{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,5,14]],"date-time":"2025-05-14T00:31:53Z","timestamp":1747182713875,"version":"3.40.5"},"reference-count":32,"publisher":"Wiley","issue":"2","license":[{"start":{"date-parts":[[2019,10,14]],"date-time":"2019-10-14T00:00:00Z","timestamp":1571011200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Acta Anaesthesiol Scand"],"published-print":{"date-parts":[[2020,2]]},"abstract":"<jats:sec><jats:label\/><jats:sec><jats:title>Background<\/jats:title><jats:p>Venoarterial carbon dioxide pressure (p<jats:sub>v\u2010a<\/jats:sub>CO<jats:sub>2<\/jats:sub>) and content (C<jats:sub>v\u2010a<\/jats:sub>CO<jats:sub>2<\/jats:sub>) differences, including the ratio to arteriovenous oxygen content difference (C<jats:sub>a\u2010v<\/jats:sub>O<jats:sub>2<\/jats:sub>), and free energy changes (\u2212\u2206\u2206G<jats:sub>a\u2010v<\/jats:sub>) may reflect tissue hypoperfusion. The associations with changes in cardiac output (CO) or oxygen consumption (VO<jats:sub>2<\/jats:sub>) following fluid bolus administration were investigated.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Single\u2010centre, observational study of 89 adult post\u2010operative cardiac surgical patients admitted to ICU. The p<jats:sub>v\u2010a<\/jats:sub>CO<jats:sub>2<\/jats:sub>, C<jats:sub>v\u2010a<\/jats:sub>CO<jats:sub>2<\/jats:sub> and their ratios to C<jats:sub>a\u2010v<\/jats:sub>O<jats:sub>2<\/jats:sub> as well as the \u2212\u2206\u2206G<jats:sub>a\u2010v<\/jats:sub> were determined before and after a 250\u2010500\u00a0mL fluid bolus using arterial, central venous and mixed venous blood gas analyses. Responses associated with changes \u2265 or &lt;15% in CO or oxygen consumption (VO<jats:sub>2<\/jats:sub>) were compared.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>In 234 boluses, the mixed venous to arterial p<jats:sub>v\u2010a<\/jats:sub>CO<jats:sub>2<\/jats:sub> and its ratio to C<jats:sub>a\u2010v<\/jats:sub>O<jats:sub>2<\/jats:sub> were independently associated with an increase in CO; odds ratio 1.3 (95% CI 1.1\u20101.5) and 1.7 (95% CI 1.5\u20101.9) respectively, <jats:italic>P<\/jats:italic>\u00a0&lt;\u00a0.001) and VO<jats:sub>2<\/jats:sub>; odds ratio 2.1 (95% CI 1.3\u20103.1), <jats:italic>P<\/jats:italic>\u00a0&lt;\u00a0.001 for C<jats:sub>a\u2010v<\/jats:sub>O<jats:sub>2<\/jats:sub>. No measures of p<jats:sub>v\u2010a<\/jats:sub>CO<jats:sub>2<\/jats:sub>, C<jats:sub>v\u2010a<\/jats:sub>CO<jats:sub>2<\/jats:sub> or related ratios to the C<jats:sub>a\u2010v<\/jats:sub>O<jats:sub>2<\/jats:sub> were associated with an increase in CO \u226515% following a single volume bolus. The mixed venous and central venous C<jats:sub>v\u2010a<\/jats:sub>CO<jats:sub>2<\/jats:sub> to C<jats:sub>a\u2010v<\/jats:sub>O<jats:sub>2<\/jats:sub> ratios were different for the first bolus episode only; mean differences 0.81 (95% CI 0.13\u20101.5), <jats:italic>P<\/jats:italic>\u00a0=\u00a0.02 and 0.44 (95% CI 0.06\u20100.82), <jats:italic>P<\/jats:italic>\u00a0=\u00a0.02, respectively, for increased VO<jats:sub>2<\/jats:sub>\u00a0\u2265\u00a015%. The \u2212\u2206\u2206G<jats:sub>a\u2010v<\/jats:sub> did not change.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>The venoarterial carbon dioxide gradients and related calculations to assess the adequacy of tissue perfusion before a fluid bolus were not associated with subsequent increases in CO of oxygen consumption.<\/jats:p><\/jats:sec><\/jats:sec><jats:sec><jats:label\/><jats:p>\n<jats:boxed-text content-type=\"box\" position=\"anchor\"><jats:caption><jats:title>Editorial Comment<\/jats:title><\/jats:caption><jats:p>In some shock conditions, regional tissue hypoperfusion can be obvious and arterio\u2010venous differences for CO<jats:sub>2<\/jats:sub> or O<jats:sub>2<\/jats:sub> may reflect this. This is not always the case; sometimes there are A\u2010V differences or even a high lactate level without any obvious regional tissue hypoperfusion. Fluid therapy is a cornerstone in shock resuscitation treatment, but determining optimal fluid therapy is challenging, particularly as fluid overload may be detrimental. Fluid challenges are used as an \u201cex juvantebus\u201d method to dose fluid therapy, but it is not clear if a positive response reflects a state of hypoperfusion or the existence of a cardiac reserve. Still, a better understanding on how to target and guide fluid therapy is welcome, and studies digging into the problem are needed. Here, invasively monitored post\u2010operative cardiac surgery patients are assessed as a model to investigate if carbon dioxide gaps and free energy charge may be useful in detecting possible tissue hypoperfusion.<\/jats:p><\/jats:boxed-text>\n<\/jats:p><\/jats:sec>","DOI":"10.1111\/aas.13480","type":"journal-article","created":{"date-parts":[[2019,9,23]],"date-time":"2019-09-23T13:26:30Z","timestamp":1569245190000},"page":"202-210","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Prospective, observational study of carbon dioxide gaps and free energy change and their association with fluid therapy following cardiac surgery"],"prefix":"10.1111","volume":"64","author":[{"given":"Sajeev","family":"Mahendran","sequence":"first","affiliation":[{"name":"Faculty of Medicine University of New South Wales Sydney Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"John","family":"Nguyen","sequence":"additional","affiliation":[{"name":"Faculty of Medicine University of New South Wales Sydney Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0989-2100","authenticated-orcid":false,"given":"Ethan","family":"Butler","sequence":"additional","affiliation":[{"name":"Faculty of Medicine University of New South Wales Sydney Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2096-5304","authenticated-orcid":false,"given":"Anders","family":"Aneman","sequence":"additional","affiliation":[{"name":"Intensive Care Unit Liverpool Hospital South Western Sydney Local Health District Sydney Australia"},{"name":"South Western Sydney Clinical School University of New South Wales Sydney Australia"},{"name":"Faculty of Medicine and Health Sciences Macquarie University Sydney Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2019,10,14]]},"reference":[{"issue":"531","key":"e_1_2_7_2_1","first-page":"e1","article-title":"Discordance between microcirculatory alterations and arterial pressure in patients with hemodynamic instability","volume":"27","author":"Arnold RC","year":"2012","journal-title":"J Crit Care"},{"key":"e_1_2_7_3_1","doi-asserted-by":"publisher","DOI":"10.1186\/cc14726"},{"key":"e_1_2_7_4_1","doi-asserted-by":"publisher","DOI":"10.1053\/j.jvca.2011.07.021"},{"key":"e_1_2_7_5_1","doi-asserted-by":"publisher","DOI":"10.1097\/01.sla.0000164173.05762.32"},{"key":"e_1_2_7_6_1","doi-asserted-by":"publisher","DOI":"10.1007\/s00134-015-3850-x"},{"key":"e_1_2_7_7_1","doi-asserted-by":"publisher","DOI":"10.1097\/CCM.0000000000001479"},{"key":"e_1_2_7_8_1","doi-asserted-by":"publisher","DOI":"10.1093\/bja\/aet020"},{"key":"e_1_2_7_9_1","doi-asserted-by":"publisher","DOI":"10.1186\/cc9310"},{"key":"e_1_2_7_10_1","doi-asserted-by":"publisher","DOI":"10.1186\/s13054-015-0917-6"},{"key":"e_1_2_7_11_1","doi-asserted-by":"publisher","DOI":"10.1177\/0310057X1504300512"},{"key":"e_1_2_7_12_1","doi-asserted-by":"publisher","DOI":"10.1097\/MCC.0000000000000493"},{"key":"e_1_2_7_13_1","doi-asserted-by":"publisher","DOI":"10.1007\/s00134-016-4233-7"},{"key":"e_1_2_7_14_1","doi-asserted-by":"publisher","DOI":"10.1258\/0004563001899096"},{"key":"e_1_2_7_15_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.athoracsur.2006.01.025"},{"key":"e_1_2_7_16_1","doi-asserted-by":"publisher","DOI":"10.1053\/j.jvca.2014.09.006"},{"key":"e_1_2_7_17_1","doi-asserted-by":"publisher","DOI":"10.1053\/j.jvca.2017.02.015"},{"key":"e_1_2_7_18_1","doi-asserted-by":"publisher","DOI":"10.1007\/s10877-016-9855-3"},{"key":"e_1_2_7_19_1","doi-asserted-by":"publisher","DOI":"10.1007\/s10877-018-0137-0"},{"key":"e_1_2_7_20_1","doi-asserted-by":"publisher","DOI":"10.1177\/0267659106074004"},{"key":"e_1_2_7_21_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(07)61602-X"},{"key":"e_1_2_7_22_1","unstructured":"NekicP. 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