Oxygen is the most widely prescribed therapy in the ICU (intensive care unit) and can save lives in critical patients. While the deleterious effects of hypoxia are apparent and must be actively avoided, hyperoxia also has adverse effects. These include systemic, coronary and cerebral vasoconstriction; decreased coronary blood flow; pulmonary atelectasis and increased free radicals. Despite these deleterious effects, hyperoxia is common and frequent in the ICU (from 22% to 74%).

A recent meta-analysis published in "The Lancet" with more than 16,000 patients demonstrated an association between liberal oxygen therapy and mortality in critical patients. Other meta-analyses confirm its results with high quality data according to the authors.

A randomized controlled trial published in "The New England Journal of Medicine" comparing liberal versus conservative oxygen therapy showed no difference in mechanical ventilation days and mortality (The ICU-ROX, 2019). However, the difference in PaO2 between the two groups was very small and the PaO2 in the liberal group did not exceed 100 mmHg. In any case, conservative oxygen therapy is safe for critical patients.

The recommendations therefore recommend an oxygen saturation between 94-97% in critical patients and 88-92% in patients with COPD (Chronic Obstructive Pulmonary Disease) .

However, to our knowledge, no study has described the incidence of hyperoxia in non-intubated patients in the intensive care unit.

Inclusion Criteria:

• Patient having oxygen
• Not to be ventilated
• Being over 18 years old

Exclusion Criteria:

• Sickle cell disease patient
• Patient with pneumo/hemothorax
• Pregnant women, prisoners, denial of informed consent
• Patients who are related to an investigator
• Patients undergoing hyperbaric chamber therapy
• Patients with CO
• Patients on ECMO
• Patients with paracoate poisoning...
• Patients included in other interventional studies

Oxygen patients in intensive care hospitals and no-intubated