BE-FAST

Prehospital Stroke Recognition

B
Balance
"Did you suddenly lose your balance or have trouble walking?"
Sudden onset unsteadiness or falls
Ataxic gait — can they walk to the ambulance?
Truncal instability when sitting
Compare to their normal baseline
E
Eyes
"Are you seeing double, or has your vision changed suddenly?"
New diplopia — cover each eye, check if it resolves
Visual field loss — "Can you see my hand on each side?"
Gaze deviation or abnormal nystagmus
Sudden painless visual loss
F
Face
"Can you give me a big smile and show me your teeth?"
Unilateral facial droop or asymmetry
Facial numbness or tingling (ask them)
Crooked smile — compare both sides
A
Arms
"Hold both arms out straight in front with eyes closed for 10 seconds."
Pronator drift — one arm rotates or drops
Unilateral weakness or inability to raise
Limb numbness or heaviness reported
S
Speech
"Can you say: 'The traffic lights changed to green'?"
Slurred or dysarthric speech
Word-finding difficulty or wrong words
Unable to understand you (receptive dysphasia)
Scanning speech — slow, monotone, irregular rhythm
T
Time
Last known well time — ask patient, family, bystanders
Establish exact time of symptom onset
If woke with symptoms — last seen normal = time of sleep
Note time on scene, time of pre-alert
Thrombolysis window: 4.5 hrs · Thrombectomy: up to 24 hrs
⚠ Posterior Circulation — FAST Can Miss This
Posterior fossa strokes (cerebellum, brainstem) often present with vertigo, vomiting, and ataxia alone — no facial droop, no arm weakness, no speech change. BE-FAST will be negative. Acute onset + no prior history + new or assumed new HTN = stroke pathway regardless of FAST result. Consider Wallenberg syndrome if vertigo is prominent.
AVVV — Posterior Stroke Reminder (WMAS)
A mnemonic, not a screening tool — used to prompt consideration of posterior circulation stroke when BE-FAST is negative. Any feature present = convey with stroke concern documented.
A
Ataxia
Sudden loss of balance, coordination, or difficulty walking — compare to baseline
V
Vertigo
Severe acute dizziness or sensation of the room spinning — sudden onset
V
Vomiting
Sudden unexplained nausea or vomiting — especially with no GI history
V
Visual deficit
Sudden loss of vision, double vision, or visual field disturbance
Conveyance rationale: Acute onset · No prior history · Assumed new HTN · Previously fit and well · No alternative diagnosis that fits. A FAST-negative result does not require an alternative explanation — "acute, new, and unexplained" is sufficient grounds to convey and document posterior stroke concern. Document AVVV positives explicitly on the PRF.
Any positive = Pre-Alert as Stroke

State: suspected stroke, time of onset, BE-FAST positives, GCS, AVVV features if FAST negative
Do not delay on scene. Nearest HASU if FAST positive. ED with documented posterior concern if FAST negative.