Special Prehospital Procedures Distinctive prehospital methods deployed in FAST-MAG include : identifying likely stroke patients using the Los Angeles Prehospital Stroke Screen ; eliciting explicit informed consent from patients or on scene legally authorized representatives via cellphone discussion with off-scene physicians ; paramedic rating of pretreatment stroke severity using the Los Angeles Motor Scale ; assigning patients to a study arm using blinded , pre-encounter randomization ; facilitating continuity of study infusion from the field to the ED by stocking ambulances with study kits including both field and hospital doses ; and electronic fax consent signature documentation by geographically separated subjects and enrolling physicians .