Stroke scales: 10 things you need to know to save lives

EMS use of scales to determine stroke severity can have a significant impact on patient outcomes; here’s how.

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 [1].

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.

3. NIH Stroke Scale

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.

4. Cincinnati Prehospital Stroke Scale

The Cincinnati Prehospital Stroke Scale (CPSS) takes the least amount of time to perform and is one of the most widely used in EMS. The CPSS or, as it is sometimes referred to, Cincinnati scale assesses for:

• Facial droop
  • Ask the patient to smile and show their teeth. A droop to one side is a positive finding.
• Arm drift
  • 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.
• Slurred speech
  • 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.[2]

5. Los Angeles Motor Score

The Los Angeles Motor Score (LAMS) is another popular scale that can be performed quickly. The facial droop and arm drifts are tested the same way as in the CPSS, though grip strength is assessed instead of speech. Points are assigned to the findings to determine stroke severity. LAMS includes screening for:

• Facial droop with smile
  • Absent = 0
  • Present = 1
• Arm Drift
  • Absent = 0
  • Drifts down on one side = 1
  • Falls rapidly on one side = 2
• Grip Strength
  • Normal = 0
  • Weak grip on one side = 1
  • No grip on one side = 2

A score of one or two is positive for a stroke, four or higher is a high probability of ELVO.

6. Rapid Arterial oCclusion Evaluation Scale

Rapid Arterial oCclusion Evaluation (RACE) is the most recent scale developed and is gaining popularity. RACE takes slightly more time to perform than the CPSS and LAMS, with the goal of more accurately identifying stroke severity and localizing the area affected by the stroke. RACE includes:

• Facial palsy - weakness on one side of face with smile.
  • Absent = 0
  • Mild (some facial movement) = 1
  • Moderate to severe (little to no facial movement) = 2
• Arm motor function - the same test as Cincinnati and Los Angeles scales.
  • Normal to mild = 0
  • Moderate (able to lift arm, but unable to hold it for 10 seconds) = 1
  • Severe (unable to raise arm) = 2
• Leg motor function - ask the patient to lift each leg.
  • Normal to mild (able to lift leg and hold for five seconds) = 0
  • Moderate (able to lift, but unable to hold for five seconds) = 1
  • Severe (unable to lift one leg off of bed at all) = 2
• Head and gaze deviation - if the patient’s head or eyes are towards one side, ask them to look towards the other side.
  • Absent = 0
  • Present (unable shift gaze past midline) = 1
• 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.
  • Performs both tasks correctly = 0
  • Performs 1 task correctly = 1
  • Performs neither task = 2
• 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.
  • Patient recognizes his/her arm = 0
  • Does not recognize his/her arm or the impairment = 1
  • Does not recognize his/her arm nor the impairment = 2

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.[3] The RACE scale had positive results when tested among paramedics in Spain,[4] 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. Interdisciplinary teams can also quickly assess patients’ needs ahead of arriving at the hospital in mobile stroke units. A recent study revealed stroke patients transported via a mobile stroke unit receive a clot-busting procedure 10 minutes faster than when they are transported via an ambulance.

Read next: The evolution of a regional system of care in large vessel occlusion stroke

References:

1. 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.
2. Katz BS, McMullan JT, Scharew H, Adeoye O, Broderick JP. Design and validation of a prehospital scale to predict stroke severity: Cincinnati Prehospital Stroke Severity Scale (abstract). Stroke, published online before print April 21 2015
3. 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.
4. Perez de la Ossa N, Carrera D, Gorchs M, Querol M, Millan M, Gomis M, et al. Design and validation of a prehospital stroke scale to predict large arterial occlusion: The rapid arterial occlusion evaluation scale. Stroke, 2014; 45:87–91

This article was originally posted July 23, 2015. It has been updated.