Can breathing pure oxygen boost stroke recovery?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Age≥18 years; 2. The time from onset to randomization is within 4.5 hours of onset; 3. The clinical diagnosis is acute ischemic stroke (the criteria followed the Chinese Guidelines for the Diagnosis and Treatment of Acute Ischemic Stroke 2018); 4. Baseline NIHSS (at the time of randomization) should be ≥5 and ≤25 points; 5. Pre-stroke mRS score≤1 points; 6. Informed consent from the patient or surrogate. Exclusion Criteria: 1. Intracranial hemorrhage (including parenchymal hemorrhage, intraventricular hemorrhage, subarachnoid hemorrhage, subdural/extradural hematoma, etc.); 2. Past history of intracranial hemorrhage; 3. Rapid neurological function improvement, NIHSS score less than 5 points; 4. Presence of proximal arterial occlusion on computed tomographic angiography(CTA)/magnetic resonance angiography(MRA) (e.g., intracranial internal carotid artery(ICA), middle cerebral artery(MCA)-M1, and vertebrobasilar arteries); 5. Massive anterior cerebral infarction identified by CT or MRI (ASPECT \< 6 or lesions larger than one third of the territory of the middle cerebral artery); 6. Intended to proceed endovascular treatment; 7. Pregnant women, or planning to become pregnant during the trial; 8. A history of severe head trauma or stroke within 3 months; 9. A history of intracranial or spinal surgery within 3 months; 10. A history of gastrointestinal or urinary bleeding within 3 weeks; 11. two weeks of major surgery; 12. Arterial puncture was performed at the hemostasis site that was not easily compressed within 1 week; 13. Active visceral bleeding; 14. Intracranial tumors, large intracranial aneurysms; 15. Aortic arch dissection was found; 16. Severe, sustained hypertension (Systolic Blood Pressure \>185 mmHg or Diastolic Blood Pressure \>110 mmHg); 17. Baseline blood glucose of \<50mg/dL (2.78 mmol) or \>400mg/dL (22.20 mmol); 18. Oral warfarin anticoagulant with international normalized ratio(INR)\>1.7 or prothrombin time(PT)\>15 s; 19. Heparin treatment was received within 24 h; 20. Thrombin inhibitors or factor Xa inhibitors were used within 48 h; 21. Propensity for acute bleeding, including platelet counts of less than 100×109/ L or otherwise; 22. Hereditary or acquired bleeding constitution; 23. Onset with seizures; 24. Severe liver and kidney dysfunction; 25. Active and chronic obstructive pulmonary disease or acute respiratory distress syndrome; 26. Patients with anemia or polycythemia vera or other situations that require urgent oxygen inhalation; 27. Patients with upper gastrointestinal bleeding or nausea or vomiting so that they cannot cooperate with the mask to inhale oxygen; 28. Life expectancy \< 1 year; 29. Patients who could not complete the 90-day follow-up; 30. Participation in other clinical trials within 3 months prior to screening; 31. Unsuitability or participation in this study as judged by the Investigator may result in subjects being exposed to greater risk.