Cincinnati Prehospital Stroke Scale (CPSS)

As clinicians, it is crucial that you be prepared to respond and assess many different types of emergencies quickly. Stroke is an emergency that is unfortunately common. Someone dies from a stroke every four minutes in the U.S. — which means you need to know how to spot and address the signs of stroke in high pressure situations.

The ACLS algorithm includes the assessment and treatment of stroke, with a focus on rapid recognition, stabilization, and transport to the appropriate facility for definitive care. Stroke assessment and study is perfectly complementary to ACLS training. By understanding and utilizing the Cincinnati Prehospital Stroke Scale (CPSS), ACLS-trained clinicians can help save lives and prevent long-term disability in stroke patients.

Why Is Stroke Assessment Important for ACLS Clinicians?

In an ACLS situation, we look for cardiovascular problems that present as cardiac issues. However vascular disease can present elsewhere in the body. In fact, 1 in 6 deaths from cardiovascular disease now occurs due to stroke. Because strokes are very common and also require a quick response time, ACLS team members should be trained and ready to assist stroke patients by knowing signs, symptoms, and assessment tools.

Let’s review the following impactful stroke statistics from the CDC:

• In the U.S., someone has a stroke every 40 seconds.
• Every year, almost 800,000 people in the U.S. suffer a stroke. Of those, nearly 1 in 4 of them have had a previous stroke.
• Most strokes (about 87%) are ischemic strokes resulting from some sort of vascular blockage (typically a plaque or clot).
• Stroke is one of the leading causes of disability and reduces mobility in greater than 50% of stroke survivors over age 65.

Many Americans are at an elevated stroke risk due to lifestyle factors and choices, such as smoking, lack of regular exercise, and an unhealthy diet. These habits lead to high blood pressure, high cholesterol, obesity, and type 2 diabetes, which are leading causes of stroke. One in three American adults has at least one of these health conditions.

The term “stroke” actually encompasses several types, categorized according to their causes:

• Ischemic stroke: Happens when a blood vessel in the brain is obstructed. This type is the most common, accounting for about 87% of all strokes.
• Hemorrhagic stroke: This kind of stroke occurs when a weak blood vessel ruptures, creating a brain bleed. Commonly precipitated by uncontrolled high blood pressure.
• Transient Ischemic Attack (TIA): This is often called a “mini stroke” and is caused by a temporary clot. These are considered warning signs of an ischemic stroke. Symptoms from TIAs usually resolve on their own.
• Cryptogenic stroke: This type of stroke happens due to an unknown cause, but some of the likely culprits are atrial fibrillation, a heart structure problem, atherosclerosis, or a blood clotting disorder.
• Brain Stem stroke: This type of stroke is very deadly and affects both sides of the body. The patient can become “locked in” or unable to speak or move below the neck.

“Time is Brain”

Time is of the essence when it comes to stroke response, just like with an acute cardiac or respiratory condition. One frequently taught phrase is that “time is brain,” emphasizing that human brain tissue dies rapidly as a stroke progresses. This concept has even been studied and quantified, concluding that the typical patient loses an astounding 1.9 million neurons each minute that a stroke is untreated.

When a patient becomes unresponsive or has a rapidly changing physical condition, one possibility that should be assessed and treated (or ruled out) immediately is an acute stroke. The signs and symptoms of a stroke can include any of the following:

• Weakness and numbness sensations, which can be on one or both sides of the body.
• Confusion and/or difficulty forming speech or comprehending spoken information.
• Severe headache. Patients often report “the worst headache of their lives.”
• Loss of coordination and poor balance.
• Loss of full or partial vision in one or both eyes.
• Difficulty walking or standing.

The faster emergency treatment begins, the greater chance the patient has of survival and surviving with brain function intact. Early recognition, fast response, and rapid treatment with fibrinolytic therapy (if indicated) is the key to successful outcomes.

To aid in the rapid assessment of stroke symptoms, the American Heart Association ACLS course recommends familiarity with the Cincinnati Prehospital Stroke Scale (CPSS). This scale is used in emergency situations and out-of-hospital environments as an important tool to determine neurological status and aid in stroke recognition.

What is the Cincinnati Prehospital Stroke Scale?

The CPSS originated at the University of Cincinnati (hence the name) in 1997. It is a shortened version derived from the National Institutes of Health Stroke Scale (NIHSS), which is a more involved assessment. The NIHSS is considered the gold standard for determining candidates for tissue plasminogen activator (tPA), a fibrinolytic therapy.

The CPSS is used by EMS to rapidly assess for the presence of three common abnormal findings:

1. Facial droop
2. Arm drift
3. Speech abnormalities

This information is used to rapidly diagnose a potential stroke and facilitate treatment and transport to the most appropriate setting (such as a certified stroke center).

CPSS Validity and Accuracy

The CPSS is preferred for its simplicity, ease of use, and rapid results. It takes less than one minute to conduct. However, it is also important that it be accurate and consistent for all clinicians. Many studies have been done to assess and compare the usefulness of this tool for evaluation of patients with stroke secondary to large vessel occlusion (LVO) — or an ischemic stroke.

The CPSS is not the only prehospital stroke scale. There are others, such as the Los Angeles Prehospital Stroke Screen (LAPSS), published in 2001, and the Rapid Arterial Occlusion Evaluation (RACE) scale from 2014. However, the CPSS is consistently recommended and cited and EMS statewide protocols as the recommended scale to use.

Soon after its development, the CPSS was studied to determine its validity and accuracy when performed by prehospital providers versus physicians. The findings affirmed its reliability at detecting stroke.

Results to note:

• For a total of 860 CPSS scales completed, the accuracy of results was determined to be at a 95% confidence interval (indicating high reproducibility).
• Correlation of results between physicians and prehospital providers was excellent at a range of 89 to 93%.
• The sensitivity in identifying patients who are candidates for thrombolytic therapy was 88%.
• Patients with new findings in one of the three assessment areas have a 72% likelihood of ischemic stroke. If all three categories have findings, the probability is greater than 85%.

Similar results have been found in subsequent studies, as well as in repeated use. All of these led to the CPSS being considered a reliable tool for rapid stroke diagnosis in contemporary medicine.

Clinicians should be careful not to confuse CPSS with another scale, the Cincinnati Prehospital Stroke Severity Scale (CPSSS).

How to Administer the CPSS Assessment

Although the CPSS is designed to be a simple assessment, it is useful to practice and observe carefully. Sometimes a sign may be subtle or may worsen over a few minutes. If ANY ONE of the three signs shows abnormal findings, this means that the patient may be having a stroke and should be transported to an appropriate facility quickly (See Figure 1).

If a patient has known deficits from a previous stroke, is under the influence of alcohol or substances, is hypoglycemic, is hypotensive, or has a history of neurological disorders, the results may not be as accurate. If a caregiver is present and can provide a baseline condition, it can be a valuable insight. Clinicians should proceed with caution, following all ACLS assessment algorithms to determine likely causes and possible diagnoses.

	Assessment	Normal Finding	Abnormal Finding
Facial Droop	Ask the patient to look up at you, smile, and show his/her teeth.	Both sides are symmetric, equal movement.	One side of the face droops or does not move the same.
Arm Drift	Have the patient lift both arms up and hold them out with eyes closed for 10 seconds.	Symmetrical movement in both arms.	One arm drifts down involuntarily; asymmetrical movement of the arms.
Abnormal Speech	Ask the patient to say, “You can’t teach an old dog new tricks.”	The correct words are used, and no slurring is noted.	The words are slurred, the wrong words are used, or the patient is unable to speak.

What CPSS Results Mean (and Don’t Mean)

It is important to know that the CPSS is not perfect, and it is a quick test designed to determine the probability of an acute ischemic stroke. It will not find every stroke, particularly those that affect only certain areas of the brain that are not assessed by the CPSS. These other strokes can likely be picked up by a more detailed assessment (such as the NIHSS). The NIHSS also includes a neuromuscular assessment, accompanied by a sensory ability assessment. The CPSS is also known to more accurately pick up anterior vessel strokes and be less likely to detect posterior vessel strokes. The test does not indicate the severity of a stroke. For this information, much more detailed assessment is needed as well as imaging studies, such as CT or MRI.

Stroke severity is usually classified using the AHA Stroke Outcome Classification Score (AHA SOC). This includes determining the level of impairment in the following neurological domains:

• Motor: Cranial nerve function including speech and swallow, muscle power and tone, reflexes, balance, gait, coordination, and apraxia.
• Sensory: Numbness, tingling, altered sensitivity, as well as more complex issues.
• Vision: Loss of vision on one or both sides, cortical blindness, partial vision loss.
• Language: Dysphagia, difficulty in comprehension, naming, writing, reading, fluency, and repetition.
• Cognition: Impairments in memory, attention, orientation, calculation abilities, and the ability to learn and retain new pieces of information.
• Affect: Depression, lack of expressiveness, loss of appetite, insomnia, and loss of energy.

You can see that there are a lot more detailed assessments that must be used when caring for a stroke patient. The value of the CPSS comes from rapidly finding stroke symptoms and transporting the patient to a hospital. Speed is emphasized because of the rapid rate at which brain damage occurs, and the fact that fibrinolytic therapy is only indicated (in most cases) within three hours after the onset of symptoms. Delays in treatment can mean lifelong disability and loss of function.

Conclusion

First responders of all types can safely learn and administer the CPSS. Clinicians equipped with this knowledge as well as ACLS certification are qualified to provide emergency care for almost any acute life-threatening clinical scenario. By rapidly responding to a new onset of symptoms, clinicians can be at the front line of providing life-saving stroke care and timely treatment that saves brain function.

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