Editing Cardiac output (section)

====Transoesophageal====
[[File:TEE-Sonde.png|alt=A Transesophageal echocardiogram (BrE: TOE, AmE: TEE) probe.|thumb|A transoesophageal echocardiogram probe.]]

The Transoesophageal Doppler includes two main technologies; [[Transesophageal echocardiogram|transoesophageal echocardiogram]]—which is primarily used for diagnostic purposes, and [[Esophogeal doppler|oesophageal Doppler]] monitoring—which is primarily used for the clinical monitoring of cardiac output. The latter uses continuous wave Doppler to measure blood velocity in the [[descending aorta|descending thoracic aorta]]. An ultrasound probe is inserted either orally or nasally into the oesophagus to mid-thoracic level, at which point the oesophagus lies alongside the descending [[thoracic aorta]]. Because the transducer is close to the blood flow, the signal is clear. The probe may require re-focussing to ensure an optimal signal. This method has good validation, is widely used for fluid management during surgery with evidence for improved patient outcome,<ref>{{cite journal | vauthors = Mythen MG, Webb AR | title = Perioperative plasma volume expansion reduces the incidence of gut mucosal hypoperfusion during cardiac surgery | journal = Archives of Surgery | volume = 130 | issue = 4 | pages = 423–29 | date = April 1995 | pmid = 7535996 | doi = 10.1001/archsurg.1995.01430040085019 }}</ref><ref>{{cite journal | vauthors = Sinclair S, James S, Singer M | title = Intraoperative intravascular volume optimisation and length of hospital stay after repair of proximal femoral fracture: randomised controlled trial | journal = BMJ | volume = 315 | issue = 7113 | pages = 909–12 | date = October 1997 | pmid = 9361539 | pmc = 2127619 | doi = 10.1136/bmj.315.7113.909 }}</ref><ref>{{cite journal | vauthors = Conway DH, Mayall R, Abdul-Latif MS, Gilligan S, Tackaberry C | title = Randomised controlled trial investigating the influence of intravenous fluid titration using oesophageal Doppler monitoring during bowel surgery | journal = Anaesthesia | volume = 57 | issue = 9 | pages = 845–49 | date = September 2002 | pmid = 12190747 | doi = 10.1046/j.1365-2044.2002.02708.x | s2cid = 43755776 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Gan TJ, Soppitt A, Maroof M, el-Moalem H, Robertson KM, Moretti E, Dwane P, Glass PS | title = Goal-directed intraoperative fluid administration reduces length of hospital stay after major surgery | journal = Anesthesiology | volume = 97 | issue = 4 | pages = 820–26 | date = October 2002 | pmid = 12357146 | doi = 10.1097/00000542-200210000-00012 | s2cid = 10471164 }}</ref><ref>{{cite journal | vauthors = Venn R, Steele A, Richardson P, Poloniecki J, Grounds M, Newman P | title = Randomized controlled trial to investigate influence of the fluid challenge on duration of hospital stay and perioperative morbidity in patients with hip fractures | journal = British Journal of Anaesthesia | volume = 88 | issue = 1 | pages = 65–71 | date = January 2002 | pmid = 11881887 | doi = 10.1093/bja/88.1.65 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Wakeling HG, McFall MR, Jenkins CS, Woods WG, Miles WF, Barclay GR, Fleming SC | title = Intraoperative oesophageal Doppler guided fluid management shortens postoperative hospital stay after major bowel surgery | journal = British Journal of Anaesthesia | volume = 95 | issue = 5 | pages = 634–42 | date = November 2005 | pmid = 16155038 | doi = 10.1093/bja/aei223 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Noblett SE, Snowden CP, Shenton BK, Horgan AF | title = Randomized clinical trial assessing the effect of Doppler-optimized fluid management on outcome after elective colorectal resection | journal = The British Journal of Surgery | volume = 93 | issue = 9 | pages = 1069–76 | date = September 2006 | pmid = 16888706 | doi = 10.1002/bjs.5454 | s2cid = 25469534 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Pillai P, McEleavy I, Gaughan M, Snowden C, Nesbitt I, Durkan G, Johnson M, Cosgrove J, Thorpe A | title = A double-blind randomized controlled clinical trial to assess the effect of Doppler optimized intraoperative fluid management on outcome following radical cystectomy | journal = The Journal of Urology | volume = 186 | issue = 6 | pages = 2201–06 | date = December 2011 | pmid = 22014804 | doi = 10.1016/j.juro.2011.07.093 }}</ref> and has been recommended by the UK's National Institute for Health and Clinical Excellence ([[NICE]]).<ref>{{Cite web|url=https://www.nice.org.uk/mtg3|title=CardioQ-ODM oesophageal doppler monitor &#124; Guidance &#124; NICE|date=25 March 2011 |access-date=23 February 2022|archive-date=23 February 2022|archive-url=https://web.archive.org/web/20220223063027/https://www.nice.org.uk/guidance/mtg3|url-status=live}}</ref> Oesophageal Doppler monitoring measures the velocity of blood and not true ''Q'', therefore relies on a nomogram<ref>{{cite web |first1=Graham D. |last1=Lowe |first2=Barry M. |last2=Chamberlain |first3=Eleanor J. |last3=Philpot |first4=Richard J. |last4=Willshire |name-list-style=vanc |year=2010 |title=Oesophageal Doppler Monitor (ODM) guided individualised goal directed fluid management (iGDFM) in surgery – a technical review |work=Deltex Medical Technical Review |url=https://www.deltexmedical.com/downloads/TechnicalReview.pdf |url-status=dead |archive-url=https://web.archive.org/web/20150923213441/https://www.deltexmedical.com/downloads/TechnicalReview.pdf |archive-date=23 September 2015 |access-date=13 October 2014 }}</ref> based on patient age, height and weight to convert the measured velocity into stroke volume and cardiac output. This method generally requires patient sedation and is accepted for use in both adults and children.{{citation needed|date=March 2021}}