RESEARCH Open Access Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome: insights from the LUNG SAFE study Fabiana Madotto 1,2 , Emanuele Rezoagli 3,4,5 , Tài Pham 6,7,8 , Marcello Schmidt 9 , Bairbre McNicholas 10 , Alessandro Protti 11,12 , Rakshit Panwar 13,14 , Giacomo Bellani 3,15 , Eddy Fan 4,8,9,16 , Frank van Haren 17 , Laurent Brochard 6,7,8 , John G. Laffey 4,5,6* , for the LUNG SAFE Investigators and the ESICM Trials Group Abstract Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO 2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO 2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO 2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO 2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO 2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO 2 . Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO 2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO 2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO 2 55–100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073 Keywords: Hyperoxia, Hypoxia, Hyperoxemia, Hypoxemia, Oxygen therapy, Acute respiratory distress syndrome, Mortality, Invasive mechanical ventilation © The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. * Correspondence: john.laffey@nuigalway.ie 4 Anaesthesia and Intensive Care Medicine, School of Medicine, National University of Ireland Galway, Galway, Ireland 5 Regenerative Medicine Institute (REMEDI) at CÚRAM Centre for Research in Medical Devices, Biomedical Sciences Building, National University of Ireland Galway, Galway, Ireland Full list of author information is available at the end of the article Madotto et al. Critical Care (2020) 24:125 https://doi.org/10.1186/s13054-020-2826-6