4. Stroke An Educational Program for Pre-Hospital Personnel Developed by: EMS Committee Operation Stroke – American Stroke Association Phoenix, Arizona July 2003
56. NINDS-Recommended Stroke Evaluation Targets for Potential Fibrinolytic Candidates* *Target times will not be achieved in all cases, but they represent a reasonable goal. † CT indicates computed tomography. ‡ By phone or in person. Time Target 3 hours Admit to monitored bed 2 hours Access to neurosurgical expertise ‡ 15 minutes Access to neurological expertise ‡ 60 minutes Door to treatment 45 minutes Door to CT read 25 minutes Door to CT † completion 10 minutes Door to doctor
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Editor's Notes
The following presentation is taken from the American Heart Association’s Advanced Cardiac Life Support: Principles and Practice, Chapter 18, Acute Stroke: Current Treatments and Paradigms. Please use this publication as a reference.
Until recently care of the stroke patient was largely supportive, with therapy focusing on treating respiratory and cardiovascular complications of the stroke. Because little therapy was directed toward altering the course of the stroke itself, little emphasis was placed on rapid transport or intervention.
Now, however, fibrinolytic and other emerging therapies (such as neuroprotective agents, which are not available at this time but show promise in early studies) offer practitioners the opportunity to limit neurological insult and improve outcome in stroke patients. The challenge with these therapies is that they require administration within 3 hours of stroke onset, making the following measures imperative: Education of at-risk patients Early recognition of stroke signs Prompt transport to the hospital Rapid hospital triage and evaluation
Definition of Stroke: A stroke is a neurological impairment caused by a disruption in blood supply to a region of the brain.
Classification of Stroke: Strokes can be classified into two major categories: Ischemic strokes - Occur because a blood vessel supplying the brain is occluded. Hemorrhagic strokes - Occur because a cerebral artery ruptures. Although both forms can be life threatening, ischemic stroke rarely leads to death within the first hour, whereas hemorrhagic stroke can be fatal at onset. Even among those who survive the first few hours after a stroke, brain injury progresses quickly and can lead to permanent disability. The classification of stroke as ischemic or hemorrhagic is important because management of the two differs markedly.
Hemorrhagic Stroke: The most common cause of a subarachnoid hemorrhage is an aneurysm. Arteriovenous malformations account for approximately 5% of all subarachnoid hemorrhages. Hypertension is the most common cause of intracerebral hemorrhage.
Although some strokes occur without warning, most stroke victims have prior risk factors.The best way to prevent a stroke is to identify at-risk patients and, once they are identified, control as many risk factors as possible. Some risk factors can be eliminated (eg, smoking), controlled (eg, high blood pressure, diabetes mellitus), or treated (eg, by antiplatelet therapy or carotid endarterectomy) to reduce the risk of stroke. Some rather low-level risk factors become significant when combined with other risk factors. For example, oral contraceptives and cigarette smoking together increase the risk of stroke considerably in young women. At-risk patients should receive aggressive education to increase their knowledge about stroke, its risk factors, and its signs and symptoms.
Well-documented modifiable risk factors and less-well documented modifiable risk factors recently published by Goldstein et al. Circulation. 2001:103:163 __________________________________ Hypertension - Major risk factor for both cerebral infarction and intracerebral hemorrhage. The incidence of stroke increases in proportion to both systolic and diastolic blood pressure. Smoking - Active (current) smoking has been long recognized as a major risk factor for stroke. Diabetes - Insulin-dependent diabetics have both an increased susceptibility to atherosclerosis and an increase prevalence of atherogenic risk factors, notably hypertension, obesity, and abnormal blood lipids. Carotid Stenosis - Frequently, patients with severe (>75%) carotid artery stenosis, progressing carotid artery stenosis, or heart disease have increased chance of stroke. Atrial Fibrillation –Aggressive treatment of atrial fibrillation is an important way to help prevent stroke. Hyperlipidemia - Management of patients with elevated cholesterol decreases risk of stroke. Sickle Cell Disease and other cardiac diseases - Modifiable risk factors using appropriate preventative treatment.
Non-modifiable Risk Factors: Age - Age is the single most important risk factor for stroke worldwide. In persons past the age of 55 years, the incidence of stroke increases for both men and women. However, it is important to note that stroke is not just a disease of the elderly; a quarter of all stroke victims are younger than 65. Sex - Men are at greater risk for stroke than women. However, since more women than men live beyond the age of 65 years, more women than men older than 65 actually die of stroke each year. Race/Ethnicity - African Americans have more than twice the risk of death and disability from stroke than whites. Much of this risk can be explained by the greater number of risk factors present in African Americans (eg, smoking, high blood pressure, sickle cell anemia, high cholesterol, and diabetes). Family History - Risk of stroke is greater for people who have a family history of stroke, but this risk is probably complicated by the presence of multiple common risk factors in families (eg, smoking, high blood pressure). The risk of stroke for someone who has already had a stroke is many times that of someone who has not. Recurrent stroke risk is highest within the first 30 days after a stroke, and long-term risk of recurrence averages 4% to 14% per year.
The warning signs of an ischemic stroke or transient ischemic attack (TIA) may be subtle or transient, but they foretell a potentially life-threatening neurological illness. Typical signs and symptoms of anterior and posterior-circulation strokes are presented in this presentation. Emergency healthcare providers should recognize the importance of these symptoms and respond quickly with medical or surgical measures of proven efficacy in stroke prevention.
Reference: Heartsaver CPR: A Comprehensive Course for the Lay Responder: 2000 American Heart Association
THIS IS A LIFE THREATENING EMERGENCY! Emergency healthcare providers should recognize the importance of these symptoms and respond quickly with medical or surgical measures of proven efficacy in stroke prevention.
Hemorrhagic strokes may present similar to ischemic strokes.
Transient Ischemic Attack: A TIA is a reversible episode of focal dysfunction of the brain or vision that is secondary to transient occlusion of an artery. The signs and symptoms of a TIA are similar to those of a completed stroke; however, they typically last only a few minutes to several hours before resolving. The patient who experiences a TIA usually presents to medical personnel with a normal neurological exam, so that the diagnosis is often based on history alone.
TIA is the most important forecaster of brain infarction. Approximately 5% of patients with TIAs will develop a cerebral infarction within the first month. The risk increases to 12% at 1 year and an additional 5% for every year after that. Evaluation to determine the likely cause of TIA and institution of appropriate treatment can significantly reduce the risk of stroke. Carotid endarterectomy is of proven benefit among patients with recent TIA who have a severe (>70%) narrowing of the origin of the internal carotid artery. Oral anticoagulants are usually prescribed to prevent embolism to the brain in patients with cardiac causes of stroke, particularly those with atrial fibrillation.
Optimal care of the stroke victim of acute stroke must minimize delay in recognition of stroke symptoms, activation of the EMS system, rapid transport to and pre-arrival notification of a hospital capable of acute stroke care, appropriate evaluation and selection of eligible candidates (if applicable) for fibrinolytic therapy, and administration of fibrinolytics. Delays at any of these major points can increase the the negative outcome of the stroke patient – to include making them ineligible for fibrinolytic therapy. Begin tPA treatment within 3-hour time limit Drug Patient remains candidate for tPA therapy? If “yes,” then: - Review risks and benefits with patient and family - Obtain informed consent for tPA therapy Decision CT scan Serial neurologic exams Review for tPA exclusions Review patient data Date Immediate general and neurologic assessment in the ED Aim or predefined evaluation targets Door Transportation, with prearrival notification, to receiving hospital Provision of appropriate prehospital assessment and care Delivery Activation of the EMS system and prompt EMS response Dispatch Early recognition – onset of stroke signs and symptoms Detection Major Actions
1. Detection Surveys completed within major metropolitan areas found that less than 20% of those asked could name numbness or weakness of one side of the body as a stroke warning sign. All other warning signs were even less known. Public education is an essential part of any strategy to ensure timely access to care for stroke victims. It has been successful in reducing the time to arrival in the emergency department.
2. Dispatch Stroke victims and their families must be taught to activate the EMS system as soon as they detect stroke signs or symptoms. Currently only half of stroke victims use the EMS system despite the fact that this system provides the safest and most efficient method for transporting the patient to the hospital. Although highly skilled dispatchers can be effective in triaging emergencies over the telephone, additional education about stroke is required. In a recent study, just over half of the EMS dispatchers correctly diagnosed stroke from the initial EMS call. Contact with the EMS system not only enables the dispatch of trained providers but also puts the victim or family members in contact with someone who can provide emergency information. EMS dispatchers can instruct bystanders in lifesaving skills, such as airway management, positioning of the patient, and rescue breathing, while EMS personnel are en route.
3. Delivery Rapid identification of the stroke Support of vital functions Rapid transport of the victim to the receiving facility Pre-arrival notification of the receiving facility EMS providers must be effectively trained in the recognition and treatment of stroke. EMS system protocols must assign a high priority to stroke patients. In most EMS systems, stroke patients are treated under a generic "altered mental status" protocol. Stroke must be suspected quickly by EMTs and paramedics in the field. In one study EMTs and paramedics correctly identified stroke and TIA in 72% of the patients with either condition. Training must incorporate protocols that cover early recognition, early stabilization, early transportation, and early notification of the receiving facility. Extensive medical histories and neurological exams by pre-hospital personnel are impractical, especially because gathering this data may delay transport to the ED.
The Cincinnati Pre-hospital Stroke Scale, named for the location it was developed, identifies a high percentage of acute stroke patients by assessing only 3 physical findings: Facial Droop Arm Drift Speech
This evaluation can be done in less than one minute. Patients with one of the three findings – as a new event – have a 72% probability of a stroke; if all 3 findings are present, the probability of an acute stroke is more than 85%. Immediately contact medical control providers and the destination ED and provide prearrival notification. These patients require rapid transport to the hospital.
Once the diagnosis of stroke is suspected, time in the field must be minimized. The presence of acute stroke is an indication for "load and go" because there is limited time to institute therapy, and newer therapies can be provided only in the emergency department of the receiving hospital. A more extensive examination or institution of supportive therapies can be accomplished en route to the hospital and in the emergency department. If possible, prehospital providers should establish the time of onset of stroke signs and symptoms. This timing will have important implications for potential therapy. If the time of onset of symptoms is viewed as time "zero," all assessments and therapies can be related to that time. Early notification of emergency department personnel has always played a critical role in emergency cardiac care and trauma systems. Early notification enables personnel to prepare for the imminent arrival of any seriously ill or injured patient. In many hospitals this notification shortens the time to evaluation of, and critical interventions for, stroke patients.
Airway: Paralysis of the muscles of the throat, tongue, or mouth can lead to partial or complete upper-airway obstruction. Saliva pools in the throat and may be aspirated. Vomiting occurs, particularly with hemorrhagic stroke, and aspiration of vomitus is a concern. Frequent suctioning of the oropharynx or nasopharynx is required. Supplemental oxygen can be administered according to the needs of the patient. Tracheal or bronchial obstruction can occur in stroke patients. Paramedics may need to provide endotracheal intubation in the field when basic airway management is ineffective. Comatose patients are at particular risk for upper-airway obstruction and often require endotracheal intubation. Exercise caution in moving the neck if there is a possibility of cervical trauma. Most patients with stroke will be able to relate a history of recent injuries, but this information may be unavailable for a comatose patient. Infrequently a patient will have a stroke in conjunction with a head or neck injury, or the patient will fall with the onset of stroke and have a secondary cervical injury. In such cases the neck should not be hyperextended or the patient turned until a firm cervical collar is in place.
Breathing: Breathing abnormalities are uncommon, except in patients with severe stroke, and rescue breathing is seldom needed. Abnormal respirations, however, are prominent in comatose patients and portend serious brain injury. Irregular respiratory rates include prolonged pauses, Cheyne-Stokes respirations, or neurogenic hyperventilation. Shallow respirations or inadequate air exchange resulting from paralysis can also occur. Rescue breathing, assisted ventilation, and supplemental oxygen may be helpful.
Circulation: Cardiac arrest is an uncommon complication of stroke and usually follows respiratory arrest. Very few stroke patients will require chest compressions. Cardiovascular disturbances, on the other hand, are frequent, and monitoring of both blood pressure and cardiac rhythm is part of the early assessment and treatment of a stroke patient. Hypotension or shock is rarely due to stroke, so other causes should be sought.
Hypertension is often present in stroke patients, but it typically subsides and does not require treatment. Treatment of hypertension in the field is not recommended. Decisions about this therapy should be made in the emergency department, where blood pressure can be monitored continuously. Cardiac arrhythmias may point to an underlying cardiac cause of stroke or may be a consequence of the stroke. Bradycardia may indicate hypoxia or elevation of ICP.
Isotonic fluids (Normal Saline or Lactated Ringer's solution) are used for intravenous therapy; hypotonic fluids are contraindicated. Glucose-containing solutions should be avoided unless hypoglycemia is documented by rapid glucose test or is strongly suspected from history. Bolus administration of fluids is not indicated unless hypovolemia is present. Pulse, respirations, and blood pressure should be checked frequently so that changes or abnormalities can be detected. Disturbances in these signs are frequent.
4. Door Hospitals should notify community EMS services whether they have the equipment and personnel to manage patients with acute stroke. Some hospitals use "Code Stroke" or assemble a specific "stroke team" or prepare a designated "stroke unit" to organize personnel and equipment and evaluate and care for the stroke patient as efficiently as possible. This efficiency is maximized through the use of checklists, standing orders, and protocols.
Level of Consciousness : Determining the stroke patient's level of consciousness is crucial. Depressed consciousness within hours of onset of stroke implies a severe brain insult with increased ICP, usually from an intracerebral or subarachnoid hemorrhage. Early stupor or coma is uncommon with nonhemorrhagic strokes although it may occur with massive hemispheric or brain stem infarction. Type of Stroke : (Hemorrhagic versus nonhemorrhagic) Histories and physical findings of hemorrhagic and ischemic stroke overlap, and emergency personnel should not depend solely on the clinical presentation for diagnosis. In most cases, a noncontrast CT scan is the definitive test for differentiating ischemic from hemorrhagic stroke. Location of Stroke : In alert patients with brain infarction, higher cortical, language, visual, cranial nerve, motor, and sensory functions should be assessed. The neurological signs help distinguish carotid infarction from infarction of the vertebrobasilar distribution. Severity of Stroke : The National Institutes of Health Stroke Scale (NIHSS) measures neurological function that correlates with stroke severity and long-term outcome in patients with ischemic stroke. It was designed to provide a reliable, valid, and easy-to-perform alternative to the standard neurological examination for patients with ischemic stroke.
Diagnostic studies ordered in the emergency department are aimed at establishing stroke as the cause of the patient's symptoms, differentiating brain infarction from brain hemorrhage and determining the most likely cause of the stroke.
Noncontrast CT scan is the most important diagnostic test for an acute stroke. On CT images blood from a hemorrhagic stroke has a density that is only about 3% greater than the density of brain tissue. On modern CT scanners this 3% difference in density can be manipulated so that the hemorrhage and free blood will appear distinctly white in comparison with surrounding tissue. During the first few hours of a thrombotic or embolic stroke, the noncontrast CT scan will generally appear normal. Brain structures without normal blood flow appear initially the same as structures with good blood flow on the CT scan. For this reason the CT scan will continue to appear “normal” for a few hours after blood flow is blocked or reduced to an area of the brain. A well-defined area of hypodensity, purported to be caused by a lack of blood flow past an occlusion, will rarely develop within the first 3 hours of a stroke.
Several conditions mimic stroke. Frequent alternative diagnoses include unrecognized seizures, confusional states, syncope, toxic or metabolic disorders, including hypoglycemia, brain tumors, and subdural hematoma. These mimics are commonly, but not always, associated with global findings rather than focal neurological symptoms and are usually readily detected with standard laboratory tests.
7. Drugs All patients presenting within 3 hours of the onset of signs and symptoms consistent with an acute ischemic stroke should be considered for intravenous fibrinolytic therapy. These are the current AHA recommendations for management of acute stroke: Give t-PA intravenously (0.9 mg/kg, maximum 90 mg), with 10% of the dose given as a bolus followed by an infusion lasting 60 minutes. Treatment must be initiated within 3 hours of the onset of ischemic symptoms, tPA cannot be recommended for a person who has had a stroke more than 3 hours earlier, except in an investigational setting. Intravenous tPA is not recommended when the time of stroke onset cannot be ascertained reliably, including strokes recognized on awakening.
The use of fibrinolytic agents carries the real risk of major bleeding. Whenever possible, the risks and potential benefits of tPA should be discussed with the patient and the patient's family before treatment is initiated. Use caution when treating people with severe stroke or early CT changes of a recent major cerebral infarction (eg, sulcal effacement, mass effect, or edema) because these findings are associated with an increased risk of hemorrhage following tPA administration. The AHA recommendations for treatment of bleeding complications include the following: Fibrinolytic therapy should not be used unless facilities that can handle bleeding complications are readily available. Bleeding is considered the likely cause of neurological worsening after use of a fibrinolytic drug. CT should be obtained on an emergency basis. The following steps should be taken when any life-threatening hemorrhagic complication (including intracranial bleeding) occurs: Discontinue the infusion of fibrinolytic drug Obtain blood for coagulation tests Obtain neurosurgical consultation as necessary Consider transfusion, cryoprecipitate, and platelets
Three hours was chosen as the upper limit for treating acute stroke patients with IV tPA because that was the time window in the NINDS trial and the FDA used the NINDS protocol to define the upper limit of 3 hours. The NINDS investigators chose 3 hours because prior studies had raised concerns about the safety of giving tPA beyond 3 hours. The fibrinolytic protocol should address the following issues: Identification of patients with stroke in the prehospital setting Assurance of prearrival hospital notification Development and maintenance of rapid triage and medical evaluation in the emergency department Development of a mechanism for rapidly obtaining a noncontrast head CT Identification of who will read the CT Determination of contraindications to fibrinolytic therapy Location of fibrinolytic drugs and determination of how they will be mixed Designation of who will administer drug Consultation for atypical cases or hemorrhagic complications Determination of where the patient will be admitted
The National Institute of Neurological Disorders and Stroke (NINDS) study group has recommended timed goals for the evaluation of stroke patients who are candidates for fibrinolytic therapy. The purpose of these targets or goals is to suggest a timeline that provides a specific evaluation level for 80% of patients with acute stroke.
Hemorrhage into the brain can be a devastating condition, causing collapse or sudden development of a focal neurological deficit. Death may occur because of compression or distortion of vital, deep brain structures or increased ICP. Optimal management relies on the prevention of continued bleeding, appropriate management of ICP, and timely neurosurgical decompression when warranted. Large intracerebral or cerebellar hematomas often require surgical intervention.
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