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Myocardial Infarction- Medical Surgical management, thrombolytics, ACE-I, PTCA, Angioplasty

MEDICAL MANAGEMENT

PHARMACOLOGIC THERAPY

The patient with an acute MI receives the same medications as the patient with unstable angina, with the possible additions of thrombolytics, analgesics, and angiotensin-converting enzyme (ACE) inhibitors.

Thrombolytics

Indications

• Chest pain for longer than 20 minutes, unrelieved by nitroglycerin

• ST-segment elevation

Absolute Contraindications

• Active bleeding

• Known bleeding disorder

• Recent major surgery or trauma

• Uncontrolled hypertension

• Pregnancy

Nursing Considerations

• Minimize the number of times the patient’s skin is punctured.

• Avoid intramuscular injections.

• Draw blood for laboratory tests when starting the IV line.

• Start IV lines before thrombolytic therapy.

• Avoid continual use of noninvasive blood pressure cuff.

• Check for signs and symptoms of bleeding

•Treat major bleeding by discontinuing thrombolytic therapy and any anticoagulants; apply direct pressure and notify the physician immediately.

The thrombolytic agents used most often are streptokinase(Streptase), alteplase (Activase) and reteplase (r-PA, TNKase).

Analgesics

The analgesic morphine sulfate administered in IV boluses. Morphine reduces pain and anxiety. It reduces preload, which decreases the workload of the heart. Morphine also relaxes bronchioles to enhance oxygenation.

Angiotensin-Converting Enzyme Inhibitors (ACE-I)

Prevent the conversion of angiotensin from I to II. In the absence of angiotensin II, the blood pressure decreases and the kidneys excrete sodium and fluid (diuresis), decreasing the oxygen demand of the heart. Blood pressure, urine output, and serum sodium, potassium, and creatinine levels need to be monitored closely.

SURGICAL MANAGEMENT

EMERGENCY PERCUTANEOUS CORONARY INTERVENTIONS (PCIs)

The patient in whom an acute MI is suspected may be referred for an immediate PCI. PCI is used to open the occluded coronary artery in an acute MI and promote reperfusion to the area that has been deprived of oxygen. PCI treats the underlying atherosclerotic lesion

These include PTCA, intracoronary stent implantation, atherectomy, brachytherapy, and transmyocardial laser revascularization. All of these procedures are classified as percutaneous coronary interventions (PCIs).

Percutaneous Transluminal Coronary Angioplasty (PTCA)

The purpose of PTCA is to improve blood flow within a coronary artery by “cracking” the atheroma. This invasive interventional procedure is carried out in the cardiac catheterization laboratory.

  • The coronary arteries are examined by angiography and the location, extent, and calcification of the atheroma are verified.
  • Hollow catheters, called sheaths, are inserted, usually in the femoral vein or artery. After the presence of atheroma is verified, a balloon-tipped dilation catheter is passed through the sheath along a guide catheter and positioned over the lesion seen with fluoroscopy.
  • When the catheter is properly positioned, the balloon is inflated with a radiopaque contrast a blood vessel. The balloon is inflated for severalseconds and then deflated. The pressure “cracks” and possiblycompresses the atheroma .

COMPLICATIONS OF PTCA

  • Dissection
  • Perforation
  • Vasospasm of the coronary artery
  • Acute MI
  • Acute dysrhythmias
  • Cardiac arrest

PREPROCEDURE CARE

  • Instruct the patient to fast, usually for 8 to 12 hours before the procedure.
  • Prepare the patient for the expected duration of the procedure.
  • Reassure the patient that mild sedatives or moderate sedation will be given intravenously.
  • Prepare the patient to experience certain sensations during. The patient may be asked to cough and to breathe deeply, especially after the injection of contrast agent.
  • Encourage the patient to express fears and anxieties. Provide teaching and reassurance to reduce apprehension.

POSTPROCEDURE CARE

  1. Observe site for bleeding or hematoma formation, and assess the peripheral pulses in the affected extremity every 15 minutes for 1 hour, and then every 1 to 2 hours until the pulses are stable.
  2. Hemostasis is usually achieved and sheaths are pulled immediately at the end of the procedure by using a vascular closure device (eg, Angio-Seal) or a device that sutures the vessels (Prostar, Perclose). Hemostasis after sheath removal may also be achieved by direct manual pressure, a mechanical compression device (eg, C-shaped clamp), or a pneumatic compression device (eg, FemStop).
  3. The patient must remain flat in bed and keep the affected leg straight until the sheaths are removed and then for a few hours after to maintain hemostasis.
  4. Evaluate temperature and color of the affected extremity and any patient      complaints of pain, numbness, or tingling sensations to determine signs of arterial insufficiency. Report changes promptly.
  5. Analgesic medication is administered as prescribed for discomfort.
  6. Instruct the patient to report chest pain and bleeding or sudden discomfort    immediately.
  1. Encourage fluids to increase urinary output and flush out the dye.
  2. Ensure safety by instructing the patient to ask for help when getting out of    bed the first time after the procedure, because orthostatic hypotension may occur and the patient may feel dizzy and lightheaded.

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