{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,1]],"date-time":"2026-02-01T06:07:26Z","timestamp":1769926046039,"version":"3.49.0"},"reference-count":33,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2022,8,27]],"date-time":"2022-08-27T00:00:00Z","timestamp":1661558400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Introduction: Understanding hypoxemia, with and without the clinical signs of acute respiratory failure (ARF) in COVID-19, is key for management. Hence, from a population of critical patients admitted to the emergency department (ED), we aimed to study silent hypoxemia (Phenotype I) in comparison to symptomatic hypoxemia with clinical signs of ARF (Phenotype II). Methods: This multicenter study was conducted between 1 March and 30 April 2020. Adult patients who were presented to the EDs of nine Great-Eastern French hospitals for confirmed severe or critical COVID-19, who were then directly admitted to the intensive care unit (ICU), were retrospectively included. Results: A total of 423 critical COVID-19 patients were included, out of whom 56.1% presented symptomatic hypoxemia with clinical signs of ARF, whereas 43.9% presented silent hypoxemia. Patients with clinical phenotype II were primarily intubated, initially, in the ED (46%, p &lt; 0.001), whereas those with silent hypoxemia (56.5%, p &lt; 0.001) were primarily intubated in the ICU. Initial univariate analysis revealed higher ICU mortality (29.2% versus 18.8%, p &lt; 0.014) and in-hospital mortality (32.5% versus 18.8%, p &lt; 0.002) in phenotype II. However, multivariate analysis showed no significant differences between the two phenotypes regarding mortality and hospital or ICU length of stay. Conclusions: Silent hypoxemia is explained by various mechanisms, most physiological and unspecific to COVID-19. Survival was found to be comparable in both phenotypes, with decreased survival in favor of Phenotype II. However, the spectrum of silent to symptomatic hypoxemia appears to include a continuum of disease progression, which can brutally evolve into fatal ARF.<\/jats:p>","DOI":"10.3390\/jcm11175034","type":"journal-article","created":{"date-parts":[[2022,8,29]],"date-time":"2022-08-29T03:34:56Z","timestamp":1661744096000},"page":"5034","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Silent Hypoxemia in the Emergency Department: A Retrospective Cohort of Two Clinical Phenotypes in Critical COVID-19"],"prefix":"10.3390","volume":"11","author":[{"given":"Karine","family":"Alam\u00e9","sequence":"first","affiliation":[{"name":"Emergency Department, H\u00f4pitaux Universitaires de Strasbourg, 67000 Strasbourg, France"},{"name":"CREMS Network (Clinical Research in Emergency Medicine and Sepsis), 67201 Wolfisheim, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Elena Laura","family":"Lemaitre","sequence":"additional","affiliation":[{"name":"Emergency Department, H\u00f4pitaux Universitaires de Strasbourg, 67000 Strasbourg, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2527-8458","authenticated-orcid":false,"given":"Laure","family":"Abensur Vuillaume","sequence":"additional","affiliation":[{"name":"CREMS Network (Clinical Research in Emergency Medicine and Sepsis), 67201 Wolfisheim, France"},{"name":"Emergency Department, Regional Hospital of Metz-Thionville, 57700 Hayange, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Marc","family":"Noizet","sequence":"additional","affiliation":[{"name":"Emergency Department, Mulhouse Hospital, 68100 Mulhouse, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yannick","family":"Gottwalles","sequence":"additional","affiliation":[{"name":"Emergency Department, Colmar Hospital, 68000 Colmar, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tahar","family":"Chouihed","sequence":"additional","affiliation":[{"name":"Emergency Department, Nancy University Hospital, 54000 Nancy, France"},{"name":"Centre d\u2019Investigations Cliniques-1433, and INSERM U1116, F-CRIN INI-CRCT, Universit\u00e9 de Lorraine, 54000 Nancy, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Charles-Eric","family":"Lavoignet","sequence":"additional","affiliation":[{"name":"CREMS Network (Clinical Research in Emergency Medicine and Sepsis), 67201 Wolfisheim, France"},{"name":"Emergency Department, Nord Franche Comt\u00e9 Hospital, 90400 Tr\u00e9venans, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lise","family":"B\u00e9rard","sequence":"additional","affiliation":[{"name":"CREMS Network (Clinical Research in Emergency Medicine and Sepsis), 67201 Wolfisheim, France"},{"name":"Emergency Department, Haguenau Hospital, 67504 Haguenau, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lise","family":"Molter","sequence":"additional","affiliation":[{"name":"Emergency Department, Verdun Hospital, 55100 Verdun, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8490-4706","authenticated-orcid":false,"given":"St\u00e9phane","family":"Gennai","sequence":"additional","affiliation":[{"name":"Emergency Department, Reims University Hospital, 51100 Reims, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sarah","family":"Ug\u00e9","sequence":"additional","affiliation":[{"name":"Emergency Department, H\u00f4pitaux Universitaires de Strasbourg, 67000 Strasbourg, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Fran\u00e7ois","family":"Lefebvre","sequence":"additional","affiliation":[{"name":"Department of Public Health, University Hospital of Strasbourg, 75016 Paris, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0904-4600","authenticated-orcid":false,"given":"Pascal","family":"Bilbault","sequence":"additional","affiliation":[{"name":"Emergency Department, H\u00f4pitaux Universitaires de Strasbourg, 67000 Strasbourg, France"},{"name":"CREMS Network (Clinical Research in Emergency Medicine and Sepsis), 67201 Wolfisheim, France"},{"name":"INSERM (French National Institute of Health and Medical Research), UMR 1260, Regenerative NanoMedicine (RNM), F\u00e9d\u00e9ration de M\u00e9decine Translationnelle (FMTS), University of Strasbourg, 75016 Paris, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9141-6439","authenticated-orcid":false,"given":"Pierrick","family":"Le Borgne","sequence":"additional","affiliation":[{"name":"Emergency Department, H\u00f4pitaux Universitaires de Strasbourg, 67000 Strasbourg, France"},{"name":"CREMS Network (Clinical Research in Emergency Medicine and Sepsis), 67201 Wolfisheim, France"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,8,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1239","DOI":"10.1001\/jama.2020.2648","article-title":"Characteristics of and Important Lessons from the Coronavirus Disease 2019 (COVID-19) Outbreak in China: Summary of a Report of 72314 Cases from the Chinese Center for Disease Control and Prevention","volume":"323","author":"Wu","year":"2020","journal-title":"JAMA"},{"key":"ref_2","unstructured":"(2022, August 16). 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