Cardiac/Vascular Nurse Exam Secrets Study Guide (2 page)

Borg scale

Frequently used in outpatient and community exercise programs, the Borg scale is a method to evaluate patient exertion based on breath quality and perceived exhaustion. The subjective data—perceived increases in heart rate, respirations, sweating and muscle endurance—are rated on an ascending scale of 6–20. A mild physical effort would produce a lower number; extreme exertion would correlate with a higher number. This scale number also provides a fairly accurate estimate of the patient’s actual pulse rate when multiplied by 10 (i.e., a rating of 9 [mild exertion] would correlate to a generalize pulse rate of 90). This method can be taught to the patient in order to assess his/her exertion level outside of a monitored, therapeutic environment.

Qualitative and quantitative methods of data collection

Qualitative: Seeks to identify generalities and answer initial questions regarding a situation or incident. Its focus is on exploring and observing to gain information. Answers and information are expressed in word and theory. Data gathered and conclusions made can be more subjective than quantitative data. It is generally used as a first step or in conjunction with more strictly defined quantitative studies.

Quantitative: Answers specific questions, tests theories, establishes cause and effect relationships, gauges impact and outcome of various conditions and can be translated into mathematical answers. Quantitative studies are generally easier to duplicate for credibility.

Age-related cardiovascular changes an older patient may experience

The risk for blockage by constriction of the vessels or blood clots increases with age, as does a tendency toward pooling blood in the legs and feet.

Cardiac output is reduced. Cardiac tissue and vessels can become hardened or brittle or become narrowed from plaque and inflammation buildup, all of which reduce cardiac efficiency and restrict blood flow.

Exercise endurance and oxygen perfusion is reduced. Many of these factors can be mitigated by maintaining an active lifestyle, with a focus on endurance training, as the patient ages.

Criteria, according to the AHA, for placing a patient on continuous cardiac (telemetry) monitoring

• Class I: These patients are under the highest risk for immediate, life-threatening cardiac events. They require continuous monitoring under the supervision of a practitioner highly skilled in both ECG interpretation and defibrillation. This level of care suggests intensive care treatment.
  
• Class II: This is a lower risk classification, suggested for patients on cardiac medications, minor surgical interventions such as angioplasty or pacemaker lead placement. These patients are normally found on a cardiac step-down or intermediate cardiac care unit.
  
• Class III: Patients carrying the lowest risk for cardiac events but requiring a short interval of increased monitoring, such as surgical and labor patients.
  

Uses of chest x-ray, computed tomography (CT) scan and magnetic resonance imaging (MRI)

Chest x-ray: Used for initial evaluation, x-ray provides a cursory view of the chest organs including size and position of the heart and health of the lungs.

CT scan: Without the use of contrast dye, this is still considered a noninvasive procedure utilizing concentrated x-rays. CT scans are useful for expanding the available view of an organ to a more 3-dimensional picture.

MRI: Uses a magnetic field to create a computerized 3-dimensional image without the use of harmful radiation; however, it is consequently the most expensive of the three procedures. MRI provides the most accurate and detailed information regarding the status of the soft tissue organs.

Expected pattern of creatine kinase (CK) results in the hours and days following a myocardial infarction (MI)

CK and CK-MB levels are evaluated every 6–8 hours in a suspected myocardial injury. Total CK and CK-MB (specific to cardiac cells) initially rise within the first 4–6 hours of an MI. A normal range would be 30 IU/L to 180 IU/L for CK and CK-MB totaling 0–5% of the CK level.

Assuming no further damage is sustained, peak levels (in excess of 6 times the normal range) are reached 12–24 hours after the injury.

CK levels will return to normal within 3–4 days of the event.

Small spikes in CK level might also occur following invasive cardiac procedures.

Typical changes that might be seen on an electrocardiogram (ECG) indicating the presence of heart disease

In a normal ECG, P waves are no taller than 0.25 mV and no wider than 0.11 seconds. A normal PR interval is 0.12–0.20 seconds. A normal QRS is 0.04–0.10 seconds. T waves gently curve upright and are no taller than 5 mm (10 mm in chest leads). U waves, when visible are also upright in the presence of myocardial injury, T waves turn upside down or become markedly tall. Higher T waves may be thinner than normal, or longer and followed by an inverted U wave.

ST segment drops below the baseline or measures wider than 0.12 seconds. The ST segment might not have a return to the baseline between S and T.

Q waves may measure greater than 0.03 seconds.

Aneurysms

An aneurysm is defined as a localized, blood-filled dilation of a blood vessel (artery or vein) caused by cardiac disease or weakening of the blood vessel wall. Aneurysms most commonly occur within the intracranial vessels, but are also found along the thoracic aorta, abdominal aorta, and in vessels of the extremities.

Aneurysms typically occur in elderly patients, but can present in patients of any age group. However, aneurysms are uncommon in individuals under 20 years of age. The risk of aneurysm increases with age and is most likely to occur in individuals between the ages of 50 and 80.

Aneurysms are more common in Caucasian patients than individuals of other ethnicities. Typically, men develop aneurysms more often than women do. However, women with aneurysms have a risk of rupture significantly higher than that of men.

Approximately 15,000 individuals in the United States die each year from ruptured aneurysms. Ruptured aneurysms are the 10th leading cause of death in men over age 50 in the United States.

Types of aneurysms

A peripheral aneurysm is more likely to affect individuals ages 60 to 80. Cerebral aneurysms are more likely to occur in people ages 35 to 60.

Approximately 0.2% to 3% of individuals in the United States with a brain aneurysm suffer from hemorrhage per year, with 10% to 15% of these individuals dying prior to obtaining care and over 50% dying within 1 month post rupture. Approximately half of patients surviving a rupture suffer from permanent neurological damage.

Abdominal aortic aneurysms are 4 times more common in men than in women and are most prevalent in Caucasians ages 40 to 70. Less than 50% of individuals with a ruptured abdominal aortic aneurysm survive.

Symptoms associated with aneurysms

Typically, aneurysms are asymptomatic until they grow large enough to cause symptoms. Associated symptoms vary by location of the aneurysm. Aneurysms located closer to the surface of body may present with swelling and pain; however, most aneurysms within the body are asymptomatic.

Aneurysms in the brain can present with symptoms of localized severe headache, intense pressure, nausea and vomiting, neck pain, blurred or double vision, pain in or around the eye, dilated pupils, sensitivity to light, and loss of sensation.

Aneurysms in the abdomen may present with a deep dull penetrating pain in the lower back or abdomen that lasts for days to hours.

Signs and symptoms of a peripheral aneurysm may include leg or arm cramping, coldness, and numbness or tingling in the feet due to blocked blood flow to the peripheral arteries.

Risk factors

Risk factors that can potentially lead to aneurysm formation: atherosclerosis, smoking, obesity, hypertension, head or body trauma, alcohol consumption, use of oral contraceptives, Marfan syndrome, tuberculosis, untreated syphilis, vasculitis, Caucasian ethnicity, male gender, and family history of aneurysms or heart diseases.

Smoking is a strong risk factor for the development of an aneurysm, with risk increasing according to the number of pack years. Increased blood pressure and atherosclerosis are also risk factors for aneurysms due to increased pressure within the blood vessels and damage to blood vessel walls.

Genetic disorders, including Marfan syndrome, can lead to aneurysm formation, as the disease affects connective tissue throughout the body, including the tissues of the blood vessels.

Another risk factor is a family history of aneurysms. Individuals with a family history of aneurysms typically develop aneurysms at an earlier age and should be monitored by a specialist.

Aneurysm diagnosis

Physical examination sometimes suggests aneurysms. For example, a pulsating abdominal mass suggests an aneurysm of the abdominal aorta. Medical imaging is used for definitive diagnosis including chest x-ray, ultrasound, magnetic resonance imaging (MRI), angiography, and computer tomography (CT) scan. Aneurysms are often incidentally found while imaging a patient for other reasons.

Patients at high risk for aneurysms should be followed regularly by a cardiothoracic, vascular, or neurological surgeon. Current guideline recommendations suggest that men who are 65 to 75 years old and are ex-smokers should be checked for aneurysms routinely. Men aged 60 and older with a family history of aneurysms should also consider routine screening.

Aneurysm complications

Aneurysm rupture can lead to complications such as sudden death, stroke, and brain damage. Signs and symptoms of aneurysm rupture include hypotension, rapid heartbeat, lightheadedness, fainting, nausea, vomiting, sweating, shortness of breath, chest pain, lower back/abdominal pain, and dizziness. The risk of death is high with aneurysm rupture, except for rupture in the extremities. Also, the risk of rupture increases as the blood vessel dilation increases.

Another complication of aneurysms is the risk of blood clots. The occlusion of blood flow can lead to complications such as brain damage, lack of peripheral blood flow to end organ systems or extremities, and sudden death. Blood clots can also dislodge from the site of origin and cause the above complications.

Atherosclerosis

Atherosclerosis is a disease caused by formation of plaque in the walls of arteries. Plaque formation is caused by a chronic inflammatory response and endothelial dysfunction where lipids, cholesterol, calcium, and other substances build up in the arteries. There is an imbalance between deposition of plaque and removal by low-density lipoproteins in smooth muscle cells. Two types of plaques can form in the arteries including stable plaques and unstable plaques. Stable plaques consist of a thick fibrous cap of smooth muscle cells that upon stimulation can lead to reduced blood flow to heart, lung, and other organ systems. Unstable plaques consist of a thin fibrous cap of smooth muscle cells that can rupture leading to a heart attack and/or stroke.

The disease can affect arteries in the heart, brain, lungs, and extremities. Therefore, based on the origin of the condition, atherosclerosis can be referred to as coronary heart disease, when present in coronary arteries, carotid artery disease when present in the carotid artery, and peripheral arterial disease when present in the arteries supplying the extremities.

In the United States, more than 11 million Americans have atherosclerosis. Atherosclerosis is the leading cause of coronary heart disease and stroke, with the disease responsible for more than half of the annual deaths. Over 1 million individuals in the United States annually are diagnosed with coronary artery disease and nearly 700,000 individuals suffer a stroke.

Atherosclerosis is a condition that develops over time, presenting symptoms in patients between the ages of 40 and 70 due to hardening of plaques, vascular remodeling, blood flow abnormalities, and diminished oxygen flow to end organ systems. Patients between the ages of 50 and 60 typically present with advanced complications of the condition as well as organ system dysfunction.

Individuals with an increased risk of atherosclerosis include men and patients with a family history of cardiovascular disease. The lower prevalence of atherosclerosis in women may be due to the protective effects of estrogen and progesterone. However, this hormonal protective effect has been shown to decrease after menopause, unless the individual is undergoing hormone replacement therapy.

Risk factors and complications

Factors that can increase an individual’s risk for atherosclerosis include elevated low-density lipoprotein (LDL) cholesterol, decreased high-density lipoprotein (HDL) cholesterol, elevated triglyceride levels, menopause, lack of physical activity, obesity, infection of the vascular smooth muscle cells, high blood pressure, history of smoking, and diabetes.

Smoking not only predisposes individuals to atherosclerosis, but it increases the progression of the disease. The progression of atherosclerosis itself also further increases the extent and degree of the condition, as further accumulation of lipids, cholesterol, and other substances stimulates the endothelium to produce other substances that cause increased plaque buildup.

Atherosclerosis leads to altered vascular function including coronary heart disease, myocardial ischemia and myocardial infarction, cerebrovascular insufficiency, stroke, peripheral vascular disease, limb ischemia, renal disease, aortic aneurysm, and vasculitis. The final mechanism of the above complications usually occurs via plaque rupture or severe vessel narrowing and blood clotting.