{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,5,14]],"date-time":"2025-05-14T00:31:46Z","timestamp":1747182706365,"version":"3.40.5"},"reference-count":16,"publisher":"Wiley","issue":"7","license":[{"start":{"date-parts":[[2023,6,24]],"date-time":"2023-06-24T00:00:00Z","timestamp":1687564800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001858","name":"VINNOVA","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100001858","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Acta Anaesthesiol Scand"],"published-print":{"date-parts":[[2023,8]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Background<\/jats:title><jats:p>Patients with Covid\u201019 respiratory failure present with hypoxemia, often in combination with hypercapnia. In this prospective, observational study we examined the effect of removing external dead space (DS) on CO<jats:sub>2<\/jats:sub>\u2010homeostasis in mechanically ventilated Covid\u201019 patients. In addition, volumetric capnography was validated for its ability to estimate external DS volume using in vitro measured DS volumes as reference.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>In total, 10 patients with acute respiratory distress syndrome from Covid\u201019 were included. Volumetric capnography, mechanical ventilation, and arterial blood gas data were analyzed before and after removal of external DS and analyzed for potentially significant changes in response to DS removal. Measurements of external DS were obtained in circuit using volumetric capnography and compared to actual measured DS volumes off the circuit.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>After the removal of external DS, the alveolar minute ventilation and CO<jats:sub>2<\/jats:sub> elimination improved, notwithstanding unchanged respiratory rate and tidal volumes. The increase in CO<jats:sub>2<\/jats:sub> elimination was associated with a decrease in arterial CO<jats:sub>2<\/jats:sub> partial pressure (PaCO<jats:sub>2<\/jats:sub>)<jats:sub>.<\/jats:sub> The volumetric capnography method for assessment of external DS showed a low bias of \u22129\u2009mL (lower limit of agreement \u221240, 95% CI \u221260 to \u221220\u2009mL, upper limit of agreement 21\u2009mL, 95% CI: 1\u201340\u2009mL) and a percentage error of 48% compared to absolute values measured in vitro.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>Removal of external DS increased alveolar minute ventilation and CO<jats:sub>2<\/jats:sub> elimination in Covid\u201019 patients with respiratory failure in the current study. This was associated with a decrease in PaCO<jats:sub>2<\/jats:sub>. This may indicate a decreased CO<jats:sub>2<\/jats:sub> production due to decreased work of breathing and more effective gas\u2010exchange in response to DS removal. In addition, volumetric capnography appears to be a clinically feasible method for continuous measurement of external DS in the current study and may be of value in optimizing ventilator treatment.<\/jats:p><\/jats:sec>","DOI":"10.1111\/aas.14252","type":"journal-article","created":{"date-parts":[[2023,6,25]],"date-time":"2023-06-25T01:45:16Z","timestamp":1687657516000},"page":"936-942","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Effect of external dead space removal on <scp>CO<sub>2<\/sub><\/scp> homeostasis in mechanically ventilated adult Covid\u201019 patients"],"prefix":"10.1111","volume":"67","author":[{"given":"Tomas","family":"\u00d6hman","sequence":"first","affiliation":[{"name":"Department of Perioperative Medicine and Intensive Care Karolinska University Hospital  Stockholm Sweden"},{"name":"Department of Physiology and Pharmacology Karolinska Institutet  Stockholm Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Francesca Campoccia","family":"Jalde","sequence":"additional","affiliation":[{"name":"Department of Thoracic Anesthesiology Surgical Services and Intensive Care, Karolinska University Hospital  Stockholm Sweden"},{"name":"Department of Molecular Medicine and Surgery Karolinska Institutet  Stockholm Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Magnus","family":"Fredby","sequence":"additional","affiliation":[{"name":"Department of Thoracic Anesthesiology Surgical Services and Intensive Care, Karolinska University Hospital  Stockholm Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"H\u00e5kan","family":"Bj\u00f6rne","sequence":"additional","affiliation":[{"name":"Department of Perioperative Medicine and Intensive Care Karolinska University Hospital  Stockholm Sweden"},{"name":"Department of Physiology and Pharmacology Karolinska Institutet  Stockholm 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