Inclusion Criteria- Male and female patients 18 - 80 years;
- Clinical suspicion of an AIS (measurable or fluctuating neurological deficit with a National Institutes of Health Stroke Scale [NIHSS] ≥ 4 points) within 24 hours from symptom-onset;
- Extracranial (internal carotid artery) or intracranial (internal carotid artery; middle/anterior/posterior cerebral arteries) ≥ 50% stenosis, near-occlusion or occlusion diagnosed by ultrasound, computed tomography angiography (CTA) or magnetic resonance angiography (MRA), corresponding to acute neurological deficit;
- High-risk of having sleep apnea (classified by the Berlin sleep apnea questionnaire); or history of known sleep apnea; or witnessed repetitive apnea episodes during sleep or somnolence during hospitalization;
- Written informed consent by participants; alternatively by proxy or two physicians when not obtainable by patient or proxy (according to local regulations).
Exclusion Criteria- Perceived course towards the malignant middle cerebral artery infarction;
- Immediate or perceived need for intubation;
- Known sleep apnea currently on non-invasive ventilatory treatment;
- Standard contraindications for non-invasive ventilatory treatment;
- Pre-morbid modified Rankin scale (mRS) score ≥ 3;
- Severe comorbidities (i.e., severe heart failure, severe obstructive lung disease, active malignant disease, severe dementia);
- Pregnant and breast feeding women;
- Participation in another clinical trial other than standard-of-care registry.