What are the definition, relevant anatomy and physiology, etiology and pathophysiology, signs and symptoms, typical CVICU presentation, diagnosis, medical and nursing management, immediate nursing priorities, potential complications, red‑flag signs, and expected course/prognosis for acute ischemic stroke?

Acute Ischemic Stroke: Comprehensive CVICU Overview

Definition

Acute ischemic stroke (AIS) is a neurological emergency caused by vascular occlusion resulting in brain infarction, accounting for 85% of all stroke cases. 1

---

Relevant Anatomy and Physiology

• Cerebral blood flow depends on patent intracranial and extracranial vessels supplying oxygen and glucose to brain tissue 2
• Large vessel occlusions (internal carotid artery, middle cerebral artery, basilar artery) cause the most severe deficits and are targets for mechanical thrombectomy 2
• Collateral circulation determines the extent of salvageable penumbra surrounding the infarct core 2
• The blood-brain barrier becomes disrupted during ischemia, leading to cerebral edema and potential hemorrhagic transformation 3

---

Etiology and Pathophysiology

Primary Mechanisms

• Thrombotic occlusion from atherosclerotic plaque rupture in large or small vessels 3
• Cardioembolic sources including atrial fibrillation, acute myocardial infarction, valvular disease, and cardiomyopathy 3
• Small vessel (lacunar) disease from chronic hypertension and diabetes 3

Pathophysiological Cascade

• Arterial occlusion leads to immediate cessation of oxygen and glucose delivery 2
• Ischemic core develops within minutes with irreversible neuronal death 2
• Ischemic penumbra represents salvageable tissue that can survive for hours if reperfusion occurs 2
• Cerebral edema peaks at 24-72 hours and may cause life-threatening increased intracranial pressure (ICP) 3
• Hemorrhagic transformation can occur spontaneously or following reperfusion therapy 3

---

Signs & Symptoms

Neurological Deficits (depend on vascular territory)

• Hemiparesis or hemiplegia (contralateral to lesion) 3
• Facial droop (unilateral) 3
• Aphasia (dominant hemisphere involvement) 3
• Dysarthria (slurred speech) 3
• Visual field defects (homonymous hemianopsia) 3
• Ataxia and vertigo (posterior circulation) 3
• Altered level of consciousness (large hemispheric or brainstem strokes) 3
• Gaze deviation toward the lesion 3

Severity Assessment

• National Institutes of Health Stroke Scale (NIHSS) quantifies deficit severity: scores ≤5 indicate minor stroke, >20 indicate severe stroke 3, 4

---

Typical CVICU Presentation

Admission Scenarios

• Post-thrombolysis monitoring requiring BP control <180/105 mmHg for 24 hours 3
• Post-mechanical thrombectomy with risk of reperfusion injury, hemorrhage, and access site complications 3
• Large hemispheric infarction at risk for malignant cerebral edema 5
• Posterior circulation stroke with potential for brainstem compression and respiratory failure 5
• Failed reperfusion with progressive neurological deterioration 3

Initial Presentation Patterns

• Acute neurological deficit with NIHSS documentation on arrival 3
• Hemodynamic instability requiring vasopressor support in some cases 3
• Respiratory compromise from aspiration risk or brainstem involvement 3
• Cardiac arrhythmias including atrial fibrillation or acute coronary syndrome 3

---

Diagnosis & Evaluation

Immediate Imaging (within minutes of arrival)

• Non-contrast CT (NCCT) of the head is the first-line study to exclude hemorrhage and assess early ischemic changes 3, 2
• CT angiography (CTA) identifies large vessel occlusion for thrombectomy consideration 2
• CT perfusion or MRI with diffusion-weighted imaging may be used for extended-window decision-making (>4.5 hours from last known well) 2

Essential Laboratory Tests (do not delay reperfusion)

• Glucose (hypoglycemia can mimic stroke; hyperglycemia worsens outcomes) 3
• Complete blood count with platelets 3
• Coagulation studies (PT/INR, aPTT) if anticoagulation suspected 3
• Troponin and ECG to detect concurrent acute coronary syndrome 3
• Renal function (creatinine) for contrast administration 3

Additional Diagnostic Studies (after acute treatment decisions)

• Echocardiography (transthoracic or transesophageal) to identify cardioembolic sources 3
• Carotid Doppler ultrasound or CTA of neck vessels for extracranial stenosis 3
• Continuous cardiac monitoring for at least 24 hours to detect paroxysmal atrial fibrillation 3
• Chest radiography only if clinical suspicion of pulmonary or cardiac disease (should not delay treatment) 3

---

Interventions/Treatments: Medical and Nursing Management

Acute Reperfusion Therapy

Intravenous Thrombolysis

• Alteplase (rtPA) 0.9 mg/kg (maximum 90 mg) administered within 4.5 hours of symptom onset for disabling deficits 2, 6
• Pre-treatment BP must be <185/110 mmHg using labetalol 10-20 mg IV, nicardipine 5 mg/h IV (titrate by 2.5 mg/h every 5-15 min to max 15 mg/h), or clevidipine 1-2 mg/h IV (double dose every 2-5 min to max 21 mg/h) 3
• Post-thrombolysis BP target <180/105 mmHg for 24 hours 3
• Extended-window thrombolysis (4.5-9 hours) may be considered with advanced imaging selection 2, 6

Mechanical Thrombectomy (MT)

• Indicated for large vessel occlusion in anterior circulation within 24 hours of symptom onset (with appropriate imaging selection) 2, 6
• Posterior circulation strokes may have wider window up to 12-24 hours 5
• Can be performed with or without prior IV thrombolysis 2

Blood Pressure Management

For Thrombolysis Candidates

• Maintain BP <185/110 mmHg before treatment and <180/105 mmHg for 24 hours after 3
• Monitor BP every 15 minutes for 2 hours, then every 30 minutes for 6 hours, then hourly for 16 hours 3

For Non-Thrombolysis Patients

• Avoid routine BP lowering unless systolic BP ≥220 mmHg or diastolic BP ≥120 mmHg 7
• If treatment required, reduce by approximately 15% within 24 hours (avoid precipitous drops) 7

Glycemic Control

• Maintain glucose 140-180 mg/dL using IV insulin protocols 3
• Immediately treat hypoglycemia <60 mg/dL 3
• Avoid hyperglycemia >155 mg/dL 5

Temperature Management

• Treat fever >37.5°C promptly with antipyretics (first-line therapy) 3, 5
• Evaluate for infectious sources (pneumonia, urinary tract infection, sepsis) and non-infectious causes (central fever, PE, medications) 3
• Cooling devices may be considered for refractory fever 3
• Therapeutic hypothermia is NOT recommended for AIS 3

Oxygenation

• Maintain oxygen saturation >94% 3
• Supplemental oxygen only if hypoxic (routine oxygen therapy provides no benefit) 3
• Baseline lung sounds assessment and monitor for aspiration pneumonia 3

Venous Thromboembolism Prophylaxis

• Unfractionated heparin or low-molecular-weight heparin PLUS intermittent pneumatic compression should be initiated as soon as possible (provided no hemorrhagic complication) 3
• Risk of VTE is 75% without prophylaxis, with PE risk up to 20% in hemiplegic patients 3
• Early mobilization (timing varies by stroke severity and thrombolysis status; some recommend delaying 24 hours post-thrombolysis) 3

Dysphagia and Nutrition Management

• NPO status until swallow screen completed using evidence-based tool 3
• Formal swallowing assessment by speech-language pathology if screen abnormal 3
• Early enteral nutrition decreases mortality risk 3
• Head of bed elevation 15-30 degrees to prevent aspiration (exact angle determined by clinical condition) 3

Skin and Bowel/Bladder Care

• Comprehensive skin assessment with frequent repositioning and pressure-relieving mattress 3
• Minimize moisture and shear injury 3
• Investigate urinary retention, constipation, or incontinence (multifactorial causes in AIS) 3

Cardiac Monitoring

• Continuous telemetry for at least 24 hours to detect atrial fibrillation and arrhythmias 3
• Serial troponin and ECG if myocardial ischemia suspected 3
• Neurogenic cardiomyopathy can occur via neurohormonal pathways 3

---

Immediate Nursing Priorities

First Hour

1. Establish time of symptom onset (last known well) to determine reperfusion eligibility 2
2. Obtain NIHSS score to quantify deficit severity 3
3. Ensure NPO status until swallow screen performed 3
4. Initiate continuous BP and cardiac monitoring 3
5. Obtain IV access and draw essential labs (do not delay imaging) 3
6. Expedite neuroimaging (NCCT and CTA) 2

Post-Reperfusion Therapy

1. Intensive BP monitoring and control per protocol (every 15 min × 2 hours, then every 30 min × 6 hours, then hourly × 16 hours post-thrombolysis) 3
2. Frequent neurological assessments (every 15 minutes initially) to detect hemorrhagic transformation or clinical deterioration 3
3. Monitor for reperfusion complications: hemorrhage, cerebral edema, access site bleeding (post-MT) 3
4. Maintain oxygen saturation >94% 3
5. Check glucose every 4-6 hours and maintain 140-180 mg/dL 3

Ongoing Priorities

• VTE prophylaxis (pharmacological + mechanical) 3
• Temperature monitoring and prompt fever treatment 3
• Swallow screening before any oral intake 3
• Skin care and repositioning 3
• Early mobilization when appropriate 3

---

Potential Complications

Hemorrhagic Transformation

• Symptomatic intracerebral hemorrhage occurs in 4-29% of MT cases 3
• Risk increased with thrombolytic therapy, anticoagulation, and failed recanalization 3
• Presents as sudden neurological deterioration requiring emergent CT 3

Cerebral Edema and Increased ICP

• Malignant cerebral edema peaks at 24-72 hours, especially with large hemispheric infarcts 3, 5
• Signs: declining level of consciousness, pupillary changes, Cushing's triad 3
• Decompressive hemicraniectomy should be considered for malignant edema 5

Mechanical Thrombectomy Complications

• Vessel perforation or dissection leading to subarachnoid hemorrhage (worsened by recent thrombolysis) 3
• Embolization to new territory extending stroke 3
• Vasospasm, device detachment, or misplacement 3
• Access site complications: hemorrhage (including retroperitoneal), pseudoaneurysm, arterial closure device failure requiring emergent endarterectomy 3

Medical Complications

• Aspiration pneumonia from dysphagia 3, 8
• Venous thromboembolism (DVT/PE) in 75% without prophylaxis 3
• Cardiac complications: atrial fibrillation, acute myocardial infarction, congestive heart failure, neurogenic cardiomyopathy 3
• Fever from infection or central causes 3
• Hyperglycemia worsening outcomes 3
• Skin breakdown from immobility 3
• Urinary retention or incontinence 3

Recurrent Stroke

• Risk highest in first 90 days post-stroke 9
• Reperfusion therapy does NOT increase early recurrent stroke risk (5.5% EVT vs 4.5% medical management at 90 days) 9

---

Relevant Red Flags & CVICU Tips

Immediate Red Flags

• Sudden neurological deterioration → emergent CT to rule out hemorrhagic transformation or cerebral edema 3
• Declining level of consciousness → assess for increased ICP, hemorrhage, or seizure 3
• BP >180/105 mmHg post-thrombolysis → aggressive titration of IV antihypertensives required 3
• Hypoglycemia <60 mg/dL → immediate treatment (can mimic stroke worsening) 3
• Fever → workup for infection (pneumonia, UTI, sepsis) vs central fever 3
• Access site swelling or hypotension post-MT → assess for retroperitoneal hemorrhage or pseudoaneurysm 3

Critical CVICU Tips

• Do NOT routinely lower BP in non-thrombolysis patients unless ≥220/120 mmHg (permissive hypertension maintains cerebral perfusion) 7
• Avoid precipitous BP drops (target 15% reduction over 24 hours if treatment needed) 7
• Never give oral intake before swallow screen (aspiration risk is extremely high) 3
• Dual VTE prophylaxis (pharmacological + pneumatic compression) is superior to either alone 3
• Central fever is a diagnosis of exclusion (rule out infectious causes first) 3
• Therapeutic hypothermia has NO benefit in AIS (unlike cardiac arrest) 3
• Sodium nitroprusside is reserved for diastolic BP >140 mmHg unresponsive to other agents 3
• Comorbid conditions (acute coronary syndrome, heart failure, aortic dissection, preeclampsia) may require different BP targets 3

Monitoring Pearls

• NIHSS every 15 minutes initially to detect early deterioration 3
• Glucose checks every 4-6 hours (hyperglycemia and hypoglycemia both worsen outcomes) 3
• Continuous cardiac telemetry for at least 24 hours (atrial fibrillation may be paroxysmal) 3
• Neurological exam includes: level of consciousness, pupillary response, motor strength, speech, gaze 3

---

Expected Course and Prognostic Clues

Acute Phase (0-72 hours)

• Successful reperfusion (TICI 2b-3 recanalization) predicts better functional outcomes 2
• Early neurological improvement within 24 hours suggests favorable prognosis 2
• Cerebral edema peaks at 24-72 hours in large infarcts 3
• Hemorrhagic transformation most common in first 24-48 hours 3

Subacute Phase (3-7 days)

• Medical complications (pneumonia, DVT/PE, cardiac events) emerge 3, 8
• Early mobilization and rehabilitation begin (if no contraindications) 3, 8
• Dysphagia assessment and nutritional optimization 3

Recovery Phase (1 week to 3 months)

• Functional recovery varies widely based on infarct size, location, and reperfusion success 2
• Minor strokes (NIHSS ≤5) can still result in disability in up to 30% at 90 days 4
• Recurrent stroke risk highest in first 90 days (but NOT increased by reperfusion therapy) 9
• Secondary prevention (antiplatelet therapy, anticoagulation for cardioembolic sources, statin, BP control) initiated during hospitalization 4, 6

Prognostic Factors

• NIHSS score: higher scores predict worse outcomes 3
• Age: advanced age associated with poorer recovery 3
• Time to reperfusion: shorter times predict better outcomes 2
• Infarct volume: larger infarcts have worse prognosis 2
• Successful recanalization: TICI 2b-3 flow predicts better functional independence 2
• Complications: hemorrhage, malignant edema, pneumonia, and cardiac events worsen prognosis 3

Long-Term Outcomes

• Specialized stroke unit care saves lives, reduces disability, and shortens length of stay 8
• Interdisciplinary approach with nursing, physical therapy, occupational therapy, speech therapy, and social work optimizes recovery 8
• Malnutrition (prevalence 6-62%) is an independent predictor of morbidity and mortality 3