Normobaric Hyperoxia Combined With Endovascular Treatment in Acute Ischemic Stroke (OPENS-2)

Inclusion criteria

General inclusion criteria

• It conforms to the indications for endovascular thrombectomy
• 18 ≦ Age ≦ 80 years old.
• The clinical symptoms and signs are consistent with acute anterior circulation large vessel occlusion; 10≤NIHSS≤20；
• (Level of consciousness) NIHSS score 0 or 1;
• The time from onset to randomization is within 6 hours of onset;
• The mRS score before stroke is 0-1;
• Patient and family members sign informed consent. Image inclusion criteria

• Preoperative CT or MR or DSA angiography found large vessel occlusion (internal carotid artery or middle cerebral artery M1 segment) that were consistent with symptoms and signs; 2. ASPECT score ≥ 6 points 3. <1/3 MCA area involvement (confirmed by CT or MRI)

Exclusion criteria

• General exclusion criteria

• Rapid neurological function improvement, NIHSS score less than 10 points, or evidence of vessel recanalization prior to randomization;
• Seizures at stroke onset;
• Intracranial hemorrhage;
• Symptoms suggestive of subarachnoid hemorrhage, even if CT scan was normal;
• Known hemorrhagic diathesis, coagulation factor deficiency, or on anticoagulant therapy with INR > 3.0 or PTT > 3 times normal;
• Platelet count of less than 100,000 per cubic millimeter;
• Severe hepatic or renal dysfunction;
• Severe, sustained hypertension (Systolic Blood Pressure >185 mmHg or Diastolic Blood Pressure >110 mmHg)
• Baseline blood glucose of <50mg/dL (2.78 mmol) or >400mg/dL (22.20 mmol)
• Active and chronic obstructive pulmonary disease or acute respiratory distress syndrome;
• >3 L/min oxygen required to maintain peripheral arterial oxygen saturation (SaO2) 95% as per current stroke management guidelines;
• Medically unstable;
• Life expectancy<90 days;
• Patients who could not complete the 90-day follow-up;
• Evidence of intracranial tumor;
• Patients with anemia or polycythemia vera or other situations that require urgent oxygen inhalation;
• Patients with upper gastrointestinal bleeding or nausea or vomiting so that they cannot cooperate with the mask to inhale oxygen.
• A history of severe allergies to contrast agents;
• There are any other conditions that are not suitable for endovascular treatment.

Image exclusion criteria

• CTA/MRAshows excessive bending of blood vessels, which may hinder the delivery of the device;
• Suspected cerebrovascular inflammation based on medical history and CTA/MRA;
• Suspected aortic dissection based on medical history and CTA/MRA
• CTA/MRA confirmed multi-vascular area occlusion (such as bilateral anterior circulation or anterior/posterior circulation), or bilateral infarction or multi- regional infarction;
• CTA/MRAconfirmed moyamoya disease or moyamoya syndrome;
• CT/MRI confirmed the obvious effect of midline shift
• CT/MRI confirmed the presence of intracranial tumors