Dangers of hyperoxia

• Published in: Critical care (London, England) Vol. 25; no. 1; pp. 440 - 15
• Main Authors: Singer, Mervyn, Young, Paul J, Laffey, John G, Asfar, Pierre, Taccone, Fabio Silvio, Skrifvars, Markus B, Meyhoff, Christian S, Radermacher, Peter
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 19-12-2021; BioMed Central; BMC
• Subjects: ARDS; Blood gases; Health aspects; Humans; Hyperoxaemia; Hyperoxia; Hyperoxia - complications; Ischemia; Lung; Lung diseases; Oxygen; Oxygen consumption; Reactive nitrogen species; Reactive Oxygen Species; Review; Risk factors; Sepsis; United Kingdom; Myocardial infarction; Reactive oxygen species; Traumatic brain injury; Acute ischaemic stroke; Reactive nitrogen species; Intracranial bleeding; Subarachnoidal bleeding; Cardiopulmonary resuscitation; Hyperoxia; Surgical site infection; Hyperoxaemia; Sepsis; ARDS; Trauma-and-haemorrhage
• ISSN: 1364-8535; 1466-609X; 1364-8535
• DOI: 10.1186/s13054-021-03815-y

Oxygen (O
) toxicity remains a concern, particularly to the lung. This is mainly related to excessive production of reactive oxygen species (ROS). Supplemental O
, i.e. inspiratory O
concentrations (F
O
) > 0.21 may cause hyperoxaemia (i.e. arterial (a) PO
 > 100 mmHg) and, subsequently, hyperoxia (increased tissue O
concentration), thereby enhancing ROS formation. Here, we review the pathophysiology of O
toxicity and the potential harms of supplemental O
in various ICU conditions. The current evidence base suggests that PaO
 > 300 mmHg (40 kPa) should be avoided, but it remains uncertain whether there is an "optimal level" which may vary for given clinical conditions. Since even moderately supra-physiological PaO
may be associated with deleterious side effects, it seems advisable at present to titrate O
to maintain PaO
within the normal range, avoiding both hypoxaemia and excess hyperoxaemia.