1,720,986 research outputs found
Oxygénation sous ECMO veino-artérielle pour choc cardiogénique
No full textAlthough primarily used to restore hemodynamic, VA ECMO significantly affects arterial oxygenation, and severe hyperoxemia (PaO2 > 300 mmHg) is frequently reported. It is of concern, as several observational studies have reported an association between right radial PaO2 and poor outcome in cardiogenic shock (CS) supported by VA ECMO.Currently it is recommended to avoid hyperoxemia. However, managing PaO2 during peripheral VA ECMO is complex. We first conducted a literature review. In the case of femoro-femoral VA ECMO, there is a differential oxygenation phenomenon. The upper body is perfused by native cardiac output and oxygenated by the lung. Then, PaO2 of the proximal aorta and its first branch (such as brachiocephalic trunk) is affected by inspired oxygen fraction, positive end expiratory pressure, but also by ECMO blood flow and sweep gas oxygen fraction (FSO2). The lower body is perfused and oxygenated by the ECMO, and postoxygenator oxygen partial pressure (PPOSTO2) is mainly determined by FSO2. Despite the major role of FSO2 in ECMO-induced hyperoxemia, little is known about setting of FSO2 in daily practice.Then, we conducted an observational study of 139 patients in 15 ICU, aiming at describing oxygenation practices during VA ECMO support for CS. Median FSO2 from day 1 to 7 was 70% [57-79]. PPOSTO2 was measured in only 28% of patients in 4 centers, and revealed significant hyperoxemia as two third of values were above 150 mmHg. Interestingly, mean right radial PaO2 day1-3, but also mean FSO2 day1-3 were associated with in-ICU mortality.Although it is plausible that hyperoxemia may be harmful by boosting ischemia-reperfusion injuries, it may also be a marker of cardiac failure severity. The mixing zone location, i.e. the point in the aorta where the native and the extracoporeal circulations meet, varies depending on native cardiac output and ECMO support. In the most severe cardiac failure, the mixing zone is proximal in the aorta, before the brachiocephalic trunk, and right radial PaO2 is mainly determined by FSO2. Then, the most hyperoxemic patients may be those with the most severe cardiac failure, having per se a worse prognosis.To determine whether hyperoxemia affects patient outcome or not, we conducted a pilot randomized trial aiming at evaluating the feasibility of a conservative extracorporeal oxygen target strategy (PPOSTO2 100 to 150 mmHg), and comparing it to a liberal one (FSO2 maintained at 100%) regarding to organ dysfunction in the first week of VA ECMO support. The intervention was FSO2 titration based on PPOSTO2 monitoring, at least twice a day. Patients with CS supported by VA ECMO for less than 6 hours were enrolled. The primary outcome was intestinal fatty acid binding protein (IFABP) concentration on day 2, a specific marker of small bowel damage. Secondary outcomes were feasibility, biomarkers of renal and hepatic function from day 0 to 6 after randomization. Fifty-five patients were randomized (29 in conservative arm, 26 in liberal arm). The two arms were well separated: FSO2 61 (±7) % versus 98 (±7) %, and PPOSTO2 130 (±40) mmHg versus 420 (±50) mmHg, in the conservative and liberal arms, respectively. However, in the conservative arm, the median percentage of PPOSTO2 in the target window was only 38% [IQR 20-46], reflecting an important variability of PPOSTO2. There was no difference in IFABP level on day 2, nor in serum creatinine, need for renal replacement therapy, ASAT and prothrombin time.Our results suggest that ECMO-induced hyperoxemia is frequent and underestimated in daily practice, as PPOSTO2 is not routinely monitored. Titrating FSO2 aiming at mild postoxygenator hyperoxemia does not seem to improve organ dysfunction in the first week of VA ECMO support. However, maintaining PPOSTO2 in the target window is difficult. Future research with continuous monitoring of postoxygenator oxygenation is needed to definitively evaluate the benefit of FSO2 titration in VA ECMO.L’hyperoxémie sévère (PaO2>300 mmHg) est rapportée chez 6 à 20 % des patients sous ECMO veino-artérielle (VA) pour choc cardiogénique (CC). Une attention particulière doit y être portée car des études observationnelles ont décrit une association entre PaO2 radiale droite et mortalité dans ce contexte.Nous avons donc d’abord réalisé une revue de littérature. Sous ECMO VA fémoro-fémorale, il existe un phénomène d’oxygénation différentielle. Le haut du corps est perfusé par le cœur et oxygéné par les poumons. La PaO2 de l’aorte proximale est déterminée par la FIO2, la PEP, mais aussi par le débit d’ECMO et la fraction d’oxygène du gaz frais (FSO2). Le bas du corps est perfusé et oxygéné par l’ECMO, et la pression partielle en oxygène mesurée en postoxygénateur (PPOSTO2) est principalement déterminée par FSO2.Malgré le rôle prépondérant de la FSO2 dans l’hyperoxémie induite par l’ECMO, peu de données sont disponibles sur sa gestion au quotidien. Nous avons donc mené une étude rétrospective sur 139 patients dans 15 réanimations, visant à décrire les pratiques d’oxygénation sous ECMO VA pour CC. La FSO2 médiane entre J1 et J7 d’ECMO était de 70%[57-79]. La PPOSTO2, témoin de l’oxygénation hépato-splanchnique et rénale, n’était mesurée que chez 28% des patients, et seulement dans 4 centres. Deux tiers des valeurs étaient supérieures à 150 mmHg, cible recommandée par l’ELSO. La PaO2 radiale droite moyenne J1-J3, mais aussi la FSO2 moyenne J1-J3 étaient associées à la mortalité en réanimation.Bien que l’hyperoxémie puisse aggraver les lésions de reperfusion, elle pourrait aussi n’être qu’un marqueur de gravité. Plus l’insuffisance cardiaque est sévère, plus la localisation de la mixing zone est proximale dans l’aorte. Elle peut alors se trouver en amont du tronc artériel brachiocéphalique. La PaO2 radiale droite est alors déterminée par la FSO2. Les patients les plus hyperoxémiques pourraient donc être ceux avec l’insuffisance cardiaque la plus sévère, ayant de fait un moins bon pronostic.Pour déterminer si l’hyperoxémie affecte ou non le pronostic, nous avons mené un essai randomisé multicentrique pilote visant à évaluer la faisabilité d’une stratégie d’oxygénation extracorporelle conservatrice (PPOSTO2 100-150 mmHg), et à la comparer à une stratégie libérale (FSO2 100%) en terme de dysfonction d’organes sous ECMO VA pour CC. L’intervention était la titration de la FSO2 sous surveillance biquotidienne de la PPOSTO2. Le critère de jugement principal était la concentration plasmatique en IFABP, un marqueur de lésion de l’intestin grêle, mesurée à J2. Les critères secondaires étaient la faisabilité, les fonctions rénale et hépatique à J0, J2 et J6. Cinquante-cinq patients ont été randomisés (29 bras conservateur, 26 bras libéral). Les paramètres d’oxygénation différaient entre les deux bras : FSO2 61(±7) % Vs 98(±7) %, et PPOSTO2 130(±40) mmHg Vs 420(±50) mmHg, respectivement dans les bras conservateur et libéral. Cependant, dans le bras conservateur, le pourcentage médian de valeurs de PPOSTO2 dans la cible n’était que de 38 % [IQR 20-46], reflétant l’importante variabilité de la PPOSTO2. La concentration plasmatique d’IFABP à J2 ne différait pas entre les deux bras. Il n’y avait pas non plus de différence de créatinine, de recours à la dialyse, de transaminases, et de taux de prothrombine.Nos résultats suggèrent que l’hyperoxémie sous ECMO VA est fréquente et même sous-estimée, la PPOSTO2 n’étant pas systématiquement surveillée. La titration de la FSO2 visant une PPOSTO2 entre 100 et 150 mmHg ne semble pas diminuer les dysfonctions d’organes au cours de la première semaine d’ECMO VA, en comparaison à une stratégie libérale d’oxygénation. Cependant, il est difficile de maintenir la PPOSTO2 dans la cible. Des travaux intégrant la surveillance continue de la saturation en oxygène postoxygénateur seraient utiles avant d’écarter définitivement un bénéfice de la titration de la FSO2 chez les patients sous ECMO VA pour CC
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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