP) was seldom used because it could cause cardiac compromise. Increasing advances in the understanding of the mechanisms of ventilator-induced lung injury from animal studies and randomized controlled trials in patients with uninjured lungs in intensive care unit and operation room have pushed anesthesiologists to consider lung-protective strategies during intraoperative ventilation. These strategies at least include the use of low V(T), and perhaps also the use of PEEP, which when compared to high V(T) with low PEEP may prevent the occurrence of postoperative pulmonary complications (PPCs). Such protective effects, however, are likely ascribed to low V(T) rather than to PEEP. In fact, at least in nonobese patients undergoing open abdominal surgery, high PEEP does not protect against PPCs, and it can impair the hemodynamics. Further studies shall determine whether a strategy consisting of low V(T) combined with PEEP and recruitment maneuvers reduces PPCs in obese patients and other types of surgery (e.g., laparoscopic and thoracic), compared to low V(T) with low PEEP. Furthermore, the role of driving pressure for titrating ventilation settings in patients with uninjured lungs shall be investigated. PMID:26643098

  7. Airway distension promotes leukocyte recruitment in rat tracheal circulation.

    PubMed

    Lim, Lina H K; Wagner, Elizabeth M

    2003-11-01

    Mechanical distortion of blood vessels is known to activate endothelial cells. Whether airway distension likewise activates the vascular endothelium within the airway wall is unknown. Using intravital microscopy in the rat trachea, we investigated if airway distention with the application of positive end-expiratory pressure (PEEP) caused leukocyte recruitment to the airway. Tracheal postcapillary venules were visualized and leukocyte kinetics monitored in anesthetized, mechanically ventilated rats (80 breaths/minute, 6 ml/kg VT, 1 cm H(2)O PEEP). Leukocyte rolling velocity (Vwbc) and the number of adherent cells were not altered with normal ventilation over the course of 2 hours. Ventilation with sustained PEEP (8 cm H(2)O for 1 hour reduced Vwbc and increased adhesion, reaching a maximum at 1 hour of PEEP. Intermittent (2x and 5x) 8 cm H(2)O PEEP also induced a similar reduction in Vwbc, accompanied by an increase in adhesion. However, leukocyte recruitment after airway distension is localized to the airways because increased PEEP did not induce leukocyte recruitment in the mesenteric microcirculation or when PEEP was applied to the lung distal to the site of measurement. Pretreatment with endothelin receptor and selectin inhibitors blocked the effects of distension on leukocyte recruitment, suggesting their involvement in the proinflammatory response. PMID:12869357

  8. Positive End-Expiratory Pressure and Variable Ventilation in Lung-Healthy Rats under General Anesthesia

    PubMed Central

    Camilo, Luciana M.; Ávila, Mariana B.; Cruz, Luis Felipe S.; Ribeiro, Gabriel C. M.; Spieth, Peter M.; Reske, Andreas A.; Amato, Marcelo; Giannella-Neto, Antonio; Zin, Walter A.; Carvalho, Alysson R.

    2014-01-01

    Objectives Variable ventilation (VV) seems to improve respiratory function in acute lung injury and may be combined with positive end-expiratory pressure (PEEP) in order to protect the lungs even in healthy subjects. We hypothesized that VV in combination with moderate levels of PEEP reduce the deterioration of pulmonary function related to general anesthesia. Hence, we aimed at evaluating the alveolar stability and lung protection of the combination of VV at different PEEP levels. Design Randomized experimental study. Setting Animal research facility. Subjects Forty-nine male Wistar rats (200–270 g). Interventions Animals were ventilated during 2 hours with protective low tidal volume (VT) in volume control ventilation (VCV) or VV and PEEP adjusted at the level of minimum respiratory system elastance (Ers), obtained during a decremental PEEP trial subsequent to a recruitment maneuver, and 2 cmH2O above or below of this level. Measurements and Main Results Ers, gas exchange and hemodynamic variables were measured. Cytokines were determined in lung homogenate and plasma samples and left lung was used for histologic analysis and diffuse alveolar damage scoring. A progressive time-dependent increase in Ers was observed independent on ventilatory mode or PEEP level. Despite of that, the rate of increase of Ers and lung tissue IL-1 beta concentration were significantly lower in VV than in VCV at the level of the PEEP of minimum Ers. A significant increase in lung tissue cytokines (IL-6, IL-1 beta, CINC-1 and TNF-alpha) as well as a ventral to dorsal and cranial to caudal reduction in aeration was observed in all ventilated rats with no significant differences among groups. Conclusions VV combined with PEEP adjusted at the level of the PEEP of minimal Ers seemed to better prevent anesthesia-induced atelectasis and might improve lung protection throughout general anesthesia. PMID:25383882

  9. How to assess positive end-expiratory pressure-induced alveolar recruitment?

    PubMed

    Lu, Q

    2013-01-01

    Randomized trials fail to demonstrate a decrease in mortality when high Positive End-Expiratory Pressure (PEEP) is applied to patients with acute respiratory distress syndrome. Use of PEEP in all patients without taking into consideration specific lung morphology, potential for recruitment and risk of lung hyperinflation could be one of explanations. Assessment of alveolar recruitment in each individual patient appears to reach a good compromise between optimization of mechanical ventilation and reduction of lung injury due to systematic application of high PEEP. The purpose of the review was to discuss different methods to measure alveolar recruitment aimed at selecting optimal PEEP. The revision of the literature includes relevant human and animal studies published in the past ten years describing validated and promising methods. Computed tomography remains the reference method to assess regional PEEP-induced alveolar recruitment and hyperinflation. Lung ultrasound and pressure-volume (P-V) curve method are simple and repeatable at the bedside, but they can't provide information on lung hyperinflation. Electrical impedance tomography allows bedside assessment of tidal recruitment in dependent and nondependent regions. By measuring functional residual capacity, alveolar recruitment and strain can be estimated. Decremental PEEP titration preceded by recruitment maneuver has been suggested to define optimal PEEP that sustains oxygenation benefit of recruitment maneuver. Different methods are available to assess PEEP-induced alveolar recruitment. Lung ultrasound and P-V curve method can be easily used at bedside to assess lung recruitability and test optimal PEEP. Further development is required for bedside assessment combing alveolar recruitment with hyperinflation. PMID:23135694

  10. Cardiac output estimation using pulmonary mechanics in mechanically ventilated patients

    PubMed Central

    2010-01-01

    The application of positive end expiratory pressure (PEEP) in mechanically ventilated (MV) patients with acute respiratory distress syndrome (ARDS) decreases cardiac output (CO). Accurate measurement of CO is highly invasive and is not ideal for all MV critically ill patients. However, the link between the PEEP used in MV, and CO provides an opportunity to assess CO via MV therapy and other existing measurements, creating a CO measure without further invasiveness. This paper examines combining models of diffusion resistance and lung mechanics, to help predict CO changes due to PEEP. The CO estimator uses an initial measurement of pulmonary shunt, and estimations of shunt changes due to PEEP to predict CO at different levels of PEEP. Inputs to the cardiac model are the PV loops from the ventilator, as well as the oxygen saturation values using known respiratory inspired oxygen content. The outputs are estimates of pulmonary shunt and CO changes due to changes in applied PEEP. Data from two published studies are used to assess and initially validate this model. The model shows the effect on oxygenation due to decreased CO and decreased shunt, resulting from increased PEEP. It concludes that there is a trade off on oxygenation parameters. More clinically importantly, the model also examines how the rate of CO drop with increased PEEP can be used as a method to determine optimal PEEP, which may be used to optimise MV therapy with respect to the gas exchange achieved, as well as accounting for the impact on the cardiovascular system and its management. PMID:21108836

  11. Cardiac output estimation using pulmonary mechanics in mechanically ventilated patients.

    PubMed

    Sundaresan, Ashwath; Chase, J Geoffrey; Hann, Christopher E; Shaw, Geoffrey M

    2010-01-01

    The application of positive end expiratory pressure (PEEP) in mechanically ventilated (MV) patients with acute respiratory distress syndrome (ARDS) decreases cardiac output (CO). Accurate measurement of CO is highly invasive and is not ideal for all MV critically ill patients. However, the link between the PEEP used in MV, and CO provides an opportunity to assess CO via MV therapy and other existing measurements, creating a CO measure without further invasiveness.This paper examines combining models of diffusion resistance and lung mechanics, to help predict CO changes due to PEEP. The CO estimator uses an initial measurement of pulmonary shunt, and estimations of shunt changes due to PEEP to predict CO at different levels of PEEP. Inputs to the cardiac model are the PV loops from the ventilator, as well as the oxygen saturation values using known respiratory inspired oxygen content. The outputs are estimates of pulmonary shunt and CO changes due to changes in applied PEEP. Data from two published studies are used to assess and initially validate this model.The model shows the effect on oxygenation due to decreased CO and decreased shunt, resulting from increased PEEP. It concludes that there is a trade off on oxygenation parameters. More clinically importantly, the model also examines how the rate of CO drop with increased PEEP can be used as a method to determine optimal PEEP, which may be used to optimise MV therapy with respect to the gas exchange achieved, as well as accounting for the impact on the cardiovascular system and its management. PMID:21108836

  12. Lung ventilation strategies for acute respiratory distress syndrome: a systematic review and network meta-analysis.

    PubMed

    Wang, Changsong; Wang, Xiaoyang; Chi, Chunjie; Guo, Libo; Guo, Lei; Zhao, Nana; Wang, Weiwei; Pi, Xin; Sun, Bo; Lian, Ailing; Shi, Jinghui; Li, Enyou

    2016-01-01

    To identify the best lung ventilation strategy for acute respiratory distress syndrome (ARDS), we performed a network meta-analysis. The Cochrane Central Register of Controlled Trials, EMBASE, MEDLINE, CINAHL, and the Web of Science were searched, and 36 eligible articles were included. Compared with higher tidal volumes with FiO2-guided lower positive end-expiratory pressure [PEEP], the hazard ratios (HRs) for mortality were 0.624 (95% confidence interval (CI) 0.419-0.98) for lower tidal volumes with FiO2-guided lower PEEP and prone positioning and 0.572 (0.34-0.968) for pressure-controlled ventilation with FiO2-guided lower PEEP. Lower tidal volumes with FiO2-guided higher PEEP and prone positioning had the greatest potential to reduce mortality, and the possibility of receiving the first ranking was 61.6%. Permissive hypercapnia, recruitment maneuver, and low airway pressures were most likely to be the worst in terms of all-cause mortality. Compared with higher tidal volumes with FiO2-guided lower PEEP, pressure-controlled ventilation with FiO2-guided lower PEEP and lower tidal volumes with FiO2-guided lower PEEP and prone positioning ventilation are associated with lower mortality in ARDS patients. Lower tidal volumes with FiO2-guided higher PEEP and prone positioning ventilation and lower tidal volumes with pressure-volume (P-V) static curve-guided individual PEEP are potential optimal strategies for ARDS patients. PMID:26955891

  13. Lung ventilation strategies for acute respiratory distress syndrome: a systematic review and network meta-analysis

    PubMed Central

    Wang, Changsong; Wang, Xiaoyang; Chi, Chunjie; Guo, Libo; Guo, Lei; Zhao, Nana; Wang, Weiwei; Pi, Xin; Sun, Bo; Lian, Ailing; Shi, Jinghui; Li, Enyou

    2016-01-01

    To identify the best lung ventilation strategy for acute respiratory distress syndrome (ARDS), we performed a network meta-analysis. The Cochrane Central Register of Controlled Trials, EMBASE, MEDLINE, CINAHL, and the Web of Science were searched, and 36 eligible articles were included. Compared with higher tidal volumes with FiO2-guided lower positive end-expiratory pressure [PEEP], the hazard ratios (HRs) for mortality were 0.624 (95% confidence interval (CI) 0.419–0.98) for lower tidal volumes with FiO2-guided lower PEEP and prone positioning and 0.572 (0.34–0.968) for pressure-controlled ventilation with FiO2-guided lower PEEP. Lower tidal volumes with FiO2-guided higher PEEP and prone positioning had the greatest potential to reduce mortality, and the possibility of receiving the first ranking was 61.6%. Permissive hypercapnia, recruitment maneuver, and low airway pressures were most likely to be the worst in terms of all-cause mortality. Compared with higher tidal volumes with FiO2-guided lower PEEP, pressure-controlled ventilation with FiO2-guided lower PEEP and lower tidal volumes with FiO2-guided lower PEEP and prone positioning ventilation are associated with lower mortality in ARDS patients. Lower tidal volumes with FiO2-guided higher PEEP and prone positioning ventilation and lower tidal volumes with pressure-volume (P–V) static curve-guided individual PEEP are potential optimal strategies for ARDS patients. PMID:26955891

  14. The effects of positive end-expiratory pressure on respiratory system mechanics and hemodynamics in postoperative cardiac surgery patients.

    PubMed

    Auler, J O; Carmona, M J; Barbas, C V; Saldiva, P H; Malbouisson, L M

    2000-01-01

    We prospectively evaluated the effects of positive end-expiratory pressure (PEEP) on the respiratory mechanical properties and hemodynamics of 10 postoperative adult cardiac patients undergoing mechanical ventilation while still anesthetized and paralyzed. The respiratory mechanics was evaluated by the inflation inspiratory occlusion method and hemodynamics by conventional methods. Each patient was randomized to a different level of PEEP (5, 10 and 15 cmH2O), while zero end-expiratory pressure (ZEEP) was established as control. PEEP of 15-min duration was applied at 20-min intervals. The frequency dependence of resistance and the viscoelastic properties and elastance of the respiratory system were evaluated together with hemodynamic and respiratory indexes. We observed a significant decrease in total airway resistance (13.12 +/- 0.79 cmH2O l-1 s-1 at ZEEP, 11.94 +/- 0.55 cmH2O l-1 s-1 (P<0.0197) at 5 cmH2O of PEEP, 11.42 +/- 0.71 cmH2O l-1 s-1 (P<0.0255) at 10 cmH2O of PEEP, and 10.32 +/- 0.57 cmH2O l-1 s-1 (P<0.0002) at 15 cmH2O of PEEP). The elastance (Ers; cmH2O/l) was not significantly modified by PEEP from zero (23.49 +/- 1.21) to 5 cmH2O (21.89 +/- 0.70). However, a significant decrease (P<0.0003) at 10 cmH2O PEEP (18.86 +/- 1.13), as well as (P<0.0001) at 15 cmH2O (18.41 +/- 0.82) was observed after PEEP application. Volume dependence of viscoelastic properties showed a slight but not significant tendency to increase with PEEP. The significant decreases in cardiac index (l min-1 m-2) due to PEEP increments (3.90 +/- 0.22 at ZEEP, 3.43 +/- 0.17 (P<0. 0260) at 5 cmH2O of PEEP, 3.31 +/- 0.22 (P<0.0260) at 10 cmH2O of PEEP, and 3.10 +/- 0.22 (P<0.0113) at 15 cmH2O of PEEP) were compensated for by an increase in arterial oxygen content owing to shunt fraction reduction (%) from 22.26 +/- 2.28 at ZEEP to 11.66 +/- 1.24 at PEEP of 15 cmH2O (P<0.0007). We conclude that increments in PEEP resulted in a reduction of both airway resistance and respiratory elastance

  15. Postoperative atelectasis: Intermittent positive pressure breathing, incentive spirometry, and face-mask positive end-expiratory pressure.

    PubMed

    Paul, W L; Downs, J B

    1981-07-01

    Postoperative atelectasis has been treated with inspiratory maneuvers in an attempt to increase functional residual capacity. We compared the effect of intermittent positive pressure breathing (IPPB), incentive spirometry, and 5-cm H2O positive end-expiratory pressure (PEEP) applied with a face mask on the transpulmonary pressure (PL) at the end of expiration of eight patients 24 to 34 hours after aortocoronary bypass graft insertion. Intermittent positive pressure breathing and PEEP increased expiratory PL during therapy. After IPPB, expiratory PL fell below control values and then returned toward, but did not reach, control values After PEEP was discontinued, expiratory PL returned to control values within the next 30 minutes. The results suggest that face-mask PEEP will increase functional residual capacity, that incentive spirometry has little or effect, and that IPPB may decrease lung volume after treatment. PMID:7020643

  16. Combined Effects of Ventilation Mode and Positive End-Expiratory Pressure on Mechanics, Gas Exchange and the Epithelium in Mice with Acute Lung Injury

    PubMed Central

    Thammanomai, Apiradee; Hamakawa, Hiroshi; Bartolák-Suki, Erzsébet; Suki, Béla

    2013-01-01

    The accepted protocol to ventilate patients with acute lung injury is to use low tidal volume (VT) in combination with recruitment maneuvers or positive end-expiratory pressure (PEEP). However, an important aspect of mechanical ventilation has not been considered: the combined effects of PEEP and ventilation modes on the integrity of the epithelium. Additionally, it is implicitly assumed that the best PEEP-VT combination also protects the epithelium. We aimed to investigate the effects of ventilation mode and PEEP on respiratory mechanics, peak airway pressures and gas exchange as well as on lung surfactant and epithelial cell integrity in mice with acute lung injury. HCl-injured mice were ventilated at PEEPs of 3 and 6 cmH2O with conventional ventilation (CV), CV with intermittent large breaths (CVLB) to promote recruitment, and a new mode, variable ventilation, optimized for mice (VVN). Mechanics and gas exchange were measured during ventilation and surfactant protein (SP)-B, proSP-B and E-cadherin levels were determined from lavage and lung homogenate. PEEP had a significant effect on mechanics, gas exchange and the epithelium. The higher PEEP reduced lung collapse and improved mechanics and gas exchange but it also down regulated surfactant release and production and increased epithelial cell injury. While CVLB was better than CV, VVN outperformed CVLB in recruitment, reduced epithelial injury and, via a dynamic mechanotransduction, it also triggered increased release and production of surfactant. For long-term outcome, selection of optimal PEEP and ventilation mode may be based on balancing lung physiology with epithelial injury. PMID:23326543

  17. Comparison of the hemodynamic effects of gasless abdominal distention and CO2 pneumoperitoneum during incremental positive end-expiratory pressure.

    PubMed

    Woolley, D S; Puglisi, R N; Bilgrami, S; Quinn, J V; Slotman, G J

    1995-01-01

    Laparoscopy is used increasingly in managing critically ill patients. Carbon dioxide (CO2) pneumoperitoneum is used during these procedures. The increased intra-abdominal pressure of CO2 pneumoperitoneum, however, can affect cardiopulmonary performance adversely. Recently, gasless abdominal wall distention has been introduced as an alternative to CO2 pneumoperitoneum. The purpose of this study was to compare the hemodynamic effects of gasless abdominal distention (GAD) with those of CO2 pneumoperitoneum during mechanical ventilation with positive end-expiratory pressure (PEEP). Six anesthetized, paralyzed, mechanically ventilated adult swine were monitored with pulmonary artery and arterial catheters at incremental values of PEEP (0-20 cm H2O, by 5, Control) and then allowed to return to baseline hemodynamic status at 0 cm H2O PEEP. The animals were then randomly assigned to receive either CO2 pneumoperitoneum at 15 mm Hg intra-abdominal pressure (PNEUMO) or GAD (equal to anterior abdominal wall displacement of CO2) and PEEP was reapplied. The animals were allowed to return to hemodynamic baseline and PEEP was reapplied with the alternate method of abdominal wall distention. A complete hemodynamic profile and arterial/mixed venous blood gas measurements were monitored at each value of PEEP. With GAD, central venous pressure (CVP), pulmonary artery pressure (PAP), pulmonary capillary wedge pressure (PCWP), and PaCO2 were significantly reduced, compared to PNEUMO, and PaO2 was increased. Cardiac index was higher in GAD versus PNEUMO at baseline, but was lower for GAD at PEEP levels above 10 cm H2O. These results indicate that in its net effect, GAD does not exacerbate the adverse hemodynamic effects of PEEP.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7830409

  18. The effect of postoperative positive end-expiratory pressure on postoperative bleeding after off-pump coronary artery bypass grafting

    PubMed Central

    Salihoglu, Ece; Celik, Sezai; Ugurlucan, Murat; Caglar, Ilker Murat; Turhan-Caglar, Fatma Nihan; Isik, Omer

    2014-01-01

    Introduction To compare postoperative prophylactic use of two positive end-expiratory pressure (PEEP) levels in order to prevent postoperative bleeding in patients undergoing off-pump coronary artery bypass grafting (CABG) surgery. Material and methods Sixty patients undergoing an elective off-pump CABG operation were included in this prospective, nonrandomized clinical trial. Patients were divided into two groups as receiving either 5 cm H2O (group 1) or 8 cm H2O PEEP (group 2) after the operation until being extubated. Chest tube outputs, use of blood products and other fluids, postoperative hemoglobin levels, accumulation of pleural and pericardial fluid after the removal of chest tubes, and duration of hospital stay were recorded and compared. Results Low- and high-pressure PEEP groups did not differ with regard to postoperative chest tube outputs, amounts of transfusions and crystalloid/colloid infusion requirements, or postoperative hemoglobin levels. However, low-pressure PEEP application was associated with significantly higher pleural (92 ±37 ml vs. 69 ±29 ml, p = 0.03) and pericardial fluid (17 ±5 ml vs. 14 ±6 ml, p = 0.04) accumulation. On the other hand, high-pressure PEEP application was associated with significantly longer duration of hospitalization (6.25 ±1.21 days vs. 5.25 ±0.91 days, p = 0.03). Conclusions Prophylactic administration of postoperative PEEP levels of 8 cm H2O, although safe, does not seem to reduce chest-tube output or transfusion requirements in off-pump CABG when compared to the lower level of PEEP. Further studies with larger sample sizes are warranted to confirm the benefits and identify ideal levels of PEEP administration in this group of patients. PMID:25395944

  19. Effects of the Trendelenburg Position and Positive End-Expiratory Pressure on the Internal Jugular Vein Cross-Sectional Area in Children With Simple Congenital Heart Defects

    PubMed Central

    Kim, Hee Yeong; Choi, Jae Moon; Lee, Yong-Hun; Lee, Sukyung; Yoo, Hwanhee; Gwak, Mijeung

    2016-01-01

    Abstract Catheterization of the internal jugular vein (IJV) remains difficult in pediatric populations. Increasing the cross-sectional area (CSA) of the IJV facilitates cannulation and decreases complications. We aimed to evaluate the Trendelenburg position and the levels of positive end-expiratory pressure (PEEP) at which the maximum increase of CSA of the IJV occurred in children undergoing cardiac surgery. In this prospective study, the CSA of the right IJV was assessed using ultrasound in 47 anesthetized pediatric patients with simple congenital heart defects. The baseline CSA was obtained in response to a supine position with no PEEP and compared with 5 different randomly ordered maneuvers, that is, a PEEP of 5 and 10 cm H2O in a supine position and of 0, 5, and 10 cm H2O in a 10° Trendelenburg position. Hemodynamic variables, including blood pressure and heart rate, maximum and minimum diameters, and CSA, were measured. All maneuvers increased the CSA of the right IJV with respect to the control condition. In the supine position, the CSA was increased by 9.4% with a PEEP of 5 and by 19.5% with a PEEP of 10 cm H2O. The Trendelenburg tilt alone increased the CSA by 19.0%, and combining the 10° Trendelenburg with a 10 cm H2O PEEP resulted in the largest IJV CSA increase (33.3%) compared with the supine position with no PEEP. Meanwhile, vital signs remained relatively steady during the experiment. The application of the Trendelenburg position and a 10 cm H2O PEEP thus significantly increases the CSA of the right IJV, perhaps improving the chances of successful cannulation in pediatric patients with simple congenital heart defects. PMID:27149455

  20. Effects of the Trendelenburg Position and Positive End-Expiratory Pressure on the Internal Jugular Vein Cross-Sectional Area in Children With Simple Congenital Heart Defects.

    PubMed

    Kim, Hee Yeong; Choi, Jae Moon; Lee, Yong-Hun; Lee, Sukyung; Yoo, Hwanhee; Gwak, Mijeung

    2016-05-01

    Catheterization of the internal jugular vein (IJV) remains difficult in pediatric populations. Increasing the cross-sectional area (CSA) of the IJV facilitates cannulation and decreases complications. We aimed to evaluate the Trendelenburg position and the levels of positive end-expiratory pressure (PEEP) at which the maximum increase of CSA of the IJV occurred in children undergoing cardiac surgery.In this prospective study, the CSA of the right IJV was assessed using ultrasound in 47 anesthetized pediatric patients with simple congenital heart defects. The baseline CSA was obtained in response to a supine position with no PEEP and compared with 5 different randomly ordered maneuvers, that is, a PEEP of 5 and 10 cm H2O in a supine position and of 0, 5, and 10 cm H2O in a 10° Trendelenburg position. Hemodynamic variables, including blood pressure and heart rate, maximum and minimum diameters, and CSA, were measured.All maneuvers increased the CSA of the right IJV with respect to the control condition. In the supine position, the CSA was increased by 9.4% with a PEEP of 5 and by 19.5% with a PEEP of 10 cm H2O. The Trendelenburg tilt alone increased the CSA by 19.0%, and combining the 10° Trendelenburg with a 10 cm H2O PEEP resulted in the largest IJV CSA increase (33.3%) compared with the supine position with no PEEP. Meanwhile, vital signs remained relatively steady during the experiment.The application of the Trendelenburg position and a 10 cm H2O PEEP thus significantly increases the CSA of the right IJV, perhaps improving the chances of successful cannulation in pediatric patients with simple congenital heart defects. PMID:27149455

  1. Combined effects of ventilation mode and positive end-expiratory pressure on mechanics, gas exchange and the epithelium in mice with acute lung injury.

    PubMed

    Thammanomai, Apiradee; Hamakawa, Hiroshi; Bartolák-Suki, Erzsébet; Suki, Béla

    2013-01-01

    The accepted protocol to ventilate patients with acute lung injury is to use low tidal volume (V(T)) in combination with recruitment maneuvers or positive end-expiratory pressure (PEEP). However, an important aspect of mechanical ventilation has not been considered: the combined effects of PEEP and ventilation modes on the integrity of the epithelium. Additionally, it is implicitly assumed that the best PEEP-V(T) combination also protects the epithelium. We aimed to investigate the effects of ventilation mode and PEEP on respiratory mechanics, peak airway pressures and gas exchange as well as on lung surfactant and epithelial cell integrity in mice with acute lung injury. HCl-injured mice were ventilated at PEEPs of 3 and 6 cmH(2)O with conventional ventilation (CV), CV with intermittent large breaths (CV(LB)) to promote recruitment, and a new mode, variable ventilation, optimized for mice (VV(N)). Mechanics and gas exchange were measured during ventilation and surfactant protein (SP)-B, proSP-B and E-cadherin levels were determined from lavage and lung homogenate. PEEP had a significant effect on mechanics, gas exchange and the epithelium. The higher PEEP reduced lung collapse and improved mechanics and gas exchange but it also down regulated surfactant release and production and increased epithelial cell injury. While CV(LB) was better than CV, VV(N) outperformed CV(LB) in recruitment, reduced epithelial injury and, via a dynamic mechanotransduction, it also triggered increased release and production of surfactant. For long-term outcome, selection of optimal PEEP and ventilation mode may be based on balancing lung physiology with epithelial injury. PMID:23326543

  2. Changes in intrathoracic pressures induced by positive end-expiratory pressure ventilation after cardiac surgical procedures.

    PubMed

    Bonnet, F; Fischler, M; Dubois, C L; Brodaty, D; Pluskwa, F; Guilmet, D; Vourc'h, G

    1986-10-01

    The consequences of controlled ventilation with positive end-expiratory pressure (PEEP) were studied, after cardiac surgical procedures, in two groups of patients supposed to have different lung and chest wall mechanical properties. The first group included 6 patients who had undergone coronary artery graft surgical procedures (CGS). The second group included 5 patients who had undergone a mitral valve replacement (MVR). Postoperatively, static lung and chest wall compliance was measured by stepwise inflation and deflation of the thorax. Esophageal, pericardial, and pleural pressures were then measured, and cardiac output was determined while PEEP was increased from 0 to 20 cm H2O. Lung and chest wall compliance values sharply decreased in MVR patients. This accounts for the lower values for pleural and pericardial pressures in this group than in the CGS patient group, but the transmission of airway pressure was identical in the two groups when PEEP was increased. The decrease in cardiac output induced by PEEP was similar in the two groups. The results suggest that the opposing influences of lung and chest wall compliance on airway pressure transmission could at least partly explain the hemodynamic effects of PEEP in patients in whom the mechanical properties of the lung and thorax are impaired. PEEP ventilation should be used cautiously in patients suspected of having thoracic rigidity. PMID:3532981

  3. The effect of positive end-expiratory pressure on regional ventilation and perfusion in the normal and injured primate lung.

    PubMed

    Hammon, J W; Wolfe, W G; Moran, J F; Jones, R H; Sabiston, D C

    1976-11-01

    Although positive end-expiratory pressure (PEEP) is being employed in the management of respiratory insufficiency, many of its physiological effects remain undetermined. The cardiopulmonary effects of PEEP as well as its effect on regional ventilation and perfusion were studied in 10 baboons before and after pulmonary injury with oleic acid. In the normal lung, there was significant improvement in oxygenation at a PEEP of 5 cm. of water secondary to improved ventilation and perfusion in all PEEP greater than 5 cm. of water produced increasing mismatch of ventilation and perfusion in all zones. After oleic acid was injected, hypoxemia was evident with a reversal of the normal ventilation-perfusion (V/Q) relationship between upper and lower lung zones. This mismatch of ventilation and perfusion was corrected at a PEEP of 15 cm. of water. It was reasonable to conclude that the use of PEEP in the injured lung exerts it beneficial effect by balancing regional ventilation and perfusion in addition to increasing functional residual capacity. PMID:824505

  4. Differing responses in right and left ventricular filling, loading and volumes during positive end-expiratory pressure

    SciTech Connect

    Schulman, D.S.; Biondi, J.W.; Matthay, R.A.; Zaret, B.L.; Soufer, R. )

    1989-10-01

    Using a combined hemodynamic and radionuclide technique, 20 patients with varied ventricular function were evaluated during positive end-expiratory pressure (PEEP) application. Left ventricular (LV) and right ventricular (RV) ejection fractions and cardiac output were measured, and ventricular volumes were derived. Seven patients (group 1) who had an increase in LV end-diastolic volume with PEEP and 13 patients (group 2) who had the more typical response, a decrease in LV end-diastolic volume with PEEP, were identified. Compared with group 2, group 1 patients had a higher incidence of coronary artery disease (5 of 7 vs 1 of 13, p less than 0.005) and lower cardiac output (3.9 +/- 1.6 vs 9.1 +/- 3.2 liters/min, p less than 0.005), LV ejection fraction (27 +/- 13 vs 51 +/- 21%, p less than 0.05), RV ejection fraction (15 +/- 6 vs 32 +/- 8%, p less than 0.005) and peak filling rate (1.32 +/- 0.43 vs 3.51 +/- 1.70 end-diastolic volumes/s, p less than 0.05). LV and RV volumes increased and peak filling rate decreased with PEEP in group 1, whereas in group 2 LV volume decreased and RV volume and peak filling rate remained unchanged. Using stepwise regression analysis, the change in LV volume with PEEP was related directly to baseline systemic vascular resistance and inversely to baseline blood pressure. Similarly, the change in peak filling rate with PEEP was inversely related to the change in RV end-diastolic volume. Thus, the hemodynamic response to PEEP is heterogeneous and may be related to LV ischemia.

  5. Positive End-expiratory Pressure Titration after Alveolar Recruitment Directed by Electrical Impedance Tomography

    PubMed Central

    Long, Yun; Liu, Da-Wei; He, Huai-Wu; Zhao, Zhan-Qi

    2015-01-01

    Background: Electrical impedance tomography (EIT) is a real-time bedside monitoring tool, which can reflect dynamic regional lung ventilation. The aim of the present study was to monitor regional gas distribution in patients with acute respiratory distress syndrome (ARDS) during positive-end-expiratory pressure (PEEP) titration using EIT. Methods: Eighteen ARDS patients under mechanical ventilation in Department of Critical Care Medicine of Peking Union Medical College Hospital from January to April in 2014 were included in this prospective observational study. After recruitment maneuvers (RMs), decremental PEEP titration was performed from 20 cmH2O to 5 cmH2O in steps of 3 cmH2O every 5–10 min. Regional over-distension and recruitment were monitored with EIT. Results: After RMs, patient with arterial blood oxygen partial pressure (PaO2) + carbon dioxide partial pressure (PaCO2) >400 mmHg with 100% of fractional inspired oxygen concentration were defined as RM responders. Thirteen ARDS patients was diagnosed as responders whose PaO2 + PaCO2 were higher than nonresponders (419 ± 44 mmHg vs. 170 ± 73 mmHg, P < 0.0001). In responders, PEEP mainly increased recruited pixels in dependent regions and over-distended pixels in nondependent regions. PEEP alleviated global inhomogeneity of tidal volume and end-expiratory lung volume. PEEP levels without significant alveolar derecruitment and over-distension were identified individually. Conclusions: After RMs, PEEP titration significantly affected regional gas distribution in lung, which could be monitored with EIT. EIT has the potential to optimize PEEP titration. PMID:26021494

  6. Mechanical ventilation with positive end-expiratory pressure decreases the circulating concentrations of the N-terminus and C-terminus of the atrial natriuretic factor prohormone.

    PubMed

    Vesely, D L; Salmon, J S

    1990-01-01

    Mechanical ventilation with positive end-expiratory pressure (PEEP) decreases urine output and urinary sodium excretion. The influence of PEEP during controlled mechanical ventilation on the circulating concentrations of the N-terminus and C-terminus of the atrial natriuretic factor (ANF) prohormone which both contain natriuretic and diuretic peptides was investigated in 7 patients with acute respiratory failure. The 98 amino acid (aa) N-terminus, the midportion of the N-terminus consisting of aa 31-67 of the 126 aa ANF prohormone (i.e., pro ANF 31-67) and the C-terminus (aa 99-126; ANF) were found to be significantly (p less than 0.05; ANOVA) elevated compared to 54 healthy volunteers during acute respiratory failure prior to institution of PEEP. With institution of 10 cm of H2O of PEEP all 7 patients had a significant (p less than 0.05) decrease in the circulating concentrations of pro ANFs 1-98, 31-67 and ANF. These findings suggest that the increased thoracic pressure secondary to PEEP which reduces venous return and lowers atrial filling pressure results in a decreased release of the N-terminus and C-terminus of the ANF prohormone. This decrease in the N-terminus and C-terminus of the ANF prohormone appears to represent a physiologic mechanism for restoration of intravascular volume, secondary to decreased sodium excretion. PMID:2151585

  7. Setting ventilation parameters guided by electrical impedance tomography in an animal trial of acute respiratory distress syndrome

    NASA Astrophysics Data System (ADS)

    Czaplik, Michael; Biener, Ingeborg; Leonhardt, Steffen; Rossaint, Rolf

    2014-03-01

    Since mechanical ventilation can cause harm to lung tissue it should be as protective as possible. Whereas numerous options exist to set ventilator parameters, an adequate monitoring is lacking up to date. The Electrical Impedance Tomography (EIT) provides a non-invasive visualization of ventilation which is relatively easy to apply and commercially available. Although there are a number of published measures and parameters derived from EIT, it is not clear how to use EIT to improve clinical outcome of e.g. patients suffering from acute respiratory distress syndrome (ARDS), a severe disease with a high mortality rate. On the one hand, parameters should be easy to obtain, on the other hand clinical algorithms should consider them to optimize ventilator settings. The so called Global inhomogeneity (GI) index bases on the fact that ARDS is characterized by an inhomogeneous injury pattern. By applying positive endexpiratory pressures (PEEP), homogeneity should be attained. In this study, ARDS was induced by a double hit procedure in six pigs. They were randomly assigned to either the EIT or the control group. Whereas in the control group the ARDS network table was used to set the PEEP according to the current inspiratory oxygen fraction, in the EIT group the GI index was calculated during a decremental PEEP trial. PEEP was kept when GI index was lowest. Interestingly, PEEP was significantly higher in the EIT group. Additionally, two of these animals died ahead of the schedule. Obviously, not only homogeneity of ventilation distribution matters but also limitation of over-distension.

  8. Positional effects on distribution of ventilation in chronic obstructive pulmonary disease

    SciTech Connect

    Shim, C.; Chun, K.J.; Williams, M.H. Jr.; Blaufox, M.D.

    1986-09-01

    Ventilation is distributed predominantly to the dependent lung in normal persons in the decubitus position. We evaluated the distribution of ventilation in four patients with mild-to-moderate chronic obstructive pulmonary disease using 81mKr gas. Patients were tested in the sitting and right and left decubitus positions with and without the application of positive end expiratory pressure (PEEP). In contrast to findings in controls, ventilation was predominantly distributed to the nondependent lung in patients in the decubitus position. Mean ventilation in the right lung decreased from 51% of the total in the sitting position to 31% in the right decubitus position; it increased with the application of 10 cm PEEP. Reduced ventilation in the dependent lung most likely is caused by closure of the airways after a decrease in volume. Application of PEEP resulted in increased lung volume and preferential distribution of ventilation to the dependent lung.

  9. Final postflight hardware evaluation report RSRM-32 (STS-57)

    NASA Astrophysics Data System (ADS)

    Nielson, Greg

    1993-11-01

    This document is the final report for the postflight assessment of the RSRM-32 (STS-57) flight set. This report presents the disassembly evaluations performed at the Thiokol facilities in Utah and is a continuation of the evaluations performed at KSC (TWR-64239). The PEEP for this assessment is outlined in TWR-50051, Revision B. The PEEP defines the requirements for evaluating RSRM hardware. Special hardware issues pertaining to this flight set requiring additional or modified assessment are outlined in TWR-64237. All observed hardware conditions were documented on PFOR's which are included in Appendix A. Observations were compared against limits defined in the PEEP. Any observation that was categorized as reportable or had no defined limits was documented on a preliminary PFAR by the assessment engineers. Preliminary PFAR's were reviewed by the Thiokol SPAT Executive Board to determine if elevation to PFAR's was required.

  10. Individualized positive end-expiratory pressure application in patients with acute respiratory distress syndrome.

    PubMed

    Pintado, M C; de Pablo, R

    2014-11-01

    Current treatment of acute respiratory distress syndrome is based on ventilatory support with a lung protective strategy, avoiding the development of iatrogenic injury, including ventilator-induced lung injury. One of the mechanisms underlying such injury is atelectrauma, and positive end-expiratory pressure (PEEP) is advocated in order to avoid it. The indicated PEEP level has not been defined, and in many cases is based on the patient oxygen requirements for maintaining adequate oxygenation. However, this strategy does not consider the mechanics of the respiratory system, which varies in each patient and depends on many factors-including particularly the duration of acute respiratory distress syndrome. A review is therefore made of the different methods for adjusting PEEP, focusing on the benefits of individualized application. PMID:24485531

  11. [Comprehensive Toxicity Evaluation and Toxicity Identification Used in Tannery and Textile Wastewaters].

    PubMed

    Huang, Li; Chen, Wen-yan; Wan, Yu-shan; Zheng, Guo-juan; Zhao, Yuan; Cai, Qiang

    2015-07-01

    To better evaluate the toxicity of tannery and textile effluents from various emission stages, the research attempted battery of toxicological bioassays and toxicological indices. The bioassays employed Microtox test, zebra fish embryo-larval test and algae (Chlorella vulgaris) test. Meanwhile, toxicological indices including Toxicity Unit (TU), Average Toxicity (AvTx), Toxic Print (TxPr), Most Sensitive Test (MST) and Potential Ecotoxic Effects Probe (PEEP) were applied. The results illustrated that PEEP was the most comprehensive index to take account of the emissions and toxic potential of effluents. PEEP values showed that the reduction rates of toxicity in tannery and textile effluents were 36. 8% and 23. 2%, respectively. Finally, based on the Microtox toxicity test, toxicants in textile effluent were identified through the toxicity identification evaluation (TIE) studies. The results indicated that the main toxicant of textile effluent was non-polar organic pollutants, followed by filterable compounds, heavy metals, oxidizing substances and volatile components. PMID:26489331

  12. Final postflight hardware evaluation report RSRM-32 (STS-57)

    NASA Technical Reports Server (NTRS)

    Nielson, Greg

    1993-01-01

    This document is the final report for the postflight assessment of the RSRM-32 (STS-57) flight set. This report presents the disassembly evaluations performed at the Thiokol facilities in Utah and is a continuation of the evaluations performed at KSC (TWR-64239). The PEEP for this assessment is outlined in TWR-50051, Revision B. The PEEP defines the requirements for evaluating RSRM hardware. Special hardware issues pertaining to this flight set requiring additional or modified assessment are outlined in TWR-64237. All observed hardware conditions were documented on PFOR's which are included in Appendix A. Observations were compared against limits defined in the PEEP. Any observation that was categorized as reportable or had no defined limits was documented on a preliminary PFAR by the assessment engineers. Preliminary PFAR's were reviewed by the Thiokol SPAT Executive Board to determine if elevation to PFAR's was required.

  13. Continuum and molecular-dynamics simulation of nanodroplet collisions

    NASA Astrophysics Data System (ADS)

    Bardia, Raunak; Liang, Zhi; Keblinski, Pawel; Trujillo, Mario F.

    2016-05-01

    The extent to which the continuum treatment holds in binary droplet collisions is examined in the present work by using a continuum-based implicit surface capturing strategy (volume-of-fluid coupled to Navier-Stokes) and a molecular dynamics methodology. The droplet pairs are arranged in a head-on-collision configuration with an initial separation distance of 5.3 nm and a velocity of 3 ms-1. The size of droplets ranges from 10-50 nm. Inspecting the results, the collision process can be described as consisting of two periods: a preimpact phase that ends with the initial contact of both droplets, and a postimpact phase characterized by the merging, deformation, and coalescence of the droplets. The largest difference between the continuum and molecular dynamics (MD) predictions is observed in the preimpact period, where the continuum-based viscous and pressure drag forces significantly overestimate the MD predictions. Due to large value of Knudsen number in the gas (Kngas=1.972 ), this behavior is expected. Besides the differences between continuum and MD, it is also observed that the continuum simulations do not converge for the set of grid sizes considered. This is shown to be directly related to the initial velocity profile and the minute size of the nanodroplets. For instance, for micrometer-size droplets, this numerical sensitivity is not an issue. During the postimpact period, both MD and continuum-based simulations are strikingly similar, with only a moderate difference in the peak kinetic energy recorded during the collision process. With values for the Knudsen number in the liquid (Knliquid=0.01 for D =36 nm ) much closer to the continuum regime, this behavior is expected. The 50 nm droplet case is sufficiently large to be predicted reasonably well with the continuum treatment. However, for droplets smaller than approximately 36 nm, the departure from continuum behavior becomes noticeably pronounced, and becomes drastically different for the 10 nm droplets.

  14. The simultaneous application of positive-end expiratory pressure with the Trendelenburg position minimizes respiratory fluctuations in internal jugular vein size

    PubMed Central

    Han, Sun Sook; Han, Woong Ki; Ko, Dong Chan

    2014-01-01

    Background The respiratory cycle alters the size of the right internal jugular vein (RIJV). We assessed the changes in RIJV size during the respiratory cycle in patients under positive pressure ventilation. Moreover, we examined the effects of positive-end expiratory pressure (PEEP) and the Trendelenburg position on respiratory fluctuations. Methods A prospective study of 24 patients undergoing general endotracheal anesthesia was performed. Images of the RIJV were obtained in the supine position with no PEEP (baseline, S0) and after applying three different maneuvers in random order: (1) a PEEP of 10 cmH2O (S10), (2) a 10° Trendelenburg tilt position (T0), and (3) a 10° Trendelenburg tilt position combined with a PEEP of 10 cmH2O (T10). Using the images when the area was smallest and largest, cross-sectional area (CSA), anteroposterior diameter, and transverse diameter were measured. Results All maneuvers minimized the fluctuation in RIJV size (all P = 0.0004). During the respiratory cycle, the smallest CSA compared to the largest CSA at S0, S10, T0, and T10 decreased by 28.3 8.5, 8.0, and 4.4%, respectively. Furthermore, compared to S0, a 10° Trendelenburg tilt position with a PEEP of 10 cmH2O significantly increased the CSA in the largest areas by 83.8% and in the smallest areas by 169.4%. Conclusions A 10° Trendelenburg tilt position combined with a PEEP of 10 cmH2O not only increases the size of the RIJV but also reduces fluctuation by the respiratory cycle. PMID:24910725

  15. Effects of Alveolar Recruitment and Positive End-Expiratory Pressure on Oxygenation during One-Lung Ventilation in the Supine Position

    PubMed Central

    Choi, Yong Seon; Bae, Mi Kyung; Kim, Shin Hyung; Park, Ji-Eun; Kim, Soo Young

    2015-01-01

    Purpose Hypoxemia during one-lung ventilation (OLV) remains a serious problem, particularly in the supine position. We investigated the effects of alveolar recruitment (AR) and positive end-expiratory pressure (PEEP) on oxygenation during OLV in the supine position. Materials and Methods Ninety-nine patients were randomly allocated to one of the following three groups: a control group (ventilation with a tidal volume of 8 mL/kg), a PEEP group (the same ventilatory pattern with a PEEP of 8 cm H2O), or an AR group (an AR maneuver immediately before OLV followed by a PEEP of 8 cm H2O). The tidal volume was reduced to 6 mL/kg during OLV in all groups. Blood gas analyses, respiratory variables, and hemodynamic variables were recorded 15 min into TLV (TLVbaseline), 15 and 30 min after OLV (OLV15 and OLV30), and 10 min after re-establishing TLV (TLVend). Results Ultimately, 92 patients were analyzed. In the AR group, the arterial oxygen tension was higher at TLVend, and the physiologic dead space was lower at OLV15 and TLVend than in the control group. The mean airway pressure and dynamic lung compliance were higher in the PEEP and AR groups than in the control group at OLV15, OLV30, and TLVend. No significant differences in hemodynamic variables were found among the three groups throughout the study period. Conclusion Recruitment of both lungs with subsequent PEEP before OLV improved arterial oxygenation and ventilatory efficiency during video-assisted thoracic surgery requiring OLV in the supine position. PMID:26256990

  16. The effect of positive end-expiratory pressure on inflammatory cytokines during laparoscopic cholecystectomy

    PubMed Central

    Yılmazlar, Firdevs; Karabayırlı, Safinaz; Gözdemir, Muhammet; Usta, Burhanettin; Peker, Murat; Namuslu, Mehmet; Erdamar, Hüsamettin

    2015-01-01

    Objectives: To investigate effects of the positive end-expiratory pressure (PEEP) application of 10 cm H2O on the plasma levels of cytokines during laparoscopic cholecystectomy. Methods: A prospective study was conducted on 40 patients who presented to the Department of General Surgery, Medical Faculty, Turgut Özal University, Ankara, Turkey scheduled for laparoscopic cholecystectomy operation during a 10 month period from September 2012 to June 2013. Forty patients scheduled for laparoscopic cholecystectomy operation were randomly divided into 2 groups; ventilation through zero end-expiratory pressure (ZEEP) (0 cm H2O PEEP) (n=20), and PEEP (10 cm H2O PEEP) (n=20). All patients were ventilated with 8 ml/kg TV. Levels of interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL 10, and transforming growth factor (TGF)-β1 were measured in the pre- and post-operatively collected samples. Results: Blood samples of 30 patients’ were analyzed for plasma cytokine levels, and 10 were excluded from the study due to hemolysis. Post-operative plasma IL-6 levels were observed to be significantly higher than the pre-operative patients (p=0.035). Post-operative plasma TGF-β1 levels in the PEEP group was found significantly higher compared with the pre-operative group levels (p=0.033). However, there were no significant differences in the pre- and post-operative plasma cytokine levels between the 2 groups. Conclusion: The application of PEEP of 10 cm H2O, which has known beneficial effect on respiratory mechanics, does not have any effect on systemic inflammatory response undergoing pneumoperitoneum during laparoscopic cholecystectomy surgery. PMID:26593173

  17. How ARDS should be treated.

    PubMed

    Gattinoni, Luciano; Quintel, Michael

    2016-01-01

    The Berlin definition criteria applied at positive end-expiratory pressure (PEEP) 5 cm H2O reasonably predict lung edema and recruitabilty. To maintain viable gas exchange, the mechanical ventilation becomes progressively more risky going from mild to severe acute respiratory distress syndrome (ARDS). Tidal volume, driving pressure, flow, and respiratory rate have been identified as causes of ventilation-induced lung injury. Taken together, they represent the mechanical power applied to the lung parenchyma. In an inhomogeneous lung, stress risers locally increase the applied mechanical power. Increasing lung homogeneity by PEEP and prone position decreases the harm of mechanical ventilation, particularly in severe ARDS. PMID:27048605

  18. [Additional gadget for new techniques of artifical respiration with the Bennett repirator PR 2, particulary suitable for use in children (author's transl)].

    PubMed

    Lang, V O

    1975-01-01

    A new gadget for the Bennett PR 2 repirator is described which in modified form can also be used with other types of apparatus. It makes possible new techniques of artificial respiration like IPPB with PEEP or compensated PEEP, the gasp respiration with CPAP or CPAP by itself, in a simple way. In neonates one may do without the often problematical assisted respiration when weaning from the respirator. Further it is now possible to achieve sufficient warming and humidification of the gas mixture by using an auxiliary gas flow in the expiratory phase. PMID:1091773

  19. Perioperative lung injury.

    PubMed

    Slinger, Peter

    2008-03-01

    Patients are at risk for several types of lung injury in the perioperative period. These injuries include atelectasis, pneumonia, pneumothorax, bronchopleural fistula, acute lung injury and acute respiratory distress syndrome. Anesthetic management can cause, exacerbate or ameliorate most of these injuries. Clinical research trends show that traditional protocols for perioperative mechanical ventilation, using large tidal volumes without positive end-expiratory pressure (PEEP) can cause a sub-clinical lung injury and this injury becomes clinically important when any additional lung injury is added. Lung-protective ventilation strategies using more physiologic tidal volumes and appropriate levels of PEEP can decrease the extent of this injury. PMID:18494396

  20. Recruitment maneuver: RAMP versus CPAP pressure profile in a model of acute lung injury.

    PubMed

    Riva, D R; Contador, R S; Baez-Garcia, C S N; Xisto, D G; Cagido, V R; Martini, S V; Morales, M M; Rocco, P R M; Faffe, D S; Zin, W A

    2009-10-31

    We examined whether recruitment maneuvers (RMs) with gradual increase in airway pressure (RAMP) provide better outcome than continuous positive airway pressure (CPAP) in paraquat-induced acute lung injury (ALI). Wistar rats received saline intraperitoneally (0.5 mL, CTRL) or paraquat (15 mg/kg, ALI). Twenty-four hours later lung mechanics [static elastance, viscoelastic component of elastance, resistive, viscoelastic and total pressures] were determined before and after recruitment with 40cmH2O CPAP for 40s or 40-s-long slow increase in pressure up to 40cmH2O (RAMP) followed by 0 or 5 cmH2O PEEP. Fractional area of alveolar collapse and PCIII mRNA were determined. All mechanical parameters and the fraction area of alveolar collapse were higher in ALI compared to CTRL. Only RAMP-PEEP maneuver significantly improved lung mechanics and decreased PCIII mRNA expression (53%) compared with ALI, while both RMs followed by PEEP decreased alveolar collapse. In conclusion, in the present experimental ALI model, RAMP followed by 5cm H2O PEEP yields a better outcome. PMID:19712760

  1. Piedmont Export Expansion Program Monograph: A Final Report.

    ERIC Educational Resources Information Center

    Brown, Ralph W., Jr.; Peniche, Eduardo A.

    The Piedmont Export Expansion Program (PEEP) was developed to increase the number of businesses in central Virginia entering or expanding export trade; to increase the utilization of the services of Central Virginia Community College's (CVCC's) Cross-Cultural and Foreign Language Resource Center by area export businesses; to increase the number of…

  2. Effects of Cued Modelling Procedures and Self-Confrontation in a Microteaching Setting Aimed at Developing Non-Verbal Behavior.

    ERIC Educational Resources Information Center

    Brusling, Christer

    The general purposes of this project were to test microteaching procedures for teacher training and to study relations between the process of teaching and its outcome. The project made use of "cued" video models (a short peep being superimposed whenever the model demonstrated a goal-related behavior), videotape self-feedback with self-evaluation…

  3. Radioaerosol delivery and clearance in patients with respiratory failure

    SciTech Connect

    Jacobs, M.P.; Tennenberg, S.D.; Baughman, R.P.

    1987-12-01

    A technique for radioaerosol delivery to patients requiring mechanical ventilation is described. Ventilation images and pulmonary radioaerosol clearance rates were successfully obtained in 35 patients regardless of ventilator type or level of positive end-expiratory pressure (PEEP). Those patients with noncardiogenic pulmonary edema (NPE) had significantly increased clearance rates relative to those patients in whom NPE was not present.

  4. Aspects of Quantum Gravity in Cosmology

    NASA Astrophysics Data System (ADS)

    Rinaldi, Massimiliano

    We review some aspects of quantum gravity in the context of cosmology. In particular, we focus on models with a phenomenology accessible to current and near-future observations, as the early Universe might be our only chance to peep through the quantum gravity realm.

  5. Formative Evaluation of Lectures; An Application of Stake's Evaluation Framework.

    ERIC Educational Resources Information Center

    Westphal, Walter W.; And Others

    The problem of major concern to the Physics Education Evaluation Project (P.E.E.P.) involved the improvement of university physics teaching and learning. The present paper describes instruments and procedures developed for systematic formative evaluation of physics lectures. The data was drawn from two sections of a first year university physics…

  6. Early Phonological Development: Creating an Assessment Test

    ERIC Educational Resources Information Center

    Stoel-Gammon, Carol; Williams, A. Lynn

    2013-01-01

    This paper describes a new protocol for assessing the phonological systems of two-year-olds with typical development and older children with delays in vocabulary acquisition. The test (Profiles of Early Expressive Phonological Skills ("PEEPS"), Williams & Stoel-Gammon, in preparation) differs from currently available assessments in that age of…

  7. Effects of Lung Expansion Therapy on Lung Function in Patients with Prolonged Mechanical Ventilation

    PubMed Central

    Chen, Yen-Huey; Yeh, Ming-Chu; Hu, Han-Chung; Lee, Chung-Shu; Li, Li-Fu; Chen, Ning-Hung; Huang, Chung-Chi; Kao, Kuo-Chin

    2016-01-01

    Common complications in PMV include changes in the airway clearance mechanism, pulmonary function, and respiratory muscle strength, as well as chest radiological changes such as atelectasis. Lung expansion therapy which includes IPPB and PEEP prevents and treats pulmonary atelectasis and improves lung compliance. Our study presented that patients with PMV have improvements in lung volume and oxygenation after receiving IPPB therapy. The combination of IPPB and PEEP therapy also results in increase in respiratory muscle strength. The application of IPPB facilitates the homogeneous gas distribution in the lung and results in recruitment of collapsed alveoli. PEEP therapy may reduce risk of respiratory muscle fatigue by preventing premature airway collapse during expiration. The physiologic effects of IPPB and PEEP may result in enhancement of pulmonary function and thus increase the possibility of successful weaning from mechanical ventilator during weaning process. For patients with PMV who were under the risk of atelectasis, the application of IPPB may be considered as a supplement therapy for the enhancement of weaning outcome during their stay in the hospital.

  8. Pulmonary clearance of radiotracers after positive end-expiratory pressure or acute lung injury

    SciTech Connect

    Barrowcliffe, M.P.; Zanelli, G.D.; Jones, J.G.

    1989-01-01

    In anesthetized rabbits we measured clearance from lung to blood of eight aerosolized technetium-99m-labeled compounds: diethylenetriaminepentaacetate (99mTc-DTPA); cytochrome c; myoglobin; a myoglobin polymer; albumin; and anionic, cationic, and neutral dextrans of equivalent molecular size. We investigated the effect of applying positive end-expiratory pressure (PEEP) and, on a subsequent occasion, of injecting oleic acid intravenously to produce acute lung injury on the pulmonary clearance rate. Base-line clearance rates were monoexponential and varied with the molecular weights of the radiotracers. For each tracer the rate of clearance was increased a similar degree by either PEEP or oleic acid. However, with PEEP, clearance remained monoexponential, whereas after oleic acid, smaller molecular-weight radiotracers had multiexponential clearance curves. This suggests that after oleic acid the alveolar epithelium breaks down in a nonuniform fashion. We conclude that differentiation of the effect of PEEP from that of severe lung injury caused by oleic acid is not readily accomplished by either increasing the size of the tracer molecule or by varying the molecular charge.

  9. Recruitment Maneuver Does not Increase the Risk of Ventilator Induced Lung Injury

    PubMed Central

    Akıncı, İbrahim Özkan; Atalan, Korkut; Tuğrul, Simru; Özcan, Perihan Ergin; Yılmazbayhan, Dilek; Kıran, Bayram; Basel, Ahmet; Telci, Lutfi; Çakar, Nahit

    2013-01-01

    Background: Mechanical ventilation (MV) may induce lung injury. Aims: To assess and evaluate the role of different mechanical ventilation strategies on ventilator-induced lung injury (VILI) in comparison to a strategy which includes recruitment manoeuvre (RM). Study design: Randomized animal experiment. Methods: Thirty male Sprague-Dawley rats were anaesthetised, tracheostomised and divided into 5 groups randomly according to driving pressures; these were mechanically ventilated with following peak alveolar opening (Pao) and positive end-expiratory pressures (PEEP) for 1 hour: Group 15-0: 15 cmH2O Pao and 0 cmH2O PEEP; Group 30-10: 30 cmH2O Pao and 10 cmH2O PEEP; Group 30-5: 30 cmH2O Pao and 5 cmH2O PEEP; Group 30-5&RM: 30 cmH2O Pao and 5 cmH2O PEEP with additional 45 cmH2O CPAP for 30 seconds in every 15 minutes; Group 45-0: 45 cmH2O Pao and 0 cmH2O PEEP Before rats were sacrificed, blood samples were obtained for the evaluation of cytokine and chemokine levels; then, the lungs were subsequently processed for morphologic evaluation. Results: Oxygenation results were similar in all groups; however, the groups were lined as follows according to the increasing severity of morphometric evaluation parameters: Group 15-0: (0±0.009) < Group 30-10: (0±0.14) < Group 30-5&RM: (1±0.12) < Group 30-5: (1±0.16) < Group 45-0: (2±0.16). Besides, inflammatory responses were the lowest in 30-5&RM group compared to all other groups. TNF-α, IL-1β, IL-6, MCP-1 levels were significantly different between group 30-5&RM and group 15-0 vs. group 45-0 in each group. Conclusion: RM with low PEEP reduces the risk of ventilator-induced lung injury with a lower release of systemic inflammatory mediators in response to mechanical ventilation. PMID:25207105

  10. Do We Deliver the Pressures We Intend to When Using a T-Piece Resuscitator?

    PubMed Central

    Walther, Frans J.; Roehr, Charles C.; te Pas, Arjan B.

    2013-01-01

    Background A T-piece resuscitator (TPR) uses a built-in manometer to set the inflation pressures, but we are not informed what pressures are actually delivered distally. Aim of this study was to measure the proximal and distal pressures under different gas conditions when using a TPR. Methodology/Findings A test lung was ventilated using a TPR (PIP 25 cmH2O, PEEP 5 cmH2O) with a gas flow rate of 8 L/min. A) Pressure delivered by six different TPRs was tested. To test variability 20 participants were asked to set PEEP and PIP pressures to 25/5 cmH2O. B) PIP and PEEP were measured proximal and distal of the TPR when using standard tubing or heated tubing with or without a humidifier. In experiment A mean (SD) proximal PIP and PEEP of the TPRs were respectively 20.3 (0.3) cmH2O (19.9–20.6 cmH2O) and 4.9 (0.1) cmH2O. When 20 participants set pressures; PIP 26.7 (0.5) cm H2O and PEEP 5.9 (0.44) cmH2O were measured. Experiment B showed that the decrease of PIP between proximal and distal pressures was not clinically significant. However there was a significant decrease of PEEP using the standard tubing (5.1 (0.1) cmH2O proximally versus 4.8 (0.2) cmH2O distally; p<0.001) compared to, when using a humidifier with associated tubing and the humidifier turned on, 5.1 (0.1) proximally versus 3.9 (0.2) cmH2O distally; (p<0.001). Conclusion/Significance The accuracy of the built-in manometer of a TPR is acceptable. Most pressures set proximally are comparable to the actual pressures delivered distally. However, when using tubing associated with the humidifier PEEP decreases distally by 1.1–1.2 cmH2O and users should anticipate on this. PMID:23717652

  11. Respiratory and haemodynamic changes during decremental open lung positive end-expiratory pressure titration in patients with acute respiratory distress syndrome

    PubMed Central

    Gernoth, Christian; Wagner, Gerhard; Pelosi, Paolo; Luecke, Thomas

    2009-01-01

    Introduction To investigate haemodynamic and respiratory changes during lung recruitment and decremental positive end-expiratory pressure (PEEP) titration for open lung ventilation in patients with acute respiratory distress syndrome (ARDS) a prospective, clinical trial was performed involving 12 adult patients with ARDS treated in the surgical intensive care unit in a university hospital. Methods A software programme (Open Lung Tool™) incorporated into a standard ventilator controlled the recruitment (pressure-controlled ventilation with fixed PEEP at 20 cmH2O and increased driving pressures at 20, 25 and 30 cmH2O for two minutes each) and PEEP titration (PEEP lowered by 2 cmH2O every two minutes, with tidal volume set at 6 ml/kg). The open lung PEEP (OL-PEEP) was defined as the PEEP level yielding maximum dynamic respiratory compliance plus 2 cmH2O. Gas exchange, respiratory mechanics and central haemodynamics using the Pulse Contour Cardiac Output Monitor (PiCCO™), as well as transoesophageal echocardiography were measured at the following steps: at baseline (T0); during the final recruitment step with PEEP at 20 cmH2O and driving pressure at 30 cmH2O, (T20/30); at OL-PEEP, following another recruitment manoeuvre (TOLP). Results The ratio of partial pressure of arterial oxygen (PaO2) to fraction of inspired oxygen (FiO2) increased from T0 to TOLP (120 ± 59 versus 146 ± 64 mmHg, P < 0.005), as did dynamic respiratory compliance (23 ± 5 versus 27 ± 6 ml/cmH2O, P < 0.005). At constant PEEP (14 ± 3 cmH2O) and tidal volumes, peak inspiratory pressure decreased (32 ± 3 versus 29 ± 3 cmH2O, P < 0.005), although partial pressure of arterial carbon dioxide (PaCO2) was unchanged (58 ± 22 versus 53 ± 18 mmHg). No significant decrease in mean arterial pressure, stroke volume or cardiac output occurred during the recruitment (T20/30). However, left ventricular end-diastolic area decreased at T20/30 due to a decrease in the left ventricular end-diastolic septal

  12. Effect of tidal volume and positive end-expiratory pressure on expiratory time constants in experimental lung injury.

    PubMed

    Henderson, William R; Dominelli, Paolo B; Molgat-Seon, Yannick; Lipson, Rachel; Griesdale, Donald E G; Sekhon, Mypinder; Ayas, Najib; Sheel, A William

    2016-03-01

    We utilized a multicompartment model to describe the effects of changes in tidal volume (VT) and positive end-expiratory pressure (PEEP) on lung emptying during passive deflation before and after experimental lung injury. Expiratory time constants (τE) were determined by partitioning the expiratory flow-volume (V˙EV) curve into multiple discrete segments and individually calculating τE for each segment. Under all conditions of PEEP and VT, τE increased throughout expiration both before and after injury. Segmented τE values increased throughout expiration with a slope that was different than zero (P < 0. 01). On average, τE increased by 45.08 msec per segment. When an interaction between injury status and τE segment was included in the model, it was significant (P < 0.05), indicating that later segments had higher τE values post injury than early τE segments. Higher PEEP and VT values were associated with higher τE values. No evidence was found for an interaction between injury status and VT, or PEEP. The current experiment confirms previous observations that τE values are smaller in subjects with injured lungs when compared to controls. We are the first to demonstrate changes in the pattern of τE before and after injury when examined with a multiple compartment model. Finally, increases in PEEP or VT increased τE throughout expiration, but did not appear to have effects that differed between the uninjured and injured state. PMID:26997633

  13. Pros and cons of recruitment maneuvers in acute lung injury and acute respiratory distress syndrome.

    PubMed

    Rocco, Patricia R M; Pelosi, Paolo; de Abreu, Marcelo Gama

    2010-08-01

    In patients with acute lung injury and acute respiratory distress syndrome, a protective mechanical ventilation strategy characterized by low tidal volumes has been associated with reduced mortality. However, such a strategy may result in alveolar collapse, leading to cyclic opening and closing of atelectatic alveoli and distal airways. Thus, recruitment maneuvers (RMs) have been used to open up collapsed lungs, while adequate positive end-expiratory pressure (PEEP) levels may counteract alveolar derecruitment during low tidal volume ventilation, improving respiratory function and minimizing ventilator-associated lung injury. Nevertheless, considerable uncertainty remains regarding the appropriateness of RMs. The most commonly used RM is conventional sustained inflation, associated with respiratory and cardiovascular side effects, which may be minimized by newly proposed strategies: prolonged or incremental PEEP elevation; pressure-controlled ventilation with fixed PEEP and increased driving pressure; pressure-controlled ventilation applied with escalating PEEP and constant driving pressure; and long and slow increase in pressure. The efficiency of RMs may be affected by different factors, including the nature and extent of lung injury, capability of increasing inspiratory transpulmonary pressures, patient positioning and cardiac preload. Current evidence suggests that RMs can be used before setting PEEP, after ventilator circuit disconnection or as a rescue maneuver to overcome severe hypoxemia; however, their routine use does not seem to be justified at present. The development of new lung recruitment strategies that have fewer hemodynamic and biological effects on the lungs, as well as randomized clinical trials analyzing the impact of RMs on morbidity and mortality of acute lung injury/acute respiratory distress syndrome patients, are warranted. PMID:20658909

  14. Assessment of Lung Recruitment by Electrical Impedance Tomography and Oxygenation in ARDS Patients

    PubMed Central

    Yun, Long; He, Huai-wu; Möller, Knut; Frerichs, Inéz; Liu, Dawei; Zhao, Zhanqi

    2016-01-01

    Abstract We hypothesized that not all patients with appreciably recruited lung tissue during a recruitment maneuver (RM) show significant improvement of oxygenation. In the present study, we combined electrical impedance tomography (EIT) with oxygenation measurements to examine the discrepancies of lung ventilation and perfusion versus oxygenation after RM. A 2-minute RM (20 cm H2O positive end-expiratory pressure [PEEP] + 20 cm H2O pressure control) was prospectively conducted in 20 acute respiratory distress syndrome patients from January 2014 to December 2014. A decremental PEEP trial was performed to select the PEEP level after RM. A positive response to RM was identified as PaO2 + PaCO2 ≥400 mm Hg. Relative differences in the distribution of ventilation and perfusion in the most dependent region of interest (ROI4) were monitored with EIT and denoted as the ventilation-perfusion index. Ten patients were found to be responders and 10 patients to be nonresponders. No significant difference in baseline PaO2/FiO2 was observed between nonresponders and responders. A significantly higher PaO2/FiO2 ratio during RM and higher PEEP set after PEEP titration were recorded in responders. In both responders and nonresponders, the proportion of ventilation distributed in ROI4 compared with the global value was lower than the cardiac-related activity before RM, but this situation was reversed after RM (P < 0.01 in each group). Six out of 10 nonresponders exhibited a remarkable increase in ventilation in ROI4. A significant difference in the relative ventilation-perfusion index was found between the patients with remarkable and insufficient lung tissue reopening in the nonresponder group (P < 0.01). A discrepancy between lung tissue reopening and oxygenation improvement after RM was observed. EIT has the potential to evaluate the efficacy of RM by combining oxygenation measurements. PMID:27258527

  15. Dose-response comparisons of five lung surfactant factor (LSF) preparations in an animal model of adult respiratory distress syndrome (ARDS).

    PubMed Central

    Häfner, D.; Beume, R.; Kilian, U.; Krasznai, G.; Lachmann, B.

    1995-01-01

    1. We have examined the effects of five different lung surfactant factor (LSF) preparations in the rat lung lavage model. In this model repetitive lung lavage leads to lung injury with some similarities to adult respiratory distress syndrome with poor gas exchange and protein leakage into the alveolar spaces. These pathological sequelae can be reversed by LSF instillation soon after lavage. 2. The tested LSF preparations were: two bovine: Survanta and Alveofact: two synthetic: Exosurf and a protein-free phospholipid based LSF (PL-LSF) and one Recombinant LSF at doses of 25, 50 and 100 mg kg-1 body weight and an untreated control group. 3. Tracheotomized rats (10-12 per dose) were pressure-controlled ventilated (Siemens Servo Ventilator 900C) with 100% oxygen at a respiratory rate of 30 breaths min-1, inspiration expiration ratio of 1:2, peak inspiratory pressure (PIP) of 28 cmH2O at positive end-expiratory pressure (PEEP) of 8 cmH2O. Two hours after LSF administration, PEEP and in parallel PIP was reduced from 8 to 6 (1st reduction), from 6 to 3 (2nd reduction) and from 3 to 0 cmH2O (3rd reduction). 4. Partial arterial oxygen pressure (PaO2, mmHg) at 5 min and 120 min after LSF administration and during the 2nd PEEP reduction (PaO2(PEEP23/3)) were used for statistical comparison. All LSF preparations caused a dose-dependent increase for the PaO2(120'), whereas during the 2nd PEEP reduction only bovine and recombinant LSF exhibited dose-dependency. Exosurf did not increase PaO2 after administration of the highest dose. At the highest dose Exosurf exerted no further improvement but rather a tendency to relapse.(ABSTRACT TRUNCATED AT 250 WORDS) Images Figure 2 Figure 3 Figure 4 PMID:7582456

  16. [Effect of changes in airway pressure and the inspiratory volume on the fluid filtration rate and pulmonary artery pressure in isolated rabbit lungs perfused with blood and acellular solution].

    PubMed

    Crespo, Astrid; Novoa, Eva; Urich, Daniela; Trejo, Humberto; Pezzulo, Alejandro; Sznajder, Jacob I; Livia, Fernández; Sánchez-de León, Roberto

    2006-12-01

    It has been reported that ventilation with large tidal volumes causes pulmonary edema in rats by the stimulation and release of proinflammatory mediators. Our objective was to determine the level at which volutrauma induced by changes in Airway Pressure (PAW) and Inspiratory Volume (VI) produce significant changes on the Fluid Filtration Rate (FFR) and Pulmonary Artery Pressure (PAP) in lungs perfused with blood (cellular groups) or with a buffer-albumin solution (acellular groups), with a Positive End Expiratory Pressure (PEEP) 0 or 2 cmH2O and to study the effect of a vasodilator with antiinflammatory properties (fenoterol) in blood-perfused groups. Three experimental groups were used: the cellular groups studied the effect of increased PAW and IV in isolated lungs perfused with blood and PEEP 0 and 2; the acellular groups studied the increased PAW and IV in isolated lungs perfused with a buffer-albumin solution and PEEP 0 and 2; The fenoterol group studied the effect of increased PAW and IV in isolated lungs perfused with blood + fenoterol and PEEP 2. The results show that an increase of FFR is produced earlier in acellular groups than in cellular ones and that the damage in cellular groups is microscopically and macroscopically inferior when compared to acellular groups. Fenoterol did not inhibit edema formation, and that PEEP 2, both in the cellular and the acellular groups, has a protective effect. We propose the possible existence of mediators with protective effects against the formation of pulmonary edema in the blood. These data suggest that volutrauma induced pulmonary edema has a predominantly traumatic origin when the lungs are perfused with blood. PMID:17176901

  17. Assessment of Lung Recruitment by Electrical Impedance Tomography and Oxygenation in ARDS Patients.

    PubMed

    Yun, Long; He, Huai-Wu; Möller, Knut; Frerichs, Inéz; Liu, Dawei; Zhao, Zhanqi

    2016-05-01

    We hypothesized that not all patients with appreciably recruited lung tissue during a recruitment maneuver (RM) show significant improvement of oxygenation. In the present study, we combined electrical impedance tomography (EIT) with oxygenation measurements to examine the discrepancies of lung ventilation and perfusion versus oxygenation after RM.A 2-minute RM (20 cm H2O positive end-expiratory pressure [PEEP] + 20 cm H2O pressure control) was prospectively conducted in 20 acute respiratory distress syndrome patients from January 2014 to December 2014. A decremental PEEP trial was performed to select the PEEP level after RM. A positive response to RM was identified as PaO2 + PaCO2 ≥400 mm Hg. Relative differences in the distribution of ventilation and perfusion in the most dependent region of interest (ROI4) were monitored with EIT and denoted as the ventilation-perfusion index.Ten patients were found to be responders and 10 patients to be nonresponders. No significant difference in baseline PaO2/FiO2 was observed between nonresponders and responders. A significantly higher PaO2/FiO2 ratio during RM and higher PEEP set after PEEP titration were recorded in responders. In both responders and nonresponders, the proportion of ventilation distributed in ROI4 compared with the global value was lower than the cardiac-related activity before RM, but this situation was reversed after RM (P < 0.01 in each group). Six out of 10 nonresponders exhibited a remarkable increase in ventilation in ROI4. A significant difference in the relative ventilation-perfusion index was found between the patients with remarkable and insufficient lung tissue reopening in the nonresponder group (P < 0.01).A discrepancy between lung tissue reopening and oxygenation improvement after RM was observed. EIT has the potential to evaluate the efficacy of RM by combining oxygenation measurements. PMID:27258527

  18. Respiratory failure in patients with acquired immunodeficiency syndrome and Pneumocystis carinii pneumonia.

    PubMed

    Maxfield, R A; Sorkin, I B; Fazzini, E P; Rapoport, D M; Stenson, W M; Goldring, R M

    1986-05-01

    Seven patients with acquired immunodeficiency syndrome (AIDS) and Pneumocystis carinii pneumonia were studied to define the pathophysiology of their respiratory failure. The patients had fever, cough, dyspnea, hypoxemia, and diffuse infiltrates on chest x-ray. Biopsies revealed a spectrum of alveolar filling, interstitial edema and infiltration, and fibrosis. The patients were studied on mechanical ventilation to assess the effect of positive end-expiratory pressure (PEEP) and supplemental oxygen on shunt fraction. Mean anatomic shunt (measured on 100% oxygen) was 34 +/- 8%, which increased significantly (p less than .001) to 43 +/- 9% when the FIO2 was decreased to 40% to 60% (physiologic shunt), indicating ventilation/perfusion (V/Q) imbalance or impaired diffusion. Increasing PEEP by 9 +/- 2 cm H2O reduced the anatomic shunt to 30 +/- 7% (p less than .01) and the physiologic shunt to 37 +/- 7% (p less than .02). There was a similar decrease in anatomic and physiologic shunts in five studies, a greater decrease in physiologic shunt in four, and a greater decrease in anatomic shunt in two. Evidence of alveolar recruitment with PEEP, measured by an increase in static thoracic compliance, was found in only one study. There was no correlation between the effect of PEEP on compliance and its effect on shunt. The data suggest that in patients with AIDS and P. carinii pneumonia, PEEP can decrease shunt by reducing the anatomic shunt, improving V/Q imbalance, and converting areas of anatomic shunt to areas of low V/Q. P. carinii pneumonia in patients with AIDS can produce a clinical and pathophysiologic pattern similar to that described in the adult respiratory distress syndrome. PMID:3516574

  19. Application of a Novel Automatic Erosion and Deposition Monitoring System at a Channel Bank Site on the Tidal River Trent, U.K.

    NASA Astrophysics Data System (ADS)

    Lawler, D. M.; West, J. R.; Couperthwaite, J. S.; Mitchell, S. B.

    2001-08-01

    There is a well-defined need to improve understanding of the dynamics of sediment erosion and deposition on intertidal channel banks, given their importance to channel stability, sediment budgets, depth maintenance, pollutant and nutrient transport, and ecological processes in estuarine systems. Conventional, manual methods for field monitoring of erosion and deposition, however, normally deliver information of low temporal resolution conditioned by infrequent field resurveys. To address this problem, this paper discusses a recently developed and improved automatic erosion and deposition monitoring technique, the Photo-Electronic Erosion Pin (PEEP) system, and its application to a tidal channel bank site at Burringham on the River Trent, U.K. The PEEP system allows the magnitude, frequency and timing of individual erosion and deposition events to be monitored much more precisely than with conventional manual methods. PEEP sensors also monitor light intensity and sediment temperature, variables which can influence bank stabilizing and destabilizing processes. Example results at both the event and spring-neap timescales are presented from a short PEEP system deployment between March and May 1997 at Burringham. These establish that discrete erosion events of >60 mm and 100 mm can occur in response to individual tidal cycles, events which are readily monitored automatically and quasicontinuously by the PEEP system. The capability of the PEEP approach to enhance temporal resolution of monitoring is demonstrated by the determination of the timing of the 100-mm bank erosion incident to an ' event window ' of 2·75 h: this converts to mean bank erosion rate of 36 mm h -1over the period of inundation. In addition, the PEEP system defines the magnitude and date of two example deposition events of 47 and 92 mm on the lower bank during a sequence of rising spring tides. These represent mean deposition rates of 4·5 and 8·4 mm h -1respectively over the periods of inundation

  20. Rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART): Study protocol for a randomized controlled trial

    PubMed Central

    2012-01-01

    Background Acute respiratory distress syndrome (ARDS) is associated with high in-hospital mortality. Alveolar recruitment followed by ventilation at optimal titrated PEEP may reduce ventilator-induced lung injury and improve oxygenation in patients with ARDS, but the effects on mortality and other clinical outcomes remain unknown. This article reports the rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART). Methods/Design ART is a pragmatic, multicenter, randomized (concealed), controlled trial, which aims to determine if maximum stepwise alveolar recruitment associated with PEEP titration is able to increase 28-day survival in patients with ARDS compared to conventional treatment (ARDSNet strategy). We will enroll adult patients with ARDS of less than 72 h duration. The intervention group will receive an alveolar recruitment maneuver, with stepwise increases of PEEP achieving 45 cmH2O and peak pressure of 60 cmH2O, followed by ventilation with optimal PEEP titrated according to the static compliance of the respiratory system. In the control group, mechanical ventilation will follow a conventional protocol (ARDSNet). In both groups, we will use controlled volume mode with low tidal volumes (4 to 6 mL/kg of predicted body weight) and targeting plateau pressure ≤30 cmH2O. The primary outcome is 28-day survival, and the secondary outcomes are: length of ICU stay; length of hospital stay; pneumothorax requiring chest tube during first 7 days; barotrauma during first 7 days; mechanical ventilation-free days from days 1 to 28; ICU, in-hospital, and 6-month survival. ART is an event-guided trial planned to last until 520 events (deaths within 28 days) are observed. These events allow detection of a hazard ratio of 0.75, with 90% power and two-tailed type I error of 5%. All analysis will follow the intention-to-treat principle. Discussion If the ART strategy with maximum recruitment and PEEP titration improves 28-day survival, this

  1. Continuous Non-Invasive Monitoring of Tidal Volumes by Measurement of Tidal Impedance in Neonatal Piglets

    PubMed Central

    Kurth, Florian; Zinnow, Fabienne; Prakapenia, Alexandra; Dietl, Sabrina; Winkler, Stefan; Ifflaender, Sascha; Rüdiger, Mario; Burkhardt, Wolfram

    2011-01-01

    Background Electrical Impedance measurements can be used to estimate the content of intra-thoracic air and thereby give information on pulmonary ventilation. Conventional Impedance measurements mainly indicate relative changes, but no information concerning air-volume is given. The study was performed to test whether a 3-point-calibration with known tidal volumes (VT) during conventional mechanical ventilation (CMV) allows subsequent calculation of VT from total Tidal-Impedance (tTI) measurements using Quadrant Impedance Measurement (QIM). In addition the distribution of TI in different regions of the thorax was examined. Methodology and Principal Findings QIM was performed in five neonatal piglets during volume-controlled CMV. tTI values at three different VT (4, 6, 8 ml/kg) were used to establish individual calibration curves. Subsequently, each animal was ventilated with different patterns of varying VT (2–10 ml/kg) at different PEEP levels (0, 3, 6, 9, 12 cmH2O). VT variation was repeated after surfactant depletion by bronchoalveolar lavage. VT was calculated from tTI values (VTcalc) and compared to the VT delivered by the ventilator (VTPNT). Bland-Altman analysis revealed good agreement between VTcalc and VTPNT before (bias −0.08 ml; limits of agreement −1.18 to 1.02 ml at PEEP = 3 cmH2O) and after surfactant depletion (bias −0.17 ml; limits of agreement −1.57 to 1.22 ml at PEEP = 3 cmH2O). At higher PEEP levels VTcalc was lower than VTPNT, when only one fixed calibration curve (at PEEP 3 cmH2O) was used. With a new calibration curve at each PEEP level the method showed similar accuracy at each PEEP level. TI showed a homogeneous distribution over the four assessed quadrants with a shift toward caudal regions of the thorax with increasing VT. Conclusion Tidal Impedance values could be used for precise and accurate calculation of VT during CMV in this animal study, when calibrated at each PEEP level. PMID:21687746

  2. [Pathophysiology of recruit ventilation and its effect on the respiration biomechanics (review of the literature)].

    PubMed

    Marchenkov, Iu V; Moroz, V V; Izmaĭlov, V V

    2012-01-01

    In patients with acute respiratory distress syndrome (ARDS) lungs consist of aeration zones and zones of alveolar collapse, which lead to intrapulmonary shunting and hypoxemia. ALV may increase alveolar collaps and potentially lead to lung damage arising out of displacing surfaces tension between aerated and collapsed lung parts and re-closing and opening of the alveoli. Based on the strategy of the "open lung" the recruitment maneuver can be used to achieve the alveolar recruitment, while PEEP prevents alveolar collapse. There are many recrutment types, including a long inflated to a higher pressure, reccuring breath, gradual increase of PEEP, and PIP etc. Data on the use of recruitment in ARDS patients, show varied results with increased efficiency in patients with early ARDS, good complaisance of the chest and extrapulmonary Genesis of lung damage. In this review, we discuss the pathophysiological basis of recruitment use, recent evidence and contradictions of the application of this method. PMID:22993921

  3. Common-path Fourier domain optical coherence tomography of irradiated human skin and ventilated isolated rabbit lungs

    NASA Astrophysics Data System (ADS)

    Popp, A.; Wendel, M.; Knels, L.; Knuschke, P.; Mehner, M.; Koch, T.; Boller, D.; Koch, P.; Koch, E.

    2005-08-01

    A compact common path Fourier domain optical coherence tomography (FD-OCT) system based on a broadband superluminescence diode is used for biomedical imaging. The epidermal thickening of human skin after exposure to ultraviolet radiation is measured to proof the feasibility of FD-OCT for future substitution of invasive biopsies in a long term study on natural UV skin protection. The FD-OCT system is also used for imaging lung parenchyma. FD-OCT images of a formalin fixated lung show the same alveolar structure as scanning electron microscopy images. In the ventilated and blood-free perfused isolated rabbit lung FD-OCT is used for real-time cross-sectional image capture of alveolar mechanics throughout tidal ventilation. The alveolar mechanics changing from alternating recruitment-derecruitment at zero positive end-expiratory pressure (PEEP) to persistent recruitment after applying a PEEP of 5 cm H2O is observed in the OCT images.

  4. A New Technique for the Automatic Monitoring of Erosion and Deposition Rates

    NASA Astrophysics Data System (ADS)

    Lawler, D. M.

    1991-08-01

    The rates and processes of erosion and deposition of soils and sediments are subjects of widespread and increasing concern in the Earth and environmental sciences. Process inference from field studies, however, has been hampered by a lack of information on the precise magnitude, frequency and timing of erosional and depositional activity, because no automatic monitoring technique has hitherto been available. I describe here an automatic Photo-Electronic Erosion Pin (PEEP) system which, apparently for the first time, allows quasi-continuous time series of erosion and deposition data to be collected. Example results from a river bank site show how the PEEP system helps to define the true temporal distribution of geomorphological change, quantify the erosional impact of individual forcing events, and discriminate between competing hypotheses of process control in erosional and depositional contexts. The system should thus allow more effective testing of erosion models of high temporal resolution and facilitate a more rigorous linking of catchment sediment output to supply dynamics.

  5. Current concepts of protective ventilation during general anaesthesia.

    PubMed

    Serpa Neto, Ary; Schultz, Marcus J; Slutsky, Arthur S

    2015-01-01

    Mechanical ventilation with high tidal volumes (VT) has been common practice in operating theatres because this strategy recruits collapsed lung tissue and improves ventilation-perfusion mismatch, thus decreasing the need for high inspired oxygen concentrations. Positive end-expiratory pressure (PEEP) was not used routinely because it was thought to impair cardiovascular function. Over the past two decades there have been advances in our understanding of the causes and importance of ventilation-induced lung injury based on studies in animals with healthy lungs, and trials in critically ill patients with and without acute respiratory distress syndrome. Recent data from randomised controlled trials in patients receiving ventilation during general anaesthesia for surgery have demonstrated that lung-protective strategies (use of low VT, use of PEEP if indicated, and avoidance of excessive oxygen concentrations) are also of importance during intraoperative ventilation. PMID:26561993

  6. Nitric oxide synthase promotes distension-induced tracheal venular leukocyte adherence.

    PubMed

    Moldobaeva, Aigul; Rentsendorj, Otgonchimeg; Jenkins, John; Wagner, Elizabeth M

    2014-01-01

    The process of leukocyte recruitment to the airways in real time has not been extensively studied, yet airway inflammation persists as a major contributor to lung pathology. We showed previously in vivo, that neutrophils are recruited acutely to the large airways after periods of airway distension imposed by the application of positive end-expiratory pressure (PEEP). Given extensive literature implicating products of nitric oxide synthase (NOS) in lung injury after ventilatory over-distension, we questioned whether similar mechanisms exist in airway post-capillary venules. Yet, endothelial nitric oxide has been shown to be largely anti-inflammatory in other systemic venules. Using intravital microscopy to visualize post-capillary tracheal venules in anesthetized, ventilated mice, the number of adherent leukocytes was significantly decreased in eNOS-/- mice under baseline conditions (2±1 cell/60 min observation) vs wild type (WT) C57BL/6 mice (7±2 cells). After exposure to PEEP (8 cmH2O for 1 min; 5 times), adherent cells increased significantly (29±5 cells) in WT mice while eNOS-/- mice demonstrated a significantly decreased number of adherent cells (11±4 cells) after PEEP. A similar response was seen when thrombin was used as the pro-inflammatory stimulus. In addition, mouse tracheal venular endothelial cells studied in vitro after exposure to cyclic stretch (18% elongation) or thrombin both demonstrated increased p-selectin expression that was significantly attenuated by NG-nitro-L-arginine methyl ester, N-acetylcysteine amide (NACA) and excess BH4. In vivo treatment with the ROS inhibitor NACA or co-factor BH4 abolished completely the PEEP-induced leukocyte adherence. These results suggest that pro-inflammatory stimuli cause leukocyte recruitment to tracheal endothelium in part due to eNOS uncoupling. PMID:25181540

  7. Nitric Oxide Synthase Promotes Distension-Induced Tracheal Venular Leukocyte Adherence

    PubMed Central

    Moldobaeva, Aigul; Rentsendorj, Otgonchimeg; Jenkins, John; Wagner, Elizabeth M.

    2014-01-01

    The process of leukocyte recruitment to the airways in real time has not been extensively studied, yet airway inflammation persists as a major contributor to lung pathology. We showed previously in vivo, that neutrophils are recruited acutely to the large airways after periods of airway distension imposed by the application of positive end-expiratory pressure (PEEP). Given extensive literature implicating products of nitric oxide synthase (NOS) in lung injury after ventilatory over-distension, we questioned whether similar mechanisms exist in airway post-capillary venules. Yet, endothelial nitric oxide has been shown to be largely anti-inflammatory in other systemic venules. Using intravital microscopy to visualize post-capillary tracheal venules in anesthetized, ventilated mice, the number of adherent leukocytes was significantly decreased in eNOS-/- mice under baseline conditions (2±1 cell/60 min observation) vs wild type (WT) C57BL/6 mice (7±2 cells). After exposure to PEEP (8 cmH2O for 1 min; 5 times), adherent cells increased significantly (29±5 cells) in WT mice while eNOS-/- mice demonstrated a significantly decreased number of adherent cells (11±4 cells) after PEEP. A similar response was seen when thrombin was used as the pro-inflammatory stimulus. In addition, mouse tracheal venular endothelial cells studied in vitro after exposure to cyclic stretch (18% elongation) or thrombin both demonstrated increased p-selectin expression that was significantly attenuated by NG-nitro-L-arginine methyl ester, N-acetylcysteine amide (NACA) and excess BH4. In vivo treatment with the ROS inhibitor NACA or co-factor BH4 abolished completely the PEEP-induced leukocyte adherence. These results suggest that pro-inflammatory stimuli cause leukocyte recruitment to tracheal endothelium in part due to eNOS uncoupling. PMID:25181540

  8. Ventilator-driven xenon ventilation studies

    SciTech Connect

    Chilcoat, R.T.; Thomas, F.D.; Gerson, J.I.

    1984-07-01

    A modification of a common commercial Xe-133 ventilation device is described for mechanically assisted ventilation imaging. The patient's standard ventilator serves as the power source controlling the ventilatory rate and volume during the xenon study, but the gases in the two systems are not intermixed. This avoids contamination of the ventilator with radioactive xenon. Supplemental oxygen and positive end-expiratory pressure (PEEP) are provided if needed. The system can be converted quickly for conventional studies with spontaneous respiration.

  9. Giving Reluctant Students a Voice

    ERIC Educational Resources Information Center

    Redekopp, Reynold; Bourbonniere, Elizabeth

    2009-01-01

    All teachers know them--the students who sit in the back of the room and never make a peep. If prodded, they may reluctantly offer a comment or opinion, but they are so obviously uncomfortable about participating that a teacher may wonder if it is even worth trying to engage them. Are they unprepared or just shy? Do they lack ideas or merely need…

  10. Ventilator-driven xenon ventilation studies

    SciTech Connect

    Chilcoat, R.T.; Thomas, F.D.; Gerson, J.I.

    1984-07-01

    A modification of a common commerical Xe-133 ventilation device is described for mechanically assisted ventilation imaging. The patient's standard ventilator serves as the power source controlling the ventilator rate and volume during the xenon study, but the gases in the two systems are not intermixed. This avoids contamination of the ventilator with radioactive xenon. Supplemental oxygen and positive end-expiratory pressure (PEEP) are provided if needed. The system can be converted quickly for conventional studies with spontaneous respiration.

  11. Apparent diffusion coefficient of hyperpolarized (3)He with minimal influence of the residual gas in small animals.

    PubMed

    Carrero-González, L; Kaulisch, T; Ruiz-Cabello, J; Pérez-Sánchez, J M; Peces-Barba, G; Stiller, D; Rodríguez, I

    2012-09-01

    The apparent diffusion coefficient (ADC) of hyperpolarized (HP) gases is a parameter that reflects changes in lung microstructure. However, ADC is dependent on many physiological and experimental variables that need to be controlled or specified in order to ensure the reliability and reproducibility of this parameter. A single breath-hold experiment is desirable in order to reduce the amount of consumed HP gas. The application of a positive end-expiratory pressure (PEEP) causes an increase in the residual gas volume. Depending on the applied PEEP, the ratio between the incoming and residual gas volumes will change and the ADC will vary, as long as both gases do not have the same diffusion coefficient. The most standard method for human applications uses air for breathing and a bolus of pure HP (3)He for MRI data acquisition. By applying this method in rats, we have demonstrated that ADC values are strongly dependent on the applied PEEP, and therefore on the residual gas volume in the lung. This outcome will play an important role in studies concerning certain diseases, such as emphysema, which is characterized by an increase in the residual volume. Ventilation with an oxygen-helium mixture (VOHeM) is a proposed single breath-hold method that uses two different gas mixtures (O(2)-(4)He for ventilation and HP (3)He-N(2) for imaging). The concentration of each gas in its respective mixture was calculated in order to obtain the same diffusion coefficient in both mixtures. ADCs obtained from VOHeM are independent of PEEP, thus minimizing the effect of the different residual volumes. PMID:22275333

  12. Imaging of the three-dimensional alveolar structure and the alveolar mechanics of a ventilated and perfused isolated rabbit lung with Fourier domain optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Popp, Alexander; Wendel, Martina; Knels, Lilla; Koch, T.; Koch, Edmund

    2006-01-01

    In this feasibility study, Fourier domain optical coherence tomography (FDOCT) is used for visualizing the 3-D structure of fixated lung parenchyma and to capture real-time cross sectional images of the subpleural alveolar mechanics in a ventilated and perfused isolated rabbit lung. The compact and modular setup of the FDOCT system allows us to image the first 500 µm of subpleural lung parenchyma with a 3-D resolution of 16×16×8 µm (in air). During mechanical ventilation, real-time cross sectional FDOCT images visualize the inflation and deflation of alveoli and alveolar sacks (acini) in successive images of end-inspiratory and end-expiratory phase. The FDOCT imaging shows the relation of local alveolar mechanics to the setting of tidal volume (VT), peak airway pressure, and positive end-expiratory pressure (PEEP). Application of PEEP leads to persistent recruitment of alveoli and acini in the end-expiratory phase, compared to ventilation without PEEP where alveolar collapse and reinflation are observed. The imaging of alveolar mechanics by FDOCT will help to determine the amount of mechanical stress put on the alveolar walls during tidal ventilation, which is a key factor in understanding the development of ventilator induced lung injury (VILI).

  13. Effective Ventilation Strategies for Obese Patients Undergoing Bariatric Surgery: A Literature Review.

    PubMed

    Hu, Xin Yan

    2016-02-01

    Obesity causes major alterations in pulmonary mechanics. Obese patients undergoing bariatric surgery present mechanical ventilation-related challenges that may lead to perioperative complications. Databases were systematically searched for clinical trials of ventilation maneuvers for obese patients and bariatric surgery. Thirteen randomized controlled trials were selected. The quality of the studies was evaluated with the Critical Appraisal Skills Programme tool, and a matrix was developed to present the essential components of the studies. Eight strategies of ventilation maneuvers were identified. Recruitment maneuvers followed by positive end-expiratory pressure (PEEP) consistently demonstrated effectiveness in obese patients undergoing bariatric surgery. Pressure-controlled ventilation and volume-controlled ventilation did not differ significantly in their efficacy. Noninvasive positive pressure ventilation (NIPPV) during induction was effective in preventing atelectasis and increasing the duration of safe apnea. Equal ratio ventilation can be a useful ventilation strategy. Recruitment maneuvers followed by PEEP are effective ventilation strategies for obese patients undergoing bariatric surgery. During induction, NIPPV provides further benefit. Future studies are needed to examine the postoperative effects of recruitment maneuvers with PEEP as well as the efficacy and safety of equal ratio ventilation. PMID:26939387

  14. Respirator triggering of electron beam computed tomography (EBCT): evaluation of dynamic changes during mechanical expiration in the traumatized patient

    NASA Astrophysics Data System (ADS)

    Recheis, Wolfgang A.; Kleinsasser, Axel; Hatschenberger, Robert; Knapp, Rudolf; zur Nedden, Dieter; Hoermann, Christoph

    1999-05-01

    The purpose of this project is to evaluate the dynamic changes during expiration at different levels of positive end- expiratory pressure (PEEP) in the ventilated patient. We wanted to discriminate between normal lung function and acute respiratory distress syndrome (ARDS). After approval by the local Ethic Committee we studied two ventilated patients: (1) with normal lung function; (2) ARDS). We used the 50 ms scan mode of the EBCT. The beam was positioned 1 cm above the diaphragm. The table position remained unchanged. An electronic trigger was developed, that utilizes the respirators synchronizing signal to start the EBCT at the onset of expiration. During controlled mechanical expiration at two levels of PEEP (0 and 15 cm H2O), pulmonary aeration was rated as: well-aerated (-900HU/-500HU), poorly- aerated (-500HU/-100HU) and non-aerated (-100HU/+100HU). Pathological and normal lung function showed different dynamic changes (FIG.4-12). The different PEEP levels resulted in a significant change of pulmonary aeration in the same patient. Although we studied only a very limited number of patients, respirator triggered EBCT may be accurate in discriminating pathological changes due to the abnormal lung function in the mechanically ventilated patient.

  15. Design and Construction of a Microcontroller-Based Ventilator Synchronized with Pulse Oximeter.

    PubMed

    Gölcük, Adem; Işık, Hakan; Güler, İnan

    2016-07-01

    This study aims to introduce a novel device with which mechanical ventilator and pulse oximeter work in synchronization. Serial communication technique was used to enable communication between the pulse oximeter and the ventilator. The SpO2 value and the pulse rate read on the pulse oximeter were transmitted to the mechanical ventilator through transmitter (Tx) and receiver (Rx) lines. The fuzzy-logic-based software developed for the mechanical ventilator interprets these values and calculates the percentage of oxygen (FiO2) and Positive End-Expiratory Pressure (PEEP) to be delivered to the patient. The fuzzy-logic-based software was developed to check the changing medical states of patients and to produce new results (FiO2 ve PEEP) according to each new state. FiO2 and PEEP values delivered from the ventilator to the patient can be calculated in this way without requiring any arterial blood gas analysis. Our experiments and the feedbacks from physicians show that this device makes it possible to obtain more successful results when compared to the current practices. PMID:27289463

  16. High tidal volume ventilation in infant mice.

    PubMed

    Cannizzaro, Vincenzo; Zosky, Graeme R; Hantos, Zoltán; Turner, Debra J; Sly, Peter D

    2008-06-30

    Infant mice were ventilated with either high tidal volume (V(T)) with zero end-expiratory pressure (HVZ), high V(T) with positive end-expiratory pressure (PEEP) (HVP), or low V(T) with PEEP. Thoracic gas volume (TGV) was determined plethysmographically and low-frequency forced oscillations were used to measure the input impedance of the respiratory system. Inflammatory cells, total protein, and cytokines in bronchoalveolar lavage fluid (BALF) and interleukin-6 (IL-6) in serum were measured as markers of pulmonary and systemic inflammatory response, respectively. Coefficients of tissue damping and tissue elastance increased in all ventilated mice, with the largest rise seen in the HVZ group where TGV rapidly decreased. BALF protein levels increased in the HVP group, whereas serum IL-6 rose in the HVZ group. PEEP keeps the lungs open, but provides high volumes to the entire lungs and induces lung injury. Compared to studies in adult and non-neonatal rodents, infant mice demonstrate a different response to similar ventilation strategies underscoring the need for age-specific animal models. PMID:18515194

  17. [Ventilation strategies in the child with severe hypoxemic respiratory failure].

    PubMed

    Donoso F, Alejandro; Arriagada S, Daniela; Díaz R, Franco; Cruces R, Pablo

    2015-01-01

    In this review, we assemble the fundamental concepts of the use of mechanical ventilation (MV) in children with acute respiratory failure (ARDS) and refractory hypoxemia. We also discusses topics of protective ventilation and recruitment potential, and specifically examine the options of ventilation and/or maneuvers designed to optimize the non-aerated lung tissue: alveolar recruitment maneuvers, positive end-expiratory pressure (PEEP) titulation, high frequency oscillatory ventilation (HFOV), airway pressure release ventilation (APRV), aimed at correcting the mismatch ventilation/perfusion (V/Q): use of prone position. The only pharmacological intervention analyzed is the use of neuromuscular blockers. In clinical practice, the protective MV concept involves using an individual adjustment of the PEEP and volume tidal (V(T)). Use of recruitment maneuvers and PEEP downward titration can improve lung function in patients with ARDS and severe hypoxemia. We must keep in mind HFOV instauration as early as possible in response to failure of MV. The use of early and prolonged prone can improve gas exchange in hopes of a better control of what caused the use of MV. PMID:25739487

  18. Imaging of the three-dimensional alveolar structure and the alveolar mechanics of a ventilated and perfused isolated rabbit lung with Fourier domain optical coherence tomography.

    PubMed

    Popp, Alexander; Wendel, Martina; Knels, Lilla; Koch, Thea; Koch, Edmund

    2006-01-01

    In this feasibility study, Fourier domain optical coherence tomography (FDOCT) is used for visualizing the 3-D structure of fixated lung parenchyma and to capture real-time cross sectional images of the subpleural alveolar mechanics in a ventilated and perfused isolated rabbit lung. The compact and modular setup of the FDOCT system allows us to image the first 500 microm of subpleural lung parenchyma with a 3-D resolution of 16 x 16 x 8 microm (in air). During mechanical ventilation, real-time cross sectional FDOCT images visualize the inflation and deflation of alveoli and alveolar sacks (acini) in successive images of end-inspiratory and end-expiratory phase. The FDOCT imaging shows the relation of local alveolar mechanics to the setting of tidal volume (VT), peak airway pressure, and positive end-expiratory pressure (PEEP). Application of PEEP leads to persistent recruitment of alveoli and acini in the end-expiratory phase, compared to ventilation without PEEP where alveolar collapse and reinflation are observed. The imaging of alveolar mechanics by FDOCT will help to determine the amount of mechanical stress put on the alveolar walls during tidal ventilation, which is a key factor in understanding the development of ventilator induced lung injury (VILI). PMID:16526892

  19. Changes of air-tissue ratio evaluated by EBCT after cardiopulmonary resuscitation (CPR): validation in swine

    NASA Astrophysics Data System (ADS)

    Recheis, Wolfgang A.; Schuster, Antonius H.; Kleinsasser, Axel; Loeckinger, Alexander; Hoermann, Christoph; zur Nedden, Dieter

    2001-05-01

    The purpose was to evaluate changes of the air-tissue ratio (ATR) in previously defined regions of interest after cardiopulmonary resuscitation (CPR) in porcine model. Eight anesthetized and ventilated pigs we scanned in supine position before and 30 minutes after CPR at two different constant PEEP levels (5 cm H2O, 15 cm H2O). Volume scans were obtained using 6 mm slices. The gray values of the lung were divided into steps of 100 HU in order to get access to the changes of ATR. ATR was evaluated in ventral, intermediate and dorsal regions of the lung. CPR for 9 minutes led to an uneven distribution of ventilation. In the ventral region, areas with high ATR increased. Areas with normal ATR decreased. In contrast the dorsal regions with low ATR increased. ATR in the intermediate regions remained almost unchanged. Using the higher PEEP level, areas with normal ATR showed a marked increase accompanied by a decrease of areas with low ATR. After CPR, an uneven distribution of lung aeration was detected. According to the impaired hemodynamics, areas with normal ATR decreased and areas with high and low ATR increased. Using higher PEEP levels improved lung aeration.

  20. Dynamics of erosion and deposition events on an intertidal mudbank at Burringham, River Trent, UK

    NASA Astrophysics Data System (ADS)

    Mitchell, S. B.; Couperthwaite, J. S.; West, J. R.; Lawler, D. M.

    1999-05-01

    Measurements using an automatic bank level monitoring technique [the photoelectronic erosion pin (PEEP) system] over a 70-day period between 16 March and 27 May 1997 have revealed a complex pattern of erosion and deposition on an intertidal mudbank on the River Trent at Burringham. Comparison of mean daily changes in bank elevation at upper and lower bank positions suggest that wave activity induced by high wind speeds causes erosion, while high tidal range leads to deposition as a result of higher suspended solids concentrations. A greater variability in mean daily erosion and deposition events at the lower bank compared with the upper bank appears to indicate that higher bed shear stresses, as well as a greater availability of sediment for settling, owing to higher concentrations and a greater depth of water, lead to a more dynamic exchange of material at this position. The PEEP data also show longer term trends in sedimentation, with the mean deposition for the period exceeding mean erosion. Manual erosion pin measurements at a lower frequency over a longer, seven-month period confirm this, and also highlight the advantage of the PEEP system in monitoring events at a finer temporal resolution.

  1. Site of deposition and factors affecting clearance of aerosolized solute from canine lungs

    SciTech Connect

    Rizk, N.W.; Luce, J.M.; Hoeffel, J.M.; Price, D.C.; Murray, J.F.

    1984-01-01

    The influence of several factors on lung solute clearance using aerosolized /sup 99m/Tc-diethylenetriaminepentaacetate was determined. The authors used a jet nebulizer-plate separator-balloon system to generate particles with an activity median aerodynamic diameter of 1.1 ..mu..m, administered the aerosol in a standard fashion, and determined clearance half times (t/sub 1/2/) with a gamma-scintillation camera. The following serial studies were performed in five anesthetized, paralyzed, intubated, mechanically ventilated dogs: (1) control, with ventilatory frequency (f) = 15 breaths/min and tidal volume (V/sub T/) = 15 ml/kg during solute clearance; (2) repeat control, for reproducibility; (3) increased frequency, with f = 25 breaths/min and V/sub T/ = 10 ml/kg; (4) positive end-expiratory pressure (PEEP) of 10 cmH/sub 2/O; (5) unilateral pulmonary arterial occlusion (PAO); and (6) bronchial arterial occlusion (BAO). Control t/sub 1/2/ was 25 +/- 5 min and did not change in the repeat control, increased frequency, or BAO experiments. PEEP markedly decreased t/sub 1/2/ to 13 +/- 3 min (P < 0.01), and PAO increased it to 37 +/- 6 min (P < 0.05). We conclude that clearance from the lungs by our method is uninfluenced by increased frequency, increases markedly with PEEP, and depends on pulmonary, not bronchial, blood flow.

  2. The Extent of Ventilator-Induced Lung Injury in Mice Partly Depends on Duration of Mechanical Ventilation

    PubMed Central

    Hegeman, Maria A.; Hemmes, Sabrine N. T.; Kuipers, Maria T.; Bos, Lieuwe D. J.; Jongsma, Geartsje; Roelofs, Joris J. T. H.; van der Sluijs, Koenraad F.; Juffermans, Nicole P.; Vroom, Margreeth B.; Schultz, Marcus J.

    2013-01-01

    Background. Mechanical ventilation (MV) has the potential to initiate ventilator-induced lung injury (VILI). The pathogenesis of VILI has been primarily studied in animal models using more or less injurious ventilator settings. However, we speculate that duration of MV also influences severity and character of VILI. Methods. Sixty-four healthy C57Bl/6 mice were mechanically ventilated for 5 or 12 hours, using lower tidal volumes with positive end-expiratory pressure (PEEP) or higher tidal volumes without PEEP. Fifteen nonventilated mice served as controls. Results. All animals remained hemodynamically stable and survived MV protocols. In both MV groups, PaO2 to FiO2 ratios were lower and alveolar cell counts were higher after 12 hours of MV compared to 5 hours. Alveolar-capillary permeability was increased after 12 hours compared to 5 hours, although differences did not reach statistical significance. Lung levels of inflammatory mediators did not further increase over time. Only in mice ventilated with increased strain, lung compliance declined and wet to dry ratio increased after 12 hours of MV compared to 5 hours. Conclusions. Deleterious effects of MV are partly dependent on its duration. Even lower tidal volumes with PEEP may initiate aspects of VILI after 12 hours of MV. PMID:23691294

  3. The extent of ventilator-induced lung injury in mice partly depends on duration of mechanical ventilation.

    PubMed

    Hegeman, Maria A; Hemmes, Sabrine N T; Kuipers, Maria T; Bos, Lieuwe D J; Jongsma, Geartsje; Roelofs, Joris J T H; van der Sluijs, Koenraad F; Juffermans, Nicole P; Vroom, Margreeth B; Schultz, Marcus J

    2013-01-01

    Background. Mechanical ventilation (MV) has the potential to initiate ventilator-induced lung injury (VILI). The pathogenesis of VILI has been primarily studied in animal models using more or less injurious ventilator settings. However, we speculate that duration of MV also influences severity and character of VILI. Methods. Sixty-four healthy C57Bl/6 mice were mechanically ventilated for 5 or 12 hours, using lower tidal volumes with positive end-expiratory pressure (PEEP) or higher tidal volumes without PEEP. Fifteen nonventilated mice served as controls. Results. All animals remained hemodynamically stable and survived MV protocols. In both MV groups, PaO2 to FiO2 ratios were lower and alveolar cell counts were higher after 12 hours of MV compared to 5 hours. Alveolar-capillary permeability was increased after 12 hours compared to 5 hours, although differences did not reach statistical significance. Lung levels of inflammatory mediators did not further increase over time. Only in mice ventilated with increased strain, lung compliance declined and wet to dry ratio increased after 12 hours of MV compared to 5 hours. Conclusions. Deleterious effects of MV are partly dependent on its duration. Even lower tidal volumes with PEEP may initiate aspects of VILI after 12 hours of MV. PMID:23691294

  4. Functional flexibility in wild bonobo vocal behaviour.

    PubMed

    Clay, Zanna; Archbold, Jahmaira; Zuberbühler, Klaus

    2015-01-01

    A shared principle in the evolution of language and the development of speech is the emergence of functional flexibility, the capacity of vocal signals to express a range of emotional states independently of context and biological function. Functional flexibility has recently been demonstrated in the vocalisations of pre-linguistic human infants, which has been contrasted to the functionally fixed vocal behaviour of non-human primates. Here, we revisited the presumed chasm in functional flexibility between human and non-human primate vocal behaviour, with a study on our closest living primate relatives, the bonobo (Pan paniscus). We found that wild bonobos use a specific call type (the "peep") across a range of contexts that cover the full valence range (positive-neutral-negative) in much of their daily activities, including feeding, travel, rest, aggression, alarm, nesting and grooming. Peeps were produced in functionally flexible ways in some contexts, but not others. Crucially, calls did not vary acoustically between neutral and positive contexts, suggesting that recipients take pragmatic information into account to make inferences about call meaning. In comparison, peeps during negative contexts were acoustically distinct. Our data suggest that the capacity for functional flexibility has evolutionary roots that predate the evolution of human speech. We interpret this evidence as an example of an evolutionary early transition away from fixed vocal signalling towards functional flexibility. PMID:26290789

  5. Lung mechanical changes following bronchoaspiration in a porcine model: differentiation of direct and indirect mechanisms.

    PubMed

    Fodor, Gergely H; Peták, Ferenc; Erces, Dániel; Balogh, Adám L; Babik, Barna

    2014-08-01

    Bronchoaspiration results in local deterioration of lung function through direct damage and/or indirect systemic effects related to neurohumoral pathways. We distinguished these effects by selectively intubating the two main bronchi in pigs while a PEEP of 4 or 10cm H2O was maintained. Gastric juice was instilled only into the right lung. Lung mechanical and ventilation defects were assessed by measuring unilateral pulmonary input impedance (ZL,s) and the third phase slope of the capnogram (SIII) for each lung side separately before the aspiration and for 120min thereafter. Marked transient elevations in ZL,s parameters and SIII were observed in the affected lung after aspiration. Elevating PEEP did not affect these responses in the ZL,s parameters, whereas it prevented the SIII increases. None of these indices changed in the intact left lung. These findings furnish evidence of the predominance of the local direct damage over the indirect systemic effects in the development of the deterioration of lung function, and demonstrate the benefit of an initially elevated PEEP following aspiration. PMID:24814560

  6. Recruitment maneuvers in acute respiratory distress syndrome and during general anesthesia.

    PubMed

    Chiumello, Davide; Algieri, Ilaria; Grasso, Salvatore; Terragni, Pierpaolo; Pelosi, Paolo

    2016-02-01

    The use of low tidal volume ventilation and low to moderate positive end-expiratory pressure (PEEP) levels is a widespread strategy to ventilate patients with non-injured lungs during general anesthesia and in intensive care as well with mild to moderate acute respiratory distress syndrome (ARDS). Higher PEEP levels have been recommended in severe ARDS. Due to the presence of alveolar collapse, recruitment maneuvers (RMs) by causing a transient elevation in airway pressure (i.e. transpulmonary pressure) have been suggested to improve lung inflation in non-inflated and poorly-inflated lung regions. Various types of RMs such as sustained inflation at high pressure, intermittent sighs and stepwise increases of PEEP and/or airway plateau inspiratory pressure have been proposed. The use of RMs has been associated with mixed results in terms of physiological and clinical outcomes. The optimal method for RMs has not yet been identified. The use of RMs is not standardized and left to the individual physician based on his/her experience. Based on the same grounds, RMs have been proposed to improve lung aeration during general anesthesia. The aim of this review was to present the clinical evidence supporting the use of RMs in patients with ARDS and during general anesthesia and as well their potential biological effects in experimental models of acute lung injury. PMID:25881732

  7. Quantitative imaging of alveolar recruitment with hyperpolarized gas MRI during mechanical ventilation.

    PubMed

    Cereda, Maurizio; Emami, Kiarash; Kadlecek, Stephen; Xin, Yi; Mongkolwisetwara, Puttisarn; Profka, Harrilla; Barulic, Amy; Pickup, Stephen; Månsson, Sven; Wollmer, Per; Ishii, Masaru; Deutschman, Clifford S; Rizi, Rahim R

    2011-02-01

    The aim of this study was to assess the utility of (3)He MRI to noninvasively probe the effects of positive end-expiratory pressure (PEEP) maneuvers on alveolar recruitment and atelectasis buildup in mechanically ventilated animals. Sprague-Dawley rats (n = 13) were anesthetized, intubated, and ventilated in the supine position ((4)He-to-O(2) ratio: 4:1; tidal volume: 10 ml/kg, 60 breaths/min, and inspiration-to-expiration ratio: 1:2). Recruitment maneuvers consisted of either a stepwise increase of PEEP to 9 cmH(2)O and back to zero end-expiratory pressure or alternating between these two PEEP levels. Diffusion MRI was performed to image (3)He apparent diffusion coefficient (ADC) maps in the middle coronal slices of lungs (n = 10). ADC was measured immediately before and after two recruitment maneuvers, which were separated from each other with a wait period (8-44 min). We detected a statistically significant decrease in mean ADC after each recruitment maneuver. The relative ADC change was -21.2 ± 4.1 % after the first maneuver and -9.7 ± 5.8 % after the second maneuver. A significant relative increase in mean ADC was observed over the wait period between the two recruitment maneuvers. The extent of this ADC buildup was time dependent, as it was significantly related to the duration of the wait period. The two postrecruitment ADC measurements were similar, suggesting that the lungs returned to the same state after the recruitment maneuvers were applied. No significant intrasubject differences in ADC were observed between the corresponding PEEP levels in two rats that underwent three repeat maneuvers. Airway pressure tracings were recorded in separate rats undergoing one PEEP maneuver (n = 3) and showed a significant relative difference in peak inspiratory pressure between pre- and poststates. These observations support the hypothesis of redistribution of alveolar gas due to recruitment of collapsed alveoli in presence of atelectasis, which was also supported by

  8. Exhaled nitric oxide and carbon monoxide in mechanically ventilated brain-injured patients.

    PubMed

    Korovesi, I; Kotanidou, A; Papadomichelakis, E; Livaditi, O; Sotiropoulou, C; Koutsoukou, A; Marczin, N; Orfanos, S E

    2016-03-01

    The inflammatory influence and biological markers of prolonged mechanical-ventilation in uninjured human lungs remains controversial. We investigated exhaled nitric oxide (NO) and carbon monoxide (CO) in mechanically-ventilated, brain-injured patients in the absence of lung injury or sepsis at two different levels of positive end-expiratory pressure (PEEP). Exhaled NO and CO were assessed in 27 patients, without lung injury or sepsis, who were ventilated with 8 ml kg(-1) tidal volumes under zero end-expiratory pressure (ZEEP group, n  =  12) or 8 cm H2O PEEP (PEEP group, n  =  15). Exhaled NO and CO was analysed on days 1, 3 and 5 of mechanical ventilation and correlated with previously reported markers of inflammation and gas exchange. Exhaled NO was higher on day 3 and 5 in both patient groups compared to day 1: (PEEP group: 5.8 (4.4-9.7) versus 11.7 (6.9-13.9) versus 10.7 (5.6-16.6) ppb (p  <  0.05); ZEEP group: 5.3 (3.8-8.8) versus 9.8 (5.3-12.4) versus 9.6 (6.2-13.5) ppb NO peak levels for days 1, 3 and 5, respectively, p  <  0.05). Exhaled CO remained stable on day 3 but significantly decreased by day 5 in the ZEEP group only (6.3 (4.3-9.0) versus 8.1 (5.8-12.1) ppm CO peak levels for day 5 versus 1, p  <  0.05). The change scores for peak exhaled CO over day 1 and 5 showed significant correlations with arterial blood pH and plasma TNF levels (r s  =  0.49, p  =  0.02 and r s  =  -0.51 p  =  0.02, respectively). Exhaled NO correlated with blood pH in the ZEEP group and with plasma levels of IL-6 in the PEEP group. We observed differential changes in exhaled NO and CO in mechanically-ventilated patients even in the absence of manifest lung injury or sepsis. These may suggest subtle pulmonary inflammation and support application of real time breath analysis for molecular monitoring in critically ill patients. PMID:26934167

  9. Selecting ventilator settings according to variables derived from the quasi-static pressure/volume relationship in patients with acute lung injury.

    PubMed

    Putensen, C; Baum, M; Hörmann, C

    1993-09-01

    Knowledge of the pressure/volume (P/V) relationship of the lung may allow selection of tidal volume and positive end-expiratory pressure (PEEP) to optimize gas exchange without adversely affecting lung function or hemodynamics. Ten patients with acute lung injury were stabilized on controlled mechanical ventilation, based on conventional practice, using criteria from arterial blood gas data. The P/V relationship was determined under quasi-static conditions (end-expiratory and end-inspiratory, no flow periods > 0.8 s) during mechanical ventilation with an automated procedure that changed PEEP in a stepwise fashion. Differences in expiratory tidal volumes before and after a change in PEEP equaled the change in functional residual capacity (delta FRC). PEEP was set above the lowest point of the steepest section of the P/V curve (inflection pressure) to prevent end-expiratory lung collapse. Inspiratory tidal volumes (VTI) were adjusted to avoid an end-inspiratory lung volume reaching the flat part of the P/V curve. Averaged delta FRC versus PEEP curves were shifted to the left and the slope increased 1, 6, and 12 h after changing ventilator settings compared to baseline (P < 0.01). Averaged baseline delta FRC versus PEEP curves showed a marked inflection pressure that decreased after adjusting ventilator settings (P < 0.01). PEEP was increased from 7.4 +/- 1.8 cm H2O (baseline) to 11.9 +/- 1.6 cm H2O (1 h) (P < 0.001) according to measured baseline inflection pressures. Simultaneously, VTI had to be reduced from 759 +/- 161 mL (baseline) to 664 +/- 101 mL (1 h) (P < 0.01) to avoid end-inspiratory overinflation. To maintain minute volume constant ventilator frequency was increased from 14 +/- 1.2 (baseline) to 16 +/- 1.2 breaths/min (1 h) (P < 0.01). Maximum quasi-static compliance of 38 +/- 7 mL/cm H2O (baseline) increased to 46 +/- 9 mL/cm H2O (1 h) (P < 0.01). Maintaining FIO2 constant, PaO2 increased from a baseline of 90 +/- 16 mm Hg to 122 +/- 24 mm Hg (1 h) (P

  10. The Effect of Hydrophilic and Hydrophobic Structure of Amphiphilic Polymeric Micelles on Their Transportation in Rats.

    PubMed

    Deng, Feiyang; Yu, Chao; Zhang, Hua; Dai, Wenbing; He, Bing; Zheng, Ying; Wang, Xueqing; Zhang, Qiang

    2016-01-01

    In the previous study, we have clarified how the hydrophilic and hydrophobic structures of amphiphilic polymers impact the transport of their micelles (PEEP-PCL, PEG-PCL and PEG-DSPE micelles) in epithelial MDCK cells (Biomaterials 2013, 34: 6284-6298). In this study, we attempt to clarify the behavior of the three micelles in rats. Coumarin-6 loaded micelles were injected into different sections of intestine of rats and observed by confocal laser scanning microscope (CLSM) or orally administrated and conducted pharmacokinetic study. All of the three kinds of micelles were able to cross the intestinal epithelial cells and enter blood circulation. The PEEP-PCL micelles demonstrated the fastest distribution mainly in duodenum, while the PEGDSPE micelles showed the longest distribution with the highest proportion in ileum of the three. No significant difference was observed among the pharmacokinetic parameters of the three micelles. The results were consistent in the two analysis methods mentioned above, yet there were some differences between in vivo and in vitro results reported previously. It might be the distinction between the environments in MDCK model and intestine that led to the discrepancy. The hydrophobicity of nanoparticles could both enhance uptake and hinder the transport across the mucus. However, there was no intact mucus in MDCK model, which preferred hydrophobic nanoparticles. PEEP was the most hydrophilic material constructing the micelles in the study and its uptake would be increased in rats compared to that in MDCK model, while DSPE was more hydrophobic than the others and MDCK model would be more ideal for its uptake. Considering the inconsistency of the results in the two models, whether the methods researchers were generally using at present were reasonable needs further investigation. PMID:26201346

  11. Sustained inflation at birth did not protect preterm fetal sheep from lung injury.

    PubMed

    Hillman, Noah H; Kemp, Matthew W; Noble, Peter B; Kallapur, Suhas G; Jobe, Alan H

    2013-09-15

    Sustained lung inflations (SI) at birth may recruit functional residual capacity (FRC). Clinically, SI increase oxygenation and decrease need for intubation in preterm infants. We tested whether a SI to recruit FRC would decrease lung injury from subsequent ventilation of fetal, preterm lambs. The preterm fetus (128±1 day gestation) was exteriorized from the uterus, a tracheostomy was performed, and fetal lung fluid was removed. While maintaining placental circulation, fetuses were randomized to one of four 15-min interventions: 1) positive end-expiratory pressure (PEEP) 8 cmH2O (n=4), 2) 20 s SI to 50 cmH2O then PEEP 8 cmH2O (n=10), 3) mechanical ventilation at tidal volume (VT) 7 ml/kg (n=13), or 4) 20 s SI then ventilation at VT 7 ml/kg (n=13). Lambs were ventilated with 95% N2/5% CO2 and PEEP 8 cmH2O. Volume recruitment was measured during SI, and fetal tissues were collected after an additional 30 min on placental support. SI achieved a mean FRC recruitment of 15 ml/kg (range 8-27). Fifty percent of final FRC was achieved by 2 s, 65% by 5 s, and 90% by 15 s, demonstrating prolonged SI times are needed to recruit FRC. SI alone released acute-phase proteins into the fetal lung fluid and increased mRNA expression of proinflammatory cytokines and acute-phase response genes in the lung. Mechanical ventilation further increased all markers of lung injury. SI before ventilation, regardless of the volume of FRC recruited, did not alter the acute-phase and proinflammatory responses to mechanical ventilation at birth. PMID:23873843

  12. Particle Size Concentration Distribution and Influences on Exhaled Breath Particles in Mechanically Ventilated Patients

    PubMed Central

    Chen, Yi-Fang; Huang, Sheng-Hsiu; Wang, Yu-Ling; Chen, Chun-Wan

    2014-01-01

    Humans produce exhaled breath particles (EBPs) during various breath activities, such as normal breathing, coughing, talking, and sneezing. Airborne transmission risk exists when EBPs have attached pathogens. Until recently, few investigations had evaluated the size and concentration distributions of EBPs from mechanically ventilated patients with different ventilation mode settings. This study thus broke new ground by not only evaluating the size concentration distributions of EBPs in mechanically ventilated patients, but also investigating the relationship between EBP level and positive expiratory end airway pressure (PEEP), tidal volume, and pneumonia. This investigation recruited mechanically ventilated patients, with and without pneumonia, aged 20 years old and above, from the respiratory intensive care unit of a medical center. Concentration distributions of EBPs from mechanically ventilated patients were analyzed with an optical particle analyzer. This study finds that EBP concentrations from mechanically ventilated patients during normal breathing were in the range 0.47–2,554.04 particles/breath (0.001–4.644 particles/mL). EBP concentrations did not differ significantly between the volume control and pressure control modes of the ventilation settings in the mechanically ventilated patients. The patient EBPs were sized below 5 µm, and 80% of them ranged from 0.3 to 1.0 µm. The EBPs concentrations in patients with high PEEP (> 5 cmH2O) clearly exceeded those in patients with low PEEP (≤ 5 cmH2O). Additionally, a significant negative association existed between pneumonia duration and EBPs concentration. However, tidal volume was not related to EBPs concentration. PMID:24475230

  13. Effects of respiratory mechanics on the capnogram phases: importance of dynamic compliance of the respiratory system

    PubMed Central

    2012-01-01

    Introduction The slope of phase III of the capnogram (SIII) relates to progressive emptying of the alveoli, a ventilation/perfusion mismatch, and ventilation inhomogeneity. SIII depends not only on the airway geometry, but also on the dynamic respiratory compliance (Crs); this latter effect has not been evaluated. Accordingly, we established the value of SIII for monitoring airway resistance during mechanical ventilation. Methods Sidestream capnography was performed during mechanical ventilation in patients undergoing elective cardiac surgery (n = 144). The airway resistance (Raw), total respiratory resistance and Crs displayed by the ventilator, the partial pressure of arterial oxygen (PaO2) and SIII were measured in time domain (ST-III) and in a smaller cohort (n = 68) by volumetry (SV-III) with and without normalization to the average CO2 phase III concentration. Measurements were performed at positive end-expiratory pressure (PEEP) levels of 3, 6 and 9 cmH2O in patients with healthy lungs (Group HL), and in patients with respiratory symptoms involving low (Group LC), medium (Group MC) or high Crs (Group HC). Results ST-III and SV-III exhibited similar PEEP dependencies and distribution between the protocol groups formed on the basis of Crs. A wide interindividual scatter was observed in the overall Raw-ST-III relationship, which was primarily affected by Crs. Decreases in Raw with increasing PEEP were reflected in sharp falls in SIII in Group HC, and in moderate decreases in SIII in Group MC, whereas ST-III was insensitive to changes in airway caliber in Groups LC and HL. Conclusions SIII assessed in the time domain and by volumetry provide meaningful information about alterations in airway caliber, but only within an individual patient. Although ST-III may be of value for bedside monitoring of the airway properties, its sensitivity depends on Crs. Thus, assessment of the capnogram shape should always be coupled with Crs when the airway resistance or

  14. Electroneutral composite polymersomes self-assembled by amphiphilic polyphosphazenes for effective miR-200c in vivo delivery to inhibit drug resistant lung cancer.

    PubMed

    Peng, Yan; Zhu, Xiumei; Qiu, Liyan

    2016-11-01

    MiR-200c has been confirmed to display remarkable effects on proliferation inhibition and apoptosis induction of certain cancer cells, but the main challenge for its successful translation into the clinic remains its effective delivery to the action site in vivo. In this study, a novel composite polyphosphazene vesicle system composed of amphiphilic [NP(PEG)0.3(EAB)1.7]n (PEEP) and weakly cationic [NP(PEG)0.5(DPA)1.5]n (PEDP) was prepared via a very simple dialysis method. The loading of miR-200c was accomplished with high efficiency by taking advantage of the combination effect of physical encapsulation and electrostatic interaction between vectors and miR-200c. The resultant miR-200c-loaded PEEP-PEDP polymersome (Nano-ED-200c) displayed suitable particle size, electric neutrality, excellent Ribonuclease stability and hemocompatibility. We also evaluated its subsequent miR-200c function in paclitaxel resistance human lung cancer (A549/T) cells in culture and tumor xenografts in nude mice. The results showed that Nano-ED-200c could achieve a higher miR-200c level and the enhanced antitumor efficacy with 68% tumor inhibition ratio at a very low dose of 1.0 mg/kg than PEEP nanoparticle, PEDP nanoparticle, even than Lipo2000. All these evidences indicated that this miR-200c delivery via polyphosphazene vesicles could act as a potential new therapeutic option for paclitaxel resistant human lung cancer. PMID:27541441

  15. Comparison of three manual ventilation devices using an intubated mannequin

    PubMed Central

    Hussey, S; Ryan, C; Murphy, B

    2004-01-01

    Objective: To compare three devices for manual neonatal ventilation. Design: Participants performed a two minute period of ventilation using a self inflating device, an anaesthesia bag with attached manometer, and a Neopuff device. An intubated neonatal mannequin, approximating a 1 kg infant with functional lungs, was used for the study. Target ventilation variables included a rate of 40 breaths per minute, peak inspiratory pressure (PIP) of 20 cm H2O, and positive end expiratory pressure (PEEP) of 4 cm H2O. The circuit was attached to a laptop computer for data recording. Results: Thirty five participants were enrolled, including consultant neonatologists, paediatricians, and anaesthetists, paediatric and anaesthetic registrars, and neonatal nurses. The maximum PIP recorded using the self inflating bag, anaesthetic bag, and Neopuff device were 75.9, 35.5, and 22.4 cm H2O respectively. There were significant differences between the devices for mean PIP (30.7, 18.1, and 20.1 cm H2O), mean PEEP (0.2, 2.8, and 4.4 cm H2O), mean airway pressure (7.6, 8.5, and 10.9 cm H2O), % total breaths ⩽ 21 cm H2O PIP (39%, 92%, and 98%), and % total breaths ⩾ 30 cm H2O PIP (45%, 0, and 0). There was no difference between doctors and allied health professionals for the variables examined. Conclusion: The anaesthetic bag with manometer and Neopuff device both facilitate accurate and reproducible manual ventilation. Self inflating devices without modifications are not as consistent by comparison and should incorporate a manometer and a PEEP device, particularly when used for resuscitation of very low birthweight infants. PMID:15499138

  16. Sustained inflation at birth did not protect preterm fetal sheep from lung injury

    PubMed Central

    Kemp, Matthew W.; Noble, Peter B.; Kallapur, Suhas G.; Jobe, Alan H.

    2013-01-01

    Sustained lung inflations (SI) at birth may recruit functional residual capacity (FRC). Clinically, SI increase oxygenation and decrease need for intubation in preterm infants. We tested whether a SI to recruit FRC would decrease lung injury from subsequent ventilation of fetal, preterm lambs. The preterm fetus (128 ± 1 day gestation) was exteriorized from the uterus, a tracheostomy was performed, and fetal lung fluid was removed. While maintaining placental circulation, fetuses were randomized to one of four 15-min interventions: 1) positive end-expiratory pressure (PEEP) 8 cmH2O (n = 4), 2) 20 s SI to 50 cmH2O then PEEP 8 cmH2O (n = 10), 3) mechanical ventilation at tidal volume (VT) 7 ml/kg (n = 13), or 4) 20 s SI then ventilation at VT 7 ml/kg (n = 13). Lambs were ventilated with 95% N2/5% CO2 and PEEP 8 cmH2O. Volume recruitment was measured during SI, and fetal tissues were collected after an additional 30 min on placental support. SI achieved a mean FRC recruitment of 15 ml/kg (range 8–27). Fifty percent of final FRC was achieved by 2 s, 65% by 5 s, and 90% by 15 s, demonstrating prolonged SI times are needed to recruit FRC. SI alone released acute-phase proteins into the fetal lung fluid and increased mRNA expression of proinflammatory cytokines and acute-phase response genes in the lung. Mechanical ventilation further increased all markers of lung injury. SI before ventilation, regardless of the volume of FRC recruited, did not alter the acute-phase and proinflammatory responses to mechanical ventilation at birth. PMID:23873843

  17. Mechanical Ventilation in Patients with the Acute Respiratory Distress Syndrome and Treated with Extracorporeal Membrane Oxygenation: Impact on Hospital and 30 Day Postdischarge Survival.

    PubMed

    Modrykamien, Ariel M; Hernandez, Omar O; Im, Yunhee; Walters, Ryan W; Schrader, Caleb L; Smith, Lauren E; Lima, Brian

    2016-01-01

    Mechanical ventilation support for acute respiratory distress syndrome (ARDS) patients involves the use of low tidal volumes and positive end-expiratory pressure. Nevertheless, the optimal ventilator strategy for ARDS patients undergoing extracorporeal membrane oxygenation (ECMO) therapy remains unknown. A retrospective analysis of a consecutive series of adult ARDS patients treated with V-V ECMO from October 2012 to May 2015 was performed. Mechanical ventilation data, as well as demographic and clinical data, were collected. We assessed the association between ventilator data and outcomes of interest. The primary outcome was hospital survival. Secondary outcome was 30 day survival posthospital discharge. Sixty-four ARDS patients were treated with ECMO. Univariate analysis showed that plateau pressure was independently associated with hospital survival. Tidal volume, positive end-expiratory pressure (PEEP), and plateau were independently associated with 30 day survival. Multivariate analysis, after controlling for covariates, revealed that a 1 unit increase in plateau pressure was associated with a 21% decrease in the odds of hospital survival (95% confidence interval [CI] = 6.39-33.42%, p = 0.007). In regards to 30 day survival postdischarge, a 1 unit increase in plateau pressure was associated with a 14.4% decrease in the odds of achieving the aforementioned outcome (95% CI = 1.75-25.4%, p = 0.027). Also, a 1 unit increase in PEEP was associated with a 36.2% decrease in the odds of 30 day survival (95% CI = 10.8-54.4%, p = 0.009). Among ARDS patients undergoing ECMO therapy, only plateau pressure is associated with hospital survival. Plateau pressure and PEEP are both associated with 30 day survival posthospital discharge. PMID:27347707

  18. The static pressure-volume relationship of the respiratory system determined with a computer-controlled ventilator.

    PubMed

    Svantesson, C; Drefeldt, B; Jonson, B

    1997-07-01

    The pressure-volume relationship of the respiratory system offers a guideline for setting of ventilators. The occlusion method for determination of the static elastic pressure-volume (Pel(st)/V) relationship is used as a reference and the aim of the study was to improve it with respect to time consumption and precision of recording and analysis. The inspiratory Pel(st)/V curve was determined with a computer-controlled ventilator using its pressure and flow sensors. During an automated procedure, an operator-defined volume history preceded each of a number of study breaths. These were interrupted at different volumes evenly distributed over a predefined volume interval. Total positive end-expiratory pressure (PEEP) was measured and could be separated into its components, external PEEP and auto-PEEP. The volume relationship between the curve and the current tidal volume was defined. An analytical method for definition of a linear segment of the Pel(st)/V curve and determination of its compliance is presented. In eight healthy human anaesthetized subjects duplicate Pel(st)/V curves were studied with respect to compliance and the position along the volume axis of the linear segment. The difference in compliance between measurements was 1.6 +/- 1.3 ml cmH2O(-1) or 1.2 +/- 0.9%. The position of the curve differed between measurements by 15 +/- 10 ml or by 1.1 +/- 0.9%. In a patient with acute lung injury the feasibility of applying a numerical method for a more detailed description of the Pel(st)/V curve was illustrated. PMID:19361153

  19. Laparoscopy-assisted orchiopexy versus laparoscopic two-stage fowler stephens orchiopexy for nonpalpable testes: Comparative study

    PubMed Central

    Alzahem, Abdulrahman

    2013-01-01

    Background/Purpose: To assess the outcome of the primary laparoscopy-assisted orchiopexy (LAO) and the laparoscopic two-stage Fowler Stephens orchiopexy (FSO) for managing patients with nonpalpable testis in terms of safety, feasibility and efficacy. Materials and Methods: This study included 94 patients (110 nonpalpable testes) who underwent laparoscopy at King Khalid University Hospital, Riyadh between July 1998 and June 2012. Patients were evaluated postoperatively to check the location and size of testes and to exclude any other complications. Results: Mean age at presentation was 24+/−19 months (9-96 months). Orchiectomy was done for 5 atrophic testes. 36 open orchiopexy was done for 29 canalicular testes and 7 peeping testes. 35 LAO were done for 1 canalicular testis, 5 peeping testes, 16 low intraabdominal testes and 13 high intraabdominal testes. 34 FSO were done for 23 high intraabdominal testes, 9 low intraabdominal testes and 2 peeping testes. Median follow up was 12 months (1-84 months) and 6 patients were lost to follow up. The overall success rates for LAO and FSO were 88% and 63%, respectively. Overall testicular atrophy rates were 3% and 30% for LAO and FSO, respectively (OR 0.08 [95% CI, 0.01-0.69], P = 0.006). For high intraabdominal testes, the atrophy rates were 3% and 20% for LAO and FSO, respectively (OR 0.14 [95% CI, 0.02-1.21, P = 0.049).Testicular displacement rates were 9% and 7% for LAO and FSO, respectively (OR 1.5, 95% CI, 0.24-9.59, P = 0.514). Conclusions: Laparoscopy provides a safe and accurate modality for diagnosing and managing patients with nonpalpable testes. LAO appears to be feasible and effective in management of high intraabdominal testes. Further well-conducted comparative studies are needed. PMID:23798870

  20. Personalizing mechanical ventilation for acute respiratory distress syndrome.

    PubMed

    Berngard, S Clark; Beitler, Jeremy R; Malhotra, Atul

    2016-03-01

    Lung-protective ventilation with low tidal volumes remains the cornerstone for treating patient with acute respiratory distress syndrome (ARDS). Personalizing such an approach to each patient's unique physiology may improve outcomes further. Many factors should be considered when mechanically ventilating a critically ill patient with ARDS. Estimations of transpulmonary pressures as well as individual's hemodynamics and respiratory mechanics should influence PEEP decisions as well as response to therapy (recruitability). This summary will emphasize the potential role of personalized therapy in mechanical ventilation. PMID:27076966

  1. Expiratory washout versus optimization of mechanical ventilation during permissive hypercapnia in patients with severe acute respiratory distress syndrome.

    PubMed

    Richecoeur, J; Lu, Q; Vieira, S R; Puybasset, L; Kalfon, P; Coriat, P; Rouby, J J

    1999-07-01

    The aim of this study was to compare three ventilatory techniques for reducing PaCO2 in patients with severe acute respiratory distress syndrome treated with permissive hypercapnia: (1) expiratory washout alone at a flow of 15 L/min, (2) optimized mechanical ventilation defined as an increase in the respiratory frequency to the maximal rate possible without development of intrinsic positive end- expiratory pressure (PEEP) combined with a reduction of the instrumental dead space, and (3) the combination of both methods. Tidal volume was set according to the pressure-volume curve in order to obtain an inspiratory plateau airway pressure equal to the upper inflection point minus 2 cm H2O after setting the PEEP at 2 cm H2O above the lower inflection point and was kept constant throughout the study. The three modalities were compared at the same inspiratory plateau airway pressure through an adjustment of the extrinsic PEEP. During conventional mechanical ventilation using a respiratory frequency of 18 breaths/min, respiratory acidosis (PaCO2 = 84 +/- 24 mm Hg and pH = 7.21 +/- 0.12) was observed. Expiratory washout and optimized mechanical ventilation (respiratory frequency of 30 +/- 4 breaths/min) had similar effects on CO2 elimination (DeltaPaCO2 = -28 +/- 11% versus -27 +/- 12%). A further decrease in PaCO2 was observed when both methods were combined (DeltaPaCO2 = -46 +/- 7%). Extrinsic PEEP had to be reduced by 5.3 +/- 2.1 cm H2O during expiratory washout and by 7.3 +/- 1.3 cm H2O during the combination of the two modes, whereas it remained unchanged during optimized mechanical ventilation alone. In conclusion, increasing respiratory rate and reducing instrumental dead space during conventional mechanical ventilation is as efficient as expiratory washout to reduce PaCO2 in patients with severe ARDS and permissive hypercapnia. When used in combination, both techniques have additive effects and result in PaCO2 levels close to normal values. PMID:10390383

  2. New strategies for mechanical ventilation. Lung protective ventilation.

    PubMed

    Wilmoth, D

    1999-12-01

    Although research is ongoing, and there are no definitive data to mandate the final answer to the question of which ventilation strategies result in the most optimal outcomes, the consensus of clinicians today suggests that we limit FIO2 to nontoxic levels, limit ventilating pressures and volumes, and use PEEP levels adequate to recruit alveoli and prevent tidal collapse. The critical care nurse must remain vigilant in his or her review of current literature to maintain knowledge of the current recommendations for optimal MV strategies. PMID:10855109

  3. Fluorescent supramolecular micelles for imaging-guided cancer therapy

    NASA Astrophysics Data System (ADS)

    Sun, Mengmeng; Yin, Wenyan; Dong, Xinghua; Yang, Wantai; Zhao, Yuliang; Yin, Meizhen

    2016-02-01

    A novel smart fluorescent drug delivery system composed of a perylene diimide (PDI) core and block copolymer poly(d,l-lactide)-b-poly(ethyl ethylene phosphate) is developed and named as PDI-star-(PLA-b-PEEP)8. The biodegradable PDI-star-(PLA-b-PEEP)8 is a unimolecular micelle and can self-assemble into supramolecular micelles, called as fluorescent supramolecular micelles (FSMs), in aqueous media. An insoluble drug camptothecin (CPT) can be effectively loaded into the FSMs and exhibits pH-responsive release. Moreover, the FSMs with good biocompatibility can also be employed as a remarkable fluorescent probe for cell labelling because the maximum emission of PDI is beneficial for bio-imaging. The flow cytometry and confocal laser scanning microscopy analysis demonstrate that the micelles are easily endocytosed by cancer cells. In vitro and in vivo tumor growth-inhibitory studies reveal a better therapeutic effect of FSMs after CPT encapsulation when compared with the free CPT drug. The multifunctional FSM nanomedicine platform as a nanovehicle has great potential for fluorescence imaging-guided cancer therapy.A novel smart fluorescent drug delivery system composed of a perylene diimide (PDI) core and block copolymer poly(d,l-lactide)-b-poly(ethyl ethylene phosphate) is developed and named as PDI-star-(PLA-b-PEEP)8. The biodegradable PDI-star-(PLA-b-PEEP)8 is a unimolecular micelle and can self-assemble into supramolecular micelles, called as fluorescent supramolecular micelles (FSMs), in aqueous media. An insoluble drug camptothecin (CPT) can be effectively loaded into the FSMs and exhibits pH-responsive release. Moreover, the FSMs with good biocompatibility can also be employed as a remarkable fluorescent probe for cell labelling because the maximum emission of PDI is beneficial for bio-imaging. The flow cytometry and confocal laser scanning microscopy analysis demonstrate that the micelles are easily endocytosed by cancer cells. In vitro and in vivo tumor growth

  4. Measuring Sediment Exchange Rates On Two Intertidal Banks In The Trent/ouse System, Uk

    NASA Astrophysics Data System (ADS)

    Mitchell, S. B.; Lawler, D. M.; West, J. R.; Couperthwaite, J. S.

    Results from PEEP sensors installed at two inter-tidal sites at Burringham, on the Trent estuary, and Blacktoft, near the confluence of the Trent and Ouse rivers, York- shire, UK will be presented for the period 1 March 1997 to 28 September, 1997. The PEEP system allows detailed erosion and deposition event sequences to be monitored automatically, and this considerably improves process information collected. It con- sists of linear arrays of photovoltaic cells covering an active length of 200 mm, housed within a transparent acrylic tube (f=16 mm). Following insertion of the PEEP sen- sors in the bank, subsequent erosion of sediment reveals more photosensitive cells to light, which increases the recorded output voltage. Accretion of sediment causes the recorded output voltages to drop. The sensors are connected to a data logger. This sys- tem permits data to be obtained on the magnitude, timing and frequency of individual erosion and deposition events, and hence sediment cycling patterns on estuarine banks. These events can be related much more sensitively to local hydraulic and meteorolog- ical conditions such as wind speed, tidal range and river flow. This enables calibration of process-based models of sediment transport regime. The main conclusions to this study are as follows: (1) Spring tides lead to higher sediment deposition through in- creased sediment availability. Sediment availability is modified by the proximity of the turbidity maximum to the study site. (2) Erosion is linked with wind speed, with high wind events leading to locally generated waves, which cause removal of surface sediment. Episodic erosion due to collapse of ScliffS forms has also been observed for ´ the Burringham site. (3) Observed Erosion and deposition rates of up to 50 mm per day are generally 2-3 times higher for the Burringham site compared with the Black- toft site. This more dynamic environment may be related to higher tidal velocities, and steeper banks at Burringham

  5. Simulating matched filter detection of ionized bubble around a quasar in the epoch of reionization

    NASA Astrophysics Data System (ADS)

    Majumdar, Suman; Bharadwaj, Somnath; Choudhury, Tirthankar Roy

    2012-12-01

    The recent discovery of the z = 7.085 quasar has opened up a new window to peep into the inter galactic medium during the epoch of reionization (EoR). The detection of the ionized region around such a high redshift quasar is in principle capable of constraining the neutral fraction of the IGM and the quasar's age. Here we present the possibility of detection of such an ionized region around a quasar at z = 8 using redshifted 21-cm observations of the neutral hydrogen and possible ways to constrain IGM neutral fraction and quasar's age through this detection.

  6. Personalizing mechanical ventilation for acute respiratory distress syndrome

    PubMed Central

    Beitler, Jeremy R.; Malhotra, Atul

    2016-01-01

    Lung-protective ventilation with low tidal volumes remains the cornerstone for treating patient with acute respiratory distress syndrome (ARDS). Personalizing such an approach to each patient’s unique physiology may improve outcomes further. Many factors should be considered when mechanically ventilating a critically ill patient with ARDS. Estimations of transpulmonary pressures as well as individual’s hemodynamics and respiratory mechanics should influence PEEP decisions as well as response to therapy (recruitability). This summary will emphasize the potential role of personalized therapy in mechanical ventilation. PMID:27076966

  7. Lung Transcriptomics during Protective Ventilatory Support in Sepsis-Induced Acute Lung Injury

    PubMed Central

    Acosta-Herrera, Marialbert; Lorenzo-Diaz, Fabian; Pino-Yanes, Maria; Corrales, Almudena; Valladares, Francisco; Klassert, Tilman E.; Valladares, Basilio; Slevogt, Hortense; Ma, Shwu-Fan

    2015-01-01

    Acute lung injury (ALI) is a severe inflammatory process of the lung. The only proven life-saving support is mechanical ventilation (MV) using low tidal volumes (LVT) plus moderate to high levels of positive end-expiratory pressure (PEEP). However, it is currently unknown how they exert the protective effects. To identify the molecular mechanisms modulated by protective MV, this study reports transcriptomic analyses based on microarray and microRNA sequencing in lung tissues from a clinically relevant animal model of sepsis-induced ALI. Sepsis was induced by cecal ligation and puncture (CLP) in male Sprague-Dawley rats. At 24 hours post-CLP, septic animals were randomized to three ventilatory strategies: spontaneous breathing, LVT (6 ml/kg) plus 10 cmH2O PEEP and high tidal volume (HVT, 20 ml/kg) plus 2 cmH2O PEEP. Healthy, non-septic, non-ventilated animals served as controls. After 4 hours of ventilation, lung samples were obtained for histological examination and gene expression analysis using microarray and microRNA sequencing. Validations were assessed using parallel analyses on existing publicly available genome-wide association study findings and transcriptomic human data. The catalogue of deregulated processes differed among experimental groups. The ‘response to microorganisms’ was the most prominent biological process in septic, non-ventilated and in HVT animals. Unexpectedly, the ‘neuron projection morphogenesis’ process was one of the most significantly deregulated in LVT. Further support for the key role of the latter process was obtained by microRNA studies, as four species targeting many of its genes (Mir-27a, Mir-103, Mir-17-5p and Mir-130a) were found deregulated. Additional analyses revealed 'VEGF signaling' as a central underlying response mechanism to all the septic groups (spontaneously breathing or mechanically ventilated). Based on this data, we conclude that a co-deregulation of 'VEGF signaling' along with 'neuron projection

  8. Mitogen-activated Protein Kinase Phosphatase-1 Modulates Regional Effects of Injurious Mechanical Ventilation in Rodent Lungs

    PubMed Central

    Park, Moo Suk; Edwards, Michael G.; Sergew, Amen; Riches, David W. H.; Albert, Richard K.

    2012-01-01

    Rationale: Mechanical ventilation induces heterogeneous lung injury by mitogen-activated protein kinase (MAPK) and nuclear factor-κB. Mechanisms regulating regional injury and protective effects of prone positioning are unclear. Objectives: To determine the key regulators of the lung regional protective effects of prone positioning in rodent lungs exposed to injurious ventilation. Methods: Adult rats were ventilated with high (18 ml/kg, positive end-expiratory pressure [PEEP] 0) or low Vt (6 ml/kg; PEEP 3 cm H2O; 3 h) in supine or prone position. Dorsal–caudal lung mRNA was analyzed by microarray and MAPK phosphatases (MKP)-1 quantitative polymerase chain reaction. MKP-1−/− or wild-type mice were ventilated with very high (24 ml/kg; PEEP 0) or low Vt (6–7 ml/kg; PEEP 3 cm H2O). The MKP-1 regulator PG490-88 (MRx-108; 0.75 mg/kg) or phosphate-buffered saline was administered preventilation. Injury was assessed by lung mechanics, bronchioalveolar lavage cell counts, protein content, and lung injury scoring. Immunoblotting for MKP-1, and IκBα and cytokine ELISAs were performed on lung lysates. Measurements and Main Results: Prone positioning was protective against injurious ventilation in rats. Expression profiling demonstrated MKP-1 20-fold higher in rats ventilated prone rather than supine and regional reduction in p38 and c-jun N-terminal kinase activation. MKP-1−/− mice experienced amplified injury. PG490-88 improved static lung compliance and injury scores, reduced bronchioalveolar lavage cell counts and cytokine levels, and induced MKP-1 and IκBα. Conclusions: Injurious ventilation induces MAPK in an MKP-1–dependent fashion. Prone positioning is protective and induces MKP-1. PG490-88 induced MKP-1 and was protective against high Vt in a nuclear factor-κB–dependent manner. MKP-1 is a potential target for modulating regional effects of injurious ventilation. PMID:22582160

  9. Predicting ventilator-induced lung injury using a lung injury cost function.

    PubMed

    Hamlington, Katharine L; Smith, Bradford J; Allen, Gilman B; Bates, Jason H T

    2016-07-01

    Managing patients with acute respiratory distress syndrome (ARDS) requires mechanical ventilation that balances the competing goals of sustaining life while avoiding ventilator-induced lung injury (VILI). In particular, it is reasonable to suppose that for any given ARDS patient, there must exist an optimum pair of values for tidal volume (VT) and positive end-expiratory pressure (PEEP) that together minimize the risk for VILI. To find these optimum values, and thus develop a personalized approach to mechanical ventilation in ARDS, we need to be able to predict how injurious a given ventilation regimen will be in any given patient so that the minimally injurious regimen for that patient can be determined. Our goal in the present study was therefore to develop a simple computational model of the mechanical behavior of the injured lung in order to calculate potential injury cost functions to serve as predictors of VILI. We set the model parameters to represent normal, mildly injured, and severely injured lungs and estimated the amount of volutrauma and atelectrauma caused by ventilating these lungs with a range of VT and PEEP. We estimated total VILI in two ways: 1) as the sum of the contributions from volutrauma and atelectrauma and 2) as the product of their contributions. We found the product provided estimates of VILI that are more in line with our previous experimental findings. This model may thus serve as the basis for the objective choice of mechanical ventilation parameters for the injured lung. PMID:27174922

  10. Postflight hardware evaluation 360T026 (RSRM-26, STS-47)

    NASA Technical Reports Server (NTRS)

    Nielson, Greg

    1993-01-01

    The final report for the Clearfield disassembly evaluation and a continuation of the KSC postflight assessment for the 360T026 (STS-47) Redesigned Solid Rocket Motor (RSRM) flight set is provided. All observed hardware conditions were documented on PFOR's and are included in Appendices A, B, and C. Appendices D and E contain the measurements and safety factor data for the nozzle and insulation components. This report, along with the KSC Ten-Day Postflight Hardware Evaluation Report (TWR-64203), represents a summary of the 360T026 hardware evaluation. The as-flown hardware configuration is documented in TWR-60472. Disassembly evaluation photograph numbers are logged in TWA-1987. The 360T026 flight set disassembly evaluations described were performed at the RSRM Refurbishment Facility in Clearfield, Utah. The final factory joint demate occurred on 12 April 1993. Detailed evaluations were performed in accordance with the Clearfield Postflight Engineering Evaluation Plan (PEEP), TWR-50051, Revision A. All observations were compared against limits that are also defined in the PEEP. These limits outline the criteria for categorizing the observations as acceptable, reportable, or critical. Hardware conditions that were unexpected and/or determined to be reportable or critical were evaluated by the applicable CPT and tracked through the PFAR system.

  11. Partial liquid ventilation improves lung function in ventilation-induced lung injury.

    PubMed

    Vazquez de Anda, G F; Lachmann, R A; Verbrugge, S J; Gommers, D; Haitsma, J J; Lachmann, B

    2001-07-01

    Disturbances in lung function and lung mechanics are present after ventilation with high peak inspiratory pressures (PIP) and low levels of positive end-expiratory pressure (PEEP). Therefore, the authors investigated whether partial liquid ventilation can re-establish lung function after ventilation-induced lung injury. Adult rats were exposed to high PIP without PEEP for 20 min. Thereafter, the animals were randomly divided into five groups. The first group was killed immediately after randomization and used as an untreated control. The second group received only sham treatment and ventilation, and three groups received treatment with perfluorocarbon (10 mL x kg(-1), 20 mL x kg(-1), and 20 ml x kg(-1) plus an additional 5 mL x kg(-1) after 1 h). The four groups were maintained on mechanical ventilation for a further 2-h observation period. Blood gases, lung mechanics, total protein concentration, minimal surface tension, and small/large surfactant aggregates ratio were determined. The results show that in ventilation-induced lung injury, partial liquid ventilation with different amounts of perflubron improves gas exchange and pulmonary function, when compared to a group of animals treated with standard respiratory care. These effects have been observed despite the presence of a high intra-alveolar protein concentration, especially in those groups treated with 10 and 20 mL of perflubron. The data suggest that replacement of perfluorocarbon, lost over time, is crucial to maintain the constant effects of partial liquid ventilation. PMID:11510811

  12. The safety of the open lung approach in neurosurgical patients.

    PubMed

    Wolf, S; Schürer, L; Trost, H A; Lumenta, C B

    2002-01-01

    A recent randomized controlled trial in patients with ARDS showed the beneficial effect of mechanical ventilation according to the so called Open Lung Approach, consisting of low tidal volumes and elevated PEEP settings after performing recruiting maneuvers. However, neurosurgical patients were excluded from this and other ARDS trials due to concerns of intracranial deterioration. In this report, we present the clinical data of eleven patients with known intracranial pathology and concomitant ARDS which was treated according to the Open Lung concept. The mean oxygenation index (paO2/FiO2) increased from 132 +/- 88 to 325 +/- 64 measured 24 hours after initiation of Open Lung ventilation (p < 0.001). Mean PEEP level after the first recruiting maneuver was 14.9 +/- 3.2 mmHg. Comparison of mean and peak ICP values over 24 hours of time before and after the first recruitment maneuver revealed a non-significant decline in ICP despite a moderate increase in mean paCO2. Although two patients needed additional ICP treatment, no patient had to be withdrawn from Open Lung ventilation. In our series, Open Lung ventilation in neurosurgical patients with ARDS was a safe method to improve oxygenation. Careful ICP monitoring provided, there is no reason to withhold this modern ARDS treatment in the neurosurgical intensive care unit. PMID:12168369

  13. Endomicroscopic analysis of time- and pressure-dependent area of subpleural alveoli in mechanically ventilated rats.

    PubMed

    Runck, Hanna; Schwenninger, David; Haberstroh, Jörg; Guttmann, Josef

    2014-11-01

    We investigated the effects of recruitment maneuvers on subpleural alveolar area in healthy rats. 36 mechanically ventilated rats were allocated to either ZEEP-group or PEEP - 5cmH2O - group. The subpleural alveoli were observed using a transthoracal endoscopic imaging technique. Two consecutive low-flow maneuvers up to 30cmH2O peak pressure each were performed, interrupted by 5s plateau phases at four different pressure levels. Alveolar area change at maneuver peak pressures and during the plateau phases was calculated and respiratory system compliance before and after the maneuvers was analyzed. In both groups alveolar area at the second peak of the maneuver did not differ significantly compared to the first peak. During the plateau phases there was a slight increase in alveolar area. After the maneuvers, compliance increased by 30% in ZEEP group and 20% in PEEP group. We conclude that the volume insufflated by the low-flow recruitment maneuver is distributed to deeper but not to subpleural lung regions. PMID:25150503

  14. Influence of lung volume on phrenic, hypoglossal and mylohyoid nerve activities.

    PubMed

    Bartlett, D; St John, W M

    1988-07-01

    In decerebrate, paralyzed cats, ventilated by a servo-respirator in accordance with phrenic nerve activity, we examined the influence of lung volume on the activities of the phrenic, hypoglossal and mylohyoid nerves. When lung inflation was briefly withheld, the durations of inspiration (TI) and expiration (TE) and the activities of all three nerves increased. The relative increase in hypoglossal activity greatly exceeded that of phrenic activity and was apparent earlier in the course of inspiration. This hypoglossal response was enhanced by hypercapnia and isocapnic hypoxia. The responses of mylohyoid activity were quite variable: withholding lung inflation augmented inspiratory activity in some cats, but expiratory discharge in others. Sustained increases in end-expiratory lung volume were induced by application of 3-4 cm H2O of positive end-expiratory pressure (PEEP). Steady-state PEEP did not influence nerve activities or the breathing pattern. Bilateral vagotomy increased TI, TE, and the activities of all three nerves. No response to withoholding lung inflation could be discerned after vagal section. The results provide further definition of the influence of vagally mediated, lung volume dependent reflexes on the control of upper airway muscles. These reflexes are well suited to relieve or prevent upper airway obstruction. PMID:3051235

  15. Performance of ICU ventilators during noninvasive ventilation with large leaks in a total face mask: a bench study* **

    PubMed Central

    Nakamura, Maria Aparecida Miyuki; Costa, Eduardo Leite Vieira; Carvalho, Carlos Roberto Ribeiro; Tucci, Mauro Roberto

    2014-01-01

    Objective: Discomfort and noncompliance with noninvasive ventilation (NIV) interfaces are obstacles to NIV success. Total face masks (TFMs) are considered to be a very comfortable NIV interface. However, due to their large internal volume and consequent increased CO2 rebreathing, their orifices allow proximal leaks to enhance CO2 elimination. The ventilators used in the ICU might not adequately compensate for such leakage. In this study, we attempted to determine whether ICU ventilators in NIV mode are suitable for use with a leaky TFM. Methods: This was a bench study carried out in a university research laboratory. Eight ICU ventilators equipped with NIV mode and one NIV ventilator were connected to a TFM with major leaks. All were tested at two positive end-expiratory pressure (PEEP) levels and three pressure support levels. The variables analyzed were ventilation trigger, cycling off, total leak, and pressurization. Results: Of the eight ICU ventilators tested, four did not work (autotriggering or inappropriate turning off due to misdetection of disconnection); three worked with some problems (low PEEP or high cycling delay); and one worked properly. Conclusions: The majority of the ICU ventilators tested were not suitable for NIV with a leaky TFM. PMID:25029653

  16. 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. PMID:22136584

  17. Customization of an open-lung ventilation strategy to treat a case of life-threatening acute respiratory distress syndrome.

    PubMed

    Grooms, David A; Sibole, Stephen H; Tomlinson, James R; Marik, Paul E; Chatburn, Robert L

    2011-04-01

    The ARDS Network low-tidal-volume protocol is considered the standard of care for patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). The protocol is built on the foundation of low-tidal-volume ventilation, use of a combined PEEP and F(IO(2)) table, and managing alveolar end-inspiratory pressure by limiting the plateau airway pressure to ≤ 30 cm H(2)O. Although this strategy, to date, is the only method that significantly improves ALI/ARDS survival, alternative methods of improving hypoxemia and minimizing ventilator-induced lung injury, in conjunction with low-tidal-volume ventilation, can be used for life-threatening ARDS. We present a case in which we customized the use of alveolar recruitment maneuvers by analyzing the hysteresis of the pressure-volume curve to assess lung recruitability, decremental PEEP to sustain lung recruitment, and careful use of plateau pressure ≥ 30 cm H(2)O, which improved our patient's life-threatening hypoxemia within the first 36 min of arrival to our ICU. PMID:21255504

  18. Circulatory effects of fast ventilator rates in preterm infants.

    PubMed Central

    Fenton, A C; Field, D J; Woods, K L; Evans, D H; Levene, M I

    1990-01-01

    High frequency positive pressure ventilation has been suggested to result in a lower incidence of respiratory complications in preterm infants with idiopathic respiratory distress syndrome compared with ventilation at conventional rates. A possible disadvantage is compromise of the infant's cardiovascular condition secondary to inadvertent positive end expiratory pressure (PEEP). In a group of 20 such infants treated with high frequency positive pressure ventilation (rates of up to 100/minute) and analysed, changes in arterial blood pressure and cerebral blood flow velocity were largely influenced by changes in arterial blood gases, and no effect could be attributed to inadvertent PEEP. In addition, the observed fall in both arterial carbon dioxide and oxygen tensions could be readily predicted for theoretical reasons. Under certain conditions at the fastest rates used, cerebral blood flow velocity was significantly influenced by changes in blood pressure, which may indicate impaired cerebrovascular regulation. Though other factors (such as the severity of the infants' illness or the use of paralysis) may have been responsible for this apparent blood pressure passivity, the role of high frequency positive pressure ventilation in such infants warrants further study. PMID:2117423

  19. Short-term exposure to high-pressure ventilation leads to pulmonary biotrauma and systemic inflammation in the rat.

    PubMed

    Hoegl, Sandra; Boost, Kim A; Flondor, Michael; Scheiermann, Patrick; Muhl, Heiko; Pfeilschifter, Josef; Zwissler, Bernhard; Hofstetter, Christian

    2008-04-01

    Though often lifesaving, mechanical ventilation itself bears the risk of lung damage [ventilator-induced lung injury (VILI)]. The underlying molecular mechanisms have not been fully elucidated, but stress-induced mediators seem to play an important role in biotrauma related to VILI. Our purpose was to evaluate an animal model of VILI that allows the observation of pathophysiologic changes along with parameters of biotrauma. For VILI induction, rats (n=16) were ventilated with a peak airway pressure (pmax) of 45 cm H2O and end-expiratory pressure (PEEP) of 0 for 20 min, followed by an observation time of 4 h. In the control group (n=8) the animals were ventilated with a pmax of 20 cm H2O and PEEP of 4. High-pressure ventilation resulted in an increase in paCO2 and a decrease in paO2 and mean arterial pressure. Only 4 animals out of 16 survived 4 h and VILI lungs showed severe macroscopic and microscopic damage, oedema and neutrophil influx. High-pressure ventilation increased the cytokine levels of macrophage inflammatory protein-2 and IL-1beta in bronchoalveolar lavage and plasma. VILI also induced pulmonary heat shock protein-70 expression and the activity of matrix metalloproteinases. The animal model used enabled us to observe the effect of high-pressure ventilation on mortality, lung damage/function and biotrauma. Thus, by combining barotrauma with biotrauma, this animal model may be suitable for studying therapeutical approaches to VILI. PMID:18360698

  20. Sequelae of the adult respiratory distress syndrome.

    PubMed Central

    Hert, R.; Albert, R. K.

    1994-01-01

    Most survivors of ARDS have persistent mild reductions of TLCO even as long as a year after their episode. The lung volumes and flows return to normal in most instances, although a subset of patients will have persistent impairment. Both obstructive and restrictive deficits may be seen. This group may be predicted by the degree of acute lung injury assessed by the level of FIO2, PEEP, and gas exchange abnormality that exists in the first few days. In the first year after ARDS most physiological abnormalities will improve, but if deficits persist at one year further improvement is unlikely. Although many patients report dyspnoea following ARDS, the symptom does not correlate with abnormalities of pulmonary function. The possibility that conventional management may augment the degree of acute injury and worsen outcome must be considered. The effects of chronic hyperoxia in humans with acute lung injury or those of high levels of PEEP compared with low levels are not known. Exploring new ventilator management strategies while we await more specific treatment directed at the primary problem of acute lung inflammation will hopefully reduce acute mortality as well as acute and chronic morbidity. Images PMID:8153946

  1. Postflight hardware evaluation 360T025 (RSRM-25, STS-46)

    NASA Technical Reports Server (NTRS)

    Morgan, Ferral

    1993-01-01

    The final report for the Clearfield disassembly evaluation and a continuation of the KSC postflight assessment for the 360T025 (STS-46) Redesign Solid Rocket Motor (RSRM) flight set is presented. All observed hardware conditions were documented on PFOR's and are included in Appendices A through C. Appendices D and E contain the measurements and safety factor data for the nozzle and insulation components. Along with the KSC Ten-Day Postflight Hardware Evaluation Report (TWR-60687), a summary of the 360T025 hardware evaluation is provided. The as-flown hardware configuration is documented in TWR-60470. Disassembly evaluation photograph numbers are logged in TWA-1986. The 360T025 flight set disassembly evaluations described were performed at the RSRM Refurbishment Facility in Clearfield, Utah. The final factory joint demate occurred on 16 Mar. 1993. Detailed evaluations were performed in accordance with the Clearfield PEEP, TWR-50051, Revision A. All observations were compared against limits that are also defined in the PEEP. These limits outline the criteria for categorizing the observations as acceptable, reportable, or critical. Hardware conditions that were unexpected and/or determined to be reportable or critical were evaluated by the applicable CPT and tracked through the PFAR system.

  2. Effects of superimposed tissue weight on regional compliance of injured lungs.

    PubMed

    Pellegrini, Mariangela; Derosa, Savino; Tannoia, Angela; Rylander, Christian; Fiore, Tommaso; Larsson, Anders; Hedenstierna, Göran; Perchiazzi, Gaetano

    2016-07-01

    Computed tomography (CT), together with image analysis technologies, enable the construction of regional volume (VREG) and local transpulmonary pressure (PTP,REG) maps of the lung. Purpose of this study is to assess the distribution of VREG vs PTP,REG along the gravitational axis in healthy (HL) and experimental acute lung injury conditions (eALI) at various positive end-expiratory pressures (PEEPs) and inflation volumes. Mechanically ventilated pigs underwent inspiratory hold maneuvers at increasing volumes simultaneously with lung CT scans. eALI was induced via the iv administration of oleic acid. We computed voxel-level VREG vs PTP,REG curves into eleven isogravitational planes by applying polynomial regressions. Via F-test, we determined that VREG vs PTP,REG curves derived from different anatomical planes (p-values<1.4E-3), exposed to different PEEPs (p-values<1.5E-5) or subtending different lung status (p-values<3E-3) were statistically different (except for two cases of adjacent planes). Lung parenchyma exhibits different elastic behaviors based on its position and the density of superimposed tissue which can increase during lung injury. PMID:26976688

  3. Functional flexibility in wild bonobo vocal behaviour

    PubMed Central

    Archbold, Jahmaira; Zuberbühler, Klaus

    2015-01-01

    A shared principle in the evolution of language and the development of speech is the emergence of functional flexibility, the capacity of vocal signals to express a range of emotional states independently of context and biological function. Functional flexibility has recently been demonstrated in the vocalisations of pre-linguistic human infants, which has been contrasted to the functionally fixed vocal behaviour of non-human primates. Here, we revisited the presumed chasm in functional flexibility between human and non-human primate vocal behaviour, with a study on our closest living primate relatives, the bonobo (Pan paniscus). We found that wild bonobos use a specific call type (the “peep”) across a range of contexts that cover the full valence range (positive-neutral-negative) in much of their daily activities, including feeding, travel, rest, aggression, alarm, nesting and grooming. Peeps were produced in functionally flexible ways in some contexts, but not others. Crucially, calls did not vary acoustically between neutral and positive contexts, suggesting that recipients take pragmatic information into account to make inferences about call meaning. In comparison, peeps during negative contexts were acoustically distinct. Our data suggest that the capacity for functional flexibility has evolutionary roots that predate the evolution of human speech. We interpret this evidence as an example of an evolutionary early transition away from fixed vocal signalling towards functional flexibility. PMID:26290789

  4. Protein adsorption is required for stealth effect of poly(ethylene glycol)- and poly(phosphoester)-coated nanocarriers.

    PubMed

    Schöttler, Susanne; Becker, Greta; Winzen, Svenja; Steinbach, Tobias; Mohr, Kristin; Landfester, Katharina; Mailänder, Volker; Wurm, Frederik R

    2016-04-01

    The current gold standard to reduce non-specific cellular uptake of drug delivery vehicles is by covalent attachment of poly(ethylene glycol) (PEG). It is thought that PEG can reduce protein adsorption and thereby confer a stealth effect. Here, we show that polystyrene nanocarriers that have been modified with PEG or poly(ethyl ethylene phosphate) (PEEP) and exposed to plasma proteins exhibit a low cellular uptake, whereas those not exposed to plasma proteins show high non-specific uptake. Mass spectrometric analysis revealed that exposed nanocarriers formed a protein corona that contains an abundance of clusterin proteins (also known as apolipoprotein J). When the polymer-modified nanocarriers were incubated with clusterin, non-specific cellular uptake could be reduced. Our results show that in addition to reducing protein adsorption, PEG, and now PEEPs, can affect the composition of the protein corona that forms around nanocarriers, and the presence of distinct proteins is necessary to prevent non-specific cellular uptake. PMID:26878141

  5. Postflight hardware evaluation (RSRM-29, STS-54)

    NASA Technical Reports Server (NTRS)

    1993-01-01

    This document is the final report for the Clearfield disassembly evaluation and a continuation of the KSC postflight assessment for the RSRM-29 flight set. All observed hardware conditions were documented on PFOR's and are included in Appendices A, B, and C. Appendices D and E contain the measurements and safety factor data for the nozzle and insulation components. This report, along with the KSC Ten-Day Postflight Hardware Evaluation Report (TWR-64221), represents a summary of the RSRM-29 hardware evaluation. Disassembly evaluation photograph numbers are logged in TWA-1990. The RSRM-29 flight set disassembly evaluations described in this document were performed at the RSRM Refurbishment Facility in Clearfield, Utah. The final factory joint demate occurred on September 9, 1993. Detailed evaluations were performed in accordance with the Clearfield PEEP, TWR-50051, Revision A. All observations were compared against limits that are also defined in the PEEP. These limits outline the criteria for categorizing the observations as acceptable, reportable, or critical. Hardware conditions that were unexpected and/or determined to be reportable or critical were evaluated by the applicable CPT and tracked through the PFAR system.

  6. Effects of altered ventilatory patterns of rabbit pulmonary endothelial angiotensin converting enzyme function, in vivo

    SciTech Connect

    Toivonen, H.J.; Catravas, J.D.

    1986-03-01

    Because alveolar pressure can influence pulmonary blood flow, volume and surface area, the authors have studied the effects of airway pressure on endothelial angiotensin converting enzyme (ACE) function in rabbit lungs in vivo, utilizing indicator dilution techniques with /sup 3/H-Benzoyl-Phe-Ala-Pro (BPAP) as substate. Static inclation of the lungs to a pressure of 0 or 5 mmHg did not change percent transpulmonary metabolism and Amax/Km ratio in comparison to control measurements during conventional mechanical ventilation. When the inflation pressure was increased to 10 mmHg, percent metabolism of /sup 3/H-BPAP remained unaltered but Amax/Km decreased over 40% from control. This decrease was in close relation to the reduction in pulmonary blood flow. Addition of 5 cm H/sub 2/O positive end-expiratory pressure (PEEP) to the mechanical ventilation also decreased Amax/Km values and pulmonary blood flow but did not influence percent metabolism of /sup 3/H-BPAP. These results suggest that the detected alterations in ACE kinetics were more likely due to hemodynamic changes than enzyme dysfunction. The authors propose that high static alveolar pressures as well as PEEP did not affect angiotensin converting enzyme function, but reduced the fraction of perfused microvessels reflected in changes in Amax/Km ratios.

  7. Protein adsorption is required for stealth effect of poly(ethylene glycol)- and poly(phosphoester)-coated nanocarriers

    NASA Astrophysics Data System (ADS)

    Schöttler, Susanne; Becker, Greta; Winzen, Svenja; Steinbach, Tobias; Mohr, Kristin; Landfester, Katharina; Mailänder, Volker; Wurm, Frederik R.

    2016-04-01

    The current gold standard to reduce non-specific cellular uptake of drug delivery vehicles is by covalent attachment of poly(ethylene glycol) (PEG). It is thought that PEG can reduce protein adsorption and thereby confer a stealth effect. Here, we show that polystyrene nanocarriers that have been modified with PEG or poly(ethyl ethylene phosphate) (PEEP) and exposed to plasma proteins exhibit a low cellular uptake, whereas those not exposed to plasma proteins show high non-specific uptake. Mass spectrometric analysis revealed that exposed nanocarriers formed a protein corona that contains an abundance of clusterin proteins (also known as apolipoprotein J). When the polymer-modified nanocarriers were incubated with clusterin, non-specific cellular uptake could be reduced. Our results show that in addition to reducing protein adsorption, PEG, and now PEEPs, can affect the composition of the protein corona that forms around nanocarriers, and the presence of distinct proteins is necessary to prevent non-specific cellular uptake.

  8. Final postflight hardware evaluation report RSRM-28 (STS-53)

    NASA Astrophysics Data System (ADS)

    Starrett, William David, Jr.

    1993-11-01

    The final report for the Clearfield disassembly evaluation and a continuation of the KSC postflight assessment for the RSRM-28 (STS-53) RSRM flight set is presented. All observed hardware conditions were documented on PFOR's and are included in Appendices A through C. Appendices D and E contain the measurements and safety factor data for the nozzle and insulation components. This report, along with the KSC Ten-Day Postflight Hardware Evaluation Report (TWR-64215), represents a summary of the RSRM-28 hardware evaluation. The as-flown hardware configuration is documented in TWR-63638. Disassembly evaluation photograph numbers are logged in TWA-1989. The RSRM-28 flight set disassembly evaluations described were performed at the RSRM Refurbishment Facility in Clearfield, Utah. The final factory joint demate occurred on July 15, 1993. Additional time was required to perform the evaluation of the stiffener rings per special issue 4.1.5.2 because of the washout schedule. The release of this report was after completion of all special issues per program management direction. Detailed evaluations were performed in accordance with the Clearfield PEEP, TWR-50051, Revision A. All observations were compared against limits that are also defined in the PEEP. These limits outline the criteria for categorizing the observations as acceptable, reportable, or critical. Hardware conditions that were unexpected and/or determined to be reportable or critical were evaluated by the applicable team and tracked through the PFAR system.

  9. Postflight hardware evaluation 360T025 (RSRM-25, STS-46)

    NASA Astrophysics Data System (ADS)

    Morgan, Ferral

    1993-03-01

    The final report for the Clearfield disassembly evaluation and a continuation of the KSC postflight assessment for the 360T025 (STS-46) Redesign Solid Rocket Motor (RSRM) flight set is presented. All observed hardware conditions were documented on PFOR's and are included in Appendices A through C. Appendices D and E contain the measurements and safety factor data for the nozzle and insulation components. Along with the KSC Ten-Day Postflight Hardware Evaluation Report (TWR-60687), a summary of the 360T025 hardware evaluation is provided. The as-flown hardware configuration is documented in TWR-60470. Disassembly evaluation photograph numbers are logged in TWA-1986. The 360T025 flight set disassembly evaluations described were performed at the RSRM Refurbishment Facility in Clearfield, Utah. The final factory joint demate occurred on 16 Mar. 1993. Detailed evaluations were performed in accordance with the Clearfield PEEP, TWR-50051, Revision A. All observations were compared against limits that are also defined in the PEEP. These limits outline the criteria for categorizing the observations as acceptable, reportable, or critical. Hardware conditions that were unexpected and/or determined to be reportable or critical were evaluated by the applicable CPT and tracked through the PFAR system.

  10. Postflight hardware evaluation 360T026 (RSRM-26, STS-47)

    NASA Astrophysics Data System (ADS)

    Nielson, Greg

    1993-05-01

    The final report for the Clearfield disassembly evaluation and a continuation of the KSC postflight assessment for the 360T026 (STS-47) Redesigned Solid Rocket Motor (RSRM) flight set is provided. All observed hardware conditions were documented on PFOR's and are included in Appendices A, B, and C. Appendices D and E contain the measurements and safety factor data for the nozzle and insulation components. This report, along with the KSC Ten-Day Postflight Hardware Evaluation Report (TWR-64203), represents a summary of the 360T026 hardware evaluation. The as-flown hardware configuration is documented in TWR-60472. Disassembly evaluation photograph numbers are logged in TWA-1987. The 360T026 flight set disassembly evaluations described were performed at the RSRM Refurbishment Facility in Clearfield, Utah. The final factory joint demate occurred on 12 April 1993. Detailed evaluations were performed in accordance with the Clearfield Postflight Engineering Evaluation Plan (PEEP), TWR-50051, Revision A. All observations were compared against limits that are also defined in the PEEP. These limits outline the criteria for categorizing the observations as acceptable, reportable, or critical. Hardware conditions that were unexpected and/or determined to be reportable or critical were evaluated by the applicable CPT and tracked through the PFAR system.

  11. Postflight hardware evaluation (RSRM-29, STS-54)

    NASA Astrophysics Data System (ADS)

    1993-09-01

    This document is the final report for the Clearfield disassembly evaluation and a continuation of the KSC postflight assessment for the RSRM-29 flight set. All observed hardware conditions were documented on PFOR's and are included in Appendices A, B, and C. Appendices D and E contain the measurements and safety factor data for the nozzle and insulation components. This report, along with the KSC Ten-Day Postflight Hardware Evaluation Report (TWR-64221), represents a summary of the RSRM-29 hardware evaluation. Disassembly evaluation photograph numbers are logged in TWA-1990. The RSRM-29 flight set disassembly evaluations described in this document were performed at the RSRM Refurbishment Facility in Clearfield, Utah. The final factory joint demate occurred on September 9, 1993. Detailed evaluations were performed in accordance with the Clearfield PEEP, TWR-50051, Revision A. All observations were compared against limits that are also defined in the PEEP. These limits outline the criteria for categorizing the observations as acceptable, reportable, or critical. Hardware conditions that were unexpected and/or determined to be reportable or critical were evaluated by the applicable CPT and tracked through the PFAR system.

  12. Fluorescent supramolecular micelles for imaging-guided cancer therapy.

    PubMed

    Sun, Mengmeng; Yin, Wenyan; Dong, Xinghua; Yang, Wantai; Zhao, Yuliang; Yin, Meizhen

    2016-03-01

    A novel smart fluorescent drug delivery system composed of a perylene diimide (PDI) core and block copolymer poly(d,l-lactide)-b-poly(ethyl ethylene phosphate) is developed and named as PDI-star-(PLA-b-PEEP)8. The biodegradable PDI-star-(PLA-b-PEEP)8 is a unimolecular micelle and can self-assemble into supramolecular micelles, called as fluorescent supramolecular micelles (FSMs), in aqueous media. An insoluble drug camptothecin (CPT) can be effectively loaded into the FSMs and exhibits pH-responsive release. Moreover, the FSMs with good biocompatibility can also be employed as a remarkable fluorescent probe for cell labelling because the maximum emission of PDI is beneficial for bio-imaging. The flow cytometry and confocal laser scanning microscopy analysis demonstrate that the micelles are easily endocytosed by cancer cells. In vitro and in vivo tumor growth-inhibitory studies reveal a better therapeutic effect of FSMs after CPT encapsulation when compared with the free CPT drug. The multifunctional FSM nanomedicine platform as a nanovehicle has great potential for fluorescence imaging-guided cancer therapy. PMID:26881415

  13. High frequency oscillatory ventilation and prone positioning in a porcine model of lavage-induced acute lung injury

    PubMed Central

    Brederlau, Joerg; Muellenbach, Ralf; Kredel, Markus; Greim, Clemens; Roewer, Norbert

    2006-01-01

    Background This animal study was conducted to assess the combined effects of high frequency oscillatory ventilation (HFOV) and prone positioning on pulmonary gas exchange and hemodynamics. Methods Saline lung lavage was performed in 14 healthy pigs (54 ± 3.1 kg, mean ± SD) until the arterial oxygen partial pressure (PaO2) decreased to 55 ± 7 mmHg. The animals were ventilated in the pressure controlled mode (PCV) with a positive endexpiratory pressure (PEEP) of 5 cmH2O and a tidal volume (VT) of 6 ml/kg body weight. After a stabilisation period of 60 minutes, the animals were randomly assigned to 2 groups. Group 1: HFOV in supine position; group 2: HFOV in prone position. After evaluation of prone positioning in group 2, the mean airway pressure (Pmean) was increased by 3 cmH2O from 16 to 34 cmH2O every 20 minutes in both groups accompanied by measurements of respiratory and hemodynamic variables. Finally all animals were ventilated supine with PCV, PEEP = 5 cm H2O, VT = 6 ml/kg. Results Combination of HFOV with prone positioning improves oxygenation and results in normalisation of cardiac output and considerable reduction of pulmonary shunt fraction at a significant (p < 0.05) lower Pmean than HFOV and supine positioning. Conclusion If ventilator induced lung injury is ameliorated by a lower Pmean, a combined treatment approach using HFOV and prone positioning might result in further lung protection. PMID:16584548

  14. Final postflight hardware evaluation report RSRM-28 (STS-53)

    NASA Technical Reports Server (NTRS)

    Starrett, William David, Jr.

    1993-01-01

    The final report for the Clearfield disassembly evaluation and a continuation of the KSC postflight assessment for the RSRM-28 (STS-53) RSRM flight set is presented. All observed hardware conditions were documented on PFOR's and are included in Appendices A through C. Appendices D and E contain the measurements and safety factor data for the nozzle and insulation components. This report, along with the KSC Ten-Day Postflight Hardware Evaluation Report (TWR-64215), represents a summary of the RSRM-28 hardware evaluation. The as-flown hardware configuration is documented in TWR-63638. Disassembly evaluation photograph numbers are logged in TWA-1989. The RSRM-28 flight set disassembly evaluations described were performed at the RSRM Refurbishment Facility in Clearfield, Utah. The final factory joint demate occurred on July 15, 1993. Additional time was required to perform the evaluation of the stiffener rings per special issue 4.1.5.2 because of the washout schedule. The release of this report was after completion of all special issues per program management direction. Detailed evaluations were performed in accordance with the Clearfield PEEP, TWR-50051, Revision A. All observations were compared against limits that are also defined in the PEEP. These limits outline the criteria for categorizing the observations as acceptable, reportable, or critical. Hardware conditions that were unexpected and/or determined to be reportable or critical were evaluated by the applicable team and tracked through the PFAR system.

  15. Combined Negative- and Positive-Pressure Ventilation for the Treatment of ARDS

    PubMed Central

    Raymondos, Konstantinos; Ahrens, Jörg; Molitoris, Ulrich

    2015-01-01

    Objective. Tracheal intubation and positive-pressure ventilation as the current standard of care for the adult respiratory distress syndrome (ARDS) seem to have reached their limit in terms of a further relevant reduction of the still very high mortality. Case Presentation. A 75-year-old male patient developed ARDS after abscess drainage with deteriorating oxygenation, despite positive end-expiratory pressure (PEEP) values above 15 cm H2O. We applied external negative-pressure ventilation with a chamber respirator using −33 cm H2O at inspiration and −15 cm H2O at expiration, combined with conventional pressure support using a PEEP of about 8 cm H2O and a pressure support of 4–12 cm H2O. Alveolar infiltrates disappeared rapidly and PaO2/FiO2 values surpassed 300 mmHg after the first application and 500 mmHg after the second. Negative-pressure ventilation was used for 6–18 hours/day over five days. Now, 13 years later, the patient is still alive and has a good quality of life. Conclusion. Using this or similar concepts, not only in intubated patients but also as a noninvasive approach in patients with ARDS, offers new options that may genuinely differ from the present therapeutic approaches and may, therefore, have the potential to decrease the present high mortality from ARDS. PMID:26290758

  16. Volumetric capnography in the mechanically ventilated patient.

    PubMed

    Blanch, L; Romero, P V; Lucangelo, U

    2006-06-01

    Expiratory capnogram provides qualitative information on the waveform patterns associated with mechanical ventilation and quantitative estimation of expired CO2. Volumetric capnography simultaneously measures expired CO2 and tidal volume and allows identification of CO2 from 3 sequential lung compartments: apparatus and anatomic dead space, from progressive emptying of alveoli and alveolar gas. Lung heterogeneity creates regional differences in CO2 concentration and sequential emptying contributes to the rise of the alveolar plateau and to the steeper the expired CO2 slope. The concept of dead space accounts for those lung areas that are ventilated but not perfused. In patients with sudden pulmonary vascular occlusion due to pulmonary embolism, the resultant high V/Q mismatch produces an increase in alveolar dead space. Calculations derived from volumetric capnography are useful to suspect pulmonary embolism at the bedside. Alveolar dead space is large in acute lung injury and when the effect of positive end-expiratory pressure (PEEP) is to recruit collapsed lung units resulting in an improvement of oxygenation, alveolar dead space may decrease, whereas PEEP-induced overdistension tends to increase alveolar dead space. Finally, measurement of physiologic dead space and alveolar ejection volume at admission or the trend during the first 48 hours of mechanical ventilation might provide useful information on outcome of critically ill patients with acute lung injury or acute respiratory distress syndrome. PMID:16682932

  17. Nanotoxicity comparison of four amphiphilic polymeric micelles with similar hydrophilic or hydrophobic structure

    PubMed Central

    2013-01-01

    Background Nanocarriers represent an attractive means of drug delivery, but their biosafety must be established before their use in clinical research. Objectives Four kinds of amphiphilic polymeric (PEG-PG-PCL, PEEP-PCL, PEG-PCL and PEG-DSPE) micelles with similar hydrophilic or hydrophobic structure were prepared and their in vitro and in vivo safety were evaluated and compared. Methods In vitro nanotoxicity evaluations included assessments of cell morphology, cell volume, inflammatory effects, cytotoxicity, apoptosis and membrane fluidity. An umbilical vein cell line (Eahy.926) and a kind of macrophages (J774.A1) were used as cell models considering that intravenous route is dominant for micelle delivery systems. In vivo analyses included complete blood count, lymphocyte subset analysis, detection of plasma inflammatory factors and histological observations of major organs after intravenous administration to KM mice. Results All the micelles enhanced inflammatory molecules in J774.A1 cells, likely resulting from the increased ROS levels. PEG-PG-PCL and PEEP-PCL micelles were found to increase the J774.A1 cell volume. This likely correlated with the size of PEG-PG-PCL micelles and the polyphosphoester structure in PEEP-PCL. PEG-DSPE micelles inhibited the growth of Eahy.926 cells via inducing apoptosis. This might relate to the structure of DSPE, which is a type of phospholipid and has good affinity with cell membrane. No evidence was found for cell membrane changes after treatment with these micelles for 24 h. In the in vivo study, during 8 days of 4 time injection, each of the four nanocarriers altered the hematic phase differently without changes in inflammatory factors or pathological changes in target organs. Conclusions These results demonstrate that the micelles investigated exhibit diverse nanotoxicity correlated with their structures, their biosafety is different in different cell model, and there is no in vitro and in vivo correlation found. We believe

  18. Inhaled nitric oxide in acute respiratory distress syndrome with and without septic shock requiring norepinephrine administration: a dose–response study

    PubMed Central

    Mourgeon, Eric; Puybasset, Louis; Law-Koune, Jean-Dominique; Lu, Qin; Abdennour, Lamine; Gallart, Lluis; Malassine, Patrick; Rao, GS Umamaheswara; Cluzel, Philippe; Bennani, Abdelhai; Coriat, Pierre; Rouby, Jean-Jacques

    1997-01-01

    Background: The aim of this prospective study was to assess whether the presence of septic shock could influence the dose response to inhaled nitric oxide (NO) in NO-responding patients with adult respiratory distress syndrome (ARDS). Results: Eight patients with ARDS and without septic shock (PaO2 = 95 ± 16 mmHg, PEEP = 0, FiO2 = 1.0), and eight patients with ARDS and septic shock (PaO2 = 88 ± 11 mmHg, PEEP = 0, FiO2 = 1.0) receiving exclusively norepinephrine were studied. All responded to 15 ppm inhaled NO with an increase in PaO2 of at least 40 mmHg, at FiO2 1.0 and PEEP 10 cmH2O. Inspiratory intratracheal NO concentrations were recorded continuously using a fast response time chemiluminescence apparatus. Seven inspiratory NO concentrations were randomly administered: 0.15, 0.45, 1.5, 4.5, 15, 45 and 150 ppm. In both groups, NO induced a dose-dependent decrease in mean pulmonary artery pressure (MPAP), pulmonary vascular resistance index (PVRI), and venous admixture (QVA/QT), and a dose-dependent increase in PaO2/FiO2 (P ≤ 0.012). Dose-response of MPAP and PVRI were similar in both groups with a plateau effect at 4.5 ppm. Dose-response of PaO2/FiO2 was influenced by the presence of septic shock. No plateau effect was observed in patients with septic shock and PaO2/FiO2 increased by 173 ± 37% at 150 ppm. In patients without septic shock, an 82 ± 26% increase in PaO2/FiO2 was observed with a plateau effect obtained at 15 ppm. In both groups, dose-response curves demonstrated a marked interindividual variability and in five patients pulmonary vascular effect and improvement in arterial oxygenation were dissociated. Conclusion: For similar NOinduced decreases in MPAP and PVRI in both groups, the increase in arterial oxygenation was more marked in patients with septic shock. PMID:11056694

  19. Effects of Xuanbai Chengqi decoction on lung compliance for patients with exogenous pulmonary acute respiratory distress syndrome

    PubMed Central

    Mao, Zhengrong; Wang, Haifeng

    2016-01-01

    Objective To observe the effects of Xuanbai Chengqi decoction on lung compliance for patients with exogenous pulmonary acute respiratory distress syndrome. Subjects and methods A total of 53 patients with exogenous pulmonary acute respiratory distress syndrome, who were admitted to the intensive care unit of the First Affiliated Hospital of Henan University of Traditional Chinese Medicine from March 2009 to February 2013, were selected. They were randomly divided into the treatment group (25 cases) and the control group (28 cases). Both the groups were treated with conventional treatment and lung-protective ventilation strategy; apart from these, enema therapy with Xuanbai Chengqi decoction was given to the treatment group. Meanwhile, static lung compliance, dynamic lung compliance, peak airway pressure, plateau pressure, and positive end-expiratory pressure (PEEP) for patients in both the groups were observed and recorded at 24, 48, and 72 hours after the drug was used. Moreover, variations in the duration of parenteral nutrition, incidence rate of complications, and case fatality rate in patients after treatment were recorded. Results For patients in the treatment group, at 48 and 72 hours after treatment, the static lung compliance and dynamic lung compliance were significantly higher than those in the control group, while plateau pressure, peak airway pressure, and PEEP were significantly lower than those before treatment. At the same time, PEEP for patients in the treatment group at 72 hours after treatment was remarkably lower than that in the control group, showing significant difference (P<0.05). The duration of parenteral nutrition in the treatment group was significantly shorter than that in the control group (P<0.05). Both the incidence rate and the fatality rate of complications, such as abdominal distension and ventilator-associated pneumonia, for patients in the treatment group were distinctly smaller than those in the control group (P<0

  20. Effects of large volume, ice-cold intravenous fluid infusion on respiratory function in cardiac arrest survivors.

    PubMed

    Jacobshagen, Claudius; Pax, Anja; Unsöld, Bernhard W; Seidler, Tim; Schmidt-Schweda, Stephan; Hasenfuss, Gerd; Maier, Lars S

    2009-11-01

    International guidelines for cardiopulmonary resuscitation recommend mild hypothermia (32-34 degrees C) for 12-24h in comatose survivors of cardiac arrest. To induce therapeutic hypothermia a variety of external and intravascular cooling devices are available. A cheap and effective method for inducing hypothermia is the infusion of large volume, ice-cold intravenous fluid. There are concerns regarding the effects of rapid infusion of large volumes of fluid on respiratory function in cardiac arrest survivors. We have retrospectively studied the effects of high volume cold fluid infusion on respiratory function in 52 resuscitated cardiac arrest patients. The target temperature of 32-34 degrees C was achieved after 4.1+/-0.5h (cooling rate 0.48 degrees C/h). During this period 3427+/-210 mL ice-cold fluid was infused. Despite significantly reduced LV-function (EF 35.8+/-2.2%) the respiratory status of these patients did not deteriorate significantly. On intensive care unit admission the mean PaO(2) was 231.4+/-20.6 mmHg at a F(i)O(2) of 0.82+/-0.03 (PaO(2)/F(i)O(2)=290.0+/-24.1) and a PEEP level of 7.14+/-0.31 mbar. Until reaching the target temperature of PEEP level (7.23+/-0.36 mbar). Under these conditions the PaO(2)/F(i)O(2) ratio slightly decreased to 247.5+/-18.5 (P=0.0893). Continuing the saline infusion to achieve a body temperature of 33 degrees C, the F(i)O(2) could be further reduced with unchanged PEEP. The infusion of large volume, ice-cold fluid is an effective and inexpensive method for inducing therapeutic hypothermia. Resuscitation from cardiac arrest is associated with a deterioration in respiratory function. The infusion of large volumes of cold fluid does not cause a statistically significant further deterioration in respiratory function. A larger, randomized and prospective study is required to assess the efficacy and safety of ice-cold fluid infusion for

  1. Physiological Correlation of Airway Pressure and Transpulmonary Pressure Stress Index on Respiratory Mechanics in Acute Respiratory Failure

    PubMed Central

    Pan, Chun; Chen, Lu; Zhang, Yun-Hang; Liu, Wei; Urbino, Rosario; Ranieri, V Marco; Qiu, Hai-Bo; Yang, Yi

    2016-01-01

    Background: Stress index at post-recruitment maneuvers could be a method of positive end-expiratory pressure (PEEP) titration in acute respiratory distress syndrome (ARDS) patients. However, airway pressure (Paw) stress index may not reflect lung mechanics in the patients with high chest wall elastance. This study was to evaluate the Paw stress index on lung mechanics and the correlation between Paw stress index and transpulmonary pressure (PL) stress index in acute respiratory failure (ARF) patients. Methods: Twenty-four ARF patients with mechanical ventilation (MV) were consecutively recruited from July 2011 to April 2013 in Zhongda Hospital, Nanjing, China and Ospedale S. Giovanni Battista-Molinette Hospital, Turin, Italy. All patients underwent MV with volume control (tidal volume 6 ml/kg) for 20 min. PEEP was set according to the ARDSnet study protocol. The patients were divided into two groups according to the chest wall elastance/respiratory system elastance ratio. The high elastance group (H group, n = 14) had a ratio ≥30%, and the low elastance group (L group, n = 10) had a ratio <30%. Respiratory elastance, gas-exchange, Paw stress index, and PL stress index were measured. Student's t-test, regression analysis, and Bland–Altman analysis were used for statistical analysis. Results: Pneumonia was the major cause of respiratory failure (71.0%). Compared with the L group, PEEP was lower in the H group (5.7 ± 1.7 cmH2O vs. 9.0 ± 2.3 cmH2O, P < 0.01). Compared with the H group, lung elastance was higher (20.0 ± 7.8 cmH2O/L vs. 11.6 ± 3.6 cmH2O/L, P < 0.01), and stress was higher in the L group (7.0 ± 1.9 vs. 4.9 ± 1.9, P = 0.02). A linear relationship was observed between the Paw stress index and the PL stress index in H group (R2= 0.56, P < 0.01) and L group (R2= 0.85, P < 0.01). Conclusion: In the ARF patients with MV, Paw stress index can substitute for PL to guide ventilator settings. Trial Registration: ClinicalTrials.gov NCT02196870 (https

  2. Deadly dozen: dealing with the 12 types of thoracic injuries.

    PubMed

    Cipolle, Mark; Rhodes, Michael; Tinkoff, Glen

    2012-09-01

    Although most thoracic trauma may be treated non-operatively, major thoracic trauma accounts for 25% of trauma deaths. Except for provision of a definitive airway and/or relief of a tension pneumothorax with a needle decompression, the vast majority of thoracic trauma is best served with "load and go," high-flow oxygen, placement of an IV line and administration of crystalloid solutions as the clinical scenario would indicate. Understanding the mechanism of injury is helpful in establishing both prehospital and in-hospital management priorities. Patients who sustain a single penetrating wound to the chest have the best survivability after a resuscitative thoracotomy. Practicing chest assessment skills is vital to being a good prehospital provider. Ultrasound, NIRS tissue oxygenation and telemedicine will likely become more commonly employed as prehospital monitoring options. PEEP, or "over bagging," may exacerbate a simple or open pneumothorax, converting it to a tension pneumothorax. PMID:23342703

  3. Autocycling and increase in intrinsic positive end-expiratory pressure during mechanical ventilation.

    PubMed

    Harboe, S; Hjalmarsson, S; Søreide, E

    2001-11-01

    Modern ventilators are complicated electronic instruments with microprocessors and software, with the possibility of technical errors and problems such as autocycling. Despite autocycling being recognized as a problem in textbooks and reviews, there are few reports about autocycling in the literature. We report a case where a sudden increase in respiratory frequency due to autocycling resulted in a dangerous increase in intrinsic positive end-expiratory pressure (intrinsic PEEP, PEEPi). We think our case illustrates that autocycling does occur, but that the exact underlying mechanism may be hard to document and understand for clinicians. To remedy this situation, we suggest that manufacture-independent technical expertise should be established to evaluate incidents and suggest improvements. PMID:11736686

  4. "Yondering" IYA: How the Astronomical Society of the Pacific is Adapting its International Year of Astronomy Programs for the Long Haul

    NASA Astrophysics Data System (ADS)

    Manning, J. G.

    2011-09-01

    The International Year of Astronomy in 2009, the 400th anniversary of the year Galileo peeped at the heavens with his new telescope, is history. But 2010 is the 400th anniversary of the year he published, and we are now into "Beyond IYA" territory, as things developed for or during IYA are adapted for longer-term use as legacy products and programs. The Astronomical Society of the Pacific (ASP) is continuing three of its IYA efforts in this regard. This article describes how the ASP's IYA Discovery Guides (online packages of theme- and object-based educational materials), Cosmic Clearinghouse (a website with a wide variety of links to good educational materials), and Galileo Teacher Training Program (a teacher workshop using Galileo's iconic observations to teach the process of science) are being adapted for ongoing availability "over yonder," well beyond the horizon of IYA.

  5. Acute Eosinophilic Pneumonia: Pyrethroid Exposure & Change In Smoking Habit!

    PubMed

    Kuriakose, Kevin; Klair, Jagpal Singh; Johnsrud, Andrew; Meena, Nikhil K

    2016-06-01

    We report a case of Acute Eosinophilic Pneumonia (AEP) in a 29-year-old white woman with recent use of a'flea bomb' (containing pyrethroids) at home while remaining indoors, about 48 hours prior to presentation, and recent change in smoking habit (restarted 2 weeks prior after quitting for 10 years). She presented with two days of worsening fever, shortness of breath, productive cough, developed hypoxemic respiratory failure and ARDS. She required a PEEP of 20 and 100% FiO2 to maintain oxygenation. Bronchoalveolar lavage showed 36% Eosinophils. She was given IV steroids with dramatic clinical and radiological improvement. To the best of our knowledge, this is the second report associating AEP with pyrethroid exposure. PMID:27434983

  6. A new design for high stability pressure-controlled ventilation for small animal lung imaging

    NASA Astrophysics Data System (ADS)

    Kitchen, M. J.; Habib, A.; Fouras, A.; Dubsky, S.; Lewis, R. A.; Wallace, M. J.; Hooper, S. B.

    2010-02-01

    We have developed a custom-designed ventilator to deliver a stable pressure to the lungs of small animals for use in imaging experiments. Our ventilator was designed with independent pressure vessels to separately control the Peak Inspiratory Pressure (PIP) and Positive End Expiratory Pressure (PEEP) to minimise pressure fluctuations during the ventilation process. The ventilator was computer controlled through a LabVIEW interface, enabling experimental manipulations to be performed remotely whilst simultaneously imaging the lungs in situ. Mechanical ventilation was successfully performed on newborn rabbit pups to assess the most effective ventilation strategies for aerating the lungs at birth. Highly stable pressures enabled reliable respiratory gated acquisition of projection radiographs and a stable prolonged (15 minute) breath-hold for high-resolution computed tomography of deceased rabbit pups at different lung volumes.

  7. [Reexpansion Pulmonary Edema during Emergency Surgery in a Patient with Spontaneous Hemopneumothorax].

    PubMed

    Yamaguchi, Satoshi; Hirakawa, Kei

    2015-06-01

    A 43-year-old male patient with spontaneous hemopneumothorax of the right lung underwent emergency video-assisted thoracoscopic surgery for drainage, hemostasis and bullae resection. Fifteen minutes after reexpansion of the right lung, we found bubbly sputum coming out from the right tracheal tube and cloudy shadow in the right field of his chest X-ray. The occurrence of reexpansion pulmonary edema (RPE) was considered. Subsequent mechanical ventilation with PEEP and administration of steroid and diuretic was done as his treatment. His respiratory state was stabiized in the next two days. As the lung collapse following spontaneous hemopneumothorax often becomes more severe, we should pay attention to the occurrence of RPE after expansion of affected side lung. And, if it occurred, appropriate and prompt treatment as above should be done because of its high mortality. PMID:26437555

  8. Thoracic Block Technique Associated with Positive End-Expiratory Pressure in Reversing Atelectasis

    PubMed Central

    Pereira, Luciana Carnevalli; de Souza Netto, Ana Paula; da Silva, Fernanda Cordeiro; Pereira, Silvana Alves; Moran, Cristiane Aparecida

    2015-01-01

    A preschool four-year-old male patient had been admitted to the Mandaqui Hospital with a diagnosis of lobar pneumonia, pleural effusion, and right lung atelectasis. Treatment consisted of antibiotics and physiotherapy sessions, using a technique described in the literature as Insufflation Technique to Reverse Atelectasis (ITRA), which consists of a thoracic block of healthy lung tissue, leaving only the atelectasis area free, associated with the use of invasive or noninvasive mechanical ventilation with positive airway pressure for reversal of atelectasis. Two physiotherapy sessions were conducted daily. The sessions lasted 20 minutes and were fractionated into four series of five minutes each. Each series bilateral thoracic block was performed for 20 seconds with a pause lasting for the same time. Associated with the thoracic block, a continuous positive airways pressure was used using a facial mask and 7 cm H2O PEEP provided via CPAP. Conclusion. ITRA technique was effective in reversing atelectasis in this patient. PMID:25883824

  9. Measurement of pressure-volume curves in patients on mechanical ventilation: methods and significance

    PubMed Central

    Lu, Qin; Rouby, Jean-Jacques

    2000-01-01

    Physiological background concerning mechanics of the respiratory system, techniques of measurement and clinical implications of pressure-volume curve measurement in mechanically ventilated patients are discussed in the present review. The significance of lower and upper inflection points, the assessment of positive end-expiratory pressure (PEEP)-induced alveolar recruitment and overdistension and rationale for optimizing ventilatory settings in patients with acute lung injury are presented. Evidence suggests that the continuous flow method is a simple and reliable technique for measuring pressure-volume curves at the bedside. In patients with acute respiratory failure, determination of lower and upper inflection points and measurement of respiratory compliance should become a part of the routine assessment of lung injury severity, allowing a bedside monitoring of the evolution of the lung disease and an optimization of mechanical ventilation. PMID:11094498

  10. Postperfusion lung syndrome and related sequelae.

    PubMed

    Yuan, Shi-Min

    2016-05-01

    Postperfusion lung syndrome is a rare but sometimes lethal complication secondary to cardiopulmonary bypass. It often leads to multiorgan failure and mixed acid-base disturbances, thus making a refractory condition. A 69-year-old female, undergoing a successful cardiac lipoma resection under cardiopulmonary bypass, unfortunately developed postperfusion lung syndrome with associated multiorgan failure and triple acid-base disturbances (TABDs). Her condition deteriorated rapidly on postoperative day three and became moribund. This article reports a rare association following a surgical resection of cardiac lipoma, complicated with postperfusion lung syndrome and high-anion-gap and hyperchloride TABDs. It is recommended that proper positive end-expiratory pressure (PEEP) (5-10 cmH2O) with low tidal volume (6 mL/kg) be applied in order to minimize the compromise to cardiac function of cardiac surgical patients. PMID:27162696

  11. Should a Portable Ventilator Be Used in All In-Hospital Transports?

    PubMed

    Holets, Steven R; Davies, John D

    2016-06-01

    Movement of the mechanically ventilated patient may be for a routine procedure or medical emergency. The risks of transport seem manageable, but the memory of a respiratory-related catastrophe still gives many practitioners pause. The risk/benefit ratio of transport must be assessed before movement. During transport of the ventilated patients, should we always use a transport ventilator? What is the risk of using manual ventilation? How are PEEP and FIO2 altered? Is there an impact on the ability to trigger during manual ventilation? Is hyperventilation and hypoventilation a common problem? Does hyperventilation or hypoventilation result in complications? Are portable ventilators worth the cost? What about the function of portable ventilators? Can these devices faithfully reproduce ICU ventilator function? The following pro and con discussion will attempt to address many of these issues by reviewing the current evidence on transport ventilation. PMID:27235317

  12. The hydrodynamics of a moving fluid-liquid contact line

    NASA Astrophysics Data System (ADS)

    Vanderzanden, Antonius Johannus J.

    The hydrodynamics associated with an advancing contact line, where a viscous liquid displaces a fluid with a negligible viscosity, is examined. A model is proposed which approximates the shape of an advancing meniscus in a tube or between parallel plates. Comparison of the predictions of the model with available numerical and experimental results provides an indication of its reliability. This model is applied to receding contact lines, where a viscous liquid is displaced by a fluid of negligible viscosity. The model is extended to examine moving liquid-liquid contact lines where the viscosity of neither fluid can be neglected. Experiments concerning the macroscopic shape of a meniscus in a tube and experiments which lay claim to be able to peep into the microscopic region close to the contact line not accessible with the naked eye are presented.

  13. Isolated particle swarm optimization with particle migration and global best adoption

    NASA Astrophysics Data System (ADS)

    Tsai, Hsing-Chih; Tyan, Yaw-Yauan; Wu, Yun-Wu; Lin, Yong-Huang

    2012-12-01

    Isolated particle swarm optimization (IPSO) segregates particles into several sub-swarms in order to improve the ability of the global optimization. In this study, particle migration and global best adoption (gbest adoption) are used to improve IPSO. Particle migration allows particles to travel among sub-swarms, based on the fitness of the sub-swarms. The use of gbest adoption allows sub-swarms to peep at the gbest proportionally or probably after a certain number of iterations, i.e. gbest replacing, and gbest sharing, respectively. Three well-known benchmark functions are utilized to determine the parameter settings of the IPSO. Then, 13 benchmark functions are used to study the performance of the designed IPSO. Computational experience demonstrates that the designed IPSO is superior to the original version of particle swarm optimization (PSO) in terms of the accuracy and stability of the results, when isolation phenomenon, particle migration and gbest sharing are involved.

  14. A Dedicated Z-Stent for Acquired Saber-Sheath Tracheobronchomalacia

    SciTech Connect

    Kishi, Kazushi; Fujimoto, Hisashi Kobayashi; Sonomura, Tetsuo; Uetani, Kosaku; Nishida, Norifumi; Ohata, Masahiro; Sato, Morio; Yamada, Ryusaku

    1997-11-15

    The tracheobronchial lumen has a continuous horseshoe arch morphology. We formed Z-stents accordingly to support the weakened cartilagenous portions. With this type of stent we treated a patient with acquired saber-sheath type tracheobronchomalacia (TBM), Rayl's type II, Johnson's grade III, whose condition was aggravated even under positive end expiratory pressure (PEEP) therapy. The patient improved gradually. No immediate complication was observed. Bronchofiberscopic examination revealed that the tracheobronchial arcade was closely strut-braced and showed no expiratory collapse. Six months later, when the patient was intubated due to asthmatic attacks, tissue ingrowth through the stent was found and removed. There was no recurrence of TBM. The patient died 2 years later of pneumoconiosis.

  15. Assessment of Single-Word Production for Children under Three Years of Age: Comparison of Children with and without Cleft Palate

    PubMed Central

    Scherer, Nancy J.; Williams, Lynn; Stoel-Gammon, Carol; Kaiser, Ann

    2012-01-01

    Background. This study reports comparative phonological assessment results for children with cleft lip and/or palate (CLP) to typically developing peers using an evaluation tool for early phonological skills. Methods. Children without clefts (NC = noncleft) and 24 children with CLP, ages of 18–36 months, were evaluated using the Profile of Early Expressive Phonological Skills (PEEPSs) [1]. Children interacted with toy manipulatives to elicit a representative sample of target English consonants and syllable structures that are typically acquired by children between 18 and 27 months of age. Results. Results revealed significant differences between the two groups with regard to measures of consonant inventory, place of articulation, manner of production, accuracy, and error patterns. Syllable structure did not indicate differences, with the exception of initial consonant clusters. Conclusions. findings provide support for PEEPS as a viable option for single-word assessment of children with CLP prior to 3 years of age. PMID:22611404

  16. [Implementation of modern trends in the methods of the ventilation support in the new apparatus for artificial lung ventilation Avenir-221 P].

    PubMed

    Gal'perin, Iu Sh; Alkhimova, L R; Dmitriev, N D; Kozlova, I A; Nemirovskiĭ, S B; Makarov, M V; Safronov, A Iu

    2005-01-01

    In the new ventilator Avenir-221 P modern lines of development of ventilation support in intensive therapy of adults and children are implemented. The capacities of the ventilator are successfully combined with its technical decisions which include microprocessor parametrical controlling, programming-controlled electric drive, an information saturation, intuitively clear control system, protection against interruption of power supply sources and oxygen feeding falls. A set of functional characteristics (modes VCV, PCV, Ass/Contr, PSV, SIMV, PEEP, Sigh, etc.) in combination with an original design make the device the most accessible and promising for application in intensive care and resuscitation units of a wide network of Russian hospitals and clinics. The ventilator Avenir-221 P has passed all required tests and is presently commercially available. PMID:16491658

  17. Intraoperative mechanical ventilation strategies for one-lung ventilation.

    PubMed

    Şentürk, Mert; Slinger, Peter; Cohen, Edmond

    2015-09-01

    One-lung ventilation (OLV) has two major challenges: oxygenation and lung protection. The former is mainly because the ventilation of one lung is stopped while the perfusion continues; the latter is mainly because the whole ventilation is applied to only one lung. Recommendations for maintaining the oxygenation and methods of lung protection can contradict each other (such as high vs. low inspiratory oxygen fraction (FiO2), high vs. low tidal volume (TV), etc.). In light of the (very few) randomized clinical trials, this review focuses on a recent strategy for OLV, which includes a possible decrease in FiO2, lower TVs, positive end-expiratory pressure (PEEP) to the dependent lung, continuous positive airway pressure (CPAP) to the non-dependent lung and recruitment manoeuvres. Other applications such as anaesthetic choice and fluid management can affect the success of ventilatory strategy; new developments have changed the classical approach in this respect. PMID:26643100

  18. Post- Thyroidectomy Haematoma Causing Severe Supraglottic Oedema and Pulmonary Oedema - A Case Report

    PubMed Central

    Pujari, Vinayak Seenappa; Anandaswamy, Tejesh C; Vig, Saurabh

    2014-01-01

    Large, long standing goiters present multiple challenges to anaesthesiologist. Post thyroidectomy haematoma is a rare but life threatening complication of thyroid surgery leading to airway obstruction. We report a case of huge goiter that underwent near total thyroidectomy and developed post thyroidectomy haematoma. Within no time it resulted in near fatal airway obstruction, pulmonary oedema and cardiac arrest. The haematoma was evacuated immediately and patient was resuscitated successfully. Pulmonary oedema was further worsened by subsequent aggressive fluid resuscitation. She was electively ventilated with PEEP and was extubated after five days. Except for right vocal cord palsy her postoperative stay was uneventful. This is unique case where a post thyoidectomy haematoma has resulted in fatal supraglottic oedema and pulmonary oedema. Early recognition, immediate intubation and evacuation of haematoma are the key to manage this complication. We highlight on the pathophysiology of haematoma and discuss the strategies to prevent similar events in future. PMID:25300409

  19. Postperfusion lung syndrome and related sequelae

    PubMed Central

    2016-01-01

    Postperfusion lung syndrome is a rare but sometimes lethal complication secondary to cardiopulmonary bypass. It often leads to multiorgan failure and mixed acid-base disturbances, thus making a refractory condition. A 69-year-old female, undergoing a successful cardiac lipoma resection under cardiopulmonary bypass, unfortunately developed postperfusion lung syndrome with associated multiorgan failure and triple acid-base disturbances (TABDs). Her condition deteriorated rapidly on postoperative day three and became moribund. This article reports a rare association following a surgical resection of cardiac lipoma, complicated with postperfusion lung syndrome and high-anion-gap and hyperchloride TABDs. It is recommended that proper positive end-expiratory pressure (PEEP) (5–10 cmH2O) with low tidal volume (6 mL/kg) be applied in order to minimize the compromise to cardiac function of cardiac surgical patients. PMID:27162696

  20. Wound complications after median sternotomy: A study of 61 patients from a consecutive series of 9,279

    PubMed Central

    Ott, David A.; Cooley, Denton A.; Solis, Robert T.; Harrison, Clanton B.

    1980-01-01

    Among a consecutive series of 9,279 sternotomies performed during a period of 2½ years, 61 (0.66%) patients developed significant wound complications. Of these, 58 (95.1%) survived. Sternal infection occurred in 36 patients (0.39%). Predisposing factors included chronic obstructive pulmonary disease, diabetes mellitus, obesity, closed chest massage, prolonged assisted ventilation, and excessive bleeding after operation. Positive end expiratory pressure (PEEP) did not, in itself, predispose to sternal dehiscence. Intermittent positive pressure breathing (IPPB) treatments caused excessive coughing, which may have increased the likelihood of dehiscence. Disposable drapes and expeditious surgery probably contributed to the low incidence of wound infection. Early diagnosis, surgical debridement, rewiring and primary closure with substernal drainage, without continuous antibiotic irrigation, resulted in satisfactory resolution in most patients. PMID:15216289

  1. Non-standard Space Weather Products and Services from NOAA

    NASA Astrophysics Data System (ADS)

    Denig, W. F.; Viereck, R. A.

    2012-12-01

    The NOAA National Geophysical Data Center (NGDC) and Space Weather Prediction Center (SWPC) have developed and are continuing to develop a variety of "non-standard" data products for near real-time space weather applications. Core space weather services provided by SWPC include access to space environmental data from NOAA operational satellites and leveraged data from NASA and USAF assets. Core services also include operational space weather model results providing environmental specifications and forecasts. Non-standard products to be discussed include space weather services and applications that have either not yet reached operational maturity or are being released as beta-version test products. Included are the Forecasting Ionospheric Real-time Scintillation Tool (FIRST), the Ovation Prime Real-Time product, the Space Environment Anomaly Expert System Real Time (SEAESRT) and the PEople Empowered Product (PEEP). The status of these products, including how to access and provide comments, will be presented.

  2. Effect of 2-aminoadamantane derivatives on behavior of mice in a modified light/dark test.

    PubMed

    Avgustinovich, D F; Fomina, M K; Suslov, E V; Tolstikova, T G; Volcho, K P; Salakhutdinov, N F

    2014-12-01

    The effects of two derivatives of 2-aminoadamantane, enantiomers J447H and J579, on the behavior of male and female C57Bl/6J mice were studied using a modified light/dark test. The substances differed by their effects on the behavior of male mice. J579 reduced the number of rearings. J447H in a dose of 1 mg/kg affected more parameters: it reduced exploratory activity 1 h after administration and stimulated exploratory and motor activity in 2 h. In female mice, J447H significantly reduced the number of peepings into holes in 2 h after administration. The results indicate that further analysis of the effects of J579 and especially J447H is required. PMID:25430650

  3. [Respiratory care with prone position for diffuse atelectasis in critically ill patients].

    PubMed

    Shichinohe, Y; Ujike, Y; Kurihara, M; Yamamoto, S; Oota, K; Tsukamoto, M; Imaizumi, H; Kaneko, M

    1991-01-01

    Diffuse atelectasis often occurs in the dorsal region of the lung of critically ill patients under long term mechanical ventilation. Conventional physical therapies (ex. PEEP, Sigh) have little effect on diffuse dorsal atelectasis. We provided respiratory care with prone position for 7 patients with severe respiratory distress (Two patients were treated twice). Improvement of their Respiratory Indexes (RI, mean 2.97) was obtained in the prone position for 6-163 (mean 35.8) hours. Ventilation efficiency also improved. Static lung compliance didn't change. It was assumed that the prone position was the factor responsible for the improvement of pulmonary V/Q ratio, the change of movement pattern of the diaphragm, and the ease of postural drainage of sputum. There were no complications. We conclude that prone position respiratory care has high utility for critically ill patients with diffuse dorsal atelectasis. PMID:2024073

  4. Sustained Inflation at Birth Did Not Alter Lung Injury from Mechanical Ventilation in Surfactant-Treated Fetal Lambs

    PubMed Central

    Hillman, Noah H.; Kemp, Matthew W.; Miura, Yuichiro; Kallapur, Suhas G.; Jobe, Alan H.

    2014-01-01

    Background Sustained inflations (SI) are used with the initiation of ventilation at birth to rapidly recruit functional residual capacity and may decrease lung injury and the need for mechanical ventilation in preterm infants. However, a 20 second SI in surfactant-deficient preterm lambs caused an acute phase injury response without decreasing lung injury from subsequent mechanical ventilation. Hypothesis A 20 second SI at birth will decrease lung injury from mechanical ventilation in surfactant-treated preterm fetal lambs. Methods The head and chest of fetal sheep at 126±1 day GA were exteriorized, with tracheostomy and removal of fetal lung fluid prior to treatment with surfactant (300 mg in 15 ml saline). Fetal lambs were randomized to one of four 15 minute interventions: 1) PEEP 8 cmH2O; 2) 20 sec SI at 40 cmH2O, then PEEP 8 cmH2O; 3) mechanical ventilation with 7 ml/kg tidal volume; or 4) 20 sec SI then mechanical ventilation at 7 ml/kg. Fetal lambs remained on placental support for the intervention and for 30 min after the intervention. Results SI recruited a mean volume of 6.8±0.8 mL/kg. SI did not alter respiratory physiology during mechanical ventilation. Heat shock protein (HSP) 70, HSP60, and total protein in lung fluid similarly increased in both ventilation groups. Modest pro-inflammatory cytokine and acute phase responses, with or without SI, were similar with ventilation. SI alone did not increase markers of injury. Conclusion In surfactant treated fetal lambs, a 20 sec SI did not alter ventilation physiology or markers of lung injury from mechanical ventilation. PMID:25419969

  5. Aging-related changes in respiratory system mechanics and morphometry in mice.

    PubMed

    Elliott, Jonathan E; Mantilla, Carlos B; Pabelick, Christina M; Roden, Anja C; Sieck, Gary C

    2016-07-01

    Previous work investigating respiratory system mechanics in mice has reported an aging-related increase in compliance and mean linear intercept (Lm). However, these changes were assessed using only a young (2-mo-old) and old (20- and 26-mo-old) group yet were interpreted to reflect a linear evolution across the life span. Therefore, to investigate respiratory system mechanics and lung morphometry across a more complete spectrum of ages, we utilized 2 (100% survival, n = 6)-, 6 (100% survival, n = 12)-, 18 (90% survival, n = 12)-, 24 (75% survival, n = 12)-, and 30 (25% survival, n = 12)-mo-old C57BL/6 mice. We found a nonlinear aging-related decrease in respiratory system resistance and increase in dynamic compliance and hysteresis between 2- and 24-mo-old mice. However, in 30-mo-old mice, respiratory system resistance increased, and dynamic compliance and hysteresis decreased relative to 24-mo-old mice. Respiratory system impedance spectra were measured between 1-20.5 Hz at positive end-expiratory pressures (PEEP) of 1, 3, 5, and 7 cmH2O. Respiratory system resistance and reactance at each level of PEEP were increased and decreased, respectively, only in 2-mo-old animals. No differences in the respiratory system impedance spectra were observed in 6-, 18-, 24-, and 30-mo-old mice. Additionally, lungs were fixed following tracheal instillation of 4% paraformaldehyde at 25 cmH2O and processed for Lm and airway collagen deposition. There was an aging-related increase in Lm consistent with emphysematous-like changes and no evidence of increased airway collagen deposition. Accordingly, we demonstrate nonlinear aging-related changes in lung mechanics and morphometry in C57BL/6 mice. PMID:27288490

  6. Quantification of asymmetric lung pathophysiology as a guide to the use of simultaneous independent lung ventilation in posttraumatic and septic adult respiratory distress syndrome.

    PubMed Central

    Siegel, J H; Stoklosa, J C; Borg, U; Wiles, C E; Sganga, G; Geisler, F H; Belzberg, H; Wedel, S; Blevins, S; Goh, K C

    1985-01-01

    The management of impaired respiratory gas exchange in patients with nonuniform posttraumatic and septic adult respiratory distress syndrome (ARDS) contains its own therapeutic paradox, since the need for volume-controlled ventilation and PEEP in the lung with the most reduced compliance increases pulmonary barotrauma to the better lung. A computer-based system has been developed by which respiratory pressure-flow-volume relations and gas exchange characteristics can be obtained and respiratory dynamic and static compliance curves computed and displayed for each lung, as a means of evaluating the effectiveness of ventilation therapy in ARDS. Using these techniques, eight patients with asymmetrical posttraumatic or septic ARDS, or both, have been managed using simultaneous independent lung ventilation (SILV). The computer assessment technique allows quantification of the nonuniform ARDS pattern between the two lungs. This enabled SILV to be utilized using two synchronized servo-ventilators at different pressure-flow-volumes, inspiratory/expiratory ratios, and PEEP settings to optimize the ventilatory volumes and gas exchange of each lung, without inducing excess barotrauma in the better lung. In the patients with nonuniform ARDS, conventional ventilation was not effective in reducing shunt (QS/QT) or in permitting a lower FIO2 to be used for maintenance of an acceptable PaO2. SILV reduced per cent v-a shunt and permitted a higher PaO2 at lower FIO2. Also, there was x-ray evidence of ARDS improvement in the poorer lung. While the ultimate outcome was largely dependent on the patient's injury and the adequacy of the septic host defense, by utilizing the SILV technique to match the quantitative aspects of respiratory dysfunction in each lung at specific times in the clinical course, it was possible to optimize gas exchange, to reduce barotrauma, and often to reverse apparently fixed ARDS changes. In some instances, this type of physiologically directed ventilatory

  7. Open lung ventilation in neurosurgery: an update on brain tissue oxygenation.

    PubMed

    Wolf, S; Plev, D V; Trost, H A; Lumenta, C B

    2005-01-01

    Recently, we showed the feasibility of ventilating neurosurgical patients with acute intracranial pathology and concomitant acute respiratory distress syndrome (ARDS) according the so-called Open Lung approach. This technique consists of low tidal volume, elevated positive expiratory pressure (PEEP) level and initial recruitment maneuvers to open up collapsed alveoli. In this report, we focus on our experience to guide recruitment with brain tissue oxygenation (pbrO2) probes. We studied recruitment maneuvers in thirteen patients with ARDS and acute brain injury such as subarachnoid hemorrhage and traumatic brain injury. A pbrO2 probe was implanted in brain tissue at risk for hypoxia. Recruitment maneuvers were performed at an inspired oxygen frcation (FiO2) of 1.0 and a PEEP level of 30 40 cmH2O for 40 seconds. The mean FiO2 necessary for normoxemia could be decreased from 0.85 +/- 0.17 before recruitment to 0.55 +/- 0.12 after 24 hours, while mean PbrO2 (24.6 mmHg before recruitment) did not change. At a mean of 17 minutes after the first recruitment maneuver, PbrO2 showed peak a value of 35.6 +/- 16.6 mmHg, reflecting improvement in arterial oxygenation at an FiO2 of 1.0. Brain tissue oxygenation monitoring provides a useful adjunct to estimate the effects of recruitment maneuvers and ventilator settings in neurosurgical patients with acute lung injury. PMID:16463830

  8. Acute kidney injury in critically ill patients with lung disease: kidney-lung crosstalk

    PubMed Central

    de Abreu, Krasnalhia Lívia Soares; da Silva Junior, Geraldo Bezerra; Muniz, Thalita Diógenes; Barreto, Adller Gonçalves Costa; Lima, Rafael Siqueira Athayde; Holanda, Marcelo Alcântara; Pereira, Eanes Delgado Barros; Libório, Alexandre Braga; Daher, Elizabeth de Francesco

    2013-01-01

    Objective To examine the factors associated with acute kidney injury and outcome in patients with lung disease. Methods A prospective study was conducted with 100 consecutive patients admitted to a respiratory intensive care unit in Fortaleza (CE), Brazil. The risk factors for acute kidney injury and mortality were investigated in a group of patients with lung diseases. Results The mean age of the study population was 57 years, and 50% were male. The incidence of acute kidney injury was higher in patients with PaO2/FiO2<200 mmHg (54% versus 23.7%; p=0.02). Death was observed in 40 cases and the rate of mortality of the acute kidney injury group was higher (62.8% versus 27.6%; p=0.01). The independent factor that was found to be associated with acute kidney injury was PaO2/FiO2<200 mmHg (p=0.01), and the independent risk factors for death were PEEP at admission (OR: 3.6; 95%CI: 1.3-9.6; p=0.009) and need for hemodialysis (OR: 7.9; 95%CI: 2.2-28.3; p=0.001). Conclusion There was a higher mortality rate in the acute kidney injury group. Increased mortality was associated with mechanical ventilation, high PEEP, urea and need for dialysis. Further studies must be performed to better establish the relationship between kidney and lung injury and its impact on patient outcome. PMID:23917978

  9. Titration of tidal volume and induced hypercapnia in acute respiratory distress syndrome.

    PubMed

    Roupie, E; Dambrosio, M; Servillo, G; Mentec, H; el Atrous, S; Beydon, L; Brun-Buisson, C; Lemaire, F; Brochard, L

    1995-07-01

    Mechanical ventilation may promote overdistension-induced pulmonary lesions in patients with acute respiratory distress syndrome (ARDS). The static pressure-volume (P-V) curve of the respiratory system can be used to determine the lung volume and corresponding static airway pressure at which lung compliance begins to diminish (the upper inflection point, or UIP). This fall in compliance may indicate overdistension of lung units. We prospectively studied 42 patients receiving mechanical ventilation with an FIO2 of 0.5 or more for at least 24 h. According to the Lung Injury Score (LIS), 25 patients were classified as having ARDS (LIS > 2.5), while 17 patients constituted a non-ARDS control group. The P-V curve was obtained every 2 d. Mechanical ventilation initially used standard settings (volume-control mode, a positive end-expiratory pressure [PEEP] adjusted to the lower inflection point on the P-V curve, and a tidal volume [VT] of 10 ml/kg). The end-inspiratory plateau pressure (Pplat) was compared to the UIP, and VT was lowered when the Pplat was above the UIP. In the range of lung volume studied on the P-V curves (up to 1600 ml), a UIP could be shown in only one control patient (at 23 cm H2O). By contrast, a UIP was present on the P-V curve obtained from all patients with ARDS, corresponding to a mean airway pressure of 26 +/- 6 cm H2O, a lung volume of 850 +/- 200 ml above functional residual capacity and 610 +/- 235 ml above PEEP.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7599810

  10. Uneven distribution of ventilation in acute respiratory distress syndrome

    PubMed Central

    Rylander, Christian; Tylén, Ulf; Rossi-Norrlund, Rauni; Herrmann, Peter; Quintel, Michael; Bake, Björn

    2005-01-01

    Introduction The aim of this study was to assess the volume of gas being poorly ventilated or non-ventilated within the lungs of patients treated with mechanical ventilation and suffering from acute respiratory distress syndrome (ARDS). Methods A prospective, descriptive study was performed of 25 sedated and paralysed ARDS patients, mechanically ventilated with a positive end-expiratory pressure (PEEP) of 5 cmH2O in a multidisciplinary intensive care unit of a tertiary university hospital. The volume of poorly ventilated or non-ventilated gas was assumed to correspond to a difference between the ventilated gas volume, determined as the end-expiratory lung volume by rebreathing of sulphur hexafluoride (EELVSF6), and the total gas volume, calculated from computed tomography images in the end-expiratory position (EELVCT). The methods used were validated by similar measurements in 20 healthy subjects in whom no poorly ventilated or non-ventilated gas is expected to be found. Results EELVSF6 was 66% of EELVCT, corresponding to a mean difference of 0.71 litre. EELVSF6 and EELVCT were significantly correlated (r2 = 0.72; P < 0.001). In the healthy subjects, the two methods yielded almost identical results. Conclusion About one-third of the total pulmonary gas volume seems poorly ventilated or non-ventilated in sedated and paralysed ARDS patients when mechanically ventilated with a PEEP of 5 cmH2O. Uneven distribution of ventilation due to airway closure and/or obstruction is likely to be involved. PMID:15774050

  11. Acute respiratory failure induced by mechanical pulmonary ventilation at a peak inspiratory pressure of 40 cmH2O.

    PubMed

    Tsuno, K; Sakanashi, Y; Kishi, Y; Urata, K; Tanoue, T; Higashi, K; Yano, T; Terasaki, H; Morioka, T

    1988-09-01

    The effects of high pressure mechanical pulmonary ventilation at a peak inspiratory pressure of 40 cmH(2)O were studied on the lungs of healthy newborn pigs (14-21 days after birth). Forty percent oxygen in nitrogen was used for ventilation to prevent oxygen intoxication. The control group (6 pigs) was ventilated for 48 hours at a peak inspiratory pressure less than 18 cmH(2)O and a PEEP of 3-5 cmH(2)O with a normal tidal volume, and a respiratory rate of 20 times/min. The control group showed few deleterious changes in the lungs for 48 hours. Eleven newborn pigs were ventilated at a peak inspiratory pressure of 40 cmH(2)O with a PEEP of 3-5 cmH(2)O and a respiratory rate of 20 times/min. To avoid respiratory alkalosis, a dead space was placed in the respiratory circuit, and normocarbia was maintained by adjusting dead space volume. In all cases in the latter group, severe pulmonary impairments, such as abnormal chest roentgenograms, hypoxemia, decreased total static lung compliance, high incidence of pneumothorax, congestive atelectasis, and increased lung weight were found within 48 hours of ventilation. When the pulmonary impairments became manifest, 6 of the 11 newborn pigs were switched to the conventional medical and ventilatory therapies for 3-6 days. However, all of them became ventilator dependent, and severe lung pathology was found at autopsy. These pulmonary insults by high pressure mechanical pulmonary ventilation could be occurring not infrequently in the respiratory management of patients with respiratory failure. PMID:15236077

  12. Histopathologic pulmonary changes from mechanical ventilation at high peak airway pressures.

    PubMed

    Tsuno, K; Miura, K; Takeya, M; Kolobow, T; Morioka, T

    1991-05-01

    We investigated the histopathologic pulmonary changes induced by mechanical pulmonary ventilation (MV) with a high peak airway pressure and a large tidal volume in healthy baby pigs. Eleven animals were mechanically ventilated at a peak inspiratory pressure (PIP) of 40 cm H2O, a respiratory rate (RR) of 20 min-1, a positive end-expiratory pressure (PEEP) of 3 to 5 cm H2O, and an FIO2 of 0.4. High airway pressure MV was terminated in 22 +/- 11 h because of severe hypoxemia in the animals. Five of the baby pigs were killed for gross and light microscope studies. The pulmonary changes consisted of alveolar hemorrhage, alveolar neutrophil infiltration, alveolar macrophage and type II pneumocyte proliferation, interstitial congestion and thickening, interstitial lymphocyte infiltration, emphysematous change, and hyaline membrane formation. Those lesions were similar to that seen in the early stage of the adult respiratory distress syndrome (ARDS). The remaining six animals were treated for 3 to 6 days with conventional respiratory care with appropriate ventilator settings. Prominent organized alveolar exudate in addition to lesions was also found in the five animals. These findings were indistinguishable from the clinical late stage of ARDS. Six control animals were mechanically ventilated at a PIP of less than 18 cm H2O, a RR of 20 min-1, a PEEP of 3 to 5 cm H2O, and an FIO2 of 0.4 for 48 h. They showed no notable changes in lung functions and histopathologic findings. Aggressive MV with a high PIP is often applied to patients with respiratory distress to attain adequate pulmonary gas exchange.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2024823

  13. The effect of low level laser therapy on ventilator-induced lung injury in mice (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Szabari, Margit V.; Miller, Alyssa J.; Hariri, Lida P.; Hamblin, Michael R.; Musch, Guido; Stroh, Helene; Suter, Melissa J.

    2016-03-01

    Although mechanical ventilation (MV) is necessary to support gas exchange in critically ill patients, it can contribute to the development of lung injury and multiple organ dysfunction. It is known that high tidal volume (Vt) MV can cause ventilator-induced lung injury (VILI) in healthy lungs and increase the mortality of patients with Acute Respiratory Distress Syndrome. Low level laser therapy (LLLT) has demonstrated to have anti-inflammatory effects. We investigated whether LLLT could alleviate inflammation from injurious MV in mice. Adult mice were assigned to 2 groups: VILI+LLLT group (3 h of injurious MV: Vt=25-30 ml/kg, respiratory rate (RR)=50/min, positive end-expiratory pressure (PEEP)=0 cmH20, followed by 3 h of protective MV: Vt=9 ml/kg, RR=140/min, PEEP=2 cmH20) and VILI+no LLLT group. LLLT was applied during the first 30 min of the MV (810 nm LED system, 5 J/cm2, 1 cm above the chest). Respiratory impedance was measured in vivo with forced oscillation technique and lung mechanics were calculated by fitting the constant phase model. At the end of the MV, bronchoalveolar lavage (BAL) was performed and inflammatory cells counted. Lungs were removed en-bloc and fixed for histological evaluation. We hypothesize that LLLT can reduce lung injury and inflammation from VILI. This therapy could be translated into clinical practice, where it can potentially improve outcomes in patients requiring mechanical ventilation in the operating room or in the intensive care units.

  14. Hyperoxic Acute Lung Injury

    PubMed Central

    Kallet, Richard H; Matthay, Michael A

    2013-01-01

    Prolonged breathing of very high FIO2 (FIO2 ≥ 0.9) uniformly causes severe hyperoxic acute lung injury (HALI) and, without a reduction of FIO2, is usually fatal. The severity of HALI is directly proportional to PO2 (particularly above 450 mm Hg, or an FIO2 of 0.6) and exposure duration. Hyperoxia produces extraordinary amounts of reactive O2 species that overwhelms natural antioxidant defenses and destroys cellular structures through several pathways. Genetic predisposition has been shown to play an important role in HALI among animals, and some genetics-based epidemiologic research suggests that this may be true for humans as well. Clinically, the risk of HALI likely occurs when FIO2exceeds 0.7, and may become problematic when FIO2 exceeds 0.8 for an extended period of time. Both high-stretch mechanical ventilation and hyperoxia potentiate lung injury and may promote pulmonary infection. During the 1960s, confusion regarding the incidence and relevance of HALI largely reflected such issues as the primitive control of FIO2, the absence of PEEP, and the fact that at the time both ALI and ventilator-induced lung injury were unknown. The advent of PEEP and precise control over FIO2, as well as lung-protective ventilation, and other adjunctive therapies for severe hypoxemia, has greatly reduced the risk of HALI for the vast majority of patients requiring mechanical ventilation in the 21st century. However, a subset of patients with very severe ARDS requiring hyperoxic therapy is at substantial risk for developing HALI, therefore justifying the use of such adjunctive therapies. PMID:23271823

  15. Inflammation and lung maturation from stretch injury in preterm fetal sheep.

    PubMed

    Hillman, Noah H; Polglase, Graeme R; Pillow, J Jane; Saito, Masatoshi; Kallapur, Suhas G; Jobe, Alan H

    2011-02-01

    Mechanical ventilation is a risk factor for the development of bronchopulmonary dysplasia in premature infants. Fifteen minutes of high tidal volume (V(T)) ventilation induces inflammatory cytokine expression in small airways and lung parenchyma within 3 h. Our objective was to describe the temporal progression of cytokine and maturation responses to lung injury in fetal sheep exposed to a defined 15-min stretch injury. After maternal anesthesia and hysterotomy, 129-day gestation fetal lambs (n = 7-8/group) had the head and chest exteriorized. Each fetus was intubated, and airway fluid was gently removed. While placental support was maintained, the fetus received ventilation with an escalating V(T) to 15 ml/kg without positive end-expiratory pressure (PEEP) for 15 min using heated, humidified 100% nitrogen. The fetus was then returned to the uterus for 1, 6, or 24 h. Control lambs received a PEEP of 2 cmH(2)O for 15 min. Tissue samples from the lung and systemic organs were evaluated. Stretch injury increased the early response gene Egr-1 and increased expression of pro- and anti-inflammatory cytokines within 1 h. The injury induced granulocyte/macrophage colony-stimulating factor mRNA and matured monocytes to alveolar macrophages by 24 h. The mRNA for the surfactant proteins A, B, and C increased in the lungs by 24 h. The airway epithelium demonstrated dynamic changes in heat shock protein 70 (HSP70) over time. Serum cortisol levels did not increase, and induction of systemic inflammation was minimal. We conclude that a brief period of high V(T) ventilation causes a proinflammatory cascade, a maturation of lung monocytic cells, and an induction of surfactant protein mRNA. PMID:21131401

  16. Hyperpolarized Gas Diffusion MRI for the Study of Atelectasis and Acute Respiratory Distress Syndrome

    PubMed Central

    Cereda, Maurizio; Xin, Yi; Kadlecek, Stephen; Hamedani, Hooman; Rajaei, Jennia; Clapp, Justin; Rizi, Rahim R.

    2014-01-01

    Considerable uncertainty remains about the best ventilator strategies for the mitigation of atelectasis and associated airspace stretch in patients with acute respiratory distress syndrome (ARDS). In addition to several immediate physiological effects, atelectasis increases the risk of ventilator-associated lung injury (VALI), which has been shown to significantly worsen ARDS outcomes. A number of lung imaging techniques have made substantial headway in clarifying the mechanisms of atelectasis. This paper reviews the contributions of CT, PET, and conventional MRI to understanding this phenomenon. In doing so, it also reveals several important shortcomings inherent to each of these approaches. Once these shortcomings have been made apparent, we describe how hyperpolarized gas magnetic resonance imaging (HP MRI)—a technique that is uniquely able to assess responses to mechanical ventilation and lung injury in peripheral airspaces—is poised to fill several of these knowledge gaps. The HP-MRI-derived apparent diffusion coefficient (ADC) quantifies the restriction of 3He diffusion by peripheral airspaces, thereby obtaining pulmonary structural information at an extremely small scale. Lastly, this paper reports the results of a series of experiments that measured ADC in mechanically ventilated rats in order to investigate (i) the effect of atelectasis on ventilated airspaces; (ii) the relationship between positive end-expiratory pressure (PEEP), hysteresis, and the dimensions of peripheral airspaces; and (iii) the ability of PEEP and surfactant to reduce airspace dimensions after lung injury. An increase in ADC was found to be a marker of atelectasis-induced overdistension. With recruitment, higher airway pressures were shown to reduce stretch rather than worsen it. Moving forward, HP MRI has significant potential to shed further light on the atelectatic processes that occur during mechanical ventilation. PMID:24920074

  17. Bank erosion events and processes in the Upper Severn basin

    NASA Astrophysics Data System (ADS)

    Lawler, D. M.; Couperthwaite, J.; Bull, L. J.; Harris, N. M.

    This paper examines river bank retreat rates, individual erosion events, and the processes that drive them in the Upper Severn basin, mid-Wales, UK. Traditional erosion pin networks were used to deliver information on patterns of downstream change in erosion rates. In addition, the novel automatic Photo-Electronic Erosion Pin (PEEP) monitoring system was deployed to generate near-continuous data on the temporal distribution of bank erosion and accretion: this allowed focus on the magnitude and timing of individual erosional and depositional events in relation to specific flow episodes. Erosion dynamics data from throughout the Upper Severn basin are combined with detailed information on bank material properties and spatial change in channel hydraulics derived from direct field survey, to assess the relationships between flow properties and bank erosion rates. Results show that bank erosion rates generally increase downstream, but relate more strongly to discharge than to reach-mean shear stress, which peaks near the basin head. Downstream changes in erosion mechanisms and boundary materials, across the upland/lowland transition (especially the degree of development of composite bank material profiles), are especially significant. Examples of sequences of bank erosion events show how the PEEP system can (a) quantify the impact of individual, rather than aggregated, forcing events, (b) reveal the full complexity of bank response to given driving agents, including delayed erosion events, and (c) establish hypotheses of process-control in bank erosion systems. These findings have important implications for the way in which bank erosion problems are researched and managed. The complex responses demonstrated have special significance for the way in which bank processes and channel-margin sediment injections should be handled in river dynamics models.

  18. Exposure to mechanical ventilation promotes tolerance to ventilator-induced lung injury by Ccl3 downregulation.

    PubMed

    Blázquez-Prieto, Jorge; López-Alonso, Inés; Amado-Rodríguez, Laura; Batalla-Solís, Estefanía; González-López, Adrián; Albaiceta, Guillermo M

    2015-10-15

    Inflammation plays a key role in the development of ventilator-induced lung injury (VILI). Preconditioning with a previous exposure can damp the subsequent inflammatory response. Our objectives were to demonstrate that tolerance to VILI can be induced by previous low-pressure ventilation, and to identify the molecular mechanisms responsible for this phenomenon. Intact 8- to 12-wk-old male CD1 mice were preconditioned with 90 min of noninjurious ventilation [peak pressure 17 cmH2O, positive end-expiratory pressure (PEEP) 2 cmH2O] and extubated. Seven days later, preconditioned mice and intact controls were submitted to injurious ventilation (peak pressure 20 cmH2O, PEEP 0 cmH2O) for 2 h to induce VILI. Preconditioned mice showed lower histological lung injury scores, bronchoalveolar lavage albumin content, and lung neutrophilic infiltration after injurious ventilation, with no differences in Il6 or Il10 expression. Microarray analyses revealed a downregulation of Calcb, Hspa1b, and Ccl3, three genes related to tolerance phenomena, in preconditioned animals. Among the previously identified genes, only Ccl3, which encodes the macrophage inflammatory protein 1 alpha (MIP-1α), showed significant differences between intact and preconditioned mice after high-pressure ventilation. In separate, nonconditioned animals, treatment with BX471, a specific blocker of CCR1 (the main receptor for MIP-1α), decreased lung damage and neutrophilic infiltration caused by high-pressure ventilation. We conclude that previous exposure to noninjurious ventilation induces a state of tolerance to VILI. Downregulation of the chemokine gene Ccl3 could be the mechanism responsible for this effect. PMID:26472813

  19. Clinical evaluation of high-frequency positive-pressure ventilation (HFPPV) in patients scheduled for open-chest surgery.

    PubMed

    Malina, J R; Nordström, S G; Sjöstrand, U H; Wattwil, L M

    1981-05-01

    Comparisons were made in 10 patients scheduled for thoracotomy between a prototype of a low-compressive system (Bronchovent Special) for volume-controlled, high-frequency positive-pressure ventilation (HFPPV; fixed frequency of 60/min; fixed relative insufflation time of 22%), and a conventional respirator (SV-900) for intermittent positive-pressure, volume-controlled ventilation at a frequency of 20/min, after induction of anesthesia, but before surgery. With both ventilator systems intratracheal, intrapleural, systolic, diastolic, and mean arterial systemic and central venous pressures were measured at normoventilation (normocarbia). Mean intratracheal pressure and mean intrapleural pressure were significantly lower with volume-controlled HFPPV (1.3 +/- 0.5 and -4.0 +/- 2.1 (SD) cm H2O, respectively) than with conventional volume-controlled ventilation with SV-900 (2.1 +/- 1.2 and -3.0 +/- 1.5 cm H2O, respectively). No significant differences between the two ventilators were found with respect to arterial systemic and central venous pressures, arterial oxygen and carbon dioxide tensions, or alveolar-arterial oxygen tension difference. With the thorax open, during volume-controlled HFPPV the exposed lung was moderately expanded and exhibited only minor movements during insufflation. Repeated blood gas analyses during surgery showed normocarbia and good oxygenation even during compression of the exposed lung. After compression the lung was readily re-expanded with the aid of a brief period of positive end-expiratory pressure (PEEP). Thus, even relatively low intrapulmonary pressures during volume-controlled HFPPV without PEEP are adequate to keep the open-chest lung expanded during intrathoracic surgery. This creates optimal conditions for the surgeons. PMID:7013568

  20. Indications for manual lung hyperinflation (MHI) in the mechanically ventilated patient with chronic obstructive pulmonary disease.

    PubMed

    Ntoumenopoulos, G

    2005-01-01

    Manual lung hyperinflation (MHI) can enhance secretion clearance, improve total lung/thorax compliance and assist in the resolution of acute atelectasis. To enhance secretion clearance in the intubated patient, the evidence highlights the need to maximize expiratory flow. Chronic pulmonary diseases such as chronic obstructive pulmonary disease (COPD) have often been cited as potential precautions and/or contra-indications to the use of manual lung hyperinflation (MHI). There is an absence of evidence on the effects of MHI in the patient with COPD. Research on the effects of mechanical ventilation in the patient with COPD provides a useful clinical examination of the effect of positive pressure on cardiac and pulmonary function. The potential effects of MHI in the COPD patient group were extrapolated on the basis of the MHI and mechanical ventilation literature. There is the potential for MHI to have both detrimental and beneficial effects on cardiac and pulmonary function in patients with COPD. The potential detrimental effects of MHI may include either, increased intrinsic peep through inadequate time for expiration by the breath delivery rate, tidal volume delivered or through the removal of applied external PEEP thereby causing more dynamic airway compression compromising downward expiratory flow, which may also retard bronchial mucus transport. MHI may also increase right ventricular after load through raised intrathoracic pressures with lung hyperinflation, and may therefore impair right ventricular function in patients with evidence of cor pulmonale. There is the potential for beneficial effects from MHI in the intubated COPD patient group (i.e., secretion clearance), but further research is required, especially on the effect of MHI on inspiratory and expiratory flow rate profiles in this patient group. The more controlled delivery of lung hyperinflation through the use of the mechanical ventilator may be a more optimal means of providing lung hyperinflation

  1. Measuring dead-space in acute lung injury.

    PubMed

    Kallet, R H

    2012-11-01

    Several recent studies have advanced our understanding of dead-space ventilation in patients with acute lung injury/acute respiratory distress syndrome (ALI/ARDS). They have demonstrated the utility of measuring physiologic dead-space-to-tidal volume ratio (VD/VT) and related variables in assessing outcomes as well as therapeutic interventions. These studies have included the evaluation of mortality risk, pulmonary perfusion, as well as the effectiveness of drug therapy, prone positioning, positive end-expiratory pressure (PEEP) titration, and inspiratory pattern in improving gas exchange. In patients with ALI/ARDS managed with lung-protective ventilation a significant relationship between elevated VD/VT and increased mortality continues to be reported in both early and intermediate phases of ALI/ARDS. Some clinical evidence now supports the suggestion that elevated VD/VT in part reflects the severity of pulmonary vascular endothelial damage. Monitoring VD/VT also appears useful in assessing alveolar recruitment when titrating PEEP and may be a particularly expedient method for assessing the effectiveness of prone positioning. It also has revealed how subtle manipulations of inspiratory time and pattern can improve CO(2) excretion. Much of this has been accomplished using volumetric capnography. This allows for more sophisticated measurements of pulmonary gas exchange function including: alveolar VD/VT, the volume of CO(2) excretion and the slope of the alveolar plateau which reflects ventilation: perfusion heterogeneity. Many of these measurements now can be made non-invasively which should only increase the research and clinical utility of volumetric capnography in studying and managing patients with ALI/ARDS. PMID:22858884

  2. A Short Period of Ventilation without Perfusion Seems to Reduce Atelectasis without Harming the Lungs during Ex Vivo Lung Perfusion

    PubMed Central

    Pierre, Leif

    2013-01-01

    To evaluate the lung function of donors after circulatory deaths (DCDs), ex vivo lung perfusion (EVLP) has been shown to be a valuable method. We present modified EVLP where lung atelectasis is removed, while the lung perfusion is temporarily shut down. Twelve pigs were randomized into two groups: modified EVLP and conventional EVLP. When the lungs had reached 37°C in the EVLP circuit, lung perfusion was temporarily shut down in the modified EVLP group, and positive end-expiratory pressure (PEEP) was increased to 10 cm H2O for 10 minutes. In the conventional EVLP group, PEEP was increased to 10 cm H2O for 10 minutes with unchanged lung perfusion. In the modified EVLP group, the arterial oxygen partial pressure (PaO2) was 18.5 ± 7.0 kPa before and 64.5 ± 6.0 kPa after the maneuver (P < 0.001). In the conventional EVLP group, the PaO2 was 16.8 ± 3.1 kPa and 46.8 ± 2.7 kPa after the maneuver (P < 0.01; P < 0.01). In the modified EVLP group, the pulmonary graft weight was unchanged, while in the conventional EVLP group, the pulmonary graft weight was significantly increased. Modified EVLP with normoventilation of the lungs without ongoing lung perfusion for 10 minutes may eliminate atelectasis almost completely without harming the lungs. PMID:24102021

  3. A Short Period of Ventilation without Perfusion Seems to Reduce Atelectasis without Harming the Lungs during Ex Vivo Lung Perfusion.

    PubMed

    Lindstedt, Sandra; Pierre, Leif; Ingemansson, Richard

    2013-01-01

    To evaluate the lung function of donors after circulatory deaths (DCDs), ex vivo lung perfusion (EVLP) has been shown to be a valuable method. We present modified EVLP where lung atelectasis is removed, while the lung perfusion is temporarily shut down. Twelve pigs were randomized into two groups: modified EVLP and conventional EVLP. When the lungs had reached 37°C in the EVLP circuit, lung perfusion was temporarily shut down in the modified EVLP group, and positive end-expiratory pressure (PEEP) was increased to 10 cm H2O for 10 minutes. In the conventional EVLP group, PEEP was increased to 10 cm H2O for 10 minutes with unchanged lung perfusion. In the modified EVLP group, the arterial oxygen partial pressure (PaO2) was 18.5 ± 7.0 kPa before and 64.5 ± 6.0 kPa after the maneuver (P < 0.001). In the conventional EVLP group, the PaO2 was 16.8 ± 3.1 kPa and 46.8 ± 2.7 kPa after the maneuver (P < 0.01; P < 0.01). In the modified EVLP group, the pulmonary graft weight was unchanged, while in the conventional EVLP group, the pulmonary graft weight was significantly increased. Modified EVLP with normoventilation of the lungs without ongoing lung perfusion for 10 minutes may eliminate atelectasis almost completely without harming the lungs. PMID:24102021

  4. Hepatic effects of lung-protective pressure-controlled ventilation and a combination of high-frequency oscillatory ventilation and extracorporeal lung assist in experimental lung injury

    PubMed Central

    Kredel, Markus; Muellenbach, Ralf M.; Johannes, Amélie; Brederlau, Joerg; Roewer, Norbert; Wunder, Christian

    2011-01-01

    Summary Background Ventilation with high positive end-expiratory pressure (PEEP) can lead to hepatic dysfunction. The aim of this study was to investigate the hepatic effects of strategies using high airway pressures either in pressure-controlled ventilation (PCV) or in high-frequency oscillatory ventilation (HFOV) combined with an arteriovenous extracorporeal lung assist (ECLA). Material/Methods Pietrain pigs underwent induction of lung injury by saline lavage. Ventilation was continued for 24 hours either as PCV with tidal volumes of 6 ml/kg and PEEP 3 cmH2O above the lower inflection point of the pressure-volume curve or as HFOV (≥12 Hz) with a mean tracheal airway pressure 3 cmH2O above the lower inflection point combined with arteriovenous ECLA (HFOV+ECLA). Fluids and norepinephrine stabilized the circulation. The indocyanine green plasma disappearance rate, serum bilirubin, aspartate aminotransferase, alanine aminotransferase, γ-glutamyltransferase, alkaline phosphatase, glutamate dehydrogenase, lactate dehydrogenase and creatine kinase were determined repeatedly. Finally, liver neutrophils were counted and liver cell apoptosis was assessed by terminal deoxynucleotidyl transferase nick end labeling (TUNEL). Results Aspartate aminotransferase increased in the PCV group about three-fold and in the HFOV+ECLA group five-fold (p<0.001). Correspondingly, creatine kinase increased about two-fold and four-fold, respectively (p<0.001). Lactate dehydrogenase was increased in the HFOV+ECLA group (p<0.028). The number of neutrophils infiltrating the liver tissue and the apoptotic index were low. Conclusions High airway pressure PCV and HFOV with ECLA in the treatment of lavage-induced lung injury in pigs did not cause liver dysfunction or damage. The detected elevation of enzymes might be of extrahepatic origin. PMID:21959601

  5. Alveolar derecruitment and collapse induration as crucial mechanisms in lung injury and fibrosis.

    PubMed

    Lutz, Dennis; Gazdhar, Amiq; Lopez-Rodriguez, Elena; Ruppert, Clemens; Mahavadi, Poornima; Günther, Andreas; Klepetko, Walter; Bates, Jason H; Smith, Bradford; Geiser, Thomas; Ochs, Matthias; Knudsen, Lars

    2015-02-01

    Idiopathic pulmonary fibrosis (IPF) and bleomycin-induced pulmonary fibrosis are associated with surfactant system dysfunction, alveolar collapse (derecruitment), and collapse induration (irreversible collapse). These events play undefined roles in the loss of lung function. The purpose of this study was to quantify how surfactant inactivation, alveolar collapse, and collapse induration lead to degradation of lung function. Design-based stereology and invasive pulmonary function tests were performed 1, 3, 7, and 14 days after intratracheal bleomycin-instillation in rats. The number and size of open alveoli was correlated to mechanical properties. Active surfactant subtypes declined by Day 1, associated with a progressive alveolar derecruitment and a decrease in compliance. Alveolar epithelial damage was more pronounced in closed alveoli compared with ventilated alveoli. Collapse induration occurred on Day 7 and Day 14 as indicated by collapsed alveoli overgrown by a hyperplastic alveolar epithelium. This pathophysiology was also observed for the first time in human IPF lung explants. Before the onset of collapse induration, distal airspaces were easily recruited, and lung elastance could be kept low after recruitment by positive end-expiratory pressure (PEEP). At later time points, the recruitable fraction of the lung was reduced by collapse induration, causing elastance to be elevated at high levels of PEEP. Surfactant inactivation leading to alveolar collapse and subsequent collapse induration might be the primary pathway for the loss of alveoli in this animal model. Loss of alveoli is highly correlated with the degradation of lung function. Our ultrastructural observations suggest that collapse induration is important in human IPF. PMID:25033427

  6. [Acute respiratory distress syndrome].

    PubMed

    Estenssoro, Elisa; Dubin, Arnaldo

    2016-01-01

    Acute respiratory distress syndrome (ARDS) is an acute respiratory failure produced by an inflammatory edema secondary to increased lung capillary permeability. This causes alveolar flooding and subsequently deep hypoxemia, with intrapulmonary shunt as its most important underlying mechanism. Characteristically, this alteration is unresponsive to high FIO2 and only reverses with end-expiratory positive pressure (PEEP). Pulmonary infiltrates on CXR and CT are the hallmark, together with decreased lung compliance. ARDS always occurs within a week of exposition to a precipitating factor; most frequently pneumonia, shock, aspiration of gastric contents, sepsis, and trauma. In CT scan, the disease is frequently inhomogeneous, with gravitational infiltrates coexisting with normal-density areas and also with hyperaerated parenchyma. Mortality is high (30-60%) especially in ARDS associated with septic shock and neurocritical diseases. The cornerstone of therapy lies in the treatment of the underlying cause and in the use mechanical ventilation which, if inappropriately administered, can lead to ventilator-induced lung injury. Tidal volume = 6 ml/kg of ideal body weight to maintain an end-inspiratory (plateau) pressure = 30 cm H2O ("protective ventilation") is the only variable consistently associated with decreased mortality. Moderate-to-high PEEP levels are frequently required to treat hypoxemia, yet no specific level or titration strategy has improved outcomes. Recently, the use of early prone positioning in patients with PaO2/FIO2 = 150 was associated with increased survival. In severely hypoxemic patients, it may be necessary to use adjuvants of mechanical ventilation as recruitment maneuvers, pressure-controlled modes, neuromuscular blocking agents, and extracorporeal-membrane oxygenation. Fluid restriction appears beneficial. PMID:27576283

  7. Lung imaging in rodents using dual energy micro-CT

    NASA Astrophysics Data System (ADS)

    Badea, C. T.; Guo, X.; Clark, D.; Johnston, S. M.; Marshall, C.; Piantadosi, C.

    2012-03-01

    Dual energy CT imaging is expected to play a major role in the diagnostic arena as it provides material decomposition on an elemental basis. The purpose of this work is to investigate the use of dual energy micro-CT for the estimation of vascular, tissue, and air fractions in rodent lungs using a post-reconstruction three-material decomposition method. We have tested our method using both simulations and experimental work. Using simulations, we have estimated the accuracy limits of the decomposition for realistic micro-CT noise levels. Next, we performed experiments involving ex vivo lung imaging in which intact lungs were carefully removed from the thorax, were injected with an iodine-based contrast agent and inflated with air at different volume levels. Finally, we performed in vivo imaging studies in (n=5) C57BL/6 mice using fast prospective respiratory gating in endinspiration and end-expiration for three different levels of positive end-expiratory pressure (PEEP). Prior to imaging, mice were injected with a liposomal blood pool contrast agent. The mean accuracy values were for Air (95.5%), Blood (96%), and Tissue (92.4%). The absolute accuracy in determining all fraction materials was 94.6%. The minimum difference that we could detect in material fractions was 15%. As expected, an increase in PEEP levels for the living mouse resulted in statistically significant increases in air fractions at end-expiration, but no significant changes in end-inspiration. Our method has applicability in preclinical pulmonary studies where various physiological changes can occur as a result of genetic changes, lung disease, or drug effects.

  8. A Comprehensive Review of Prone Position in ARDS.

    PubMed

    Kallet, Richard H

    2015-11-01

    Prone position (PP) has been used since the 1970s to treat severe hypoxemia in patients with ARDS because of its effectiveness at improving gas exchange. Compared with the supine position (SP), placing patients in PP effects a more even tidal volume distribution, in part, by reversing the vertical pleural pressure gradient, which becomes more negative in the dorsal regions. PP also improves resting lung volume in the dorsocaudal regions by reducing the superimposed pressure of both the heart and the abdomen. In contrast, pulmonary perfusion remains preferentially distributed to the dorsal lung regions, thus improving overall alveolar ventilation/perfusion relationships. Moreover, the larger tissue mass suspended from a wider dorsal chest wall effects a more homogeneous distribution of pleural pressures throughout the lung that reduces abnormal strain and stress development. This is believed to ameliorate the severity or development of ventilator-induced lung injury and may partly explain why PP reduces mortality in severe ARDS. Over 40 years of clinical trials have consistently reported improved oxygenation in approximately 70% of subjects with ARDS. Early initiation of PP is more likely to improve oxygenation than initiation during the subacute phase. Maximal oxygenation improvement occurs over a wide time frame ranging from several hours to several days. Meta-analyses of randomized controlled trials suggest that PP provides a survival advantage only in patients with relatively severe ARDS (PaO2 /FIO2 < 150 mm Hg). Moreover, survival is enhanced when patients are managed with a smaller tidal volume (≤ 8 mL/kg), higher PEEP (10-13 cm H2O), and longer duration of PP sessions (> 10-12 h/session). Combining adjunctive therapies (high PEEP, recruitment maneuvers, and inhaled vasodilators) with PP has an additive effect in improving oxygenation and may be particularly helpful in stabilizing gas exchange in very severe ARDS. PMID:26493592

  9. Recurrent Recruitment Manoeuvres Improve Lung Mechanics and Minimize Lung Injury during Mechanical Ventilation of Healthy Mice

    PubMed Central

    Reiss, Lucy Kathleen; Kowallik, Anke; Uhlig, Stefan

    2011-01-01

    Introduction Mechanical ventilation (MV) of mice is increasingly required in experimental studies, but the conditions that allow stable ventilation of mice over several hours have not yet been fully defined. In addition, most previous studies documented vital parameters and lung mechanics only incompletely. The aim of the present study was to establish experimental conditions that keep these parameters within their physiological range over a period of 6 h. For this purpose, we also examined the effects of frequent short recruitment manoeuvres (RM) in healthy mice. Methods Mice were ventilated at low tidal volume VT = 8 mL/kg or high tidal volume VT = 16 mL/kg and a positive end-expiratory pressure (PEEP) of 2 or 6 cmH2O. RM were performed every 5 min, 60 min or not at all. Lung mechanics were followed by the forced oscillation technique. Blood pressure (BP), electrocardiogram (ECG), heart frequency (HF), oxygen saturation and body temperature were monitored. Blood gases, neutrophil-recruitment, microvascular permeability and pro-inflammatory cytokines in bronchoalveolar lavage (BAL) and blood serum as well as histopathology of the lung were examined. Results MV with repetitive RM every 5 min resulted in stable respiratory mechanics. Ventilation without RM worsened lung mechanics due to alveolar collapse, leading to impaired gas exchange. HF and BP were affected by anaesthesia, but not by ventilation. Microvascular permeability was highest in atelectatic lungs, whereas neutrophil-recruitment and structural changes were strongest in lungs ventilated with high tidal volume. The cytokines IL-6 and KC, but neither TNF nor IP-10, were elevated in the BAL and serum of all ventilated mice and were reduced by recurrent RM. Lung mechanics, oxygenation and pulmonary inflammation were improved by increased PEEP. Conclusions Recurrent RM maintain lung mechanics in their physiological range during low tidal volume ventilation of healthy mice by preventing atelectasis and

  10. Fire in Variable Density Wind Tunnel

    NASA Technical Reports Server (NTRS)

    1927-01-01

    Fire gutted interior of Variable-Density Tunnel (VDT). On August 1, 1927 a major fire broke out inside the VDT. Clean-up, repair, redesign and reinstallation of equipment took about 8 months. From the Variable Density Tunnel Log Book: 'Aug. 1. Computation of the previous tests were in progress in the office and the tank had been pumped up to 20 atmospheres and run to equalize the temperatures about 11:25 a.m. The 20 atmosphere run on the M-6 polished air foil was started and two readings had been taken when sparks were seen to pass in the return passage. Mr. Turner yelled 'Fire!' and shut off the drive motor and opened the blow off valve. Through the peep holes it could be seen that the fire had a good start. It soon fogged up inside so that it could no longer be seen. We then waited for the pressure to go down. However, due to the burning inside, the pressure probably continued to rise. We noticed that the blow off pipe was becoming very hot and that smoke was coming out around the propeller shaft. Suddenly (sic) there was a loud bursting noise and every one left the building. This was probably the blowing of the gasket around the blow off valve. Later the top peep hole blew out and the blow off pipe blew out from the valve. The pressure then began to go down and we returned. The building was full of smoke. When the pressure had gone down the blow off was closed. The tank was very hot and the roof of the building somewhat scorched. The office was then partially cleaned up but it was decided to leave the tunnel closed until the next day.' 'Aug. 2. The tunnel door was opened in the morning and the compressor run to expel the gasses. About noon it was possible to swing back then honeycomb. It was apparent that the damage was very wide spread. All of the woodwork seemed to be charred and the upper part of the balance ring and the propeller tips and glass windows near the test section were melted. The remainder of the day was spent ventilating the tunnel and taking

  11. Fire in Variable Density Wind Tunnel

    NASA Technical Reports Server (NTRS)

    1927-01-01

    Fire gutted interior of Variable-Density Tunnel (VDT). On August 1, 1927 a major fire broke out inside the VDT. Clean-up, repair, redesign and reinstallation of equipment took about 8 months. From the Variable Density Tunnel Log Book: 'Aug. 1. Computation of the previous tests were in progress in the office and the tank had been pumped up to 20 atmospheres and run to equalize the temperatures about 11:25 a.m. The 20 atmosphere run on the M-6 polished air foil was started and two readings had been taken when sparks were seen to pass in the return passage. Mr. Turner yelled 'Fire!' and shut off the drive motor and opened the blow off valve. Through the peep holes it could be seen that the fire had a good start. It soon fogged up inside so that it could no longer be seen. We then waited for the pressure to go down. However, due to the burning inside, the pressure probably continued to rise. We noticed that the blow off pipe was becoming very hot and that smoke was coming out around the propeller shaft. Suddenly (sic) there was a loud bursting noise and every one left the building. This was probably the blowing of the gasket around the blow off valve. Later the top peep hole blew out and the blow off pipe blew out from the valve. The pressure then began to go down and we returned. The building was full of smoke. When the pressure had gone down the blow off was closed. The tank was very hot and the roof of the building somewhat scorched. The office was then partially cleaned up but it was decided to leave the tunnel closed until the next day.' 'Aug. 2. The tunnel door was opened in the morning and the compressor run to expel the gasses. About noon it was possible to swing back the honeycomb. It was apparent that the damage was very wide spread. All of the woodwork seemed to be charred and the upper part of the balance ring and the propeller tips and glass windows near the test section were melted. The remainder of the day was spent ventilating the tunnel and taking

  12. Soluble platelet-endothelial cell adhesion molecule-1, a biomarker of ventilator-induced lung injury

    PubMed Central

    2014-01-01

    Introduction Endothelial cell injury is an important component of acute lung injury. Platelet-endothelial cell adhesion molecule-1 (PECAM1) is a transmembrane protein that connects endothelial cells to one another and can be detected as a soluble, truncated protein (sPECAM1) in serum. We hypothesized that injurious mechanical ventilation (MV) leads to shedding of PECAM1 from lung endothelial cells resulting in increasing sPECAM1 levels in the systemic circulation. Methods We studied 36 Sprague–Dawley rats in two prospective, randomized, controlled studies (healthy and septic) using established animal models of ventilator-induced lung injury. Animals (n = 6 in each group) were randomized to spontaneous breathing or two MV strategies: low tidal volume (VT) (6 ml/kg) and high-VT (20 ml/kg) on 2 cmH2O of positive end-expiratory pressure (PEEP). In low-VT septic animals, 10 cmH2O of PEEP was applied. We performed pulmonary histological and physiological evaluation and measured lung PECAM1 protein content and serum sPECAM1 levels after four hours ventilation period. Results High-VT MV caused severe lung injury in healthy and septic animals, and decreased lung PECAM1 protein content (P < 0.001). Animals on high-VT had a four- to six-fold increase of mean sPECAM1 serum levels than the unventilated counterpart (35.4 ± 10.4 versus 5.6 ± 1.7 ng/ml in healthy rats; 156.8 ± 47.6 versus 35.6 ± 12.6 ng/ml in septic rats) (P < 0.0001). Low-VT MV prevented these changes. Levels of sPECAM1 in healthy animals on high-VT MV paralleled the sPECAM1 levels of non-ventilated septic animals. Conclusions Our findings suggest that circulating sPECAM1 may represent a promising biomarker for the detection and monitoring of ventilator-induced lung injury. PMID:24588994

  13. Stroke volume changes induced by a recruitment maneuver predict fluid responsiveness in patients with protective ventilation in the operating theater.

    PubMed

    De Broca, Bruno; Garnier, Jeremie; Fischer, Marc-Olivier; Archange, Thomas; Marc, Julien; Abou-Arab, Osama; Dupont, Hervé; Lorne, Emmanuel; Guinot, Pierre-Grégoire

    2016-07-01

    During abdominal surgery, the use of protective ventilation with a low tidal volume, positive expiratory pressure (PEEP) and recruitment maneuvers (RMs) may limit the applicability of dynamic preload indices. The objective of the present study was to establish whether or not the variation in stroke volume (SV) during an RM could predict fluid responsiveness.We prospectively included patients receiving protective ventilation (tidal volume: 6 mL kg, PEEP: 5-7 cmH2O; RMs). Hemodynamic variables, such as heart rate, arterial pressure, SV, cardiac output (CO), respiratory variation in SV (ΔrespSV) and pulse pressure (ΔrespPP), and the variation in SV (ΔrecSV) as well as pulse pressure (ΔrecPP) during an RM were measured at baseline, at the end of the RM, and after fluid expansion. Responders were defined as patients with an SV increase of at least 15% after infusion of 500 mL of crystalloid solution.Thirty-seven (62%) of the 60 included patients were responders. Responders and nonresponders differed significantly in terms of the median ΔrecSV (26% [19-37] vs 10% [4-12], respectively; P < 0.0001). A ΔrecSV value more than 16% predicted fluid responsiveness with an area under the receiver-operating characteristic curve (AU) of 0.95 (95% confidence interval [CI]: 0.91-0.99; P < 0.0001) and a narrow gray zone between 15% and 17%. The area under the curve values for ΔrecPP and ΔrespSV were, respectively, 0.81 (95%CI: 0.7-0.91; P = 0.0001) and 0.80 (95%CI: 0.70-0.94; P < 0.0001). ΔrespPP did not predict fluid responsiveness.During abdominal surgery with protective ventilation, a ΔrecSV value more than 16% accurately predicted fluid responsiveness and had a narrow gray zone (between 15% and 17%). ΔrecPP and ΔrespSV (but not ΔrespPP) were also predictive. PMID:27428237

  14. Effects of Different Tidal Volume Ventilation on Paraquat-Induced Acute Lung Injury in Piglets

    PubMed Central

    Lan, Chao; Wang, Jinzhu; Li, Li; Li, Haina; Li, Lu; Su, Qianqian; Che, Lu; Liu, Lanping; Di, Min

    2015-01-01

    Background The aim of this study was to explore the effects of different tidal volume (VT) ventilation on paraquat-induced acute lung injury or acute respiratory distress syndrome (ALI/ARDS) in piglets. Material/Methods We developed ALI/ARDS models in piglets by intraperitoneal injection of paraquat (PQ). The piglets were randomly divided into three groups: small VT group (VT=6 ml/kg, n=6), middle VT group (VT=10 ml/kg, n=6), and large VT group (VT=15 ml/kg, n=6), with the positive end-expiratory pressure (PEEP) set as 10 cmH2O. The hemodynamics were monitored by pulse-indicated continuous cardiac output (PiCCO) and the airway pressure changes and blood gas analysis indexes were recorded at different time points. The pathological changes were observed by lung puncture. Results The piglets showed ALI/ARDS in 4.5±0.8 hours after PQ intraperitoneal injection. PH, PaO2 and oxygenation indexes in the three groups all decreased after modeling success compared with baseline, and PaCO2 increased significantly. PH in the small VT group decreased most obviously after ventilation for 6 hours. PaO2 and oxygenation indexes in the small VT group showed the most obvious increase after ventilation for 2 hours and were much higher than the other two groups after ventilation for 6 hours. PaCO2 increased gradually after mechanical ventilation and the small VT group showed most obvious increase. The ELWI increased obviously after ventilation for 2 hours and then the small VT group clearly decreased. PIP and plateau pressure (Pplat) in the small VT group decreased gradually and in the middle and large VT group they increased after ventilation. The lung histopathology showed that the large VT group had the most severe damage and the small VT group had only minimal damage. Conclusions Small tidal volume ventilation combined with PEEP could alleviate the acute lung injury induced by paraquat and improve oxygenation. PMID:25671690

  15. Acute chlorine gas exposure produces transient inflammation and a progressive alteration in surfactant composition with accompanying mechanical dysfunction

    SciTech Connect

    Massa, Christopher B.; Scott, Pamela; Abramova, Elena; Gardner, Carol; Laskin, Debra L.; Gow, Andrew J.

    2014-07-01

    Acute Cl{sub 2} exposure following industrial accidents or military/terrorist activity causes pulmonary injury and severe acute respiratory distress. Prior studies suggest that antioxidant depletion is important in producing dysfunction, however a pathophysiologic mechanism has not been elucidated. We propose that acute Cl{sub 2} inhalation leads to oxidative modification of lung lining fluid, producing surfactant inactivation, inflammation and mechanical respiratory dysfunction at the organ level. C57BL/6J mice underwent whole-body exposure to an effective 60 ppm-hour Cl{sub 2} dose, and were euthanized 3, 24 and 48 h later. Whereas pulmonary architecture and endothelial barrier function were preserved, transient neutrophilia, peaking at 24 h, was noted. Increased expression of ARG1, CCL2, RETLNA, IL-1b, and PTGS2 genes was observed in bronchoalveolar lavage (BAL) cells with peak change in all genes at 24 h. Cl{sub 2} exposure had no effect on NOS2 mRNA or iNOS protein expression, nor on BAL NO{sub 3}{sup −} or NO{sub 2}{sup −}. Expression of the alternative macrophage activation markers, Relm-α and mannose receptor was increased in alveolar macrophages and pulmonary epithelium. Capillary surfactometry demonstrated impaired surfactant function, and altered BAL phospholipid and surfactant protein content following exposure. Organ level respiratory function was assessed by forced oscillation technique at 5 end expiratory pressures. Cl{sub 2} exposure had no significant effect on either airway or tissue resistance. Pulmonary elastance was elevated with time following exposure and demonstrated PEEP refractory derecruitment at 48 h, despite waning inflammation. These data support a role for surfactant inactivation as a physiologic mechanism underlying respiratory dysfunction following Cl{sub 2} inhalation. - Highlights: • Effect of 60 ppm*hr Cl{sub 2} gas on lung inflammation and mechanical function examined. • Pulmonary inflammation is transient and minor.

  16. The effects of the semirecumbent position on hemodynamic status in patients on invasive mechanical ventilation: prospective randomized multivariable analysis

    PubMed Central

    2013-01-01

    Introduction Adopting the 45° semirecumbent position in mechanically ventilated critically ill patients is recommended, as it has been shown to reduce the incidence of ventilator-associated pneumonia. Although the benefits to the respiratory system are clear, it is not known whether elevating the head of the bed results in hemodynamic instability. We examined the effect of head of bed elevation (HBE) on hemodynamic status and investigated the factors that influence mean arterial pressure (MAP) and central venous oxygen saturation (ScvO2) when patients were positioned at 0°, 30°, and 45°. Methods Two hundred hemodynamically stable adults on invasive mechanical ventilation admitted to a multidisciplinary surgical intensive care unit were recruited. Patients' characteristics included catecholamine and sedative doses, the original angle of head of bed elevation (HBE), the level of positive end expiratory pressure (PEEP), duration and mode of mechanical ventilation. A sequence of HBE positions (0°, 30°, and 45°) was adopted in random order, and MAP and ScvO2 were measured at each position. Patients acted as their own controls. The influence of degree of HBE and of the covariables on MAP and ScvO2 was analyzed by using liner mixed models. Additionally, uni- and multivariable logistic regression models were used to indentify risk factors for hypotension during HBE, defined as MAP <65 mmHg. Results Changing HBE from supine to 45° caused significant reductions in MAP (from 83.8 mmHg to 71.1 mmHg, P < 0.001) and ScvO2 (76.1% to 74.3%, P < 0.001). Multivariable modeling revealed that mode and duration of mechanical ventilation, the norepinephrine dose, and HBE had statistically significant influences. Pressure-controlled ventilation was the most influential risk factor for hypotension when HBE was 45° (odds ratio (OR) 2.33, 95% confidence interval (CI), 1.23 to 4.76, P = 0.017). Conclusions HBE to the 45° position is associated with significant decreases in MAP and

  17. Evaluation of carbon dioxide rebreathing during pressure support ventilation with airway management system (BiPAP) devices.

    PubMed

    Lofaso, F; Brochard, L; Touchard, D; Hang, T; Harf, A; Isabey, D

    1995-09-01

    The purpose of this study was to evaluate whether carbon dioxide (CO2) rebreathing occurs in acute respiratory failure patients ventilated using the standard airway management system (BiPAP pressure support ventilator; Respironics; Murrysville, Pa) with positive inspiratory airway pressure and a minimal level of positive end-expiratory pressure (PEEP) and whether any CO2 rebreathing may be efficiently prevented by the addition of a nonrebreathing valve to the BiPAP system circuit. In the first part of the study, the standard device was tested on a lung model with a nonrebreathing valve (BiPAP-NRV) and with the usual Whisper Swivel connector (BiPAP-uc). With the BiPAP-uc device, the resident volume of expired air in the inspiratory circuit at the end of expiration (RVEA) was 55% of the tidal volume (VT) when the inspiratory pressure was 10 cm H2O and the frequency was at 15 cycles per minute. The BiPAP-NRV device efficiently prevented CO2 rebreathing but resulted in a slight decrease in VT, which was due to a significant increase in external PEEP (2.4 vs 1.3 cm H2O) caused by the additional expiratory valve resistance. For similar reasons, both the pressure swing necessary to trigger pressure support and the imposed expiratory work were increased in the lung model when the nonrebreathing valve was used. In the second part of the study, seven patients weaned from mechanical ventilation were investigated using a randomized crossover design to compare three situations: pressure support ventilation with a conventional intensive care ventilator (CIPS), BiPAP system use, and BiPAP-NRV. When we compared the BiPAP system use with the other two systems, we observed no significant effect on blood gases but found significant increases in VT, minute ventilation, and work of breathing. These findings are experimental and are clinical evidence that significant CO2 rebreathing occurs with the standard BiPAP system. This drawback can be overcome by using a non-rebreathing valve

  18. Stroke volume changes induced by a recruitment maneuver predict fluid responsiveness in patients with protective ventilation in the operating theater

    PubMed Central

    De Broca, Bruno; Garnier, Jeremie; Fischer, Marc-Olivier; Archange, Thomas; Marc, Julien; Abou-Arab, Osama; Dupont, Hervé; Lorne, Emmanuel; Guinot, Pierre-grégoire

    2016-01-01

    Abstract During abdominal surgery, the use of protective ventilation with a low tidal volume, positive expiratory pressure (PEEP) and recruitment maneuvers (RMs) may limit the applicability of dynamic preload indices. The objective of the present study was to establish whether or not the variation in stroke volume (SV) during an RM could predict fluid responsiveness. We prospectively included patients receiving protective ventilation (tidal volume: 6 mL kg−1, PEEP: 5–7 cmH2O; RMs). Hemodynamic variables, such as heart rate, arterial pressure, SV, cardiac output (CO), respiratory variation in SV (ΔrespSV) and pulse pressure (ΔrespPP), and the variation in SV (ΔrecSV) as well as pulse pressure (ΔrecPP) during an RM were measured at baseline, at the end of the RM, and after fluid expansion. Responders were defined as patients with an SV increase of at least 15% after infusion of 500 mL of crystalloid solution. Thirty-seven (62%) of the 60 included patients were responders. Responders and nonresponders differed significantly in terms of the median ΔrecSV (26% [19–37] vs 10% [4–12], respectively; P < 0.0001). A ΔrecSV value more than 16% predicted fluid responsiveness with an area under the receiver-operating characteristic curve (AU) of 0.95 (95% confidence interval [CI]: 0.91–0.99; P < 0.0001) and a narrow gray zone between 15% and 17%. The area under the curve values for ΔrecPP and ΔrespSV were, respectively, 0.81 (95%CI: 0.7–0.91; P = 0.0001) and 0.80 (95%CI: 0.70–0.94; P < 0.0001). ΔrespPP did not predict fluid responsiveness. During abdominal surgery with protective ventilation, a ΔrecSV value more than 16% accurately predicted fluid responsiveness and had a narrow gray zone (between 15% and 17%). ΔrecPP and ΔrespSV (but not ΔrespPP) were also predictive. PMID:27428237

  19. New method of preoxygenation for orotracheal intubation in patients with hypoxaemic acute respiratory failure in the intensive care unit, non-invasive ventilation combined with apnoeic oxygenation by high flow nasal oxygen: the randomised OPTINIV study protocol

    PubMed Central

    Jaber, Samir; Molinari, Nicolas; De Jong, Audrey

    2016-01-01

    Introduction Tracheal intubation in the intensive care unit (ICU) is associated with severe life-threatening complications including severe hypoxaemia. Preoxygenation before intubation has been recommended in order to decrease such complications. Non-invasive ventilation (NIV)-assisted preoxygenation allows increased oxygen saturation during the intubation procedure, by applying a positive end-expiratory pressure (PEEP) to prevent alveolar derecruitment. However, the NIV mask has to be taken off after preoxygenation to allow the passage of the tube through the mouth. The patient with hypoxaemia does not receive oxygen during this period, at risk of major hypoxaemia. High-flow nasal cannula oxygen therapy (HFNC) has a potential for apnoeic oxygenation during the apnoea period following the preoxygenation with NIV. Whether application of HFNC combined with NIV is more effective at reducing oxygen desaturation during the intubation procedure compared with NIV alone for preoxygenation in patients with hypoxaemia in the ICU with acute respiratory failure remains to be established. Methods and analysis The HFNC combined to NIV for decreasing oxygen desaturation during the intubation procedure in patients with hypoxaemia in the ICU (OPTINIV) trial is an investigator-initiated monocentre randomised controlled two-arm trial with assessor-blinded outcome assessment. The OPTINIV trial randomises 50 patients with hypoxaemia requiring orotracheal intubation for acute respiratory failure to receive NIV (pressure support=10, PEEP=5, fractional inspired oxygen (FiO2)=100%) combined with HFNC (flow=60 L/min, FiO2=100%, interventional group) or NIV alone (reference group) for preoxygenation. The primary outcome is lowest oxygen saturation during the intubation procedure. Secondary outcomes are intubation-related complications, quality of preoxygenation and ICU mortality. Ethics and dissemination The study project has been approved by the appropriate ethics committee (CPP Sud

  20. Early Detection of Ventilation-Induced Brain Injury Using Magnetic Resonance Spectroscopy and Diffusion Tensor Imaging: An In Vivo Study in Preterm Lambs

    PubMed Central

    Skiöld, Béatrice; Wu, Qizhu; Hooper, Stuart B.; Davis, Peter G.; McIntyre, Richard; Tolcos, Mary; Pearson, James; Vreys, Ruth; Egan, Gary F.; Barton, Samantha K.; Cheong, Jeanie L. Y.; Polglase, Graeme R.

    2014-01-01

    Background and Aim High tidal volume (VT) ventilation during resuscitation of preterm lambs results in brain injury evident histologically within hours after birth. We aimed to investigate whether magnetic resonance spectroscopy (MRS) and/or diffusion tensor imaging (DTI) can be used for early in vivo detection of ventilation-induced brain injury in preterm lambs. Methods Newborn lambs (0.85 gestation) were stabilized with a “protective ventilation” strategy (PROT, n = 7: prophylactic Curosurf, sustained inflation, VT 7 mL/kg, positive end expiratory pressure (PEEP) 5 cmH2O) or an initial 15 minutes of “injurious ventilation” (INJ, n = 10: VT 12 mL/kg, no PEEP, late Curosurf) followed by PROT ventilation for the remainder of the experiment. At 1 hour, lambs underwent structural magnetic resonance imaging (Siemens, 3 Tesla). For measures of mean/axial/radial diffusivity (MD, AD, RD) and fractional anisotropy (FA), 30 direction DTI was performed. Regions of interests encompassed the thalamus, internal capsule, periventricular white matter and the cerebellar vermis. MRS was performed using a localized single-voxel (15×15×20 mm3, echo time 270 ms) encompassing suptratentorial deep nuclear grey matter and central white matter. Peak-area ratios for lactate (Lac) relative to N-acetylaspartate (NAA), choline (Cho) and creatine (Cr) were calculated. Groups were compared using 2-way RM-ANOVA, Mann-Whitney U-test and Spearman's correlations. Results No cerebral injury was seen on structural MR images. Lambs in the INJ group had higher mean FA and lower mean RD in the thalamus compared to PROT lambs, but not in the other regions of interest. Peak-area lactate ratios >1.0 was only seen in INJ lambs. A trend of higher mean peak-area ratios for Lac/Cr and Lac/Cho was seen, which correlated with lower pH in both groups. Conclusion Acute changes in brain diffusion measures and metabolite peak-area ratios were observed after injurious ventilation. Early MRS/DTI is

  1. An estimation of mechanical stress on alveolar walls during repetitive alveolar reopening and closure.

    PubMed

    Chen, Zheng-Long; Song, Yuan-Lin; Hu, Zhao-Yan; Zhang, Su; Chen, Ya-Zhu

    2015-08-01

    Alveolar overdistension and mechanical stresses generated by repetitive opening and closing of small airways and alveoli have been widely recognized as two primary mechanistic factors that may contribute to the development of ventilator-induced lung injury. A long-duration exposure of alveolar epithelial cells to even small, shear stresses could lead to the changes in cytoskeleton and the production of inflammatory mediators. In this paper, we have made an attempt to estimate in situ the magnitudes of mechanical stresses exerted on the alveolar walls during repetitive alveolar reopening by using a tape-peeling model of McEwan and Taylor (35). To this end, we first speculate the possible ranges of capillary number (Ca) ≡ μU/γ (a dimensionless combination of surface tension γ, fluid viscosity μ, and alveolar opening velocity U) during in vivo alveolar opening. Subsequent calculations show that increasing respiratory rate or inflation rate serves to increase the values of mechanical stresses. For a normal lung, the predicted maximum shear stresses are <15 dyn/cm(2) at all respiratory rates, whereas for a lung with elevated surface tension or viscosity, the maximum shear stress will notably increase, even at a slow respiratory rate. Similarly, the increased pressure gradients in the case of elevated surface or viscosity may lead to a pressure drop >300 dyn/cm(2) across a cell, possibly inducing epithelial hydraulic cracks. In addition, we have conceived of a geometrical model of alveolar opening to make a prediction of the positive end-expiratory pressure (PEEP) required to splint open a collapsed alveolus, which as shown by our results, covers a wide range of pressures, from several centimeters to dozens of centimeters of water, strongly depending on the underlying pulmonary conditions. The establishment of adequate regional ventilation-to-perfusion ratios may prevent recruited alveoli from reabsorption atelectasis and accordingly, reduce the required levels of

  2. Lung-protective Ventilation in Patients with Brain Injury: A Multicenter Cross-sectional Study and Questionnaire Survey in China

    PubMed Central

    Luo, Xu-Ying; Hu, Ying-Hong; Cao, Xiang-Yuan; Kang, Yan; Liu, Li-Ping; Wang, Shou-Hong; Yu, Rong-Guo; Yu, Xiang-You; Zhang, Xia; Li, Bao-Shan; Ma, Zeng-Xiang; Weng, Yi-Bing; Zhang, Heng; Chen, De-Chang; Chen, Wei; Chen, Wen-Jin; Chen, Xiu-Mei; Du, Bin; Duan, Mei-Li; Hu, Jin; Huang, Yun-Feng; Jia, Gui-Jun; Li, Li-Hong; Liang, Yu-Min; Qin, Bing-Yu; Wang, Xian-Dong; Xiong, Jian; Yan, Li-Mei; Yang, Zheng-Ping; Dong, Chen-Ming; Wang, Dong-Xin; Zhan, Qing-Yuan; Fu, Shuang-Lin; Zhao, Lin; Huang, Qi-Bing; Xie, Ying-Guang; Huang, Xiao-Bo; Zhang, Guo-Bin; Xu, Wang-Bin; Xu, Yuan; Liu, Ya-Ling; Zhao, He-Ling; Sun, Rong-Qing; Sun, Ming; Cheng, Qing-Hong; Qu, Xin; Yang, Xiao-Feng; Xu, Ming; Shi, Zhong-Hua; Chen, Han; He, Xuan; Yang, Yan-Lin; Chen, Guang-Qiang; Sun, Xiu-Mei; Zhou, Jian-Xin

    2016-01-01

    Background: Over the years, the mechanical ventilation (MV) strategy has changed worldwide. The aim of the present study was to describe the ventilation practices, particularly lung-protective ventilation (LPV), among brain-injured patients in China. Methods: This study was a multicenter, 1-day, cross-sectional study in 47 Intensive Care Units (ICUs) across China. Mechanically ventilated patients (18 years and older) with brain injury in a participating ICU during the time of the study, including traumatic brain injury, stroke, postoperation with intracranial tumor, hypoxic-ischemic encephalopathy, intracranial infection, and idiopathic epilepsy, were enrolled. Demographic data, primary diagnoses, indications for MV, MV modes and settings, and prognoses on the 60th day were collected. Multivariable logistic analysis was used to assess factors that might affect the use of LPV. Results: A total of 104 patients were enrolled in the present study, 87 (83.7%) of whom were identified with severe brain injury based on a Glasgow Coma Scale ≤8 points. Synchronized intermittent mandatory ventilation (SIMV) was the most frequent ventilator mode, accounting for 46.2% of the entire cohort. The median tidal volume was set to 8.0 ml/kg (interquartile range [IQR], 7.0–8.9 ml/kg) of the predicted body weight; 50 (48.1%) patients received LPV. The median positive end-expiratory pressure (PEEP) was set to 5 cmH2O (IQR, 5–6 cmH2O). No PEEP values were higher than 10 cmH2O. Compared with partially mandatory ventilation, supportive and spontaneous ventilation practices were associated with LPV. There were no significant differences in mortality and MV duration between patients subjected to LPV and those were not. Conclusions: Among brain-injured patients in China, SIMV was the most frequent ventilation mode. Nearly one-half of the brain-injured patients received LPV. Patients under supportive and spontaneous ventilation were more likely to receive LPV. Trial Registration: Clinical

  3. Initial synchronized intermittent mandatory ventilation versus assist/control ventilation in treatment of moderate acute respiratory distress syndrome: a prospective randomized controlled trial

    PubMed Central

    Luo, Jian; Wang, Mao-Yun; Liang, Bin-Miao; Yu, He; Jiang, Fa-Ming; Wang, Ting; Shi, Chao-Li; Li, Pei-Jun; Liu, Dan; Wu, Xiao-Ling

    2015-01-01

    Background Assist/control (A/C) ventilation may induce delirium in patients with acute respiratory distress syndrome (ARDS). We conducted a trial to determine whether initial synchronized intermittent mandatory ventilation with pressure support (SIMV + PS) could improve clinical outcomes in these patients. Methods Intubated patients with moderate ARDS were enrolled and we compared SIMV + PS with A/C. Identical sedation, analgesia and ventilation strategies were performed. The co-primary outcomes were early (≤72 h) partial pressure of arterial oxygen to fraction of inspired oxygen (PaO2/FiO2) and incidence of delirium. The secondary outcomes were all-cause in-hospital mortality, dosages of analgesics and sedatives, incidence of patient-ventilator asynchrony, and duration of mechanical ventilation and hospital stay. Results We screened 2,684 patients and 40 patients were enrolled in our study. In SIMV + PS, early (≤72 h) PaO2/FiO2 was greater improved than that at baseline and that in A/C (P<0.05) with lower positive end-expiratory pressure (PEEP) (8.7±3.0 vs. 10.3±3.2, P<0.001) and FiO2 (58%±18% vs. 67%±19%, P<0.001). We found more SIMV + PS success (defined as SIMV + PS successfully applied without switching to A/C) (100.0% vs. 16.7%, P<0.001), less male (46.3% vs. 85.7%, P=0.015) and pulmonary etiology of ARDS (53.8% vs. 92.9%, P=0.015), and lower PEEP (9.1±3.1 vs. 10.3±3.3, P=0.004) and FiO2 (58%±19% vs. 71%±19%, P<0.001) in survival patients. However, there were no significant differences in incidence of delirium and mortality, dosages of analgesics and sedatives, incidence of patient-ventilator asynchrony, duration of mechanical ventilation and hospital stay (P>0.05). Conclusions In patients with moderate ARDS, SIMV + PS can safely and effectively improve oxygenation, but does not decrease mortality, incidence of delirium and patient-ventilator asynchrony, dosages of analgesics and sedatives, and duration of mechanical ventilation and hospital stay

  4. [The protocol for multi organ donor management].

    PubMed

    Kucewicz, Ewa; Wojarski, Jacek; Zegleń, Sławomir; Saucha, Wojciech; Maciejewski, Tomasz; Pacholewicz, Jerzy; Przybylski, Roman; Knapik, Piotr; Zembala, Marian

    2009-01-01

    Identification and preparation of a potential organ donor requires careful and meticulous intensive care, so that the organs may be harvested in the best possible condition for transplantation. The protocol consists of three key elements: (1) monitoring and haemodynamicstabilisation, (2) hormonal therapy, and (3) adequate mechanical ventilation and nosocomial pneumonia prophylaxis. Standard haemodynamic monitoring should consist of a 12 lead EGG, and direct monitoring of arterial and central venous pressures. Pulmonary artery catheterisation is indicated in donors with a left ventricular ejection fraction (LVEF) below 45%. PCWP should be kept at around 12 mm Hg, Cl at greater than 2.4 L m(-2), and SVR between 800 and 1200 dyn s(-1) cm(-5). When a vasopressor is necessary, vasopressin should be used as the drug of choice. If vasopressin is not available, noradrenaline or adrenaline may be used. Haemoglobin concentration should be maintained between 5.5-6.2 mmol L(-1). In a potential heart donor, troponin concentration should be checked daily. Neutral thermal conditions should be maintained using a warm air blower. A brain dead patient cannot maintain adequate pituitary function, therefore hormone replacement therapy with methylprednisolone, thyroxin and desmopressin is indicated. Glucose concentrations should be kept within the normal range, using insulin if necessary. The lung harvesting protocol should be similarto ARDS treatment guidelines (optimal PEEP, low tidal volumes). Lung recruitment manoeuvres, and aggressive prevention and treatment of nosocomial infection are essential. PMID:20201348

  5. Ventilation and gas exchange management after cardiac arrest.

    PubMed

    Sutherasan, Yuda; Raimondo, Pasquale; Pelosi, Paolo

    2015-12-01

    For several decades, physicians had integrated several interventions aiming to improve the outcomes in post-cardiac arrest patients. However, the mortality rate after cardiac arrest is still as high as 50%. Post-cardiac arrest syndrome is associated with high morbidity and mortality due to not only poor neurological outcome and cardiovascular failure but also respiratory dysfunction. To minimize ventilator-associated lung injury, protective mechanical ventilation by using low tidal volume ventilation and driving pressure may decrease pulmonary complications and improve survival. Low level of positive end-expiratory pressure (PEEP) can be initiated and titrated with careful cardiac output and respiratory mechanics monitoring. Furthermore, optimizing gas exchange by avoiding hypoxia and hyperoxia as well as maintaining normocarbia may improve neurological and survival outcome. Early multidisciplinary cardiac rehabilitation intervention is recommended. Minimally invasive monitoring techniques, that is, echocardiography, transpulmonary thermodilution method measuring extravascular lung water, as well as transcranial Doppler ultrasound, might be useful to improve appropriate management of post-cardiac arrest patients. PMID:26670813

  6. 16S rRNA gene high-throughput sequencing data mining of microbial diversity and interactions.

    PubMed

    Ju, Feng; Zhang, Tong

    2015-05-01

    The ubiquitous occurrence of microorganisms gives rise to continuous public concerns regarding their pathogenicity and threats to human environment, as well as potential engineering benefits in biotechnology. The development and wide application of environmental biotechnology, for example in bioenergy production, wastewater treatment, bioremediation, and drinking water disinfection, have been bringing us with both environmental and economic benefits. Strikingly, extensive applications of microscopic and molecular techniques since 1990s have allowed engineers to peep into the microbiology in "black box" of engineered microbial communities in biotechnological processes, providing guidelines for process design and optimization. Recently, revolutionary advances in DNA sequencing technologies and rapidly decreasing costs are altering conventional ways of microbiology and ecology research, as it launches an era of next-generation sequencing (NGS). The principal research burdens are now transforming from traditional labor-intensive wet-lab experiments to dealing with analysis of huge and informative NGS data, which is computationally expensive and bioinformatically challenging. This study discusses state-of-the-art bioinformatics and statistical analyses of 16S ribosomal RNA (rRNA) gene high-throughput sequencing (HTS) data from prevalent NGS platforms to promote its applications in exploring microbial diversity of functional and pathogenic microorganisms, as well as their interactions in biotechnological processes. PMID:25808518

  7. [Legionella pneumonia which occurred in a private whirlpool bath user].

    PubMed

    Ishikawa, Akira; Okada, Jun; Kondo, Hirobumi; Takayama, Youko; Sunagawa, Keisuke; Enari, Tadako; Ishii, Yoshikazu

    2004-10-01

    A 88 year old female with active rheumatoid arthritis treated by low dose of prednisolone and methotrexate was admitted to our hospital because of severe bilateral pulmonary infiltration and acute respiratory distress syndrome. On admission, she had consciousness disturbance and was intubated because of severe respiratory failure. We heard from her family of her habit she had taking a private whirlpool bath 2 or 3 times everyday. So, we suspected a Legionella pneumophila infection. We started intravenous erythromycin (EM) (1,500mg/day) and methylprednisolone pulse therapy (1,000mg x 3days) and full controlled mechanical ventilation supported with PEEP. Her respiratory failure was gradually improved and she was discharged on the 44 the hospital day. Legionella pneumophila (serogroup 6) was isolated in her sputum by B-CYE alpha culture. Legionella pneumophila (serogroup 6) was isolated in her private whirlpool bath too. Both samples revealed the same by genetic analysis with pulse field gel electrophoresis (PFGE). This is the first adult case of Legionella pneumophila pneumonia infected from a private whirlpool bath confirmed by genetic analysis. We should always suspect Legionella pneumonia as one of the severe community-acquired pneumonia, because Legionella pneumophila were frequently detected among various water sources including the private whirlpool bath. PMID:15560380

  8. Reclutamento alveolare in sala parto: la sustained lung inflation. (Alveolar recruitment in the delivery room: sustained lung inflation).

    PubMed

    Lista, G; Castoldi, F

    2010-06-01

    At birth the transition by the fetal situation to neonatal life occurs. The real mechanism of lung liquid reabsorption and lung aereation at birth, in the past attributed only to the epithelial sodium channel function, has recently been linked to the first important breaths too and to the following changes in transpulmonary pressure. If this quite easily happens in the term baby, the preterm infants and all the babies with poor respiratory effort may have a delayed achievement of an adequate functional residual capacity (FRC). Premature delivery is always associated to the failure of respiratory transition and preterm babies frequently need a respiratory support (e.g., N-CPAP). Actual recommendations do not consider to mimic the physiologic changes that usually happen to the term neonate at birth. The application at birth of the sustained lung inflation (SLI) (a peak pressure of 25-30 cm H2O for 10-20 seconds), with nasopharyngeal tube or an adequately sized mask and a Neo-puff device, followed by the application of a continuous adequate PEEP (e.g., 5 cmH2O) is effective in the achievement of the FRC in animal studies and in the reduction of the need of mechanical ventilation (MV) in preterm infants at risk for RDS. Large RCTs are needed to verify the real efficacy of SLI in the delivery room to prevent the need of mechanical ventilation and to improve respiratory outcomes of preterm infants at risk for RDS. PMID:21089711

  9. [Intraoperative risk management during thoracic procedures].

    PubMed

    Tsuzaki, Koichi

    2009-05-01

    Risk management in clinical practice is an impor part of medical audit. Although, medical audit consists of monitoring, data collection, peer review and establishing standards, these four steps should be regarded as a series of cyclical process. As a general rule, this concept should be applied to any field of clinical medicine and will contribute to the development of sound quality control scheme. Several complications are known to occur in thoracic anesthesia, especially in one-lung ventilation. For example, malposition of double-lumen endotracheal tube, severe hypoxia and higher airway pressure are relatively common problems, and it would be better for us to prepare for these adverse events beforehand. Auscultation, fiber-optic visualization and proper ventilatory management (eg. lower tidal volume with dependent lung PEEP, alveolar recruitment maneuver, application of CPAP to non-dependent lung) are the recommended technique required to correct these abnormalities. When life-threatening hypoxia is imminent, we should convert to two-lung ventilation without any delay. In this regard, verbal communication between surgical teams should be kept on even ground, each playing key roles in the management of such a critical situation. PMID:19462793

  10. The Vocal Repertoire of the African Penguin (Spheniscus demersus): Structure and Function of Calls

    PubMed Central

    Favaro, Livio; Ozella, Laura; Pessani, Daniela

    2014-01-01

    The African Penguin (Spheniscus demersus) is a highly social and vocal seabird. However, currently available descriptions of the vocal repertoire of African Penguin are mostly limited to basic descriptions of calls. Here we provide, for the first time, a detailed description of the vocal behaviour of this species by collecting audio and video recordings from a large captive colony. We combine visual examinations of spectrograms with spectral and temporal acoustic analyses to determine vocal categories. Moreover, we used a principal component analysis, followed by signal classification with a discriminant function analysis, for statistical validation of the vocalisation types. In addition, we identified the behavioural contexts in which calls were uttered. The results show that four basic vocalisations can be found in the vocal repertoire of adult African Penguin, namely a contact call emitted by isolated birds, an agonistic call used in aggressive interactions, an ecstatic display song uttered by single birds, and a mutual display song vocalised by pairs, at their nests. Moreover, we identified two distinct vocalisations interpreted as begging calls by nesting chicks (begging peep) and unweaned juveniles (begging moan). Finally, we discussed the importance of specific acoustic parameters in classifying calls and the possible use of the source-filter theory of vocal production to study penguin vocalisations. PMID:25076136

  11. "Intrinsic" positive end-expiratory pressure in stable patients with chronic obstructive pulmonary disease.

    PubMed

    Dal Vecchio, L; Polese, G; Poggi, R; Rossi, A

    1990-01-01

    We have assessed "intrinsic" positive end-expiratory pressure (PEEPi), during quiet breathing in 18 patients with chronic obstructive pulmonary disease (COPD) in stable condition. Ventilatory flow, lung volume, oesophageal (Poes), gastric (Pga), and transdiaphragmatic pressure (Pdi) were measured. PEEPi was measured as the pressure difference (delta Poes) between the onset of the inspiratory effort, indicated by the start of the Pdi swing, and the point corresponding to zero flow. PEEPi was present in all of the 18 COPD patients, and averaged 2.4 +/- 1.6 cmH2O. The maximum transdiaphragmatic pressure (Pdi,max) was also measured and averaged 81.5 +/- 17.4 cmH2O. Following a randomized sequence, ten patients then inhaled an adrenergic agonist (fenoterol 1.6 mg), and eight patients the corresponding placebo. Fenoterol, but not placebo, caused a significant increase in forced expiratory volume in one second (FEV1) (+34%, on average), associated with a significant decrease in PEEPi (-63%, on average) and a significant improvement in Pdi,max (+19%, on average). We conclude that: 1) intrinsic PEEP can be present in stable COPD patients due to increased airflow resistance; 2) fenoterol improved diaphragmatic strength (Pdi,max) in our COPD patients, possibly due to a decrease in lung volume. PMID:2178961

  12. High-flow nasal cannula oxygen therapy in adults.

    PubMed

    Nishimura, Masaji

    2015-01-01

    High-flow nasal cannula (HFNC) oxygen therapy comprises an air/oxygen blender, an active humidifier, a single heated circuit, and a nasal cannula. It delivers adequately heated and humidified medical gas at up to 60 L/min of flow and is considered to have a number of physiological effects: reduction of anatomical dead space, PEEP effect, constant fraction of inspired oxygen, and good humidification. While there have been no big randomized clinical trials, it has been gaining attention as an innovative respiratory support for critically ill patients. Most of the available data has been published in the neonatal field. Evidence with critically ill adults are poor; however, physicians apply it to a variety of patients with diverse underlying diseases: hypoxemic respiratory failure, acute exacerbation of chronic obstructive pulmonary disease, post-extubation, pre-intubation oxygenation, sleep apnea, acute heart failure, patients with do-not-intubate order, and so on. Many published reports suggest that HFNC decreases breathing frequency and work of breathing and reduces needs of escalation of respiratory support in patients with diverse underlying diseases. Some important issues remain to be resolved, such as its indication, timing of starting and stopping HFNC, and escalating treatment. Despite these issues, HFNC oxygen therapy is an innovative and effective modality for the early treatment of adults with respiratory failure with diverse underlying diseases. PMID:25866645

  13. Physisporinus vitreus: a versatile white rot fungus for engineering value-added wood products.

    PubMed

    Schwarze, Francis W M R; Schubert, Mark

    2011-11-01

    The credo of every scientist working in the field of applied science is to transfer knowledge "from science to market," a process that combines (1) science (fundamental discoveries and basic research) with (2) technology development (performance assessment and optimization) and (3) technology transfer (industrial application). Over the past 7 years, we have intensively investigated the potential of the white rot fungus, Physisporinus vitreus, for engineering value-added wood products. Because of its exceptional wood degradation pattern, i.e., selective lignification without significant wood strength losses and a preferential degradation of bordered pit membranes, it is possible to use this fungus under controlled conditions to improve the acoustic properties of tonewood (i.e., "mycowood") as well as to enhance the uptake of preservatives and wood modification substances in refractory wood species (e.g., Norway spruce), a process known as "bioincising." This minireview summarizes the research that we have performed with P. vitreus and critically discusses the challenges encountered during the development of two distinct processes for engineering value-added wood products. Finally, we peep into the future potential of the bioincising and mycowood processes for additional applications in the forest and wood industry. PMID:21901405

  14. Real-time respiratory monitoring workstation--software and hardware engineering aspects.

    PubMed

    Govindarajan, N; Meiyappan, S; Prakash, O

    1992-10-01

    We have applied advanced real-time techniques in software, that are intensively used in critical areas like space research and defence applications, to realise an Integrated Real-Time Respiratory Monitoring System at the Thorax Anesthesiology, Academic Hospital Rotterdam. The system is called the 'SERVO WINDOW'--a window to the servo ventilator. The heart of the system is a real-time kernel that uses preemptive scheduling to achieve multitasking on a IBM PC compatible hardware platform. To the clinician this means that he gets all relevant information from one source i.e. the Respiratory Workstation. The waveforms of the airway pressure, airway flow and the expired CO2 curve are displayed continuously on the screen. The Vector Loops like Pressure Volume, Flow Pressure and Flow Volume loops are also available in addition to the lung mechanics parameters like Expiratory and Inspiratory Resistances, Compliances, Peak Pressure, PEEP, etc. The Single Breath Diagram i.e. expired CO2 concentration versus volume and dead space ventilation is also calculated. The blood gas analysis data is plotted in convenient diagrams like the O2-CO2 diagram, Oxygen Chart, etc. The trend of all these parameters are available with a granularity of one minute. An industry standard laser printer is used for report generation to produce reports of the real-time waveforms, parameter values and the trends. User interface is through easy menus with the traditional keyboard, touchscreen including keyboard on screen for data entry and the mouse. PMID:1447536

  15. Monitoring oxygenation.

    PubMed

    Severinghaus, John W

    2011-06-01

    Cyanosis was used for a century after dentists began pulling teeth under 100% N(2)O in 1844 because brief (2 min) severe hypoxia is harmless. Deaths came with curare and potent anesthetic respiratory arrest. Leland Clark's invention of a polarographic blood oxygen tension electrode (1954) was introduced for transcutaneous PO2 monitoring to adjust PEEP and CPAP PO2 to prevent premature infant blindness from excess O2 (1972). Oximetry for warning military aviators was tried after WW II but not used for routine monitoring until Takuo Aoyagi (1973) discovered an equation to measure SaO2 by the ratio of ratios of red and IR light transmitted through tissue as it changed with arterial pulses. Pulse oximetry (1982) depended on simultaneous technology improvements of light emitting red and IR diodes, tiny cheap solid state sensors and micro-chip computers. Continuous monitoring of airway anesthetic concentration and oxygen also became very common after 1980. Death from anesthesia fell 10 fold between 1985 and 2000 as pulse oximetry became universally used, but no proof of a causative relationship to pulse oximetry exists. It is now assumed that all anesthesiologist became much more aware of the dangers of prolonged hypoxia, perhaps by using the pulse oximeters. PMID:21717228

  16. Use of helium-oxygen mixture in adult patients presenting with exacerbations of asthma and chronic obstructive pulmonary disease: a systematic review.

    PubMed

    Colebourn, C L; Barber, V; Young, J D

    2007-01-01

    We examined systematically all controlled and cross-over randomised trials in patients with acute exacerbations of asthma and chronic obstructive pulmonary disease comparing Heliox against air-oxygen mixtures. Fourteen studies were identified. In asthma studies, peak expiratory flow rate (PEFR) was increased by an average of 29.6% (95% CI 16.6-42.6) by Heliox-driven nebulisers, or by 13.3 l.min(-1) (95% CI 3.71-22.81) absolute. In studies of patients with chronic obstructive pulmonary disease receiving non-invasive ventilation the arterial carbon dioxide tension (P(a)co(2)) and respiratory rate were unchanged: weighted mean difference for P(a)co(2)-0.29kPa (95% CI - 0.64-0.07) favoured Heliox, and for respiratory rate 1.6 breaths.min(-1) (95% CI - 0.93, 4.14) favoured control. Heliox minimally reduced the work of breathing in intubated patients, and reduced intrinsic positive end expiratory pressure (iPEEP). The use of Heliox to drive nebulisers in patients with acute asthma slightly improves airflow measures. We were unable to determine whether this improved recovery. PMID:17156225

  17. [Current approaches to the treatment of severe hypoxic respiratory insufficiency (acute lung injury; acute respiratory distress syndrome)].

    PubMed

    Kluge, S; Müller, T; Pfeifer, M

    2011-02-01

    Lung-protective ventilation with a low tidal volume, plateau pressure < 30 cm H(2)O. oxygen saturation > 90% and permissive hypercapnia results in reduction of the mortality rate in patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). The level of the positive end-expiratory pressure (PEEP) must be chosen in relation to oxygen requirement. High frequency oscillatory ventilation and neurally adjusted ventilatory assist are promising methods. However, further studies with firm end-points have to be awaited before a final judgment is possible. Veno-venous extracorporeal membrane oxygenation (ECMO) can ensure life-sustaining gas exchange in patients with severe vitally compromised pulmonary failure, to provide time for lung tissue to heal and reduce ventilatory stress. The latest guidelines for analgesia and sedation in intensive care medicine demand consistent monitoring of the level of sedation and the intensity of pain. The sedation should be interrupted daily, with phases of awakenings and, if possible, spontaneous breathing. Methods of supportive treatment: Positional treatment (prone position) and inhalation of vasodilators can improve ventilation/perfusion mismatch and thus oxygenation. However, administration of surfactant is currently not advised in adult respiratory failure. PMID:21271478

  18. Pulmonary perfusion during anesthesia and mechanical ventilation.

    PubMed

    Hedenstierna, G

    2005-06-01

    Cardiac output and the pulmonary perfusion can be affected by anesthesia and by mechanical ventilation. The changes contribute to impeded oxygenation of the blood. The major determinant of perfusion distribution in the lung is the relation between alveolar and pulmonary capillary pressures. Perfusion increases down the lung, due to hydrostatic forces. Since atelectasis is located in dependent lung regions, perfusion of non-ventilated lung parenchyma is common, producing shunt of around 8-10% of cardiac output. In addition, non-gravitational inhomogeneity of perfusion, that can be greater than the gravitational inhomogeneity, adds to impeded oxygenation of blood. Essentially all anaesthetics exert some, although mild, cardiodepressant action with one exception, ketamine. Ketamine may also increase pulmonary artery pressure, whereas other agents have little effect on pulmonary vascular tone. Mechanical ventilation impedes venous return and pushes blood flow downwards to dependent lung regions, and the effect may be striking with higher levels of PEEP. During one-lung anesthesia, there is shunt blood flow both in the non-ventilated and the ventilated lung, and shunt can be much larger in the ventilated lung than thought of. Recruitment manoeuvres shall be directed to the ventilated lung and other physical and pharmacological measures can be taken to manipulate blood flow in one lung anesthesia. PMID:15886595

  19. Impact of mechanical ventilation on the pathophysiology of progressive acute lung injury.

    PubMed

    Nieman, Gary F; Gatto, Louis A; Habashi, Nader M

    2015-12-01

    The earliest description of what is now known as the acute respiratory distress syndrome (ARDS) was a highly lethal double pneumonia. Ashbaugh and colleagues (Ashbaugh DG, Bigelow DB, Petty TL, Levine BE Lancet 2: 319-323, 1967) correctly identified the disease as ARDS in 1967. Their initial study showing the positive effect of mechanical ventilation with positive end-expiratory pressure (PEEP) on ARDS mortality was dampened when it was discovered that improperly used mechanical ventilation can cause a secondary ventilator-induced lung injury (VILI), thereby greatly exacerbating ARDS mortality. This Synthesis Report will review the pathophysiology of ARDS and VILI from a mechanical stress-strain perspective. Although inflammation is also an important component of VILI pathology, it is secondary to the mechanical damage caused by excessive strain. The mechanical breath will be deconstructed to show that multiple parameters that comprise the breath-airway pressure, flows, volumes, and the duration during which they are applied to each breath-are critical to lung injury and protection. Specifically, the mechanisms by which a properly set mechanical breath can reduce the development of excessive fluid flux and pulmonary edema, which are a hallmark of ARDS pathology, are reviewed. Using our knowledge of how multiple parameters in the mechanical breath affect lung physiology, the optimal combination of pressures, volumes, flows, and durations that should offer maximum lung protection are postulated. PMID:26472873

  20. The effect of famotidine on gastroesophageal and duodeno-gastro-esophageal refluxes in critically ill patients

    PubMed Central

    Xin, Ying; Dai, Ning; Zhao, Lan; Wang, Jian-Guo; Si, Jian-Ming

    2003-01-01

    AIM: To investigate the effect of famotidine on gastroesophageal reflux (GER) and duodeno-gastro-esophageal reflux (DGER) and to explore it's possible mechanisms. To identify the relevant factors of the reflux. METHODS: Ninteen critically ill patients were consecutively enrolled in the study. Dynamic 24 h monitoring of GER and DGER before and after administration of famotidine was performed. The parameters of gastric residual volume,multiple organ disorder syndrome (MODS) score, acute physiology and chronic health evaluation II (APACHE II) score and PEEP were recorded. Paired t test; Wilcoxon signed ranks test and Univariate analysis with Spearman's rank correlation were applied to analyse the data. RESULTS: Statistical significance of longest acid reflux, reflux time of pH < 4 and fraction time of acid reflux was observed in ten critically ill patients before and after administration. P value is 0.037, 0.005, 0.005 respectively. Significance change of all bile reflux parameters was observed before and after administration. P value is 0.007, 0.024, 0.005, 0.007, 0.005. GER has positive correlation with APACHE II score and gastric residual volume with correlation coefficient of 0.720, 0.932 respectively. CONCLUSION: GER and DGER are much improved after the administration of famotidine. GER is correlated with APACHE II score and gastric residual volume. PMID:12532466

  1. The vocal repertoire of the African Penguin (Spheniscus demersus): structure and function of calls.

    PubMed

    Favaro, Livio; Ozella, Laura; Pessani, Daniela

    2014-01-01

    The African Penguin (Spheniscus demersus) is a highly social and vocal seabird. However, currently available descriptions of the vocal repertoire of African Penguin are mostly limited to basic descriptions of calls. Here we provide, for the first time, a detailed description of the vocal behaviour of this species by collecting audio and video recordings from a large captive colony. We combine visual examinations of spectrograms with spectral and temporal acoustic analyses to determine vocal categories. Moreover, we used a principal component analysis, followed by signal classification with a discriminant function analysis, for statistical validation of the vocalisation types. In addition, we identified the behavioural contexts in which calls were uttered. The results show that four basic vocalisations can be found in the vocal repertoire of adult African Penguin, namely a contact call emitted by isolated birds, an agonistic call used in aggressive interactions, an ecstatic display song uttered by single birds, and a mutual display song vocalised by pairs, at their nests. Moreover, we identified two distinct vocalisations interpreted as begging calls by nesting chicks (begging peep) and unweaned juveniles (begging moan). Finally, we discussed the importance of specific acoustic parameters in classifying calls and the possible use of the source-filter theory of vocal production to study penguin vocalisations. PMID:25076136

  2. High-Flow Nasal Cannula Oxygen Therapy in Adults: Physiological Benefits, Indication, Clinical Benefits, and Adverse Effects.

    PubMed

    Nishimura, Masaji

    2016-04-01

    High-flow nasal cannula (HFNC) oxygen therapy is carried out using an air/oxygen blender, active humidifier, single heated tube, and nasal cannula. Able to deliver adequately heated and humidified medical gas at flows up to 60 L/min, it is considered to have a number of physiological advantages compared with other standard oxygen therapies, including reduced anatomical dead space, PEEP, constant FIO2 , and good humidification. Although few large randomized clinical trials have been performed, HFNC has been gaining attention as an alternative respiratory support for critically ill patients. Published data are mostly available for neonates. For critically ill adults, however, evidence is uneven because the reports cover various subjects with diverse underlying conditions, such as hypoxemic respiratory failure, exacerbation of COPD, postextubation, preintubation oxygenation, sleep apnea, acute heart failure, and conditions entailing do-not-intubate orders. Even so, across the diversity, many published reports suggest that HFNC decreases breathing frequency and work of breathing and reduces the need for respiratory support escalation. Some important issues remain to be resolved, such as definitive indications for HFNC and criteria for timing the starting and stopping of HFNC and for escalating treatment. Despite these issues, HFNC has emerged as an innovative and effective modality for early treatment of adults with respiratory failure with diverse underlying diseases. PMID:27016353

  3. Monitoring Fluvial Erosion of Cohesive Materials Using the Photo-Electronic Erosion Pin Sensor in Clear Creek, IA

    NASA Astrophysics Data System (ADS)

    Bertrand, F.; Papanicolaou, T.

    2009-12-01

    Fluvial erosion incites significant bridge scour and large-scale bank erosion causing estimated $1.1 billion damage in the Midwest. Conventional, manual, field monitoring methods, typically erosion pins, cross-section resurveys or terrestrial photogrammetry, used to monitor fluvial erosion rates merely provide a net change in bank surface retreat since the previous measurement. If mass wasting has occurred, the ongoing fluvial erosion would be masked. Erosion event timing, and the precise bank response to individual flow or flow hydrograph changes, is generally uncertain. Thus, a technique that automatically quantifies bank erosion on a continuous basis is needed. This study will monitor the bank response to individual flow (i.e., fluvial erosion) using the Photo-Electronic Erosion Pin (PEEP) sensors in Clear Creek Iowa. It attends to monitor a full episode of bank change, including event timings and magnitude information for specific erosion and deposition events, which can be compared to flow discharges and hydrographs. If exploited, this method can lead to more detailed analysis of bank erosion related to temporal fluctuations in the suspected hydraulic forces.

  4. Probing Pb + Pb collisions at √{SNN} = 2760 GeV with spectators

    NASA Astrophysics Data System (ADS)

    Bairathi, Vipul; Chatterjee, Sandeep; Rihan Haque, Md.; Mohanty, Bedangadas

    2016-03-01

    There is event by event geometric as well as quantum fluctuations in the initial condition of heavy-ion collisions. The standard technique of analysing heavy-ion collisions in bins of centrality obtained from final state multiplicity averages out the various initial configurations and thus restricts the study to only a limited range of initial conditions. In this paper, we propose an additional binning in terms of total spectator neutrons in an event. This offers us a key control parameter to probe events with broader range of initial conditions providing us an opportunity to peep into events with rarer initial conditions which otherwise get masked when analysed by centrality binning alone. We find that the inclusion of spectator binning allows one to vary ε2 and ε3 independently. We observe that the standard scaling relation between v2 /ε2 and 1/SdNch/dη exhibited by centrality bins is strongly broken by the spectator neutron bins. Further, the acoustic scaling relation between ln ⁡ (vn /εn) and transverse system size is also broken- the strength of the breaking being sensitive to the binning procedure. The introduction of the spectator binning allows us to tune over a wide range viscosity driven effects for events with varying initial states but similar final state multiplicity.

  5. Acute respiratory distress induced by repeated saline lavage provides stable experimental conditions for 24 hours in pigs.

    PubMed

    Muellenbach, Ralf M; Kredel, Markus; Zollhoefer, Bernd; Bernd, Zollhoefer; Johannes, Amelie; Kuestermann, Julian; Schuster, Frank; Schwemmer, Ulrich; Wurmb, Thomas; Wunder, Christian; Roewer, Norbert; Brederlau, Jörg

    2009-04-01

    Surfactant depletion is most often used to study acute respiratory failure in animal models. Because model stability is often criticized, the authors tested the following hypotheses: Repeated pulmonary lavage with normal saline provides stable experimental conditions for 24 hours with a PaO2/FiO2 ratio < 300 mm Hg. Lung injury was induced by bilateral pulmonary lavages in 8 female pigs (51.5 +/- 4.8 kg). The animals were ventilated for 24 hours (PEEP: 5 cm H2O; tidal volume: 6 mL/kg; respiratory rate: 30/min). After 24 hours the animals were euthanized. For histopathology slides from all pulmonary lobes were obtained. Supernatant of the bronchoalveolar fluid collected before induction of acute respiratory distress syndrome (ARDS) and after 24 hours was analyzed. A total of 19 +/- 6 lavages were needed to induce ARDS. PaO2/FiO2 ratio and pulmonary shunt fraction remained significantly deteriorated compared to baseline values after 24 hours (P < .01). Slight to moderate histopathologic changes were detected. Significant increases of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and IL-6 were observed after 24 hours (P < .01). The presented surfactant depletion-based lung injury model was associated with increased pulmonary inflammation and fulfilled the criteria of acute ling injury (ALI) for 24 hours. PMID:19337905

  6. Ventilator-Induced Lung Injury (VILI) in Acute Respiratory Distress Syndrome (ARDS): Volutrauma and Molecular Effects

    PubMed Central

    Carrasco Loza, R; Villamizar Rodríguez, G; Medel Fernández, N

    2015-01-01

    Acute Respiratory Distress Syndrome (ARDS) is a clinical condition secondary to a variety of insults leading to a severe acute respiratory failure and high mortality in critically ill patients. Patients with ARDS generally require mechanical ventilation, which is another important factor that may increase the ALI (acute lung injury) by a series of pathophysiological mechanisms, whose common element is the initial volutrauma in the alveolar units, and forming part of an entity known clinically as ventilator-induced lung injury (VILI). Injured lungs can be partially protected by optimal settings and ventilation modes, using low tidal volume (VT) values and high positive-end expiratory pressure (PEEP). The benefits in ARDS outcomes caused by these interventions have been confirmed by several prospective randomized controlled trials (RCTs) and are attributed to reduction in volutrauma. The purpose of this article is to present an approach to VILI pathophysiology focused on the effects of volutrauma that lead to lung injury and the ‘mechanotransduction’ mechanism. A more complete understanding about the molecular effects that physical forces could have, is essential for a better assessment of existing strategies as well as the development of new therapeutic strategies to reduce the damage resulting from VILI, and thereby contribute to reducing mortality in ARDS. PMID:26312103

  7. Acute Respiratory Failure in Critically Ill Patients with Interstitial Lung Disease

    PubMed Central

    Zafrani, Lara; Lemiale, Virginie; Lapidus, Nathanael; Lorillon, Gwenael; Schlemmer, Benoît; Azoulay, Elie

    2014-01-01

    Background Patients with chronic known or unknown interstitial lung disease (ILD) may present with severe respiratory flares that require intensive management. Outcome data in these patients are scarce. Patients and Methods Clinical and radiological features were collected in 83 patients with ILD-associated acute respiratory failure (ARF). Determinants of hospital mortality and response to corticosteroid therapy were identified by logistic regression. Results Hospital and 1-year mortality rates were 41% and 54% respectively. Pulmonary hypertension, computed tomography (CT) fibrosis and acute kidney injury were independently associated with mortality (odds ratio (OR) 4.55; 95% confidence interval (95%CI) (1.20–17.33); OR, 7.68; (1.78–33.22) and OR 10.60; (2.25–49.97) respectively). Response to steroids was higher in patients with shorter time from hospital admission to corticosteroid therapy. Patients with fibrosis on CT had lower response to steroids (OR, 0.03; (0.005–0.21)). In mechanically ventilated patients, overdistension induced by high PEEP settings was associated with CT fibrosis and hospital mortality. Conclusion Mortality is high in ILD-associated ARF. CT and echocardiography are valuable prognostic tools. Prompt corticosteroid therapy may improve survival. PMID:25115557

  8. Histopathological changes and mRNA expression in lungs of horses after inhalation anaesthesia with different ventilation strategies.

    PubMed

    Hopster, K; Jacobson, B; Hopster-Iversen, C; Rohn, K; Kästner, S B R

    2016-08-01

    Inappropriate mechanical ventilation can lead to ventilator-induced lung injury (VILI). Aim of this study was to evaluate the effects of inhalation anaesthesia and ventilation with and without recruitment (RM) and PEEP titration on alveolar integrity in horses. Twenty-three horses were divided into 4 groups (group OLC ventilated with OLC, group IPPV ventilated with intermittent positive pressure ventilation, group NV non-ventilated, and group C non-anaesthetized control group). After sedation with xylazine and induction with diazepam and ketamine anaesthetized horses were under isoflurane anaesthesia for 5.5h. The horses were euthanized and tissue samples of the dependent and non-dependent lung areas were collected. Histopathological examinations of the lung tissue as well as relative quantification of mRNA of IL-1β, IL-6, iNOS, MMP1 and MMP9 by PCR were performed. Horses of group OLC had significantly less alveolar congestion and atelectasis but greater alveolar overdistension compared to groups NV and IPPV. In groups OLC and group IPPV an increase in IL-1β/6 and MMP1/9 was detected compared to groups NV and C. In conclusion, in breathing spontaneously or IPPV-ventilated horses a higher degree of atelectasis was detected, whereas in OLC-ventilated horses a higher degree of overdistention was present. Elevated levels in IL and MMP might be early signs of VILI in ventilated horses. PMID:27473968

  9. Nanoporous Materials from ABAC Tetrablock Terpolymers

    NASA Astrophysics Data System (ADS)

    Jackson, Elizabeth Ashley

    This dissertation describes efforts towards the preparation of tough nanoporous membranes from ABAC tetrablock terpolymers. This architecture was strategically chosen to combine an etchable C block, PLA, with a mechanically tough ABA triblock into one ABAC terpolymer. Multiple series of poly(styrene- b-isoprene-b-styrene-b-lactide) (PS-PI-PS-PLA) tetrablock terpolymers were synthesized. Morphological behavior was characterized for terpolymers containing both a 50:50 and 30:70 PS:PI ratio with between 0 and ~20% PLA by volume. Observed bulk morphologies include hexagonally packed cylinders (HEX), core(PLA)-shell(PS) cylinders (CSC), and a PLA sphere in cylinder morphology. Mechanical properties of PS-PEEP-PS-PLA tetrablocks were also investigated. All materials exhibited mechanical properties characteristic of tough thermoplastic elastomers. Composite membranes were prepared from a thin film of PS-PI-PS-PLA terpolymer and a macroporous polyethersulfone support. Described within are the efforts related to the fabrication and filtration performance of these nanoporous PS-PI-PS composite membranes. As part of this process, solvent casting and annealing conditions were varied to investigate effects on tetrablock thin film morphology. Optimum conditions were determined to achieve PS-PI-PS-PLA films with perpendicular PLA cylinder orientation. These conditions included use of a mixed solvent system and the addition of a small amount of homopolymer PLA. Highly ordered films with vertically oriented nanopores were obtained.

  10. Ventilator-associated lung injury.

    PubMed

    Kuchnicka, Katarzyna; Maciejewski, Dariusz

    2013-01-01

    Mechanical ventilation of disease-affected lungs, as well as being an inadequate mode of ventilation for initially healthy lungs, can cause significant changes in their structure and function. In order to differentiate these processes, two terms are used: ventilator-associated lung injury (VALI) and ventilator-induced lung injury (VILI). In both cases, lung injury primarily results from differences in transpulmonary pressure - a consequence of an imbalance between lung stress and strain. This paper focuses on changes in lung structure and function due to this imbalance. Moreover, in this context, barotrauma, volutrauma and atelectrauma are interpreted, and the importance of signal transduction as a process inducing local and systemic inflammatory responses (biotrauma), is determined. None of the assessed methods of reducing VALI and VILI has been found to be entirely satisfactory, yet studies evaluating oscillatory ventilation, liquid ventilation, early ECMO, super-protective ventilation or noisy ventilation and administration of certain drugs are under way. Low tidal volume ventilation and adequately adjusted PEEP appear to be the best preventive measures of mechanical ventilation in any setting, including the operating theatre. Furthermore, this paper highlights the advances in VILI/VALI prevention resulting from better understanding of pathophysiological phenomena. PMID:24092514

  11. THE CHILD'S SEXUAL LIFE—A Consideration of Clinical Implications

    PubMed Central

    Teicher, Joseph D.

    1957-01-01

    A healthy sexual life begins in childhood, and the groundwork for later difficulties also begins in childhood. For the child, sexuality is a rather general, pleasurable excitation, not a specific genital stimulation. Excessive attention to the perineal area, operation upon or injury to the genital area and injections are vicissitudes which may have an unhealthy influence on later sexual development. Healthy and informed parental attitudes are the key here, just as they are in the normal exhibitionism, curiosity and intense emotional attachments to parents. Parents infect children, healthily or unhealthily, with their attitudes. In healthy growth exhibitionism and peeping become transformed in socially acceptable ways. In unhealthy growth, either perversions or strong reactions like over-modesty or shame result. Masturbation is common and transitory in most children. Parents, and especially pediatricians to whom parents turn, have a golden opportunity to direct healthy growth by being well informed about the infant and child's sexual growth and thus be enabled to advise upon or manage the common developmental phenomena with good commonsense and patience. Infants and children do not enter the world possessing the morals, standards or inhibitions of adults. PMID:13426800

  12. Dynamic Determination of Oxygenation and Lung Compliance in Murine Pneumonectomy

    PubMed Central

    Gibney, Barry; Lee, Grace S.; Houdek, Jan; Lin, Miao; Miele, Lino; Chamoto, Kenji; Konerding, Moritz A.; Tsuda, Akira; Mentzer, Steven J.

    2012-01-01

    Thoracic surgical procedures in mice have been applied to a wide range of investigations, but little is known about the murine physiologic response to pulmonary surgery. Using continuous arterial oximetry monitoring and the FlexiVent murine ventilator, we investigated the effect of anesthesia and pneumonectomy on mouse oxygen saturation and lung mechanics. Sedation resulted in a dose-dependent decline of oxygen saturation that ranged from 55–82%. Oxygen saturation was restored by mechanical ventilation with increased rate and tidal volumes. In the mouse strain studied, optimal ventilatory rates were a rate of 200/minute and a tidal volume of 10ml/kg. Sustained inflation pressures, referred to as a "recruitment maneuver," improved lung volumes, lung compliance and arterial oxygenation. In contrast, positive end expiratory pressure (PEEP) had a detrimental effect on oxygenation; an effect that was ameliorated after pneumonectomy. Our results confirm that lung volumes in the mouse are dynamically determined and suggest a threshold level of mechanical ventilation to maintain perioperative oxygen saturation. PMID:21574875

  13. A prophylactic fresh frozen plasma transfusion leads to a possible case of transfusion-related acute lung injury

    PubMed Central

    Banerjee, Debasree; Hussain, Rashid; Mazer, Jeffrey; Carino, Gerardo

    2014-01-01

    A 39-year-old man with cholangiocarcinoma presented with fever and abdominal pain. He was hypotensive, jaundiced and had right upper quadrant tenderness. Laboratory testing showed a leucocytosis, elevated liver function tests, total bilirubin and International Normalised Ratio (INR). Given the concern for cholangitis, the patient was given antibiotics and three units of fresh frozen plasma (FFP) before biliary drain placement. After drain placement, and within 3 h of receiving blood products, the patient became tachypnoeic and hypoxic with a chest X-ray revealing new bilateral airspace disease. The rapid development of respiratory distress was determined to most likely be transfusion-related acute lung injury (TRALI). He rapidly progressed to intubation and required 100% FiO2, high positive-end expiratory pressure (PEEP) and intermittent-prone ventilation for 48 h but eventually recovered and was extubated. TRALI is an under-recognised aetiology for respiratory distress in the critically ill. Adopting a conservative transfusion strategy may prevent TRALI. PMID:25053669

  14. [What Should We Know about Respiratory Physiology for the Optimal Anesthesia Management?].

    PubMed

    Ochiai, Ryoichi

    2016-05-01

    Gas exchange in the lungs is dependent on the balance between ventilation and pulmonary perfusion, and such balance could be modified and affected by various factors, including gravity, body position, physical property of the lung, and neurological as well as humoral factors. Oxygenation is the process where the oxygen molecule moves from alveoli to the blood plasma, and this process is highly dependent on the diffusion capacity. Although the oxygen partial pressure in the blood plasma at alveoli rises rapidly because of its very low solubility, hemoglobin is essential to maintain adequate oxygen content in the whole blood. When a part of the lung has atelectasis, pulmonary shunt and desaturation of arterial blood ensue. For the optimal patient care, atelectasis and pulmonary shunt should be taken care of well with thorough monitoring. Ventilation is the process where carbon dioxide (CO2) moves from blood plasma to alveoli, and can eliminate CO2, produced by metabolism. The understanding of ventilator-induced lung injury (VILI) during acute respiratory failure leads us to ventilate the lungs in less harmful way, with lung protective ventilation, and the most important factor is driving pressure (inspiratory plateau pressure-PEEP). When the ventilator setting should be adjusted in order to maintain adequate ventilation, the respiratory frequency is essential to adjust alveolar ventilation without affecting driving pressure. PMID:27319088

  15. Examining gender based violence and abuse among Liberian school students in four counties: An exploratory study.

    PubMed

    Postmus, Judy L; Hoge, Gretchen L; Davis, Rebecca; Johnson, Laura; Koechlein, Elizabeth; Winter, Samantha

    2015-06-01

    The purpose of this article is to uncover the extent of sexual gender based violence (GBV) experienced by a convenience sample of students from select counties in Liberia and to understand the disclosure experiences of those victims willing to come forward. Girls (n=758) and boys (n=1,100) were asked about their sexual GBV experiences including their disclosure experiences, if applicable. Results indicated that sexual violation (i.e., peeping or inappropriate touching) was found among both girls and boys. Sexual coercion (i.e., forced sex) was more prevalent than transactional sex (i.e., trading sex for grades or money). Both sexual coercion and transactional sex were reported by more girls than boys, yet the rates for the most severe form of sexual violence (i.e., sexual coercion) were high for both girls (30%) and boys (22%). When students were asked if they told anyone, 38% reported that they did disclose their experiences. This study contributes to a small but growing body of research to document the prevalence and types of sexual violence against children in Liberia. Consistent with other studies, the evidence shows that sexual violence against boys and girls is occurring at alarming rates. PMID:25529859

  16. Lung recruitment maneuvers using direct ultrasound guidance: a case study.

    PubMed

    Du, Jiang; Tan, Jiuting; Yu, Kanglong; Wang, Ruilan

    2015-05-01

    Previous studies have shown that lung recruitment maneuvers are important means of treating ARDS. Although computed tomography (CT) scans and pressure-volume curves are the most common ways to evaluate lung recruitment, there are still many disadvantages. Not only do the scans have to take place in a CT room, but the patient is exposed to large doses of radiation through the multiple scans necessary to define the optimal PEEP. Pressure-volume curves require deep sedation and muscle relaxation. Thus, bedside lung ultrasound may be considered to be a safer and easier alternative to CT scans or pressure-volume curves. In our case, we evaluated the effectiveness of lung recruitment with a bedside ultrasound on a patient who was suffering from life-threatening hypoxemia. Bedside ultrasound is a faster and more convenient imaging method because it reduces the need for patient transport compared with CT scan and requires no muscle relaxation. This case supports that ultrasound may become an alternative imaging tool to guide and evaluate alveolar recruitment in patients with ARDS. Additionally, we have also included a brief review of lung recruitment evaluation by ultrasound to supplement this case study. PMID:25406343

  17. Characterization of haemoglobin from actinorhizal plants--an in silico approach.

    PubMed

    Bhattacharya, Sanghati; Sen, Arnab; Thakur, Subarna; Tisa, Louis S

    2013-11-01

    Plant haemoglobins (Hbs), found in both symbiotic and non-symbiotic plants, are heme proteins and members of the globin superfamily. Hb genes of actinorhizal Fagales mostly belong to the non-symbiotic type of haemoglobin; however, along with the non-symbiotic Hb, Casuarina sp. posses a symbiotic one (symCgHb), which is expressed specifically in infected cells of nodules. A thorough sequence analysis of 26 plant Hb proteins, currently available in public domain, revealed a consensus motif of 29 amino acids. This motif is present in all the members of symbiotic class II Hbs including symCgHb and non-symbiotic Class II Hbs, but is totally absent in Class I symbiotic and non-symbiotic Hbs. Further, we constructed 3D structures of Hb proteins from Alnus and Casuarina through homology modelling and peeped into their structural properties. Structure-based studies revealed that the Casuarina symbiotic haemoglobin protein shows distinct stereochemical properties from that of the other Casuarina and Alnus Hb proteins. It also showed considerable structural similarities with leghemoglobin structure from yellow lupin (pdb id 1GDI). Therefore, sequence and structure analyses point to the fact that symCgHb protein shows significant resemblance to symbiotic haemoglobin found in legumes and may thus eventually play a similar role in shielding the nitrogenase from oxygen as seen in the case of leghemoglobin. PMID:24287657

  18. Cardiopulmonary effects of intermittent mandatory ventilation.

    PubMed

    Douglas, M E; Downs, J B

    1980-01-01

    IMV is a combination of spontaneous and mechanical ventilation. For numerous reasons, IMV is potentially more advantageous than conventional techniques. By maintaining spontaneous breathing, mechanical augmentation can be titrated to adjust alveolar minute ventilation levels to normal, thereby decreasing the incidence of respiratory alkalemia. There are major differences between the cardiopulmonary effects of IMV and conventional mechanical ventilation. Spontaneous inspiration decreases Ppl and results in better distribution of inspired gas, a better V/Q, and less physiological dead space. In addition, transmural filling pressures, venous return, and cardiac output are more normal than during conventional mechanical ventilation. Maintenance of spontaneous ventilation lowers mean Paw and pulmonary vascular resistance. If venous admixture occurs, it can be minimized by titrating PEEP. Thus, more effective therapy for hypoxemia is possible. If spontaneous breathing is to persist and be efective, work-of-breathing must be minimized. This can be accomplished best when a continuous flow of gas provides optimal CPAP to maintain FRC and to minimize the effects of decreased compliance without depressing cardiac function. PMID:7007253

  19. Neonatal Intensive Care Units Nurses’ Attitude Toward Advantages and Disadvantages of Open vs Closed Endotracheal Suction

    PubMed Central

    Valizadeh, Leila; Janani, Raheleh; Janani, Leila; Galechi, Fatemeh

    2014-01-01

    Background: The vital issue of protecting the airway and maintaining ventilation in preterm infants makes tracheal suctioning an important procedure. The decision to use closed or open endotracheal suction method depends on the clinical status of infants and the nurses’ skills and preferences. Objectives: The current study aimed to compare the two methods based on the perceptions of the nurses working in Neonatal Intensive Care Units (NICU). Patients and Methods: A comparative-descriptive study carried out on 35 NICU nurses in Taleghani and Al-Zahra teaching hospitals in Tabriz, Iran, in 2013. Data were collected by self-administered questionnaire (13 Items). Data analysis, including t-test was performed using SPSS Ver. 13. A P ≤ 0.05 was considered statistically sig­nificant. Results: According to the nurses’ point of view, there are differences between characteristics of open and closed endotracheal suctioning methods (P < 0.001). By using closed endotracheal suction, the risk of traumatizing airway, developing pneumonia, increasing intracranial pressure, prolonging emergency suctioning, developing intra-ventricular hemorrhage, blood stream infection, physiological instability and lowering positive end-expiratory pressure (PEEP) are reduced. Meanwhile, lower cost, lower risk of extubation, comfort and easy washing procedure were reported as advantages of open suction. Conclusion: Closed endotracheal suctioning was evaluated to be better than the open method in the preterm neonates. More studies, especially experimental and efficient cost analysis, are recommended. PMID:25414901

  20. pp iii The importance of high-resolution monitoring in erosion and deposition dynamics studies: examples from estuarine and fluvial systems

    NASA Astrophysics Data System (ADS)

    Lawler, D. M.

    2005-01-01

    Erosion and deposition processes lie at the centre of geomorphological explanation, but progress in understanding has been limited by a lack of appropriate high-resolution monitoring methodologies which permit detection of erosion and deposition dynamics. This paper presents a case for monitoring erosion and deposition at high temporal resolutions, and uses hypothetical approaches supported by example erosion and deposition events and analyses drawn from estuarine and fluvial systems. The paper first presents testable hypotheses to demonstrate the complexity of possible event combinations, sequences and juxtapositions for the erosion driving forces which underpin the need for high-resolution monitoring. Second, it summarises recent improvements to the Photo-Electronic Erosion Pin (PEEP) automatic erosion and deposition monitoring system, including the novel concept of Thermal Consonance Timing (TCT), which is particularly promising because it helps to define the timing of nocturnal events and through the entire hydrograph. Third, example results are discussed from high-resolution monitoring of bank erosion at a tidal site at Burringham on the River Trent in northern England. Tidal banks are revealed to be much more dynamic than previous conventional monitoring has indicated. A key result is that, because the high-resolution approach allows erosional and depositional activity to be assigned to specific periods of tidal inundation, it becomes possible for the first time routinely to produce 'event-based' erosion (36 mm h -1) and deposition rates (4.5 and 8.4 mm h -1). Such rate determinations are potentially very useful in the field validation of sedimentological and geomorphological models, including grain settling and resuspension theory. Fourth, through a longer term of aggregated daily data, a striking 2-week cycle of deposition and erosion emerges which correlates most strongly with spring-neap tidal cycling, but is moderated by wind stress effects. Sediment was

  1. History and current status of mini-invasive thoracic surgery

    PubMed Central

    He, Jianxing

    2011-01-01

    Mini-invasive thoracic technique mainly refers to a technique involving the significant reduction of the chest wall access-related trauma. Notably, thoracoscope is the chief representative. The development of thoracoscope technique is characterized by: developing from direct peep to artificial lighting, then combination with image and video technique in equipments; technically developing from diagnostic to therapeutic approaches; developing from simpleness to complexity in application scope; and usually developing together with other techniques. At present, the widely used mini-invasive thoracic surgery refers to the mini-open thoracic surgery performed mainly by using some instruments to control target tissues and organs based on the vision associated with multi-limb coordination, which may be hand-assisted if necessary. The mini-invasive thoracic surgery consists of three approaches including video-assisted thoracic surgery (VATS), video-assisted Hybrid and hand-assisted VATS. So far the mini-invasive thoracic technique has achieved great advances due to the development in instruments of mini-invasive thoracic surgery which has the following features: instruments of mini-invasive thoracic surgery appear to be safe and practical, and have successive improvement and diversification in function; the specific instruments of open surgeries has been successively developed into dedicated instruments of endoscopic surgery; the application of endoscopic mechanical suture device generates faster fragmentation and reconstruction of organ tissues; the specific delicated instruments of endoscopic surgery have rapid development and application; and the simple instruments structurally similar to the conventional instruments are designed according to the mini-incison. In addition, the mini-invasive thoracic technique is widely used in five aspects including diseases of pleura membrane and chest wall, lung diseases, esophageal diseases, mediastinal diseases and heart diseases

  2. Effectiveness of Inspiratory Termination Synchrony with Automatic Cycling During Noninvasive Pressure Support Ventilation.

    PubMed

    Chen, Yuqing; Cheng, Kewen; Zhou, Xin

    2016-01-01

    BACKGROUND Pressure support ventilation (PSV) is a standard method for non-invasive home ventilation. A bench study was designed to compare the effectiveness of patient-ventilator inspiratory termination synchronization with automated and conventional triggering in various respiratory mechanics models. MATERIAL AND METHODS Two ventilators, the Respironics V60 and Curative Flexo ST 30, connected to a Hans Rudolph Series 1101 lung simulator, were evaluated using settings that simulate lung mechanics in patients with chronic obstructive pulmonary disease (COPD), acute respiratory distress syndrome (ARDS), or normal lungs. Ventilators were operated with automated (Auto-Trak) or conventional high-, moderate-, and low-sensitivity flow-cycling software algorithms, 5 cmH2O or 15 cmH2O pressure support, 5 cmH2O positive end-expiratory pressure (PEEP), and an air leak of 25-28 L/min. RESULTS Both ventilators adapted to the system leak without requiring adjustment of triggering settings. In all simulated lung conditions, automated cycling resulted in shorter triggering delay times (<100 ms) and lower triggering pressure-time product (PTPt) values. Tidal volumes (VT) increased with lower conventional cycling sensitivity level. In the COPD model, automated cycling had higher leak volumes and shorter cycling delay times than in conventional cycling. Asynchronous events were rare. Inspiratory time (Tinsp), peak expiratory flow (PEF), and cycling off delay time (Cdelay) increased as a result of reduction in conventional cycling sensitivity level. In the ARDS and normal adult lung models, premature cycling was frequent at the high-sensitive cycling level. CONCLUSIONS Overall, the Auto-Trak protocol showed better patient-machine cycling synchronization than conventional triggering. This was evident by shorter triggering time delays and lower PTPt. PMID:27198165

  3. Improving donor lung suitability: from protective strategies to ex-vivo reconditioning.

    PubMed

    Solidoro, Paolo; Schreiber, Annia; Boffini, Massimo; Braido, Fulvio; DI Marco, Fabiano

    2016-06-01

    Lung transplant is a therapeutic option for end stage lung diseases, but only a limited number of lung grafts is considered suitable for transplantation. It has been recently suggested an approach to improve and maximize donor lung suitability, namely ventilation strategies to prevent lung damage and preserve function before transplantation. In potential lung donor patients, the use of lung-protective ventilatory strategies may protect against and at least partially reverse some conditions, such as ventilator-induced lung injury, atelectasis and neurogenic pulmonary edema, resulting in improved donor organ procurement. The novelty recently proposed lies in the integration of ventilatory strategies of previous studies, using an algorithmic approach for the management of potential donors, based on their clinical response and PaO2/FiO2 ratio. This approach could be further improved by using lung ultrasound (LUS) which demonstrated to be more accurate than bedside chest radiography in detecting and distinguishing different degrees of aeration loss, and could be useful in the evaluation of alveolar recruitment following the application of PEEP or after performing any recruitment maneuver. Finally, the close future is the exploration of ex-vivo reconditioning which introduces the exciting concept of both a protective ventilation and a protective perfusion, reducing the risk of ventilation associated damage, and, on the other hand, washing out potential inflammatory cytokines by low volume high oncotic pressure perfusion, managing the risk of edema by capillary leakage. Addressing these challenges will allow more patients with end-stage lung disease access to a lung transplant. PMID:27424500

  4. [Use of microstream capnography and alveolar recruitment during off-pump coronary artery bypass grafting].

    PubMed

    Suborov, E V; Postnikova, E A; Kapinos, A A; Kuz'kov, V V; Smetkin, A A; Kirov, M Iu

    2009-01-01

    The aim of the study was to investigate changes in EtCO2 and its correlation with PaCO2, and cardiac function during off-pump coronary artery bypass grafting (OPCAB) and to evaluate whether the recruitment maneuver was effective in improving gas exchange after OPCAB. Twenty adult patients scheduled for elective OPCAB were enrolled in a prospective randomized study. Anesthesia was maintained with midazolam, propofol, and fentanyl. After OPCAB the patients were randomized to a control group receiving conventional ventilation (n=10) or to a RM group (n=10) having ventilation and RM. RM was performed at min 15 after transfer to an ICU, by increasing airway pressure to 40 cm H2O for 40 sec subsequently adjusting PEEP to a level of 2 cm H2O above the lower inflection point of the pressure-volume curve. The measurements included hemodynamics, microstream capnography, respiratory parameters, and blood gasses. The baseline EtCO2 correlated with PaCO2 and cardiac index in both group (r = 0.7 and 0.81, respectively; p < 0.05). In the control group, OPCAB was followed by a rise in PaCO2 and worsening of arterial oxygenation (p < 0.05). After recruitment, EtCO, increased transiently whereas PaO2/FiO2 return to the baseline level. There was a moderate correlation between EtCO2 and PaCO2 before and after RM (r = 0.7 and 0.8, respectively; p < 0.05). The Bland-Altman analysis has shown that the difference between PaCO2 an EtCO2 was 1.9 +/- 11.4 mm Hg (M +/- 2SD). Thus, during OPCAB, EtCO2 measured by microstream capnography cor related well with PaCO2 and cardiac function. The use of RM after OPCAB increases CO2 elimination and improve arterial oxygenation. PMID:19824412

  5. Application of CO2 waveform in the alveolar recruitment maneuvers of hypoxemic patients during one-lung ventilation.

    PubMed

    Dong, Chunshan; Yu, Junma; Liu, Qi; Wu, Chao; Lu, Yao

    2016-06-01

    Deterioration of gas exchange during one-lung ventilation (OLV) is caused by both total collapse of the nondependent lung and partial collapse of the dependent lung. Alveolar recruitment maneuver improves lung function during general anesthesia. The objective of this study was to investigate whether there is an indirect relationship between the changes of CO2 expirogram and the selective lung recruitment. To further improve the oxygenation and gas exchange, we compare adjust setting of ventilated parameters based on CO2 expirogram and a preset setting of ventilated parameters during OLV in patients undergoing right-side thoracic surgery.Thirty patients met the requirements criteria that were studied at 3 time points: during two-lung ventilation (TLV), during OLV with preset ventilation parameters (OLV-PP), and during OLV with adjustable ventilation parameters (OLV-AP) that are in accordance with CO2 expirogram. Adjustable ventilation parameters such as tidal volume (VT), respiratory rate (RR), positive end-expiratory pressure (PEEP), and the ratio of inspiratory to expiratory were adjusted by utilizing the phase III slopes of CO2 expirogram, which together with the relationship between the changes of CO2 expirogram and the selective lung recruitment.During OLV, the phase III slopes of CO2 expirogram in patients with pulse oxymetry (SpO2) decreased less than 93% after the OLV-PP, and were absolutely different from that during TLV. After OLV-AP, the phase III slopes of CO2 expirogram and SpO2 were similar to those during TLV. During OLV, however, parameters of ventilation setting in both OLV-PP and OLV-AP are obviously different.This study indicates that alveolar recruitment by utilizing CO2 expirogram probably improves SpO2 level during one-lung ventilation. PMID:27310989

  6. Distending Pressure Did Not Activate Acute Phase or Inflammatory Responses in the Airways and Lungs of Fetal, Preterm Lambs

    PubMed Central

    Petersen, Rebecca Y.; Royse, Emily; Kemp, Matthew W.; Miura, Yuichiro; Noe, Andres; Jobe, Alan H.; Hillman, Noah H.

    2016-01-01

    Background Mechanical ventilation at birth causes airway injury and lung inflammation in preterm sheep. Continuous positive airway pressure (CPAP) is being increasingly used clinically to transition preterm infants at birth. Objective To test if distending pressures will activate acute phase reactants and inflammatory changes in the airways of fetal, preterm lambs. Methods The head and chest of fetal lambs at 128±1 day GA were surgically exteriorized. With placental circulation intact, fetal lambs were then randomized to one of five 15 minute interventions: PEEP of 0, 4, 8, 12, or 16 cmH2O. Recruitment volumes were recorded. Fetal lambs remained on placental support for 30 min after the intervention. The twins of each 0 cmH2O animal served as controls. Fetal lung fluid (FLF), bronchoalveolar lavage fluid (BAL), right mainstem bronchi and peripheral lung tissue were evaluated for inflammation. Results Recruitment volume increased from 0.4±0.04 mL/kg at 4 cmH2O to 2.4±0.3 mL/kg at 16 cmH2O. The lambs were surfactant deficient, and all pressures were below the opening inflection pressure on pressure-volume curve. mRNA expression of early response genes and pro-inflammatory cytokines did not increase in airway tissue or lung tissue at any pressure compared to controls. FLF and BAL also did not have increases in early response proteins. No histologic changes or Egr-1 activation was present at the pressures used. Conclusion Distending pressures as high as 16 cmH2O did not recruit lung volume at birth and did not increase markers of injury in the lung or airways in non-breathing preterm fetal sheep. PMID:27463520

  7. Efficacy of noninvasive CPAP in COPD with acute respiratory failure.

    PubMed

    Goldberg, P; Reissmann, H; Maltais, F; Ranieri, M; Gottfried, S B

    1995-11-01

    Dynamic hyperinflation and the development of intrinsic positive end-expiratory pressure (PEEPi) are commonly observed in patients with severe chronic obstructive pulmonary disease (COPD) in acute respiratory failure. Previous studies have shown that externally applied PEEP reduces PEEPi and its adverse effects in mechanically-ventilated COPD patients. The purpose of this study was to determine the effects of graded amounts of continuous positive airway pressure (CPAP) on the degree of inspiratory effort, pattern of breathing, gas exchange, and level of dyspnoea in a group of spontaneously breathing, nonintubated COPD patients in acute hypercapnic respiratory failure. Ten COPD patients admitted to the intensive care unit in acute hypercapnic respiratory failure were studied. Inspiratory effort was measured by the tidal excursions of oesophageal (Poes) and transdiaphragmatic (Pdi) pressure. Inspiratory effort and both the pressure-time product for the diaphragm (integral of Pdi-dt) and for the inspiratory muscles (integral of Poes.dt) were measured during the application of 5, 7.5, and 10 cmH2O of CPAP. Dyspnoea, gas exchange and pattern of breathing were also assessed. Inspiratory effort and the pressure-time product both for the diaphragm and the inspiratory muscles fell significantly with CPAP in a dose-dependent fashion. Both the pattern of breathing and level of dyspnoea improved with CPAP. End-expiratory lung volume remained stable at the lower levels of CPAP, with only modest increases at the higher levels. Arterial oxygen tension (Pa,O2) and arterial carbon dioxide tension (Pa,CO2) either improved or remained stable with CPAP. We conclude that the noninvasive application of CPAP to spontaneously breathing patients with severe COPD in acute respiratory failure decreases inspiratory effort and dyspnoea whilst improving breathing pattern. It is conceivable that the early institution of CPAP in this setting may obviate the need for intubation and conventional

  8. The physiologic meaning of the respiratory index in various types of critical illness.

    PubMed

    Sganga, G; Siegel, J H; Coleman, B; Giovannini, I; Boldrini, G; Pittiruti, M

    1985-01-01

    Seven hundred and sixty cardiorespiratory studies, from 151 critically ill or high-risk general surgical patients with extrapulmonary (S) or pulmonary (P) sepsis, cirrhotic liver disease (L), or cardiac failure (C), were analyzed to assess the determinants of a simple, easily obtained measure of respiratory oxygen exchange, the respiratory index (RI). The pattern of cardiorespiratory abnormalities was studied and correlated with the change in RI. The most important relations were with shunt (QS/QT), mixed venous O2 (PvO2), VD, and VE. Higher F1O2 and positive end-expiratory pressure (PEEP) were needed as the RI rose, indicating a greater severity of illness. Regression analysis of all types of critically ill patients and surgical controls showed that QS/QT, PvO2, and F1O2 interacted together to explain most of the variability of the RI. The regressions in each homogeneous patient disease category were all highly significant (p less than .0001) but had somewhat similar coefficients and explained the variability in RI to different degrees. The data suggest that patients with extrapulmonary sepsis or cirrhotic liver disease have an increase in RI (over that in controls) primarily due to a large increase in CI at the high QS/QT caused by the ventilation/perfusion (VA/QT) maldistribution characteristic of these diseases. However, patients with P or C have a disproportionate rise in RI at any given QS/QT compared to that in high-flow states alone, suggesting in P a direct alveolar limitation of oxygen exchange over and above any level of VA/QT mismatching, and suggesting in C a disproportionate decrease in PvO2 that magnifies the QS/QT effect even though VA/QT is more uniform. PMID:4075505

  9. USE OF POSITIVE PRESSURE IN THE BARIATRIC SURGERY AND EFFECTS ON PULMONARY FUNCTION AND PREVALENCE OF ATELECTASIS: RANDOMIZED AND BLINDED CLINICAL TRIAL

    PubMed Central

    BALTIERI, Letícia; SANTOS, Laisa Antonela; RASERA-JUNIOR, Irineu; MONTEBELO, Maria Imaculada Lima; PAZZIANOTTO-FORTI, Eli Maria

    2014-01-01

    Background In surgical procedures, obesity is a risk factor for the onset of intra and postoperative respiratory complications. Aim Determine what moment of application of positive pressure brings better benefits on lung function, incidence of atelectasis and diaphragmatic excursion, in the preoperative, intraoperative or immediate postoperative period. Method Randomized, controlled, blinded study, conducted in a hospital and included subjects with BMI between 40 and 55 kg/m2, 25 and 55 years, underwent bariatric surgery by laparotomy. They were underwent preoperative and postoperative evaluations. They were allocated into four different groups: 1) Gpre: treated with positive pressure in the BiPAP mode (Bi-Level Positive Airway Pressure) before surgery for one hour; 2) Gpos: BIPAP after surgery for one hour; 3) Gintra: PEEP (Positive End Expiratory Pressure) at 10 cmH2O during the surgery; 4) Gcontrol: only conventional respiratory physiotherapy. The evaluation consisted of anthropometric data, pulmonary function tests and chest radiography. Results Were allocated 40 patients, 10 in each group. There were significant differences for the expiratory reserve volume and percentage of the predicted expiratory reserve volume, in which the groups that received treatment showed a smaller loss in expiratory reserve volume from the preoperative to postoperative stages. The postoperative radiographic analysis showed a 25% prevalence of atelectasis for Gcontrol, 11.1% for Gintra, 10% for Gpre, and 0% for Gpos. There was no significant difference in diaphragmatic mobility amongst the groups. Conclusion The optimal time of application of positive pressure is in the immediate postoperative period, immediately after extubation, because it reduces the incidence of atelectasis and there is reduction of loss of expiratory reserve volume. PMID:25409961

  10. A comparative study of the effects of morphine in the dorsal periaqueductal gray and nucleus accumbens of rats submitted to the elevated plus-maze test.

    PubMed

    Anseloni, V C; Coimbra, N C; Morato, S; Brandão, M L

    1999-11-01

    We studied the effects of morphine injected either systemically or into the dorsal periaqueductal gray (DPAG) or nucleus accumbens (NA) using conventional and ethological analyses of behavior of rats submitted to the elevated plus-maze test with transparent walls. Intraperitoneal morphine (0.1 mg/kg and 0.3 mg/kg) increased both standard and ethological measures, expressing general exploratory activity such as total arm entries, end-exploration, scanning, head-dipping, and rearing. Morphine 10 (7.6 microg/microl) and 30 nmol (23 microg/microl) injected into nucleus accumbens produced similar effects, which were blocked by i.p. naltrexone (2.0 mg/kg), an opioid antagonist with good affinity for mu-opioid receptors. Morphine injected into the DPAG produced either antiaversive (10 nmol) or aversive effects (30 nmol), which respectively reduced and increased entries and time spent in the open arms and behaviors associated with risk assessment (peeping out, stretched attend postures, and flat back approach). The proaversive effects were inhibited by i.p. norbinaltorphimine (2.0 mg/kg), a selective inhibitor for kappa-opioid receptors. These findings support the contention that at least some of the motivational effects of morphine may be due to activation of opioid mechanisms in nucleus accumbens, and DPAG has neural substrates for antiaversive and aversive effects of morphine. Moreover, on the basis of previous and present data obtained in this laboratory, it is suggested that stimulation of mu-opioid receptors inhibits and stimulation of kappa-receptors activates the neural substrate of aversion in the DPAG. On the other hand, the increase in exploratory behavior due to interaction of morphine with mu-opioid receptors in the nucleus accumbens may be due to the stimulation of the interface between neural substrates of motivation and motor output in this structure. PMID:10591900

  11. An Improvised “Blow Glove” Device Produces Similar PEP Values to a Commercial PEP Device: An Experimental Study

    PubMed Central

    Dagan, Yaakov; Wiser, Itay; Farber, Nimrod; Hundeshagen, Gabriel; Winkler, Eyal; Kazula-Halabi, Tamar; Haik, Josef

    2014-01-01

    ABSTRACT Background: Postoperative positive expiratory pressure (PEP) therapy promotes increased lung volume, secretion clearance, and improved oxygenation. Several commercial devices exist that produce recommended PEP values (10–20 cmH2O) when the patient breathes through a fixed orifice resistor. It was hypothesized that an inexpensive, improvised “blow glove” device would produce similar PEP values over a wider range of expiration volumes and flow rates. Methods: PEP for different expiration volumes (400–2000 mL) and expiratory flow rates (10–80 L/min) was compared between a commercial PEP device (Resistex, Mercury Medical, Clearwater, FL) and an improvised “blow glove” device, recorded by a Vela ventilator (CareFusion, San Diego, CA). Dynamics in positive end expiratory pressure (PEEP) values were evaluated following five consecutive expirations. The “blow glove” device was evaluated using various glove compositions and sizes. Results: The improvised “blow glove” device produced a significantly higher rate of PEP values in the recommended range than the Resistex device (88.9% vs. 20%, p<0.0001). No significant difference was observed between small and large glove sizes (88.9% vs. 82.9%, p>0.05), but the powdered latex glove showed a significantly higher rate of PEP values in the recommended range than the powder-free latex glove (88.9% vs. 44.4%, p<0.001). Conclusions: A “blow glove” PEP device using a powdered latex glove produces PEP values in the recommended range over a wider spectrum of expiratory flow rates and expiration volumes than a commercial PEP device. PMID:25125786

  12. Thomas L Petty's lessons for the respiratory care clinician of today.

    PubMed

    Pierson, David J

    2014-08-01

    Because of the importance of his original contributions and their practical relevance today, Thomas L Petty (1932-2009) was arguably the most important physician in the history of respiratory care. As much as any single individual, he was responsible for the concept of intensive and multidisciplinary respiratory care. In the 1960s and 1970s, he made key observations and introduced pioneering therapies in the ICU and in the home. He was the first to describe and name ARDS and to show how to use PEEP to treat life-threatening hypoxemia. He was one of the first anywhere to organize a pulmonary rehabilitation program and to show the beneficial effects of long-term oxygen therapy in COPD. Dr Petty emphasized the importance of practical, hands-on respiratory care education for both physicians and non-physicians using a collaborative team approach. He targeted educational activities and practical resources specifically to patients, and he showed how researchers and clinicians could interact responsibly with innovators in industry to the benefit of both. His life and career provide 6 important lessons for respiratory clinicians today and in the future: (1) whatever their roles, RTs and other clinicians in this field need to be experts in its core areas, such as mechanical ventilation, ARDS, and COPD; (2) respiratory care is a team activity: every member is important, and all the members need to communicate well and work together; (3) education needs to be targeted to those in the best position to benefit the patient, including primary care providers and family members; (4) everyone in the field needs to understand the important role of the respiratory care industry and to deal with it responsibly; (5) it must never be forgotten that it is all about the patient; and (6) respiratory care should be exciting and fun. PMID:25233517

  13. Effectiveness of Inspiratory Termination Synchrony with Automatic Cycling During Noninvasive Pressure Support Ventilation

    PubMed Central

    Chen, Yuqing; Cheng, Kewen; Zhou, Xin

    2016-01-01

    Background Pressure support ventilation (PSV) is a standard method for non-invasive home ventilation. A bench study was designed to compare the effectiveness of patient-ventilator inspiratory termination synchronization with automated and conventional triggering in various respiratory mechanics models. Material/Methods Two ventilators, the Respironics V60 and Curative Flexo ST 30, connected to a Hans Rudolph Series 1101 lung simulator, were evaluated using settings that simulate lung mechanics in patients with chronic obstructive pulmonary disease (COPD), acute respiratory distress syndrome (ARDS), or normal lungs. Ventilators were operated with automated (Auto-Trak) or conventional high-, moderate-, and low-sensitivity flow-cycling software algorithms, 5 cmH2O or 15 cmH2O pressure support, 5 cmH2O positive end-expiratory pressure (PEEP), and an air leak of 25–28 L/min. Results Both ventilators adapted to the system leak without requiring adjustment of triggering settings. In all simulated lung conditions, automated cycling resulted in shorter triggering delay times (<100 ms) and lower triggering pressure-time product (PTPt) values. Tidal volumes (VT) increased with lower conventional cycling sensitivity level. In the COPD model, automated cycling had higher leak volumes and shorter cycling delay times than in conventional cycling. Asynchronous events were rare. Inspiratory time (Tinsp), peak expiratory flow (PEF), and cycling off delay time (Cdelay) increased as a result of reduction in conventional cycling sensitivity level. In the ARDS and normal adult lung models, premature cycling was frequent at the high-sensitive cycling level. Conclusions Overall, the Auto-Trak protocol showed better patient-machine cycling synchronization than conventional triggering. This was evident by shorter triggering time delays and lower PTPt. PMID:27198165

  14. Model-Based Prediction of the Patient-Specific Response to Adrenaline

    PubMed Central

    Chase, J. Geoffrey; Starfinger, Christina; Hann, Christopher E; Revie, James A; Stevenson, Dave; Shaw, Geoffrey M; Desaive, Thomas

    2010-01-01

    A model for the cardiovascular and circulatory systems has previously been validated in simulated cardiac and circulatory disease states. It has also been shown to accurately capture the main hemodynamic trends in porcine models of pulmonary embolism and PEEP (positive end-expiratory pressure) titrations at different volemic levels. In this research, the existing model and parameter identification process are used to study the effect of different adrenaline doses in healthy and critically ill patient populations, and to develop a means of predicting the hemodynamic response to adrenaline. The hemodynamic effects on arterial blood pressures and stroke volume (cardiac index) are simulated in the model and adrenaline-specific parameters are identified. The dose dependent changes in these parameters are then related to adrenaline dose using data from studies published in the literature. These relationships are then used to predict the future, patient-specific response to a change in dose or over time periods from 1-12 hours. The results are compared to data from 3 published adrenaline dosing studies comprising a total of 37 data sets. Absolute percentage errors for the identified model are within 10% when re-simulated and compared to clinical data for all cases. All identified parameter trends match clinically expected changes. Absolute percentage errors for the predicted hemodynamic responses (N=15) are also within 10% when re-simulated and compared to clinical data. Clinically accurate prediction of the effect of inotropic circulatory support drugs, such as adrenaline, offers significant potential for this type of model-based application. Overall, this work represents a further clinical, proof of concept, of the underlying fundamental mathematical model, methods and approach, as well as providing a template for using the model in clinical titration of adrenaline in a decision support role in critical care. They are thus a further justification in support of upcoming

  15. Estimation of endothelin-mediated vasoconstriction in acute pulmonary thromboembolism

    PubMed Central

    Tsang, John Y. C.; Lamm, Wayne J. E.

    2012-01-01

    We aimed to investigate the role of endothelin-mediated vasoconstriction following acute pulmonary thromboembolism (APTE). Thirteen anesthetized piglets (~25 kg) were ventilated with 0 PEEP. Cardiac output (Qt) and wedge pressure (Pw) were measured by a Swan Ganz catheter, along with arterial and venous blood gases. APTE was induced by autologous blood clots (~0.8 g/kg, 12-16 pieces) via a jugular venous catheter at time = 0 minutes until the mean pulmonary arterial pressure (Ppa) was about 2.5 times the baseline at 30 minutes. Eight control animals (Group 1) received only normal saline afterward, while the remaining five (Group 2) received at time = 40-minute saline plus Tezosentan, a nonspecific endothelin antagonist. The drug was initially given as an intravenous bolus (10 mg/kg), followed by an infusion (2 mg/min) until the end of the experiment at 2 hours. Hemodynamic data were measured before APTE and then at 30-minute intervals. Pulmonary vascular resistance index (PVRI) was calculated as (Ppa-Pw)/CI, where CI was cardiac index or Qt/W (body weight). Fluorescent microspheres (FMS) were used to mark regional blood flows and ventilation for cluster analysis. PVRI acutely increased within minutes and remained high despite some recovery over time. With Tezosentan treatment, the results showed that endothelin-mediated vasoconstriction persisted significantly up to 2 hours and accounted for about 25% of the increase in PVRI while clot obstruction accounted for the remaining 75%. CI remained relatively constant throughout. Tezosentan also affected PVRI indirectly by mitigating the shift of regional blood flow back to the embolized areas over time, possibly by attenuating vasoconstriction in the nonembolized areas. We conclude that following APTE, although the increased PVRI is mostly due to mechanical embolic obstruction, secondary factors such as vasoconstriction and pattern of regional blood flow over time also play important roles. PMID:22558522

  16. The idiot's dreams: rêverie in child psychotherapy.

    PubMed

    Arfelli, Patrizia

    2008-03-01

    When exploring the frontier of the "border" cases, that is treating severely damaged patients, either by organic pathologies or by severe physical traumas or even by catastrophic emotional events, the classical technique is often forsaken to pioneer new trails, and we may utilize intersubjective actions. Some of these actions may occur very directly and suddenly, only later revealing their meaning in the après coup; others, on the contrary, may be the result of a not always easy or painless choice; in either case, these actions can have a great therapeutic meaning. I ventured to follow one such trail, together with the child I am going to speak of in this paper: the little "idiot" (as he used to name himself). He was suffering from an extremely severe phonologic disorder, which allowed him to utter only inarticulate noises; yet, a rich and deep internal world peeped out in the sessions, a world imprisoned but not completely annihilated by mutism. For many months, I have been trying to lend my voice to this world, by agreeing to narrate "my own" dreams within the play that was taking place in the sessions: in other words, I have tried to make use of my rêverie and capacity of identification in order to express the awful anxieties connected with the child's impossibility to communicate and to be understood: that is, with his huge loneliness. This work of "translation" did not take place with interpretation dresses, but as a repeated narration of dreams and nightmares, apparently mine yet, actually, deeply belonging to him. In this way a first step has been taken towards the raise of trust and hope of being understood, an indispensable requirement for him to finally get-after many years of work-to express himself and to make himself understood. PMID:18301373

  17. Decision making in interhospital transport of critically ill patients: national questionnaire survey among critical care physicians

    PubMed Central

    de Vos, Rien; Binnekade, Jan M.; de Haan, Rob; Schultz, Marcus J.; Vroom, Margreeth B.

    2008-01-01

    Objective This study assessed the relative importance of clinical and transport-related factors in physicians' decision-making regarding the interhospital transport of critically ill patients. Methods The medical heads of all 95 ICUs in The Netherlands were surveyed with a questionnaire using 16 case vignettes to evaluate preferences for transportability; 78 physicians (82%) participated. The vignettes varied in eight factors with regard to severity of illness and transport conditions. Their relative weights were calculated for each level of the factors by conjoint analysis and expressed in β. The reference value (β = 0) was defined as the optimal conditions for critical care transport; a negative β indicated preference against transportability. Results The type of escorting personnel (paramedic only: β = –3.1) and transport facilities (standard ambulance β = –1.21) had the greatest negative effect on preference for transportability. Determinants reflecting severity of illness were of relative minor importance (dose of noradrenaline β = –0.6, arterial oxygenation β = –0.8, level of peep β = –0.6). Age, cardiac arrhythmia, and the indication for transport had no significant effect. Conclusions Escorting personnel and transport facilities in interhospital transport were considered as most important by intensive care physicians in determining transportability. When these factors are optimal, even severely critically ill patients are considered able to undergo transport. Further clinical research should tailor transport conditions to optimize the use of expensive resources in those inevitable road trips. PMID:18283432

  18. Antidepressant-like activity of EMD 386088, a 5-HT6 receptor partial agonist, following systemic acute and chronic administration to rats.

    PubMed

    Jastrzębska-Więsek, Magdalena; Siwek, Agata; Partyka, Anna; Szewczyk, Bernadeta; Sowa-Kućma, Magdalena; Wasik, Anna; Kołaczkowski, Marcin; Wesołowska, Anna

    2015-10-01

    The study was designed to examine the potency of EMD 386088, a 5-HT6 receptor partial agonist, to exert antidepressant-like properties in animal models following acute and chronic intraperitoneal administration to rats. The modified rat forced swim test (FST) was utilized to examine a potential antidepressant effect of EMD 386088 after acute treatment (30 min before the test) and three times in a 24-h administration scheme (24 h, 5 h, and 30 min prior to the FST). The olfactory bulbectomy (OB) model was used to assess its antidepressant-like properties after chronic treatment (the drug was administered once daily for 14 days). EMD 386088 showed an antidepressant-like effect in all conducted tests. Its activity in FST after its acute administration (5 mg/kg) was blocked by the selective 5-HT6 receptor antagonist SB 271046. The obtained results seem to be specific, as there was no observed locomotor stimulation by the drug given at a lower/antidepressant dose. In the three times in the 24-h treatment scheme, EMD 386088 (2.5 mg/kg) exerted antidepressant properties in FST as well as increased locomotor activity in the open field test. Chronic administration of EMD 386088 (2.5 mg/kg) significantly improved the learning deficit in OB rats without affecting performance in Sham-operated (SH) animals in the passive avoidance test, and reduced OB-related rats' locomotor hyperactivity, but did not change the number of rearing + peeping episodes. The obtained findings suggest that EMD 386088 produces antidepressant-like activity after systemic acute and chronic administration which may result from direct stimulation of 5-HT6 receptors. PMID:26077660

  19. Acute chlorine gas exposure produces transient inflammation and a progressive alteration in surfactant composition with accompanying mechanical dysfunction.

    PubMed

    Massa, Christopher B; Scott, Pamela; Abramova, Elena; Gardner, Carol; Laskin, Debra L; Gow, Andrew J

    2014-07-01

    Acute Cl2 exposure following industrial accidents or military/terrorist activity causes pulmonary injury and severe acute respiratory distress. Prior studies suggest that antioxidant depletion is important in producing dysfunction, however a pathophysiologic mechanism has not been elucidated. We propose that acute Cl2 inhalation leads to oxidative modification of lung lining fluid, producing surfactant inactivation, inflammation and mechanical respiratory dysfunction at the organ level. C57BL/6J mice underwent whole-body exposure to an effective 60ppm-hour Cl2 dose, and were euthanized 3, 24 and 48h later. Whereas pulmonary architecture and endothelial barrier function were preserved, transient neutrophilia, peaking at 24h, was noted. Increased expression of ARG1, CCL2, RETLNA, IL-1b, and PTGS2 genes was observed in bronchoalveolar lavage (BAL) cells with peak change in all genes at 24h. Cl2 exposure had no effect on NOS2 mRNA or iNOS protein expression, nor on BAL NO3(-) or NO2(-). Expression of the alternative macrophage activation markers, Relm-α and mannose receptor was increased in alveolar macrophages and pulmonary epithelium. Capillary surfactometry demonstrated impaired surfactant function, and altered BAL phospholipid and surfactant protein content following exposure. Organ level respiratory function was assessed by forced oscillation technique at 5 end expiratory pressures. Cl2 exposure had no significant effect on either airway or tissue resistance. Pulmonary elastance was elevated with time following exposure and demonstrated PEEP refractory derecruitment at 48h, despite waning inflammation. These data support a role for surfactant inactivation as a physiologic mechanism underlying respiratory dysfunction following Cl2 inhalation. PMID:24582687

  20. Acute Chlorine Gas Exposure Produces Transient Inflammation and a Progressive Alteration in Surfactant Composition with Accompanying Mechanical Dysfunction

    PubMed Central

    Massa, Christopher B; Scott, Pamela; Abramova, Elena; Gardner, Carol; Laskin, Debra L; Gow, Andrew J

    2014-01-01

    Acute Cl2 exposure following industrial accidents or military/terrorist activity causes pulmonary injury and severe acute respiratory distress. Prior studies suggest that antioxidant depletion is important in producing dysfunction, however a pathophysiologic mechanism has not been elucidated. We propose that acute Cl2 inhalation leads to oxidative modification of lung lining fluid, producing surfactant inactivation, inflammation and mechanical respiratory dysfunction at the organ level. C57BL/6J mice underwent whole-body exposure to an effective 60 ppm-hour Cl2 dose, and were sacrificed 3, 24 and 48 hours later. Whereas pulmonary architecture and endothelial barrier function were preserved, transient neutrophilia, peaking at 24 hours, was noted. Increased expression of ARG1, CCL2, RETLNA, IL-1b, and PTGS2 genes was observed in bronchoalveolar lavage (BAL) cells with peak change in all genes at 24 hours. Cl2 exposure had no effect on NOS2 mRNA or iNOS protein expression, nor on BAL NO3− or NO2−. Expression of the alternative macrophage activation markers, Relm-α and mannose receptor was increased in alveolar macrophages and pulmonary epithelium. Capillary surfactometry demonstrated impaired surfactant function, and altered BAL phospholipid and surfactant protein content following exposure. Organ level respiratory function was assessed by forced oscillation technique at 5 end expiratory pressures. Cl2 exposure had no significant effect on either airway or tissue resistance. Pulmonary elastance was elevated with time following exposure and demonstrated PEEP refractory derecruitment at 48 hours, despite waning inflammation. These data support a role for surfactant inactivation as a physiologic mechanism underlying respiratory dysfunction following Cl2 inhalation. PMID:24582687

  1. [What is the ideal attainment of clinical laboratory works?].

    PubMed

    Shibata, S

    1993-01-01

    This is the specified address delivered at the 20th meeting of the Chugoku-Shikoku District of the Japanese Society of Clinical Pathologists (JSCP). More than 40 years have elapsed since the incipient epoch of clinical pathology in this country, when physicians, surgeons and pathologists gathered, for the first time, to institute a scientific medical association (JSCP) for the purpose of elevating daily medical services to the modernized level through active use of clinical laboratory examination. Since then the laboratory examination has undergone a rapid progress and many new techniques have appeared. Excellent equipments and reagents are being supplied from the engineering and pharmaceutical companies. Thus, the clinical laboratories have assumed an out-look of a big factory equipped with a variety of automatic analysers and a large number of computers, and the figures of many laboratory staffs are peeped among them. In this situation there arose several problems urgently needed for control to hole the laboratory ideal in service to the medical doctors as well as to the patients. 1. Management of personnels (medical technologists and others) who are dissatisfied with daily robot-like works and discordant human relations. 2. Report sheets sent to the medical doctors are not employed adequately for the care of patients, because they are handed over in uncooked style without clinical laboratory interpretation and recommendation. Therefore, the laboratory medical doctors are ranked below the medical doctors on the wards and outpatient clinic. 3. Too many tests are ordered to the laboratory without adequate recognition of their usefulness.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8355410

  2. [Pathophysiologic and therapeutic aspects of the adult respiratory distress syndrome (ARDS)].

    PubMed

    Thiel, M; Forst, H; Peter, K

    1991-02-01

    Since the first characterization of the adult respiratory distress syndrome (ARDS), knowledge of its aetiology and pathogenesis has grown considerably. In spite of this, mortality remains up to 50 to 90%, particularly if multiple organ failure is present. Because no causative clinical therapy is available up to now, significant attention is given to preventive measures like early operative stabilisation of long bone fractures, or prophylaxis of nosocomial infections. After clinical manifestation of ARDS, treatment focuses on functional disturbances of the cardiopulmonary system and on the underlying disease. The aim of this symptomatic therapy is to ensure oxygen supply according to the organisms demand. It is still unknown, however, whether the mortality of patients with ARDS can be reduced by optimising the oxygen supply. In general, oxygen supply can be enhanced by improving pulmonary gas exchange, cardiac output and blood oxygen transport capacity. For practical use the therapy often ends up with a therapeutical dilemma: On one hand, the improvement of the pulmonary gas exchange by application of PEEP can be associated with a critical decline in cardiac output, particularly if the afterload of the right ventricle is elevated. On the other hand, to increase cardiac output, both volume replacement and vasodilators can severely affect pulmonary gas exchange if the alveolo-capillary permeability is increased and pulmonary hypoxic vasoconstriction is disturbed. Thus, oxygen supply can be optimised only via invasive monitoring of the cardiorespiratory system. Although still experimental, the most promising approaches seem to be pharmacological interventions directed at suppressing the formation and effects of various humoral and cellular mediators. An improved understanding of the inflammatory processes might provide new insights in the pathophysiology of ARDS and the related therapeutic interventions. PMID:1863681

  3. [High-frequency jet ventilation and the function of the right heart--an animal experimental study].

    PubMed

    Klein, U; Claussen, D; Gottschild, D; Langbein, T; Dahinten, H; Schubert, H; Granzow, N M

    1990-01-01

    In a controlled study, 10 dogs with normal and severely damaged lungs were subjected to nuclide angiocardiographic investigations into the function of the right ventricle. The pulmonary injury was produced by infusion of oleic acid (OA) into the right atrium during controlled ventilation (IPPV). The angiocardiographic examinations were performed using 133Xenon in the first pass technique. The study compared HFJV (HFJV 100, HFJV 300) with IPPV in the non-damaged lung as well as HFJV 300 with IPPV and CPPV (PEEP 1.0 kPa) after injury by OA. Whereas for the non-damaged lung no different right ventricular (RV) function between IPPV and HFJV was observed, the RV functional parameters after OA injury under HFJV showed, as opposed to CPPV, more favourable values on the whole. This became clear in particular in the significantly higher ejection fraction (RVEF) during HFJV. The RV function which is influenced during CPPV in terms of a favourable oxygenation is the consequence of an increased mean pressure in the airways with subsequent rise in the RV afterload and decrease in the RV preload. In contrast, the more favourable RV haemodynamics during HFJV are associated with a comparatively lower mean airway pressure and a significantly worse oxygenation. As the RV function also during HFJV has to be seen in direct dependence on the mean airway or intrapulmonary pressure necessary for sufficient oxygenation, the employment of this form of ventilation in the presence of an acute respiratory insufficiency has no impact on the RV haemodynamics different from the other compared forms of ventilation. PMID:2393481

  4. Defensive behaviors and prosencephalic neurogenesis in pigeons (Columba livia) are affected by environmental enrichment in adulthood.

    PubMed

    Melleu, F F; Pinheiro, M V; Lino-de-Oliveira, C; Marino-Neto, J

    2016-05-01

    Neurogenesis in the adult brain appears to be phylogenetically conserved across the animal kingdom. In pigeons and other adult non-oscine birds, immature neurons are observed in several prosencephalic areas, suggesting that neurogenesis may participate in the control of different behaviors. The mechanisms controlling neurogenesis and its relevance to defensive behaviors in non-oscine birds remain elusive. Herein, the contribution of the environment to behavior and neurogenesis of pigeons was investigated. Adult pigeons (Columba livia, n = 6/group), housed in standard (SE) or enriched environment (EE) for 42 days, were exposed to an unfamiliar environment (UE) followed by presentation to a novel object (NO). Video recordings of UE+NO tests were analyzed and scored for latency, duration and frequency of angular head movements, peeping, grooming, immobility and locomotion. Twenty-four hours later, pigeons were submitted to the tonic immobility test (TI) and number of trials for TI and TI duration were scored, followed by euthanasia 2 h later. Brains were immunohistochemically processed to reveal doublecortin (DCX), a marker for newborn neurons. Compared to those housed in SE, the pigeons housed in EE responded to a NO with more immobility. In addition, the pigeons housed in EE presented longer TI, more DCX-immunoreactive (DCX-ir) cells in the hippocampus and fewer DCX-ir cells in the lateral striatum than those housed in SE. There was no correlation between the number of DCX-ir cells and the scores of immobility in behavioral tests. Together, these data suggest that enrichment favored behavioral inhibition and neurogenesis in the adult pigeons through different, parallel mechanisms. PMID:25869276

  5. Ventilator-induced endothelial activation and inflammation in the lung and distal organs

    PubMed Central

    2009-01-01

    Introduction Results from clinical studies have provided evidence for the importance of leukocyte-endothelial interactions in the pathogenesis of pulmonary diseases such as acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), as well as in systemic events like sepsis and multiple organ failure (MOF). The present study was designed to investigate whether alveolar stretch due to mechanical ventilation (MV) may evoke endothelial activation and inflammation in healthy mice, not only in the lung but also in organs distal to the lung. Methods Healthy male C3H/HeN mice were anesthetized, tracheotomized and mechanically ventilated for either 1, 2 or 4 hours. To study the effects of alveolar stretch in vivo, we applied a MV strategy that causes overstretch of pulmonary tissue i.e. 20 cmH2O peak inspiratory pressure (PIP) and 0 cmH20 positive end expiratory pressure (PEEP). Non-ventilated, sham-operated animals served as a reference group (non-ventilated controls, NVC). Results Alveolar stretch imposed by MV did not only induce de novo synthesis of adhesion molecules in the lung but also in organs distal to the lung, like liver and kidney. No activation was observed in the brain. In addition, we demonstrated elevated cytokine and chemokine expression in pulmonary, hepatic and renal tissue after MV which was accompanied by enhanced recruitment of granulocytes to these organs. Conclusions Our data implicate that MV causes endothelial activation and inflammation in mice without pre-existing pulmonary injury, both in the lung and distal organs. PMID:19917112

  6. Perioperative lung protective ventilation in obese patients.

    PubMed

    Fernandez-Bustamante, Ana; Hashimoto, Soshi; Serpa Neto, Ary; Moine, Pierre; Vidal Melo, Marcos F; Repine, John E

    2015-01-01

    The perioperative use and relevance of protective ventilation in surgical patients is being increasingly recognized. Obesity poses particular challenges to adequate mechanical ventilation in addition to surgical constraints, primarily by restricted lung mechanics due to excessive adiposity, frequent respiratory comorbidities (i.e. sleep apnea, asthma), and concerns of postoperative respiratory depression and other pulmonary complications. The number of surgical patients with obesity is increasing, and facing these challenges is common in the operating rooms and critical care units worldwide. In this review we summarize the existing literature which supports the following recommendations for the perioperative ventilation in obese patients: (1) the use of protective ventilation with low tidal volumes (approximately 8 mL/kg, calculated based on predicted -not actual- body weight) to avoid volutrauma; (2) a focus on lung recruitment by utilizing PEEP (8-15 cmH2O) in addition to recruitment maneuvers during the intraoperative period, as well as incentivized deep breathing and noninvasive ventilation early in the postoperative period, to avoid atelectasis, hypoxemia and atelectrauma; and (3) a judicious oxygen use (ideally less than 0.8) to avoid hypoxemia but also possible reabsorption atelectasis. Obesity poses an additional challenge for achieving adequate protective ventilation during one-lung ventilation, but different lung isolation techniques have been adequately performed in obese patients by experienced providers. Postoperative efforts should be directed to avoid hypoventilation, atelectasis and hypoxemia. Further studies are needed to better define optimum protective ventilation strategies and analyze their impact on the perioperative outcomes of surgical patients with obesity. PMID:25907273

  7. Oxygen and anesthesia: what lung do we deliver to the post-operative ward?

    PubMed

    Hedenstierna, G

    2012-07-01

    Anesthesia is safe in most patients. However, anesthetics reduce functional residual capacity (FRC) and promote airway closure. Oxygen is breathed during the induction of anesthesia, and increased concentration of oxygen (O(2) ) is given during the surgery to reduce the risk of hypoxemia. However, oxygen is rapidly adsorbed behind closed airways, causing lung collapse (atelectasis) and shunt. Atelectasis may be a locus for infection and may cause pneumonia. Measures to prevent atelectasis and possibly reduce post-operative pulmonary complications are based on moderate use of oxygen and preservation or restoration of FRC. Pre-oxygenation with 100% O(2) causes atelectasis and should be followed by a recruitment maneuver (inflation to an airway pressure of 40 cm H(2) O for 10 s and to higher airway pressures in patients with reduced abdominal compliance (obese and patients with abdominal disorders). Pre-oxygenation with 80% O(2) may be sufficient in most patients with no anticipated difficulty in managing the airway, but time to hypoxemia during apnea decreases from mean 7 to 5 min. An alternative, possibly challenging, procedure is induction of anesthesia with continuous positive airway pressure/positive end-expiratory pressure to prevent fall in FRC enabling use of 100% O(2) . A continuous PEEP of 7-10 cm H(2) O may not necessarily improve oxygenation but should keep the lung open until the end of anesthesia. Inspired oxygen concentration of 30-40%, or even less, should suffice if the lung is kept open. The goal of the anesthetic regime should be to deliver a patient with no atelectasis to the post-operative ward and to keep the lung open. PMID:22471648

  8. Perioperative management of obese patients.

    PubMed

    Pelosi, Paolo; Gregoretti, Cesare

    2010-06-01

    Obesity is a metabolic disease that is on the increase all over the world. Up to 35% of the population in North America and 15-20% in Europe can be considered obese. Since these patients are characterised by several systemic physiopathological alterations, the perioperative management may present some problems, mainly related to their respiratory system. Body mass is an important determinant of respiratory function before and during anaesthesia not only in morbidly but also in moderately obese patients. These can manifest as (a) reduced lung volume with increased atelectasis; (b)derangements in respiratory system, lung and chest wall compliance and increased resistance; and (c) moderate to severe hypoxaemia. These physiological alterations are more marked in obese patients with hypercapnic syndrome or obstructive sleep apnoea syndrome. The suggested perioperative ventilation management includes (a) awake and/or facilitated endotracheal intubation by using a video-laryngoscope; (b) tidal volume of 6-10 ml kg(-1) ideal body weight, increasing respiratory rate to maintain physiological PaCO2, while avoiding intrinsic positive end-expiratory pressure (PEEPi); and (c) a recruitment manoeuvre (35-55 cmH2O for 6 s) followed by the application of an end-expiratory pressure (PEEP) of 10 cmH2O. The recruitment manoeuvre should always be performed only when a volemic and haemodynamic stabilisation is reached after induction of anaesthesia. In the postoperative period, beach chair position, aggressive physiotherapy, noninvasive respiratory support and short-term recovery in intermediate critical care units with care of fluid management and pain may be useful to reduce pulmonary complications. PMID:20608558

  9. The Effect of Omega-3 Fatty Acids on ARDS: A Randomized Double-Blind Study

    PubMed Central

    Parish, Masoud; Valiyi, Farnaz; Hamishehkar, Hadi; Sanaie, Sarvin; Asghari Jafarabadi, Mohammad; Golzari, Samad EJ; Mahmoodpoor, Ata

    2014-01-01

    Purpose: The aim of this study was to evaluate the effect of an enteral nutrition diet, enriched with omega-3 fatty acids because of its anti-inflammatory effects on treatment of patients with mild to moderate ARDS. Methods: This randomized clinical trial was performed in two ICUs of Tabriz University of Medical Sciences from Jun 2011 until Sep 2013 in north west of Iran. Fifty-eight patients with mild to moderate ARDS were enroled in this clinical trial. All patients received standard treatment for ARDS based on ARDS network trial. In intervention group, patients received 6 soft-gels of omega-3/day in addition to the standard treatment. Results: Tidal volume, PEEP, pH, PaO2/FiO2 , SaO2, P platue and PaCO2 on the 7th and 14th days didn’t have significant difference between two groups. Indices of lung mechanics (Resistance, Compliance) had significant difference between the groups on the 14th day. Pao2 had significant difference between two groups on both 7th and 14th days. Trend of PaO2 changes during the study period in two groups were significant. We showed that adjusted mortality rate did not have significant difference between two groups. Conclusion: It seems that adding omega-3 fatty acids to enteral diet of patients with ARDS has positive results in term of ventilator free days, oxygenation, lung mechanic indices; however, we need more multi center trials with large sample size and different doses of omega-3 fatty acids for their routine usage as an adjuant for ARDS treatment. PMID:25671189

  10. [Continuously alternating prone and supine positioning in acute lung failure].

    PubMed

    Walz, M; Muhr, G

    1992-11-01

    Acute respiratory failure is still one the main problems in surgical intensive care. Unknown pathophysiological mechanisms permit only symptomatic therapy. Today ventilatory strategies by using PEEP und IRV are established to improve gas exchange and FRC by recruiting collapsed alveoli, decreasing intrapulmonary shunting and returning V/Q matching to normal. Furthermore different studies have shown the effects of supine and lateral decubitus posture in patients with acute respiratory failure. There are only rare reports on using the prone position, which doesn't require two-lung ventilation in difference to lateral position. We have studied 16 patients with acute respiratory failure by using continuous changing between prone and supine position under mechanical ventilation. All were male, aged 41.3 years in the middle and showed an average "Injury Severity Score" of 30 (13-50). 15 were trauma patients with blunt chest trauma in 11 cases. We have used prone position on threatening or manifest ARDS. In all patients we observed an increment of PaO2 during prone position on to 48 mmHg so that FiO2 could be reduced on an average of 0.2 within the first 48 h since changing patient's position. Posture changing depends on blood gas analysis, specifically on decreasing PaO2 after previous increment. Patients remained in prone and supine position at a mean of 6.3 (4.5-20) h and posture changing was proceeded over a period of 15.4 (7-32) days. No problems recording to blood pressure or mechanical ventilation appeared during prone position. 11 of 16 patients survived (68.8%), 5 died of cardiac (2) and multi organic failure (3) in connection with sepsis.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1458988

  11. Early Hepatic Dysfunction Is Associated with a Worse Outcome in Patients Presenting with Acute Respiratory Distress Syndrome: A Post-Hoc Analysis of the ACURASYS and PROSEVA Studies

    PubMed Central

    Dizier, Stéphanie; Forel, Jean-Marie; Ayzac, Louis; Richard, Jean-Christophe; Hraiech, Sami; Lehingue, Samuel; Loundou, Anderson; Roch, Antoine; Guerin, Claude; Papazian, Laurent

    2015-01-01

    Introduction Bilirubin is well-recognized marker of hepatic dysfunction in intensive care unit (ICU) patients. Multiple organ failure often complicates acute respiratory distress syndrome (ARDS) evolution and is associated with high mortality. The effect of early hepatic dysfunction on ARDS mortality has been poorly investigated. We evaluated the incidence and the prognostic significance of increased serum bilirubin levels in the initial phase of ARDS. Methods The data of 805 patients with ARDS were retrospectively analysed. This population was extracted from two recent multicenter, prospective and randomised trials. Patients presenting with ARDS with a ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen < 150 mmHg measured with a PEEP ≥ 5 cm of water were included. The total serum bilirubin was measured at inclusion and at days 2, 4, 7 and 14. The primary objective was to analyse the bilirubin at inclusion according to the 90-day mortality rate. Results The 90-day mortality rate was 33.8% (n = 272). The non-survivors were older, had higher Sepsis-related Organ Failure Assessment (SOFA) score and were more likely to have a medical diagnosis on admission than the survivors. At inclusion, the SOFA score without the liver score (10.3±2.9 vs. 9.0±3.0, p<0.0001) and the serum bilirubin levels (36.1±57.0 vs. 20.5±31.5 μmol/L, p<0.0001) were significantly higher in the non-survivors than in the survivors. Age, the hepatic SOFA score, the coagulation SOFA score, the arterial pH level, and the plateau pressure were independently associated with 90-day mortality in patients with ARDS. Conclusion Bilirubin used as a surrogate marker of hepatic dysfunction and measured early in the course of ARDS was associated with the 90-day mortality rate. PMID:26636318

  12. AARC Clinical Practice Guidelines. Endotracheal suctioning of mechanically ventilated patients with artificial airways 2010.

    PubMed

    2010-06-01

    An electronic literature search for articles published between January 1990 and October 2009 was conducted by using MEDLINE, CINAHL, and Cochrane Library databases. The update of this clinical practice guideline is the result of reviewing a total of 114 clinical trials, 62 reviews and 6 meta-analyses on endotracheal suctioning. The following recommendations are made following the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria: (1) It is recommended that endotracheal suctioning should be performed only when secretions are present, and not routinely; (2) It is suggested that pre-oxygenation be considered if the patient has a clinically important reduction in oxygen saturation with suctioning; (3) Performing suctioning without disconnecting the patient from the ventilator is suggested; (4) Use of shallow suction is suggested instead of deep suction, based on evidence from infant and pediatric studies; (5) It is suggested that routine use of normal saline instillation prior to endotracheal suction should not be performed; (6) The use of closed suction is suggested for adults with high F(I)O2, or PEEP, or at risk for lung de-recruitment, and for neonates; (7) Endotracheal suctioning without disconnection (closed system) is suggested in neonates; (8) Avoidance of disconnection and use of lung recruitment maneuvers are suggested if suctioning-induced lung de-recruitment occurs in patients with ; (9) It is suggested that a suction catheter is used that occludes less than 50% the lumen of the endotracheal tube in children and adults, and less than 70% in infants; (10) It is suggested that the duration of the suctioning event be limited to less than 15 seconds. PMID:20507660

  13. The analysis of components that lead to increased work of breathing in chronic obstructive pulmonary disease patients

    PubMed Central

    Chen, Sibei; Li, Ying; Zheng, Zeguang; Luo, Qun

    2016-01-01

    Background This study is to explore the components and related mechanism responsible for the increase of work of breathing (WB) in chronic obstructive pulmonary disease (COPD) patients. Methods Eight COPD patients and eight healthy volunteers were recruited in the study. The rebreathing method was used to increase end-tidal CO2 partial pressure (PetCO2) and stimulate the increase in ventilation (VE). The increase in VE, WB, and changes in the compositions of WB were observed and analyzed. The WB and its components were calculated using the Campbell diagram. Results The inspiratory work (Wi) of breathing, a major component of total work of breathing (Wtot), in the COPD group was significantly higher than the control group during quiet breathing (P<0.05). As the minute VE increased, Wtot and Wi increased in a linear manner, and the slope of increase was significantly higher in the COPD group as compared to the normal group (P<0.05). The analyses of changes in overcoming airway resistance (Wrs) and lung/chest-wall elastance (Wel) indicated that the slope of increase (response to VE increase) of Wrs was not significantly different between the two groups (P>0.05) although the Wrs in the COPD group was always higher than the normal group (P<0.05). However, as the VE increased, the slope of the increase in Wel was significantly higher in the COPD group than the normal group. Work done to overcome the intrinsic PEEP (WPEEPi), a component of the Wel, was not observed in the control group. However, WPEEPi increased gradually as VE increased and accounted for 56% of Wel at the end of rebreathing trial in COPD group. Conclusions Airway resistance was the main cause for increased WB during quiet breathing. As the VE increased, an increase of WPEEPi became an important part of increased WB in COPD patients, so it is important to reduce dynamic hyperinflation in COPD patients. PMID:27621878

  14. Biphasic positive airway pressure minimizes biological impact on lung tissue in mild acute lung injury independent of etiology

    PubMed Central

    2013-01-01

    Introduction Biphasic positive airway pressure (BIVENT) is a partial support mode that employs pressure-controlled, time-cycled ventilation set at two levels of continuous positive airway pressure with unrestricted spontaneous breathing. BIVENT can modulate inspiratory effort by modifying the frequency of controlled breaths. Nevertheless, the optimal amount of inspiratory effort to improve respiratory function while minimizing ventilator-associated lung injury during partial ventilatory assistance has not been determined. Furthermore, it is unclear whether the effects of partial ventilatory support depend on acute lung injury (ALI) etiology. This study aimed to investigate the impact of spontaneous and time-cycled control breaths during BIVENT on the lung and diaphragm in experimental pulmonary (p) and extrapulmonary (exp) ALI. Methods This was a prospective, randomized, controlled experimental study of 60 adult male Wistar rats. Mild ALI was induced by Escherichia coli lipopolysaccharide either intratracheally (ALIp) or intraperitoneally (ALIexp). After 24 hours, animals were anesthetized and further randomized as follows: (1) pressure-controlled ventilation (PCV) with tidal volume (Vt) = 6 ml/kg, respiratory rate = 100 breaths/min, PEEP = 5 cmH2O, and inspiratory-to-expiratory ratio (I:E) = 1:2; or (2) BIVENT with three spontaneous and time-cycled control breath modes (100, 75, and 50 breaths/min). BIVENT was set with two levels of CPAP (Phigh = 10 cmH2O and Plow = 5 cmH2O). Inspiratory time was kept constant (Thigh = 0.3 s). Results BIVENT was associated with reduced markers of inflammation, apoptosis, fibrogenesis, and epithelial and endothelial cell damage in lung tissue in both ALI models when compared to PCV. The inspiratory effort during spontaneous breaths increased during BIVENT-50 in both ALI models. In ALIp, alveolar collapse was higher in BIVENT-100 than PCV, but decreased during BIVENT-50, and diaphragmatic injury was lower during BIVENT-50 compared

  15. [The application of n-acetylcysteine as an antioxidant and mucolytic in mechanical ventilation in intensive care patients. A prospective, randomized, placebo-controlled, double-blind study].

    PubMed

    Konrad, F; Schoenberg, M H; Wiedmann, H; Kilian, J; Georgieff, M

    1995-09-01

    the BAL (Figs. 1, 2). Plasma concentrations of malondialdehyde were similar (Fig. 3). Only the levels of conjugated dienes were significantly higher on the 5th treatment day in the placebo group (Fig. 4). The organ function of the lung (FiO2, PEEP, PaO2), liver (SGOT, bilirubin), and kidney (creatinine) and coagulation parameters (PTT, prothrombin time, platelet count) were similar in the two groups during the time of investigation. We observed no clinically relevant differences in the tracheobronchial mucus (Table 2). CONCLUSION. The present data do not support routine use of NAC in ventilated patients, either as an antioxidant or as a mucolytic agent. Intravenous administration of 3 g NAC/day had no clinically relevant effect on glutathione levels, lipid peroxidation products, tracheobronchial mucus, and clinical condition. PMID:7485927

  16. THE ASSOCIATION BETWEEN PHYSIOLOGIC DEAD-SPACE FRACTION AND MORTALITY IN PATIENTS WITH THE ACUTE RESPIRATORY DISTRESS SYNDROME ENROLLED INTO A PROSPECTIVE MULTI-CENTERED CLINICAL TRIAL

    PubMed Central

    Kallet, Richard H; Zhuo, Hanjing; Liu, Kathleen D.; Calfee, Carolyn S.; Matthay, Michael A

    2014-01-01

    Objective To test the association between pulmonary dead-space fraction (VD/VT) and mortality in patients with ARDS (Berlin Definition, PaO2/FiO2 ≤ 300 mm Hg; PEEP ≥ 5 cm H2O) enrolled into a clinical trial incorporating lung-protective ventilation. Design Prospective, multi-center study. Setting Medical-surgical intensive care units in the United States. Subjects 126 ALI patients enrolled into a phase III randomized, placebo-controlled study of aerosolized albuterol. Interventions None Measurements and Main Results VD/VT and pulmonary mechanics were measured within 4 hours of enrollment and repeated daily on study days 1 and 2 in subjects requiring arterial blood gases for clinical management. At baseline, non-survivors had a trend towards higher VD/VT compared to survivors (0.62 ± 0.11 vs. 0.56 ± 0.11 respectively, p = 0.08). Differences in VD/VT between non-survivors and survivors became significant on study days 1 (0.64 ± 0.12 vs. 0.55 ± 0.11 respectively, p = 0.01) and 2 (0.67 ± 0.12 vs. 0.56 ± 0.11 respectively, p=0.004). Likewise, the association between VD/VT and mortality was significant on study day 1 (odds ratio per 0.10 change in VD/VT [95% confidence interval]: 6.84 [1.62–28.84] p = 0.01; and study day 2: 4.90 [1.28–18.73] p = 0.02) after adjusting for VD/VT, PaO2/FiO2, oxygenation index, vasopressor use and the primary risk for ARDS. Using a Cox proportional hazard model, VD/VT was associated with a trend towards higher mortality (HR = 4.37 [CI: 0.99 – 19.32]; p = 0.052) that became significant when the analysis was adjusted for daily oxygenation index (HR = 1.74 [95% CI: 1.12 – 3.35] p = 0.04). Conclusions Markedly elevated VD/VT (≥ 0.60) in early ARDS is associated with higher mortality. Measuring VD/VT may be useful in identifying ARDS patients at increased risk of death who are enrolled into a therapeutic trial. PMID:24381187

  17. Effects of methacholine infusion on desflurane pharmacokinetics in piglets.

    PubMed

    Kozian, Alf; Kretzschmar, Moritz; Baumgardner, James E; Schreiber, Jens; Hedenstierna, Göran; Larsson, Anders; Hachenberg, Thomas; Schilling, Thomas

    2015-12-01

    The data of a corresponding animal experiment demonstrates that nebulized methacholine (MCh) induced severe bronchoconstriction and significant inhomogeneous ventilation and pulmonary perfusion (V̇A/Q̇) distribution in pigs, which is similar to findings in human asthma. The inhalation of MCh induced bronchoconstriction and delayed both uptake and elimination of desflurane (Kretzschmar et al., 2015) [1]. The objective of the present data is to determine V̇A/Q̇ matching by Multiple Inert Gas Elimination Technique (MIGET) in piglets before and during methacholine- (MCh-) induced bronchoconstriction, induced by MCh infusion, and to assess the blood concentration profiles for desflurane (DES) by Micropore Membrane Inlet Mass Spectrometry (MMIMS). Healthy piglets (n=4) under general anesthesia were instrumented with arterial, central venous, and pulmonary artery lines. The airway was secured via median tracheostomy with an endotracheal tube, and animals were mechanically ventilated with intermittent positive pressure ventilation (IPPV) with a FiO2 of 0.4, tidal volume (V T)=10 ml/kg and PEEP of 5cmH2O using an open system. The determination of V.A/Q. was done by MIGET: before desflurane application and at plateau in both healthy state and during MCh infusion. Arterial blood was sampled at 0, 1, 2, 5, 10, 20, and 30 min during wash-in and washout, respectively. Bronchoconstriction was established by MCH infusion aiming at doubling the peak airway pressure, after which wash-in and washout of the anesthetic gas was repeated. Anesthesia gas concentrations were measured by MMIMS. Data were analyzed by ANOVA, paired t-test, and by nonparametric Friedman׳s test and Wilcoxon׳s matched pairs test. We measured airway pressures, pulmonary resistance, and mean paO2 as well as hemodynamic variables in all pigs before desflurane application and at plateau in both healthy state and during methacholine administration by infusion. By MIGET, fractional alveolar ventilation and

  18. Nasal high–flow oxygen therapy in patients with hypoxic respiratory failure: effect on functional and subjective respiratory parameters compared to conventional oxygen therapy and non-invasive ventilation (NIV)

    PubMed Central

    2014-01-01

    Background Aim of the study was to compare the short-term effects of oxygen therapy via a high-flow nasal cannula (HFNC) on functional and subjective respiratory parameters in patients with acute hypoxic respiratory failure in comparison to non-invasive ventilation (NIV) and standard treatment via a Venturi mask. Methods Fourteen patients with acute hypoxic respiratory failure were treated with HFNC (FiO2 0.6, gas flow 55 l/min), NIV (FiO2 0.6, PEEP 5 cm H2O Hg, tidal volume 6–8 ml/kg ideal body weight,) and Venturi mask (FiO2 0.6, oxygen flow 15 l/min,) in a randomized order for 30 min each. Data collection included objective respiratory and circulatory parameters as well as a subjective rating of dyspnea and discomfort by the patients on a 10-point scale. In a final interview, all three methods were comparatively evaluated by each patient using a scale from 1 (=very good) to 6 (=failed) and the patients were asked to choose one method for further treatment. Results PaO2 was highest under NIV (129 ± 38 mmHg) compared to HFNC (101 ± 34 mmHg, p <0.01 vs. NIV) and VM (85 ± 21 mmHg, p <0.001 vs. NIV, p <0.01 vs. HFNC, ANOVA). All other functional parameters showed no relevant differences. In contrast, dyspnea was significantly better using a HFNC (2.9 ± 2.1, 10-point Borg scale) compared to NIV (5.0 ± 3.3, p <0.05), whereas dyspnea rating under HFNC and VM (3.3 ± 2.3) was not significantly different. A similar pattern was found when patients rated their overall discomfort on the 10 point scale: HFNC 2.7 ± 1.8, VM 3.1 ± 2.8 (ns vs. HFNC), NIV 5.4 ± 3.1 (p <0.05 vs. HFNC). In the final evaluation patients gave the best ratings to HFNC 2.3 ± 1.4, followed by VM 3.2 ± 1.7 (ns vs. HFNC) and NIV 4.5 ± 1.7 (p <0.01 vs. HFNC and p <0.05 vs. VM). For further treatment 10 patients chose HFNC, three VM and one NIV. Conclusions In hypoxic respiratory failure HFNC offers a good balance between oxygenation and comfort compared to NIV and Venturi mask and seems to be

  19. A decision support system to determine optimal ventilator settings

    PubMed Central

    2014-01-01

    Background Choosing the correct ventilator settings for the treatment of patients with respiratory tract disease is quite an important issue. Since the task of specifying the parameters of ventilation equipment is entirely carried out by a physician, physician’s knowledge and experience in the selection of these settings has a direct effect on the accuracy of his/her decisions. Nowadays, decision support systems have been used for these kinds of operations to eliminate errors. Our goal is to minimize errors in ventilation therapy and prevent deaths caused by incorrect configuration of ventilation devices. The proposed system is designed to assist less experienced physicians working in the facilities without having lung mechanics like cottage hospitals. Methods This article describes a decision support system proposing the ventilator settings required to be applied in the treatment according to the patients’ physiological information. The proposed model has been designed to minimize the possibility of making a mistake and to encourage more efficient use of time in support of the decision making process while the physicians make critical decisions about the patient. Artificial Neural Network (ANN) is implemented in order to calculate frequency, tidal volume, FiO2 outputs, and this classification model has been used for estimation of pressure support / volume support outputs. For the obtainment of the highest performance in both models, different configurations have been tried. Various tests have been realized for training methods, and a number of hidden layers mostly affect factors regarding the performance of ANNs. Results The physiological information of 158 respiratory patients over the age of 60 and were treated in three different hospitals between the years 2010 and 2012 has been used in the training and testing of the system. The diagnosed disease, core body temperature, pulse, arterial systolic pressure, diastolic blood pressure, PEEP, PSO2, pH, pCO2

  20. Effects of pressure-controlled and volume-controlled ventilation on respiratory mechanics and systemic stress response during laparoscopic cholecystectomy.

    PubMed

    Sen, Oznur; Umutoglu, Tarik; Aydın, Nurdan; Toptas, Mehmet; Tutuncu, Ayse Cigdem; Bakan, Mefkur

    2016-01-01

    Pressure-controlled ventilation (PCV) is less frequently employed in general anesthesia. With its high and decelerating inspiratory flow, PCV has faster tidal volume delivery and different gas distribution. The same tidal volume setting, delivered by PCV versus volume-controlled ventilation (VCV), will result in a lower peak airway pressure and reduced risk of barotrauma. We hypothesized that PCV instead of VCV during laparoscopic surgery could achieve lower airway pressures and reduce the systemic stress response. Forty ASA I-II patients were randomly selected to receive either the PCV (Group PC, n = 20) or VCV (Group VC, n = 20) during laparoscopic cholecystectomy. Blood sampling was made for baseline arterial blood gases (ABG), cortisol, insulin, and glucose levels. General anesthesia with sevoflurane and fentanyl was employed to all patients. After anesthesia induction and endotracheal intubation, patients in Group PC were given pressure support to form 8 mL/kg tidal volume and patients in Group VC was maintained at 8 mL/kg tidal volume calculated using predicted body weight. All patients were maintained with 5 cmH2O positive-end expiratory pressure (PEEP). Respiratory parameters were recorded before and 30 min after pneumoperitonium. Assessment of ABG and sampling for cortisol, insulin and glucose levels were repeated 30 min after pneumoperitonium and 60 min after extubation. The P-peak levels observed before (18.9 ± 3.8 versus 15 ± 2.2 cmH2O) and during (23.3 ± 3.8 versus 20.1 ± 2.9 cmH2O) pneumoperitoneum in Group VC were significantly higher. Postoperative partial arterial oxygen pressure (PaO2) values are higher (98 ± 12 versus 86 ± 11 mmHg) in Group PC. Arterial carbon dioxide pressure (PaCO2) values (41.8 ± 5.4 versus 36.7 ± 3.5 mmHg) during pneumoperitonium and post-operative mean cortisol and insulin levels were higher in Group VC. When compared to VCV mode, PCV mode may improve compliance during pneumoperitoneum

  1. Hypervolemia induces and potentiates lung damage after recruitment maneuver in a model of sepsis-induced acute lung injury

    PubMed Central

    2010-01-01

    Introduction Recruitment maneuvers (RMs) seem to be more effective in extrapulmonary acute lung injury (ALI), caused mainly by sepsis, than in pulmonary ALI. Nevertheless, the maintenance of adequate volemic status is particularly challenging in sepsis. Since the interaction between volemic status and RMs is not well established, we investigated the effects of RMs on lung and distal organs in the presence of hypovolemia, normovolemia, and hypervolemia in a model of extrapulmonary lung injury induced by sepsis. Methods ALI was induced by cecal ligation and puncture surgery in 66 Wistar rats. After 48 h, animals were anesthetized, mechanically ventilated and randomly assigned to 3 volemic status (n = 22/group): 1) hypovolemia induced by blood drainage at mean arterial pressure (MAP)≈70 mmHg; 2) normovolemia (MAP≈100 mmHg), and 3) hypervolemia with colloid administration to achieve a MAP≈130 mmHg. In each group, animals were further randomized to be recruited (CPAP = 40 cm H2O for 40 s) or not (NR) (n = 11/group), followed by 1 h of protective mechanical ventilation. Echocardiography, arterial blood gases, static lung elastance (Est,L), histology (light and electron microscopy), lung wet-to-dry (W/D) ratio, interleukin (IL)-6, IL-1β, caspase-3, type III procollagen (PCIII), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) mRNA expressions in lung tissue, as well as lung and distal organ epithelial cell apoptosis were analyzed. Results We observed that: 1) hypervolemia increased lung W/D ratio with impairment of oxygenation and Est,L, and was associated with alveolar and endothelial cell damage and increased IL-6, VCAM-1, and ICAM-1 mRNA expressions; and 2) RM reduced alveolar collapse independent of volemic status. In hypervolemic animals, RM improved oxygenation above the levels observed with the use of positive-end expiratory pressure (PEEP), but increased lung injury and led to higher inflammatory and fibrogenetic

  2. Effects of methacholine infusion on desflurane pharmacokinetics in piglets☆

    PubMed Central

    Kozian, Alf; Kretzschmar, Moritz; Baumgardner, James E.; Schreiber, Jens; Hedenstierna, Göran; Larsson, Anders; Hachenberg, Thomas; Schilling, Thomas

    2015-01-01

    The data of a corresponding animal experiment demonstrates that nebulized methacholine (MCh) induced severe bronchoconstriction and significant inhomogeneous ventilation and pulmonary perfusion (V̇A/Q̇) distribution in pigs, which is similar to findings in human asthma. The inhalation of MCh induced bronchoconstriction and delayed both uptake and elimination of desflurane (Kretzschmar et al., 2015) [1]. The objective of the present data is to determine V̇A/Q̇ matching by Multiple Inert Gas Elimination Technique (MIGET) in piglets before and during methacholine- (MCh-) induced bronchoconstriction, induced by MCh infusion, and to assess the blood concentration profiles for desflurane (DES) by Micropore Membrane Inlet Mass Spectrometry (MMIMS). Healthy piglets (n=4) under general anesthesia were instrumented with arterial, central venous, and pulmonary artery lines. The airway was secured via median tracheostomy with an endotracheal tube, and animals were mechanically ventilated with intermittent positive pressure ventilation (IPPV) with a FiO2 of 0.4, tidal volume (VT)=10 ml/kg and PEEP of 5cmH2O using an open system. The determination of V.A/Q. was done by MIGET: before desflurane application and at plateau in both healthy state and during MCh infusion. Arterial blood was sampled at 0, 1, 2, 5, 10, 20, and 30 min during wash-in and washout, respectively. Bronchoconstriction was established by MCH infusion aiming at doubling the peak airway pressure, after which wash-in and washout of the anesthetic gas was repeated. Anesthesia gas concentrations were measured by MMIMS. Data were analyzed by ANOVA, paired t-test, and by nonparametric Friedman׳s test and Wilcoxon׳s matched pairs test. We measured airway pressures, pulmonary resistance, and mean paO2 as well as hemodynamic variables in all pigs before desflurane application and at plateau in both healthy state and during methacholine administration by infusion. By MIGET, fractional alveolar ventilation and

  3. Comparison between Variable and Conventional Volume-Controlled Ventilation on Cardiorespiratory Parameters in Experimental Emphysema

    PubMed Central

    Henriques, Isabela; Padilha, Gisele A.; Huhle, Robert; Wierzchon, Caio; Miranda, Paulo J. B.; Ramos, Isalira P.; Rocha, Nazareth; Cruz, Fernanda F.; Santos, Raquel S.; de Oliveira, Milena V.; Souza, Sergio A.; Goldenberg, Regina C.; Luiz, Ronir R.; Pelosi, Paolo; de Abreu, Marcelo G.; Silva, Pedro L.; Rocco, Patricia R. M.

    2016-01-01

    Emphysema is characterized by loss of lung tissue elasticity and destruction of structures supporting alveoli and capillaries. The impact of mechanical ventilation strategies on ventilator-induced lung injury (VILI) in emphysema is poorly defined. New ventilator strategies should be developed to minimize VILI in emphysema. The present study was divided into two protocols: (1) characterization of an elastase-induced emphysema model in rats and identification of the time point of greatest cardiorespiratory impairment, defined as a high specific lung elastance associated with large right ventricular end-diastolic area; and (2) comparison between variable (VV) and conventional volume-controlled ventilation (VCV) on lung mechanics and morphometry, biological markers, and cardiac function at that time point. In the first protocol, Wistar rats (n = 62) received saline (SAL) or porcine pancreatic elastase (ELA) intratracheally once weekly for 4 weeks, respectively. Evaluations were performed 1, 3, 5, or 8 weeks after the last intratracheal instillation of saline or elastase. After identifying the time point of greatest cardiorespiratory impairment, an additional 32 Wistar rats were randomized into the SAL and ELA groups and then ventilated with VV or VCV (n = 8/group) [tidal volume (VT) = 6 mL/kg, positive end-expiratory pressure (PEEP) = 3 cmH2O, fraction of inspired oxygen (FiO2) = 0.4] for 2 h. VV was applied on a breath-to-breath basis as a sequence of randomly generated VT values (mean VT = 6 mL/kg), with a 30% coefficient of variation. Non-ventilated (NV) SAL and ELA animals were used for molecular biology analysis. The time point of greatest cardiorespiratory impairment, was observed 5 weeks after the last elastase instillation. At this time point, interleukin (IL)-6, cytokine-induced neutrophil chemoattractant (CINC)-1, amphiregulin, angiopoietin (Ang)-2, and vascular endothelial growth factor (VEGF) mRNA levels were higher in ELA compared to SAL. In ELA animals

  4. Methods of in-vivo mouse lung micro-CT

    NASA Astrophysics Data System (ADS)

    Recheis, Wolfgang A.; Nixon, Earl; Thiesse, Jacqueline; McLennan, Geoffrey; Ross, Alan; Hoffman, Eric

    2005-04-01

    Micro-CT will have a profound influence on the accumulation of anatomical and physiological phenotypic changes in natural and transgenetic mouse models. Longitudinal studies will be greatly facilitated, allowing for a more complete and accurate description of events if in-vivo studies are accomplished. The purpose of the ongoing project is to establish a feasible and reproducible setup for in-vivo mouse lung micro-computed tomography (μCT). We seek to use in-vivo respiratory-gated μCT to follow mouse models of lung disease with subsequent recovery of the mouse. Methodologies for optimizing scanning parameters and gating for the in-vivo mouse lung are presented. A Scireq flexiVent ventilated the gas-anesthetized mice at 60 breaths/minute, 30 cm H20 PEEP, 30 ml/kg tidal volume and provided a respiratory signal to gate a Skyscan 1076 μCT. Physiologic monitoring allowed the control of vital functions and quality of anesthesia, e.g. via ECG monitoring. In contrary to longer exposure times with ex-vivo scans, scan times for in-vivo were reduced using 35μm pixel size, 158ms exposure time and 18μm pixel size, 316ms exposure time to reduce motion artifacts. Gating via spontaneous breathing was also tested. Optimal contrast resolution was achieved at 50kVp, 200μA, applying an aluminum filter (0.5mm). There were minimal non-cardiac related motion artifacts. Both 35μm and 1μm voxel size images were suitable for evaluation of the airway lumen and parenchymal density. Total scan times were 30 and 65 minutes respectively. The mice recovered following scanning protocols. In-vivo lung scanning with recovery of the mouse delivered reasonable image quality for longitudinal studies, e.g. mouse asthma models. After examining 10 mice, we conclude μCT is a feasible tool evaluating mouse models of lung pathology in longitudinal studies with increasing anatomic detail available for evaluation as one moves from in-vivo to ex-vivo studies. Further developments include automated

  5. Pleural effusion in ARDS.

    PubMed

    Formenti, P; Umbrello, M

    2014-02-01

    Pleural effusion is a fluid collection within the pleural space and is a common finding in mechanically ventilated patients. It is frequently related to fluid overload, hyponcotic states, heart failure, and altered pleural pressure due to atelectasis or pneumonia. Recent literature has shown that its incidence within ARDS is increasing, even if, in most of cases, at least in the early phases, it seems of limited clinical relevance. Most of the knowledge of Pleural Effusion and of its interaction with lung/chest wall mechanics derives from a small number of experimental studies and from some clinical studies, in most of the cases performed with normal lung parenchyma. In ARDS, however, Pleural Effusion seems to have a little effect "per se" on tidal mechanics and oxygenation (increasing elastance and reducing PO2), that are already profoundly affected by the lung injury itself. To sum up all the observations, we can assume that Pleural Effusion alters regional transmural pressure, restricting more the inspiration phase, and creating an opening/closure effect that can be reverted by PEEP application in recruitable lungs. This restores volume and compliance only if the abdomen is normally expansible. Drainage of Pleural Effusion is frequently performed in ICU but the benefits and risks are not well established. Lung ultrasound is an effective technique with high sensitivity and specificity for both bedside diagnosis and drainage guidance. It may help to quantify and qualify the effusion and at the same time the grade of aeration of underling parenchyma. Aim of this review is to summarize the current evidence and opinions about the interaction between Pleural Effusion and positive pressure ventilation in the presence of ARDS, its impact on gas exchange and tidal mechanics, trying to figure out the best bedside management that is not available yet. The estimation of both lung and chest wall elastance may help in the clinical decision making whether to drain or not in

  6. Protein profiling of Haemonchus contortus found in sheep of Kashmir valley.

    PubMed

    Tak, Irfan-Ur-Rauf; Chishti, M Z; Ahmad, Fayaz

    2015-12-01

    Economic losses due to helminth parasites in sheep throughout the world are considerable. Haemonchus contortus is a blood sucking intestinal helminth that lives in the abomasum of small ruminants worldwide. This parasite can be devastating to producers as it causes decreased production levels due to clinical signs such as anaemia, edema and death. For isolation of the proteins of the parasite, a well defined methodology was adopted. The abomasae of sheep in which this parasite resides were collected from abattoirs of various districts and were then carried to laboratory for screening. In case of collection sites falling in far areas, the organs were screened on spot. The parasites were collected in normal saline, washed and stored in 0.05 M PBS with pH of 7.4 at 0 °C. After refrigeration, frozen nematodes were thawed, homogenized and centrifuged at 1,000-15,000 rpm for 15 min. The supernatant was thus collected as a protein mixture and stored at -20 °C. Protein concentration of the samples was estimated by Lowry method. The samples were then analyzed through PAGE and then through SDS-PAGE. Protein estimation of the samples was estimated to be 4.2 mg/ml. The processed parasite samples were then subjected to PAGE and SDS-PAGE to determine the presence of the proteins. It showed high concentration of proteins in its whole protein profile. The proteins were seen as continuous bands intermixing with each other in PAGE analysis. The present study revealed two bands of molecular weights-55 and 33 kDa in PAGE analysis. The proteins when analyzed through SDS-PAGE were mostly found in the range of 25-70 kDa. The SDS-PAGE analysis showed four prominent bands. These bands were of the molecular weights of 66, 40, 33 and 26 kDa. The present work was a challenging one since only a single study was conducted in this region on this aspect and thus obviously was a big task to peep into the field where scanty input was available. PMID:26688626

  7. Comparison between Variable and Conventional Volume-Controlled Ventilation on Cardiorespiratory Parameters in Experimental Emphysema.

    PubMed

    Henriques, Isabela; Padilha, Gisele A; Huhle, Robert; Wierzchon, Caio; Miranda, Paulo J B; Ramos, Isalira P; Rocha, Nazareth; Cruz, Fernanda F; Santos, Raquel S; de Oliveira, Milena V; Souza, Sergio A; Goldenberg, Regina C; Luiz, Ronir R; Pelosi, Paolo; de Abreu, Marcelo G; Silva, Pedro L; Rocco, Patricia R M

    2016-01-01

    Emphysema is characterized by loss of lung tissue elasticity and destruction of structures supporting alveoli and capillaries. The impact of mechanical ventilation strategies on ventilator-induced lung injury (VILI) in emphysema is poorly defined. New ventilator strategies should be developed to minimize VILI in emphysema. The present study was divided into two protocols: (1) characterization of an elastase-induced emphysema model in rats and identification of the time point of greatest cardiorespiratory impairment, defined as a high specific lung elastance associated with large right ventricular end-diastolic area; and (2) comparison between variable (VV) and conventional volume-controlled ventilation (VCV) on lung mechanics and morphometry, biological markers, and cardiac function at that time point. In the first protocol, Wistar rats (n = 62) received saline (SAL) or porcine pancreatic elastase (ELA) intratracheally once weekly for 4 weeks, respectively. Evaluations were performed 1, 3, 5, or 8 weeks after the last intratracheal instillation of saline or elastase. After identifying the time point of greatest cardiorespiratory impairment, an additional 32 Wistar rats were randomized into the SAL and ELA groups and then ventilated with VV or VCV (n = 8/group) [tidal volume (VT) = 6 mL/kg, positive end-expiratory pressure (PEEP) = 3 cmH2O, fraction of inspired oxygen (FiO2) = 0.4] for 2 h. VV was applied on a breath-to-breath basis as a sequence of randomly generated VT values (mean VT = 6 mL/kg), with a 30% coefficient of variation. Non-ventilated (NV) SAL and ELA animals were used for molecular biology analysis. The time point of greatest cardiorespiratory impairment, was observed 5 weeks after the last elastase instillation. At this time point, interleukin (IL)-6, cytokine-induced neutrophil chemoattractant (CINC)-1, amphiregulin, angiopoietin (Ang)-2, and vascular endothelial growth factor (VEGF) mRNA levels were higher in ELA compared to SAL. In ELA animals

  8. Lung Function and Organ Dysfunctions in 178 Patients Requiring Mechanical Ventilation During The 2009 Influenza A (H1N1) Pandemic

    PubMed Central

    2011-01-01

    Introduction Most cases of the 2009 influenza A (H1N1) infection are self-limited, but occasionally the disease evolves to a severe condition needing hospitalization. Here we describe the evolution of the respiratory compromise, ventilatory management and laboratory variables of patients with diffuse viral pneumonitis caused by pandemic 2009 influenza A (H1N1) admitted to the ICU. Method This was a multicenter, prospective inception cohort study including adult patients with acute respiratory failure requiring mechanical ventilation (MV) admitted to 20 ICUs in Argentina between June and September of 2009 during the influenza A (H1N1) pandemic. In a standard case-report form, we collected epidemiological characteristics, results of real-time reverse-transcriptase--polymerase-chain-reaction viral diagnostic tests, oxygenation variables, acid-base status, respiratory mechanics, ventilation management and laboratory tests. Variables were recorded on ICU admission and at days 3, 7 and 10. Results During the study period 178 patients with diffuse viral pneumonitis requiring MV were admitted. They were 44 ± 15 years of age, with Acute Physiology And Chronic Health Evaluation II (APACHE II) scores of 18 ± 7, and most frequent comorbidities were obesity (26%), previous respiratory disease (24%) and immunosuppression (16%). Non-invasive ventilation (NIV) was applied in 49 (28%) patients on admission, but 94% were later intubated. Acute respiratory distress syndrome (ARDS) was present throughout the entire ICU stay in the whole group (mean PaO2/FIO2 170 ± 25). Tidal-volumes used were 7.8 to 8.1 ml/kg (ideal body weight), plateau pressures always remained < 30 cmH2O, without differences between survivors and non-survivors; and mean positive end-expiratory pressure (PEEP) levels used were between 8 to 12 cm H2O. Rescue therapies, like recruitment maneuvers (8 to 35%), prone positioning (12 to 24%) and tracheal gas insufflation (3%) were frequently applied. At all time points

  9. [State of the art - intensive care therapy of septic patients].

    PubMed

    Reith, Sebastian; Ortlepp, Jan Rudolf

    2016-07-01

    After recognition of the diagnosis sepsis early resuscitation of the patient is mandatory. Patients should have a mean arterial pressure (MAP) ≥65 mmHg. Patients with hypotension should receive initial fluid challenge with approximately 30 mL/kg of balanced electrolyte solutions. However, iatrogenic volume overload should be avoided. If MAP remains < 65mmHg despite adequate volume norepinephrine is the first choice catecholamine. Oxygen should be delivered when oxygen saturation is below 90% to avoid hypoxemia. Intubation and invasive ventilation is reasonable in hemodynamically unstable or unconscious patients. Two blood cultures should be drawn immediately in every septic patient plus further microbiological test depending on the primary focus. After that broad spectrum antibiotics should be given (<60 min after diagnosis). Strong effort must be done to identify the primary source of sepsis including examination, history and different imaging technics. Physicians have to check actively, if the source can be controlled (<12h) by surgery or intervention. Ventilated patients must be monitored for depth of sedation, pain and delir with standardized tools (RASS, CPOT, BPS, CAM-ICU). Lung protective ventilation (TV 6-8ml/kg Ideal-BW, Pmax<30mbar, application of PEEP) is standard in septic patients. It should be combined with low sedation and early mobilisation to allow spontaneous breathing. Permanent monitoring for further organ dysfunction is mandatory. In case of sepsis induced kidney injury, early CRRT should be started with an average dose of 20-25ml/kg/h. Under CRRT many antibiotics must be given at a high dose to prevent underdosing. Concerning nutrition, enteral nutrition starting with 48h is recommended with a dose of 15-25kcal/kg. However, it remains uncertain if hypocaloric nutrition or parenteral application may be equivalent. Transfusion should be done restrictively (with a trigger Hb < 7g/dl). For the prevention of nosocomial sepsis high standard

  10. The Effects of Lung Protective Ventilation or Hypercapnic Acidosis on Gas Exchange and Lung Injury in Surfactant Deficient Rabbits

    PubMed Central

    Hummler, Helmut D.; Banke, Katharina; Wolfson, Marla R.; Buonocore, Giuseppe; Ebsen, Michael; Bernhard, Wolfgang; Tsikas, Dimitrios; Fuchs, Hans

    2016-01-01

    Background Permissive hypercapnia has been shown to reduce lung injury in subjects with surfactant deficiency. Experimental studies suggest that hypercapnic acidosis by itself rather than decreased tidal volume may be a key protective factor. Objectives To study the differential effects of a lung protective ventilatory strategy or hypercapnic acidosis on gas exchange, hemodynamics and lung injury in an animal model of surfactant deficiency. Methods 30 anesthetized, surfactant-depleted rabbits were mechanically ventilated (FiO2 = 0.8, PEEP = 7cmH2O) and randomized into three groups: Normoventilation-Normocapnia (NN)-group: tidal volume (Vt) = 7.5 ml/kg, target PaCO2 = 40 mmHg; Normoventilation-Hypercapnia (NH)-group: Vt = 7.5 ml/kg, target PaCO2 = 80 mmHg by increasing FiCO2; and a Hypoventilation-Hypercapnia (HH)-group: Vt = 4.5 ml/kg, target PaCO2 = 80 mmHg. Plasma lactate and interleukin (IL)-8 were measured every 2 h. Animals were sacrificed after 6 h to perform bronchoalveolar lavage (BAL), to measure lung wet-to-dry weight, lung tissue IL-8, and to obtain lung histology. Results PaO2 was significantly higher in the HH-group compared to the NN-group (p<0.05), with values of the NH-group between the HH- and NN-groups. Other markers of lung injury (wet-dry-weight, BAL-Protein, histology-score, plasma-IL-8 and lung tissue IL-8) resulted in significantly lower values for the HH-group compared to the NN-group and trends for the NH-group towards lower values compared to the NN-group. Lactate was significantly lower in both hypercapnia groups compared to the NN-group. Conclusion Whereas hypercapnic acidosis may have some beneficial effects, a significant effect on lung injury and systemic inflammatory response is dependent upon a lower tidal volume rather than resultant arterial CO2 tensions and pH alone. PMID:26840779

  11. Inhibitor of neuronal nitric oxide synthase improves gas exchange in ventilator-induced lung injury after pneumonectomy

    PubMed Central

    2012-01-01

    Background Mechanical ventilation with high tidal volumes may cause ventilator-induced lung injury (VILI) and enhanced generation of nitric oxide (NO). We demonstrated in sheep that pneumonectomy followed by injurious ventilation promotes pulmonary edema. We wished both to test the hypothesis that neuronal NOS (nNOS), which is distributed in airway epithelial and neuronal tissues, could be involved in the pathogenesis of VILI and we also aimed at investigating the influence of an inhibitor of nNOS on the course of VILI after pneumonectomy. Methods Anesthetized sheep underwent right pneumonectomy, mechanical ventilation with tidal volumes (VT) of 6 mL/kg and FiO2 0.5, and were subsequently randomized to a protectively ventilated group (PROTV; n = 8) keeping VT and FiO2 unchanged, respiratory rate (RR) 25 inflations/min and PEEP 4 cm H2O for the following 8 hrs; an injuriously ventilated group with VT of 12 mL/kg, zero end-expiratory pressure, and FiO2 and RR unchanged (INJV; n = 8) and a group, which additionally received the inhibitor of nNOS, 7-nitroindazole (NI) 1.0 mg/kg/h intravenously from 2 hours after the commencement of injurious ventilation (INJV + NI; n = 8). We assessed respiratory, hemodynamic and volumetric variables, including both the extravascular lung water index (EVLWI) and the pulmonary vascular permeability index (PVPI). We measured plasma nitrite/nitrate (NOx) levels and examined lung biopsies for lung injury score (LIS). Results Both the injuriously ventilated groups demonstrated a 2–3-fold rise in EVLWI and PVPI, with no significant effects of NI. In the INJV group, gas exchange deteriorated in parallel with emerging respiratory acidosis, but administration of NI antagonized the derangement of oxygenation and the respiratory acidosis significantly. NOx displayed no significant changes and NI exerted no significant effect on LIS in the INJV group. Conclusion Inhibition of nNOS improved gas exchange, but did not

  12. Repeated open endotracheal suctioning causes gradual desaturation but does not exacerbate lung injury compared to closed endotracheal suctioning in a rabbit model of ARDS

    PubMed Central

    2013-01-01

    Background Although endotracheal suctioning induces alveolar derecruitment during mechanical ventilation, it is not clear whether repeated endotracheal suctioning exacerbates lung injuries. The present study aimed to determine whether repeated open endotracheal suctioning (OS) exacerbates lung injury compared to closed endotracheal suctioning (CS) during mechanical ventilation in an animal model of acute respiratory distress syndrome (ARDS). Methods Briefly, thirty six Japanese white rabbits were initially ventilated in pressure-controlled mode with a constant tidal volume (6 mL/kg). Then, lung injury was induced by repeated saline lavage. The rabbits were divided into four groups, namely: a) OS; b) CS; c) control with ARDS only; d) and healthy control (HC) without ARDS. Animals in all the groups were then ventilated with positive end expiratory pressure (PEEP) at 10 cm H2O. CS was performed using 6 French-closed suctioning catheters connected to endotracheal tube under the following conditions: a) a suctioning time and pressure of 10 sec and 140 mm Hg, respectively; and b) a suction depth of 2 cm (length of adapter) plus tracheal tube. OS was performed using the same conditions described for CS, except the ventilator was disconnected from the animals. Each endotracheal suctioning was performed at an interval of 30 min. Results PaO2/FIO2 (P/F) ratio for CS, control and HC groups remained at >400 for 6 hours, whereas that of the OS group progressively declined to 300 (p < 0.05), with each suctioning. However, no difference was observed either in lung injury score (histology) or in the expression pattern of inflammatory cytokines (tumor necrosis factor-α and interleukin-6) after 6 hours between the OS and CS groups in the circulatory as well as the pulmonary tissues. Conclusions Progressive arterial desaturation under conditions of repeated endotracheal suctioning is greater in OS than in CS time-dependently. However, OS does not exacerbate lung injury

  13. PROCEEDINGS OF THE 2001 NATIONAL OILHEAT RESEARCH ALLIANCE TECHNOLOGY CONFERENCE HELD AT BROOKHAVEN NATIONAL LABORATORY, UPTON, N.Y., APRIL 30 - MAY 1, 2001.

    SciTech Connect

    MCDONALD, R.J.

    2001-04-30

    during the two-day program, all related to oil-heat technology and equipment, these will cover a range of research, developmental, and demonstration activities being conducted within the United States and Europe, including: (1) High-flow Fan Atomization Burner (HFAB) Development and Field Trials; (2) Field Test of the Flame Quality Monitor; (3) NORA/DOE/ BNL Oilheat Five-Year Research Plan; (4) US Department of Energy's Building Cooling Heating and Power for Buildings Program; (5) NORA Education Committee Report; (6) Marketing Oil Heat in Europe: A study in contrasts; (7) Diagnosing Burner Problems with Recorded Data ''The solution to any problem is obvious.. . once it is found''; (8) Variable Firing Rate Oil Burner Using Pulse Fuel Flow Control; (9) Oil-Fired Hydronic Heating Appliances with Reduced Electric Power Consumption and Battery Backup; (10) Peep Into The Nozzle Using Computational Fluid Dynamics; (11) Results of a Parametric Investigation of Spray Characteristics Using a HFAB Type Atomizer; (12) Progression and Improvements in the Design of Blue-flame Oil Burners; (13) Biodiesel as a Heating Oil Blend Stock; (14) Lab Tests of Biodiesel Blends in Residential Heating Equipment; (15) Alternative Fuel Oils and the Effect of Selected Properties in Combustion; (16) New York State Premium Low-Sulfur Heating Fuel Marketplace Demonstration; and (17)The Need for a New Fuel Oil Stability Specification.

  14. [From isoflurane to perfluorohexane? Perfluorocarbons--therapeutic strategies in acute lung failure].

    PubMed

    Ragaller, M; Bleyl, J U; Koch, T; Albrecht, D M

    2000-04-01

    The introduction of Perfluorochemicals into medicine and especially into the treatment of severe lung injury is a fascinating scientific task. Many recall the famous experiments from Clark et al. in 1966 when he demonstrated "liquidventilation with perfluorocarbons" in the mammal species for the first time. After this hallmark, perfluorocarbons were subsequently introduced in research of acute lung injury by the techniques of Total- and Partial-Liquid-Ventilation (TLV; PLV). Perfluorocarbons (saturated organofluorids) have unique chemical and physical properties which made them attractive substances for intraalveolar application. The strong C-F bindings in the perfluorocarbon molecules are responsible for their chemical stability, biochemical inertness, high capacity to dissolve respiratory gases, low surface tension and high vapor pressures. Furthermore, the high density of the PFC lead to radio-opacity and their distribution to dependent lung areas. The efficacy of PFC liquid, applied by TLV/PLV has been demonstrated in numerous animal studies using different models of acute lung injury. Currently, several mechanisms of action of perfluorocarbon fluids in acute lung injury are discussed: recruitment of atelectatic alveoli, prevention of endexpiratory collapse of alveoli ("liquid PEEP"), redistribution of perfusion, oxygen transport, surfactant like effects and decrease of inflammation. Since total liquid ventilation has been used only in experimental models of lung injury, partial liquid ventilation has been introduced successfully into clinical trials (phase I-II). However, the results of the first randomised, controlled study of PLV in 90 adult patients suffering from severe respiratory failure (ALI/ARDS) showed no differences between PLV and conventional treatment. Furthermore, the instillation of relatively large amounts of liquid into the lungs poses several technical challenges and may be associated with complications such as liquithoraces, pneumothoraces

  15. Sustained inflation and incremental mean airway pressure trial during conventional and high-frequency oscillatory ventilation in a large porcine model of acute respiratory distress syndrome

    PubMed Central

    Muellenbach, Ralf M; Kredel, Markus; Zollhoefer, Bernd; Wunder, Christian; Roewer, Norbert; Brederlau, Joerg

    2006-01-01

    Background To compare the effect of a sustained inflation followed by an incremental mean airway pressure trial during conventional and high-frequency oscillatory ventilation on oxygenation and hemodynamics in a large porcine model of early acute respiratory distress syndrome. Methods Severe lung injury (Ali) was induced in 18 healthy pigs (55.3 ± 3.9 kg, mean ± SD) by repeated saline lung lavage until PaO2 decreased to less than 60 mmHg. After a stabilisation period of 60 minutes, the animals were randomly assigned to two groups: Group 1 (Pressure controlled ventilation; PCV): FIO2 = 1.0, PEEP = 5 cmH2O, VT = 6 ml/kg, respiratory rate = 30/min, I:E = 1:1; group 2 (High-frequency oscillatory ventilation; HFOV): FIO2 = 1.0, Bias flow = 30 l/min, Amplitude = 60 cmH2O, Frequency = 6 Hz, I:E = 1:1. A sustained inflation (SI; 50 cmH2O for 60s) followed by an incremental mean airway pressure (mPaw) trial (steps of 3 cmH2O every 15 minutes) were performed in both groups until PaO2 no longer increased. This was regarded as full lung inflation. The mPaw was decreased by 3 cmH2O and the animals reached the end of the study protocol. Gas exchange and hemodynamic data were collected at each step. Results The SI led to a significant improvement of the PaO2/FiO2-Index (HFOV: 200 ± 100 vs. PCV: 58 ± 15 and TAli: 57 ± 12; p < 0.001) and PaCO2-reduction (HFOV: 42 ± 5 vs. PCV: 62 ± 13 and TAli: 55 ± 9; p < 0.001) during HFOV compared to lung injury and PCV. Augmentation of mPaw improved gas exchange and pulmonary shunt fraction in both groups, but at a significant lower mPaw in the HFOV treated animals. Cardiac output was continuously deteriorating during the recruitment manoeuvre in both study groups (HFOV: TAli: 6.1 ± 1 vs. T75: 3.4 ± 0.4; PCV: TAli: 6.7 ± 2.4 vs. T75: 4 ± 0.5; p < 0.001). Conclusion A sustained inflation followed by an incremental mean airway pressure trial in HFOV improved oxygenation at a lower mPaw than during conventional lung protective