A 72-year-old female is BIBA to ED at 19:01 having a collapse at home. She was found by her husband lying on the floor, having trouble speaking properly and unable to move her right arm and leg. The husband called the ambulance at 17:40. It is unclear how long she has been lying on the floor. The patient has a PMHx of well-controlled type 2 diabetes, HTN and hypercholesterolaemia. She has had an appendectomy at the age of 9 and her brother had a haemorrhagic stroke at the age of 65. What is an important factor for thrombolysis?