Stroke: Issues for Prehospital Providers
Ischemic stroke is a leading cause of morbidity and mortality in the United States, with approximately 700,000 strokes occurring each year. The cost is staggering, with an estimated $23 billion-plus spent annually on the care of these patients.
Prehospital response to patients suffering from strokes is a regular occurrence. Unfortunately, these people are not always managed with the same aggressiveness as other patients with life-threatening emergencies. But there are numerous ways to better prepare care for stroke patients – and your organization can also play a role in decreasing the number of strokes in your community.
Stroke is an acute brain injury that is caused by the interruption or reduction of blood flow to the brain. This condition is called a cerebrovascular accident (CVA). An estimated 80-85 percent of strokes are the result of arterial occlusions, which can be caused by clot formations, narrowing of blood vessels and changes to the lining of blood vessels supplying the brain.
Clot formations impairing circulation to the brain can also develop in other locations in the body. Patients with deep vein thrombosis or atrial fibrillation can have an emboli, or clot, which can travel to the brain and subsequently decrease blood flow to it. As the blood flow decreases, it results in a smaller supply of oxygen and glucose to the affected regions of the brain.
The remaining 15-20 percent of CVAs are caused by hemorrhage, which is the result of the rupture of a blood vessel that supplies an area of the brain. For those suffering from a subarachnoid hemorrhage, an estimated 10-15 percent die before reaching the hospital. Of those patients who do survive to-hospital admission, 40 percent do not make it through the first week.
CVA vs. TIA
When discussing strokes, it's important to understand the difference between a CVA and a transient ischemic attack (TIA). Both a CVA and TIA refer to the altered neurological deficits affecting the brain. If the deficits last longer than 24 hours, regardless of whether they are resolved shortly afterward, it is referred to as a CVA or stroke. If the deficits are resolved within 24 hours, it is referred to as a TIA. This can resolve itself within the time EMS personnel are with the patient. In fact, up to 80 percent of TIA symptoms are resolved within one hour. However, the TIA is a significant medical event and the patient needs to be evaluated at a medical facility. Patients who have a TIA are at a 30 percent increased risk for having a stroke within the subsequent five years.
There are a number of risk factors that may predispose a person to having a stroke. Some of these are:
- Age. People 60 years and older face increased risk of stroke, with instances peaking between the ages of 80-84.
- Hypertension. For each 10mm Hg increase in systolic blood pressure, or 5mm Hg increase in diastolic blood pressure, the risk of stroke increases by a risk factor of 2.3. Some research suggests that approximately 50 percent of all strokes can be eliminated with the control of hypertension.
- History of atrial fibrillation can increase the change for a stroke by a risk factor of five. This is why it is important not to cardiovert a patient in atrial fibrillation if the condition has existed for more than 48 hours.
- History of a previous TIA
- Diabetes increases the relative risk by two.
- Cigarette smokers have a four to six-fold increase of stroke compared to non-smokers.
- Gender. Overall stroke rates are 1.25 times greater in men than women.
- Race. There are higher incidents and mortality rates in African-American, Asians, Pacific Islanders and Hispanic-Americans when compared to Caucasians.
- Time. Most calls to EMS for a patient suffering from a stroke come from the patient's family or friend. This increase in time decreases the likelihood of a positive outcome. Also some do not contact EMS if symptoms of a TIA resolve quickly, which can impact future care.
A patient can present to responders in a number of various ways, depending on the cause of the CVA and the vessel that is occluded. These can include:
- Sudden numbness or weakness of face, arm, or leg (monoparesis or hemiparesis)
- Sudden confusion, trouble speaking (aphasia, dysphasia, or dysarthria), or difficulty understanding
- Sudden difficulty seeing in one or both eyes, including loss of vision or double vision
- Sudden difficulty walking, dizziness, or loss of balance and coordination, including limb ataxia
- Sudden severe headache. When present, headache may occur several days prior to onset of other symptoms
- Sudden decline in level of consciousness (may include fainting, confusion, convulsions, or coma)
- Rapid onset of nausea and vomiting
- Facial droop
There are two excellent assessment tools for EMS providers to quickly assess and identify stroke and TIA in the majority of patients, with the first being the Cincinnati Prehospital Stroke Scale. If any three of the signs are abnormal, the probability of a stroke (either ischemic or hemorrhagic) is 72 percent. The second is the Los Angeles Prehospital Stroke Screen (LAPSS), and is regarded as a more accurate and in-depth of screening tool. If all five screening criteria are checked yes or unknown, and if any three of the exam categories are checked, then there is a 93 percent possibility that the patient is having a stroke. Both of these tools can only be used to identify acute, nontraumatic and noncomatose patients. It's important to bear in mind that these are also tools, so therefore are not 100 percent accurate. A patient may not meet all the criteria and still be having a stroke.
CINCINNATI PREHOSPITAL STROKE SCREEN
- Facial Droop (have patient smile)
- Normal Both sides of face move equally
- Abnormal One side of face does not move as well as the other side
- Arm Drift (patient closes eyes and hold both arms out straight for 10 seconds)
- Normal Both arms move the same or both arms do not move at all
- Abnormal One arm does not move or one arm drifts down
- Abnormal Speech (have patient say "you can't teach an old dog new tricks")
- Normal Patient uses correct words with no slurring
- Abnormal Patient slurs words, uses wrong words, or is unable to speak
LOS ANGELES PREHOSPITAL STROKE SCREEN (LAPSS)
|1. Age over 45 years||___||___|
|2. No prior history of seizure disorder||___||___|
|3. New onset of neurologic symptoms in last
|4. Patient was ambulatory at baseline (prior
|5. Blood glucose between 60 and 400||___||___|
|Exam: look for obvious asymmetry|
|Facial smile / grimace:||__||__ Droop||__ Droop|
|Grip:||__|| __ Weak Grip
__ No Grip
|__ Weak Grip
__ No Grip
|Arm weakness:||__|| __ Drifts Down
__ Falls Rapidly
|__ Drifts Down
__ Falls Rapidly
|6. Based on exam, patient has only unilateral
If Yes (or unknown) to all items above LAPSS screening criteria met:
If LAPSS criteria for stroke met, call receiving hospital with "code stroke." If not then return to the appropriate treatment protocol. (Note: the patient may still be experiencing a stroke even if LAPSS criteria are not met.)
Treatment for stroke involves thrombolytic therapy. This can only properly be done in the hospital. There is a narrow window for treatment to take place, and that requires prehospital providers to take quick and rapid action.
Things that are important for prehospital providers to do in the field include:
- As with all patients, assess the airway, breathing and circulation. Stroke patients may have difficulty in maintaining an airway.
- Begin oxygen therapy on any patient with hypoxia. Monitor patient with pulse oximetry.
- Do a neurological exam. Use a proven exam like the Cincinnati Prehospital Stroke Screen or Los Angeles Prehospital Stroke Screen to assess the patient.
- Determine the time of onset of symptoms. This information is critical to the receiving hospital as the use of thrombolytic therapy has a narrow therapeutic timeframe.
- Check patient's blood sugar. Hypoglycemia can cause the patient to present with stroke symptoms.
- Establish a baseline 12 lead ECG to determine any arrhythmias.
- Establish in IV route but do not give dextrose containing fluids such D5W.
- Update the receiving Emergency Department so their staff can prepare for the patient's arrival and begin therapeutic efforts.
- Transport the patient as soon as possible. Certain medications that will be administered in the hospital have a small window of effectiveness.
Things NOT to do:
- Do not delay transport. Speed is vital for the most optimal patient outcome.
- Do not forget to note the onset of stroke symptoms. This information is vital for hospital providers.
- Start an IV, but do not give large amounts of fluid. Large amounts of fluids may worsen the patient's condition.
- Do not give dextrose, unless the patient is hypoglycemic.
The responsibility to prehospital providers includes prevention, as well as response. As people across the country lose their health care, they will need someone to help them learn how to prevent illness. Some researchers have determined that 50 percent of all strokes can be eliminated by effective control of hypertension. The simple assessment of taking and recording a person's BP, as well as referring them for treatment for hypertension, can make a significant difference in reducing strokes. A regular blood pressure screening for high-risk groups should be a consideration for any EMS agency.
- Responding to stroke patients is a medical emergency. Time is of the essence.
- Develop your checklist for quick patient assessment.
- Have a stroke assessment tool readily available and ensure that it is consistently used system-wide.
- Strokes last longer than 24 hours, and a TIA is when symptoms last less than 24 hours. Even when TIAs resolve themselves quickly, they are still a medical emergency.
- Do not give dextrose unless needed for hypoglycemia.
- Your responsibility includes helping to prevent illness. Prevention programs can successfully help decrease the risks to stroke.
Prehospital providers need to understand the importance of responding and treating stroke patients.