1. Stroke scales activate a system of care.
Stroke is a major cause of death and disability, and patient outcomes depend on how quickly the blood flow can be restored to the damaged area of the brain. Stroke scales are standardized assessment tools used to identify stroke and clear a path to reperfusion. Treatment options for stroke include thrombolytic medications that aim to dissolve the clot, and interventional endovascular procedures (similar to a cardiac catheterization) to remove it. Successful stroke care requires early recognition, transporting the patient to a designated stroke center, and early activation of a stroke team at the hospital.
2. ELVO is the new STEMI.
The Emergent Large Vessel Occlusion (ELVO) was recently introduced as a type of stroke where a major cerebral artery is blocked, much like how a major coronary artery is blocked with STEMI. ELVO strokes have the highest rate of mortality and poor outcomes. Thrombolytics alone usually do not work for large vessel occlusions, and recent studies have shown that combined thrombolytics and endovascular procedure are the most effective treatment.
There are two tiers of stroke centers that offer different treatment options. Primary stroke centers are equipped to administer thrombolytics, and comprehensive stroke centers offer endovascular procedures. Stroke scales are now being used to both identify strokes and assess their severity, and to direct patients with suspected ELVOs to comprehensive centers. Several scales have been developed that attempt to do this, including the NIH Stroke Scale, Cincinnati Prehospital Stroke Scale, Los Angeles Motor Score, and Rapid Arterial Occlusion Evaluation.
The NIH stroke scale is a universal exam used in hospitals to determine stroke severity. It has 15 items to test, including level of consciousness, speech, vision, movement, and sensation. The exam takes approximately 10 minutes to complete, and is considered to be too time-consuming and cumbersome for prehospital use by EMS. The NIH scale is, however, the standard that stroke scales developed for EMS are compared to for sensitivity and specificity.
Ask the patient to smile and show their teeth. A droop to one side is a positive finding.
Ask the patient to hold their hands in front of them, palms up, as if they are holding a pizza box or tray. If one arm (not both) drifts to the middle, or they are unable to move one arm, that is a positive finding.
Ask the patient to repeat a short phrase, such as “you can’t teach an old dog new tricks” or "It’s a beautiful day in Cincinnati.” Slurring words or an inability to speak is a positive finding.
Any ONE of these CPSS findings suggests a stroke. A major limitation is that CPSS only assesses for the presence or absence of stroke - not severity, though a revised version is being tested.
A score of one or two is positive for a stroke, four or higher is a high probability of ELVO.
Facial palsy - weakness on one side of face with smile.
Arm motor function - the same test as Cincinnati and Los Angeles scales.
Leg motor function - ask the patient to lift each leg.
Head and gaze deviation - if the patient’s head or eyes are towards one side, ask them to look towards the other side.
If a right-side deficit is found, check for aphasia (inability to say or hear words correctly). Ask the patient to close their eyes and make a fist.
If a left-side deficit is found, check for agnosia (an inability to process sensory information). Touch their arm and ask “whose arm is this?” Then ask them to raise both hands and clap.
A stroke is likely with a score above 1, and ELVO is likely if the cumulative score is above 5.
7. Stroke scales are a work in progress.
Patients with ELVOs are best served at comprehensive stroke centers. However, most strokes do not involve major arteries and can be managed at primary stroke centers. Using stroke scales to determine stroke severity guides patients to the closest appropriate hospital and best utilizes resources.
EMS determination of stroke severity is a new concept, and the best scale to do this has yet to be determined. The Cincinnati and Los Angeles scales have been validated in hospital trials, but studies are mixed when applied by EMS. The RACE scale had positive results when tested among paramedics in Spain, is being adopted by many EMS systems in the United States, and more studies of it are underway.
It is important to monitor the outcomes of patients who receive a stroke screen to assess the accuracy of the test and protocol compliance by EMS providers. It is also important to be nimble and adapt as more research on stroke scales is published.
8. Use job aids to improve accuracy.
EMS providers must be able to quickly perform their service’s stroke screen. However, it is unrealistic to expect that each step and point assignment be committed to memory and recalled under stress. Use a checklist or smartphone app as a reference to ensure that steps are not missed. The job aid should also include common stroke mimics to check for, such as Bell’s Palsy, seizure, and hypoglycemia, to prevent false stroke team activations.
9. Report the score and stroke exam findings.
Clear communication between EMS and stroke center personnel is vital for minimizing delays in care. This is a potential failure point, especially when multiple EMS services that transport to a single hospital use different stroke scales. Reporting “a RACE score of 5 for moderate facial palsy, moderate arm drift, moderate leg weakness, and inability to make fist” takes a bit more time, but provides better information for the hospital’s stroke team to prepare for the patient’s arrival.
10. Telemedicine may improve decision making and speed up care.
Some services have incorporated apps into their stroke assessment that instantly transmit stroke scale findings to the hospital. Smartphone apps, such as FaceTime, also allow physicians at the stroke center to see the patient and discuss a treatment plan with EMS before transport is initiated, reduce the time to treatment at the appropriate destination, and share data for quality improvement.
Smith EE, Schwamm LH. Endovascular clot retrieval therapy: implications for the organization of stroke systems of care in North America. Stroke, published online before print May 5 2015.
Asimos AW, Ward S, Brice JH, Rosamond WD, Godstein LB, Studnek J. Out-of-hospital stroke screen accuracy in a state with an emergency medical services protocol for routing patients to acute stroke centers. Annals of Emergency Medicine, 2014; 64 (5) 509-515.