Cardiovascular Disorders

CHAPTER 3 Cardiovascular Disorders

Section One Diseases of the Cardiovascular System

Hypertension

Overview/Pathophysiology

The incidence of hypertension among adults in the United States is 10%-15%, and the disease affects 50 million persons. One half of individuals over the age of 65 are affected by hypertension.

Complications of this disease include increased incidence of transient ischemic attack/stroke, retinopathy, coronary artery disease (CAD), heart failure (HF), aortic aneurysm, and renal failure.

Assessment

History and risk factors

Family history, race (incidence is higher in African-Americans), high salt intake, renal disease, obesity, excessive alcohol intake, smoking, and some endocrine disorders (i.e., Cushing’s disease, pheochromocytoma).

Collaborative Management

The goal of treatment is a BP less than 140/90 mm Hg or less than 130/80 mm Hg if diabetes or renal disease is present. Treatment for this disease includes promotion of lifestyle modification: smoking cessation; weight loss; exercise; decreased intake of saturated fats, cholesterol, (Na⁺), and alcohol; adequate dietary K⁺.

The JNC 7 recommends initiating therapy in patients with uncomplicated stage 1 hypertension with a low-dose thiazide diuretic (such as hydrochlorothiazide, 12.5-25 mg). This drug improves outcomes, has few side effects, and is low in cost. Second-line drug therapy (needed for most patients with stage 2 hypertension) includes adding an angiotensin-converting enzyme (ACE) inhibitor, an angiotensin receptor blocker (ARB), a β-blocker, or a calcium channel blocker (CCB).

Nursing Diagnoses and Interventions

Deficient knowledge

related to need for frequent BP checks and adherence to antihypertensive therapy and lifestyle changes

Desired outcome

Patient verbalizes knowledge of the importance of frequent BP checks and adhering to antihypertensive therapy and lifestyle changes.

Patient-Family Teaching and Discharge Planning

Reinforce patient teaching described under Deficient knowledge. Also provide verbal and written information about the following:

♦ Medications, including drug names, purpose, dosage, schedule, precautions, and potential side effects. Also discuss drug/drug, food/drug, and herb/drug interactions.

♦ Hypertension is a chronic disease requiring lifetime treatment.

♦ Need for physical support from family and outside agencies.

♦ Self-evaluation of BP if indicated: Monitoring machines are available in local department stores and pharmacies. Remind patient that evaluation of BP should be done while seated, ideally at the same time each day, and recorded.

♦ Availability of community and medical support from organizations such as the American Heart Association (website):

www.americanheart.org

Coronary Artery Disease

Overview/Pathophysiology

Coronary artery disease (CAD), the leading cause of death in the United States, affects almost 17 million Americans. More than 12 million have a history of angina or myocardial infarction (MI) or both. The coronary arteries supply the myocardial muscle with O₂ and the nutrients necessary for optimal function. In CAD, the arteries are narrowed or obstructed, potentially resulting in cardiac muscle death. Atherosclerotic lesions, arterial spasm, platelet aggregation, and thrombus formation all may cause obstruction. The most common symptom of CAD is angina, which is the result of decreased blood flow and insufficient O₂ supply to the heart muscle.

Acute coronary syndrome (ACS) refers to an imbalance between myocardial O₂ supply and demand secondary to an acute plaque disruption or erosion. ACS is an umbrella term that includes unstable angina (USA), non–ST-elevation myocardial infarction (NSTEMI), and ST-segment elevation myocardial infarction (STEMI).

USA is defined as an increase in severity, frequency, or intensity of anginal pain or a new onset of prolonged rest angina. This definition is based largely on clinical presentation. NSTEMI is defined by clinical presentation of chest pain with an elevation in cardiac biomarkers and changes on ECG that may include T-wave inversion or ST-segment depression but no ST-segment elevation. Diagnosis of STEMI is based on elevated cardiac biomarkers plus ST-segment elevation on ECG signifying ischemia. Of the three, STEMI is the most serious and life-threatening.

Assessment

Signs and symptoms/physical findings

Chest pain, substernal pressure and burning, and pain that radiates to the jaw, shoulder, or arm are the most common symptoms of CAD. Weakness, diaphoresis, nausea, vomiting, and acute anxiety also can occur. Heart rate (HR) may be abnormally slow (bradycardia), especially in right coronary artery (RCA) infarct, or may be rapid (tachycardia). Stable or progressively worsening angina occurs when myocardial demand for O₂ is more than the supply, such as during exercise. Pain usually is described as pressure or a crushing or burning substernal pain that radiates down one or both arms. It can be felt also in the neck, cheeks, and teeth. Usually it is relieved by discontinuation of exercise or administration of nitroglycerin (NTG).

Acute syndromes may have clinical manifestations of anxiety, hypertension, tachycardia, tachypnea, and dynamic changes on ECG. Severe hypotension may occur in shock states. Temperature elevations can occur secondary to the inflammatory process. Intensity of S₁ and S₂ heart sounds may be decreased. Pulmonary congestion may occur if ventricular failure is present, and S₃ and S₄ sounds may be auscultated.

History/risk factors

Family history, increasing age, male gender, smoking, oral contraceptive use, cocaine use, long-term use of nonsteroidal antiinflammatory drugs (NSAIDs), low high-density lipoprotein (HDL) values, hypercholesterolemia, diabetes mellitus (DM), hypertension. Obesity, glucose intolerance, low serum folate levels, exposure to air pollution from traffic, and a sedentary, stressful lifestyle also contribute to increased risk. Chest pain often occurs with exertion.

Diagnostic Tests

ECG

Usually normal unless an MI has occurred or the individual is experiencing angina at the time of the test. If ECG is performed during chest pain, characteristic changes may include ST-segment elevation or depression greater than 0.05 mV in leads over the area of ischemia. The presence of a bundle branch block (BBB) also can be determined on ECG, as well as dysrhythmias. Serial ECGs are done in patients with ACS to identify area and extent of the infarct.

Cardiac biomarkers

Creatine kinase (CK), MB fraction of creatine kinase (CK-MB), and troponin are proteins released in response to ischemia or MI. Troponin may not be elevated on initial presentation. Serial enzymes q8h × 3 are recommended for accurate assessment of myocardial damage.

C-reactive protein

If elevated from normal range of 0.03-1.1 mg/dL, signals that coronary artery plaques are inflammatory and patient is at higher likelihood of an acute coronary event.

Echocardiogram

Assesses ventricular function, chamber size, valvular function, ejection fraction, wall motion, and hemodynamic measurements. Heart muscle damage may alter ventricular function, wall motion, and hemodynamic pressures.

Chest x-ray examination

Usually normal unless HF is present.

Total lipid panel

Obtained at some point during patient’s evaluation and treatment to assess for hyperlipidemia, a risk factor in CAD. Low levels of HDL (value less than 40 mg/dL) and high levels of low-density lipoprotein (LDL) (value greater than 100 mg/dL) are linked to atherosclerotic heart disease.

Stress tests

Over the past 2 decades, stress testing with concurrent imaging of the heart has become a standard means of evaluation. Stress tests typically are prescribed to assess coronary artery flow.

Exercise treadmill test

Determines amount of exercise-induced ischemia, hemodynamic response, and changes on ECG with exercise. Significant findings include 1 mm or more ST-segment depression or elevation, dysrhythmias, or a sudden decrease in BP.

Stress echocardiogram

Typically performed using either a treadmill or a bicycle. Echocardiograms are obtained before and immediately after exercise. A stress-induced imbalance in the myocardial supply/demand ratio will produce myocardial ischemia and regional wall motion abnormality. Stress echocardiography is particularly useful for identifying CAD in patients with multivessel disease.

Pharmacologic stress test

Pharmacologic agent used to stress heart for patients unable to exercise. Adenosine, dipyridamole, and the newly approved regadenoson are commonly used pharmacologic stress agents. Dobutamine is a second-line agent used when vasodilation stress in contraindicated.

Nuclear stress test

Radionuclide, such as thallium-201 or technetium-99m sestamibi, is injected and used to track myocardial perfusion and identify pattern of ischemia when the heart is stressed either by exercise or pharmacologic agent. Myocardial perfusion imaging detects CAD by documenting normal blood flow and normal tracer uptake in unobstructed coronary arteries and diminished flow and diminished tracer uptake in stenotic coronary arteries. A perfusion abnormality also is seen in an area of MI.

Cardiac nuclear imaging

Single photon emission computed tomography (SPECT)

Myocardial imaging technique that provides three-dimensional views of cardiac processes and cellular level metabolism by viewing the heart from several different angles and using tomography methods to reconstruct the image. SPECT enables clearer resolution of myocardial ischemia and better quantification of cardiac damage.

Resting radionuclide angiography (RNA)

Evaluates left ventricular ejection fraction (LVEF) and right ventricular ejection fraction (RVEF), LV volume, and regional wall motion. The first pass technique is a fast acquisition of myocardial images. Gated pool ejection or multiple-gated acquisition (MUGA) scan permits calculation of the amount of blood ejected with ventricular contraction and is used for risk stratification of patients after MI or with CAD.

Computed tomography (CT) scan

May be helpful in differentiating acute myocardial infarction (AMI) from aortic dissection in patients with severe, tearing back pain and associated dyspnea and/or syncope.

Ambulatory monitoring

A 24-hr monitoring by ECG (using a Holter monitor) can show activity-induced ST-segment changes or ischemia-induced dysrhythmias.

Coronary arteriography via cardiac catheterization

Gold standard of diagnostic testing for CAD. Arterial lesions (plaque) are located, and the amount of occlusion is determined. During this test, feasibility for coronary artery bypass grafting (CABG) or angioplasty is determined. For details, see “Cardiac Surgery,” p. 139, and “Collaborative Management” (next major subsection).

Intravascular ultrasound (IVUS)

Assesses degree of atherosclerosis during coronary angiogram. A flexible catheter with a miniature transducer at the tip is threaded from an arteriotomy (commonly femoral) retrograde to the coronary arteries to provide information on the interior of the coronary arteries. Ultrasound is used to create a cross-sectional image of the three layers of the arterial wall and its lumen.

Collaborative Management

Emergency department (ED) management

Aspirin is administered to all patients unless contraindicated. Time is of the essence in determining a treatment plan. All patients presenting to the ED with STEMI are considered high-priority triage cases. Primary angioplasty is widely viewed as therapy of choice for reperfusion in AMI. However, not all acute-care hospitals in the United States have availability for percutaneous coronary intervention (PCI). Because time is so critical in patients presenting with STEMI, a decision must be made by the ED physician to proceed with either fibrinolytic therapy or primary PCI within 10 min of presentation. The goal for door-to-needle time is within 30 min and door-to-balloon time within 90 min. Initiating thrombolysis within 70 min of symptom onset is key to reducing mortality and morbidity. If catheterization laboratory facilities for primary intervention are not available within this time frame, fibrinolytics are administered until transport can be arranged.

Relief of acute pain

Achieved with sublingual NTG, IV NTG, and/or morphine sulfate. IV NTG drip should be increased in increments of 10 mcg if pain persists, and SBP should be maintained at 90 mm Hg or higher until pain is relieved. IV morphine sulfate is added in small increments (2 mg).

O₂ therapy

Usually 2-4 L/min is given by nasal cannula. Hypoxia is common and adds stress to the compromised myocardium.

β-Blockers

Usually administered by IV route as initial treatment to slow the HR and decrease cardiac workload.

Treatment and prevention of dysrhythmias

Antidysrhythmic agents (e.g., lidocaine) for premature ventricular beats and atropine for bradydysrhythmias.

Antithrombins

Onset of unstable CAD is typically caused by rupture or erosion of an atherosclerotic plaque with development of a thrombus. Antithrombin drugs such as unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) are administered to halt further thrombus formation. UFH has been shown to have a low and variable bioavailability, which necessitates frequent hematologic evaluations. Patients receiving LMWHs do not require frequent blood testing.

Fibrinolytics (used with STEMI)

In AMI, the goal of therapy is to restore patency and blood flow. One of the first-generation fibrinolytic drugs was streptokinase. Newer fibrinolytics have fewer side effects and are used more commonly. Alteplase, a second-generation fibrinolytic, is a weight-adjusted drug that must be given as a continuous infusion. Reteplase (Retavase, Rapilysin), a recombinant plasminogen activator (rPA) and one of the third-generation fibrinolytics, does not require continuous infusion and is a non–weight-based drug. Another third-generation fibrinolytic, tenecteplase (TNK), is administered as a single bolus and, like alteplase, is a weight-based drug. Intracranial hemorrhage is a risk with fibrinolytic drugs and should be monitored for.

Heparin therapy

LMWH or standard UFH is used along with or following fibrinolytic therapy to inhibit further clotting and prevent recurring coronary artery occlusion. Recombinant hirudin is a direct-action antithrombin agent for patients receiving fibrinolytic agents and is available for those who have heparin sensitivity.

Management of fluid balance

Oral or IV fluids for dehydration; diuretics for fluid overload and/or treatment of ventricular failure.

Transfer to coronary care unit (CCU)

May be necessary if patient is hemodynamically unstable.

PCI

A procedure that improves coronary blood flow by using a balloon inflation catheter to rupture plaque and dilate the artery. It is performed in the cardiac catheterization laboratory and uses local anesthesia and mild sedation, to enable patient to be awake and interact with the health care team. PCI is a common alternative to bypass surgery for individuals with discrete lesions. Balloon angioplasty traditionally is followed by stent placement. Following the procedure, patients routinely are placed on antiplatelet agents (i.e., acetylsalicylic acid [aspirin, ASA] and clopidogrel [Plavix]) to reduce risk of in-stent restenosis after PCI. Additionally, drug-eluting stents are now available that further reduce risk of restenosis. An antirestenotic drug contained within the polymer of these stents is released over time to modify the healing response that would result in restenosis. Complications of PCI include bleeding, vascular injury, infection, MI, stroke, contrast-induced nephropathy, allergic reaction to medications or contrast, and death.

Long-Term Management of ACS

Management of risk factors

Include eliminating tobacco, reducing BP, reducing serum lipid levels, controlling weight and stress, and initiating an exercise program.

O₂ therapy by nasal cannula

May be used during periods of angina.

Diet

Low in cholesterol (TABLE 3-1), saturated fat (TABLE 3-2), Na⁺ (see Box 4-1, p. 165), calories, and triglycerides, as appropriate.

TABLE 3-1 GUIDELINES FOR A DIETLOW IN CHOLESTEROL

FOODS TO AVOID	FOODS TO CHOOSE
Egg yolks (no more than 3/wk); foods made with many egg yolks (e.g., sponge cakes)	Egg whites, cholesterol-free egg substitutes
Fatty cuts of meat, fat on meats, luncheon meats or cold cuts, sausage, frankfurters	Lean, well-trimmed meats (minimize servings of beef, lamb, pork); dried peas and beans as meat substitutes
Shellfish (e.g., lobster, shrimp, crab); skin on chicken and turkey	Lean fish; skinless chicken and turkey
Whole milk, cream; whole milk cheese	Nonfat (skim) or low-fat (1% or 2%) milk; partially skim milk cheeses
Ice cream	Ice milk, sherbet, sorbet
Coconut and palm oils and products made with them (e.g., cream substitutes)	Polyunsaturated oils for cooking and food preparation: corn, safflower, cottonseed, sesame, sunflower
Commercially prepared foods with hydrogenated shortening (saturated fat)	Foods prepared from scratch with the suggested oils
Butter, lard, hydrogenated shortening	Margarines that list one of the polyunsaturated oils as their first ingredient
Fried meats and vegetables	Meats (in acceptable quantity) and vegetables prepared by broiling, steaming, or baking
Salad dressings containing cream, cheeses, or mayonnaise; sauces and gravies; seasonings containing large amounts of sugar and saturated fats	Spices, herbs, lemon juice, wine, flavored wine vinegars

TABLE 3-2 GUIDELINES FOR A DIET LOW IN SATURATED FAT

FOODS TO AVOID	FOODS TO CHOOSE
Red meat, especially when highly marbled; salami, sausage, bacon	Lean cuts of meat, fresh fish, poultry with skin removed before cooking, grilled meats
Whole milk, whipping cream	Nonfat (skim) or low-fat (1% or 2%) milk
Tropical oils (coconut, palm oils; cocoa butter)	Monounsaturated cooking oils (e.g., olive or canola oil)
Butter	Margarine (safflower oil listed as the first ingredient)
Salad dressing	Vinegar, lemon juice
Peanuts, peanut butter, hot dogs, potato chips	Unbuttered popcorn
Candy	Fresh fruits, vegetables
Ice cream	Nonfat yogurt, sherbet
Sweet rolls, donuts	Whole grain breads, cereals

Nursing Diagnoses and Interventions

Acute pain (angina)

related to decreased O₂ supply to the myocardium

Desired outcome

Within 30 min of onset of pain, patient’s subjective perception of angina decreases, as documented by pain scale. Objective indicators, such as grimacing and diaphoresis, are absent.

Nursing Interventions

♦ Assess location, character, and severity of pain. Record severity on a subjective 0 (no pain) to 10 (worst pain) scale. Also record number of NTG tablets needed to relieve each episode, the factor or event that precipitated pain, and alleviating factors. Document angina relief obtained, using pain scale.

♦ Keep sublingual NTG within reach of patient, and explain that it is to be taken as soon as angina begins and the nurse notified.

♦ Obtain ECG as prescribed to assess for ischemia

♦ Stay with patient and provide reassurance during periods of angina.

♦ Monitor HR and BP during episodes of chest pain. Be alert to and report irregularities in HR and changes in SBP greater than 20 mm Hg from baseline.

♦ Monitor for presence of headache and hypotension after administering NTG. Keep patient recumbent during angina and NTG administration.

♦ Administer O₂ as prescribed to increase O₂ supply to the myocardium. Deliver O₂ with humidity to help prevent its drying effects on oral and nasal mucosa.

♦ Emphasize to patient importance of immediately reporting angina to health care team.

♦ Instruct patient to avoid activities and factors known to cause stress and that may precipitate angina.

♦ Discuss value of relaxation techniques, including tapes, soothing music, biofeedback, meditation, or yoga. See Health-seeking behaviors, later.

♦ Administer β-blockers as prescribed to decrease cardiac workload and O₂ demand.

♦ Administer long-acting and/or topical nitrates to decrease O₂ demand and likelihood of angina.

Activity intolerance

related to generalized weakness and imbalance between O₂ supply and demand secondary to tissue ischemia (MI)

Desired outcomes

During activity, patient rates perceived exertion at 3 or less on a 0-10 scale and exhibits cardiac tolerance to activity, as evidenced by respiratory rate (RR) 20 breaths/min or less, HR 120 beats per minute (bpm) or less (or within 20 bpm of resting HR), SBP within 20 mm Hg of patient’s resting SBP, and absence of chest pain and new dysrhythmias.

Nursing Interventions

♦ Observe for and report increasing frequency of angina, angina that occurs at rest, angina that is unrelieved by NTG, or decreased exercise tolerance without angina. See BOX 3-1 for classifications of angina.

♦ Assess patient’s response to activity. Be alert to chest pain, increase in HR (greater than 20 bpm), change in SBP (20 mm Hg over or under resting BP), excessive fatigue, and shortness of breath. Ask patient to rate perceived exertion (see p. 90 for details).

♦ Assist patient with recognizing and limiting activities that increase O₂ demands, such as exercise and anxiety.

♦ Administer O₂ as prescribed for angina episodes. Deliver O₂ with humidity to help prevent its drying effects on oral and nasal mucosa.

• Have patient perform ROM exercises, depending on tolerance and prescribed activity limitations. Because cardiac intolerance to activity can be further aggravated by prolonged bed rest, consult health care provider about in-bed exercises and activities that can be performed by patient as the condition improves.

♦ For further interventions, see “Prolonged Bed Rest,” Risk for activity intolerance, p. 23, and Risk for disuse syndrome, p. 25.

Deficient knowledge

related to catheterization procedure and postcatheterization regimen

Desired outcome

Before the procedure, patient verbalizes knowledge about cardiac catheterization and the postcatheterization plan of care.

Nursing Interventions

♦ Assess patient’s facility with language; engage an interpreter or provide language-appropriate written materials if indicated.

♦ Assess patient’s knowledge about catheterization procedure. As appropriate, reinforce health care provider’s explanation, and answer any questions or concerns. If possible, arrange for an orientation visit to catheterization laboratory before the procedure.

♦ Before cardiac catheterization, have patient practice techniques (e.g., Valsalva maneuver, coughing, deep breathing) that will be used during procedure.

♦ Explain that after the procedure, bed rest will be required and VS, circulation, and insertion site will be checked at frequent intervals to ensure integrity. In addition, explain that flexion at insertion site (arm or groin) is contraindicated to prevent bleeding.

♦ Stress importance of promptly reporting signs and symptoms of concern, including groin, leg, or back pain; dizziness; chest pain; or shortness of breath. Any of these symptoms may indicate hemorrhage or embolization of the stent.

Ineffective cardiopulmonary, peripheral, and cerebral tissue perfusion

related to interrupted arterial flow secondary to catheterization procedure

Desired outcomes

Within 1 hr after the procedure, patient has adequate perfusion, as evidenced by HR regular and within 20 bpm of baseline HR; apical/radial pulse equality; BP within 20 mm Hg of baseline BP; peripheral pulse amplitude greater than 2+ on a 0-4+ scale; warmth and normal color in the extremities; no significant change in mental status; and orientation to person, place, and time.

Nursing Interventions

♦ Monitor BP q15min until stable on three successive checks, q2h for the next 12 hr, and q4h for 24 hr unless otherwise indicated. If SBP drops 20 mm Hg or more below previous recordings, lower head of bed (HOB) and notify health care provider. If insertion site was the antecubital space, measure BP in unaffected arm.

♦ Be alert to and report indicators of decreased perfusion, including cool extremities, decreased amplitude of peripheral pulses, cyanosis, changes in mental status, decreased level of consciousness (LOC), and shortness of breath.

♦ Monitor HR, and notify health care provider if dysrhythmias occur. If patient is not on a cardiac monitor, auscultate apical and radial pulses with every BP check and report irregularities or apical/radial discrepancies.

♦ If the femoral artery was the insertion site, maintain HOB at no greater than a 30-degree elevation to prevent acute hip joint flexion, which could compromise arterial flow.

Risk for deficient fluid volume

related to risk factors from hemorrhage or hematoma formation caused by arterial puncture and/or osmotic diuresis from the dye

Desired outcomes

Patient remains normovolemic, as evidenced by HR 100 bpm or less; BP 90/60 mm Hg or greater (or within 20 mm Hg of baseline range); no significant change in mental status; and orientation to person, place, and time. The dressing is dry, and there is no swelling at the puncture site.

Nursing Interventions

♦ Be alert to indicators of shock or hemorrhage, such as a decrease in BP, increase in HR, and decreasing LOC.

♦ Inspect dressing on groin or antecubital space for presence of frank bleeding, and check for hematoma formation (fluctuating swelling).

♦ Monitor peripheral perfusion, and be alert to decreased amplitude or absence of distal pulses, delayed capillary refill, coolness of the extremities, and pallor, any of which can signal embolization or hemorrhagic shock.

♦ Caution patient about flexing elbow or hip more than 30 degrees for 6-8 hr, or as prescribed, to minimize risk of bleeding and/or compromised circulation.

♦ If bleeding occurs, maintain pressure at insertion site as prescribed, usually 1 inch proximal to puncture site or introducer insertion site. Typically this is done with a pressure dressing or a

to 5-1b sandbag.

Ineffective peripheral (involved limb) tissue perfusion (or risk of same)

related to interrupted arterial flow secondary to embolization

Desired outcome

Patient has adequate perfusion in the involved limb, as evidenced by peripheral pulse amplitude greater than 2+ on a 0-4+ scale; normal color, sensation, and temperature; and brisk capillary refill (refill time less than 2 sec).

Ineffective renal tissue perfusion

(or risk for same) related to interrupted blood flow secondary to decreased cardiac output or reaction to contrast dye

Only gold members can continue reading. Log In or Register to continue

Related

Stay updated, free articles. Join our Telegram channel

Tags: Manual of Medical-Surgical Nursing Care Nursing Interventions an

Sep 1, 2016 | Posted by admin in NURSING | Comments Off

Full access? Get Clinical Tree

Get Clinical Tree app for offline access

Get Clinical Tree app for offline access