Fig. 3

Potential prehospital work flow with or without brain perfusion ultrasound (BPU), numbers are estimates based on all emergency stroke calls, including intracerebral hemorrhage (ICH), stroke mimics, stroke with large vessel occlusion (LVO). (1)—Primary transport of all suspected stroke patients admitted to the next regional stroke unit (rSU): short transport, widely available, fast symptom-to-needle time for thrombolysis, but no mechanical thrombectomy (MT) for LVO available. (2)—Secondary transport from the rSU to comprehensive stroke centers (CSC) for MT resulting in delay in symptom-to-groin time. (3)—Primary transport of all suspected stroke patients to CSCs: Longer symptom-to-needle times, short symptom-to-groin time, but congestion of CSC with non-LVO stroke patients. (4)—Prehospital identification of LVO using BPU and either direct transfer to CSC for MT or to rSU if no perfusion deficit detected