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Dynamic blood oxygen indices in mechanically ventilated COVID-19 patients with acute hypoxic respiratory failure: A cohort study

BACKGROUND: Acute hypoxic respiratory failure (AHRF) is a hallmark of severe COVID-19 pneumonia and often requires supplementary oxygen therapy. Critically ill COVID-19 patients may require invasive mechanical ventilation, which carries significant morbidity and mortality. Understanding of the relat...

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Autores principales: Bracegirdle, Luke, Jackson, Alexander, Beecham, Ryan, Burova, Maria, Hunter, Elsie, Hamilton, Laura G., Pandya, Darshni, Morden, Clare, Grocott, Michael P. W., Cumpstey, Andrew, Dushianthan, Ahilanandan
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9187096/
https://www.ncbi.nlm.nih.gov/pubmed/35687543
http://dx.doi.org/10.1371/journal.pone.0269471
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author Bracegirdle, Luke
Jackson, Alexander
Beecham, Ryan
Burova, Maria
Hunter, Elsie
Hamilton, Laura G.
Pandya, Darshni
Morden, Clare
Grocott, Michael P. W.
Cumpstey, Andrew
Dushianthan, Ahilanandan
author_facet Bracegirdle, Luke
Jackson, Alexander
Beecham, Ryan
Burova, Maria
Hunter, Elsie
Hamilton, Laura G.
Pandya, Darshni
Morden, Clare
Grocott, Michael P. W.
Cumpstey, Andrew
Dushianthan, Ahilanandan
author_sort Bracegirdle, Luke
collection PubMed
description BACKGROUND: Acute hypoxic respiratory failure (AHRF) is a hallmark of severe COVID-19 pneumonia and often requires supplementary oxygen therapy. Critically ill COVID-19 patients may require invasive mechanical ventilation, which carries significant morbidity and mortality. Understanding of the relationship between dynamic changes in blood oxygen indices and clinical variables is lacking. We evaluated the changes in blood oxygen indices–PaO(2), PaO(2)/FiO(2) ratio, oxygen content (CaO(2)) and oxygen extraction ratio (O(2)ER) in COVID-19 patients through the first 30-days of intensive care unit admission and explored relationships with clinical outcomes. METHODS AND FINDINGS: We performed a retrospective observational cohort study of all adult COVID-19 patients in a single institution requiring invasive mechanical ventilation between March 2020 and March 2021. We collected baseline characteristics, clinical outcomes and blood oxygen indices. 36,383 blood gas data points were analysed from 184 patients over 30-days. Median participant age was 59.5 (IQR 51.0, 67.0), BMI 30.0 (IQR 25.2, 35.5) and the majority were men (62.5%) of white ethnicity (70.1%). Median duration of mechanical ventilation was 15-days (IQR 8, 25). Hospital survival at 30-days was 72.3%. Non-survivors exhibited significantly lower PaO(2) throughout intensive care unit admission: day one to day 30 averaged mean difference -0.52 kPa (95% CI: -0.59 to -0.46, p<0.01). Non-survivors exhibited a significantly lower PaO(2)/FiO(2) ratio with an increased separation over time: day one to day 30 averaged mean difference -5.64 (95% CI: -5.85 to -5.43, p<0.01). While all patients had sub-physiological CaO(2), non-survivors exhibited significantly higher values. Non-survivors also exhibited significantly lower oxygen extraction ratio with an averaged mean difference of -0.08 (95% CI: -0.09 to -0.07, p<0.01) across day one to day 30. CONCLUSIONS: As a novel cause of acute hypoxic respiratory failure, COVID-19 offers a unique opportunity to study a homogenous cohort of patients with hypoxaemia. In mechanically ventilated adult COVID-19 patients, blood oxygen indices are abnormal with substantial divergence in PaO(2)/FiO(2) ratio and oxygen extraction ratio between survivors and non-survivors. Despite having higher CaO(2) values, non-survivors appear to extract less oxygen implying impaired oxygen utilisation. Further exploratory studies are warranted to evaluate and improve oxygen extraction which may help to improve outcomes in severe hypoxaemic mechanically ventilated COVID-19 patients.
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spelling pubmed-91870962022-06-11 Dynamic blood oxygen indices in mechanically ventilated COVID-19 patients with acute hypoxic respiratory failure: A cohort study Bracegirdle, Luke Jackson, Alexander Beecham, Ryan Burova, Maria Hunter, Elsie Hamilton, Laura G. Pandya, Darshni Morden, Clare Grocott, Michael P. W. Cumpstey, Andrew Dushianthan, Ahilanandan PLoS One Research Article BACKGROUND: Acute hypoxic respiratory failure (AHRF) is a hallmark of severe COVID-19 pneumonia and often requires supplementary oxygen therapy. Critically ill COVID-19 patients may require invasive mechanical ventilation, which carries significant morbidity and mortality. Understanding of the relationship between dynamic changes in blood oxygen indices and clinical variables is lacking. We evaluated the changes in blood oxygen indices–PaO(2), PaO(2)/FiO(2) ratio, oxygen content (CaO(2)) and oxygen extraction ratio (O(2)ER) in COVID-19 patients through the first 30-days of intensive care unit admission and explored relationships with clinical outcomes. METHODS AND FINDINGS: We performed a retrospective observational cohort study of all adult COVID-19 patients in a single institution requiring invasive mechanical ventilation between March 2020 and March 2021. We collected baseline characteristics, clinical outcomes and blood oxygen indices. 36,383 blood gas data points were analysed from 184 patients over 30-days. Median participant age was 59.5 (IQR 51.0, 67.0), BMI 30.0 (IQR 25.2, 35.5) and the majority were men (62.5%) of white ethnicity (70.1%). Median duration of mechanical ventilation was 15-days (IQR 8, 25). Hospital survival at 30-days was 72.3%. Non-survivors exhibited significantly lower PaO(2) throughout intensive care unit admission: day one to day 30 averaged mean difference -0.52 kPa (95% CI: -0.59 to -0.46, p<0.01). Non-survivors exhibited a significantly lower PaO(2)/FiO(2) ratio with an increased separation over time: day one to day 30 averaged mean difference -5.64 (95% CI: -5.85 to -5.43, p<0.01). While all patients had sub-physiological CaO(2), non-survivors exhibited significantly higher values. Non-survivors also exhibited significantly lower oxygen extraction ratio with an averaged mean difference of -0.08 (95% CI: -0.09 to -0.07, p<0.01) across day one to day 30. CONCLUSIONS: As a novel cause of acute hypoxic respiratory failure, COVID-19 offers a unique opportunity to study a homogenous cohort of patients with hypoxaemia. In mechanically ventilated adult COVID-19 patients, blood oxygen indices are abnormal with substantial divergence in PaO(2)/FiO(2) ratio and oxygen extraction ratio between survivors and non-survivors. Despite having higher CaO(2) values, non-survivors appear to extract less oxygen implying impaired oxygen utilisation. Further exploratory studies are warranted to evaluate and improve oxygen extraction which may help to improve outcomes in severe hypoxaemic mechanically ventilated COVID-19 patients. Public Library of Science 2022-06-10 /pmc/articles/PMC9187096/ /pubmed/35687543 http://dx.doi.org/10.1371/journal.pone.0269471 Text en © 2022 Bracegirdle et al https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Bracegirdle, Luke
Jackson, Alexander
Beecham, Ryan
Burova, Maria
Hunter, Elsie
Hamilton, Laura G.
Pandya, Darshni
Morden, Clare
Grocott, Michael P. W.
Cumpstey, Andrew
Dushianthan, Ahilanandan
Dynamic blood oxygen indices in mechanically ventilated COVID-19 patients with acute hypoxic respiratory failure: A cohort study
title Dynamic blood oxygen indices in mechanically ventilated COVID-19 patients with acute hypoxic respiratory failure: A cohort study
title_full Dynamic blood oxygen indices in mechanically ventilated COVID-19 patients with acute hypoxic respiratory failure: A cohort study
title_fullStr Dynamic blood oxygen indices in mechanically ventilated COVID-19 patients with acute hypoxic respiratory failure: A cohort study
title_full_unstemmed Dynamic blood oxygen indices in mechanically ventilated COVID-19 patients with acute hypoxic respiratory failure: A cohort study
title_short Dynamic blood oxygen indices in mechanically ventilated COVID-19 patients with acute hypoxic respiratory failure: A cohort study
title_sort dynamic blood oxygen indices in mechanically ventilated covid-19 patients with acute hypoxic respiratory failure: a cohort study
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9187096/
https://www.ncbi.nlm.nih.gov/pubmed/35687543
http://dx.doi.org/10.1371/journal.pone.0269471
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