A prehospital stroke scale is a standardized assessment tool used by emergency medical personnel, such as paramedics and emergency medical technicians, to quickly identify the signs of a potential stroke. These tools are applied in the field, often at a patient’s home or at the scene of an incident, before the individual arrives at a hospital. The scales provide a structured way to observe specific neurological deficits that frequently occur during a stroke. This early evaluation helps emergency responders make informed decisions about immediate patient care and transport.
Common Stroke Assessment Tools
One of the most widely recognized prehospital stroke assessment tools is the Cincinnati Prehospital Stroke Scale (CPSS). This scale evaluates three distinct signs: facial droop, arm drift, and abnormal speech. To check for facial droop, a paramedic will ask the individual to smile or show their teeth, observing if one side of the face moves less or appears uneven. For arm drift, the person is asked to close their eyes and hold both arms straight out in front of them for about 10 seconds; if one arm drifts downward, it suggests weakness. Speech abnormalities are assessed by asking the person to repeat a simple, familiar phrase, such as “You can’t teach an old dog new tricks,” and listening for slurring, incorrect words, or an inability to speak at all.
Building upon the CPSS, the FAST acronym (Face, Arms, Speech, Time) offers a simplified public awareness message. The “F,” “A,” and “S” correspond to facial droop, arm weakness, and speech difficulty. The “T” for “Time to call emergency services” emphasizes the urgency for both the public and responders to act swiftly if symptoms are observed.
The BE-FAST scale incorporates two additional components to enhance detection, particularly for strokes affecting the posterior brain. “B” stands for Balance (sudden loss of balance or coordination). “E” represents Eyes (sudden blurred, double, or lost vision). These additions identify a broader range of stroke presentations.
The Purpose of Rapid Field Assessment
Rapid prehospital stroke assessment is based on the principle that “time is brain.” During an untreated ischemic stroke, approximately 1.9 million brain cells can die every minute. This underscores the urgency of identifying symptoms quickly, as every minute saved in diagnosis and treatment can significantly impact a patient’s outcome and reduce long-term disability.
Early identification in the field directly influences a patient’s eligibility for time-sensitive treatments. Thrombolytic therapy, involving clot-busting drugs like tissue plasminogen activator (tPA), can dissolve blood clots and restore blood flow to the brain. This treatment is most effective when administered within a narrow window, typically within 4.5 hours of symptom onset. Beyond this timeframe, the benefits diminish, and the risks increase.
Another time-dependent intervention is mechanical thrombectomy, a procedure to physically remove large blood clots from brain arteries. This treatment can be performed up to 24 hours after symptom onset in selected patients, though earlier intervention generally yields better results. Paramedics assessing a patient in the field play a significant role in initiating the chain of care for these interventions. Swift recognition of stroke signs allows for immediate activation of hospital resources, setting the stage for prompt treatment.
From Field Assessment to Hospital Care
When a prehospital stroke scale indicates a potential stroke, paramedics will initiate a “stroke alert” or “stroke code” with the receiving hospital. This pre-arrival notification is a standardized communication that signals the impending arrival of a patient with suspected stroke symptoms. The information relayed includes the patient’s symptoms, the time of symptom onset (or last known well time), and the results of the field assessment.
This early warning allows the hospital’s specialized stroke team to mobilize and prepare for the patient’s arrival. This team typically includes neurologists, emergency department staff, radiologists, and nurses who specialize in stroke care. By having the team ready, the hospital can bypass traditional emergency department triage, taking the patient directly for immediate diagnostic imaging, such as a CT scan of the brain. This streamlined process aims to minimize delays, ensuring that time-sensitive treatments can begin as quickly as possible upon the patient’s arrival.
The field assessment also helps determine the most appropriate destination hospital. Patients presenting with signs of a large vessel occlusion (LVO) stroke, which involves a blockage in one of the brain’s major arteries, may be directly transported to a Comprehensive Stroke Center. These specialized centers offer advanced capabilities, including 24/7 access to neurosurgical interventions and endovascular procedures like thrombectomy, which are not typically available at all hospitals. Directing patients to the facility best equipped to manage their specific type of stroke optimizes their chances for recovery.