Rapid Reviews

Essential Protocols for ACS and AIS Management

Topic Overview

The Certified Emergency Nurse (CEN) exam heavily emphasizes time-sensitive, protocol-driven care for patients experiencing Acute Coronary Syndrome (ACS) and Acute Ischemic Stroke (AIS). These are high-volume, high-risk clinical presentations where rapid assessment, standardized interventions, and management of complications directly correlate to patient morbidity and mortality. Mastery of the latest American Heart Association (AHA) and emergency nursing core competencies is essential for both exam success and clinical safety. ^[3]

1. Acute Coronary Syndrome (ACS) Rapid Review

Key Concepts & Definitions

• STEMI (ST-Elevation Myocardial Infarction): Complete occlusion of a coronary artery. EKG shows hallmark ST-segment elevation. Requires immediate reperfusion (PCI or fibrinolysis).
• NSTEMI (Non-ST-Elevation MI): Partial occlusion or transient total occlusion. EKG shows ST-depression or T-wave inversion. Elevated cardiac troponin. Managed with antiplatelet/anticoagulant therapy and early invasive strategy.
• Unstable Angina (UA): No elevation in cardiac biomarkers. EKG may be normal or show non-specific changes. Represents acute plaque rupture without complete occlusion.

Core Assessment Protocol (Door-to-EKG < 10 Minutes)

• Primary Survey: Airway, Breathing, Circulation (ABCs). Assess chest pain (PQRST: Provocation, Quality, Radiation, Severity, Timing).
• Focused History: Onset of pain, associated symptoms (SOB, nausea, diaphoresis, imminent doom), past medical history (CAD, DM, HTN), and risk factors (smoking, hyperlipidemia).
• 12-Lead EKG: Must be obtained and interpreted within 10 minutes of arrival. This is a critical quality metric for STEMI care. ^[1]
• Laboratory Studies: High-Sensitivity Cardiac Troponin (hs-cTn) drawn at 0 and 3 hours (or serial). Chemistry panel, CBC, INR, PTT.
• Imaging: Portable Chest X-ray (to rule out pneumothorax, dissection, or pneumonia as causes of pain).

Key Interventions (AHA 2023 ACLS Guidelines)

• Oxygen: Administer only if SpO₂ is < 90% or patient is in respiratory distress. Routine oxygen in normoxic patients may be harmful. ^[1]
• Aspirin (ASA): Administer 162-325 mg chewed immediately. This is the cornerstone of antiplatelet therapy.
• Nitroglycerin (NTG): 0.4 mg SL q5min up to 3 doses for ongoing chest pain. Contraindicated: Hypotension (SBP < 90 mmHg), severe bradycardia, or suspected Right Ventricular (RV) infarction. Always assess for prior use of PDE-5 inhibitors (sildenafil, tadalafil) within 24-48 hours. ^[5]
• Morphine: Administer 2-4 mg IV push cautiously for refractory pain. De-emphasized in current guidelines due to risk of respiratory depression and hypotension compared to other options. ^[1]
• Anticoagulation / Antiplatelet Therapy: Unfractionated Heparin, LMWH, or bivalirudin + P2Y12 inhibitors (ticagrelor, prasugrel, clopidogrel) depending on initial management strategy (invasive vs. conservative).
• Reperfusion: PCI is the preferred method. Door-to-Balloon time should be < 90 minutes. If PCI is unavailable, fibrinolytic therapy should be initiated within 30 minutes of arrival. ^[1]

Safety & Complications

• Dysrhythmias: Ventricular fibrillation (V-fib) is the most lethal complication. Ensure defibrillator is immediately available. Monitor for reperfusion dysrhythmias (e.g., accelerated idioventricular rhythm).
• Hypotension: Rule out RV infarction (needs fluids, NOT nitrates). Consider cardiogenic shock (signs: JVD, pulmonary edema, poor perfusion).
• Bleeding: High risk due to aggressive antiplatelet/anticoagulation therapy. Monitor puncture sites (femoral/radial), assess for occult GI or intracranial bleeding.

2. Acute Ischemic Stroke (AIS) Rapid Review

Key Concepts & Definitions

• Ischemic Stroke: Occlusion of a cerebral artery by a thrombus or embolus. Accounts for ~87% of strokes.
• Hemorrhagic Stroke: Rupture of a blood vessel (intracerebral or subarachnoid). Requires immediate reversal of any anticoagulation and neurosurgical consultation. tPA is contraindicated.
• Last Known Well (LKW): The single most important time point determining eligibility for acute reperfusion therapies (tPA and thrombectomy).

Core Assessment Protocol (Door-to-CT < 20 Minutes)

• Pre-hospital Screening: Cincinnati Prehospital Stroke Scale (CPSS) or LAMS.
• Primary Survey/Stabilization: ABCs, establish IV access, draw labs (PT/INR, PTT, CBC, BMP, Glucose), check vital signs. Rule out hypoglycemia (a stroke mimic).
• Stroke Assessment: Use the National Institutes of Health Stroke Scale (NIHSS) to quantify the severity of the neurological deficit. ^[2]
• Urgent Imaging: Non-contrast CT head is the gold standard to differentiate ischemic from hemorrhagic stroke. CT Angiography (CTA) may be used to identify large vessel occlusion (LVO) for potential thrombectomy.

Key Interventions (AHA/ASA 2021/2023 Guidelines)

• Airway Management: Maintain SpO₂ > 94%. Intubation only if GCS < 8 or unable to protect airway.
• Blood Pressure Management:
  • No tPA: Permissive hypertension is allowed (SBP up to 220 mmHg, DBP up to 120 mmHg). ^[2]
  • tPA Candidate: BP must be meticulously lowered and maintained to **SBP < 185 mmHg** and **DBP < 110 mmHg** prior to tPA administration. Labetalol and Nicardipine drips are commonly used.
• Reperfusion Therapy (tPA Alteplase / Tenecteplase):
  • Window: Up to 4.5 hours from LKW. ^[2]
  • Dose (Alteplase): 0.9 mg/kg (max 90 mg). Give 10% as bolus over 1 minute, remaining 90% as infusion over 60 minutes.
  • Monitoring: Strictly monitor for bleeding. Neuro checks q15min during infusion. No aspirin or anticoagulants for 24 hours post-tPA.
• Mechanical Thrombectomy: Gold standard for LVO (M1, ICA, basilar). Window is 6-24 hours based on advanced imaging (CT Perfusion/MRI). ^[2]

Complications & Safety

• Intracranial Hemorrhage (ICH): The most feared complication of tPA. Signs: worsening headache, acute hypertension, vomiting, new focal deficit, decreased LOC. Stop tPA immediately and obtain stat CT head.
• Angioedema: Orolingual swelling (often contralateral to the side of stroke). Treat with Diphenhydramine, Famotidine, and Methylprednisolone. May require airway intervention.
• Dysphagia: ALL stroke patients must be NPO until a formal swallow screen is completed. Silent aspiration is common. ^[3]
• Hemorrhagic Conversion: Ischemic strokes can naturally transform into hemorrhagic strokes. Monitor for sudden deterioration.

3. High-Yield Exam Tips & Memory Aids

Critical Contraindications (Testing Favorites)

Must-Know Door-to-Treatment Timelines

• Door-to-EKG (ACS): < 10 minutes.
• Door-to-Balloon (PCI for STEMI): < 90 minutes. ^[1]
• Door-to-Needle (tPA for Stroke): < 60 minutes (goal is 45 mins). ^[2]
• Door-to-CT (Stroke): < 20 minutes.
• Time Window for tPA: 0-4.5 hours from LKW.

Rapid Differential Diagnosis

• Stroke Mimics: Hypoglycemia, seizure (Todd's paralysis), complex migraine, electrolyte imbalances. Always check a finger-stick glucose! ^[3]
• Chest Pain Mimics: Aortic dissection (tearing pain, BP differential, wide mediastinum on CXR), Pulmonary Embolism (pleuritic pain, dyspnea, hypoxia), Pericarditis (positional, diffuse ST-elevation on EKG).

References & Sources

1. Panchal, A. R., Bartos, J. A., Cabañas, J. G., Donnino, M. W., Drennan, I. R., Hirsch, K. G., ... & Lavonas, E. J. (2023). 2023 American Heart Association and American Red Cross Focused Update on Advanced Cardiovascular Life Support and First Aid. Circulation. https://doi.org/10.1161/CIR.0000000000001131
2. Powers, W. J., Rabinstein, A. A., Ackerson, T., Adeoye, O. M., Bambakidis, N. C., Becker, K., ... & Tirschwell, D. L. (2019). Guidelines for the Early Management of Patients With Acute Ischemic Stroke: 2019 Update to the 2018 Guidelines. Stroke, 50(12), e344–e418. https://doi.org/10.1161/STR.0000000000000211
3. Emergency Nurses Association. (2021). Core Curriculum for Emergency Nursing (8th ed.). ENA. https://shop.ena.org/collections/books/
4. Centers for Disease Control and Prevention. (2023). STEMI and NSTEMI: Heart Attack Case Definitions for Public Health Surveillance. https://www.cdc.gov/heartdisease/definitions.htm
5. Lewis, S. M., Bucher, L., Heitkemper, M. M., & Harding, M. M. (2022). Medical-Surgical Nursing: Assessment and Management of Clinical Problems (11th ed.). Elsevier. https://doi.org/10.1016/C2020-0-03480-0