{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,14]],"date-time":"2026-10-14T07:25:53Z","timestamp":1791962753987,"version":"4.3.4"},"reference-count":12,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2020,8,20]],"date-time":"2020-08-20T00:00:00Z","timestamp":1597881600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2020,8,20]],"date-time":"2020-08-20T00:00:00Z","timestamp":1597881600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Cardiovasc Ultrasound"],"published-print":{"date-parts":[[2020,12]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec>\n<jats:title>Background<\/jats:title>\n<jats:p>Point-of-care transthoracic echocardiography (POC-TTE) is essential in shock management, allowing for stroke volume (SV) and cardiac output (CO) estimation using left ventricular outflow tract diameter (LVOTD) and left ventricular velocity time integral (VTI). Since LVOTD is difficult to obtain and error-prone, the body surface area (BSA) or a modified BSA (mBSA) is sometimes used as a surrogate (LVOTD<jats:sup>BSA<\/jats:sup>, LVOTD<jats:sup>mBSA<\/jats:sup>). Currently, no models of LVOTD based on patient characteristics exist nor have BSA-based alternatives been validated.<\/jats:p>\n<\/jats:sec><jats:sec>\n<jats:title>Methods<\/jats:title>\n<jats:p>Focused rapid echocardiographic evaluations (FREEs) performed in intensive care unit patients over a 3-year period were reviewed. The age, sex, height, and weight were recorded. Human expert measurement of LVOTD (LVOTD<jats:sup>HEM<\/jats:sup>) was performed. An epsilon-support vector regression was used to derive a computer model of the predicted LVOTD (LVOTD<jats:sup>CM<\/jats:sup>). Training, testing, and validation were completed. Pearson coefficient and Bland-Altman were used to assess correlation and agreement.<\/jats:p>\n<\/jats:sec><jats:sec>\n<jats:title>Results<\/jats:title>\n<jats:p>Two hundred eighty-seven TTEs with ideal images of the LVOT were identified. LVOTD<jats:sup>CM<\/jats:sup> was the best method of SV measurement, with a correlation of 0.87. LVOTD<jats:sup>mBSA<\/jats:sup> and LVOTD<jats:sup>BSA<\/jats:sup> had correlations of 0.71 and 0.49 respectively. Root mean square error for LVOTD<jats:sup>CM<\/jats:sup>, LVOTD<jats:sup>mBSA<\/jats:sup>, and LVOTD<jats:sup>BSA<\/jats:sup> respectively were 13.3, 37.0, and 26.4. Bland-Altman for LVOTD<jats:sup>CM<\/jats:sup> demonstrated a bias of 5.2. LVOTD<jats:sup>CM<\/jats:sup> model was used in a separate validation set of 116 ideal images yielding a linear correlation of 0.83 between SV<jats:sup>HEM<\/jats:sup> and SV<jats:sup>CM<\/jats:sup>. Bland Altman analysis for SV<jats:sup>CM<\/jats:sup> had a bias of 2.3 with limits of agreement (LOAs) of \u2212\u200924 and 29, a percent error (PE) of 34% and a root mean square error (RMSE) of 13.9.<\/jats:p>\n<\/jats:sec><jats:sec>\n<jats:title>Conclusions<\/jats:title>\n<jats:p>A computer model may allow for SV and CO measurement when the LVOTD cannot be assessed. Further study is needed to assess the accuracy of the model in various patient populations and in comparison to the gold standard pulmonary artery catheter. The LVOTD<jats:sup>CM<\/jats:sup> is more accurate with less error compared to BSA-based methods, however there is still a percentage error of 33%. BSA should not be used as a surrogate measure of LVOTD. Once validated and improved this model may improve feasibility and allow hemodynamic monitoring via POC-TTE once it is validated.<\/jats:p>\n<\/jats:sec>","DOI":"10.1186\/s12947-020-00219-w","type":"journal-article","created":{"date-parts":[[2020,8,20]],"date-time":"2020-08-20T17:02:53Z","timestamp":1597942973000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["A novel method of calculating stroke volume using point-of-care echocardiography"],"prefix":"10.1186","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9584-0579","authenticated-orcid":false,"given":"Ehson","family":"Aligholizadeh","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"William","family":"Teeter","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rajan","family":"Patel","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peter","family":"Hu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Syeda","family":"Fatima","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shiming","family":"Yang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gautam","family":"Ramani","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sami","family":"Safadi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peter","family":"Olivieri","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Thomas","family":"Scalea","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sarah","family":"Murthi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2020,8,20]]},"reference":[{"key":"219_CR1","doi-asserted-by":"publisher","first-page":"224","DOI":"10.1186\/s13054-015-0932-7","volume":"19","author":"JL Vincent","year":"2015","unstructured":"Vincent JL, Pelosi P, Pearse R, et al. Perioperative cardiovascular monitoring of high-risk patients: a consensus of 12. Crit Care. 2015;19:224.","journal-title":"Crit Care"},{"key":"219_CR2","doi-asserted-by":"publisher","first-page":"1647","DOI":"10.1378\/chest.100.6.1647","volume":"100","author":"KH Komadina","year":"1991","unstructured":"Komadina KH, Schenk DA, LaVeau P, Duncan CA, Chambers SL. Interobserver variability in the interpretation of pulmonary artery catheter pressure tracings. Chest. 1991;100:1647\u201354.","journal-title":"Chest"},{"key":"219_CR3","doi-asserted-by":"publisher","first-page":"5","DOI":"10.1056\/NEJMoa021108","volume":"348","author":"JD Sandham","year":"2003","unstructured":"Sandham JD, Hull RD, Brant RF, et al. A randomized, controlled trial of the use of pulmonary-artery catheters in high-risk surgical patients. N Engl J Med. 2003;348:5\u201314.","journal-title":"N Engl J Med"},{"key":"219_CR4","doi-asserted-by":"publisher","first-page":"1158","DOI":"10.1097\/TA.0b013e31824d1112","volume":"72","author":"SB Murthi","year":"2012","unstructured":"Murthi SB, Hess JR, Hess A, Stansbury LG, Scalea TM. Focused rapid echocardiographic evaluation versus vascular cather-based assessment of cardiac output and function in critically ill trauma patients. J Trauma Acute Care Surg. 2012;72:1158\u201364.","journal-title":"J Trauma Acute Care Surg"},{"key":"219_CR5","doi-asserted-by":"publisher","first-page":"74","DOI":"10.7205\/MILMED-D-14-00374","volume":"180","author":"SB Murthi","year":"2015","unstructured":"Murthi SB, Markandaya M, Fang R, et al. Focused comprehensive, quantitative, functionally based echocardiographic evaluation in the critical care unit is feasible and impacts care. Mil Med. 2015;180:74\u20139.","journal-title":"Mil Med"},{"key":"219_CR6","doi-asserted-by":"publisher","first-page":"505","DOI":"10.1097\/TA.0000000000001331","volume":"82","author":"SB Murthi","year":"2017","unstructured":"Murthi SB, Fatima S, Menne AR, et al. Ultrasound assessment of volume responsiveness in critically ill surgical patients: two measurements are better than one. J Trauma Acute Care Surg. 2017;82:505\u201311.","journal-title":"J Trauma Acute Care Surg"},{"key":"219_CR7","doi-asserted-by":"publisher","first-page":"379","DOI":"10.1097\/TA.0000000000002304","volume":"87","author":"PP Olivieri","year":"2019","unstructured":"Olivieri PP, Patel R, Kolb S, et al. Echo is a good, not perfect, measure of cardiac output in critically ill surgical patients. J Trauma Acute Care Surg. 2019;87:379\u201385.","journal-title":"J Trauma Acute Care Surg"},{"key":"219_CR8","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-540-87956-5","volume-title":"Hemodynamic monitoring using echocardiography in the critically ill","author":"D de Backer","year":"2011","unstructured":"de Backer D, Cholley BP, Slama M, Vieillard-Baron A, Vignon P. Hemodynamic monitoring using echocardiography in the critically ill. Heidelberg: Springer; 2011."},{"key":"219_CR9","doi-asserted-by":"publisher","first-page":"1783","DOI":"10.1016\/S0735-1097(16)31784-3","volume":"67","author":"E Eisenberg","year":"2016","unstructured":"Eisenberg E, Vlismas P, Spinetto P, Spevack D. Sustitution of left ventricular outflow tract diameter with body surface area. JACC. 2016;67:1783.","journal-title":"JACC"},{"key":"219_CR10","unstructured":"Pedregosa F, Varoquaux G, Gramfort A, Michel V, Thirion B, Grisel O, et al. Scikit-learn: Machine learning in Python. J Mach Learn Res. 2011;12:2825\u201330."},{"key":"219_CR11","doi-asserted-by":"publisher","first-page":"157","DOI":"10.1016\/j.jchf.2016.10.011","volume":"5","author":"MM Fernandes-Silva","year":"2017","unstructured":"Fernandes-Silva MM, Shah AM, Hegde S, et al. Race-related differences in left ventricular structural and functional remodeling in response to increased afterload: the ARIC study. JACC Heart Fail. 2017;5:157\u201365.","journal-title":"JACC Heart Fail"},{"key":"219_CR12","doi-asserted-by":"publisher","first-page":"680","DOI":"10.1093\/ehjci\/jet284","volume":"15","author":"S Kou","year":"2014","unstructured":"Kou S, Caballero L, Dulgheru R, et al. Echocardiographic reference ranges for normal cardiac chamber size: results from the NORRE study. Eur Heart J Cardiovasc Imaging. 2014;15:680\u201390.","journal-title":"Eur Heart J Cardiovasc Imaging"}],"container-title":["Cardiovascular Ultrasound"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/link.springer.com\/content\/pdf\/10.1186\/s12947-020-00219-w.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/link.springer.com\/article\/10.1186\/s12947-020-00219-w\/fulltext.html","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/link.springer.com\/content\/pdf\/10.1186\/s12947-020-00219-w.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,8,19]],"date-time":"2021-08-19T23:16:40Z","timestamp":1629415000000},"score":1,"resource":{"primary":{"URL":"https:\/\/cardiovascularultrasound.biomedcentral.com\/articles\/10.1186\/s12947-020-00219-w"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,8,20]]},"references-count":12,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2020,12]]}},"alternative-id":["219"],"URL":"https:\/\/doi.org\/10.1186\/s12947-020-00219-w","relation":{},"ISSN":["1476-7120"],"issn-type":[{"value":"1476-7120","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,8,20]]},"assertion":[{"value":"17 May 2020","order":1,"name":"received","label":"Received","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"10 August 2020","order":2,"name":"accepted","label":"Accepted","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"20 August 2020","order":3,"name":"first_online","label":"First Online","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"This study was approved by University of Maryland Medical System\u2019s institutional review board.","order":1,"name":"Ethics","group":{"name":"EthicsHeading","label":"Ethics approval and consent to participate"}},{"value":"Not applicable.","order":2,"name":"Ethics","group":{"name":"EthicsHeading","label":"Consent for publication"}},{"value":"The authors have no conflicts of interests.","order":3,"name":"Ethics","group":{"name":"EthicsHeading","label":"Competing interests"}}],"article-number":"37"}}