Ch 35 Assessment of the Cardiovascular System
Terms in this set (126)
- It is responsible for supplying oxygen to body organs and other tissues (perfusion)
- The heart muscle, called the myocardium, must receive sufficient oxygen to pump blood to other parts of the body
- Oxygen in the blood is needed for cells to live and function properly.
- When diseases or other problems of the CV systems occur, oxygenation and perfusion decrease, often resulting in life-threatening events or a risk for these events.
- In almost every year since 1900, cardiovascular disease (CVD) has been the number-one cause of death in the United States
- The disease kills more people than the next four causes of death combined, including cancer, chronic lower respiratory diseases, accidents, and diabetes.
- Of particular concern is that CVD is the leading cause of death for women
- Is a fist-sized, muscular organ located in the mediastinum between the lungs
- During strenuous physical activity, it can double the amount of blood pumped to meet the body's increased oxygenation needs.
- The heart is protected by a covering called the pericardium.
- A muscular wall (septum) separates the heart into two halves: right and left. Each half has an atrium and a ventricle
Each beat of the heart pumps
About 60 mL of blood, or 5 L/min
- Receives deoxygenated venous blood, which is returned from the body through the superior and inferior venae cavae
- Is a muscular pump located behind the sternum. It generates enough pressure to close the tricuspid valve, open the pulmonic valve, and propel blood into the pulmonary artery and the lungs
- When the left ventricle is almost full, the left atrium (LA) contracts, pumping the remaining blood volume into the left ventricle
- With systolic contraction, the left ventricle (LV) generates enough pressure to close the mitral valve and open the aortic valve. Blood is propelled into the aorta and into the systemic arterial circulation
- Separate the atria from the ventricles
- Tricuspid valve separates the RA from the RV
- Mitral (bicuspid) valve separates the LA from the LV
- During ventricular diastole, these valves act as funnels and help move the flow of blood from the atria to the ventricles. During systole, the valves close to prevent the backflow (regurgitation) of blood into the atria
- Prevent blood from flowing back into the ventricles during diastole
- Pulmonic valve separates the right ventricle from the pulmonary artery
- Aortic valve separates the left ventricle from the aorta
- The heart muscle receives blood to meet its metabolic needs through the coronary arterial system. The coronary arteries originate from an area on the aorta just beyond the aortic valve. All of the coronary arteries feeding the left heart originate from the left main coronary artery. The right coronary artery (RCA) branches from the aorta to perfuse the right heart and inferior wall of the left heart
Coronary artery blood flow to the myocardium
- Occurs primarily during diastole, when coronary vascular resistance is minimized. To maintain adequate blood flow through the coronary arteries,
mean arterial pressure (MAP) must be at least 60 mm Hg. A MAP of between 60 and 70 mm Hg is necessary to maintain perfusion of major body organs, such as the kidneys and brain
Left Main Artery
- Divides into two branches:
1. the left anterior descending (LAD) branch
2. the left circumflex (LCX) branch.
The LAD branch
- Descends toward the anterior wall and the apex of the left ventricle. It supplies blood to portions of the left ventricle, ventricular septum, chordae tendineae, papillary muscle, and, to a lesser extent, the right ventricle
The LCX branch
- Descends toward the lateral wall of the left ventricle and apex. It supplies blood to the left atrium, the lateral and posterior surfaces of the left ventricle, and sometimes portions of the interventricular septum
Right Coronary Artery
- Originates from the right sinus of Valsalva, encircles the heart, and descends toward the apex of the right ventricle. The RCA supplies the RA, RV, and inferior portion of the LV. In about half of people, the RCA supplies the SA node, and in almost everyone, it supplies the AV node.
- Normally about two thirds of the cardiac cycle, consists of relaxation and
of the atria and ventricles.
- Consists of the
and emptying of the atria and ventricles
Cardiac Muscle Relaxation
- when calcium ions are pumped back into the sarcoplasmic reticulum, causing a decrease in the number of calcium ions around the myofibrils. This reduced number of ions causes the protein filaments to disengage, the sarcomere to lengthen, and the muscle to relax
Cardiac Output (CO)
- The amount of blood pumped from the left ventricle each minute. CO depends on the relationship between heart rate (HR) and stroke volume (SV)
- Cardiac output = Heart rate × Stroke volume
- 4 to 7 L/min. Because CO requirements vary according to body size, the cardiac index is calculated to adjust for differences in body size
- Can be determined by dividing the CO by the body surface area. The normal range is 2.7 to 3.2 L/min/m2 of body surface area.
- Less blood pumped by heart = low CI
Heart Rate (HR)
- The number of times the ventricles contract each minute.
- The normal resting HR for an adult is between 60 and 100 beats/min
- Increases in rate increase myocardial oxygen demand
- Controlled by the ANS
- The parasympathetic (vagus nerve) system slows the HR, whereas sympathetic stimulation increases the heart rate
Stroke volume (SV)
- Is the amount of blood ejected by the left ventricle during each contraction. Several variables influence SV and, ultimately, CO. These variables include HR, preload, afterload, and contractility.
- The degree of myocardial fiber stretch at the end of diastole and just before contraction
- The stretch imposed on the muscle fibers results from the volume contained within the ventricle at the end of diastole
Is determined by the amount of blood returning to the heart from both the venous system (right heart) and the pulmonary system (left heart) (left ventricular end-diastolic [LVED] volume).
- Is the pressure or resistance that the ventricles must overcome to eject blood through the semilunar valves and into the peripheral blood vessels.
- The amount of resistance is directly related to arterial blood pressure and the diameter of the blood vessels
- The peripheral component of afterload, is the pressure that the heart must overcome to open the aortic valve.
- The amount of impedance depends on aortic compliance and total systemic vascular resistance
- Is the force of cardiac contraction independent of preload
- Affects stroke volume and CO
- Contractility is increased by factors such as sympathetic stimulation, calcium release, and positive inotropic drugs. It is decreased by factors such as hypoxia and acidemia.
- The primary function is to deliver oxygen and nutrients to various tissues in the body.
- Nutrients are carried through arteries to arterioles, then branch into smaller terminal arterioles and finally join with capillaries and venules to form a capillary network.
- Within this network, nutrients are exchanged across capillary membranes by three primary processes: osmosis, filtration, and diffusion
- Delivers blood to various tissues for oxygen and nourishment
Blood Pressure (BP)
- Is the force of blood exerted against the vessel walls
- Pressure in the larger arterial blood vessels is greater (about 80 to 100 mm Hg) and decreases as blood flow reaches the capillaries (about 25 mm Hg)
- By the time blood enters the right atrium, the BP is about 0 to 5 mm Hg.
- Volume, ventricular contraction, and vascular tone are necessary to maintain blood pressure
How is BP Determined
- By the quantity of blood flow or cardiac output (CO), as well as by the resistance in the arterioles:
- Blood pressure = Cardiac output × Peripheral vascular resistance
- Any factor that increases CO or total peripheral vascular resistance increases the BP. In general, BP is maintained at a relatively constant level. Therefore an increase or decrease in total peripheral vascular resistance is associated with a decrease or an increase in CO, respectively
Three mechanisms mediate and regulate BP
• The autonomic nervous system (ANS), which excites or inhibits sympathetic nervous system activity in response to impulses from chemoreceptors and baroreceptors
• The kidneys, which sense a change in blood flow and activate the renin-angiotensin-aldosterone mechanism
• The endocrine system, which releases various hormones (e.g., catecholamine, kinins, serotonin, histamine) to stimulate the sympathetic nervous system at the tissue level
- Is the amount of pressure/force generated by the left ventricle to distribute blood into the aorta with each contraction of the heart. It is a measure of how effectively the heart pumps and is an indicator of vascular tone
- The amount of pressure/force against the arterial walls during the relaxation phase of the heart.
BP is regulated by...
- balancing the sympathetic and parasympathetic nervous systems of the autonomic nervous system.
- Changes in autonomic activity are responses to messages sent by the sensory receptors in the various tissues of the body.
- These receptors, including the baroreceptors, chemoreceptors, and stretch receptors, respond differently to the biochemical and physiologic changes of the body
- in the arch of the aorta and at the origin of the internal carotid arteries are stimulated when the arterial walls are stretched by an increased BP.
- Impulses from these baroreceptors inhibit the vasomotor center, which is located in the pons and the medulla.
Inhibition of this center results in a drop in BP
- Several 1- to 2-mm collections of tissue have been identified in the carotid arteries and along the aortic arch known as peripheral chemoreceptors.
- These receptors are sensitive primarily to hypoxemia (a decrease in the partial pressure of arterial oxygen [PaO2]).
- When stimulated, these chemoreceptors send impulses along the vagus nerves to activate a vasoconstrictor response and
The central chemoreceptors
- Are in the respiratory center of the brain are also stimulated by hypercapnia (an increase in partial pressure of arterial carbon dioxide [PaCO2]) and acidosis.
- The direct effect of carbon dioxide on the central nervous system (CNS), however, is 10 times stronger than the effect of hypoxia on the peripheral chemoreceptors
- in the vena cava and the right atrium are sensitive to pressure or volume changes.
- When a patient is hypovolemic, stretch receptors in the blood vessels sense a reduced volume or pressure and send fewer impulses to the CNS.
- This reaction stimulates the sympathetic nervous system to increase the heart rate (HR) and constrict the peripheral blood vessels.
- Also help regulate cardiovascular activity
- When renal blood flow or pressure decreases, the kidneys retain sodium and water
- BP tends to rise because of fluid retention and activation of the renin-angiotensin-aldosterone mechanism
- This mechanism results in vasoconstriction and sodium retention (and thus fluid retention).
- Vascular volume is also regulated by the release of antidiuretic hormone (vasopressin) from the posterior pituitary gland
Other factors can also influence the activity of the cardiovascular system
- Emotional behaviors (e.g., excitement, pain, anger) stimulate the sympathetic nervous system to increase blood pressure (BP) and heart rate (HR).
- Increased physical activity such as exercise also increases BP and HR during the activity.
- Body temperature can affect the metabolic needs of the tissues, thereby influencing the delivery of blood.
- In hypothermia, tissues require fewer nutrients and blood pressure falls.
- In hyperthermia, the metabolic requirement of the tissues is greater and BP and pulse rate rise.
Changes in the Cardiovascular System with Aging
- Cardiac Valves:
Calcification and mucoid degeneration occur, especially in mitral and aortic valves
- Conduction System: Pacemaker cells decrease in number. Fibrous tissue and fat in the sinoatrial node increase. Few muscle fibers remain in the atrial myocardium and bundle of His. Conduction time increases.
- Left Ventricle:
The size of the LV increases
- The aorta and other large arteries thicken and become stiffer and less distensible.
Systolic bp increases to compensate for the stiff arteries
- Baroreceptors become less sensitive
- Postmenopausal women are two to three times more likely than premenopausal women to have CAD.
- After an acute MI, women tend to have a higher mortality rate and suffer more complications when compared with men
Ask women whether they are taking oral contraceptives or an estrogen replacement. The incidence of myocardial infarction (MI) and stroke in women older than 35 years who take oral contraceptives is increased if they smoke, have diabetes, or have hypertension
If needed, the dietitian reviews the type of foods selected by the patient for the amount of sodium, sugar, cholesterol, fiber, and fat. Cultural beliefs and economic status can influence the choice of food items and therefore are seriously considered
Nursing Safety Priority Action Alert
Thoroughly evaluate the nature and characteristics of the chest pain. Because pain resulting from myocardial ischemia is life threatening and can lead to serious complications, its cause should be considered ischemic (reduced or obstructed blood flow to the myocardium) until proven otherwise. When assessing for symptoms, ask the patient if he or she has "discomfort," "heaviness," "pressure," and "indigestion."
Women's Health Considerations
Some patients, especially women, do not experience pain in the chest but instead feel discomfort or indigestion. Women often present with a "triad" of symptoms. In addition to indigestion or feeling of abdominal fullness, chronic fatigue despite adequate rest and feelings of an "inability to catch my breath" are also common in heart disease. The patient may also describe the sensation as aching, choking, strangling, tingling, squeezing, constricting, or viselike. Others with severe neuropathy may experience few or no traditional symptoms except shortness of breath, despite major ischemia
- (difficult or labored breathing) can occur as a result of both cardiac and pulmonary disease. It is experienced by the patient as uncomfortable breathing or shortness of breath. When obtaining the history, ask what factors precipitate and relieve dyspnea, what level of activity produces dyspnea, and what the patient's body position was when dyspnea occurred
Dyspnea on Exertion (DOE).
- Dyspnea that is associated with activity, such as climbing stairs
- This is usually an early symptom of heart failure and
may be the only symptom experienced by women
- (dyspnea that appears when he or she lies flat). Several pillows may be needed to elevate the head and chest, or a recliner to prevent breathlessness may be used. The severity of orthopnea is measured by the number of pillows or the amount of head elevation needed to provide restful sleep. This symptom is usually relieved within a matter of minutes by sitting up or standing.
Paroxysmal nocturnal dyspnea (PND)
*- Develops after the patient has been lying down for several hours. In this position, blood from the lower extremities is redistributed to the venous system, which increases venous return to the heart.
- A diseased heart cannot compensate for the increased volume and is ineffective in pumping the additional fluid into the circulatory system. Pulmonary congestion results.
- The patient awakens abruptly, often with a feeling of suffocation and panic. He or she sits upright and dangles the legs over the side of the bed to relieve the dyspnea.
- This sensation may last for 20 minutes.*
- May be described as a feeling of tiredness or weariness resulting from activity
- It can also accompany other symptoms or may be an early indication of heart disease in women
- Fatigue resulting from decreased cardiac output is often worse in the evening. Ask whether the patient can perform the same activities as he or she could perform a year ago or the same activities as others of the same age. Often he or she limits activities in response to fatigue and, unless questioned, is unaware how much less active he or she has become.
Best Indicator of Fluid Balance
- 2.2lb = 1kg = 1 L of fluid
- Excess fluid accumulation
- It is possible for weight gains of up to 10 to 15 pounds (4.5 to 6.8 kg, or 4 to 7 L of fluid) to occur before edema is apparent.
- Ask whether the patient has noticed a tightness of shoes, indentations from socks, or tightness of rings.
- Refers to a brief loss of consciousness. The most common cause is decreased perfusion to the brain. Any condition that suddenly reduces cardiac output, resulting in decreased cerebral blood flow, can lead to a syncopal episode. Conditions such as cardiac rhythm disturbances, especially ventricular dysrhythmias, and valvular disorders, such as aortic stenosis, may trigger this symptom
- Refers to dizziness with an inability to remain in an upright position. Explore the circumstances that lead to dizziness or syncope.
Consideration for Older Adults
- Syncope in the aging person may result from hypersensitivity of the carotid sinus bodies in the carotid arteries. Pressure applied to these arteries while turning the head, shrugging the shoulders, or performing a Valsalva maneuver (bearing down during defecation) may stimulate a vagal response. A decrease in blood pressure and heart rate can result, which can produce syncope. This type of syncopal episode may also result from postural (orthostatic) or postprandial (after eating) hypotension.
- May be caused by two conditions: ischemia from atherosclerosis and venous insufficiency of the peripheral blood vessels.
- Patients who report a moderate to severe cramping sensation in their legs or buttocks associated with an activity such as walking have intermittent claudication related to decreased arterial tissue perfusion
- is usually relieved by resting or lowering the affected extremity to decrease tissue demands or to enhance arterial blood flow. Leg pain that results from prolonged standing or sitting is related to venous insufficiency from either incompetent valves or venous obstruction. This pain may be relieved by elevating the extremity.
- Poor cardiac output and decreased cerebral perfusion may cause confusion, memory loss, and slowed verbal responses, especially in older adults.
- Patients with chronic heart failure may also appear malnourished, thin, and cachectic.
- Late signs of severe right-sided heart failure are ascites, jaundice, and anasarca (generalized edema) as a result of prolonged congestion of the liver.
- Heart failure may also cause fluid retention and may be manifested by obvious generalized dependent edema
- Manifested as cool, pale, and moist skin
- Is characteristic of anemia and can be seen in areas such as the nail beds, palms, and conjunctival mucous membranes in any patient
- Involves decreased oxygenation of the arterial blood in the lungs and appears as a bluish tinge of the conjunctivae and the mucous membranes of the mouth and tongue
- May indicate impaired lung function or a right-to-left shunt found in congenital heart conditions.
- Because of impaired circulation, there is marked desaturation of hemoglobin in the peripheral tissues, which produces a bluish or darkened discoloration of the nail beds, earlobes, lips, and toes
- (dusky redness) that replaces pallor in a dependent foot suggests arterial insufficiency
- NORMAL nail bed is 160 degrees
- clubbing is when the nail straightens out to an angle of 180 degrees and the base of the nail becomes spongy
- Systolic pressure of 140 mm HG or higher
- Or a diastolic pressure of 90 mm HG or higher
- Or taking drugs to control BP
- A BP less than 90/60 mm Hg
- May not be adequate for providing enough oxygen and sufficient nutrition to body cells. In certain circumstances, such as shock, the Korotkoff sounds are less audible or are absent. In these cases, palpate the BP, use an ultrasonic device (Doppler device), or obtain a direct measurement by arterial catheter in the critical care setting.
- When BP is palpated, only the systolic pressure can be determined
Postural (orthostatic) hypotension
Occurs when the BP is not adequately maintained while moving from a lying to a sitting or standing position
- It is defined as a decrease of more than 20 mm Hg of the systolic pressure or more than 10 mm Hg of the diastolic pressure, as well as a 10% to 20% increase in heart rate.
- The causes include cardiovascular drugs, blood volume decrease, prolonged bedrest, age-related changes, or disorders of the ANS
To detect orthostatic changes in BP
- First measure the BP when the patient is supine. After remaining supine for at least 3 minutes, the patient changes position to sitting or standing. Normally systolic pressure drops slightly or remains unchanged as the patient rises, whereas diastolic pressure rises slightly. After the position change, wait for at least 1 minute before auscultating BP and counting the radial pulse
jugular venous distention (JVD)
- Observe the venous pulsations in the neck to assess the adequacy of blood volume and central venous pressure (CVP). Specially educated or critical care nurses can assess jugular venous pressure (JVP) to estimate the filling volume and pressure on the right side of the heart. An increase in JVP causes JVD
jugular venous pressure (JVP)
- Right heart failure
- Normally it is 3 to 10 cm H2O. Increases are usually caused by right ventricular failure. Other causes include tricuspid regurgitation or stenosis, pulmonary hypertension, cardiac tamponade, constrictive pericarditis, hypervolemia, and superior vena cava obstruction
Think of the jugular vein as a CVP manometer attached directly to the right atrium. You can "read" the CVP at the highest level of pulsations. Use the angle of Louis (sternal angle) as an arbitrary reference point, and compare it with the highest level of venous pulsations
- Hold a vertical ruler on the sternal angle. Align a straight edge on the ruler like a T-square, and adjust the level of the horizontal straight edge to the level of the pulsations
Auscultation of the major arteries
- necessary to assess for bruits
- have pt lay flat on left side
- are swishing sounds that may occur from turbulent blood flow in narrowed or atherosclerotic arteries.
- Assess for the absence or presence of bruits by placing the bell of the stethoscope on the neck over the carotid artery while the patient holds his or her breath.
- Normally there are no sounds if the artery has uninterrupted blood flow.
- A bruit may develop when the internal diameter of the vessel is
narrowed by 50% or more, but this does not indicate the severity of disease in the arteries
Once the vessel is blocked 90% or greater, the bruit often cannot be heard
- In most settings, the medical-surgical nurse seldom performs precordial palpation and percussion. Critical care nurses and advanced practice nurses are qualified to perform the complete assessment
- Note any prominent pulses
Movement over the aortic, pulmonic, and tricuspid areas is abnormal
- Pulses in the mitral area (the apex of the heart) are considered normal and are referred to as the apical impulse, or the point of maximal impulse (PMI).
- Should be located at the left fifth intercostal space (ICS) in the midclavicular line. If it appears in more than one ICS and has shifted lateral to the midclavicular line, the patient may have left ventricular hypertrophy
- no pulsations, thrills, or heaves palpated except in the mitral area where the apical impulse may be palpated
- The diaphragm of the stethoscope is pressed tightly against the chest to listen for high-frequency sounds and is useful in listening to the first and second heart sounds and high-frequency murmurs. Repeat the progression from the base to the apex of the heart using the bell of the stethoscope, which is held lightly against the chest.
- The bell can screen out high-frequency sounds and is useful in listening for low-frequency gallops (diastolic filling sounds) and murmurs.
First Heart Sound (S1)
- Is created by the closure of the mitral and tricuspid valves (atrioventricular valves)
- When auscultated, S1 is softer and longer; it is of a low pitch and is best heard at the lower left sternal border or the apex of the heart. It may be identified by palpating the carotid pulse while listening. S1 marks the beginning of ventricular systole and occurs right after the QRS complex on the ECG.
Second Heart Sound (S2)
- Is caused mainly by the closing of the aortic and pulmonic valves (semilunar valves)
- S2 is characteristically shorter. It is higher pitched and is heard best at the base of the heart at the end of ventricular systole.
Third Heart Sound (S3)
- Abnormal after 35 years old and represents a decrease in left ventricular compliance. It can be detected as an early sign of heart failure or as a ventricular septal defect
- Is called a ventricular gallop
- (at end)
- May be heard in patients with hypertension, anemia, ventricular hypertrophy, MI, aortic or pulmonic stenosis, and pulmonary emboli. It may be heard also with advancing age because of a stiffened ventricle
Fourth Heart Sound (S4)
- (at beginning)
- Is referred to as atrial gallop
- Reflect turbulent blood flow through normal or abnormal valves.
- They are classified according to their timing in the cardiac cycle: systolic murmurs (e.g., aortic stenosis and mitral regurgitation) occur between S1 and S2, whereas diastolic murmurs (e.g., mitral stenosis and aortic regurgitation) occur between S2 and S1.
- Murmurs can occur during presystole, midsystole, or late systole or diastole or can last throughout both phases of the cardiac cycle.
- They are also graded according to their intensity, depending on their level of loudness
Pericardial friction rub
- Originates from the pericardial sac and occurs with the movements of the heart during the cardiac cycle.
- Rubs are usually transient and are a sign of inflammation, infection, or infiltration.
- They may be heard in patients with pericarditis resulting from MI, cardiac tamponade, or post-thoracotomy
- Squeaky leather
Common and Normal Response Is
Denial, which is a defense mechanism that enables the patient to cope with threatening circumstances
Serum Markers of Myocardial Damage
- Events leading to cellular injury cause a release of enzymes from intracellular storage, and circulating levels of these enzymes are dramatically elevated
- Acute myocardial infarction (MI), also known as acute coronary syndrome, can be confirmed by abnormally high levels of certain proteins or isoenzymes.
- These serum studies are commonly referred to as cardiac markers and include troponin, creatine kinase-MB, and myoglobin
- Is a myocardial muscle protein released into the bloodstream with injury to myocardial muscle.
Troponins T and I are not found in healthy patients, so any rise in values indicates cardiac necrosis or acute MI
T <0.20 ng/mL
I <0.03 ng/mL
Creatine kinase (CK)
- Is an enzyme specific to cells of the brain, myocardium, and skeletal muscle.
- The appearance of CK in the blood indicates tissue necrosis or injury, with levels following a predictable rise and fall during a specified period
- Rise 2 hrs after MI
- Peaks 24 hrs
- a low-molecular-weight heme protein found in cardiac and skeletal muscle
- is the earliest marker detected—as early as 2 hours after an MI with rapid decline after 7 hours
- Because myoglobin is not cardiac specific and is found in skeletal and cardiac muscle, its clinical usefulness is more limited than troponin
less than 200 mg/dL
less than 150 mg/dL
more than 40 mg/dL ("good" cholesterol)
less than 70 mg/dL in high-risk cardiovascular patients, less than 100 mg/dL in patients with moderate risk factors
- Total Cholesterol ,Triglyceride, HDL, LDL
- Taken while fasting
- Is an amino acid that is produced when proteins break down. A certain amount of homocysteine is present in the blood, but elevated values may be an independent risk factor for the development of CVD
- Although the relationship between homocysteine and CVD remains controversial, elevated levels of homocysteine may increase the risk for disease as much as smoking and hyperlipemia, especially in women
Highly sensitive C-reactive protein (hsCRP)
- has been the most studied marker of inflammation
- Inflammation is a common and critical component to the development of atherothrombosis
- Any inflammatory process can produce CRP in the blood.
- Elevations are seen also with hypertension, infection, and smoking.
- A level less than 1 mg/dL is considered low risk; a level over 3 mg/dL places the patient at high risk for heart disease
- Or small amounts of protein in the urine, has been shown to be a clear marker of widespread endothelial dysfunction in cardiovascular disease (along with elevated CRP).
- It should be screened annually in all patients with hypertension, metabolic syndrome, or diabetes mellitus.
- Has also been used as a marker for renal disease, particularly in patients with hypertension and diabetes.
The erythrocyte (red blood cell [RBC]) count
- Is usually decreased in rheumatic fever and infective endocarditis. It is increased in heart diseases as needed to compensate for decreased available oxygen
- Angiography of the arterial vessels, or arteriography, is an invasive diagnostic procedure that involves fluoroscopy and the use of contrast media.
- This procedure is performed when an arterial obstruction, narrowing, or aneurysm is suspected. The interventional radiologist performs selective arteriography to evaluate specific areas of the arterial system
- The most definitive but most invasive test in the diagnosis of heart disease
- May include studies of the right or left side of the heart and the coronary arteries
Patient Preparation with Cardiac Cath
- Tell the patient about the sensations he or she may experience during the procedure, such as palpitations (as the catheter is passed up to the left ventricle), a feeling of heat or a hot flash (as the medium is injected into either side of the heart), and a desire to cough (as the medium is injected into the right side of the heart).
- Written, electronic, or illustrated materials or DVDs may be used to assist in understanding
- Question him or her about any history of allergy to iodine-based contrast agents. An antihistamine or steroid may be given to a patient with a positive history or to prevent a reaction. Be sure that the signed informed consent is completed, as required by The Joint Commission's National Patient Safety Goals (NPSGs)
Complications of Cardiac Catheterization
• Pulmonary embolism
• Vagal response
• Myocardial infarction
• Arterial bleeding or thromboembolism
Right Side of the Heart Cath
- It may be the only side examined. The cardiologist inserts a catheter through the femoral vein to the inferior vena cava or through the basilic vein to the superior vena cava. The catheter is advanced through either the inferior or the superior vena cava and, guided by fluoroscopy, is advanced through the right atrium, through the right ventricle, and, at times, into the pulmonary artery. Intracardiac pressures (right atrial, right ventricular, pulmonary artery, and pulmonary artery wedge pressures) and blood samples are obtained. A contrast medium is usually injected to detect any cardiac shunts or regurgitation from the pulmonic or tricuspid valves.
Left Side of the Heart Cath
- The cardiologist advances the catheter against the blood flow from the femoral or brachial artery up the aorta, across the aortic valve, and into the left ventricle. Alternatively, the catheter may be passed from the right side of the heart through the atrial septum, using a special needle to puncture the septum. Intracardiac pressures and blood samples are obtained. The pressures of the left atrium, left ventricle, and aorta, as well as mitral and aortic valve status, are evaluated. The cardiologist injects contrast dye into the ventricle; cineangiograms (rapidly changing films) evaluate left ventricular motion.
The Technique for Coronary Arteriography
- |s the same as for left-sided heart catheterization. The catheter is advanced into the aortic arch and positioned selectively in the right or left coronary arter
Follow up Care
- After cardiac catheterization, restrict the patient to bedrest and keep the insertion site extremity straight. A soft knee brace can be applied to prevent bending of the affected extremity. Some cardiologists allow the head of the bed to be elevated up to 30 degrees during the period of bedrest, whereas other cardiologists prefer that the patient remain supine. Current practice is for patients to remain in bed for 2 to 6 hours depending on the type of vascular closure device used.
- Monitor the patient's vital signs every 15 minutes for 1 hour, then every 30 minutes for 2 hours or until vital signs are stable, and then every 4 hours or according to hospital policy. Assess the insertion site for bloody drainage or hematoma formation. Complications with vascular closure devices are not common but can be very serious. Assess peripheral pulses in the affected extremity, as well as skin temperature and color, with every vital sign check. Observe for complications of cardiac catheterization
If the patient experiences symptoms of cardiac ischemia
- Such as
chest pain, dysrhythmias, bleeding, hematoma formation, or a dramatic change in peripheral pulses in the affected extremity, contact the Rapid Response Team or physician immediately to provide prompt intervention!
Neurologic changes indicating a possible stroke, such as visual disturbances, slurred speech, swallowing difficulties, and extremity weakness, should also be reported immediately
- The resting ECG provides information about cardiac dysrhythmias, myocardial ischemia, the site and extent of MI, cardiac hypertrophy, electrolyte imbalances, and the effectiveness of cardiac drugs
Electrophysiologic study (EPS)
- Is an invasive procedure during which programmed electrical stimulation of the heart is used to cause and evaluate lethal dysrhythmias and conduction abnormalities
Exercise Electrocardiography (Stress Test)
- (also known as exercise tolerance, or stress test) assesses cardiovascular response to an increased workload.
- The stress test helps determine the functional capacity of the heart and screens for asymptomatic coronary artery disease.
- Dysrhythmias that develop during exercise may be identified, and the effectiveness of antidysrhythmic drugs can be evaluated
Patient Prep for Stress Test
- Because risks are associated with exercising, the patient must be adequately informed about the purpose of the test, the procedure, and the risks involved. Written consent must be obtained.
- Anxiety and fear are common before stress testing
- may have a light meal 2 hours before the test but should avoid smoking or drinking alcohol or caffeine-containing beverages on the day of the test.
- The cardiologist decides whether the patient should stop taking any cardiac medications. Usually, cardiovascular drugs such as beta blockers or calcium channel blockers are withheld on the day of the test to allow the heart rate to increase during the stress portion of the test.
- Patients are advised to wear comfortable, loose clothing and rubber-soled, supportive shoes.
- Remind them to tell the physician if symptoms such as chest pain, dizziness, shortness of breath, and an irregular heartbeat are experienced during the test.
Procedure of Stress Test
- The technician places electrodes on the patient's chest and attaches them to a multilead monitoring system. Note baseline blood pressure (BP), heart rate (HR), and respiratory rate.
- The two major modes of exercise available for stress testing are pedaling a bicycle ergometer and walking on a treadmill.
- the BP and ECG are closely monitored as the resistance to cycling or the speed and incline of the treadmill are increased
The patient exercises until one of these findings occurs:
• A predetermined HR is reached and maintained.
• Signs and symptoms such as chest pain, fatigue, extreme dyspnea, vertigo, hypotension, and ventricular dysrhythmias appear.
• Significant ST segment depression or T wave inversion occurs.
• The 20-minute protocol is completed.
Follow up Care for Stress Test
- Avoid hot shower for 1 to 2 hrs
- For patients who cannot exercise because of conditions such as peripheral vascular disease or arthritis, pharmacologic stress testing with agents such as dobutamine (Dobutrex) may be indicated. The nursing considerations are similar to those for the patient who has undergone an exercise ECG.
- uses ultrasound waves to assess cardiac structure and mobility, particularly of the valves. It helps assess and diagnose cardiomyopathy, valvular disorders, pericardial effusion, left ventricular function, ventricular aneurysms, and cardiac tumors.
- There is
no special preparation for echocardiography.
Inform the patient that the test is painless and takes 30 to 60 minutes to complete. The patient is instructed to lie quietly during the test and on his or her left side with the head elevated 15 to 20 degrees
- Examines cardiac structure and function with an ultrasound transducer placed immediately behind the heart in the esophagus or stomach. The transducer provides especially detailed views of posterior cardiac structures such as the left atrium, mitral valve, and aortic arch
If a Patient Can't Exercise on a Bike or Treadmill
Dipyridamole (Persantine, Apo-Dipyridamole ) or dobutamine hydrochloride (Dobutrex) is administered to simulate the effects of exercise. Tell the patient that these vasodilators may cause flushing, headache, dyspnea, and chest tightness for a few moments after injection.
Identification of the Phlebostatic Axis
1. Position the patient supine.
2. Palpate the fourth intercostal space at the sternum
3. Follow the fourth intercostal space to the side of the patient's chest.
4. Determine the midway point between anterior and posterior.
5. Find the intersection between the midway point and the line from the fourth intercostal space, and mark it with an X in indelible ink. This is the phlebostatic axis.
- Is an invasive system used in critical care areas to provide quantitative information about vascular capacity, blood volume, pump effectiveness, and tissue perfusion.
- It directly measures pressures in the heart and great vessels.
- These procedures are usually performed for more seriously ill patients and can provide more accurate measurements of blood pressure, heart function, and volume status
Hemodynamic Monitoring Risks
- Although complications are uncommon.
- Therefore informed consent is required. After obtaining consent, the nurse prepares a pressure-monitoring system.
- The components of this system are a catheter with an infusion system, a transducer, and a monitor. The catheter receives the pressure waves (mechanical energy) from the heart or the great vessels. The transducer converts the mechanical energy into electrical energy, which is displayed as waveforms or numbers on the monitor. Patency of the catheter is maintained with a slow continuous flush of normal saline, usually infused at 3 to 4 mL/hr under pressure to prevent the backup of blood and occlusion of the catheter.
Hemodynamic Monitoring Procedure
- The physician inserts a balloon-tipped catheter percutaneously through a large vein, usually the internal jugular or subclavian, and directs it to the right atrium (RA). When the catheter tip reaches the RA, the physician inflates the balloon. The catheter advances with the flow of blood through the tricuspid valve, into the right ventricle, past the pulmonic valve, and into a branch of the pulmonary artery. The balloon is deflated after the catheter tip reaches the pulmonary artery. Waveforms are viewed on the monitor as the pulmonary artery catheter is advanced. A chest x-ray is used to check the location
- A pulmonary artery catheter is a multi-lumen catheter with the capacity to measure right atrial and indirect left atrial pressures or pulmonary artery wedge pressure (PAWP)
- During pressure recording, it is important that the transducer be at the level of the phlebostatic axis. The patient is usually supine with the head elevated up to 45 degrees during hemodynamic readings, although the position may not affect results
Complications Associated with Pulmonary Artery Catheters
- Pulmonary infarction or pulmonary rupture may occur if the catheter remains in the wedge position. Air embolism is possible if the balloon has ruptured and repeated attempts are made to inflate it. Ventricular dysrhythmias may occur during insertion or if the catheter tip slips back into the right ventricle and irritates the myocardium. Thrombus and embolus formation may occur at the catheter site. Infection may result, and bleeding may be pronounced if the infusion system becomes disconnected.
Direct Measurement of Arterial BP
- done by invasive arterial catheter in critically ill patients
- After the catheter is inserted, it is attached to pressure tubing.
- A normal saline flush solution is infused constantly under pressure to maintain the integrity of the system.
- A transducer attached to the tubing allows continuous direct monitoring of the arterial BP.
- Direct measurements of BP are usually 10 to 15 mm Hg greater than indirect (cuff) measurements.
- The arterial catheter may also be used to obtain blood samples for arterial blood gas values and other blood tests
Carefully monitor color, pulse, and temperature distal to the insertion site for any early signs of circulatory compromise. Complications of systemic intra-arterial monitoring include pain, infection, arteriospasm, or obstruction at the site with the potential for distal infarction, air embolism, and hemorrhage