Mild Hypothermia After Endovascular Treatment in Acute Ischemic Stroke

Inclusion Criteria: 1. Subjects who submitted a written informed consent prior to the participation in the current clinical trial (If the subjects have conditions that they cannot decide on study participation according to their own will, they would participate in the study after their legal representatives submitted a written informed consent form. During the period of study participation, if patients' medical conditions are improved, the written informed consent should be submitted again.) 2. Patients with ischemic stroke attributed to carotid artery or middle cerebral artery occlusion achieved successful recanalization (TICI 2b or 3) immediately after endovascular treatment within 8 hours of symptom onset: Onset time was defined as the time when patients were lastly seen normal. 3. Patients of both sexes aged between 18 and 80 years old 4. NIHSS scores of 6-25 points at screening 5. mRS 1 prior to the onset of disease, with proximal cerebral artery occlusion (e.g., those with middle cerebral or internal carotid artery) Exclusion Criteria: 1. No evaluation for cranial artery before endovascular treatment 2. Patient with emergent stenting insertion in intracranial or extracranial artery 3. Transient ischemic attack or lacunar infarction 4. Platelet counts \< 75,000/mm3 5. coagulopathy (INR spontaneously \>1.5) 6. Hemodynamic instability 7. acute myocardial infarction, acute unstable angina or severe cardiac failure (NYHA classification ≥III) 8. Sepsis 9. Pregnant or breastfeeding women 10. Premorbid modified Rankin Scale Scores of \> 2 points 11. Hypersensitivity or allergy to following: buspirone, dexmedetomidine, meperidine 12. Intracranial hemorrhage or hemorrhagic transformation in initial CT scan 13. Brain tumor or CNS infection 14. Patients who participated in other clinical trials within 3 months 15. Life expectancy within 1 year