BE FAST Stroke Signs: BEFAST, the Cincinnati Stroke Scale, LAMS and Last Known Well

BE-FAST is a quick way to recognize the signs of a stroke: Balance, Eyes, Face, Arms, Speech and Time. It is an extension of FAST, the public-education message built around the face, the arms and speech, and it adds the two signs FAST most often misses. For an EMS provider it sits beside the Cincinnati Prehospital Stroke Scale, a screen for whether this is a stroke, and a large-vessel-occlusion scale such as LAMS, which asks how severe the deficit is. None of them is a diagnosis, and none of them replaces a blood glucose or a clear last known well time.

BE-FAST: the signs of a stroke

How BE-FAST extends FAST

FAST was designed to teach the public the commonest signs of a stroke. Its three physical signs are all about the face, the arms and speech, which fits strokes in the front of the brain (the anterior circulation) well. Strokes in the back of the brain (the posterior circulation, which supplies the brainstem, the cerebellum and the vision centers) can present instead with dizziness, unsteadiness, vomiting and loss of vision, and can pass all three FAST signs. A study by Aroor and colleagues in 2017 found that adding balance and eyes picked up strokes that FAST alone missed, and BE-FAST is now used in public education and by many EMS systems.

Other stroke signs are worth knowing even though no acronym holds them: a sudden, severe headache unlike any before (more typical of a bleed), sudden confusion, sudden numbness on one side of the body, and a sudden inability to walk. Any sudden neurological change is a stroke until something else explains it.

The Cincinnati Prehospital Stroke Scale

The Cincinnati Prehospital Stroke Scale was developed by Kothari and colleagues as a short version of the much longer NIH Stroke Scale, and validated for EMS use in their 1999 paper. It tests three things, and it asks one question: is this likely to be a stroke?

Any one abnormal finding is a positive screen. The number of abnormal findings is not a severity: one abnormal finding and three are the same answer to the question this scale asks. A negative screen does not rule out a stroke. The scale was built around strokes in the front of the brain, and a posterior stroke can pass all three items, which is exactly the gap the B and E in BE-FAST are meant to close.

Score the Cincinnati screen and LAMS side by side, with time since last known well

Large-vessel-occlusion scales such as LAMS

A large-vessel occlusion is a clot blocking one of the major arteries of the brain. These strokes cause the largest deficits, and some can be treated by removing the clot at a center equipped to do it. A large-vessel-occlusion scale asks a different question from the Cincinnati screen: not whether this is a stroke, but how severe the deficit is.

The Los Angeles Motor Scale (LAMS), published by Llanes and colleagues in 2004, scores three motor findings. A total of 4 or more is the threshold, from a study by Nazliel and colleagues, at which the scale is taken to suggest a large-vessel occlusion. Other scales in US use include RACE, VAN and FAST-ED, and your protocol names the one your service uses.

• The total runs from 0 to 5, and three zeros is a real total of 0.
• A LAMS total speaks to the severity of a motor deficit and says nothing about whether a stroke is present. A low LAMS does not mean no stroke.
• The Cincinnati screen and LAMS answer different questions and are never added together into one number.
• A LAMS at or above the threshold suggests severity. It is not a destination decision, which belongs to your regional stroke plan.

Last known well, not time of onset

Last known well is the last time somebody saw the patient at their normal baseline. It is the time the hospital asks for first, because the treatments that can open a blocked artery or remove a clot are limited by time, and the clock is measured from last known well. Which treatments are still possible at a given time is the receiving center's decision, and it differs by treatment and by hospital.

• If somebody saw the symptoms start, the time they started is the last known well time.
• If nobody saw them start, the last known well time is when the patient was last seen normal, not when they were found. A patient found at 0800 who was last seen normal at 2200 the night before has a last known well of 2200.
• A patient who wakes up with symptoms was last known well when they were last seen normal before going to sleep, unless somebody saw them normal later in the night.
• If the symptoms went away completely and then came back, many protocols take the time the patient was last back to normal as the new last known well. Confirm the rule your protocol uses.
• Ask the person who saw the patient last, write down the exact time, and bring the witness or get a phone number. The hospital may need to ask them more.

Documenting the time of discovery as the time of onset is a common error. It makes the stroke look newer than it is, and that can lead the hospital to a decision built on the wrong clock.

Stroke mimics

Several conditions look like a stroke and score positive on stroke scales. The first one to check for is the one you can fix on scene.

Mimics are a reason to look carefully, not a reason to downgrade the call. When you cannot tell, treat the patient as a stroke. A stroke and a mimic can also exist together, and a bleed in the brain cannot be told apart from a clot in the field: imaging decides.

Field priorities

The principles below are common to EMS curricula. How each one is carried out, which scale you use, and where the patient goes are your protocol's.

• Airway, breathing and circulation first. A patient with a large stroke may not be able to protect their airway.
• Check a blood glucose before anything else that depends on the stroke scale.
• Do a stroke screen, and a large-vessel-occlusion scale if your protocol uses one.
• Establish the last known well time and write it down.
• Notify the receiving facility early with the last known well time, the scale results and the glucose, so the stroke team is ready when you arrive.
• Give oxygen only if the saturation is low, as your protocol directs.
• Nothing by mouth until swallowing has been assessed. Many stroke patients cannot swallow safely.
• Leave a raised blood pressure alone unless your protocol directs otherwise, and report it. Lowering it before imaging can reduce flow to the brain tissue that is still salvageable.
• Put the patient on the monitor, and establish vascular access en route if your protocol calls for it without delaying transport.
• Get the medication list, especially any blood thinner and when it was last taken.
• Transport without delay, to the destination your regional stroke plan names, and reassess the neurological exam on the way.

Score a Glasgow Coma Scale to track the level of consciousness

The short version

• BE-FAST: Balance, Eyes, Face, Arms, Speech, Time. Balance and eyes catch strokes in the back of the brain that FAST can miss.
• The Cincinnati Prehospital Stroke Scale asks whether this is a stroke. Any one abnormal item is positive, and a negative screen does not rule a stroke out.
• LAMS and other large-vessel-occlusion scales ask how severe the deficit is. A LAMS of 4 or more suggests an occlusion; a low LAMS does not mean no stroke.
• Check the glucose first. Hypoglycemia is the mimic you can fix.
• Last known well is when the patient was last seen normal, not when they were found.
• Notify early, leave the blood pressure alone unless protocol says otherwise, and let your regional stroke plan decide the destination.