{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,20]],"date-time":"2026-04-20T03:42:30Z","timestamp":1776656550896,"version":"3.51.2"},"reference-count":33,"publisher":"Wiley","license":[{"start":{"date-parts":[[2026,4,19]],"date-time":"2026-04-19T00:00:00Z","timestamp":1776556800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"},{"start":{"date-parts":[[2026,4,19]],"date-time":"2026-04-19T00:00:00Z","timestamp":1776556800000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["beva.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Equine Veterinary Journal"],"abstract":"Abstract<\/jats:title>\n \n Background<\/jats:title>\n \n Intraoperative haemorrhage during equine anaesthesia is a rare but potentially fatal complication requiring prompt haemodynamic support. Postural manoeuvres such as\n Trendelenburg<\/jats:italic>\n (TL) positioning and vasopressor support augment venous return and improve cardiac output (CO), yet their efficacy in anaesthetised hypovolemic horses remains unstudied.\n <\/jats:p>\n <\/jats:sec>\n \n Objectives<\/jats:title>\n To evaluate haemodynamic effects of TL positioning during normovolemia and acute haemorrhagic hypovolemia, and to determine whether concurrent norepinephrine (NE) infusion enhances cardiovascular stabilisation.<\/jats:p>\n <\/jats:sec>\n \n Study Design<\/jats:title>\n In vivo experiments.<\/jats:p>\n <\/jats:sec>\n \n Methods<\/jats:title>\n Six dorsally recumbent isoflurane\u2010anaesthetised horses were studied under normovolemia, acute haemorrhage\u2010induced hypovolemia, and hypovolemia with NE infusion. Haemodynamic variables, including CO, mean arterial pressure (MAP), central venous pressure (CVP), systemic vascular resistance (SVR), mean pulmonary arterial pressure (mPAP), and heart rate (HR), were recorded at multiple timepoints before, during, and after TL positioning (30\u00b0 incline). Norepinephrine was administered at 0.1\u2009\u03bcg\/kg\/min to restore MAP above 80\u2009mmHg.<\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n \n Trendelenburg<\/jats:italic>\n positioning during normovolemia resulted in modest, transient increases in CO (~28%), MAP (~22%), CVP, and mPAP (\n p<\/jats:italic>\n \u2009<\u20090.05), with no change in HR and SVR. Haemorrhagic hypovolemia significantly reduced all haemodynamic indices (\n p<\/jats:italic>\n \u2009<\u20090.01) except HR and SVR. TL positioning partially reversed these effects (increase in CO ~40% and MAP ~67%;\n p<\/jats:italic>\n \u2009<\u20090.05). Norepinephrine infusion alone during hypovolemia significantly increased CO, MAP, and SVR, with additional improvement when combined with TL positioning (increase in CO ~75%;\n p<\/jats:italic>\n \u2009<\u20090.05), suggesting enhanced effects.\n <\/jats:p>\n <\/jats:sec>\n \n Main Limitations<\/jats:title>\n Small sample size and use of healthy experimental animals limit translational generalisability of the findings to clinical populations.<\/jats:p>\n <\/jats:sec>\n \n Conclusions<\/jats:title>\n TL positioning transiently improves haemodynamics in anaesthetised horses, with more pronounced benefits during hypovolemia. The addition of NE infusion enhances this effect, supporting their combination as a potential physiologic rescue strategy in hypovolemic equine patients.<\/jats:p>\n <\/jats:sec>","DOI":"10.1002\/evj.70169","type":"journal-article","created":{"date-parts":[[2026,4,20]],"date-time":"2026-04-20T03:06:58Z","timestamp":1776654418000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Trendelenburg<\/i>\n positioning with or without norepinephrine infusion for haemodynamic support in anaesthetised hypovolemic horses"],"prefix":"10.1002","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9751-6825","authenticated-orcid":false,"given":"Vaidehi V.","family":"Paranjape","sequence":"first","affiliation":[{"name":"Department of Small Animal Clinical Sciences Virginia\u2010Maryland College of Veterinary Medicine Blacksburg Virginia USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0329-3083","authenticated-orcid":false,"given":"Klaus","family":"Hopster","sequence":"additional","affiliation":[{"name":"Department of Clinical Studies\u2010New Bolton Center School of Veterinary Medicine, University of Pennsylvania Kennett Square Pennsylvania USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3768-3007","authenticated-orcid":false,"given":"Ismar","family":"Lutvikadic","sequence":"additional","affiliation":[{"name":"Department of Clinical Studies\u2010New Bolton Center School of Veterinary Medicine, University of Pennsylvania Kennett Square Pennsylvania USA"},{"name":"Department of Clinical Science University of Sarajevo\u2014Veterinary Faculty Sarajevo Bosnia and Herzegovina"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5522-6072","authenticated-orcid":false,"given":"Bernd","family":"Driessen","sequence":"additional","affiliation":[{"name":"Department of Clinical Studies\u2010New Bolton Center School of Veterinary Medicine, University of Pennsylvania Kennett Square Pennsylvania USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2026,4,19]]},"reference":[{"issue":"1","key":"e_1_2_13_2_1","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1111\/vec.13122","article-title":"The pathophysiology of uncontrolled hemorrhage in horses","volume":"32","author":"Hurcombe SDA","year":"2022","journal-title":"J Vet Emerg Crit Care (San Antonio)"},{"issue":"3","key":"e_1_2_13_3_1","doi-asserted-by":"crossref","first-page":"208","DOI":"10.1111\/j.2042-3306.1999.tb03174.x","article-title":"An evaluation of the haemostatic suture in hysterotomy closure in the mare","volume":"31","author":"Freeman DE","year":"1999","journal-title":"Equine Vet J"},{"issue":"6","key":"e_1_2_13_4_1","doi-asserted-by":"crossref","first-page":"553","DOI":"10.1111\/j.1532-950X.2003.00553.x","article-title":"Life\u2010threatening hemorrhage from enterotomies and anastomoses in 7 horses","volume":"32","author":"Doyle AJ","year":"2003","journal-title":"Vet Surg"},{"issue":"3","key":"e_1_2_13_5_1","doi-asserted-by":"crossref","first-page":"203","DOI":"10.1080\/00480169.2011.648891","article-title":"Guttural pouch mycosis in six horses in New Zealand","volume":"60","author":"Archer RM","year":"2012","journal-title":"N Z Vet J"},{"key":"e_1_2_13_6_1","doi-asserted-by":"crossref","first-page":"557","DOI":"10.1016\/B978-1-4377-0867-7.00043-0","volume-title":"Equine surgery","author":"Nickels FA","year":"2012"},{"issue":"1","key":"e_1_2_13_7_1","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1111\/vec.13126","article-title":"Pathophysiology of hemorrhagic shock","volume":"32","author":"Kuo K","year":"2022","journal-title":"J Vet Emerg Crit Care (San Antonio)"},{"issue":"4","key":"e_1_2_13_8_1","doi-asserted-by":"crossref","first-page":"273","DOI":"10.1111\/j.2042-3306.1990.tb04266.x","article-title":"Haemodynamic effects of small volume hypertonic saline in experimentally induced haemorrhagic shock","volume":"22","author":"Schmall LM","year":"1990","journal-title":"Equine Vet J"},{"issue":"1","key":"e_1_2_13_9_1","doi-asserted-by":"crossref","DOI":"10.1186\/s13613-022-01022-8","article-title":"Prediction of fluid responsiveness. 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