The purpose of this RCT trial is to evaluate whether the sequential hyperbaric oxygen therapy can improve the 90-day functional outcome in patients with acute large vessel occlusion ischemic stroke after endovascular treatment.

This is a multicenter, prospective, open-label, endpoint-blinded, randomized controlled trial with a 1:1 ratio, comparing the effect of hyperbaric oxygen therapy plus standard medical treatment versus standard medical treatment alone after endovascular treatment in patients with acute large vessel occlusion ischemic stroke. The primary outcome is modified Rankin Scale (mRS) score distribution at 90 days (±14 days) after randomization.

Inclusion Criteria:

1. Age 18~80 years;
2. Clinically diagnosed as acute large vessel occlusive ischemic stroke, suitable for and received endovascular treatment according to current clinical guidelines;
3. The onset of stroke or the last normal time to the time of endovascular treatment ≤ 24 hours;
4. Pre-stroke mRS score of 0 or 1;
5. Baseline NIHSS score before endovascular treatment ≥ 6 points in the anterior circulation or ≥10 points in the posterior circulation;
6. CTA, MRA, or DSA angiography before endovascular treatment confirmed occlusion of large vessels (internal carotid artery, middle cerebral artery M1 segment, basilar artery), consistent with symptoms and signs;
7. The corresponding anterior circulation ASPECTS score or posterior circulation pc-ASPECTS score ≥ 6 points;
8. The pontine midbrain index (PMI) of patients with acute basilar artery occlusion ≤3;
9. Patients or their family members sign the informed consent form.

Exclusion Criteria:

1. Patients with extensive bleeding or severe increase in infarct area, midline displacement (>0.5cm), etc. during endovascular treatment, who plan to undergo bone valve decompression or ventricular drainage;
2. Known bleeding risk factors, including coagulation factor deficiency, or receiving anticoagulant therapy, INR>3.0 or APTT > 3 times normal or platelet count less than 50×10⁹/L;
3. Severe hepatic or renal dysfunction (severe hepatic dysfunction refers to ALT or AST > 3 times the upper limit of the normal range, severe renal dysfunction refers to serum creatinine Cr >1.5 times the upper limit of the normal range);
4. Females of pregnancy, or positive pregnancy test prior to randomization;
5. Severe persistent and medication-uncontrollable hypertension (systolic blood > 185 mmHg or diastolic blood > 110 mmHg)
6. Baseline blood glucose of <50 mg/dL (2.78 mmol/L) or >400 mg/dL (22.20 mmol/L);
7. The oxygen required to maintain 95% of peripheral arterial oxygen saturation (SaO2) under the current medium-term management guidelines > 3L/min;
8. End-stage disease other than the nervous system, life expectancy < 90 days;
9. Participating in other drug or medical device clinical trials;
10. CT or MR suggests intracranial tumors (other than meningiomas) or other high-risk intracranial vascular malformations;
11. Patients with anemia, polycythemia or other conditions requiring urgent oxygen;
12. Unable to cooperate with hyperbaric oxygen therapy, or have other diseases that are not suitable for hyperbaric oxygen therapy (such as active/chronic obstructive pulmonary disease, acute respiratory distress syndrome, tension pneumothorax, tension pneumocephalus, etc.).