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Die Bedeutung des inspiratorischen Hold und einer verlängerten inspiratorischen Rampe für die Erkennung von pulmopleuralen Leckagen in einem ex vivo Modell
No full textBei den Luftfisteln nach thoraxchirurgischen Eingriffen handelt es sich um eine häufige Komplikation, die eine Reihe von weiteren Problemen nach sich zieht. Die Manipulation am Lungengewebe während der Operation führt zu kleinen Verletzungen und Leckagen, durch die Luft in den Pleuraspalt gelangt. Nicht immer heilen diese Fisteln von selbst ab und führen unter anderem zu einer längeren Liegedauer der Thoraxdrainage, welche mit vielen weiteren Komplikationen (Schmerzen, Infektionsgefahr, Immobilität usw.) verbunden ist. Oft folgen Wiederaufnahmen auf die Intensivstation, allgemein ein verlängerter stationärer Aufenthalt und ggf. sogar erneute chirurgische Interventionen. Das alles mündet in nicht unerheblichen Kosten für das Gesundheitssystem. Die Notwendigkeit, diese Komplikation besser beherrschen zu können, liegt also auf der Hand. In der Regel wird nach Ende der Operation und vor Verschluss des Thorax ein Dichtigkeitstest durchgeführt, um noch intraoperativ entdeckte Leckagen verschließen zu können. Leider scheint dieser Test, in dem die operierte Lunge unter Wasser wiederbelüftet und auf Blasenbildung (als Hinweis auf eine Leckage) beobachtet wird, immer wieder relevante Fisteln zu übersehen, die dann postoperative Komplikationen nach sich ziehen. Wir haben uns mit der Frage beschäftigt, ob das aktuell intraoperativ stattfindende Verfahren zur Detektion der Luftleckagen noch Potenzial zur Verbesserung hat. Es existieren sehr viele Studien zu intra- und postoperativen Verschlussmethoden der Leckagen, zu den klinischen Folgen der Fisteln und zu ihren Risikofaktoren. Allerdings konnten wir auch nach intensiver Literaturrecherche kaum Untersuchungen zum Dichtigkeitstest finden. Der Test ist somit ein wichtiger und kaum beachteter Ansatz, der das Problem der Leckagen an der Wurzel packen könnte.
Wir haben in unserer Arbeit an einem Ex-vivo-Modell mit Schweinelungen untersucht, ob eine Änderung des Beatmungsregimes während des Tests Leckagen besser demaskiert. Möglicherweise reichen die aktuellen Beatmungseinstellungen nicht aus, um die operierte Lunge komplett zu entfalten und somit alle Areale mit potenziellen Leckagen abzubilden. Zwei modifizierende Faktoren haben wir für eine mögliche Verbesserung näher betrachtet: einerseits die inspiratorische Rampe und andererseits das „inspiratory hold“-Manöver. Es wurden drei Gruppen eingeteilt: zunächst die Kontrollgruppe (pinsp= + 25 mbar, PEEP + 5 mbar, Frequenz 10/min), bei der das in der klinischen Praxis durchgeführte Standard-Beatmungs-Verfahren untersucht wurde, die erste Versuchsgruppe mit einer flacheren inspiratorischen Rampe und die zweite Versuchsgruppe, bei der wir ein „inspiratory hold“-Manöver bei + 25 mbar für 5 Sekunden durchführten. Den Präparaten wurden für die Messung zwei verschiedene Läsionen zugefügt, einmal mit 0.8 cm Tiefe und die andere mit 1.8 cm Tiefe. Die ausgetretene Luft wurde mittels eines optischen Scores dokumentiert und zusätzlich durch einen Trichter und eine Blasenspritze auf den Milliliter genau quantifiziert. Die Erhebung des Luftaustritts erfolgte nach 1 Minute und dann erneut nach 5 Minuten Beatmung.
In den Versuchen zeigte sich die Rampengruppe der Standardgruppe nach einer Minute nicht signifikant überlegen, sowohl bei der oberflächlichen (p = 0.07), als auch bei der tiefen Läsion (p = 0,086). Nach 5 Minuten war der Unterschied bei beiden Läsionen sogar zu Gunsten der Kontrollgruppe signifikant (p = 0.026 bzw. p = 0.027). Jedoch konnten wir für die „inspiratory hold“-Manöver-Gruppe einen signifikanten Unterschied im Erkennen der Leckagen im Vergleich zur Kontrollgruppe feststellen. Insbesondere die oberflächliche Läsion konnte durch das Manöver deutlich besser detektiert werden (nach einer Minute p = 0,0016 und nach 5 Minuten p = 0,008). Bei der tiefen Läsion ließ sich ein weniger signifikanter Unterschied erkennen (Nach 1 Minute p = 0.075 und nach 5 Minuten p = 0.024). Tatsächlich sind es die oberflächlichen Läsionen, die in der klinischen Praxis häufiger übersehen und klinisch unterschätzt werden, da die Rekrutierung des Lungengewebes von der Tiefe zur Oberfläche verläuft. Genau hier zeigt sich unser Manöver vielversprechend, vermutlich, da durch das Halten des inspiratorischen Drucks ein optimaleres Aufblähen der Lunge und somit eine Rekrutierung bis in die terminalen oberflächlicheren Atemwege erreicht wird.
Zusammenfassend lässt sich also sagen, dass die intraoperative Erkennung von Luftleckagen durch das „inspiratory hold“-Manöver im Vergleich zum praktizierten Standardvorgehen verbessert werden kann.Air fistulas after thoracic surgery are a common complication that can lead to a number of other problems. Manipulation of the lung tissue during surgery causes small injuries and leaks that allow air to enter the pleural cavity. These fistulas do not always heal on their own and lead to a prolonged period of the chest tube, which is associated with many other complications (pain, risk of infection, immobility, etc.). This is often followed by readmission to the intensive care unit, a generally prolonged inpatient stay and possibly even further surgical interventions, all of which result in significant costs to the healthcare system. The need for better control of this complication is clear. Typically, a leak test is performed at the end of surgery and before the chest is closed in order to repair any leaks discovered during the operation. Unfortunately, this test, which involves re-aerating the operated lung under water and observing the formation of bubbles (as an indication of leakage), often seems to miss relevant fistulae, which then lead to post-operative complications. We have addressed the question of whether there is room for improvement in the current intraoperative method of detecting air leaks. There are many studies on methods of intra- and post-operative air leak closure, the clinical consequences of fistulae and their risk factors. However, even after an intensive search of the literature, we were unable to find any studies on leak testing. The test is therefore an important and little known approach that could address the problem of leakage at its root.
In our work, we used an ex vivo porcine lung model to investigate whether changing the ventilation regime during the test could better detect leaks. It is possible that the current ventilation settings are not sufficient to fully expand the operated lung and thus map all areas of potential leakage. We looked at two modifiers of potential improvement: the inspiratory ramp and the inspiratory hold manoeuvre. There were three groups: a control group (pinsp= + 25 mbar, PEEP + 5 mbar, frequency 10/min) in which the standard ventilation procedure used in clinical practice was studied, the first test group with a flatter inspiratory ramp, and the second test group in which we performed an "inspiratory hold" manoeuvre at + 25 mbar for 5 seconds. Two different lesions were added to the preparations for measurement, one with a depth of 0.8 cm and the other with a depth of 1.8 cm. Air leakage was documented using an optical score and quantified to the nearest millilitre using a funnel and bubble syringe. Air leak was recorded once after 1 minute and again after 5 minutes of ventilation.
In the experiments, the ramp group was not significantly superior to the standard group at 1 minute for either the superficial lesion (p = 0.07) or the deep lesion (p = 0.086). After 5 minutes, the difference was even significant in favour of the control group for both lesions (p = 0.026 and p = 0.027 respectively). However, for the 'inspiratory hold' manoeuvre group, we found a significant difference in leak detection compared to the control group. In particular, the superficial lesion was significantly better detected by the manoeuvre (at 1 minute p = 0.0016 and at 5 minutes p = 0.008). A less significant difference was observed for the deep lesion (at 1 minute p = 0.075 and at 5 minutes p = 0.024). In fact, it is the superficial lesions that are more often overlooked in clinical practice and clinically underestimated, as the recruitment of lung tissue proceeds from depth to surface. This is where our manoeuvre shows promise, presumably because maintaining inspiratory pressure achieves more optimal lung inflation and thus recruitment into the more superficial terminal airways.
In conclusion, intraoperative detection of air leaks can be improved by the "inspiratory hold" manoeuvre compared to the standard procedure
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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