{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T18:18:43Z","timestamp":1787854723248,"version":"build-2784847793"},"reference-count":19,"publisher":"Public Library of Science (PLoS)","issue":"8","license":[{"start":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T00:00:00Z","timestamp":1787788800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS One"],"abstract":"<jats:sec id=\"sec001\">\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Accurate assessment of intravascular volume status in hypernatremic patients presenting to the emergency department is often challenging due to advanced age, altered mental status, and unreliable physical examination. Bedside ultrasonography may provide rapid, noninvasive support for early volume evaluation. This study aimed to assess the clinical utility of inferior vena cava (IVC) diameter and the IVC-to-aorta (IVC\/Ao) ratio in relation to early sodium response in patients with hypernatremia.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sec002\">\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      This prospective observational study included 60 adult patients with hypernatremia presenting to a tertiary emergency department. Ultrasonographic measurements (IVC diameter, aortic diameter, and IVC\/Ao ratio) and manometric measurements (central and peripheral venous pressures) were obtained before fluid resuscitation and repeated at the third hour of treatment. Early sodium response was exploratorily assessed using the 3-hour change in serum sodium (\u0394Na\n                      <jats:sub>1<\/jats:sub>\n                      ). Receiver operating characteristic analysis was used to determine the optimal \u0394Na\n                      <jats:sub>1<\/jats:sub>\n                      cut-off associated with 30-day mortality.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sec003\">\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Patients without early sodium response (n\u2009=\u200942) had significantly higher baseline IVC\/Ao ratios than patients with early sodium response (0.74 vs. 0.50, p\u2009=\u20090.037). Ultrasonographic parameters, including baseline and 3-hour IVC diameter and IVC\/Ao ratio, demonstrated moderate discriminative performance for predicting early sodium response (AUC range: 0.671\u20130.683), whereas manometric measurements did not significantly differ between groups. These indices demonstrated high sensitivity but modest specificity for early sodium response.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sec004\">\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>In hypernatremic patients, bedside ultrasound assessment of IVC diameter and IVC\/Ao ratio may provide rapid, complementary physiologic information during early volume evaluation. These measurements should be interpreted alongside clinical and laboratory findings rather than as standalone indicators of treatment success.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1371\/journal.pone.0356486","type":"journal-article","created":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T17:27:25Z","timestamp":1787851645000},"page":"e0356486","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":0,"title":["Clinical value of the caval\u2013aortic index and inferior vena cava diameter for volume assessment in hypernatremic patients"],"prefix":"10.1371","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7329-1513","authenticated-orcid":true,"given":"Tuba","family":"\u015eafak","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3618-6252","authenticated-orcid":true,"given":"Ahmet Burak","family":"Erdem","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2026,8,27]]},"reference":[{"key":"pone.0356486.ref001","doi-asserted-by":"crossref","first-page":"1493","DOI":"10.1056\/NEJM200005183422006","article-title":"Hypernatremia","volume":"342","author":"HJ Adrogu\u00e9","year":"2000","journal-title":"N Engl J Med"},{"issue":"2","key":"pone.0356486.ref002","doi-asserted-by":"crossref","first-page":"102","DOI":"10.1053\/j.akdh.2022.12.010","article-title":"Salt and water: a review of hypernatremia","volume":"30","author":"N Patel","year":"2023","journal-title":"Adv Kidney Dis Health"},{"issue":"5","key":"pone.0356486.ref003","doi-asserted-by":"crossref","first-page":"656","DOI":"10.2215\/CJN.10640918","article-title":"Rate of correction of hypernatremia and health outcomes in critically ill patients","volume":"14","author":"K Chauhan","year":"2019","journal-title":"Clin J Am Soc Nephrol"},{"issue":"1","key":"pone.0356486.ref004","doi-asserted-by":"crossref","first-page":"55","DOI":"10.1056\/NEJMra1404489","article-title":"Disorders of plasma sodium--causes, consequences, and correction","volume":"372","author":"RH Sterns","year":"2015","journal-title":"N Engl J Med"},{"issue":"7","key":"pone.0356486.ref005","doi-asserted-by":"crossref","first-page":"1774","DOI":"10.1097\/CCM.0b013e31828a25fd","article-title":"Does the central venous pressure predict fluid responsiveness? An updated meta-analysis and a plea for some common sense","volume":"41","author":"PE Marik","year":"2013","journal-title":"Crit Care Med"},{"issue":"3","key":"pone.0356486.ref006","doi-asserted-by":"crossref","first-page":"290","DOI":"10.1016\/j.annemergmed.2009.04.021","article-title":"Emergency department bedside ultrasonographic measurement of the caval index for noninvasive determination of low central venous pressure","volume":"55","author":"AD Nagdev","year":"2010","journal-title":"Ann Emerg Med"},{"key":"pone.0356486.ref007","doi-asserted-by":"crossref","first-page":"43","DOI":"10.2147\/IJNRD.S488639","article-title":"Correlation between the inferior vena cava\/aorta (Ivc\/Ao) ratio and serum lactate levels in children with renal disorder","volume":"18","author":"DDL Hakim","year":"2025","journal-title":"Int J Nephrol Renovasc Dis"},{"issue":"5","key":"pone.0356486.ref008","doi-asserted-by":"crossref","first-page":"552","DOI":"10.1111\/aas.12490","article-title":"Central venous pressure: we need to bring clinical use into physiological context","volume":"59","author":"S Sondergaard","year":"2015","journal-title":"Acta Anaesthesiol Scand"},{"issue":"2","key":"pone.0356486.ref009","doi-asserted-by":"crossref","first-page":"231","DOI":"10.1002\/jum.15093","article-title":"Effect of changes in intravascular volume on inferior vena cava and aorta diameters and the caval\/aorta index in healthy volunteers","volume":"39","author":"S Bilgin","year":"2020","journal-title":"J Ultrasound Med"},{"key":"pone.0356486.ref010","doi-asserted-by":"crossref","first-page":"762437","DOI":"10.3389\/fphys.2021.762437","article-title":"Vascular stiffness in aging and disease","volume":"12","author":"SF Vatner","year":"2021","journal-title":"Front Physiol"},{"issue":"3","key":"pone.0356486.ref011","doi-asserted-by":"crossref","first-page":"306","DOI":"10.2215\/CJN.0000000000000077","article-title":"Correcting hypernatremia in children","volume":"18","author":"M Didsbury","year":"2023","journal-title":"Clin J Am Soc Nephrol"},{"issue":"4","key":"pone.0356486.ref012","doi-asserted-by":"crossref","first-page":"211","DOI":"10.4103\/JETS.JETS_154_20","article-title":"Inferior vena cava\/abdominal aorta ratio as a guide for fluid resuscitation","volume":"14","author":"NP Kusumastuti","year":"2021","journal-title":"J Emerg Trauma Shock"},{"issue":"11","key":"pone.0356486.ref013","doi-asserted-by":"crossref","first-page":"477","DOI":"10.3345\/cep.2022.01445","article-title":"Inferior vena cava to aorta ratio in dehydrated pediatric patients: a systematic review and meta-analysis","volume":"66","author":"GS Octavius","year":"2023","journal-title":"Clin Exp Pediatr"},{"key":"pone.0356486.ref014","doi-asserted-by":"crossref","first-page":"1147","DOI":"10.1080\/13102818.2021.1960190","article-title":"Prediction of fluid responsiveness: a review","volume":"35","author":"R Enev","year":"2021","journal-title":"Biotechnol Biotechnol Equip"},{"issue":"11","key":"pone.0356486.ref015","doi-asserted-by":"crossref","first-page":"648","DOI":"10.4103\/0972-5229.169338","article-title":"Correlation between central venous pressure and peripheral venous pressure with passive leg raise in patients on mechanical ventilation","volume":"19","author":"D Kumar","year":"2015","journal-title":"Indian J Crit Care Med"},{"key":"pone.0356486.ref016","doi-asserted-by":"crossref","first-page":"80","DOI":"10.1016\/j.amjcard.2020.09.055","article-title":"Relation of peripheral venous pressure to central venous pressure in patients with heart failure, heart transplant, and left ventricular assist device","volume":"138","author":"PP Vlismas","year":"2021","journal-title":"Am J Cardiol"},{"issue":"12","key":"pone.0356486.ref017","doi-asserted-by":"crossref","first-page":"1298","DOI":"10.1001\/jama.2016.12310","article-title":"Will this hemodynamically unstable patient respond to a bolus of intravenous fluids?","volume":"316","author":"P Bentzer","year":"2016","journal-title":"JAMA"},{"issue":"9","key":"pone.0356486.ref018","doi-asserted-by":"crossref","DOI":"10.1001\/jamanetworkopen.2023.35415","article-title":"Rate of correction and all-cause mortality in patients with severe hypernatremia","volume":"6","author":"E Feigin","year":"2023","journal-title":"JAMA Netw Open"},{"issue":"11","key":"pone.0356486.ref019","doi-asserted-by":"crossref","first-page":"3501","DOI":"10.1093\/ndt\/gfn476","article-title":"Can we really predict the change in serum sodium levels? 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