What are the steps to assess for stroke and when to call 911 (Emergency Medical Services)?

How to Assess for Stroke and When to Call 911

Immediate activation of emergency medical services (911) is essential when any signs of stroke are recognized, as rapid assessment and treatment within the first few hours of symptom onset are critical for reducing mortality and morbidity from stroke.

Recognizing Stroke Signs and Symptoms

The FAST method is a validated tool to identify potential stroke symptoms:

• F - Face: Ask the person to smile. Look for facial droop or asymmetry on one side 1
• A - Arms: Ask the person to raise both arms. Look for one arm drifting downward or inability to raise one arm 1
• S - Speech: Ask the person to repeat a simple phrase. Listen for slurred words, incorrect words, or inability to speak 1
• T - Time: Note when symptoms began and call 911 immediately if any of these signs are present 1

Additional stroke warning signs include:

• Sudden numbness or weakness, especially on one side of the body 1
• Sudden confusion or trouble understanding 1
• Sudden trouble seeing in one or both eyes 1
• Sudden trouble walking, dizziness, or loss of balance/coordination 1
• Sudden severe headache with no known cause 1

When to Call 911

Call 911 immediately if you observe ANY of the following:

• Any single FAST sign (facial droop, arm weakness, or speech abnormality) 1
• Any of the additional stroke warning signs listed above 1
• If you're unsure but suspect stroke, err on the side of calling 911 1

The presence of even a single abnormality on the Cincinnati Prehospital Stroke Scale (CPSS/FAST) has a 72% probability of indicating stroke 1.

What Happens After Calling 911

1. Emergency medical dispatchers should recognize stroke symptoms and assign high priority response 1
2. EMS personnel will perform stroke assessment using validated tools 1
3. EMS will determine time of symptom onset (critical information) 1
4. They will provide rapid transport to an appropriate stroke center 1
5. Pre-arrival notification to the hospital will be made 1

Critical Time Factors

• Fibrinolytic therapy administered within the first hours of symptom onset significantly improves outcomes 1
• The treatment window is extremely limited, making rapid recognition and EMS activation essential 1
• Time of symptom onset is crucial information for treatment decisions 1

Common Pitfalls to Avoid

• Delay in calling 911: Many people wait to see if symptoms resolve, significantly reducing treatment options 1
• Driving yourself or having someone drive you: This delays treatment and prevents pre-hospital notification 1
• Failing to note the exact time when symptoms began: This critical information affects treatment eligibility 1
• Mistaking stroke for other conditions: When in doubt, call 911 - it's better to err on the side of caution 1
• Incomplete symptom recognition: The FAST method may miss some stroke symptoms, particularly for hemorrhagic strokes (missing up to 30.6% of hemorrhagic cases) 2

Special Considerations

• Family members should accompany patients when possible to verify symptom onset time and provide consent for interventional therapy 1
• Stroke patients are at risk for respiratory compromise; supplementary oxygen may be needed for those with oxygen saturation <94% 1
• The Cincinnati Prehospital Stroke Scale identifies stroke patients with reasonable sensitivity and specificity 1

Remember that immediate action is critical - "Time is Brain" - and every minute delay in treatment increases the risk of permanent disability or death 1.