Learning Objectives
By the end of this section, you will be able to:
- Discuss the pathophysiology, risk factors, and clinical manifestations for ischemic stroke
- Describe assessment and diagnostics in ischemic stroke
- Apply nursing concepts and plan associated nursing care for the patient with an ischemic stroke
- Evaluate the efficacy of nursing care for the patient with an ischemic stroke
- Describe the medical therapies that apply to the care of the patient with an ischemic stroke
An ischemic stroke is when the obstruction of blood flow in the brain is caused by an occlusion in a vessel, most commonly by atherosclerotic fatty deposit build-up. About 87 percent of all strokes are ischemic (American Stroke Association, 2023). An ischemic stroke requires different initial care than a hemorrhagic stroke, mainly because the primary cause is a clot rather than a bleed from a vessel within the brain. Though the initial treatment differs, the roles of the nurse and the rest of the interdisciplinary care team can have many similarities in the later stages of treatment and care.
Pathophysiology
In thrombosis, an obstructive process prevents blood flow to regions of the brain. The most common risk factor is large vessel atherosclerosis. An ischemic stroke is most commonly caused by the fatty deposits, or plaques, found collecting on the lining of the vessel walls, seen in patients with atherosclerosis. These deposits can form a cerebral thrombus, which is essentially a clot within a blood vessel that blocks cerebral perfusion. Alternately, the clot preventing perfusion could be a cerebrovascular embolus, which forms elsewhere in the body (such as the heart or carotid arteries), breaks off, and travels to the blood vessels of the brain. The embolus then gets lodged in a smaller vessel in the brain and prevents perfusion, causing a cerebral embolism. Such embolisms most commonly form in the left atrium of the heart in patients with atrial fibrillation, a heart dysrhythmia discussed in Chapter 12 Cardiovascular System (American Stroke Association, 2023).
Ischemic strokes fall into four categories: large artery thrombosis, small artery thrombosis, cardiogenic embolism, and cryptogenic. A large artery thrombosis is a plaque occlusion of blood flow in a larger vessel. The larger vessels responsible for cerebral perfusion are the basilar artery, the middle cerebral artery (MCA), and the carotids in the neck. A small artery thrombosis, often referred to as a lacunar stroke, occurs in the small arteries in the brain that branch off from the larger vessels. These can be caused by high cholesterol, atherosclerosis, diabetes, or high blood pressure.
Cardiogenic strokes are those caused by clots traveling into the brain from the heart. Some common cardiac conditions that cause emboli to form are arrythmias such as atrial fibrillation, valvular heart disease such as endocarditis, prosthetic heart valves, recent myocardial infarction, and some ventricular diseases. Another common cause is the presence of a patent foramen ovale, a small hole between the left and right atria to support fetal circulation; the hole usually closes on its own, but it remains open after birth for 25 percent of the population (American Heart Association, 2023). A cardiogenic embolus may occur due to cholesterol accumulation, platelets or other blood clots, calcium, or accumulated bacteria. Such emboli can enter systemic circulation and travel throughout the body. However, more than 80 percent of such clots travel to the brain (Pillai et al., 2022).
The final type of ischemic stroke is a cryptogenic stroke. A cause cannot be determined for this type of stroke, regardless of testing done to identify the common causes. Studies have reported an increased incidence of cryptogenic stroke among African Americans and Hispanics (American Stroke Association, 2023).
Though it is not a type of stroke, transient ischemic attack (TIA) deserves mention. Often referred to as a “mini-stroke,” a TIA is caused by an occlusion of the blood vessels perfusing parts of the brain, just like a full stroke. The difference is that in a TIA, the clot dislodges or dissolves on its own, restoring perfusion before any permanent damage to the brain can occur. It can cause the same symptoms as a full stroke and symptoms can last from minutes up to twenty-four hours; however, there is no permanent loss of function. A “mini-stroke” is dangerous because it usually indicates that a full stroke will occur: The 90-day stroke risk after a TIA is almost 18 percent (Amin et al., 2023). It is important to determine the cause of a TIA so the condition can be treated, thereby decreasing the risk of a full stroke.
Life-Stage Context
Older Adults and Risk for Stroke
Age-related changes are associated with increases in systolic blood pressure readings but do not have the same effects on the diastolic blood pressure readings. Isolated systolic hypertension is the most common type of hypertension in adults over the age of fifty. Isolated systolic hypertension is associated with increased risk of stroke. Older adults should begin treatment with lifestyle modifications.
(Tan & Thakur, 2023)
Clinical Manifestations
The clinical manifestations of an ischemic stroke can vary depending on which area of the brain is not being well perfused; another factor is the size of the clot impairing perfusion. In general, the symptoms of large vessel strokes present very suddenly. A patient with a large artery ischemic stroke may have weakness or paralysis on one side of the body, a loss of sensation to one side of the body, visual changes, problems with balance or coordination, issues with word-finding, or aphasia. A small vessel, or lacunar, stroke generally causes one-sided deficits: facial droop, weakness or paralysis in the arm or leg, impaired or complete loss of sensation, and ataxia. It may also manifest with dysarthria. The symptoms of a small vessel stroke often appear more gradually than a large vessel stroke, and deficits are often fewer because the small vessels perfuse a smaller area of the brain. Larger vessels are responsible for delivering blood to a larger region of the brain, so the symptoms can be greater.
A patient with an ischemic stroke may present with other symptoms, too, including vertigo or dizziness, neck stiffness, memory loss, confusion, or even nausea and vomiting. In fact, dizziness and vertigo are the most common symptoms in a missed stroke diagnosis. The presentation of a stroke can vary and be nonspecific. The most important thing to know is that brain cells die within minutes of not receiving adequate oxygen through cerebral perfusion, so early recognition and intervention are essential for reducing poor outcomes.
Assessment and Diagnostics
Stroke assessment is based on subjective data, but it is also important to conduct a complete neurological assessment, which is objectively rated using the National Institutes of Health Stroke Scale (NIHSS). The NIHSS also is a prognosticator: Lower scores generally predict a more devastating stroke. Subjectively, the most important question you can ask is, “When were you last seen acting normal?” This data is imperative since stroke onset is considered to be when the patient was “last known well,” or without symptoms; treatments to save brain tissue and function are time-sensitive. Other subjective data include a health history, focusing on diseases (such as diabetes mellitus and hypertension) and lifestyle factors (such as nicotine use and use of certain oral contraceptives) that may increase stroke risk; providers should also ascertain whether the patient had previous strokes or TIAs. The objective neurological assessment involves five areas: cognition, cranial nerves, motor function, sensory function, and gait. A complete neurological exam will reveal deficits used to help localize the area of the brain affected, and then the NIHSS will be used to determine the severity and prognosis of the stroke.
Diagnostics and Laboratory Values
The diagnostic imaging for stroke begins with a STAT head CT without contrast dye. This CT is done to determine whether a bleed in the brain is present, signifying a hemorrhagic stroke rather than an ischemic stroke. The treatment of a hemorrhagic stroke is very different from the treatment of an ischemic stroke, so the results of the CT will allow the provider to decide on a treatment plan.
Diagnostic studies after the initial head CT are focused on determining the location, size, and impact of the infarct, or area of necrosis, formed by the interruption in perfusion. Diagnostic studies can also provide details to find the cause of the stroke. If a cause can be identified, measures can be taken to reduce the risk of a subsequent stroke.
To view the impact of the infarction on the brain, magnetic resonance imaging (MRI) is essential. An MRI with diffusion-weighted imaging (DWI) allows visualization of not only ischemia related to stroke but identifies the penumbra, the brain tissue that has been hypoperfused as a result of the occlusion but is not yet ischemic. The DW-MRI may be done right after the initial head CT to further determine the course of treatment.
Subsequent diagnostic imaging will be conducted to help reveal the cause of the stroke by first looking at the vasculature. This may include a computed tomography angiography (CTA), a magnetic resonance angiography (MRA), angiography, or ultrasonography. MRAs and CTAs are noninvasive scans that provide a view of the vessels within the brain and neck and allow vascular abnormalities, such as occlusions and stenoses, to be visualized. A CTA is a more sensitive test than an MRA, but it is less widely available and requires the patient to receive an intravenous iodinated contrast dye. A cerebral angiography requires a catheter be inserted into the patient, usually through the femoral artery, and considerable amounts of contrast dye, but it provides detailed images of blood flow. Finally, ultrasonography is much less invasive. These tests can be completed at bedside; they allow for visualization of the carotids but not the vessels within the brain.
A stroke “work-up” aimed at identifying the cause of the stroke includes an electrocardiogram or telemetry monitoring, as well as a transthoracic or transesophageal echocardiogram (TEE). To help identify abnormalities in the heart’s rhythm (namely atrial fibrillation) or structure anomalies (primarily a patent foramen ovale), laboratory studies include but may not be limited to the following:
- complete blood count (CBC) and basic metabolic panel (BMP) to analyze platelets and electrolyte levels;
- prothrombin time (PT), international normalized ratio (INR), partial thromboplastin time (PTT), and clotting factor Xa to measure clotting times because a patient with prolonged clotting times may not be eligible for tPA due to bleeding risk;
- thyroid-stimulating hormone (TSH) levels because hyperthyroidism increases the risk of developing atrial fibrillation and thus increases stroke risk;
- blood glucose levels because hypoglycemia symptoms can mimic stroke symptoms; diabetes is a risk factor for stroke, so hemoglobin A1C levels will be tested to assess average three-month glucose control;
- lipid blood test or cholesterol panel to check for high cholesterol;
- erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) to look for inflammation; and
- D-dimer test, which can indicate an increased clotting risk.
The assessment, diagnostic tests, and laboratory tests that assist in the identification of an ischemic stroke also detail the extent of the stroke, identify the brain tissue that can potentially be saved, and help determine the cause of the stroke. The reason that the stroke work-up is so labor intensive is that identifying the cause of a stroke assists in the collaborative efforts of the interdisciplinary team to treat the stroke and employ preventive actions to minimize the risk for another stroke.
Nursing Care of the Patient with Ischemic Stroke
A nurse is caring for a hospitalized patient in a medical-surgical unit. The nurse performs their morning assessment of the patient and notices several findings that are not within normal limits. Let’s read on to see how the nurse uses clinical judgment in this situation.
Recognizing and Analyzing Cues
On assessment, the nurse first recognizes the following cues: the patient’s face is drooping on the left side, the patient’s speech is slurred, and the patient does not appear to be moving their left arm as well as their right arm when the nurse is assessing range of motion.
The nurse analyzes the cues, recognizing facial droop is related to cranial nerve VII and that slurred speech is called dysarthria. The patient clearly understands what is being said, but is unable to respond by speaking clearly. Finally, by assessing the patient’s strength in both arms, the nurse can rate the strength of the right arm 5/5 but the left arm only 4/5. The nurse recognizes these three cues as neurological changes consistent with stroke warning signs.
Prioritizing Hypotheses, Generating Solutions, and Taking Action
The nurse analyzes the cues to determine the source of neurological changes, hypothesizing different rationales for signs and symptoms. After determining that the patient is having an acute stroke, the nurse prioritizes interventions for immediate action. When generating solutions, the nurse knows patient safety is most important. The nurse calls for the emergency stroke response to be activated at the facility. Larger hospitals may alert the specific stroke or neurology providers who respond immediately to the emergency; the protocol at smaller hospitals may be to call the rapid response team and notify the attending who is covering the patient. To ensure safety, the nurse does the following:
- positions the patient’s head, neck, and body in proper alignment to aid in perfusion and prevent airway compromise
- applies supplemental oxygen per facility protocol
- initiates NPO status to reduce the risk of aspiration
- obtains vital signs to check the patient for adequate oxygenation and perfusion
- prepare and educates the patient for what may come next, such as preparing for transport to diagnostic imaging areas, obtaining two large IVs, and getting an accurate weight for weight-based tPA administration.
Clinical Safety and Procedures (QSEN)
QSEN Competency: Safety
Disclaimer: Always follow the agency’s policy for medication administration.
Definition: Minimizes risk of harm to patients and providers through both system effectiveness and individual performance. The nurse will . . .
Skill: Demonstrate effective strategies to reduce the risk of harm to self or others.
Attitude: Value the contributions of standardization/reliability to safety. Patients suspected of having a stroke should be made NPO right away because one of the major stroke impairments is dysphagia.
- The patient should remain NPO until a trained nurse or speech–language pathologist can perform a swallow screen using an evidence-based tool.
- Swallowing should be evaluated to identify dysphagia and prevent aspiration before any PO food, fluids, or medications are given.
Evaluation of Nursing Care for the Patient with Ischemic Stroke
Evaluation is a critical component of the nursing process. Through evaluation, the nurse can assess the effectiveness of their interventions and modify their actions to help reach the desired outcome or solution that they generated.
Evaluating Outcomes
In the previously described scenario, the nurse focused on patient outcomes related to maintaining safety and optimizing the patient’s prognosis status by initiating prompt interventions. The nurse’s actions of initiating an emergency stroke response, focusing on patient safety (e.g., NPO status, proper body alignment to facilitate the best possible oxygenation and cerebral perfusion), and preparing the patient for the next steps in the stroke work-up aided in the speedy diagnosis and treatment of an ischemic stroke. Recovery from a CVA, however, is not instantaneous; residual deficits may be identified months after the initiation of rehabilitation. Thus, “recovery” in the acute care phase of stroke treatment cannot be used as an indicator of long-term outcomes.
Medical Therapies and Related Care
Initial or emergency stroke treatment focuses on reversing brain ischemia and initiating successful reperfusion. The subsequent treatment of ischemic stroke focuses on two areas: preventing subsequent strokes and minimizing the effects of long-term disability.
Thrombolytics
Only one kind of drug is used to treat ischemic stroke by dissolving the clot to restore perfusion: tissue plasminogen activator (tPA). Medications in this class are alteplase and tenecteplase. Treatment must be administered within 3–4.5 hours of stroke onset or “last known well” to be effective at reversing brain ischemia. This medication is given intravenously after a hemorrhage has been ruled out by head CT (because a thrombolytic agent could make a hemorrhage worse). The American Heart Association has set a door-to-needle time (meaning the time between when the patient arrives to an emergency department to the time tPA is administered) of 60 minutes or less in at least 85 percent of patients (American Heart Association, 2019).
The major risk associated with tPA is bleeding, particularly intracranial hemorrhage. Because of this bleeding risk, there are conditions that would make the patient ineligible for tPA treatment. The excluding factors include:
- oral anticoagulation therapy (INR > 1.7, PT > 15 seconds, or a PTT > 40 seconds)
- platelet count < 100,000/mm3
- previous ischemic stroke or head trauma in the past three months
- gastrointestinal bleeding within the last 21 days
- intracranial or spinal surgery within the past three months
- persistent high blood pressure (systolic ≥ 180 mmHg or diastolic ≥ 110 mmHg)
- confirmed active internal bleeding
- infective endocarditis, or abnormal cardiac rhythms
- aortic arch dissection
- pregnancy or recent C-section
Other important considerations prior to tPA administration are ruling out hypoglycemia as the cause for symptoms, ensuring two large-bore (such as eighteen gauge) intravenous lines are in place, and obtaining an accurate weight for the patient since the tPA dose is weight-based (Oliveira-Filho & Samuels, 2023). After receiving tPA, the patient is closely monitored for at least twenty-four hours in an ICU or stroke-dedicated unit. Care is comprised of cardiac monitoring, routine neurological assessment, and frequent vital signs checks. During that time, the patient’s blood pressure must be controlled to ≤ 180/105. It is necessary to obtain another CT or MRI twenty-four hours after tPA to rule out intracranial bleeding prior to starting antiplatelet or anticoagulant therapies.
Thrombectomy
Another treatment for ischemic stroke is a mechanical thrombectomy. This procedure essentially involves a catheter inserted through a vessel (commonly in the groin) to physically remove the clot from the cerebral artery. A thrombectomy is used only for large artery occlusions and must be done within twenty-four hours of stroke onset or “last known well.” Clots occluding small arteries are too difficult to reach. A thrombectomy can be done with or without concurrent tPA treatment.
Link to Learning
Review the current guidelines for clinical management of patients diagnosed with an ischemic stroke from the American Heart Association/American Stroke Association.
Continued Ischemic Stroke Management
After the initial treatment with tPA or a thrombectomy, or when a patient presents outside of the respective care windows, treatment is aimed at preventing subsequent strokes and minimizing the effects of long-term disability.
Blood pressure management is very important after a stroke. High blood pressure is almost always noted in patients with ischemic strokes. Most times, after the removal of a clot with tPA or thrombectomy, the brain still relies on a higher systemic blood pressure for reperfusion of the ischemic penumbra. To sustain the perfusion, the patient is initially allowed to maintain a higher blood pressure, called permissive hypertension. The systolic goal is < 160–180 mmHg for patients who have received tPA, but it may be even higher (up to 220/120) for those who did not receive tPA. Control within these parameters may require intravenous administration of labetalol or nicardipine. Reduction in blood pressure begins twenty-four to forty-eight hours after stroke intervention, at which time antihypertensive medications will be resumed or started.
An aspirin regimen should be started for stroke patients. Aspirin’s antiplatelet effects help improve circulation. It is typically given orally but can be administered rectally to patients with impaired swallowing or whose swallowing ability has not yet been evaluated. The initial or loading dose is 325 mg, followed by daily treatment of 81 mg. Dual antiplatelet therapy is often a treatment for patients. Dual therapy adds clopidogrel: a loading dose of 300–600 mg, followed by 75 mg daily. Antiplatelet therapy continues for twenty-one days for smaller strokes and ninety days for larger strokes.
Hyperlipidemia is a major cause of atherosclerosis and thus stroke. Laboratory results commonly show elevated cholesterol and low-density lipoprotein levels in ischemic stroke patients. Pharmacotherapy, such as statin therapy, reduces the risk of subsequent strokes and is most often administered in the form of atorvastatin (80 mg daily).
Managing blood glucose is another way to reduce risk of subsequent stroke. The risk for stroke increases for patients with diabetes mellitus, particularly females. Patients with diabetes are more likely to have carotid atherosclerosis, which can impair cerebral perfusion. Glycemic control can be achieved through any combination of insulin, oral drugs, diet, and exercise to reach a goal of A1C ≤ 7 percent (Oliveira-Filho & Mullen, 2023). Education should also be provided regarding modifiable and nonmodifiable risk factors (Table 15.3).
| Type of Risk Factor | Factors |
|---|---|
| Modifiable | Alcohol consumption Atrial fibrillation Cardiac disease Diabetes mellitus Hyperlipidemia Hypertension Obesity Physical inactivity Sleep apnea Smoking Unhealthy diet |
| Nonmodifiable | Age (older adults at greater risk) Family history Prior stroke or TIA Race/ethnicity (Black and Hispanic/Latinx populations at greater risk) Sex (females have more strokes than males) |
Complications during acute stroke may include risks for falls, aspiration, pressure injury, and venous thromboembolism. Complications specific to neurologic function are the risks for hemorrhagic transformation of the stroke, cerebral edema, and seizure. Hemorrhagic transformation is when a hemorrhagic infarct occurs after ischemic stroke; this risk increases after the administration of tPA. The health-care team needs to monitor closely for changes indicative of these complications, such as increased or new neurological deficits and changes in Glascow Coma Scale (GCS), and implement strategies to prevent them. A hemorrhagic transformation occurs when blood vessels in the brain rupture after reperfusion; this is usually within twenty-four hours for patients who received tPA or had a thrombectomy or within the first few days for untreated patients.
Other interdisciplinary team members who may be part of a patient’s continued ischemic stroke treatment are physical, occupational, speech language, and recreational therapists. These professionals help with regaining muscle movement, strength, and control, as well as increased independence with ADLs and coping, confidence building, and improving socialization skills. They also help with learning to live with the disabilities that may result from stroke. Sometimes a patient may need to relearn or develop alternative strategies for daily activities and actions, such as safe movement and transfers, dressing, bathing, speech, swallowing, and higher-level thinking involved with activities like grocery shopping or playing card games. Therapists help make those adjustments. A neuropsychologist or other therapist may help with the effects on a patient’s cognition and mental health. A nutritionist or dietician may teach the patient about foods that interact with new medications or help reduce cholesterol. A pharmacist may help the patient understand new medications. A social worker or case manager may be involved to help with placement in a rehabilitation facility or to orchestrate home nursing and therapy services after discharge. There are many people across a variety of specialties who are involved in continued stroke care and whose job it is to reduce long-term disability and the risk of future stroke in their patients.
Prevention
The primary stroke prevention recommendations by the American Heart Association/American Stroke Association are to stop cigarette smoking, increase physical activity, maintain a healthy weight, and control cholesterol, blood pressure, and diabetes. Risk factors that should be managed are atrial fibrillation, obstructive sleep apnea (OSA), migraine with aura, sickle cell disease, and hypercoagulable states (e.g., COVID-19, cancer). Finally, efforts to end alcohol or drug abuse should be initiated (Tai, 2022).