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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. 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.

  3. PEEP titration during prone positioning for acute respiratory distress syndrome.

    PubMed

    Beitler, Jeremy R; Guérin, Claude; Ayzac, Louis; Mancebo, Jordi; Bates, Dina M; Malhotra, Atul; Talmor, Daniel

    2015-01-01

    No major trial evaluating prone positioning for acute respiratory distress syndrome (ARDS) has incorporated a high-positive end-expiratory pressure (high-PEEP) strategy despite complementary physiological rationales. We evaluated generalizability of three recent proning trials to patients receiving a high-PEEP strategy. All trials employed a relatively low-PEEP strategy. After protocol ventilator settings were initiated and the patient was positioned per treatment assignment, post-intervention PEEP was not more than 5 cm H2O in 16.7 % and not more than 10 cm H2O in 66.0 % of patients. Post-intervention PEEP would have been nearly twice the set PEEP had a high-PEEP strategy been employed. Use of either proning or high-PEEP likely improves survival in moderate-severe ARDS; the role for both concomitantly remains unknown.

  4. 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

  5. Automatic detection of AutoPEEP during controlled mechanical ventilation

    PubMed Central

    2012-01-01

    Background Dynamic hyperinflation, hereafter called AutoPEEP (auto-positive end expiratory pressure) with some slight language abuse, is a frequent deleterious phenomenon in patients undergoing mechanical ventilation. Although not readily quantifiable, AutoPEEP can be recognized on the expiratory portion of the flow waveform. If expiratory flow does not return to zero before the next inspiration, AutoPEEP is present. This simple detection however requires the eye of an expert clinician at the patient’s bedside. An automatic detection of AutoPEEP should be helpful to optimize care. Methods In this paper, a platform for automatic detection of AutoPEEP based on the flow signal available on most of recent mechanical ventilators is introduced. The detection algorithms are developed on the basis of robust non-parametric hypothesis testings that require no prior information on the signal distribution. In particular, two detectors are proposed: one is based on SNT (Signal Norm Testing) and the other is an extension of SNT in the sequential framework. The performance assessment was carried out on a respiratory system analog and ex-vivo on various retrospectively acquired patient curves. Results The experiment results have shown that the proposed algorithm provides relevant AutoPEEP detection on both simulated and real data. The analysis of clinical data has shown that the proposed detectors can be used to automatically detect AutoPEEP with an accuracy of 93% and a recall (sensitivity) of 90%. Conclusions The proposed platform provides an automatic early detection of AutoPEEP. Such functionality can be integrated in the currently used mechanical ventilator for continuous monitoring of the patient-ventilator interface and, therefore, alleviate the clinician task. PMID:22715924

  6. 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

  7. 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)

  8. High PEEP in acute respiratory distress syndrome: quantitative evaluation between improved arterial oxygenation and decreased oxygen delivery

    PubMed Central

    Das, A.; Haque, M.; Wang, W.; Bates, D. G.; Hardman, J. G.

    2016-01-01

    Background. Positive end-expiratory pressure (PEEP) is widely used to improve oxygenation and prevent alveolar collapse in mechanically ventilated patients with the acute respiratory distress syndrome (ARDS). Although PEEP improves arterial oxygenation predictably, high-PEEP strategies have demonstrated equivocal improvements in ARDS-related mortality. The effect of PEEP on tissue oxygen delivery is poorly understood and is difficult to quantify or investigate in the clinical environment. Methods. We investigated the effects of PEEP on tissue oxygen delivery in ARDS using a new, high-fidelity, computational model with highly integrated respiratory and cardiovascular systems. The model was configured to replicate published clinical trial data on the responses of 12 individual ARDS patients to changes in PEEP. These virtual patients were subjected to increasing PEEP levels during a lung-protective ventilation strategy (0–20 cm H2O). Measured variables included arterial oxygenation, cardiac output, peripheral oxygen delivery, and alveolar strain. Results. As PEEP increased, tissue oxygen delivery decreased in all subjects (mean reduction of 25% at 20 cm H2O PEEP), despite an increase in arterial oxygen tension (mean increase 6.7 kPa at 20 cm H2O PEEP). Changes in arterial oxygenation and tissue oxygen delivery differed between subjects but showed a consistent pattern. Static and dynamic alveolar strain decreased in all patients as PEEP increased. Conclusions. Incremental PEEP in ARDS appears to protect alveoli and improve arterial oxygenation, but also appears to impair tissue oxygen delivery significantly because of reduced cardiac output. We propose that this trade-off may explain the poor improvements in mortality associated with high-PEEP ventilation strategies. PMID:27799180

  9. 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

  10. 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.

  11. 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

  12. Effect of PEEP, blood volume, and inspiratory hold maneuvers on venous return.

    PubMed

    Berger, David; Moller, Per W; Weber, Alberto; Bloch, Andreas; Bloechlinger, Stefan; Haenggi, Matthias; Sondergaard, Soren; Jakob, Stephan M; Magder, Sheldon; Takala, Jukka

    2016-09-01

    According to Guyton's model of circulation, mean systemic filling pressure (MSFP), right atrial pressure (RAP), and resistance to venous return (RVR) determine venous return. MSFP has been estimated from inspiratory hold-induced changes in RAP and blood flow. We studied the effect of positive end-expiratory pressure (PEEP) and blood volume on venous return and MSFP in pigs. MSFP was measured by balloon occlusion of the right atrium (MSFPRAO), and the MSFP obtained via extrapolation of pressure-flow relationships with airway occlusion (MSFPinsp_hold) was extrapolated from RAP/pulmonary artery flow (QPA) relationships during inspiratory holds at PEEP 5 and 10 cmH2O, after bleeding, and in hypervolemia. MSFPRAO increased with PEEP [PEEP 5, 12.9 (SD 2.5) mmHg; PEEP 10, 14.0 (SD 2.6) mmHg, P = 0.002] without change in QPA [2.75 (SD 0.43) vs. 2.56 (SD 0.45) l/min, P = 0.094]. MSFPRAO decreased after bleeding and increased in hypervolemia [10.8 (SD 2.2) and 16.4 (SD 3.0) mmHg, respectively, P < 0.001], with parallel changes in QPA Neither PEEP nor volume state altered RVR (P = 0.489). MSFPinsp_hold overestimated MSFPRAO [16.5 (SD 5.8) vs. 13.6 (SD 3.2) mmHg, P = 0.001; mean difference 3.0 (SD 5.1) mmHg]. Inspiratory holds shifted the RAP/QPA relationship rightward in euvolemia because inferior vena cava flow (QIVC) recovered early after an inspiratory hold nadir. The QIVC nadir was lowest after bleeding [36% (SD 24%) of preinspiratory hold at 15 cmH2O inspiratory pressure], and the QIVC recovery was most complete at the lowest inspiratory pressures independent of volume state [range from 80% (SD 7%) after bleeding to 103% (SD 8%) at PEEP 10 cmH2O of QIVC before inspiratory hold]. The QIVC recovery thus defends venous return, possibly via hepatosplanchnic vascular waterfall.

  13. Effect of PEEP, blood volume, and inspiratory hold maneuvers on venous return.

    PubMed

    Berger, David; Moller, Per W; Weber, Alberto; Bloch, Andreas; Bloechlinger, Stefan; Haenggi, Matthias; Sondergaard, Soren; Jakob, Stephan M; Magder, Sheldon; Takala, Jukka

    2016-09-01

    According to Guyton's model of circulation, mean systemic filling pressure (MSFP), right atrial pressure (RAP), and resistance to venous return (RVR) determine venous return. MSFP has been estimated from inspiratory hold-induced changes in RAP and blood flow. We studied the effect of positive end-expiratory pressure (PEEP) and blood volume on venous return and MSFP in pigs. MSFP was measured by balloon occlusion of the right atrium (MSFPRAO), and the MSFP obtained via extrapolation of pressure-flow relationships with airway occlusion (MSFPinsp_hold) was extrapolated from RAP/pulmonary artery flow (QPA) relationships during inspiratory holds at PEEP 5 and 10 cmH2O, after bleeding, and in hypervolemia. MSFPRAO increased with PEEP [PEEP 5, 12.9 (SD 2.5) mmHg; PEEP 10, 14.0 (SD 2.6) mmHg, P = 0.002] without change in QPA [2.75 (SD 0.43) vs. 2.56 (SD 0.45) l/min, P = 0.094]. MSFPRAO decreased after bleeding and increased in hypervolemia [10.8 (SD 2.2) and 16.4 (SD 3.0) mmHg, respectively, P < 0.001], with parallel changes in QPA Neither PEEP nor volume state altered RVR (P = 0.489). MSFPinsp_hold overestimated MSFPRAO [16.5 (SD 5.8) vs. 13.6 (SD 3.2) mmHg, P = 0.001; mean difference 3.0 (SD 5.1) mmHg]. Inspiratory holds shifted the RAP/QPA relationship rightward in euvolemia because inferior vena cava flow (QIVC) recovered early after an inspiratory hold nadir. The QIVC nadir was lowest after bleeding [36% (SD 24%) of preinspiratory hold at 15 cmH2O inspiratory pressure], and the QIVC recovery was most complete at the lowest inspiratory pressures independent of volume state [range from 80% (SD 7%) after bleeding to 103% (SD 8%) at PEEP 10 cmH2O of QIVC before inspiratory hold]. The QIVC recovery thus defends venous return, possibly via hepatosplanchnic vascular waterfall. PMID:27422991

  14. 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

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

    PubMed Central

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

    2016-01-01

    Abstract 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

  16. Prediction of hemodynamic changes towards PEEP titrations at different volemic levels using a minimal cardiovascular model.

    PubMed

    Starfinger, C; Chase, J G; Hann, C E; Shaw, G M; Lambert, P; Smith, B W; Sloth, E; Larsson, A; Andreassen, S; Rees, S

    2008-08-01

    A cardiovascular system model and parameter identification method have previously been validated for porcine experiments of induced pulmonary embolism and positive end-expiratory pressure (PEEP) titrations, accurately tracking all the main hemodynamic trends. In this research, the model and parameter identification process are further validated by predicting the effect of intervention. An overall population-specific rule linking specific model parameters to increases in PEEP is formulated to predict the hemodynamic effects on arterial pressure, pulmonary artery pressure and stroke volume. Hemodynamic changes are predicted for an increase from 0 to 10 cm H(2)O with median absolute percentage errors less than 7% (systolic pressures) and 13% (stroke volume). For an increase from 10 to 20 cm H(2)O median absolute percentage errors are less than 11% (systolic pressures) and 17% (stroke volume). These results validate the general applicability of such a rule, which is not pig-specific, but holds over for all analyzed pigs. This rule enables physiological simulation and prediction of patient response. Overall, the prediction accuracy achieved represents a further clinical validation of these models, methods and overall approach to cardiovascular diagnosis and therapy guidance.

  17. 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…

  18. 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.

  19. Model-based identification of PEEP titrations during different volemic levels.

    PubMed

    Starfinger, C; Chase, J G; Hann, C E; Shaw, G M; Lambert, P; Smith, B W; Sloth, E; Larsson, A; Andreassen, S; Rees, S

    2008-08-01

    A cardiovascular system (CVS) model has previously been validated in simulated cardiac and circulatory disease states. It has also been shown to accurately capture all main hemodynamic trends in a porcine model of pulmonary embolism. In this research, a slightly extended CVS model and parameter identification process are presented and validated in a porcine experiment of positive end-expiratory pressure (PEEP) titrations at different volemic levels. The model is extended to more physiologically represent the separation of venous and arterial circulation. Errors for the identified model are within 5% when re-simulated and compared to clinical data. All identified parameter trends match clinically expected changes. This work represents another clinical validation of the underlying fundamental CVS model, and the methods and approach of using them for cardiovascular diagnosis in critical care.

  20. Semantic analysis according to Peep Koort--a substance-oriented research methodology.

    PubMed

    Sivonen, Kerstin; Kasén, Anne; Eriksson, Katie

    2010-12-01

    The aim of this article is to describe the hermeneutic semantic analysis created by professor Peep Koort (1920-1977) and to discuss it as a methodology for research within caring science. The methodology is developed with a hermeneutic approach that differs from the traditions of semantic analysis in philosophy or linguistics. The research objects are core concepts and theoretical constructs (originally within the academic discipline of education science, later on within the academic discipline of caring science), focusing deeper understanding of essential meaning content when developing a discipline. The qualitative methodology of hermeneutic semantic analysis is described step by step as created by Koort, interpreted and developed by the authors. An etymological investigation and an analysis of synonymy between related concepts within a conceptual family guides the researcher to understand and discriminate conceptual dimensions of meaning content connected to the word studied, thus giving opportunities to summarise it in a theoretical definition, a discovery that can be tested in varying contexts. From a caring science perspective, we find the hermeneutic methodology of semantic analysis fruitful and suitable for researchers developing their understanding of core concepts and theoretical constructs connected to the development of the academic discipline.

  1. 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

  2. Multivariable fractional polynomial interaction to investigate continuous effect modifiers in a meta-analysis on higher versus lower PEEP for patients with ARDS

    PubMed Central

    Kasenda, Benjamin; Sauerbrei, Willi; Royston, Patrick; Mercat, Alain; Slutsky, Arthur S; Cook, Deborah; Guyatt, Gordon H; Brochard, Laurent; Richard, Jean-Christophe M; Stewart, Thomas E; Meade, Maureen; Briel, Matthias

    2016-01-01

    Objectives A recent individual patient data (IPD) meta-analysis suggested that patients with moderate or severe acute respiratory distress syndrome (ARDS) benefit from higher positive end-expiratory pressure (PEEP) ventilation strategies. However, thresholds for continuous variables (eg, hypoxaemia) are often arbitrary and linearity assumptions in regression approaches may not hold; the multivariable fractional polynomial interaction (MFPI) approach can address both problems. The objective of this study was to apply the MFPI approach to investigate interactions between four continuous patient baseline variables and higher versus lower PEEP on clinical outcomes. Setting Pooled data from three randomised trials in intensive care identified by a systematic review. Participants 2299 patients with acute lung injury requiring mechanical ventilation. Interventions Higher (N=1136) versus lower PEEP (N=1163) ventilation strategy. Outcome measures Prespecified outcomes included mortality, time to death and time-to-unassisted breathing. We examined the following continuous baseline characteristics as potential effect modifiers using MFPI: PaO2/FiO2 (arterial partial oxygen pressure/ fraction of inspired oxygen), oxygenation index, respiratory system compliance (tidal volume/(inspiratory plateau pressure−PEEP)) and body mass index (BMI). Results We found that for patients with PaO2/FiO2 below 150 mm Hg, but above 100 mm Hg or an oxygenation index above 12 (moderate ARDS), higher PEEP reduces hospital mortality, but the beneficial effect appears to level off for patients with very severe ARDS. Patients with mild ARDS (PaO2/FiO2 above 200 mm Hg or an oxygenation index below 10) do not seem to benefit from higher PEEP and might even be harmed. For patients with a respiratory system compliance above 40 mL/cm H2O or patients with a BMI above 35 kg/m2, we found a trend towards reduced mortality with higher PEEP, but there is very weak statistical confidence in

  3. 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…

  4. 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

  5. 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.

  6. 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

  7. 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

  8. 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.

  9. 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…

  10. Another peep behind the veil.

    PubMed

    McKie, J; Kuhse, H; Richardson, J; Singer, P

    1996-08-01

    Harris argues that if QALYs are used only 50% of the population will be eligible for survival, whereas if random methods of allocation are used 100% will be eligible. We argue that this involves an equivocation in the use of "eligible", and provides no support for the random method. There is no advantage in having a 100% chance of being "eligible" for survival behind a veil of ignorance if you still only have a 50% chance of survival once the veil is lifted. A 100% chance of a 50% chance is still only a 50% chance. We also argue that Harris provides no plausible way of dealing with the criticism that his random method of allocation may result in the squandering of resources.

  11. 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

  12. 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.

  13. 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…

  14. "Scientific peep show": the human body in contemporary science museums.

    PubMed

    Canadelli, Elena

    2011-01-01

    The essay focuses on the discourse about the human body developed by contemporary science museums with educational and instructive purposes directed at the general public. These museums aim mostly at mediating concepts such as health and prevention. The current scenario is linked with two examples of past museums: the popular anatomical museums which emerged during the 19th century and the health museums thrived between 1910 and 1940. On the museological path about the human body self-care we went from the emotionally involving anatomical Venuses to the inexpressive Transparent Man, from anatomical specimens of ill organs and deformed subjects to the mechanical and electronic models of the healthy body. Today the body is made transparent by the new medical diagnostics and by the latest discoveries of endoscopy. The way museums and science centers presently display the human body involves computers, 3D animation, digital technologies, hands-on models of large size human parts.

  15. ``Peeps,'' cream, heads, and food coloring in a vacuum jar

    NASA Astrophysics Data System (ADS)

    DePino, Andrew

    2001-01-01

    This note describes some methods of adding interest to the standard vacuum jar demonstrations. Marshmallow animals, shaving cream, doll heads, and food coloring add some spark to these demos. These new twists have been well received by the students.

  16. 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).

  17. 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

  18. 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)

  19. 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…

  20. Giving peeps to my props: Using 3D printing to shed new light on particle transport in fractured rock.

    NASA Astrophysics Data System (ADS)

    Walsh, S. D.; Du Frane, W. L.; Vericella, J. J.; Aines, R. D.

    2014-12-01

    Smart tracers and smart proppants promise new methods for sensing and manipulating rock fractures. However, the correct use and interpretation of these technologies relies on accurate models of their transport. Even for less exotic particles, the factors controlling particle transport through fractures are poorly understood. In this presentation, we will describe ongoing research at Lawrence Livermore National Laboratory into the transport properties of particles in natural rock fractures. Using three dimensional printing techniques, we create clear-plastic reproductions of real-world fracture surfaces, thereby enabling direct observation of the particle movement. We will also discuss how particle tracking of dense particle packs can be further enhanced by using such specially tailored flow cells in combination with micro-encapsulated tracer particles. Experimental results investigating the transport behavior of smart tracers and proppants close to the neutrally buoyant limit will be presented and we will describe how data from these experiments can be used to improve large-scale models of particle transport in fractures. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  1. 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

  2. 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

  3. 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.

  4. Positive end-expiratory pressure at minimal respiratory elastance represents the best compromise between mechanical stress and lung aeration in oleic acid induced lung injury

    PubMed Central

    Carvalho, Alysson Roncally S; Jandre, Frederico C; Pino, Alexandre V; Bozza, Fernando A; Salluh, Jorge; Rodrigues, Rosana; Ascoli, Fabio O; Giannella-Neto, Antonio

    2007-01-01

    Introduction Protective ventilatory strategies have been applied to prevent ventilator-induced lung injury in patients with acute lung injury (ALI). However, adjustment of positive end-expiratory pressure (PEEP) to avoid alveolar de-recruitment and hyperinflation remains difficult. An alternative is to set the PEEP based on minimizing respiratory system elastance (Ers) by titrating PEEP. In the present study we evaluate the distribution of lung aeration (assessed using computed tomography scanning) and the behaviour of Ers in a porcine model of ALI, during a descending PEEP titration manoeuvre with a protective low tidal volume. Methods PEEP titration (from 26 to 0 cmH2O, with a tidal volume of 6 to 7 ml/kg) was performed, following a recruitment manoeuvre. At each PEEP, helical computed tomography scans of juxta-diaphragmatic parts of the lower lobes were obtained during end-expiratory and end-inspiratory pauses in six piglets with ALI induced by oleic acid. The distribution of the lung compartments (hyperinflated, normally aerated, poorly aerated and non-aerated areas) was determined and the Ers was estimated on a breath-by-breath basis from the equation of motion of the respiratory system using the least-squares method. Results Progressive reduction in PEEP from 26 cmH2O to the PEEP at which the minimum Ers was observed improved poorly aerated areas, with a proportional reduction in hyperinflated areas. Also, the distribution of normally aerated areas remained steady over this interval, with no changes in non-aerated areas. The PEEP at which minimal Ers occurred corresponded to the greatest amount of normally aerated areas, with lesser hyperinflated, and poorly and non-aerated areas. Levels of PEEP below that at which minimal Ers was observed increased poorly and non-aerated areas, with concomitant reductions in normally inflated and hyperinflated areas. Conclusion The PEEP at which minimal Ers occurred, obtained by descending PEEP titration with a protective

  5. 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

  6. [Intraoperative protective ventilation reduces postoperative pulmonary complications - PRO].

    PubMed

    Güldner, Andreas; Gama de Abreu, Marcelo

    2015-09-01

    Postoperative pulmonary complications add to higher mortality and morbidity. This risk could be lowered with intraoperative protective ventilation, especially with low tidal volumes. The application of PEEP and the use of recruitment maneuvers can enhance the lung function during surgery, but can also cause haemodynamic instability. In patients with open abdominal surgery and no lung damage or obesity, PEEP and recruitment maneuvers have no protective effect against postoperative pulmonary complications. It is still unclear, wether the use of intraoperative PEEP in other patient groups and during different surgery procedures is relevant for lung protection.

  7. 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

  8. An avian vocalization detector.

    PubMed

    Severns, M; Gray, L; Rubel, E W

    1985-05-01

    A simple circuit to detect avian vocalizations is described. Adjustments of five different controls (frequency, bandwidth, amplitude, duration and spacing) allow the circuit to accurately detect the vocalizations of different ages and species of birds. Analyses of over 4000 peeps and 500 inter-peep intervals from 40 chicks and 16 ducklings showed that the circuit and an experienced observer agreed closely in the timing and counting of vocalizations.

  9. High positive end-expiratory pressure: only a dam against oedema formation?

    PubMed Central

    2013-01-01

    Introduction Healthy piglets ventilated with no positive end-expiratory pressure (PEEP) and with tidal volume (VT) close to inspiratory capacity (IC) develop fatal pulmonary oedema within 36 h. In contrast, those ventilated with high PEEP and low VT, resulting in the same volume of gas inflated (close to IC), do not. If the real threat to the blood-gas barrier is lung overinflation, then a similar damage will occur with the two settings. If PEEP only hydrostatically counteracts fluid filtration, then its removal will lead to oedema formation, thus revealing the deleterious effects of overinflation. Methods Following baseline lung computed tomography (CT), five healthy piglets were ventilated with high PEEP (volume of gas around 75% of IC) and low VT (25% of IC) for 36 h. PEEP was then suddenly zeroed and low VT was maintained for 18 h. Oedema was diagnosed if final lung weight (measured on a balance following autopsy) exceeded the initial one (CT). Results Animals were ventilated with PEEP 18 ± 1 cmH2O (volume of gas 875 ± 178 ml, 89 ± 7% of IC) and VT 213 ± 10 ml (22 ± 5% of IC) for the first 36 h, and with no PEEP and VT 213 ± 10 ml for the last 18 h. On average, final lung weight was not higher, and actually it was even lower, than the initial one (284 ± 62 vs. 347 ± 36 g; P = 0.01). Conclusions High PEEP (and low VT) do not merely impede fluid extravasation but rather preserve the integrity of the blood-gas barrier in healthy lungs. PMID:23844622

  10. 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

  11. Effects of descending positive end-expiratory pressure on lung mechanics and aeration in healthy anaesthetized piglets

    PubMed Central

    Carvalho, Alysson Roncally S; Jandre, Frederico C; Pino, Alexandre V; Bozza, Fernando A; Salluh, Jorge I; Rodrigues, Rosana S; Soares, João HN; Giannella-Neto, Antonio

    2006-01-01

    Introduction Atelectasis and distal airway closure are common clinical entities of general anaesthesia. These two phenomena are expected to reduce the ventilation of dependent lung regions and represent major causes of arterial oxygenation impairment in anaesthetic conditions. The behaviour of the elastance of the respiratory system (Ers), as well as the lung aeration assessed by computed tomography (CT) scan, was evaluated during a descendent positive end-expiratory pressure (PEEP) titration. This work sought to evaluate the potential usefulness of Ers monitoring to set the PEEP in order to prevent tidal recruitment and hyperinflation of healthy lungs under general anaesthesia. Methods PEEP titration (from 16 to 0 cmH2O, tidal volume of 8 ml/kg) was performed, and at each PEEP, CT scans were obtained during end-expiratory and end-inspiratory pauses in six healthy, anaesthetized and paralyzed piglets. The distribution of lung aeration was determined and the tidal re-aeration was calculated as the difference between end-expiratory and end-inspiratory poorly aerated and normally aerated areas. Similarly, tidal hyperinflation was obtained as the difference between end-inspiratory and end-expiratory hyperinflated areas. Ers was estimated from the equation of motion of the respiratory system during all PEEP titration with the least-squares method. Results Hyperinflated areas decreased from PEEP 16 to 0 cmH2O (ranges decreased from 24–62% to 1–7% at end-expiratory pauses and from 44–73% to 4–17% at end-inspiratory pauses) whereas normally aerated areas increased (from 30–66% to 72–83% at end-expiratory pauses and from 19–48% to 73–77% at end-inspiratory pauses). From 16 to 8 cmH2O, Ers decreased with a corresponding reduction in tidal hyperinflation. A flat minimum of Ers was observed from 8 to 4 cmH2O. For PEEP below 4 cmH2O, Ers increased in association with a rise in tidal re-aeration and a flat maximum of the normally aerated areas. Conclusion In

  12. Positive end-expiratory pressure oscillation facilitates brain vascular reactivity monitoring.

    PubMed

    Brady, Ken M; Easley, R Blaine; Kibler, Kathleen; Kaczka, David W; Andropoulos, Dean; Fraser, Charles D; Smielewski, Peter; Czosnyka, Marek; Adams, Gerald J; Rhee, Christopher J; Rusin, Craig G

    2012-11-01

    The pressure reactivity index (PRx) identifies optimal cerebral perfusion pressure after traumatic brain injury. We describe a method to improve PRx precision by induced variations in arterial blood pressure (ABP) using positive end-expiratory pressure (PEEP) modulation (iPRx). Neonatal swine (n = 10) were ventilated with static PEEP and then with PEEP oscillated between 5 and 10 cmH(2)O at a frequency of 1/min. PRx was recorded as a moving correlation coefficient between ABP and intracranial pressure (ICP) from spontaneous ABP activity (0.05-0.003 Hz) during static PEEP. iPRx was similarly recorded with PEEP oscillation-induced ABP waves. The lower limit of autoregulation (LLA) was delineated with continuous cortical laser Doppler flux monitoring. PEEP oscillation increased autoregulation-monitoring precision. The ratios of median absolute deviations to range of possible values for the PRx and iPRx were 9.5% (8.3-13.7%) and 6.2% (4.2-8.7%), respectively (P = 0.006; median, interquartile range). The phase-angle difference between ABP and ICP above LLA was 161° (150°-166°) and below LLA, -31° (-42° to 12°, P < 0.0001). iPRx above LLA was -0.42 (-0.67 to -0.29) and below LLA, 0.32 (0.22-0.43, P = 0.0004). A positive iPRx was 97% specific and 91% sensitive for perfusion pressure below LLA. PEEP oscillation caused stable, low-frequency ABP oscillations that reduced noise in the PRx. Safe translation of these findings to clinical settings is expected to yield more accurate and rapid delineation of individualized optimal perfusion-pressure goals for patients.

  13. 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

  14. 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.

  15. Effects on lung stress of position and different doses of perfluorocarbon in a model of ARDS.

    PubMed

    López-Aguilar, Josefina; Lucangelo, Umberto; Albaiceta, Guillermo M; Nahum, Avi; Murias, Gastón; Cañizares, Rosario; Oliva, Joan Carles; Romero, Pablo V; Blanch, Lluís

    2015-05-01

    We determined whether the combination of low dose partial liquid ventilation (PLV) with perfluorocarbons (PFC) and prone positioning improved lung function while inducing minimal stress. Eighteen pigs with acute lung injury were assigned to conventional mechanical ventilation (CMV) or PLV (5 or 10 ml/kg of PFC). Positive end-expiratory pressure (PEEP) trials in supine and prone positions were performed. Data were analyzed by a multivariate polynomial regression model. The interplay between PLV and position depended on the PEEP level. In supine PLV dampened the stress induced by increased PEEP during the trial. The PFC dose of 5 ml/kg was more effective than the dose 10 ml/kg. This effect was not observed in prone. Oxygenation was significantly higher in prone than in supine position mainly at lower levels of PEEP. In conclusion, MV settings should take both gas exchange and stress/strain into account. When protective CMV fails, rescue strategies combining prone positioning and PLV with optimal PEEP should improve gas exchange with minimal stress.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. [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.

  1. 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

  2. Positive end expiratory pressure in acute and chronic respiratory distress.

    PubMed

    Greenough, A; Chan, V; Hird, M F

    1992-03-01

    The optimum level of positive end expiratory pressure (PEEP) was determined in 16 infants with respiratory distress syndrome (median gestational age 29 weeks, median postnatal age 1 day) and in 16 infants with chronic respiratory distress (median gestational age 25 weeks, median postnatal age 15 days). All infants were studied at a PEEP sequence of 3, 0, 3, 6, and 3 cm H2O, all other ventilator parameters being kept constant. Each PEEP level was maintained for 20 minutes and at the end of each period arterial blood gas was checked. During acute respiratory distress syndrome there were no significant changes in oxygenation but arterial carbon dioxide tension (PaCO2) significantly decreased from a mean of 4.93 kPa at 3 cm H2O to 4.40 kPa at 0 cm H2O and increased to a mean of 5.87 kPa at 6 cm H2O. In the infants with chronic respiratory distress, oxygenation fell from a mean of 8.66 kPa at 3 cm H2O to 6.40 kPa at 0 cm H2O and improved at 6 cm H2O to a mean of 10.50 kPa. There were no significant changes in PaCO2. We conclude that addition of PEEP, up to 6 cm H2O, may be useful even after the first week of life. High levels of PEEP, however, have previously been reported, in certain infants, to result in circulatory disturbance. It is therefore important to assess the use of 6 cm H2O PEEP in a controlled study of longer term clinical outcome.

  3. 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

  4. Positive end expiratory pressure in acute and chronic respiratory distress.

    PubMed Central

    Greenough, A; Chan, V; Hird, M F

    1992-01-01

    The optimum level of positive end expiratory pressure (PEEP) was determined in 16 infants with respiratory distress syndrome (median gestational age 29 weeks, median postnatal age 1 day) and in 16 infants with chronic respiratory distress (median gestational age 25 weeks, median postnatal age 15 days). All infants were studied at a PEEP sequence of 3, 0, 3, 6, and 3 cm H2O, all other ventilator parameters being kept constant. Each PEEP level was maintained for 20 minutes and at the end of each period arterial blood gas was checked. During acute respiratory distress syndrome there were no significant changes in oxygenation but arterial carbon dioxide tension (PaCO2) significantly decreased from a mean of 4.93 kPa at 3 cm H2O to 4.40 kPa at 0 cm H2O and increased to a mean of 5.87 kPa at 6 cm H2O. In the infants with chronic respiratory distress, oxygenation fell from a mean of 8.66 kPa at 3 cm H2O to 6.40 kPa at 0 cm H2O and improved at 6 cm H2O to a mean of 10.50 kPa. There were no significant changes in PaCO2. We conclude that addition of PEEP, up to 6 cm H2O, may be useful even after the first week of life. High levels of PEEP, however, have previously been reported, in certain infants, to result in circulatory disturbance. It is therefore important to assess the use of 6 cm H2O PEEP in a controlled study of longer term clinical outcome. PMID:1575557

  5. Plasma-derived human C1-esterase inhibitor does not prevent mechanical ventilation-induced pulmonary complement activation in a rat model of Streptococcus pneumoniae pneumonia.

    PubMed

    de Beer, F M; Aslami, H; Hoeksma, J; van Mierlo, G; Wouters, D; Zeerleder, S; Roelofs, J J T H; Juffermans, N P; Schultz, M J; Lagrand, W K

    2014-11-01

    Mechanical ventilation has the potential to cause lung injury, and the role of complement activation herein is uncertain. We hypothesized that inhibition of the complement cascade by administration of plasma-derived human C1-esterase inhibitor (C1-INH) prevents ventilation-induced pulmonary complement activation, and as such attenuates lung inflammation and lung injury in a rat model of Streptococcus pneumoniae pneumonia. Forty hours after intratracheal challenge with S. pneumoniae causing pneumonia rats were subjected to ventilation with lower tidal volumes and positive end-expiratory pressure (PEEP) or high tidal volumes without PEEP, after an intravenous bolus of C1-INH (200 U/kg) or placebo (saline). After 4 h of ventilation blood, broncho-alveolar lavage fluid and lung tissue were collected. Non-ventilated rats with S. pneumoniae pneumonia served as controls. While ventilation with lower tidal volumes and PEEP slightly amplified pneumonia-induced complement activation in the lungs, ventilation with higher tidal volumes without PEEP augmented local complement activation more strongly. Systemic pre-treatment with C1-INH, however, failed to alter ventilation-induced complement activation with both ventilation strategies. In accordance, lung inflammation and lung injury were not affected by pre-treatment with C1-INH, neither in rats ventilated with lower tidal volumes and PEEP, nor rats ventilated with high tidal volumes without PEEP. Ventilation augments pulmonary complement activation in a rat model of S. pneumoniae pneumonia. Systemic administration of C1-INH, however, does not attenuate ventilation-induced complement activation, lung inflammation, and lung injury. PMID:24760631

  6. Spontaneously breathing anesthetized patients with a laryngeal mask airway: positive end-expiratory pressure does not improve oxygen saturation.

    PubMed

    Froessler, B; Brommundt, J; Anton, J; Khanduja, R; Kuhlen, R; Rossaint, R; Coburn, M

    2010-11-01

    Spontaneous ventilation is a popular mode of ventilation for patients with the laryngeal mask airway (LMA). Studies have shown, however, that spontaneous ventilation impairs gas exchange and that assisting or controlling ventilation results in higher oxygen saturation. Atelectasis during general anesthesia is a well described mechanism which impacts on gas exchange. Positive end-expiratory pressure (PEEP) increases the lung volume available for gas exchange. This study investigated whether the application of PEEP leads to an improvement of oxygen saturation in unassisted spontaneously breathing patients with a LMA. A total of 80 adult patients under general anesthesia were prospectively randomized into two groups. Both groups were left to breathe spontaneously. In group 1 the adjustable pressure limiting (APL) valve was opened resulting in zero end-expiratory pressure. In group 2 the valve was set to a PEEP of +7 cm H₂O. Oxygen saturation was measured by pulse oxymetry at four different phases: pre-induction, after induction and insertion of the LMA, during maintenance and in recovery. The application of PEEP did not improve oxygen saturation. In both groups the mean oxygen saturation was similar (97.2±1.8% in group 1 versus 97.2±1.9% in group 2, p=0.941) during maintenance. No effect on oxygen saturation in recovery could be found either (96.0±1.8% in group 1 versus 96.1±2.0% in group 2, p=0.952) and hemodynamics were unaffected by the application of PEEP. The application of a PEEP of +7 cm H₂O with a LMA under spontaneous ventilation cannot be recommended. Limitations of our study were the selection of healthy patients and omitting pre-oxygenation before induction which might have limited the development of atelectasis. In addition arterial partial pressure of oxygen (p(a)O₂) measurements could have revealed subtle changes in oxygenation.

  7. 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

  8. [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

  9. How ARDS should be treated.

    PubMed

    Gattinoni, Luciano; Quintel, Michael

    2016-04-06

    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.

  10. 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.

  11. 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…

  12. 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…

  13. 21 CFR 868.5965 - Positive end expiratory pressure breathing attachment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... attachment. 868.5965 Section 868.5965 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... Positive end expiratory pressure breathing attachment. (a) Identification. A positive end expiratory pressure (PEEP) breathing attachment is a device attached to a ventilator that is used to elevate...

  14. Identifying environmental health priorities for a whole nation: the use of principal environmental exposure pathways in the Philippines.

    PubMed

    Hertzman, C; Torres, E; Subida, R; Martins, J

    1998-01-01

    This paper presents a novel approach to establishing environmental health priorities for a large society, based upon the concept of principal environmental exposure pathways (PEEPs). Principal environmental exposure pathways extend the concept of a causal pathway backward from health outcome to exposure, then to the industrial, transportation, commercial, or living conditions that gave rise to the pollution of interest. In the Philippines, where the method was developed and used, five PEEPs were identified: an urban air-pollution pathway; a community water-supply pathway; an urban solid-waste pathway; a rural "point-source" pathway; and a pathway whereby fertilizers and pesticides affect food, worker health, and rural water supplies. Characterizing the PEEPs involved pinpointing the populations at risk necessary to estimate the burden of morbidity and mortality related to each as well as identifying the health outcomes that were experienced by those exposed along each pathway or that they could be expected to experience; determining where adequate health-outcome information was available or absent; where exposure sources were or were not adequately identified; where there were significant gaps in agency responsibilities; where new data flows were needed; and where things could have been improved by improving inter-agency cooperation. The most important success of the PEEP method was to reduce the "problem of everything" in a complex country of 65 million people to a small and manageable number of priority environmental exposures.

  15. 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.

  16. 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

  17. 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

  18. High-inflation pressure and positive end-expiratory pressure. Injurious to the lung? No.

    PubMed

    Nelson, L D

    1996-07-01

    Survival rates in ARDS with conventional ventilation using high oxygen fractions and low PEEP levels have been reported to be less than 10%. In three prospective evaluations of ARDS in the 1980s, mortality rates remained greater than 60%. Early studies using high-level PEEP therapy in severe ARDS by Douglas, Downs, Kirby, and Civetta showed improved survival rates with ranges between 60% and 80%. In 1979 Gallagher reviewed 59 patients with ARDS who were treated with PEEP greater than 15 cm H2O titrated to improve FRC by achieving an intrapulmonary shunt fraction of 15%. The overall survival was 65%, with only 5% of the patients dying secondary to respiratory failure. In the more recent study by Miller in trauma patients and later by DiRusso in a variety of surgical patients, the overall mortality rate for those patients receiving PEEP greater than 15 cm H2O was 20% to 30%. Of the 14 patients who died, only seven (10% of the total) succumbed to respiratory failure. The remaining patients died from the primary underlying disease with normal oxygenation or after significant weaning from high PEEP levels. By using a goal-oriented approach to the management of patients with severe ARDS, we have found that high-level PEEP therapy was effective in lowering the intrapulmonary shunt and improving the SaO2 at acceptable levels of inspired oxygen. All of these patients were ventilated with traditional high tidal volumes (10 to 15 mL/kg) and therefore exhibited high peak inspiratory airway pressures. This support method did not seem to cause lung injury or an excessive amount of barotrauma in these patients, but in fact, was associated with a lower mortality rate (30%) than reported in other studies of patients with lesser degrees of lung oxygenation dysfunction and extrapulmonary organ system dysfunction. Currently available information indicates that increases in mean airway pressure (induced with PEEP or other modes of ventilatory support to restore losses in FRC that occur

  19. New parachute cuff and positive end-expiratory pressure to minimize tracheal injury and prevent aspiration.

    PubMed

    Nordin, U; Lyttkens, L

    1979-01-01

    A new parachute cuff has been tested in combination with a positive end-expiratory pressure (PEEP) on mongrel dogs. During positive-pressure ventilation the intracuff and intratracheal pressures showed synchronous, identical pressure variations, and therefore theoretically with this type of cuff the pressure against the tracheal wall would be minimal. The cuff provided a seal against gas leakage from the lungs throughout the entire test period, i.e., for up to 7 h. To avoid aspiration of mouth contents during the passive exhalation phase, different amounts of PEEP were tested. A PEEP of 4.0--8.0 cm H2O always produced a seal against a column of fluid in the mouth exerting a hydrostatic pressure of 5.4--8.8 cm H2O against the cuff. This seal was maintained during the whole test period. No difference in sealing capacity was found when the cuff was used with a normal respiratory frequency (20/min) and with high-frequency positive-pressure ventilation (60/min). When the PEEP is eliminated, e.g., when the respirator is disconnected for suction of the endotracheal tube, the sealing effect will be abolished. As the cuff extends up into the larynx there will be no pooling of fluid above the cuff. The risk of aspiration can therefore be diminished by suction of oral cavity before disconnecting the respirator. With the use of the pneumatic valve principle together with high-frequency positive-pressure ventilation, an open respirator system can produce a continuous PEEP, thereby preventing aspiration even during suctioning of the tracheal tube.

  20. 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

  1. 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

  2. Near-fatal misuse of medical tape around an endotracheal tube connector during inhalation anesthesia in a horse

    PubMed Central

    Gregson, Rachael; Clutton, R. Eddie

    2012-01-01

    A 7-year-old gelded Irish sports horse weighing 650 kg was anesthetized on 2 consecutive days for lavage of a septic right radio-carpal joint. On both occasions the endotracheal tube connector, which had been bound in medical tape to produce an airtight seal, functioned as a unidirectional valve during mechanical ventilation, retarding expiration, imposing positive end expiratory pressure (PEEP), and probably continuous positive airway pressure (CPAP). The equipment dysfunction was not identified on either occasion despite close inspection prompted by progressive increases in airway pressure and thoracic distension. Whilst the PEEP and CPAP exerted unexpectedly modest cardiovascular effects and the horse recovered uneventfully on both occasions, the improvisation may have proven fatal in a higher-risk subject. PMID:23450862

  3. Shorebird use of managed wetlands in the Mississippi Alluvial Valley

    USGS Publications Warehouse

    Twedt, D.J.; Nelms, C.O.; Rettig, V.E.; Aycock, S.R.

    1998-01-01

    We assessed shorebird densities on managed wetland habitats during fall and winter within the primarily agricultural landscape of the Mississippi Alluvial Valley. From November through March, shorebird densities were greater on soybean fields than on rice or moist-soil fields. Killdeer (Charadrius vociferus) and Common Snipe (Gallinago gallinago) were common throughout winter, whereas Yellowlegs (Tringa spp.) and ?peep? sandpipers (Calidris spp.) were present but less abundant. During fall, Dowitchers (Limnodromus spp.), Pectoral Sandpipers (Calidris melanotos), Killdeer, and peep sandpipers were the most abundant species on managed shorebird habitat units. Although shorebird densities were consistently greater on habitats managed by drawing down existing water, we were unable to detect a significant difference in densities from areas managed by flooding previously dry habitat.

  4. 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.

  5. Early phonological development: creating an assessment test.

    PubMed

    Stoel-Gammon, Carol; Williams, A Lynn

    2013-04-01

    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 acquisition, based on lexical norms from the MacArthur-Bates Communicative Developmental Inventories, served as the primary criterion for creating a word list. Phonetic and semantic properties of the words were also considered in selecting items for the test. Productions of words using the PEEPS protocol have been gathered from a group of children with typical development and another group with cleft lip and/or palate. By 24 months of age, the children with typical development produced more than 90% of the target words and the children with atypical development produced 73% of the words. Regarding administration, the time needed for administering the protocol decreased with age.

  6. 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

  7. A Brief Review of the Adult Respiratory Distress Syndrome

    PubMed Central

    Hassan, Sheik N.; Hackney, Robert L.

    1982-01-01

    The adult respiratory distress syndrome (ARDS) is seen with increasing frequency. It is associated with a variety of conditions even in the absence of preexisting pulmonary diseases. The treatment often includes intubation, using positive-end expiratory pressure (PEEP), and other ancillary support. The mortality rate is high, and physicians caring for such patients should be on guard for disseminated intravascular coagulation, gastrointestinal hemorrhage, and infection. PMID:7120452

  8. Dependence of lung injury on inflation rate during low-volume ventilation in normal open-chest rabbits.

    PubMed

    D'Angelo, Edgardo; Pecchiari, Matteo; Saetta, Marina; Balestro, Elisabetta; Milic-Emili, Joseph

    2004-07-01

    Lung mechanics and morphometry were assessed in two groups of nine normal open-chest rabbits mechanically ventilated (MV) for 3-4 h at zero end-expiratory pressure (ZEEP) with physiological tidal volumes (Vt; 11 ml/kg) and high (group A) or low (group B) inflation flow (44 and 6.1 ml x kg(-1) x s(-1), respectively). Relative to initial MV on positive end-expiratory pressure (PEEP; 2.3 cmH(2)O), MV on ZEEP increased quasi-static elastance and airway and viscoelastic resistance more in group A (+251, +393, and +225%, respectively) than in group B (+180, +247, and +183%, respectively), with no change in viscoelastic time constant. After restoration of PEEP, quasi-static elastance and viscoelastic resistance returned to control, whereas airway resistance, still relative to initial values, remained elevated more in group A (+86%) than in group B (+33%). In contrast, prolonged high-flow MV on PEEP had no effect on lung mechanics of seven open-chest rabbits (group C). Gas exchange on PEEP was equally preserved in all groups, and the lung wet-to-dry ratios were normal. Relative to group C, both groups A and B had an increased percentage of abnormal alveolar-bronchiolar attachments and number of polymorphonuclear leukocytes in alveolar septa, the latter being significantly larger in group A than in group B. Thus prolonged MV on ZEEP with cyclic opening-closing of peripheral airways causes alveolar-bronchiolar uncoupling and parenchymal inflammation with concurrent, persistent increase in airway resistance, which are worsened by high-inflation flow.

  9. Continuum and molecular-dynamics simulation of nanodroplet collisions.

    PubMed

    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 (Kn_{gas}=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 (Kn_{liquid}=0.01 for D=36nm) 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

  10. 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

  11. Different effects of surfactant proteins B and C - implications for development of synthetic surfactants.

    PubMed

    Curstedt, Tore; Johansson, Jan

    2010-06-01

    Treatment of premature newborn rabbits with synthetic surfactants containing a surfactant protein C analogue in a simple phospholipid mixture gives similar tidal volumes as treatment with poractant alfa (Curosurf(R)) but ventilation with a positive end-expiratory pressure (PEEP) is needed for this synthetic surfactant to stabilize the alveoli at end-expiration. The effect on lung gas volumes seems to depend on the structure of the peptide since treatment with a synthetic surfactant containing the 21-residue peptide (LysLeu(4))(4)Lys (KL(4)) gives low lung gas volumes in experiments also performed with PEEP. Surfactant preparations containing both surfactant proteins B and C or their analogues prevent alveolar collapse at end-expiration even if ventilated without PEEP. Treatment of premature newborn rabbits with different natural surfactants indicates that both the lipid composition and the proteins are important in order to stabilize the alveoli at end-expiration. Synthetic surfactants containing two peptides may be able to replace natural surfactants within the near future but more trials need to be performed before any conclusion can be drawn about the ideal composition of this new generation of synthetic surfactants.

  12. Effect of positive end-expiratory pressure on acoustic wave propagation in experimental porcine lung injury.

    PubMed

    Räsänen, Jukka; Nemergut, Michael E; Gavriely, Noam

    2015-03-01

    To evaluate the effect of positive end-expiratory pressure (PEEP) on sound propagation through injured lungs, we injected a multifrequency broad-band sound signal into the airway of eight anesthetized, intubated and mechanically ventilated pigs, while recording transmitted sound at three locations bilaterally on the chest wall. Oleic acid injections effected a severe pulmonary oedema predominately in the dependent lung regions, with an average increase in venous admixture from 19 ± 15 to 59 ± 14% (P < 0.001), and a reduction in dynamic respiratory system compliance from 34 ± 7 to 14 ± 4 ml cmH2 O(-1) (P < 0.001). A concomitant decrease in sound transit time was seen in the dependent lung regions (P < 0.05); no statistically significant change occurred in the lateral or non-dependent areas. The application of PEEP resulted in a decrease in venous admixture, increase in respiratory system compliance and return of the sound transit time to pre-injury levels in the dependent lung regions. Our results indicate that sound transmission velocity increases in lung tissue affected by permeability-type pulmonary oedema in a manner reversible during alveolar recruitment with PEEP.

  13. Recruitment maneuvers in acute respiratory distress syndrome: The safe way is the best way.

    PubMed

    Santos, Raquel S; Silva, Pedro L; Pelosi, Paolo; Rocco, Patricia Rm

    2015-11-01

    Acute respiratory distress syndrome (ARDS) represents a serious problem in critically ill patients and is associated with in-hospital mortality rates of 33%-52%. Recruitment maneuvers (RMs) are a simple, low-cost, feasible intervention that can be performed at the bedside in patients with ARDS. RMs are characterized by the application of airway pressure to increase transpulmonary pressure transiently. Once non-aerated lung units are reopened, improvements are observed in respiratory system mechanics, alveolar reaeration on computed tomography, and improvements in gas exchange (functional recruitment). However, the reopening process could lead to vascular compression, which can be associated with overinflation, and gas exchange may not improve as expected (anatomical recruitment). The purpose of this review was to discuss the effects of different RM strategies - sustained inflation, intermittent sighs, and stepwise increases of positive end-expiratory pressure (PEEP) and/or airway inspiratory pressure - on the following parameters: hemodynamics, oxygenation, barotrauma episodes, and lung recruitability through physiological variables and imaging techniques. RMs and PEEP titration are interdependent events for the success of ventilatory management. PEEP should be adjusted on the basis of respiratory system mechanics and oxygenation. Recent systematic reviews and meta-analyses suggest that RMs are associated with lower mortality in patients with ARDS. However, the optimal RM method (i.e., that providing the best balance of benefit and harm) and the effects of RMs on clinical outcome are still under discussion, and further evidence is needed.

  14. 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.

  15. 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

  16. [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

  17. 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.

  18. 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.

  19. 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.

  20. Airway and tissue mechanics in ventilated patients with pneumonia.

    PubMed

    Lorx, András; Suki, Béla; Hercsuth, Magdolna; Szabó, Barna; Pénzes, István; Boda, Krisztina; Hantos, Zoltán

    2010-04-30

    We applied the low-frequency forced oscillation technique (LFOT) to measure respiratory impedance (Zrs) at various positive end-expiratory pressures (PEEPs) in 14 sedated and intubated patients with pneumonia classified into a mild (Group 1) and a severe group (Group 2) based on lung injury scores. The Zrs spectra were fit with the constant-phase (CP) model including Newtonian resistance (R(N)) and tissue damping (G) and elastance (H), a distributed airway resistance (DR) and a distributed tissue elastance (DH) model. Using the CP model, all parameters revealed a negative PEEP dependence (p<0.001) in Group 2 and H was higher in Group 2 (p=0.014). The variability of H from the DH model was nearly significantly larger in Group 1 (p=0.061). Following bronchodilator inhalation, G significantly decreased (p=0.009). Thus, the CP model provides a robust partitioning of Zrs into tissue properties and R(N), a surrogate for airway resistance, while the distributed models suggest that lung heterogeneity decreases with increasing PEEP.

  1. Low-frequency assessment of airway and tissue mechanics in ventilated COPD patients.

    PubMed

    Lorx, András; Szabó, Barna; Hercsuth, Magdolna; Pénzes, István; Hantos, Zoltán

    2009-12-01

    Low-frequency forced oscillations have increasingly been employed to characterize airway and tissue mechanics separately in the normal respiratory system and animal models of lung disease; however, few data are available on the use of this method in chronic obstructive pulmonary disease (COPD). We studied 30 intubated and mechanically ventilated patients (COPD, n = 9; acute exacerbation of COPD, n = 21) during short apneic intervals at different levels of positive end-expiratory pressure (PEEP), with small-amplitude forced oscillations between 0.4 and 4.8 Hz. In 16 patients, measurements were made before and after inhalation of fenoterol hydrobromide plus ipratropium bromide (Berodual). Newtonian resistance and coefficients of tissue resistance (G) and elastance (H) were estimated from the respiratory system impedance (Zrs) data by model fitting. Apart from some extremely high Zrs data obtained primarily at relatively low PEEP levels, the model yielded a reasonable partitioning of the airway and tissue parameters, and the inclusion of further parameters did not improve the model performance. With increasing PEEP, Newtonian resistance and the ratio G/H decreased, reflecting the volume dependence of the airway caliber and the improved homogeneity of the lungs, respectively. Bronchodilation after the administration of Berodual was also associated with simultaneous decreases in G and H, indicating recruitment of lung units. In conclusion, the measurement of low-frequency Zrs can be accomplished in ventilated COPD patients during short apneic periods and offers valuable information on the mechanical status of the airways and tissues.

  2. 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.

  3. Mechanical ventilation in abdominal surgery.

    PubMed

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

    2014-01-01

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

  4. 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

    2016-03-02

    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.

  5. 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.

  6. Predicting others' actions via grasp and gaze: evidence for distinct brain networks.

    PubMed

    Ramsey, Richard; Cross, Emily S; Hamilton, Antonia F de C

    2012-07-01

    During social interactions, how do we predict what other people are going to do next? One view is that we use our own motor experience to simulate and predict other people's actions. For example, when we see Sally look at a coffee cup or grasp a hammer, our own motor system provides a signal that anticipates her next action. Previous research has typically examined such gaze and grasp-based simulation processes separately, and it is not known whether similar cognitive and brain systems underpin the perception of object-directed gaze and grasp. Here we use functional magnetic resonance imaging to examine to what extent gaze- and grasp-perception rely on common or distinct brain networks. Using a 'peeping window' protocol, we controlled what an observed actor could see and grasp. The actor could peep through one window to see if an object was present and reach through a different window to grasp the object. However, the actor could not peep and grasp at the same time. We compared gaze and grasp conditions where an object was present with matched conditions where the object was absent. When participants observed another person gaze at an object, left anterior inferior parietal lobule (aIPL) and parietal operculum showed a greater response than when the object was absent. In contrast, when participants observed the actor grasp an object, premotor, posterior parietal, fusiform and middle occipital brain regions showed a greater response than when the object was absent. These results point towards a division in the neural substrates for different types of motor simulation. We suggest that left aIPL and parietal operculum are involved in a predictive process that signals a future hand interaction with an object based on another person's eye gaze, whereas a broader set of brain areas, including parts of the action observation network, are engaged during observation of an ongoing object-directed hand action.

  7. 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

  8. 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

  9. 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

  10. 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

  11. Particle size concentration distribution and influences on exhaled breath particles in mechanically ventilated patients.

    PubMed

    Wan, Gwo-Hwa; Wu, Chieh-Liang; 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.

  12. Implementation of a minimal set of biological tests to assess the ecotoxic effects of effluents from land-based marine fish farms.

    PubMed

    Carballeira, C; De Orte, M R; Viana, I G; Carballeira, A

    2012-04-01

    Environmental monitoring plans (EMP) that include chemical analysis of water, a battery of bioassays and the study of local hydrodynamic conditions are required for land-based marine aquaculture. In this study, the following standardized toxicity tests were performed to assess the toxicity of effluents from eight land-base marine fish farms (LBMFFs) located on the northwest coast of Spain: bacterial bioluminescence (with Vibrio fischeri at 15 and 30 min), microalgal growth (with Phaeodactyllum tricornutum and Isochrysis galbana) and sea urchin larval development (with Paracentrotus lividus and Arbacia lixula). These bioassays were evaluated for inclusion in routine fish farm monitoring. Effective concentrations (EC(5), EC(10), EC(20), EC(50)) for each bioassay were calculated from dose-response curves, obtained by fitting the bioassay results to the best parametric model. Moreover, a graphical method of integrating the results from the battery of bioassays and classifying the toxicity was proposed, and the potential ecotoxic effects probe (PEEP) index was calculated. The bacterial bioluminiscence test at 30min, growth of I. galbana and larval development of A. lixula were found to be the most sensitive and useful tests. Graphical integration of these test results enabled definition of the ecotoxicological profiles of the different farms. The PEEP index, considering EC(20), efficiently reflected the toxic loading potential of LBMFF effluents. In conclusion, a battery of bioassays with species from different low trophic levels is recommended as a rapid and cost-effective methodology for assessing LBMFF discharges. The graphical integration method and the PEEP index are proposed for consideration in EMPs for such farms.

  13. Treatment of Acute Low Pressure Pulmonary Edema in Dogs

    PubMed Central

    Prewitt, R. M.; McCarthy, J.; Wood, L. D. H.

    1981-01-01

    Severe pulmonary edema sometimes develops despite normal pulmonary capillary wedge pressure (Ppw). The equation describing net transvascular flux of lung liquid predicts decreased edema when hydrostatic pressure is reduced or when colloid osmotic pressure is increased in the pulmonary vessels. We tested these predictions in a model of pulmonary capillary leak produced in 35 dogs by intravenous oleic acid. 1 h later, the dogs were divided into five equal groups and treated for 4 h in different ways: (a) not treated, to serve as the control group (Ppw = 11.1 mm Hg); (b) given albumin to increase colloid osmotic pressure by 5 mm Hg (Ppw = 10.6 mm Hg); (c) ventilated with 10 cm H2O positive end-expiratory pressure (Peep) (transmural Ppw = 10.4 mm Hg); (d) phlebotomized to reduce Ppw to 6 mm Hg; (e) infused with nitroprusside, which also reduced Ppw to 6 mm Hg. Phlebotomy and nitroprusside reduced the edema in excised lungs by 50% (P< 0.001), but Peep and albumin did not affect the edema. Pulmonary shunt decreased on Peep and increased on nitroprusside, and lung compliance was not different among the treatment groups, demonstrating that these variables are poor indicators of changes in edema. Cardiac output decreased during the treatment period in all but the nitroprusside group, where Ppw decreased and cardiac output did not. We conclude that canine oleic acid pulmonary edema is reduced by small reductions in hydrostatic pressure, but not by increased colloid osmotic pressure, because the vascular permeability to liquid and protein is increased. These results suggest that low pressure pulmonary edema may be reduced by seeking the lowest Ppw consistent with adequate cardiac output enhanced by vasoactive agents like nitroprusside. Further, colloid infusions and Peep are not helpful in reducing edema, so they may be used in the lowest amount that provides adequate circulating volume and arterial O2 saturation on nontoxic inspired O2. Until these therapeutic principles

  14. 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

  15. 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

  16. Influence of respiratory rate and end-expiratory pressure variation on cyclic alveolar recruitment in an experimental lung injury model

    PubMed Central

    2012-01-01

    Introduction Cyclic alveolar recruitment/derecruitment (R/D) is an important mechanism of ventilator-associated lung injury. In experimental models this process can be measured with high temporal resolution by detection of respiratory-dependent oscillations of the paO2 (ΔpaO2). A previous study showed that end-expiratory collapse can be prevented by an increased respiratory rate in saline-lavaged rabbits. The current study compares the effects of increased positive end-expiratory pressure (PEEP) versus an individually titrated respiratory rate (RRind) on intra-tidal amplitude of Δ paO2 and on average paO2 in saline-lavaged pigs. Methods Acute lung injury was induced by bronchoalveolar lavage in 16 anaesthetized pigs. R/D was induced and measured by a fast-responding intra-aortic probe measuring paO2. Ventilatory interventions (RRind (n = 8) versus extrinsic PEEP (n = 8)) were applied for 30 minutes to reduce Δ paO2. Haemodynamics, spirometry and Δ paO2 were monitored and the Ventilation/Perfusion distributions were assessed by multiple inert gas elimination. The main endpoints average and Δ paO2 following the interventions were analysed by Mann-Whitney-U-Test and Bonferroni's correction. The secondary parameters were tested in an explorative manner. Results Both interventions reduced Δ paO2. In the RRind group, ΔpaO2 was significantly smaller (P < 0.001). The average paO2 continuously decreased following RRind and was significantly higher in the PEEP group (P < 0.001). A sustained difference of the ventilation/perfusion distribution and shunt fractions confirms these findings. The RRind application required less vasopressor administration. Conclusions Different recruitment kinetics were found compared to previous small animal models and these differences were primarily determined by kinetics of end-expiratory collapse. In this porcine model, respiratory rate and increased PEEP were both effective in reducing the amplitude of paO2 oscillations. In contrast to

  17. 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

  18. 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.

  19. 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.

  20. Assessing the Potential Use of Eye-Tracking Triangulation for Evaluating the Usability of an Online Diabetes Exercise System.

    PubMed

    Schaarup, Clara; Hartvigsen, Gunnar; Larsen, Lars Bo; Tan, Zheng-Hua; Årsand, Eirik; Hejlesen, Ole Kristian

    2015-01-01

    The Online Diabetes Exercise System was developed to motivate people with Type 2 diabetes to do a 25 minutes low-volume high-intensity interval training program. In a previous multi-method evaluation of the system, several usability issues were identified and corrected. Despite the thorough testing, it was unclear whether all usability problems had been identified using the multi-method evaluation. Our hypothesis was that adding the eye-tracking triangulation to the multi-method evaluation would increase the accuracy and completeness when testing the usability of the system. The study design was an Eye-tracking Triangulation; conventional eye-tracking with predefined tasks followed by The Post-Experience Eye-Tracked Protocol (PEEP). Six Areas of Interests were the basis for the PEEP-session. The eye-tracking triangulation gave objective and subjective results, which are believed to be highly relevant for designing, implementing, evaluating and optimizing systems in the field of health informatics. Future work should include testing the method on a larger and more representative group of users and apply the method on different system types.

  1. Respirator management of sepsis-related respiratory failure.

    PubMed

    Chiumello, Davide; Cressoni, Massimo

    2009-09-01

    The first description of acute respiratory distress syndrome (ARDS) in adults appeared in 1967 and was characterized by dyspnea, hypoxemia, diffuse alveolar infiltrates, and reduced respiratory system compliance. ARDS and acute lung injury (ALI) syndrome have no specific treatment, only supportive care: treating the underlying cause, when possible, and using mechanical ventilation. Historically, mechanical ventilation applied normal/large tidal volumes and low levels of positive end-expiratory pressure (PEEP). Experimental data showed that a high-volume, high-pressure ventilation strategy may lead to lung lesions indistinguishable from ARDS. Subsequent randomized clinical trials showed improved survival using low tidal volumes (6 vs 12 mL/kg ideal body weight) and limiting plateau pressure to 30 cm H(2)O, although the optimal level of PEEP remains controversial. Prone positioning should be reserved for severely ill patients. Inhaled nitric oxide, which is a pulmonary vasodilator with anti-inflammatory properties, is associated with limited improvement in oxygenation without improvement in survival.

  2. Synthesis of biodegradable amphiphilic Y-shaped block co-polymers via ring-opening polymerization for drug delivery.

    PubMed

    Jia, Lin; Yan, Lifeng; Li, Yang

    2011-01-01

    A series of novel Y-shaped biodegradable block co-polymers of poly(ε-caprolactone) (PCL) and poly(ethyl ethylene phosphate) (PEEP) (PCL-(PEEP)2) were synthesized via ring-opening polymerization (ROP) of EEP with bis-hydroxy-functional ROP initiator (init-PCL-(OH)2). The init-PCL-(OH)2 was synthesized by ROP of CL using 4-hydroxybutyl acrylate (HBA) as initiator and L-tartaric acid as catalyst in bulk, and subsequently the resulting vinyl-terminated PCL was end-capped by acetyl chloride, followed by Michael addition using excess diethanolamine. The Y-shaped co-polymers and their intermediates were characterized by (1)H-, (13)C-, (31)P-NMR, FT-IR and gel-permeation chromatography. The results indicated that the molecular weight of the Y-shaped co-polymers increased with the increasing of the molar ratios of EEP to init-PCL-(OH)2 in the feed, while the PCL chain length was kept constant. The amphiphilic block co-polymers could self-assemble into micelles in aqueous solution, which was demonstrated by dynamic light scattering, (1)H-NMR and atomic force microscopy. A study of controlled release of indomethacin indicated that the amphiphilic block co-polymers could potentially provide novel vehicles for drug delivery.

  3. Effects of high tidal volume mechanical ventilation on production of cytokines, iNOS, and MIP-1β proteins in pigs.

    PubMed

    Vobruba, Václav; Klimenko, Oxana V; Kobr, Jiri; Cerna, Olga; Pokorna, Pavla; Mikula, Ivan; Hridel, Jan; Brantova, Olga; Martasek, Pavel

    2013-02-01

    The aim of this study was to investigate longitudinal changes of the pulmonary inflammatory process as a result of mechanical stress due to mechanical ventilation. The concentrations of IL-8, TNF-α, MIP-1β, nitrites/nitrates, and inducible nitric oxide synthases (iNOS) were investigated indicate in bronchoalveolar lavage (BAL). Twenty-three piglets were divided into three groups. Group I: animals breathing spontaneously; group II: mechanical ventilation (tidal volume (TV) = 7 mL/kg, PEEP = 5 cmH(2)O); group III: mechanical ventilation (TV = 15 mL/kg, PEEP = 0 cmH(2)0). Concentrations of BAL nitrites/nitrates from groups II and III increased during the first hour of mechanical ventilation (P = .03 and .02, respectively). The highest expression of iNOS was observed during the first hour in groups II and III. IL-8 concentration increased significantly in groups II and III. Production of TNF-α increased significantly in group III during the second and third hour (P = .01). Concentration of MIP-1β was significantly increased in groups II and III after the first hour (P = .012 and P = .008, respectively).

  4. 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

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. Glutamine Attenuates Acute Lung Injury Caused by Acid Aspiration

    PubMed Central

    Lai, Chih-Cheng; Liu, Wei-Lun; Chen, Chin-Ming

    2014-01-01

    Inadequate ventilator settings may cause overwhelming inflammatory responses associated with ventilator-induced lung injury (VILI) in patients with acute respiratory distress syndrome (ARDS). Here, we examined potential benefits of glutamine (GLN) on a two-hit model for VILI after acid aspiration-induced lung injury in rats. Rats were intratracheally challenged with hydrochloric acid as a first hit to induce lung inflammation, then randomly received intravenous GLN or lactated Ringer’s solution (vehicle control) thirty min before different ventilator strategies. Rats were then randomized to receive mechanical ventilation as a second hit with a high tidal volume (TV) of 15 mL/kg and zero positive end-expiratory pressure (PEEP) or a low TV of 6 mL/kg with PEEP of 5 cm H2O. We evaluated lung oxygenation, inflammation, mechanics, and histology. After ventilator use for 4 h, high TV resulted in greater lung injury physiologic and biologic indices. Compared with vehicle treated rats, GLN administration attenuated lung injury, with improved oxygenation and static compliance, and decreased respiratory elastance, lung edema, extended lung destruction (lung injury scores and lung histology), neutrophil recruitment in the lung, and cytokine production. Thus, GLN administration improved the physiologic and biologic profiles of this experimental model of VILI based on the two-hit theory. PMID:25100435

  18. The protective effects of glutamine in a rat model of ventilator-induced lung injury

    PubMed Central

    Chen, Chin-Ming; Cheng, Kuo-Chen; Li, Chien-Feng

    2014-01-01

    Background The mortality rate of patients with acute respiratory distress syndrome (ARDS) is still high despite the use of protective ventilatory strategies. We sought to examine the pharmacological effects of glutamine (GLN) in a two-hit model of endotoxin-induced inflammation followed by ventilator-induced lung injury (VILI). We hypothesized that the administration of GLN ameliorates the VILI. Methods Sprague-Dawley rats were anesthetized and given lipopolysaccharide (LPS) intratracheally as a first hit to induce lung inflammation, followed 24 h later by a second hit of mechanical ventilation (MV) with either low tidal volume (6 mL/kg) with 5 cmH2O of positive end-expiratory pressure (PEEP) or high tidal volume (22 mL/kg) with zero PEEP for 4 h. GLN or lactated Ringer’s solution as the placebo was administered intravenously 15 min prior to MV. Results In the LPS-challenged rats ventilated with high tidal volume, the treatment with GLN improved lung injury indices, lung mechanics and cytokine responses compared with the placebo group. Conclusions The administration of GLN given immediately prior to MV may be beneficial in the context of reducing VILI. PMID:25589963

  19. [The basics on mechanical ventilation support in acute respiratory distress syndrome].

    PubMed

    Tomicic, V; Fuentealba, A; Martínez, E; Graf, J; Batista Borges, J

    2010-01-01

    Acute Respiratory Distress Syndrome (ARDS) is understood as an inflammation-induced disruption of the alveolar endothelial-epithelial barrier that results in increased permeability and surfactant dysfunction followed by alveolar flooding and collapse. ARDS management relies on mechanical ventilation. The current challenge is to determine the optimal ventilatory strategies that minimize ventilator-induced lung injury (VILI) while providing a reasonable gas exchange. The data support that a tidal volume between 6-8 ml/kg of predicted body weight providing a plateau pressure < 30 cmH₂O should be used. High positive end expiratory pressure (PEEP) has not reduced mortality, nevertheless secondary endpoints are improved. The rationale used for high PEEP argues that it prevents cyclic opening and closing of airspaces, probably the major culprit of development of VILI. Chest computed tomography has contributed to our understanding of anatomic-functional distribution patterns in ARDS. Electric impedance tomography is a technique that is radiation-free, but still under development, that allows dynamic monitoring of ventilation distribution at bedside.

  20. 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.

  1. Assessing the Potential Use of Eye-Tracking Triangulation for Evaluating the Usability of an Online Diabetes Exercise System.

    PubMed

    Schaarup, Clara; Hartvigsen, Gunnar; Larsen, Lars Bo; Tan, Zheng-Hua; Årsand, Eirik; Hejlesen, Ole Kristian

    2015-01-01

    The Online Diabetes Exercise System was developed to motivate people with Type 2 diabetes to do a 25 minutes low-volume high-intensity interval training program. In a previous multi-method evaluation of the system, several usability issues were identified and corrected. Despite the thorough testing, it was unclear whether all usability problems had been identified using the multi-method evaluation. Our hypothesis was that adding the eye-tracking triangulation to the multi-method evaluation would increase the accuracy and completeness when testing the usability of the system. The study design was an Eye-tracking Triangulation; conventional eye-tracking with predefined tasks followed by The Post-Experience Eye-Tracked Protocol (PEEP). Six Areas of Interests were the basis for the PEEP-session. The eye-tracking triangulation gave objective and subjective results, which are believed to be highly relevant for designing, implementing, evaluating and optimizing systems in the field of health informatics. Future work should include testing the method on a larger and more representative group of users and apply the method on different system types. PMID:26262015

  2. Pulmonary hyperinflation. A form of barotrauma during mechanical ventilation.

    PubMed

    Baeza, O R; Wagner, R B; Lowery, B D

    1975-11-01

    Barotrauma has been used to describe several specific complications related to mechanical ventilation. These include tension lung cyst, pneumothorax, pneumomediastinum, pneumoperitoneum, and subcutaneous emphysema. Pulmonary hyperinflation, another such complication, occurred in 6 patients, being fatal in 3. Two pathophysiologic mechanisms are discussed. The simpler, and well-recognized, ball-valve airway obstruction allows inspiration of air delivered by the mechanical ventilator but prevents expiration. A more complex circumstance exists when pulmonary contusion or infiltration produces differential lung compliances. This allows extreme hyperinflation of areas of normal lung during attempts to ventilate abnormal lung of low compliance. This mechanism is particularly evident when positive end-expiratory pressure (PEEP) is used in an attempt to open collapsed ventilatory units. Functional complications of lung hyperinflation include decreased alveolar ventilation and compression effects on adjacent structures. Interference with and shifts of regional lung perfusion may worsen gas exchange. Proper treatment includes airway clearance by bronchoscopy, the judicious use of bronchodilators, the discontinuance of PEEP, and adjustments of mechanical ventilators to prevent high airway pressures.

  3. Transpulmonary pressure monitoring during mechanical ventilation: a bench-to-bedside review.

    PubMed

    Mietto, Cristina; Malbrain, Manu L N G; Chiumello, Davide

    2015-01-01

    Different ventilation strategies have been suggested in the past in patients with acute respiratory distress syndrome (ARDS). Airway pressure monitoring alone is inadequate to assure optimal ventilatory support in ARDS patients. The assessment of transpulmonary pressure (PTP) can help clinicians to tailor mechanical ventilation to the individual patient needs. Transpulmonary pressure monitoring, defined as airway pressure (Paw) minus intrathoracic pressure (ITP), provides essential information about chest wall mechanics and its effects on the respiratory system and lung mechanics. The positioning of an esophageal catheter is required to measure the esophageal pressure (Peso), which is clinically used as a surrogate for ITP or pleural pressure (Ppl), and calculates the transpulmonary pressure. The benefits of such a ventilation approach are avoiding excessive lung stress and individualizing the positive end-expiratory pressure (PEEP) setting. The aim is to prevent over-distention of alveoli and the cyclic recruitment/derecruitment or shear stress of lung parenchyma, mechanisms associated with ventilator-induced lung injury (VILI). Knowledge of the real lung distending pressure, i.e. the transpulmonary pressure, has shown to be useful in both controlled and assisted mechanical ventilation. In the latter ventilator modes, Peso measurement allows one to assess a patient's respiratory effort, patient-ventilator asynchrony, intrinsic PEEP and the calculation of work of breathing. Conditions that have an impact on Peso, such as abdominal hypertension, will also be discussed briefly.

  4. Transpulmonary pressure monitoring during mechanical ventilation: a bench-to-bedside review.

    PubMed

    Mietto, Cristina; Malbrain, Manu L N G; Chiumello, Davide

    2015-01-01

    Different ventilation strategies have been suggested in the past in patients with acute respiratory distress syndrome (ARDS). Airway pressure monitoring alone is inadequate to assure optimal ventilatory support in ARDS patients. The assessment of transpulmonary pressure (PTP) can help clinicians to tailor mechanical ventilation to the individual patient needs. Transpulmonary pressure monitoring, defined as airway pressure (Paw) minus intrathoracic pressure (ITP), provides essential information about chest wall mechanics and its effects on the respiratory system and lung mechanics. The positioning of an esophageal catheter is required to measure the esophageal pressure (Peso), which is clinically used as a surrogate for ITP or pleural pressure (Ppl), and calculates the transpulmonary pressure. The benefits of such a ventilation approach are avoiding excessive lung stress and individualizing the positive end-expiratory pressure (PEEP) setting. The aim is to prevent over-distention of alveoli and the cyclic recruitment/derecruitment or shear stress of lung parenchyma, mechanisms associated with ventilator-induced lung injury (VILI). Knowledge of the real lung distending pressure, i.e. the transpulmonary pressure, has shown to be useful in both controlled and assisted mechanical ventilation. In the latter ventilator modes, Peso measurement allows one to assess a patient's respiratory effort, patient-ventilator asynchrony, intrinsic PEEP and the calculation of work of breathing. Conditions that have an impact on Peso, such as abdominal hypertension, will also be discussed briefly. PMID:26575165

  5. 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

  6. Effect of regional lung inflation on ventilation heterogeneity at different length scales during mechanical ventilation of normal sheep lungs.

    PubMed

    Wellman, Tyler J; Winkler, Tilo; Costa, Eduardo L V; Musch, Guido; Harris, R Scott; Venegas, Jose G; Vidal Melo, Marcos F

    2012-09-01

    Heterogeneous, small-airway diameters and alveolar derecruitment in poorly aerated regions of normal lungs could produce ventilation heterogeneity at those anatomic levels. We modeled the washout kinetics of (13)NN with positron emission tomography to examine how specific ventilation (sV) heterogeneity at different length scales is influenced by lung aeration. Three groups of anesthetized, supine sheep were studied: high tidal volume (Vt; 18.4 ± 4.2 ml/kg) and zero end-expiratory pressure (ZEEP) (n = 6); low Vt (9.2 ± 1.0 ml/kg) and ZEEP (n = 6); and low Vt (8.2 ± 0.2 ml/kg) and positive end-expiratory pressure (PEEP; 19 ± 1 cmH(2)O) (n = 4). We quantified fractional gas content with transmission scans, and sV with emission scans of infused (13)NN-saline. Voxel (13)NN-washout curves were fit with one- or two-compartment models to estimate sV. Total heterogeneity, measured as SD[log(10)(sV)], was divided into length-scale ranges by measuring changes in variance of log(10)(sV), resulting from progressive filtering of sV images. High-Vt ZEEP showed higher sV heterogeneity at <12- (P < 0.01), 12- to 36- (P < 0.01), and 36- to 60-mm (P < 0.05) length scales compared with low-Vt PEEP, with low-Vt ZEEP in between. Increased heterogeneity was associated with the emergence of low sV units in poorly aerated regions, with a high correlation (r = 0.95, P < 0.001) between total heterogeneity and the fraction of lung with slow washout. Regional mean fractional gas content was inversely correlated with regional sV heterogeneity at <12- (r = -0.67), 12- to 36- (r = -0.74), and >36-mm (r = -0.72) length scales (P < 0.001). We conclude that sV heterogeneity at length scales <60 mm increases in poorly aerated regions of mechanically ventilated normal lungs, likely due to heterogeneous small-airway narrowing and alveolar derecruitment. PEEP reduces sV heterogeneity by maintaining lung expansion and airway patency at those small length scales.

  7. 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

  8. 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

  9. Continuous positive airway pressure and ventilation are more effective with a nasal mask than a full face mask in unconscious subjects: a randomized controlled trial

    PubMed Central

    2013-01-01

    Introduction Upper airway obstruction (UAO) is a major problem in unconscious subjects, making full face mask ventilation difficult. The mechanism of UAO in unconscious subjects shares many similarities with that of obstructive sleep apnea (OSA), especially the hypotonic upper airway seen during rapid eye movement sleep. Continuous positive airway pressure (CPAP) via nasal mask is more effective at maintaining airway patency than a full face mask in patients with OSA. We hypothesized that CPAP via nasal mask and ventilation (nCPAP) would be more effective than full face mask CPAP and ventilation (FmCPAP) for unconscious subjects, and we tested our hypothesis during induction of general anesthesia for elective surgery. Methods In total, 73 adult subjects requiring general anesthesia were randomly assigned to one of four groups: nCPAP P0, nCPAP P5, FmCPAP P0, and FmCPAP P5, where P0 and P5 represent positive end-expiratory pressure (PEEP) 0 and 5 cm H2O applied prior to induction. After apnea, ventilation was initiated with pressure control ventilation at a peak inspiratory pressure over PEEP (PIP/PEEP) of 20/0, then 20/5, and finally 20/10 cm H2O, each applied for 1 min. At each pressure setting, expired tidal volume (Vte) was calculated by using a plethysmograph device. Results The rate of effective tidal volume (Vte > estimated anatomical dead space) was higher (87.9% vs. 21.9%; P<0.01) and the median Vte was larger (6.9 vs. 0 mL/kg; P<0.01) with nCPAP than with FmCPAP. Application of CPAP prior to induction of general anesthesia did not affect Vte in either approach (nCPAP pre- vs. post-; 7.9 vs. 5.8 mL/kg, P = 0.07) (FmCPAP pre- vs. post-; 0 vs. 0 mL/kg, P = 0.11). Conclusions nCPAP produced more effective tidal volume than FmCPAP in unconscious subjects. Trial registration ClinicalTrials.gov identifier: NCT01524614. PMID:24365207

  10. Maintaining end-expiratory transpulmonary pressure prevents worsening of ventilator-induced lung injury caused by chest wall constriction in surfactant-depleted rats

    PubMed Central

    Loring, Stephen H.; Pecchiari, Matteo; Valle, Patrizia Della; Monaco, Ario; Gentile, Guendalina; D'Angelo, Edgardo

    2014-01-01

    Objective To see whether in acute lung injury (ALI) 1) compression of the lungs caused by thoracoabdominal constriction degrades lung function and worsens ventilator-induced lung injury (VILI), and 2) maintaining end-expiratory transpulmonary pressure (Pl) by increasing positive end-expiratory pressure (PEEP) reduces the deleterious effects of chest wall constriction. Design Experimental study in rats. Setting Physiology laboratory. Interventions ALI was induced in 3 groups of 9 rats by saline lavage. Nine animals immediately sacrificed served as control group. Group L had lavage only, group LC had the chest wall constricted with an elastic binder, and group LCP had the same chest constriction but with PEEP raised to maintain end-expiratory Pl. After lavage, all groups were ventilated with the same pattern for 1½ hr. Measurements and Main Results Pl, measured with an esophageal balloon-catheter, lung volume changes, arterial blood gasses and pH were assessed during mechanical ventilation (MV). Lung wet-to-dry ratio (W/D), albumin, TNF-α, IL-1β, IL-6, IL-10, and MIP-2 in serum and bronchoalveolar lavage fluid (BALF), and serum E-selectin and von Willebrand Factor (vWF) were measured at the end of MV. Lavage caused hypoxemia and acidemia, increased lung resistance and elastance, and decreased end-expiratory lung volume. With prolonged MV, lung mechanics, hypoxemia, and W/D were significantly worse in group LC. Pro-inflammatory cytokines except E-selectin were elevated in serum and BALF in all groups, with significantly greater levels of TNF-α, IL-1β, and IL-6 in group LC, which also exhibited significantly worse bronchiolar injury and greater heterogeneity of airspace expansion at a fixed Pl than other groups. Conclusions Chest wall constriction in ALI reduces lung volume, worsens hypoxemia, and increases pulmonary edema, mechanical abnormalities, pro-inflammatory mediator release, and histological signs of VILI. Maintaining end-expiratory Pl at preconstriction

  11. 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.

  12. Science and evidence: separating fact from fiction.

    PubMed

    Hess, Dean R

    2013-10-01

    Evidence-based medicine (EBM) is the integration of individual clinical expertise with the best available research evidence from systematic research and the patient's values and expectations. A hierarchy of evidence can be used to assess the strength upon which clinical decisions are made. The efficient approach to finding the best evidence is to identify systematic reviews or evidence-based clinical practice guidelines. Respiratory therapies that evidence supports include noninvasive ventilation for appropriately selected patients, lung-protective ventilation, and ventilator discontinuation protocols. Evidence does not support use of weaning parameters, albuterol for ARDS, and high frequency oscillatory ventilation for adults. Therapy with equivocal evidence includes airway clearance, selection of an aerosol delivery device, and PEEP for ARDS. Although all tenets of EBM are not universally accepted, the principles of EBM nonetheless provide a valuable approach to respiratory care practice.

  13. 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

  14. Development of a bronchospasm device model.

    PubMed

    Sugiura, Asumi; Kawamae, Kaneyuki

    2015-02-01

    There is no strong evidence to support ventilatory management for critical limitation of expiratory flow, such as bronchospasm during anesthesia or an acute exacerbation of severe asthma and chronic obstructive pulmonary disease (COPD). Animal models cannot be used to develop reproducible experimental models for conducting mechanical ventilation strategy research relating to these etiologies due to the resulting respiratory and hemodynamic instabilities. Therefore, we developed a device model by modifying a positive end-expiratory pressure (PEEP) valve that can simulate the characteristics of airway bronchoconstriction (i.e., limited peak expiratory flow and a prolonged expiratory phase). These characteristics were found to improve upon narrowing the expiratory port. We believe that this device model will facilitate future mechanical ventilation experiments. PMID:24993492

  15. 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.

  16. 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

  17. 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

  18. 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

  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. [A case of respiratory distress syndrome complicated by the development of interstitial emphysema and pneumomediastinum].

    PubMed

    Zhidkov, K P; Bogatyr', M N; Chezhin, A N; Leĭman, V A; Smirnova, O R

    2000-01-01

    A 15-year-old patient has been admitted to the intensive care unit for severe respiratory distress syndrome that developed as a result of pneumonia. Interstitial lung edema was confirmed by computer-aided tomography. It was successfully treated by positive pressure ventilation (PPV). Although PEEP did not exceed 7 cm H2O, PPV was complicated by interstitial emphysema, pneumomediastinum, and bilateral pneumothorax as a result of barotrauma. Pulmonary artery pressure (PAP) and pulmonary capillary wedge pressure (PCWP) were monitored. High PCWP values were inconsistent with the diagnosis of acute respiratory distress syndrome. The authors suggest that high PCWP was caused by high intraalveolar pressure, pneumomediastinum, and venule constriction in the hypoxic sites of the lung.

  1. 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.

  2. 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.

  3. Genesis of the characteristic pulmonary venous pressure waveform as described by the reservoir-wave model

    PubMed Central

    Bouwmeester, J Christopher; Belenkie, Israel; Shrive, Nigel G; Tyberg, John V

    2014-01-01

    Conventional haemodynamic analysis of pulmonary venous and left atrial (LA) pressure waveforms yields substantial forward and backward waves throughout the cardiac cycle; the reservoir wave model provides an alternative analysis with minimal waves during diastole. Pressure and flow in a single pulmonary vein (PV) and the main pulmonary artery (PA) were measured in anaesthetized dogs and the effects of hypoxia and nitric oxide, volume loading, and positive-end expiratory pressure (PEEP) were observed. The reservoir wave model was used to determine the reservoir contribution to PV pressure and flow. Subtracting reservoir pressure and flow resulted in ‘excess’ quantities which were treated as wave-related. Wave intensity analysis of excess pressure and flow quantified the contributions of waves originating upstream (from the PA) and downstream (from the LA and/or left ventricle (LV)). Major features of the characteristic PV waveform are caused by sequential LA and LV contraction and relaxation creating backward compression (i.e. pressure-increasing) waves followed by decompression (i.e. pressure-decreasing) waves. Mitral valve opening is linked to a backwards decompression wave (i.e. diastolic suction). During late systole and early diastole, forward waves originating in the PA are significant. These waves were attenuated less with volume loading and delayed with PEEP. The reservoir wave model shows that the forward and backward waves are negligible during LV diastasis and that the changes in pressure and flow can be accounted for by the discharge of upstream reservoirs. In sharp contrast, conventional analysis posits forward and backward waves such that much of the energy of the forward wave is opposed by the backward wave. PMID:25015922

  4. 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.

  5. 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

  6. 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.

  7. The frequency response of cerebral autoregulation.

    PubMed

    Fraser, Charles D; Brady, Ken M; Rhee, Christopher J; Easley, R Blaine; Kibler, Kathleen; Smielewski, Peter; Czosnyka, Marek; Kaczka, David W; Andropoulos, Dean B; Rusin, Craig

    2013-07-01

    The frequency-response of pressure autoregulation is not well delineated; therefore, the optimal frequency of arterial blood pressure (ABP) modulation for measuring autoregulation is unknown. We hypothesized that cerebrovascular autoregulation is band-limited and delineated by a cutoff frequency for which ABP variations induce cerebrovascular reactivity. Neonatal swine (n = 8) were anesthetized using constant minute ventilation while positive end-expiratory pressure (PEEP) was modulated between 6 and 0.75 cycles/min (min(-1)). The animals were hemorrhaged until ABP was below the lower limit of autoregulation (LLA), and PEEP modulations were repeated. Vascular reactivity was quantified at each frequency according to the phase lag between ABP and intracranial pressure (ICP) above and below the LLA. Phase differences between ABP and ICP were small for frequencies of >2 min(-1), with no ability to differentiate cerebrovascular reactivity between ABPs above or below the LLA. For frequencies of <2 min(-1), ABP and intracranial pressure (ICP) showed phase shift when measured above LLA and no phase shift when measured below LLA [above vs. below LLA at 1 min(-1): 156° (139-174°) vs. 30° (22-50°); P < 0.001 by two-way ANOVA for both frequency and state of autoregulation]. Data taken above LLA fit a Butterworth high-pass filter model with a cutoff frequency at 1.8 min(-1) (95% confidence interval: 1.5-2.2). Cerebrovascular reactivity occurs for sustained ABP changes lasting 30 s or longer. The ability to distinguish intact and impaired autoregulation was maximized by a 60-s wave (1 min(-1)), which was 100% sensitive and 100% specific in this model.

  8. [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

  9. Genesis of the characteristic pulmonary venous pressure waveform as described by the reservoir-wave model.

    PubMed

    Bouwmeester, J Christopher; Belenkie, Israel; Shrive, Nigel G; Tyberg, John V

    2014-09-01

    Conventional haemodynamic analysis of pulmonary venous and left atrial (LA) pressure waveforms yields substantial forward and backward waves throughout the cardiac cycle; the reservoir wave model provides an alternative analysis with minimal waves during diastole. Pressure and flow in a single pulmonary vein (PV) and the main pulmonary artery (PA) were measured in anaesthetized dogs and the effects of hypoxia and nitric oxide, volume loading, and positive-end expiratory pressure (PEEP) were observed. The reservoir wave model was used to determine the reservoir contribution to PV pressure and flow. Subtracting reservoir pressure and flow resulted in 'excess' quantities which were treated as wave-related.Wave intensity analysis of excess pressure and flow quantified the contributions of waves originating upstream (from the PA) and downstream (from the LA and/or left ventricle (LV)).Major features of the characteristic PV waveform are caused by sequential LA and LV contraction and relaxation creating backward compression (i.e.pressure-increasing) waves followed by decompression (i.e. pressure-decreasing) waves. Mitral valve opening is linked to a backwards decompression wave (i.e. diastolic suction). During late systole and early diastole, forward waves originating in the PA are significant. These waves were attenuated less with volume loading and delayed with PEEP. The reservoir wave model shows that the forward and backward waves are negligible during LV diastasis and that the changes in pressure and flow can be accounted for by the discharge of upstream reservoirs. In sharp contrast, conventional analysis posits forward and backward waves such that much of the energy of the forward wave is opposed by the backward wave.

  10. 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.

  11. 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

  12. The effects of prophylactic expiratory positive airway pressure on the resolution of oleic acid-induced lung injury in dogs.

    PubMed Central

    Luce, J M; Huang, T W; Robertson, H T; Colley, P S; Gronka, R; Nessly, M L; Cheney, F W

    1983-01-01

    It is not known whether positive end-expiratory airway pressure (PEEP) merely improves gas exchange in patients with the adult respiratory distress syndrome (ARDS) or if it also affects the resolution of their lung injury. The present investigation was performed to determine whether expiratory positive airway pressure (EPAP), a form of PEEP, is prophylactic in preventing the lung injury induced by oleic acid in dogs or in enhancing its resolution. Arterial and mixed venous blood gases and functional residual capacity (FRC) were measured in 14 pairs of mongrel dogs with indwelling catheters and permanent tracheostomies. One member of each pair was treated with 10 cm H2O EPAP through a valve attached to the tracheostomy tube. Both dogs received 0.06 ml/kg oleic acid intravenously at hour 0. Measurements were made at three, 12, and 24 hours, when EPAP was discontinued, and over the next six days. Five dog pairs were sacrificed at 72 hours; the other surviving animals were sacrificed at 168 hours. FRC was higher at three, 12, and 24 hours in dogs receiving EPAP than in the untreated dogs. The arterial oxygen tension (PaO2) was higher and the venous admixture (Qva/Qt) was lower at three and 12 hours in the dogs receiving EPAP than in the untreated dogs. However, after 24 hours, no differences were noted between the two groups in FRC, PaO2, Qav/Qt, mortality, final lung compliance to initial lung compliance differences, lung water to dry lung weight ratios, or histology. It is concluded that EPAP improves gas exchange during its administration, but has no demonstrable prophylactic effect on the resolution of lung injury in the oleic acid model of human ARDS. Images Fig. 7. Fig. 7. PMID:6338844

  13. High tidal volume mechanical ventilation-induced lung injury in rats is greater after acid instillation than after sepsis-induced acute lung injury, but does not increase systemic inflammation: an experimental study

    PubMed Central

    2011-01-01

    Background To examine whether acute lung injury from direct and indirect origins differ in susceptibility to ventilator-induced lung injury (VILI) and resultant systemic inflammatory responses. Methods Rats were challenged by acid instillation or 24 h of sepsis induced by cecal ligation and puncture, followed by mechanical ventilation (MV) with either a low tidal volume (Vt) of 6 mL/kg and 5 cm H2O positive end-expiratory pressure (PEEP; LVt acid, LVt sepsis) or with a high Vt of 15 mL/kg and no PEEP (HVt acid, HVt sepsis). Rats sacrificed immediately after acid instillation and non-ventilated septic animals served as controls. Hemodynamic and respiratory variables were monitored. After 4 h, lung wet to dry (W/D) weight ratios, histological lung injury and plasma mediator concentrations were measured. Results Oxygenation and lung compliance decreased after acid instillation as compared to sepsis. Additionally, W/D weight ratios and histological lung injury scores increased after acid instillation as compared to sepsis. MV increased W/D weight ratio and lung injury score, however this effect was mainly attributable to HVt ventilation after acid instillation. Similarly, effects of HVt on oxygenation were only observed after acid instillation. HVt during sepsis did not further affect oxygenation, compliance, W/D weight ratio or lung injury score. Plasma interleukin-6 and tumour necrosis factor-α concentrations were increased after acid instillation as compared to sepsis, but plasma intercellular adhesion molecule-1 concentration increased during sepsis only. In contrast to lung injury parameters, no additional effects of HVt MV after acid instillation on plasma mediator concentrations were observed. Conclusions During MV more severe lung injury develops after acid instillation as compared to sepsis. HVt causes VILI after acid instillation, but not during sepsis. However, this differential effect was not observed in the systemic release of mediators. PMID:22204611

  14. 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

  15. 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.

  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. 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.

  18. 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

  19. 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

  20. 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.

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. Ventilatory strategies in obstructive lung disease.

    PubMed

    Parrilla, Francisco José; Morán, Indalecio; Roche-Campo, Ferran; Mancebo, Jordi

    2014-08-01

    Chronic obstructive pulmonary disease (COPD) is characterized by expiratory flow limitation (EFL) due to progressive airflow obstruction. The various mechanisms that cause EFL are central to understanding the physiopathology of COPD. At the end of expiration, dynamic inflation may occur due to incomplete emptying the lungs. This "extra" volume increases the alveolar pressure at the end of the expiration, resulting in auto-positive end-expiratory pressure (PEEP) or PEEPi. Acute exacerbations of COPD may result in increased airway resistance and inspiratory effort, further leading to dynamic hyperinflation. COPD exacerbations may be triggered by environmental exposures, infections (viral and bacterial), or bronchial inflammation, and may result in worsening respiratory failure requiring mechanical ventilation (MV). Acute exacerbations of COPD need to be distinguished from other events such as cardiac failure or pulmonary emboli. Strategies to treat acute respiratory failure (ARF) in COPD patients include noninvasive ventilation (NIV), pressure support ventilation, and tracheal intubation with MV. In this review, we discuss invasive and noninvasive techniques to address ARF in this patient population. When invasive MV is used, settings should be adjusted in a way that minimizes hyperinflation, while providing reasonable gas exchange, respiratory muscle rest, and proper patient-ventilator interaction. Further, weaning from MV may be difficult in these patients, and factors amenable to pharmacological correction (such as increased bronchial resistance, tracheobronchial infections, and heart failure) are to be systematically searched and treated. In selected patients, early use of NIV may hasten the process of weaning from MV and improve outcomes.

  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. 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.

  12. 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

  13. Acute lung injury after thoracic surgery.

    PubMed

    Eichenbaum, Kenneth D; Neustein, Steven M

    2010-08-01

    In this review, the authors discussed criteria for diagnosing ALI; incidence, etiology, preoperative risk factors, intraoperative management, risk-reduction strategies, treatment, and prognosis. The anesthesiologist needs to maintain an index of suspicion for ALI in the perioperative period of thoracic surgery, particularly after lung resection on the right side. Acute hypoxemia, imaging analysis for diffuse infiltrates, and detecting a noncardiogenic origin for pulmonary edema are important hallmarks of acute lung injury. Conservative intraoperative fluid administration of neutral to slightly negative fluid balance over the postoperative first week can reduce the number of ventilator days. Fluid management may be optimized with the assistance of new imaging techniques, and the anesthesiologist should monitor for transfusion-related lung injuries. Small tidal volumes of 6 mL/kg and low plateau pressures of < or =30 cmH2O may reduce organ and systemic failure. PEEP may improve oxygenation and increases organ failure-free days but has not shown a mortality benefit. The optimal mode of ventilation has not been shown in perioperative studies. Permissive hypercapnia may be needed in order to reduce lung injury from positive-pressure ventilation. NO is not recommended as a treatment. Strategies such as bronchodilation, smoking cessation, steroids, and recruitment maneuvers are unproven to benefit mortality although symptomatically they often have been shown to help ALI patients. Further studies to isolate biomarkers active in the acute setting of lung injury and pharmacologic agents to inhibit inflammatory intermediates may help improve management of this complex disease.

  14. Pulmonar recruitment in acute respiratory distress syndrome. What is the best strategy?

    PubMed

    Santos, Cíntia Lourenço; Samary, Cynthia dos Santos; Fiorio Júnior, Pedro Laurindo; Santos, Bruna Lourenço; Schanaider, Alberto

    2015-01-01

    Supporting patients with acute respiratory distress syndrome (ARDS), using a protective mechanical ventilation strategy characterized by low tidal volume and limitation of positive end-expiratory pressure (PEEP) is a standard practice in the intensive care unit. However, these strategies can promote lung de-recruitment, leading to the cyclic closing and reopening of collapsed alveoli and small airways. Recruitment maneuvers (RM) can be used to augment other methods, like positive end-expiratory pressure and positioning, to improve aerated lung volume. Clinical practice varies widely, and the optimal method and patient selection for recruitment maneuvers have not been determined, considerable uncertainty remaining regarding the appropriateness of RM. This review aims to discuss recent findings about the available types of RM, and compare the effectiveness, indications and adverse effects among them, as well as their impact on morbidity and mortality in ARDS patients. Recent developments include experimental and clinical evidence that a stepwise extended recruitment maneuver may cause an improvement in aerated lung volume and decrease the biological impact seen with the traditionally used sustained inflation, with less adverse effects. Prone positioning can reduce mortality in severe ARDS patients and may be an useful adjunct to recruitment maneuvers and advanced ventilatory strategies, such noisy ventilation and BIVENT, which have been useful in providing lung recruitment.

  15. 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

  16. 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.

  17. [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

  18. The pathogenesis of pulmonary edema in acute pancreatitis.

    PubMed Central

    Warshaw, A L; Lesser, P B; Rie, M; Cullen, D J

    1975-01-01

    Acute pulmonary edema appeared 3 or more days after the onset of acute pancreatitis in 7 patients, an approximate incidence of 8%. The severity of pancreatitis in these patients was characterized by massive requirements for intravenous colloid and by marked hypocalcemia. In addition, at least 5 of the 7 patients had very high serum levels of triglycerides at the time of hospital admission. Hemodynamic studies during pulmonary edema showed normal central venous pressure, pulmonary artery pressure, pulmonary capillary wedge pressure, and pulmonary vascular resistance. Cardiac index was appropriately elevated. Respiratory treatment, consisting of endotracheal intubation and controlled ventilation with PEEP, was successful in allowing reversal of the pulmonary injury and recovery of respiratory function within 1-2 weeks in all cases. Two patients died later from pancreatic abscesses. The findings indicate that a distinct form of pulmonary injury may occur in acute pancreatitis, characterized by loss of integrity of the alveolar-capilllary membrane, leading to pulmonary edema. The mechanism of injury is not known but may be caused by circulating free fatty acids, phospholipase A, or vasoactive substances. The pulmonary membrane lesion appears to heal during the period of intensive respiratory support. Images Fig. 1. PMID:1101836

  19. 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 F(IO2), 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

  20. 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

  1. An evaluation of the safety and efficacy of an anti-inflammatory, pulmonary enteral formula in the treatment of pediatric burn patients with respiratory failure.

    PubMed

    Mayes, Theresa; Gottschlich, Michele M; Kagan, Richard J

    2008-01-01

    Respiratory failure is associated with a high mortality rate in burned children. Recently, a specialized pulmonary enteral formula (SPEF) was commercially introduced as an adjunct intervention in acute lung injury management. SPEF contains condition-specific nutrients to modulate the inflammatory response. The study examined SPEF impact in critically ill, pediatric burn patients with respiratory failure. Medical records of acute burn patients admitted December 1997 to October 2006 were reviewed for SPEF treatment. Respiratory and renal indices were compared on the first and final days of SPEF use. Nineteen patients with respiratory failure received SPEF for a mean of 10.8 +/- 0.9 days during their acute burn course. Mean age was 5.3 +/- 1.5 years. Mean total body surface area burn was 44.3 +/- 5.4% with 32.5 +/- 6.4% full thickness. Patients were admitted 2.3 +/- 0.9 days postburn. Significant improvements in peak pressure, PEEP, FiO2, P:F ratio, Pco2, Po2, and ETco2 were noted. Seventeen of the 19 patients survived despite the fact that 9 of the 19 patients developed severe barotrauma requiring multiple tube thoracotomies, and all 19 had extremely poor prognoses at SPEF initiation. Adult SPEF formula for critically ill, pediatric burn patients with respiratory failure is safe and well tolerated. SPEF seems to facilitate recovery from acute lung injury as evidenced by improvements in oxygenation and pulmonary compliance.

  2. Ventilatory strategies in obstructive lung disease.

    PubMed

    Parrilla, Francisco José; Morán, Indalecio; Roche-Campo, Ferran; Mancebo, Jordi

    2014-08-01

    Chronic obstructive pulmonary disease (COPD) is characterized by expiratory flow limitation (EFL) due to progressive airflow obstruction. The various mechanisms that cause EFL are central to understanding the physiopathology of COPD. At the end of expiration, dynamic inflation may occur due to incomplete emptying the lungs. This "extra" volume increases the alveolar pressure at the end of the expiration, resulting in auto-positive end-expiratory pressure (PEEP) or PEEPi. Acute exacerbations of COPD may result in increased airway resistance and inspiratory effort, further leading to dynamic hyperinflation. COPD exacerbations may be triggered by environmental exposures, infections (viral and bacterial), or bronchial inflammation, and may result in worsening respiratory failure requiring mechanical ventilation (MV). Acute exacerbations of COPD need to be distinguished from other events such as cardiac failure or pulmonary emboli. Strategies to treat acute respiratory failure (ARF) in COPD patients include noninvasive ventilation (NIV), pressure support ventilation, and tracheal intubation with MV. In this review, we discuss invasive and noninvasive techniques to address ARF in this patient population. When invasive MV is used, settings should be adjusted in a way that minimizes hyperinflation, while providing reasonable gas exchange, respiratory muscle rest, and proper patient-ventilator interaction. Further, weaning from MV may be difficult in these patients, and factors amenable to pharmacological correction (such as increased bronchial resistance, tracheobronchial infections, and heart failure) are to be systematically searched and treated. In selected patients, early use of NIV may hasten the process of weaning from MV and improve outcomes. PMID:25111641

  3. Ontogeny of cerebral oxidative metabolism in the chick embryo.

    PubMed

    Gonya-Magee, T; Vannucci, R C

    1982-05-01

    The low cerebral energy requirements of most mammals at birth reflect an immaturity of the central nervous system, and it has been suggested that energy demands in fetuses are even less well developed than in newborns. Furthermore, fetal cerebral energy requirements are presumed to be met predominantly or exclusively by anaerobic glycolysis. To clarify these issues, we investigated cerebral oxidative metabolism in 9-, 14-, 16-, and 19-day-old chick embryos and in newly hatched peeps. Animals were decapitated and quick-frozen in liquid Freon 0--5 min post-mortem. Forebrain extracts were prepared and assayed for ATP, phosphocreatine, glucose, and lactate. Alterations in these metabolites post-decapitation were used to calculate cerebral metabolic rates (delta similar to P) and rates of maximal anaerobic glycolysis (delta lactate). Rates of lactate accumulation during cerebral ischemia increased progressively from embryonic day 9 through hatching. Cerebral metabolic rates were not different in 9-, 14-, and 15-day-old embryos, but increased steadily thereafter. The extent to which total cerebral energy utilization could be derived from anaerobic glycolysis (delta lactate/delta similar to P) increased from a low at day 9 (0.29) to a maximum at day 16 (0.78). The data suggest that, despite the low cerebral metabolic activity of the chick embryo, at no time during development is anaerobic glycolysis capable of entirely supporting the energy needs of the developing brain.

  4. 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.

  5. Negative pressure pulmonary edema after craniotomy through the endonasal transsphenoidal approach

    PubMed Central

    Ou, Mengchan; Luo, Zhen; Liu, Juan; Yang, Yaoxin; Li, Yu

    2015-01-01

    We describe a case of negative pressure pulmonary edema that occurred in the post-anesthesia care unit in a patient who had undergone transsphenoidal resection of a pituitary adenoma. Negative pressure pulmonary edema is an uncommon complication of general anesthesia. In this case, the patient’s nasal cavity had been filled with surgical packs and she had not become accustomed to breathing through her mouth, in addition to her large tongue and small oropharyngeal cavity, residual effect of anesthetic may resulting in tongue falling which caused airway obstruction. The main causative factor is excessive negative intrathoracic pressure generated by the patient’s spontaneous forced inspiration in an effort to overcome the airway obstruction. It typically developed rapidly, and may be life threatening if not diagnosed promptly. After re-intubation for a short period of mechanical ventilation with positive end expiratory pressure (PEEP 10 cm H2O) and a bolus of intravenous furosemide, the patient recovered rapidly and discharged 8 days after surgery. PMID:26131257

  6. Do all mechanically ventilated pediatric patients require continuous capnography?

    PubMed

    Hamel, Donna S; Cheifetz, Ira M

    2006-09-01

    With most patients in modern ICUs requiring mechanical ventilation, any technology that may lead to more optimal ventilatory strategies would be invaluable in the management of critically ill patients. The focus of most ventilator strategies is protecting the lung from the deleterious effects of mechanical ventilation. Every effort is made to minimize the duration of mechanical ventilation while optimizing the potential for successful extubation. A concise organized plan based on objective criteria that is adjusted to meet changes in patient status is clearly recommended. Continuous capnographic monitoring provides clinicians with clear, precise, objective data that may prove beneficial in the design and implementation of mechanical ventilatory strategies. There are no clear-cut methods for achieving the optimal ventilator strategy for a specific patient. Although guidelines and management theories exist throughout the medical literature, in practice, they often merely serve as loose guidelines. The dynamic properties of an acutely ill patient make the management of mechanical ventilation an ongoing process requiring clinical assessment and planning by multidisciplinary members of the patient care team. Comprehensive evaluation of ventilatory management strategies and patient responses must be made by a collaborative effort of physicians, respiratory care practitioners, and nurses. An objective, consistent approach to the overall management is essential. Although still controversial, it is the authors' opinion that volumetric capnograph provides the data necessary to establish adequate gas delivery, optimal PEEP, and effective ventilation with the least amount of mechanical assistance, regardless of clinician or institutional preferences. PMID:16952808

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

    PubMed

    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.

  8. Pumpless arteriovenous carbon dioxide removal: A novel simplified strategy for severe asthma in children.

    PubMed

    Aravantagi, Avinash; Patra, Kamakshya P; Shekar, Suman; Scott, L Keith

    2011-10-01

    Status asthmaticus unresponsive to pharmacotherapy is conventionally managed with mechanical ventilation, which has its inherent challenges due to barotrauma, dynamic hyperinflation and autopositive end-expiratory pressure (auto-PEEP). Extracorporeal membrane oxygenation has been used as a last resort in respiratory failure due to refractory asthma; however, it entails many complications. In contrast, arteriovenous carbon dioxide removal (AVCO(2)R) is a novel strategy that has been shown to be highly effective in adults with acute respiratory failure. Only one pediatric case series of pediatric asthma managed with AVCO(2)R have been published so far. We herein report a case of severe asthma in a 9-year-old boy who developed severe hypercapnia (Pco2 97 mmHg) and acidosis (pH 7.09) despite being on mechanical ventilation. Within 4 h of initiation of AVCO(2)R, PCo(2) drastically reduced to near-normal levels. He was discharged on day 9 of hospital stay without any complications.

  9. Electrical Impedance Tomography During Mechanical Ventilation.

    PubMed

    Walsh, Brian K; Smallwood, Craig D

    2016-10-01

    Electrical impedance tomography (EIT) is a noninvasive, non-radiologic imaging modality that may be useful for the quantification of lung disorders and titration of mechanical ventilation. The principle of operation is based on changes in electrical conductivity that occur as a function of changes in lung volume during ventilation. EIT offers potentially important benefits over standard imaging modalities because the system is portable and non-radiologic and can be applied to patients for long periods of time. Rather than providing a technical dissection of the methods utilized to gather, compile, reconstruct, and display EIT images, the present article seeks to provide an overview of the clinical application of this technology as it relates to monitoring mechanical ventilation and providing decision support at the bedside. EIT has been shown to be useful in the detection of pneumothoraces, quantification of pulmonary edema and comparison of distribution of ventilation between different modes of ventilation and may offer superior individual titration of PEEP and other ventilator parameters compared with existing approaches. Although application of EIT is still primarily done within a research context, it may prove to be a useful bedside tool in the future. However, head-to-head comparisons with existing methods of mechanical ventilation titration in humans need to be conducted before its application in general ICUs can be recommended. PMID:27682815

  10. 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

  11. Effect of lung resection on pleuro-pulmonary mechanics and fluid balance.

    PubMed

    Salito, C; Bovio, D; Orsetti, G; Salati, M; Brunelli, A; Aliverti, A; Miserocchi, G

    2016-01-15

    The aim of the study was to determine in human patients the effect of lung resection on lung compliance and on pleuro-pulmonary fluid balance. Pre and post-operative values of compliance were measured in anesthetized patients undergoing resection for lung cancer (N=11) through double-lumen bronchial intubation. Lung compliance was measured for 10-12 cm H2O increase in alveolar pressure from 5 cm H2O PEEP in control and repeated after resection. No air leak was assessed and pleural fluid was collected during hospital stay. A significant negative correlation (r(2)=0.68) was found between compliance at 10 min and resected mass. Based on the pre-operative estimated lung weight, the decrease in compliance following lung resection exceeded by 10-15% that expected from resected mass. Significant negative relationships were found by relating pleural fluid drainage flow to the remaining lung mass and to post-operative lung compliance. Following lung re-expansion, data suggest a causative relationship between the decrease in compliance and the perturbation in pleuro-pulmonary fluid balance.

  12. Mild hypothermia attenuates changes in respiratory system mechanics and modifies cytokine concentration in bronchoalveolar lavage fluid during low lung volume ventilation.

    PubMed

    Dostál, P; Senkeřík, M; Pařízková, R; Bareš, D; Zivný, P; Zivná, H; Cerný, V

    2010-01-01

    Hypothermia was shown to attenuate ventilator-induced lung injury due to large tidal volumes. It is unclear if the protective effect of hypothermia is maintained under less injurious mechanical ventilation in animals without previous lung injury. Tracheostomized rats were randomly allocated to non-ventilated group (group C) or ventilated groups of normothermia (group N) and mild hypothermia (group H). After two hours of mechanical ventilation with inspiratory fraction of oxygen 1.0, respiratory rate 60 min(-1), tidal volume 10 ml x kg(-1), positive end-expiratory pressure (PEEP) 2 cm H2O or immediately after tracheostomy in non-ventilated animals inspiratory pressures were recorded, rats were sacrificed, pressure-volume (PV) curve of respiratory system constructed, bronchoalveolar lavage (BAL) fluid and aortic blood samples obtained. Group N animals exhibited a higher rise in peak inspiratory pressures in comparison to group H animals. Shift of the PV curve to right, higher total protein and interleukin-6 levels in BAL fluid were observed in normothermia animals in comparison with hypothermia animals and non-ventilated controls. Tumor necrosis factor-alpha was lower in the hypothermia group in comparison with normothermia and non-ventilated groups. Mild hypothermia attenuated changes in respiratory system mechanics and modified cytokine concentration in bronchoalveolar lavage fluid during low lung volume ventilation in animals without previous lung injury.

  13. Ophthalmic considerations in pregnancy

    PubMed Central

    Chawla, Sushil; Chaudhary, Tarun; Aggarwal, S.; Maiti, G.D.; Jaiswal, Kulharsh; Yadav, Jairam

    2013-01-01

    The eyes are our window to the world and offer us an island of vision in the sea of darkness. Equally, the eyes are also a window to peep into what is going on in the milieu interior. Pregnancy is a natural state of physiological stress for the body. Each organ system of the body in a pregnant lady behaves at variation than in a non-pregnant state. A complex interplay exists between how the pregnancy affects the eye and how ocular physiology and pathology may lead to the modification of the management of pregnancy. Added to this is the effect of systemic conditions on the eye which gets modified by pregnancy. An awareness of the interaction of Ophthalmology and Obstetrics for the benefit of the mother and the child requires a basic understanding of these complex interactions. This article aims at presenting to the reader in a simplified and organized manner the common ophthalmic issues encountered in a pregnant woman, their management and the effect of various ophthalmic medication on the fetus. PMID:24600123

  14. [Cardiorespiratory monitoring in the diagnosis and therapy of patients with adult respiratory distress syndrome].

    PubMed

    Pilas, V; Bilić, A; Vranjković, S

    1989-01-01

    In thirty-six patients, meeting clinical criteria for the diagnosis of ARDS, findings of pulmonary functions and results of invasive hemodynamic monitoring have been separately evaluated and compared with normal values. The majority of patients presented with tachypnea having breathing frequency greater than 30/min, vital capacity less than 20 ml/kg body weight, effective pulmonary compliance less than 25 ml/cm H2O, VD/VT greater than 0.6 and D-L shunt greater than 20%. Pulmonary capillary pressure was normal in most patients and pulmonary artery mean pressure and pulmonary vasculary resistance increased. The authors believe that diagnosis of ARDS can be established with greater reliability by use of more complex pulmonary function testing and hemodynamic investigations. An invasive hemodynamic monitoring using a Swan-Ganz catheter gives irreplaceable data for diagnostic and therapeutic decisions in patients with ARDS. It enables an accurate hydration of patients, correct use of diuretics and vasoactive drugs and it is especially useful in controlled application of ventilators and PEEP. PMID:2770399

  15. Nasal midazolam in children, plasma concentrations and the effect on respiration.

    PubMed

    Fösel, T; Hack, C; Knoll, R; Kraus, G B; Larsen, R

    1995-01-01

    Twenty ASA 1 children, one to six years old, weighing 10-20 kg, scheduled for a combination of general and caudal anaesthesia received at random midazolam 0.2, 0.4, or 0.6 mg.kg-1 or NaCl 0.9% (control group) intranasally. Drug or NaCl 0.9% were administered in one nostril, after inhalation induction of anaesthesia, intubation without relaxant and caudal anaesthesia. Spontaneous respiration was via a circle system and fresh gas flow of 6 l.min-1 (N2O/O2 = 2:1), PEEP 5 cm H2O, endtidal halothane 0.4%. Immediately before and 2, 5, 8, 12, 16, 20, 30, 60 and 120 min after application of the drug 2.5 ml blood was sampled for plasma levels of midazolam. Endtidal CO2, respiratory rate, and oxygen saturation were recorded as long as the children were intubated. Endtidal CO2 and respiratory rate showed no statistical difference between the groups at any time, however, in the group receiving 0.6 mg.kg-1, endtidal CO2 increased significantly from 5.3 kPa (41 mm Hg) at the start to 5.9 kPa (45.5 mm Hg) after 30 min. Plasma levels of midazolam were detected 2 min after application in 10 of 15 patients. Median peak levels were found between 12 and 16 min. Medians of peak plasma levels showed no statistical difference between the three groups (0.2 mg.kg-1:111 ng.ml-1, 0.4 mg.kg-1:136 ng.ml-1, 0.6 mg.kg-1:277 ng.ml-1). After 30, 60 and 120 min medians of midazolam plasma concentration were significantly higher in the group 0.6 mg.kg-1.

  16. 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

  17. [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

  18. 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

  19. 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.

  20. Mechanical stress induces lung fibrosis by epithelial-mesenchymal transition (EMT)

    PubMed Central

    Cabrera-Benítez, Nuria E.; Parotto, Matteo; Post, Martin; Han, Bing; Spieth, Peter M.; Cheng, Wei-Erh; Valladares, Francisco; Villar, Jesús; Liu, Mingayo; Sato, Masaaki; Zhang, Haibo; Slutsky, Arthur S.

    2016-01-01

    Rationale Many mechanically ventilated patients with acute respiratory distress syndrome (ARDS) develop pulmonary fibrosis. Stresses induced by mechanical ventilation may explain the development of fibrosis by a number of mechanisms (e.g. damage the alveolar epithelium, biotrauma). Objectives To test the hypothesis that mechanical ventilation plays an important role in the pathogenesis of lung fibrosis. Methods C57BL/6 mice were randomized into four groups: healthy controls; hydrochloric acid (HCl) aspiration alone; vehicle control solution followed 24 h later by mechanical ventilation (peak inspiratory pressure 22 cmH2O and PEEP 2 cmH2O for 2h); and acid aspiration followed 24h later by mechanical ventilation. The animals were monitored for up to 15 days after acid aspiration. To explore the direct effects of mechanical stress on lung fibrotic formation, human lung epithelial cells (BEAS-2B) were exposed to mechanical stretch for up to 48 h. Measurement and Main Results Impaired lung mechanics after mechanical ventilation was associated with increased lung hydroxyproline content, and increased expression of transforming growth factor-β (TGF-β), β-catenin and mesenchymal markers (α-SMA and Vimentin) at both the gene and protein levels. Expression of epithelial markers including cytokeratin-8, E-cadherin and pro-surfactant protein B decreased. Lung histology demonstrated fibrosis formation and potential epithelial-mesenchymal transition (EMT). In vitro direct mechanical stretch of BEAS-2B cells resulted in similar fibrotic and EMT formation. Conclusions Mechanical stress induces lung fibrosis, and EMT may play an important role in mediating the ventilator-induced lung fibrosis. PMID:21926573

  1. 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

  2. [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

  3. 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

  4. Perioperative functional residual capacity.

    PubMed

    Wahba, R W

    1991-04-01

    The literature dealing with the magnitude, mechanism and effects of reduced FRC in the perioperative period is reviewed. During general anaesthesia FRC is reduced by approximately 20%. The reduction is greater in the obese and in patients with COPD. The most likely mechanism is the loss of inspiratory muscle tone of the muscles acting on the rib cage. Gas trapping is an additional mechanism. Lung compliance decreases and airways resistance increases, in large part, due to decreased FRC. The larynx is displaced anteriorly and elongated, making laryngoscopy and intubation more difficult. The change in FRC creates or increases intrapulmonary shunt and areas of low ventilation to perfusion. This is due to the occurrence of compression atelectasis, and to regional changes in mechanics and airway closure which tend to reduce ventilation to dependent lung zones which are still well perfused. Abdominal and thoracic operations tend to increase shunting further. Large tidal volume but not PEEP will improve oxygenation, although both increase FRC. Both FRC and vital capacity are reduced following abdominal and thoracic surgery in a predictable pattern. The mechanism is the combined effect of incisional pain and reflex dysfunction of the diaphragm. Additional effects of thoracic surgery include pleural effusion, cooling of the phrenic nerve and mediastinal widening. Postoperative hypoxaemia is a function of reduced FRC and airway closure. There is no real difference among the various methods of active lung expansion in terms of the speed of restoration of lung function, or in preventing postoperative atelectasis/pneumonia. Epidural analgesia does not influence the rate of recovery of lung function, nor does it prevent atelectasis/pneumonia. PMID:2036700

  5. 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.

  6. 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

  7. Reference values for volumetric capnography-derived non-invasive parameters in healthy individuals.

    PubMed

    Tusman, Gerardo; Gogniat, Emiliano; Bohm, Stephan H; Scandurra, Adriana; Suarez-Sipmann, Fernando; Torroba, Agustin; Casella, Federico; Giannasi, Sergio; Roman, Eduardo San

    2013-06-01

    The aim of this study was to determine typical values for non-invasive volumetric capnography (VCap) parameters for healthy volunteers and anesthetized individuals. VCap was obtained by a capnograph connected to the airway opening. We prospectively studied 33 healthy volunteers 32 ± 6 years of age weighing 70 ± 13 kg at a height of 171 ± 11 cm in the supine position. Data from these volunteers were compared with a cohort of similar healthy anesthetized patients ventilated with the following settings: tidal volume (VT) of 6-8 mL/kg, respiratory rate 10-15 bpm, PEEP of 5-6 cmH₂O and FiO₂ of 0.5. Volunteers showed better clearance of CO₂ compared to anesthetized patients as indicated by (median and interquartile range): (1) an increased elimination of CO₂ per mL of VT of 0.028 (0.005) in volunteers versus 0.023 (0.003) in anesthetized patients, p < 0.05; (2) a lower normalized slope of phase III of 0.26 (0.17) in volunteers versus 0.39 (0.38) in anesthetized patients, p < 0.05; and (3) a lower Bohr dead space ratio of 0.23 (0.05) in volunteers versus 0.28 (0.05) in anesthetized patients, p < 0.05. This study presents reference values for non-invasive volumetric capnography-derived parameters in healthy individuals. Mechanical ventilation and anesthesia altered these values significantly. PMID:23389294

  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.

  9. Increased incidence of sighs (augmented inspiratory efforts) during synchronized intermittent mandatory ventilation (SIMV) in preterm neonates.

    PubMed

    Hummler, H; Gerhardt, T; Gonzalez, A; Claure, N; Everett, R; Bancalari, E

    1997-09-01

    A reflex resulting in a deep, sigh-like inspiratory effort (augmented breath) is frequently triggered during synchronized mechanical ventilation in preterm infants. We studied the incidence of augmented inspiratory efforts and their effect on ventilation and lung compliance during conventional IMV and synchronized IMV (SIMV) in 15 preterm neonates (GA 26.7 +/- 1.5 wks (mean +/- SD), BW 925 +/- 222 g, age 1-8 days). Augmentation of spontaneous inspiratory effort was defined as an esophageal pressure deflection occurring coincident with a synchronized mechanical breath and exceeding the previous unassisted spontaneous effort by more than 50%. The incidence of augmented breaths was higher during SIMV (11.1 +/- 7.7%; P < 0.01) than during conventional IMV (5.1 +/- 6.1%). However, when the synchronized breaths were triggered late (200-300 msec) after the onset of inspiration, augmented breaths occurred no more frequently than during conventional IMV (6.0 +/- 4.7%). The incidence of augmented breaths correlated inversely with dynamic lung compliance (P = 0.014), but was not significantly influenced by a change in PEEP. Although inspiratory effort increased nearly three times during the augmented breaths, tidal volume increased only 12%. The change in tidal volume was limited because the augmented effort reached its maximal negativity only approximately 500 ms after the beginning of the synchronized, mechanical breath and at a time when the mechanical breath had already ended. For this reason the augmented effort did not contribute significantly to minute ventilation, but only prolonged inspiration. Dynamic lung compliance did not change significantly after an augmented breath. The results indicate that augmented inspiratory efforts are more common in preterm neonates ventilated with SIMV than with conventional IMV, but do not contribute significantly to ventilation.

  10. [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

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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

  18. 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

  19. 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

  20. A New Paradigm of Interactive Artery/Vein Separation in Non-Contrast Pulmonary CT Imaging using Multi-Scale Topo-Morphologic Opening

    PubMed Central

    Gao, Zhiyun; Grout, Randall W.; Holtze, Colin; Hoffman, Eric A.

    2014-01-01

    Distinguishing pulmonary arterial and venous (A/V) trees via in vivo imaging is a critical first step in the quantification of vascular geometry for the purpose of diagnosing several pulmonary diseases and to develop new image-based phenotypes. A multi-scale topo-morphologic opening (MSTMO) algorithm has recently been developed in our laboratory for separating A/V trees via non-contrast pulmonary human CT imaging. The method starts with two sets of seeds – one for each of A/V trees and combines fuzzy distance transform and fuzzy connectivity in conjunction with several morphological operations leading to locally-adaptive iterative multi-scale opening of two mutually conjoined structures. In the current paper, we introduce the methods for handling “local update” and “separators” into our previous theoretical formulation and incorporate the algorithm into an effective graphical user interface (GUI). Results of a comprehensive evaluative study assessing both accuracy and reproducibility of the method under the new setup are presented and also, the effectiveness of the GUI-based system towards improving A/V separation results is examined. Accuracy of the method has been evaluated using mathematical phantoms, CT images of contrast-separated pulmonary A/V casting of a pig’s lung and non-contrast pulmonary human CT imaging. The method has achieved 99% true A/V labeling in the cast phantom and, almost, 92% to 94% true labeling in human lung data. Reproducibility of the method has been evaluated using multiuser A/V separation in human CT data along with contrast-enhanced CT images of a pig’s lung at different positive end-expiratory pressures (PEEPs). The method has achieved, almost, 92% to 98% agreements in multi-user A/V labeling with ICC for A/V measures being over 0.96 to 0.99. Effectiveness of the GUI based method has been evaluated on human data in terms of improvements of accuracy of A/V separation results and results have shown 8% to 22% improvements

  1. The effect of changing the sequence of cuff inflation and device fixation with the LMA-Supreme® on device position, ventilatory complications, and airway morbidity: a clinical and fiberscopic study

    PubMed Central

    2014-01-01

    Background The conventional sequence when using supraglottic airway devices is insertion, cuff inflation and fixation. Our hypothesis was that a tighter fit of the cuff and tip could be achieved with a consequently lower incidence of air leak, better separation of gastrointestinal and respiratory tracts and less airway morbidity if the device were first affixed and the cuff then inflated. Methods Our clinical review board approved the study (public registry number DRKS00003174). An LMA Supreme® was inserted into 184 patients undergoing lower limb arthroscopy in propofol-remifentanil anaesthesia who were randomly assigned to either the control (inflation then fixation; n = 92) or study group (fixation then inflation; n = 92). The cuff was inflated to 60 cmH2O. The patients’ lungs were ventilated in pressure-controlled mode with 5 cmH2O PEEP, Pmax to give 6 ml kg-1 tidal volume, and respiratory rate adjusted to end-tidal CO2 of 4.8 and 5.6 kPa. Correct cuff and tip position were determined by leak detection, capnometry trace, oropharyngeal leak pressure, suprasternal notch test, and lube-tube test. Bowl and cuff position and the presence of glottic narrowing were assessed by fiberscopic examination. Postoperative dysphagia, hoarseness and sore throat were assessed with a questionnaire. Ventilatory impairment was defined as a tidal volume < 6 ml kg-1 with Pmax at oropharyngeal leak pressure, glottic narrowing was defined as an angle between the vocal cords under 16 degrees. Results The incidence of incorrect device position (18% vs. 21%), failed ventilation (10% vs. 9%), leak pressure (24.8 vs. 25.2 cmH2O, p = 0.63), failed lube-tube test (16.3% vs. 17.6%) and glottic narrowing (19.3% vs. 14.1%, p = 0.35) was similar in both groups (control vs. study, resp.). When glottic narrowing occurred, it was more frequently associated with ventilatory impairment in the control group (77% vs. 39%; p = 0.04). Airway morbidity was more common in the

  2. Performance of heated humidifiers with a heated wire according to ventilatory settings.

    PubMed

    Nishida, T; Nishimura, M; Fujino, Y; Mashimo, T

    2001-01-01

    Delivering warm, humidified gas to patients is important during mechanical ventilation. Heated humidifiers are effective and popular. The humidifying efficiency is influenced not only by performance and settings of the devices but the settings of ventilator. We compared the efficiency of humidifying devices with a heated wire and servo-controlled function under a variety of ventilator settings. A bench study was done with a TTL model lung. The study took place in the laboratory of the University Hospital, Osaka, Japan. Four devices (MR290 with MR730, MR310 with MR730; both Fisher & Paykel, ConchaTherm IV; Hudson RCI, and HummaxII; METRAN) were tested. Hummax II has been developed recently, and it consists of a heated wire and polyethylene microporous hollow fiber. Both wire and fiber were put inside of an inspiratory circuit, and water vapor is delivered throughout the circuit. The Servo 300 was connected to the TTL with a standard ventilator circuit. The ventilator settings were as follows; minute ventilation (V(E)) 5, 10, and 15 L/min, a respiratory rate of 10 breaths/min, I:E ratio 1:1, 1:2, and 1:4, and no applied PEEP. Humidifying devices were set to maintain the temperature of airway opening at 32 degrees C and 37 degrees C. The greater V(E) the lower the humidity with all devices except Hummax II. Hummax II delivered 100% relative humidity at all ventilator and humidifier settings. When airway temperature control of the devices was set at 32 degrees C, the ConchaTherm IV did not deliver 30 mg/L of vapor, which is the value recommended by American National Standards at all V(E) settings. At 10 and 15 L/min of V(E) settings MR310 with MR730 did not deliver recommended vapor, either. In conclusion, airway temperature setting of the humidifying devices influenced the humidity of inspiratory gas greatly. Ventilatory settings also influenced the humidity of inspiratory gas. The Hummax II delivered sufficient water vapor under a variety of minute ventilation.

  3. [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.

  4. [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

  5. 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

  6. Selective NF-kappaB inhibition, but not dexamethasone, decreases acute lung injury in a newborn piglet airway inflammation model.

    PubMed

    von Bismarck, Philipp; Klemm, Karsten; García Wistädt, Carlos-Francisco; Winoto-Morbach, Supandi; Schütze, Stefan; Krause, Martin F

    2009-08-01

    Acute respiratory failure in neonates (e.g. ARDS, meconium aspiration pneumonitis, pneumonia) is characterized by an excessive inflammatory response, governing the migration of polymorpho-nuclear leukocytes (PMNLs) into lung tissue and causing consecutive impairment of gas exchange and lung function. Critical to this inflammatory response is the activation of nuclear factor-kappaB (NF-kappaB) that is required for transcription of the genes for many pro-inflammatory mediators. We asked whether the inhibition of NF-kappaB activity using either a selective inhibitor (IKK-NBD peptide) or dexamethasone would be more effective in decreasing NF-kappaB activity and chemokine expression in pulmonary cells. Changes in lung function were repeatedly assessed for 24h following induction of acute respiratory failure and therapeutic intervention. We conducted a randomized, controlled, prospective animal study with mechanically ventilated newborn piglets which underwent repeated airway lavage (20+/-2 [SEM]) to remove surfactant and to induce lung inflammation. Admixed to 100 mg kg(-1) surfactant, piglets then received either IKK-NBD peptide (S+IKK), a selective inhibitor of NF-kappaB activation, its control peptide without intrinsic activity, dexamethasone (S+Dexa), its solvent aqua, or an air bolus only (all groups n=8). After 24h of mechanical ventilation, the following differences were measured: PaO(2)/FiO(2) (S+IKK 230+/-9 mm Hg vs. S+Dexa 188+/-14, p<0.05); ventilation efficiency index (0.18+/-0.01 [3800/(PIP-PEEP)(*)f(*)PaCO(2)] vs. 0.14+/-0.01, p<0.05); extravascular lung water (24+/-1 ml kg(-1) vs. 29+/-2, p<0.05); PMNL in BAL fluid (112+/-21 cells microl(-1) vs. 208+/-34, p<0.05), IL-8 (351+/-117 pg ml(-1) vs. 491+/-144, p=ns) and leukotriene B(4) (23+/-7 pg ml(-1) vs. 71+/-11, p<0.01) in BAL fluid. NF-kappaB activity in the nucleus of pulmonary cells differed by 32+/-5% vs. 55+/-3, p<0.001. Differences between these two intervention groups were more pronounced in the

  7. 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.

  8. [Acute respiratory distress syndrome: case series, two years at an intensive care unit].

    PubMed

    Taborda, Lúcia; Barros, Filipa; Fonseca, Vitor; Irimia, Manuel; Carvalho, Ramiro; Diogo, Cláudia; Ramos, Armindo

    2014-01-01

    Introdução: A Síndrome de Dificuldade Respiratória Aguda apresenta incidência e mortalidade significativas em Cuidados Intensivos, justificando estudos adicionais, nomeadamente para definição de novas abordagens terapêuticas. Os autores propuseram-se caracterizaros casos duma Unidade de Cuidados Intensivos em dois anos.Material e Métodos: Procedeu-se a um estudo observacional retrospectivo dos casos admitidos numa Unidade de Cuidados Intensivos, cumprindo os critérios diagnósticos da American-European Consensus Conference on ARDS, tendo sido excluídos os não ventilados invasivamente. Pesquisados e submetidos a tratamento estatístico: dados demográficos, etiologia do Síndrome de Dificuldade Respiratória Aguda, comorbilidades, Índices de Gravidade, PaO2/FiO2, modalidades e parâmetros ventilatórios, compliance pulmonar, dias de ventilação mecânica invasiva, corticoterapia, terapêuticas de resgate, complicações, duração do internamento, óbitos.Resultados: Obtiveram-se 40 doentes, com uma mediana de 72,5 anos (amplitude interquartil 22) e um ratio feminino:masculino ≈1:1,86. Cinquenta e cinco por cento dos Síndrome de Dificuldade Respiratória Aguda tiveram etiologia pulmonar. A média do PaO2/ FiO2 mínimo foi 88mm Hg (IC 95%: 78,5-97,6). A média da PEEP máxima aplicada foi 12,4 cmH2O (Desvio Padrão 4,12) e a médiado Volume Corrente máximo utilizado foi 8,2 mL/Kg peso ideal (IC 95%: 7,7-8,6). A mediana dos dias de ventilação mecânica invasiva foi 10. Em 47,5% dos doentes foram administrados corticóides. Em 52,5% foi executado recrutamento alveolar. A complicação mais frequente foi a Pneumonia Associada a Ventilação (20%). A mediana da duração do internamento foi 10,7 dias (amplitude interquartil10,85). Faleceram 60% dos doentes. A probabilidade de outcome favorável ‘não óbito na Unidade de Cuidados Intensivos’ foi 4,4x superior nos doentes sob corticoterapia e 11x superior nos doentes com idade < 65 anos

  9. [Total intravenous anesthesia (TIVA) in geriatric surgery. S-(+)-ketamine versus alfentanil].

    PubMed

    Adams, H A; Beigl, B; Schmitz, C S; Baltes-Götz, B

    1995-12-01

    In this prospective, randomized study, two regimens of total intravenous anaesthesia (TIVA), with propofol and S(+)-ketamine (S-ketamine) and with propofol and alfentanil, were compared with reference to endocrine stress response, circulatory effects and recovery. METHODS. The investigation was conducted in two groups of 20 ASA I-III patients over 60 years of age who were scheduled for endoprothetic orthopaedic surgery. After oral premedication with midazolam, patients received a TIVA with body-weight-adjusted doses of propofol, and S-ketamine or alfentanil as the analgesic component. For CPPV (PEEP 5 mbar), air and oxygen (FiO2 33%) were used. For muscle relaxation, patients of both groups received vecuronium in body-weight-adjusted doses. Blood samples were taken through a central venous line at seven time points before induction of anaesthesia and on the first morning after the operation also for analysis of epinephrine, norepinephrine (by HPLC/ECD), and ADH, ACTH and cortisol (by RIA). In addition, SAP, HR, arterial oxygen saturation, recovery from anaesthesia and side effects were observed. RESULTS. The two groups had comparable group mean values for age (S-ketamine group 71 years, alfentanil-group 70 years), other biometric data, and duration of anaesthesia and operation (Table 1). Plasma levels of epinephrine, norepinephrine (Table 2, Fig. 1), ADH (Table 2, Fig. 2) ACTH and cortisol (Table 2, Fig. 3) were higher in the S-ketamine-group (P < 0.05) owing to the intraoperative course of these endocrine parameters. Before induction, and on the first morning after the operation, levels were comparable between the groups. 5 min after the induction of anaesthesia, SAP and HR (Table 3) were significantly lower in the alfentanilgroup (P = 0.001). Recovery from anaesthesia (orientation with respect to person and location) was faster in the alfentanilgroup (16 vs 39 min, P = 0.001). An arterial oxygen saturation below 90% was observed in 7 patients in the S