First, the patient or a witness must recognize that a probable stroke is occurring. Inability to recognize the symptoms of acute stroke or denial of the symptoms and delayed calling for help is a common reason for delayed presentation and consequent ineligibility for treatment with tPA. Various community education strategies have shown small improvements in the ability of lay people to recognize a potential acute stroke. The American Stroke Association (part of the American Heart Association) along with individual medical centers have been sponsoring advertisements for the lay public in various mass media about the signs of acute stroke, and the need to activate EMS without delay. Better general awareness is likely to increase the proportion of stroke patients presenting early after symptom onset. Earlier presentation of acute stroke victims to a stroke center should increase the proportion of eligible and thrombolysed patients.

Ideally, the EMS should be contacted first as soon as an acute stroke is suspected. It is vital for EMS personnel to be familiar with acute stroke symptoms. Suspicion of acute stroke should be followed by urgent dispatch of an ambulance equipped at least for basic life support. Once on the scene, EMS personnel follow a set of guidelines that include hemodynamic and respiratory assessments. If the hemodynamic and respiratory parameters are stable and the history is consistent with stroke, a focused neurological assessment should be done to further evaluate for stroke. The Cincinnati Pre-hospital Stroke Scale [10] considers facial droop, arm drift, and speech disturbance and is useful in distinguishing stroke from other disorders on the scene. The Los Angeles Prehospital Stroke Scale (LAPSS) uses a composite of historical elements (age, history of seizure disorder, symptom duration, and pre-stroke ambulatory status), glucose level and a focused exam looking for obvious asymmetry (face, arm and grip) [11]. Further, a motor score that uses the exam elements of the LAPSS, may be useful tool to quantify stroke severity and likelihood of a large vessel occlusion in the prehospital setting [12, 13]. Once acute stroke is determined to be the likely diagnosis, transport to the nearest stroke center should proceed without delay.

While in transit to the Emergency Department (ED), other important steps by EMS include establishing an intravenous catheter access, measuring a blood glucose level, notifying the destination ED that a likely acute stroke victim is on the way, collecting a blood sample for immediate analysis upon ED arrival, and an initial attempt at establishing an accurate time of stroke onset. Notification of the ED that a likely acute stroke victim is on the way should be followed by activation of the Stroke Team and the neuroimaging staff to expedite assessment once the victim arrives at the ED. Some code stroke teams have increased their efficiency of t-PA treatment by alerting all the stroke team members simultaneously that a potential victim is on the way to their ED.

Neurological stroke deficits—such as neglect or aphasia—usually require contacting a witness to help estimate the time of stroke onset. Whenever possible a witness should accompany the stroke victim to the ED or be available for questioning by telephone. Intravenous infusion in the field may include isotonic solutions, such as Normal Saline, but should not include hypotonic solutions, such as 5 % dextrose, as they may predispose to cerebral edema. Sedating medications should be avoided as they interfere with neurological assessment.

A Stroke Team functions best if activated before the patient arrives in the ED, allowing an opportunity for team members to be present when the patient arrives. On arrival at the ED, potential stroke victims should be reassessed without delay. Several actions need to be completed to establish a reasonably accurate diagnosis and to decide if thrombolysis is indicated. Because earlier treatment with t-PA is more effective than later treatment (time is brain), it is best to perform the needed actions simultaneously to the extent possible [14].

Aphasia is usually recognized during an unsuccessful attempt at obtaining the history of present illness from the patient. There may be decreased comprehension, decreased ability to express oneself fluently, or both. Patients with aphasia usually cannot respond correctly when asked about the current date or place, and they sometimes realize their communication deficit and are frustrated by it. Aphasia implies left fronto-temporal brain dysfunction and is typically associated with right hemiparesis. Dysarthria is assessed independently from aphasia.

Ideally the history and physical examination are completed soon after the neuroimaging is completed and the necessary laboratory test results become available. At that time, the decision can be made whether the patient qualifies for intravenous t-PA therapy. An acute stroke t-PA assessment sheet (Table 10.3) may be used during code stroke to provide a readily visible, informative, and evolving record of the data needed for a treatment decision. The various data items in this sheet could be added by different members of the stroke team as they become available, to clearly and promptly indicate the t-PA treatment inclusion and exclusion criteria, and the time intervals between the various assessment steps.