Academic literature on the topic 'Plexus blockade'

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Journal articles on the topic "Plexus blockade"

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Baxter, A. G., and D. M. Coventry. "Brachial plexus blockade." Current Anaesthesia & Critical Care 10, no. 3 (June 1999): 164–69. http://dx.doi.org/10.1016/s0953-7112(99)80009-x.

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Al‐Haddad, MF, and DM Coventry. "Brachial plexus blockade." BJA CEPD Reviews 2, no. 2 (April 2002): 33–36. http://dx.doi.org/10.1093/bjacepd/2.2.33.

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Schultz, David M. "Inferior Hypogastric Plexus Blockade: A Transsacral Approach." November 2007 6;10, no. 6;11 (November 14, 2007): 757–63. http://dx.doi.org/10.36076/ppj.2007/10/757.

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Background: Despite recent refinements in the technique of hypogastric plexus blockade, the lower pelvic organs and genitalia are innervated by fibers from the pre-sacral inferior hypogastric plexus and these fibers are not readily blocked using paravertebral or transdiscal approaches. Design: Report of a technique to introduce a transsacral approach to blockade of the inferior hypogastric plexus. Methods: A technique for performing inferior hypogastric plexus blockade by passing a spinal needle through the sacral foramen is described with 15 blocks in 11 patients. Results: Fifteen inferior hypogastric plexus blocks were performed on 11 female patients who presented with chronic pelvic pain. Pelvic pain was decreased following 11 of the procedures with pre- and post-pain scores (SD) of 7.4 (2.3) and 5.0 (2.7), respectively (P < 0.05). There were no complications or unusual occurrences. Conclusions: This block can be performed safely and effectively if the interventionalist has a high degree of familiarity with sacral anatomy, refined needle steering technique, and expertise in fluoroscopy. Properly performed, transsacral blockade of the inferior hypogastric plexus is a safe technique for the diagnosis and treatment of chronic pain conditions involving the lower pelvic viscera. Key words: Pelvic pain, chronic pain, inferior hypogastric plexus block, superior hypogastric plexus, transsacral approach.
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Bollini, Carlos A. "Interscalene brachial plexus blockade." Techniques in Regional Anesthesia and Pain Management 10, no. 3 (July 2006): 89–94. http://dx.doi.org/10.1053/j.trap.2006.07.008.

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Schupfer, Guido K., and Martin Johr. "Infraclavicular Vertical Plexus Blockade." Anesthesia & Analgesia 84, no. 1 (January 1997): 233. http://dx.doi.org/10.1097/00000539-199701000-00058.

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Kubota, Y., T. Okamoto, and Y. Ueda. "Continuous brachial plexus blockade." Anaesthesia 45, no. 6 (June 1990): 497. http://dx.doi.org/10.1111/j.1365-2044.1990.tb14359.x.

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Sarma, V. J. "Continuous brachial plexus blockade." Anaesthesia 45, no. 8 (August 1990): 695. http://dx.doi.org/10.1111/j.1365-2044.1990.tb14421.x.

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Chin, Ki Jinn, Anahi Perlas, Vincent Chan, and Richard Brull. "Continuous Infraclavicular Plexus Blockade." Anesthesia & Analgesia 109, no. 4 (October 2009): 1347–48. http://dx.doi.org/10.1213/ane.0b013e3181b10103.

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Schupfer, Guido K., and Martin Johr. "Infraclavicular Vertical Plexus Blockade." Anesthesia & Analgesia 84, no. 1 (January 1997): 233. http://dx.doi.org/10.1213/00000539-199701000-00058.

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Geiger, P., and H. H. Mehrkens. "Vertical infraclavicular brachial plexus blockade." Techniques in Regional Anesthesia and Pain Management 7, no. 2 (April 2003): 67–71. http://dx.doi.org/10.1053/trap.2003.000119.

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Dissertations / Theses on the topic "Plexus blockade"

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Beier, David [Verfasser]. "Detektion der Nadel-Nerv-Distanz unter Elektrostimulation zur interskalenären Plexus-brachialis-Blockade - eine ex post Ultraschallanalyse / David Beier." Greifswald : Universitätsbibliothek Greifswald, 2017. http://d-nb.info/1127882120/34.

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Klepcha, Ioulia [Verfasser], and Dieter [Akademischer Betreuer] Heuser. "Effizienz und Effektivität der sonographisch gesteuerten Lokalanästhetika- Applikation bei axillärer Plexus brachialis - Blockade / Ioulia Klepcha ; Betreuer: Dieter Heuser." Tübingen : Universitätsbibliothek Tübingen, 2011. http://d-nb.info/1161464794/34.

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Vollhardt, Stefan [Verfasser], and Stefan [Akademischer Betreuer] Kleinschmidt. "Die ultraschallgesteuerte Blockade des axillären Plexus brachialis : Ein Vergleich der Erfolgsrate zwischen ultraschallgesteuerter Blockade, elektrischer Stimulation mit immobiler Nadel, Kältestimulation und ohne Stimulationstechnik / Stefan Vollhardt. Betreuer: Stefan Kleinschmidt." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2013. http://d-nb.info/1052909558/34.

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Lötscher, Stefan. "Single shot and continuous interscalene brachial plexus blockade for shoulder surgery : efficacy and side effects in a teaching hospital /." [S.l.] : [s.n.], 2009. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.

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Eichholz, Rüdiger [Verfasser], and Reinhold [Akademischer Betreuer] Fretschner. "Ultraschallgesteuerte interskalenäre Blockade des Plexus brachialis bei elektiven Schultereingriffen in Regionalanästhesie mit Sedierung : Vergleich der Inzidenz unerwünschter Nervus phrenicus-Blockaden bei anteriorem und posteriorem Zugang. Eine prospektive, randomisierte, kontrollierte einfache Blindstudie / Rüdiger Eichholz ; Betreuer: Reinhold Fretschner." Tübingen : Universitätsbibliothek Tübingen, 2014. http://d-nb.info/1160754616/34.

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Langer, Martin [Verfasser], and Reinhold [Akademischer Betreuer] Fretschner. "Ultraschallgesteuerte Blockade des Plexus cervicalis zu Operationen an der extracraniellen Arteria carotis. Untersuchung auf Wirksamkeit und Darstellung auftretender unerwünschter Wirkungen : eine prospektive, klinische Observationsstudie / Martin Langer ; Betreuer: Reinhold Fretschner." Tübingen : Universitätsbibliothek Tübingen, 2017. http://d-nb.info/119961534X/34.

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Surek, Nicole [Verfasser], Konrad [Akademischer Betreuer] Reinhart, Michael [Akademischer Betreuer] Hartmann, and Andreas [Akademischer Betreuer] Meier-Hellmann. "Retrospektiver Vergleich zwischen axillärer, vertikaler infraklavikulärer und lateraler sagittaler infraklavikulärer Blockade des Plexus brachialis in Bezug auf Effektivität und intraoperative Schmerzfreiheit / Nicole Surek. Gutachter: Konrad Reinhart ; Michael Hartmann ; Andreas Meier-Hellmann." Jena : Thüringer Universitäts- und Landesbibliothek Jena, 2015. http://d-nb.info/1074139267/34.

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Björkman, Maria, and Susanna Ingemarsson. "Kvinnors smärtupplevelse efter dagkirurgisk operation av distal radiusfraktur : En jämförelse mellan plexusblockad och infiltrationsanestesi." Thesis, Högskolan i Borås, Akademin för vård, arbetsliv och välfärd, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-26271.

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Bakgrund: Distal radiusfraktur är den vanligaste frakturen i Sverige där kvinnor drab-bas oftare än män. Majoriteten av de patienter som opereras vårdas på en dagkirurgisk enhet och sköter sin egenvård i hemmet. Kvinnor upplever smärta annorlunda än män vilket kan ha betydelse i valet av smärtlindringsstrategi. Inför operationen erhåller patienten antingen en plexusblockad eller generell anestesi med infiltrationsanestesi i smärtlindrande syfte. I anestesisjuksköterskans kompetensbeskrivning ingår det att ansvara för planering och övervakning vid dessa olika anestesimetoder. Vilken av de två anestesimetoder som används varierar på sjukhusen runt om i Sverige. Det finns ett begränsat forskningsunderlag på vilken anestesimetod som är att föredra. Syfte: Syftet var att undersöka smärtupplevelsen hos kvinnor efter dagkirurgisk operation av distal radiusfraktur. En jämförelse mellan anestesimetoderna plexusblockad och infiltrationsanestesi med Ropivacain. Metod: En kvantitativ enkätundersökning. Data har samlats in genom ett bekvämlighetsurval där enkäten bestående av strukturerade frågor har delats ut av personal på sju postoperativa avdelningar. Resultat: Inga statistiskt signifikanta skillnader har hittats mellan grupperna som erhållit antingen plexusblockad eller infiltrationsanestesi med Ropivacain. Dock visade sig en betydande andel uppleva svår eller värsta tänkbara smärta kvällen eller natten efter operation. Båda grupperna uppvisar även problem med sömn och vila postoperativt. Slutsatser: Resultatet från magisteruppsatsen antyder att det finns förbättringspotential postoperativt för kvinnor med radiusfraktur som upplever smärta. Dessutom bör grundläggande behov, särskilt vila, sömn och aptit, tas i beaktande.
Background: Distal radius fracture is the most common fracture in Sweden and women are affected more often than men. The majority of the patients who require surgery are cared for in a day surgery unit. They are then responsible for their own care at home. Women experience pain differently than men and this can be important when deciding upon a pain relief strategy. Prior to surgery, the patient receives either a plexus blockade or general anesthesia with infiltration anesthesia for pain relief purposes. The nurse anesthetist´s (CRNA) competence description includes being responsible for planning and monitoring of these different anesthesia methods. The choice of anesthesia method used varies in hospitals around Sweden. There is a limited amount of research on which anesthesia method is preferable. Method: A quantitative survey. Data has been collected using convenience sampling where a questionnaire consisting of structured questions was distributed by hospital staff in seven postoperative departments. Results: No statistically significant differences were found between the groups that received either plexus block or ropivacaine infiltration anesthesia. However, a significant proportion were found to experience either severe pain or the worst possible pain in the evening or night after surgery. Both groups show problems with sleep and rest postoperatively, while the infiltration group tends to be more inconvenienced by decreased appetite than the patients in the plexus group. Conclusions: The results of the master's thesis suggest that there is potential for improvement for postoperative female patients with a radius fracture experiencing pain. Additionally basic needs, in particular rest, sleep and appetite, should be taken into account.
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Ebers, Stephan Verfasser], and Alf [Akademischer Betreuer] [Kozian. "Die ultraschallgestützte interskalenäre Blockade des Plexus brachiales für operative Interventionen an der Schulter : ein prospektiver randomisierter Vergleich von erfahrenen Anwendern der Nervenstimulation mit ungeübten Anwendern der ultraschallgestützten Punktion / Stephan Ebers. Betreuer: Alf Kozian." Magdeburg : Universitätsbibliothek, 2014. http://d-nb.info/1054638470/34.

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Wirnharter, Bianca [Verfasser]. "Retrospektive Untersuchung zur Erfolgsrate verschiedener Blockaden des Plexus brachialis / Bianca Wirnharter." Ulm : Universität Ulm. Medizinische Fakultät, 2012. http://d-nb.info/1019167815/34.

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Books on the topic "Plexus blockade"

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Lerman, Imanuel R., Joseph Hung, Dmitri Souzdalnitski, Bruce Vrooman, and Mihir Kamdar. Celiac Plexus Blockade and Neurolysis: Fluoroscopy. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199908004.003.0032.

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Image-guided celiac plexus neurolysis can provide substantial and long-lasting pain relief in patients suffering from malignant pain from upper abdominal viscera. When performed by experienced hands, celiac plexus neurolysis also appears to be a relatively safe procedure with a limited side effect profile. Multiple imaging modalities are available for this procedure, though no single approach has systematically been proven superior in terms of efficacy or side effect profile. Each imaging guidance modality has advantages and disadvantages. Given the ability to visualize soft-tissue structures, CT guidance is recommended over fluoroscopy when intentionally transgressing into the retroperitoneum for celiac plexus neurolysis. It is also recommended in those patients with complicated anatomy, where anatomic distortion may complicate successful celiac blockade. However, in the patient without significant tumor burden involving the celiac axis and/or pancreatic body/tail, the fluoroscopy-guided retrocrural approach has been demonstrated to be efficacious, and complications are exceedingly rare.
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Narouze, Samer N. Celiac Plexus Blockade and Neurolysis: Ultrasound. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199908004.003.0033.

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There has been a growing interest in ultrasound-guided celiac plexus blocks, especially neurolytic blocks, for terminally ill patients with upper abdominal malignancies. These patients are usually frail and difficult to transfer to the radiology suite. Ultrasound-guided celiac plexus neurolytic block can be performed at the bedside with appropriate monitoring. This chapter focuses on ultrasound guidance. It reviews the advantages of ultrasound compared with other imaging modalities in celiac plexus block as well as the step-by-step technique and how to avoid complications.
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Narouze, Samer N. Celiac Plexus Blockade and Neurolysis: Computed Tomography. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199908004.003.0034.

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Computed tomography–guided celiac plexus interventions, especially neurolytic blocks, have become a popular technique as neurolytic blocks require precise placement of the needle into the plexus and careful monitoring of the spread of the neurolytic solution to minimize potential complications. The chapter focuses on CT guidance. It reviews the advantages of CT compared with other imaging modalities in celiac plexus blocks (CPBs) as well as the step-by-step technique and how to avoid complications.
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DiMuro, John M., and Mehul J. Desai. Sympathetic Blockade of the Spine. Edited by Mehul J. Desai. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780199350940.003.0030.

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This chapter focuses on the typical pain complaints and their appropriateness for sympathetic blockade and neurolysis. Anatomic considerations, block technique, associated risks, and evidence of a successful block are covered for the stellate ganglion block, T2 sympathetic block, thoracic splanchnic block, celiac plexus block, superior hypogastric plexus block, and ganglion of impar block. Sympathetic blockade is commonly used for visceral pain syndromes. Visceral pain syndromes typically are not responsive to neuraxial blocks as well as conventional rehabilitative and pharmacologic treatments. Spinal sympathetic techniques involve careful prevertebral needle placement, typically using fluoroscopic guidance. The proximity of major vessels near the target injection area is the primary risk of these techniques. In general, sympathetic blocks are non-diagnostic, but they can still help determine whether a sympathetically mediated pain condition may be present and if sympatholysis may be an effective treatment option.
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Phillips, Alistair, and Harry Akerman. Anaesthesia. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198757689.003.0003.

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Pain-free surgery can be imposed on the hand and wrist without resort to general anaesthetic. Options include local anaesthetic infiltration which can, in higher volumes mixed with adrenaline, allow surgery without a tourniquet. This technique (wide awake local anaesthetic without tourniquet or WALANT) permits the patient to move the fingers without the muscle paralysis induced by the regional anaesthetic and tourniquet, adding invaluable information, e.g. in tendon transfers. The efficacy of specific peripheral nerve blockade and brachial plexus block can be enhanced by ultrasound or nerve stimulation. Intravenous blockade (Bier’s) is effective. Tourniquets (finger, forearm, above elbow) are essential in hand surgery to provide a view unimpeded by blood (although WALANT can achieve this at the expense of a more oedematous field for procedures in a small field).
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McCartney, Colin J. L., and Alan J. R. Macfarlane. Regional anaesthesia of the upper limb. Edited by Philip M. Hopkins. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780199642045.003.0054.

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Peripheral nerve blocks of the upper limb can provide excellent anaesthesia and postoperative analgesia. A variety of well-established traditional approaches to the brachial plexus exist, namely interscalene, supraclavicular, infraclavicular, and axillary techniques. Individual terminal nerves such as the median, radial, ulnar, and other smaller nerves can also be blocked more distally. The traditional and ultrasound-guided approach to each of these nerve blocks is discussed in turn in this chapter, along with specific indications and complications. The introduction of ultrasound guidance has generated significant excitement in this field in the last 10 years and has been demonstrated to improve efficacy and reduce complications. However, a sound knowledge of anatomy of the nerve supply to the upper limb remains essential during any upper limb regional anaesthesia technique.
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E, Harrington Douglas, and United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch., eds. Experimental evaluation of blockage ratio and plenum evacuation system flow effects on pressure distribution for bodies of revolution in 0.1-scale model test section of NASA Lewis Research Center's proposed altitude wind tunnel. [Washington, D.C.]: National Aeronautics and Space Administration, Scientific and Technical Information Branch, 1987.

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Book chapters on the topic "Plexus blockade"

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Konrad, Christoph, Mattias Casutt, and Roland Albrecht. "Plexus-cervicalis-Blockade." In Ultraschallgestützte Regionalanästhesie, 243–52. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-20167-7_26.

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Raj, Prithvi, Hans Nolte, and Michael Stanton-Hicks. "Blockade des sakrokokzygealen Plexus." In Atlas der Regionalanästhesie, 65–73. Berlin, Heidelberg: Springer Berlin Heidelberg, 1988. http://dx.doi.org/10.1007/978-3-642-61385-2_9.

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Fujii-Lau, Larissa L., Maurits J. Wiersema, and Michael J. Levy. "Celiac Plexus Blockade/Neurolysis." In Endoscopic Ultrasound Management of Pancreatic Lesions, 201–10. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-71937-1_16.

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Craß, Dietmar, Florian Gerheuser, and Ulrich Schwemmer. "Periphere Regionalanästhesie: Plexus-cervicalis-Blockade." In Die Anästhesiologie, 1–4. Berlin, Heidelberg: Springer Berlin Heidelberg, 2017. http://dx.doi.org/10.1007/978-3-662-45539-5_54-1.

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Singh, Vikesh K. "Endoscopic management: celiac plexus blockade." In Pancreatitis, 249–55. Chichester, UK: John Wiley & Sons, Ltd, 2017. http://dx.doi.org/10.1002/9781118924907.ch15c.

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Craß, Dietmar, Florian Gerheuser, and Ulrich Schwemmer. "Periphere Regionalanästhesie: Plexus-cervicalis-Blockade." In Springer Reference Medizin, 879–82. Berlin, Heidelberg: Springer Berlin Heidelberg, 2019. http://dx.doi.org/10.1007/978-3-662-54507-2_54.

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Nakamoto, Tatsuo. "Ultrasound-Guided Lumbar Plexus Block." In Nerve Blockade and Interventional Therapy, 177–80. Tokyo: Springer Japan, 2019. http://dx.doi.org/10.1007/978-4-431-54660-3_44.

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Nishie, Hiroyuki. "Superficial Cervical Plexus Block (Landmark, Ultrasound-Guided)." In Nerve Blockade and Interventional Therapy, 79–81. Tokyo: Springer Japan, 2019. http://dx.doi.org/10.1007/978-4-431-54660-3_21.

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Fujii-Lau, Larissa L., Maurits J. Wiersema, and Michael J. Levy. "EUS-Guided Celiac Plexus Blockade/Neurolysis." In Therapeutic Endoscopic Ultrasound, 219–30. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-28964-5_14.

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Raj, Prithvi, Hans Nolte, and Michael Stanton-Hicks. "Blockade des Plexus cervicalis: oberflächlich und tief." In Atlas der Regionalanästhesie, 69–76. Berlin, Heidelberg: Springer Berlin Heidelberg, 1988. http://dx.doi.org/10.1007/978-3-642-61388-3_12.

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Conference papers on the topic "Plexus blockade"

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Schöll, E., and L. Vigh. "Ultraschall-gestützte Blockade einzelner Äste des Plexus cervicalis in der Notfallambulanz." In Interdisziplinärer Kongress | Ultraschall 2019 – 43. Dreiländertreffen DEGUM | ÖGUM | SGUM. Georg Thieme Verlag KG, 2019. http://dx.doi.org/10.1055/s-0039-1695891.

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Martinez-Camacho, A., V. Valera, C. Ruiz, A. Ruiz, JA Gracia, and X. Sala-Blanch. "ESRA19-0319 Triceps brachialis response of radial nerve assessed with neurostimulation during axillary plexus blockade: clinical, anatomical and histological correlation." In Abstracts of the European Society of Regional Anesthesia, September 11–14, 2019. BMJ Publishing Group Ltd, 2019. http://dx.doi.org/10.1136/rapm-2019-esraabs2019.381.

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Di Piazza, I., M. Tarantino, F. Magugliani, and A. Alemberti. "A CFD Analysis of Flow Blockage Phenomena in ALFRED LFR DEMO Fuel Assembly." In 2014 22nd International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icone22-30777.

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A CFD study has been carried out on fluid flow and heat transfer in the HLM-cooled Fuel Pin Bundle of the ALFRED LFR DEMO. In the context of GEN-IV Heavy Liquid Metal-cooled reactors safety studies, the flow blockage in a Fuel sub-assembly is considered one of the main issues to be addressed and the most important and realistic accident for LFR Fuel Assembly. The present paper is a first step towards a detailed analysis of such phenomena, and a CFD model and approach is presented to have a detailed thermo-fluid dynamic picture in the case of blockage. The closed hexagonal, grid-spaced fuel assembly of the LFR ALFRED has been modeled and computed. At this stage, the details of the spacer grids have not been included, but a conservative analysis has been carried out based on the current main geometrical and physical features. Reactivity feedback, as well as axial power profile, have not been included in this analysis. Results indicate that critical conditions, with clad temperatures around ∼900°C, are reached with blockage larger than 30% in terms of area fraction. Two main effects can be distinguished: a local effect in the wake/recirculation region downstream the blockage and a global effect due to the lower mass flow rate in the blocked subchannels; the former effect gives rise to a temperature peak behind the blockage and it is dominant for large blockages (>20%), while the latter effect determines a temperature peak at the end of the active region and it is dominant for small blockages (<10%). The blockage area has been placed at the beginning of the active region, so that both over-mentioned phenomena can fully take place. The mass flow rate at the different degree of blockage has been imposed from preliminary system code simulations. Transient analyses with fully resolved SST-ω turbulence model have been carried out and results indicate that a blockage of ∼15% (in terms of blocked area) leads to a maximum clad temperature around 800 °C, and this condition is reached in a characteristic time of 3–4 s without overshoot. Local clad temperatures around 1000 °C can be reached for blockages of 30% or more. CFD simulations indicate that Blockages >15% could be detected by putting some thermocouples in the plenum region of the FA.
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Bhopte, Siddharth, Bahgat Sammakia, Madhusudan K. Iyengar, and Roger Schmidt. "Experimental Investigation of the Impact of Under Floor Blockages on Flow Distribution in a Data Center Cell." In ASME 2007 InterPACK Conference collocated with the ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/ipack2007-33540.

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Due to the increase in the rack power of computer equipment, in recent years, thermal management of data centers has become a challenging problem. Data center facilities with raised floor plenums are the most popular configuration from a ducting configuration perspective. The under floor plenum serves as a distribution chamber for the cooling air. Plenums are also used to route piping, conduits and cables that bring power, server network connections, and supply coolant to the air conditioning units. Computational modeling studies have shown that, these under floor blockages impede the flow of cold air from the air conditioning units and yield unpredictable air flow patterns. In this paper, the impact of under floor blockages on flow distribution in a data center is experimentally investigated. A data center experimental cell with one server rack and one air conditioning unit is examined. A number of perforated tiles and their resistances are altered to achieve variable flow patterns under the raised floor. Using previously established guidelines for the placement of under floor structures (piping, etc.) three different scenarios are studied, i.e. no blockages, blockages in critical flow path and blockages in safe flow path are considered. Experiments were carried out for two different tile designs, with free area ratios of 16% and 30%, respectively, and three tile configurations. A detailed comparison between the experimental and CFD model results are presented for several different cases, showing good agreement. Blockages if placed in critical path are shown to significantly reduce the supply tile flow rates which directly affects the thermal performance of the corresponding server. Blockages are shown to have minimal impact when they are placed in safe path. Based on CFD model and experimental results, guidelines on managing under floor blockages are verified. Emphasis has been given to the routing the blockages from safe paths and to keeping critical paths blockage free.
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Lavan Kumar, Gundeti, Kiran Vunnam, Bruce Bouldin, and Yogi Sheoran. "Investigation of Plenum Inlet Distortion and its Impact on Compressor Total Pressure and Swirl Distortion." In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-94981.

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Aircraft auxiliary power unit (APU) compressors experience a wide range of total pressure and swirl distortion levels as a result of the APU inlet geometry and different flight conditions and wind directions. Compressors are designed to operate with certain levels of distortion while avoiding surge and stall and maintaining acceptable stress levels. For a new APU development program, the engine compression systems are subjected to a series of tests to evaluate their structural integrity and operability response to different levels of distortion. Most large APUs incorporate two compressor systems. The engine compressor (E/C) makes up the compression system of the gas turbine engine. The load compressor (L/C) supplies air to the airplane for use by its environmental control system (ECS) and for main engine starting. The E/C and the L/C are situated opposite each other within a plenum and jointly pull air from this common plenum. Because both compression systems are positioned deep within the plenum, it is not possible to apply a distortion inducing blockage or measure distortion levels (similar to ones defined in SAE ARP1420) directly at the compressor faces. Instead, it is customary to apply the blockage using metal plates at the inlet to the plenum. This station is typically called the Aerodynamic Interface Plane (AIP) which is defined as the interface between the customer inlet system and the engine inlet plenum. An AIP defined at the plenum entry plane combined with a unique distortion descriptor defined at this plane are useful for many shaft engine applications. This distortion descriptor is directly related to the angular momentum entering the plenum which is converted inside of the plenum into compressor inlet swirl at the compressor eyes. The resulting distortion levels are measured using an array of static pressure, total pressure and total temperature probes placed just downstream of the blockage plates. Because of the physical distance between where the distortion is generated and the APU compressor faces, the amount of distortion seen by the compressors for a given blockage plate configuration is unknown. Consequently, a series of steady state CFD analyses were conducted to evaluate the airflow pattern within the plenum and the resulting compressor face distortion for a given level of distortion induced at the plenum inlet. Both total pressure and swirl distortion levels are evaluated. This CFD analysis evaluated several different plate configurations which result in 15% to 50% blockage of the plenum inlet. Additionally, four different APU plenum configurations were analyzed, some from existing APU installations and another from an APU installation currently in development. This paper discusses the theories behind plenum distortion and its impact on compressor performance. Honeywell’s methodology for the calculation of plenum distortion is described and its benefit in understanding the influence of distortion on compressor operability is explained. This paper describes details of the CFD analysis and presents predicted airflow patterns within the plenums and distortion levels at the compressor faces. The aerodynamics of the different plenum shapes are contrasted and compared with suggestions for future APU plenum designs. Flow visualization techniques are used on an existing plenum to validate the CFD analysis.
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Bhopte, Siddharth, Madhusudan K. Iyengar, Bahgat Sammakia, Roger Schmidt, and Dereje Agonafer. "Numerical Modeling of Data Center Clusters: Impact of Model Complexity." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-13494.

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Data centers are facilities that house large numbers of computer servers that dissipate high power. With the rapid increase in the heat flux of such systems, their thermal management has become a challenge that needs to be addressed. Computational analyses using a CFD code is a very useful technique that helps the engineer to understand and solve the data center cooling problem. In this paper the state of the art of numerical modeling of data center is discussed. Representative systems are modeled using the two most prominent approaches. Variation in results with the addition of modeling details is presented. The effect of under floor parameters such as the conditioned chilled air supply flow rate, the under floor plenum depth, and the tile opening flow resistance, is discussed. Total flow rate delivered by the Computer Room Air Conditioning (CRAC) unit depends on blower and system characteristic curves, as specified by the vendor. Impact of plenum depth and tile resistance on total CRAC flow rate is discussed. Under floor blockages such as cables, pipes, and random materials, impede the flow of the cold air stream and yield unpredictable air flow patterns. Currently, models with idealized plenums are used for simulation of data centers. The effect of including blockages in CFD analyses is discussed. A novel approach that defines safe and critical paths under plenum for routing the blockages is presented.
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Yen, Joseph C., William R. Martindale, and Edward G. Duell. "The Plenum Method Versus Blockage Corrected Nozzle Method for Determining Climatic Wind Tunnel Air Speed." In SAE 2004 World Congress & Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2004. http://dx.doi.org/10.4271/2004-01-0668.

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Bhopte, Siddharth, Bahgat Sammakia, Madhusudan K. Iyengar, and Roger Schmidt. "Guidelines on Managing Under Floor Blockages for Improved Data Center Performance." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-13711.

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Due to the increase in computer rack equipment power in recent years, thermal management of data centers has become a challenging problem. Data center facilities with raised floor plenums are the most popular configuration from a thermal management perspective. Considerable ongoing research efforts focus on optimizing the room layouts and equipment design in order to achieve the desired cooling. However, the detrimental impact of under floor blockages, which occur widely, is seldom addressed. These blockages often take the form of chiller pipes, cabling, and wires. They impede the flow of cold air from the air conditioning units and yield unpredictable air flow patterns. This results in highly maldistributed tile flow rates which can create additional hot spots above the raised floors. In this paper the effect of such under floor blockages on data center performance is characterized in detail. A representative data center is modeled using commercial CFD code, with typical under floor blockages. Blockages are shown to have a significant impact on tile flow rates and rack inlet temperatures. A detailed parametric study is presented, to identify the locations under the floor, where blockages if installed, have minimal effect on data center performance. Case studies are presented to show that blockages, if installed with prior consideration, have a positive effect on overall data center performance. Finally guidelines are presented on how to rearrange existing blockages or to install new blockages, and still achieve an improvement in thermal performance, without any change to the room layout or cold air supply.
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Ieronymidis, Ioannis, David R. H. Gillespie, Peter T. Ireland, and Robert Kingston. "The Use of High Blockage Ribs to Enhance Heat Transfer Coefficient Distributions in a Model of an Integrally Cast Cooling Manifold." In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-91237.

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In this paper detailed experimental measurements and computational predictions of heat transfer coefficient distributions in a large scale perspex model of a novel integrally cast blade cooling geometry are reported. In a gas turbine blade, the cooling passage investigated is integrally cast into the blade wall, providing good thermal contact with the outer surface of the turbine blade. Flow enters the racetrack passage through the root of the blade and exits to a central plenum through a series of nineteen transfer holes equally spaced in a staggered arrangement across the span of the blade. The Reynolds number changes continuously along the passage length because of the continuous ejection of fluid through a series of 19 transfer holes to the plenum. The smooth passage surface opposite is in closest proximity to the external surface, and this investigation has characterised the heat transfer coefficient on this surface at a range of engine representative inlet Reynolds numbers using a hybrid transient liquid crystal technique. The ability of three different rib configurations to enhance the heat transfer on this surface was also determined. Because the passage at engine scale is necessarily small, the rib height in all cases was 32.5% of the passage height. As the entire passage wetted surface is able to contribute to the blade cooling, and knowledge of the heat transfer coefficient distribution on the holed surfaces is crucial to prediction of blade life, a commercial CFD package, Fluent, was used to predict the heat transfer coefficient distributions on the holed surface, where there was no optical access during these tests. This also allowed investigation of additional rib configurations, and comparison of the pressure penalty associated with each design. The study showed that the turbulator configuration used allows the position and maximum level of heat transfer coefficient enhancement to be chosen by the engine designer. For the configurations tested heat transfer coefficient enhancement of up to 32% and 51% could be achieved on the holed surface and the ribbed surface respectively. For minimum additional pressure drop 45° ribs should be used.
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McGrath, E. Lee, and James H. Leylek. "Physics of Hot Crossflow Ingestion in Film Cooling." In ASME 1998 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/98-gt-191.

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Computational fluid dynamics (CFD) is used to isolate the flow physics responsible for hot crossflow ingestion, a phenomenon that can cause failure of a film cooled gas turbine component. In the gas turbine industry, new compound-angle shaped hole (CASH) geometries are currently being developed to decrease the heat transfer coefficient and increase the adiabatic effectiveness on film cooled surfaces. These new CASH geometries can have unexpected flow patterns that result in hot crossflow ingestion at the film hole. This investigation examines a 15° forward-diffused cylindrical film hole injected streamwise at 35° with a compound angle of 60° (FDIFF60) and with a length-to-diameter ratio (L/D) of 4.0. Qualitative and quantitative aspects of computed results agreed well with measurements, thus lending credibility to predictions. The FDIFF60 configuration is a good representative of a typical CASH geometry, and produces flow mechanisms that are characteristic of CASH film cooling. FDIFF60 has been shown to have impressive downstream film cooling performance, while simultaneously having undesirable ingestion at the film hole. In addition to identifying the physical mechanisms driving ingestion, this paper documents the effects on ingestion of the blowing ratio, the density ratio, and the film hole Reynolds number over realistic gas turbine ranges of 0.5 to 1.88, 1.6 to 2.0, and 17,350 to 70,000, respectively. The results of this study show that hot crossflow ingestion is caused by a combination of coolant blockage at the film hole exit plane and of crossflow boundary layer vorticity that has been re-oriented streamwise by the presence of jetting coolant: Ingestion results when this re-oriented vorticity passes over the blocked region of the film hole. The density ratio and the film hole Reynolds number do not have a significant effect on ingestion over the ranges studied, but the blowing ratio has a surprising non-linear effect. Another important result of this study is that the blockage of coolant hampers convection and allows diffusion to transfer heat into the film hole even when ingestion is not present. This produces both an undesirable temperature gradient and high temperature level on the film hole wall itself. Lessons learned about the physics of ingestion are generalized to arbitrary CASH configurations. The systematic computational methodology currently used has been previously documented and has become a standard for ensuring accurate results. The methodology includes exact modeling of flow physics, proper modeling of the geometry including the crossflow, plenum, and film hole regions, a high quality mesh for grid independent results, second order discretization, and the two-equation k-ε turbulence model with generalized wall functions. The steady, Reynolds-averaged Navier-Stokes equations are solved using a fully-elliptical and fully-implicit pressure-correction solver with multi-block unstructured and adaptive grid capability and with multi-grid convergence acceleration.
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Reports on the topic "Plexus blockade"

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Cai, Hai, Xing Fan, Pengjiu Feng, Xiaogang Wang, and Yubo Xie. Optimal Dose of Perineural Dexmedetomidine to Prolong Analgesia After Brachial Plexus Blockade: A Systematic Review and Meta-Analysis of 57 Randomized Clinical Trials. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, January 2021. http://dx.doi.org/10.37766/inplasy2021.1.0066.

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