Nursing Care Plan for Myocardial Infarction (MI)

Initial treatment for acute coronary syndrome.

• Morphine: given ONLY if aspirin and nitroglycerin do not relieve chest pain. Initial dose is 2-4 mg IV.
• Oxygen: helps for you to remember to check oxygenation for chest pain – if under 94% or if patient is short of breath give 2L NC initially. Administer oxygen only when clinically relevant.
• Nitroglycerin: This is the initial medication given, along with aspirin. This medication dilates the blood vessels to help allow any blood flow that might be impeded. Give 0.4 mg sublingual tab, wait 5 minutes, if the chest pain is not relieved administer another dose. This can happen 3 times total. Monitor a patient’s blood pressure, hold for a systolic BP of less than 90 mmHg.
• Aspirin: given to thin the blood and decrease mortality risk. A total of 4 baby aspirin (81 mg each) can be given for a total of 324 mg, or a single 325 mg dose.

Assess a 12 lead ECG immediately on anyone complaining of chest pain to determine if an ST elevated MI is occurring. If it is-Take the patient to the cath lab STAT! If the ECG is a normal sinus or otherwise non-concerning rhythm, place them on a 3 or 5 lead cardiac monitor for frequent re-assessing.

Right sided 12 lead ECG shows the right side of the heart to assess for right ventricular ischemia. **Inferior MI’s need to be treated differently!**

No matter the outcome of the 12 lead ECG, placing a patient on a form of cardiac monitoring is key. You are worried about a worsening condition such as cardiac arrest.

A patient who has an ST elevated MI (STEMI) will be rushed to the cath lab so they can locate the clot and place a stent to regain blood flow to the heart.

A patient may also go to the cath lab without having a STEMI, and they may still find a clot. Most NON-STEMI’s are treated without catheterization.

This is important because the higher the blood pressure, the more pressure is on a clot. It isn’t out of the question for someone to have more than one clot, and increased pressure could break free a clot lodge itself somewhere else either in the heart, lungs, brain, or extremity.

This is an anticoagulant that prevents clots. 

• Monitor aPTT or Anti-Xa Q6H to adjust and maintain therapeutic levels.

For STEMI

• Bolus: 60 units/kg (max 4,000 units)
• Continuous infusion: 12 units/kg/hr
• -Adjust according to your organization’s nomogram (Q6H- based on results of aPPT or Anti-Xa)

For N-STEMI

• Bolus: 60-70 units/kg (max 5,000 units)
• Continuous Infusion: 12-15 units/kg/hr
• -Adjust according to your organization’s nomogram (Q6H- based on results of aPPT or Anti-Xa)

IV access is important for administration of medications, possible interventions if angina worsens, and any scans that may be needed to rule out thrombosis.

Cardiac enzymes further serve to rule out Myocardial Infarction and can give an indication to the extent of myocardial damage.

• Troponin I
• CK
• CK-MB
• Myoglobin

The values of these enzymes are based on your institutional laboratory technique. If they are elevated it indicates that the cardiac muscle is stressed out or injured.

• Troponin I is an enzyme that helps the interaction of myosin and actin in the cardiac muscle. When necrosis of the myocyte happens, the contents of the cell eventually will be released into the bloodstream.
  • Troponin can become elevated 2-4 hours after in ischemic cardiac event and can stay elevated for up to 14 days.
• Creatine Kinase MB: This enzyme is found in the cardiac muscle cells and catalyses the conversion of ATP into ADP giving your cells energy to contract. When the cardiac muscle cells are damaged the enzyme is eventually released into the bloodstream.
  • CKMB levels should be checked at admission, and then every 8 hours afterwards.