What is the protocol for managing a patient with ST-Elevation Myocardial Infarction (STEMI)?

STEMI Management Protocol

The management of ST-Elevation Myocardial Infarction (STEMI) requires immediate reperfusion therapy, preferably with primary percutaneous coronary intervention (PCI) within 90 minutes of first medical contact, or fibrinolysis if PCI cannot be performed within this timeframe. 1

Initial Assessment and Immediate Actions

1. Immediate Assessment (First 10 minutes)

   • Obtain 12-lead ECG within 10 minutes of first medical contact 1
   • Administer chewable aspirin 162-325 mg immediately 1
   • Establish IV access 1
   • Administer oxygen only if saturation <90% 1
   • Continuous cardiac monitoring 2

2. Medication Administration

   • Antiplatelet therapy:
     • Aspirin 162-325 mg (chewed) 1
     • P2Y12 inhibitor: Ticagrelor 180 mg or prasugrel 60 mg loading dose (preferred) or clopidogrel 600 mg if others unavailable 1, 3
   • Anticoagulation: Unfractionated heparin 70-100 U/kg IV bolus 1
   • Symptom management:
     • Sublingual nitroglycerin if systolic BP >90 mmHg 1
     • Morphine 5-10 mg IV for pain (with antiemetic if needed) 1
   • Beta-blockers: Early administration if no contraindications 1

Reperfusion Strategy Decision

Primary decision point: Time to PCI availability

1. Primary PCI available within 90 minutes of first medical contact:

   • Preferred strategy, especially for patients with contraindications to fibrinolysis or cardiogenic shock 1
   • Immediate transfer to cardiac catheterization laboratory 2
   • Avoid GP IIb/IIIa inhibitors routinely upstream before primary PCI 1

2. Primary PCI not available within 90 minutes:

   • Administer fibrinolytic therapy within 10 minutes of STEMI diagnosis 1
   • Consider tenecteplase (weight-adjusted dose) 4
   • Contraindications to fibrinolysis include: active internal bleeding, history of cerebrovascular accident, intracranial surgery/trauma within 2 months, intracranial neoplasm/AVM/aneurysm, bleeding diathesis, severe uncontrolled hypertension 4
   • Transfer to PCI-capable facility after fibrinolysis 1

Critical Care Management

1. Monitoring and Environment

   • Admit to quiet environment with continuous ECG and pulse oximetry monitoring 2
   • Ensure access to hemodynamic monitoring and defibrillation equipment 2
   • Nursing care by critical care certified staff 2

2. Medication Management

   • Review medication regimen to ensure appropriate aspirin and beta-blocker dosing 2
   • Assess need for IV nitroglycerin for angina, hypertension, or heart failure 2
   • Consider insulin infusion to normalize blood glucose, especially in complicated cases 2
   • Correct documented magnesium deficits 2

3. Complication Management

   • Ventricular arrhythmias: Have anti-arrhythmic therapy available 1
   • Ventricular septal rupture: Diagnose with echocardiography and color Doppler; urgent surgical repair indicated 1
   • Cardiogenic shock: Consider intra-aortic balloon counterpulsation 1
   • Bleeding complications: Discontinue anticoagulants and antiplatelet agents if serious bleeding occurs 4

Post-STEMI Care

1. Medication Regimen

   • Dual antiplatelet therapy for 12 months 1
   • ACE inhibitors within 24 hours for anterior STEMI, heart failure, or EF ≤0.40 1
   • High-intensity statin therapy for all patients 1
   • Aldosterone antagonist for patients with EF ≤0.40 and symptomatic heart failure or diabetes 1

2. Triage and Transfer

   • Low-risk STEMI patients who have undergone successful PCI can be admitted directly to stepdown unit 2
   • Transfer patients from CCU to stepdown unit after 12-24 hours of clinical stability 2
   • Allow limited mobility after 12-24 hours if no recurrent ischemia, heart failure, or serious arrhythmias 2

Common Pitfalls to Avoid

• Do not delay reperfusion therapy while waiting for laboratory results 1
• Do not administer fibrinolytics to patients with contraindications or when primary PCI is readily available 1
• Do not administer intravenous ACE inhibitors within first 24 hours due to risk of hypotension 2
• Do not administer routine IV magnesium in the absence of documented deficits 2
• Do not use diltiazem or verapamil in patients with LV dysfunction or heart failure 2
• Do not use immediate-release nifedipine due to risk of reflex sympathetic activation 2
• Avoid intramuscular injections and nonessential handling during first few hours after fibrinolytic therapy 4

This protocol provides a comprehensive approach to STEMI management with the primary goal of achieving rapid reperfusion to reduce mortality and improve quality of life outcomes.