A 72-year-old woman with a history of type 2 diabetes and hypertension presents with sudden onset slurred speech and right-sided facial droop noted 1 hour ago. Her BP is 160/90 mmHg, HR 88 bpm, RR 16/min, SpO2 97% on air, and blood glucose is 8.2 mmol/L. A non-contrast CT head is performed immediately and shows no evidence of intracranial haemorrhage or established infarction. What is the single most appropriate next step in management?