Cardiovascular Diagnostic Tests and Procedures Flashcards
Purposes of medical tests
- Facilitate the achievement of a correct diagnosis
- Aid in the prevention of complications
- Develop information to determine a prognosis
- Identify subclinical disease states
Define Sensitivity
- Proportion of individuals with the disease who have a true positive test
Define Specificity
- Proportion of individuals w/o the disease with a true negative test
Describe positive versus negative predictive values
- Positive: proportion of individuals who had a positive test & actually have the disease
- Negative: proportion of individuals who had a negative test & truly do not have the disease
Serum enzymes and cardiac biomarkers may aid in assessing the _________________ or the _________________
- Degree of myocardial damage
- Effectiveness of reperfusion
Serum Enzymes and Cardiac Biomarkers that are most commonly used for the diagnosis of cardiac injury
- Creatine kinase (CK-MB isoenzyme): abnormal if >5%
- Troponins: gold standard for assessing myocardial damage
Describe acute coronary syndrome (ACS)
- Unstable anginia: absences of cardiac myocyte death
- MI: STEMI resulted from total occlusion thrombus and NSTEMI resulted from partial occlusion with/without collateral circulation
Define myoglobin
- Heme protein found in all muscle tissue; potential diagnostic tool for acute MI
Define B type natriuretic peptide (BNP)
- Protein produced by the ventricles of the heart used in diagnosing heart failure, with implications for CAD
Enzyme and isoenzyme levels increase within the first _______ hours after myocardial injury and reach their individual peaks at different rates
- 2 to 6 hours
BNP lab values
- Normal: <100
- Pro BNP normal: <300
- Heart failure likely if >400
What is considered a major risk factor for CAD in the blood
- Hyperlipidemia (elevation in blood lipid levels)
Serum cholesterol and triglycerides are blood lipids of concern when elevated
- Elevated cholesterol is associated with ingestion of excess amounts of saturated fat and cholesterol
- Elevated triglyceride levels are defined as being higher than 150 mg/dL
Highly sensitive C-reactive protein (hs-CRP) assay is available to determine heart disease risk
- Normal/low risk: <1.0
- Average: 1.0-3.0
- High risk: >3.0
What 3 components are included in a complete blood cell count test
- White blood cells (WBC)
- Hemoglobin (Hb)
- Hematocrit
Hemoglobin (Hb) below what value is a red flag for out of bed activity
- <8
Hematocrit is a significant indicator of the viscosity of the blood; list the implications for elevated/low lab values
- Critically low Hb and hematocrit (<15-20%) may lead to cardiac failure or death
- Hb values >20 or hematocrit >60% will increase viscosity of the blood causing increased resistance & stress on the heart
Prothrombin time and partial thromboplastin time measure ___________
- Coagulation of blood
Electrolytes involved in maintaining cell membrane potential that are most important to monitor
- Sodium (Na)
- Potassium (K)
- Magnesium (Mg)
Patients receiving diuretics (e.g., for hypertension or heart failure) should have their ________ and ________ levels monitored carefully because some diuretics act on the kidney
- Sodium and potassium
Critical values and implications for sodium levels
- Critical: <120 or >160
- Hypernatremia:thrist, confusion, irritability, hyperreflexia, seizure, coma, tachycardia, hypotension, oliguria
- Hyponatremia: HA, lethargy, hyporeflexia, seizure, coma, OH, pitting edema, confusion, weakness, nausea
Critical values and implications for potassium levels
- Critical: Newborn -> <2.5 or >8; Adult -> <2.5 or >6.5
- Hyperkalemia: muscle weakness or paralysis, muscle tenderness, paresthesia, dysrhythmia, bradycardia
- Hypokalemia: extremity weakness, hyporeflexia, paresthesia, leg cramps, dysrhythmia, hypotension
Critical values and implications for magnesium levels
- Critical: <0.5 or >3
- Hypermagnesemia: N/V, hyporefelxia, hypotonia, somnolence (drowsy), bradycardia, dysrhythmia, hypotension, respiratory depression
- Hypomagnesemia: hypertonia, hyperreflexia, tremors, muscle cramping, seizures, apathy, nystagmus, dysrhythmias
Elevated BUN may indicate
- renal failure, uremia, or retention of urea in the blood
- Unsuitable as a single measure for renal disease; creatine value should also be noted
Critical values and implications for serum creatine levels
- Critical: >4 indicates serious impairment in renal function
- Elevated: edema, dyspnea, abdominal/back pain, arthralgia, myalgia, myopathy, fatigue/malaise, insomnia, HA, confusion, pruiritis
- Low: fatigue (uncommon)
Normal glucose levels
- Fasting normal: 90-130
- Elevated 120-130 suggests prediabetic states & warrants further testing for DM
- Hyperglycemia: >200 denotes a crisis situation requiring immediate insulin (should not exercise)
- Normal A1C: <5.7%
Symptoms of hyper/hypo glycemia
- Hyper/Ketoacidosis: N/V, fruity breath, confusion, weak/rapid pulse, kussmaul respiration
- Hypoglycemia: perspiration, weakness, pallor, nervousness, seizure, lethargy, irritability, tachycardia, palpitation, altered mental status, hunger, HA, shaking, blurred vision, LOC
Describe Holter monitoring
- Continuous 24hr ECG monitoring of heart rhythm
- PT should obtain interpretation of results to determine whether modifications are needed in the pt’s activities
- Pts with abnormal Holter monitor results may be referred for treadmill exercise testing to assess arrhythmia or for echocardiography to assess valve functioning
Patients demonstrating _________________ with ambulatory monitoring may be referred to electrophysiologic mapping studies (EPS)
- Life threatening arrhythmias
Describe an echocardiography
- Provides real time images of beating heart
- Uses pulses or reflected ultrasound to evaluate functioning of the heart
- Transducer is placed on chest wall at the 3rd-5th intercostal space near L sternal border
Information that can be obtained from the echocardiogram
- Size of ventricular cavity
- Thickness/integrity of inter arterial/ventricular septa
- Function of valves
- Motions of ventricular wall
- Degree of normal thickening of the myocardium
Advantages and disadvantages of a PET (position emission tomography)
- Direct measurement of metabolic function & blood flow of the heart
- Advantages: gold standard for blood flow, detects jeopardized but viable myocardium w/o exercise
- Disadvantages: requires specialized tech & highly trained staff, costly & not available at many hospitals
What can different types of CT scans show in the heart
- Used to identify masses in cardiovascular system or to detect aortic aneurysms or pericardial thickening
- Single-photon emission computed tomography (SPECT)—detects and quantifies myocardial perfusion defects and contractility defects
- Electron beam computed tomography—detects calcium in coronary arteries and quantifies coronary atherosclerosis
Describe a Multigated acquisition imaging (MUGA)
- Calculates L ventricular ejection fraction (LVEF)
- Radioactive tracer injected intravenous & gamma camera acquires images
Describe MRI of the heart
- Evaluates morphology, cardiac blood flow, and myocardial contractility
- Similar diagnostic accuracy as PET imaging, but more available and less expensive
Describe MRA (magnetic resonance angiogram)
- uses magnetic and radio wave energy to take pictures of blood vessels
Most common agents used for a pharmacological stress test
- Adenosine
- Dipyridamole
- Dobutamine
- Regadenoson
- Adenosine or dipyridamole-walk protocol—combined low-level treadmill exercise during adenosine infusion
General goals of cardiac catheterization
- Establish or confirm a diagnosis of cardiac dysfunction or heart disease.
- Demonstrate the severity of CAD or valvular dysfunction.
- Determine guidelines for optimal management of the patient, including medical and surgical management and a program of exercise
Data obtained from cardiac catheterization
- Cardiac output
- Shunt detection
- Angiography (coronary and ventriculography
- L and R heart pressures (hemodynamics)
- Ventricular ejection fraction (normal ~65)
What are the normal pressure in the L/R segments of the heart
- Right atrial (normal = 0–4 mm Hg)
- Right ventricle (normal = 30/2 mm Hg)
- Pulmonary artery (normal = 30/10 mm Hg)
- Pulmonary artery wedge (normal = 8–12 mm Hg)
- Left ventricular end-diastolic (normal = 8–12 mm Hg)
Specific determinations that can be made from cardiac catheterization
- The presence of and severity of CAD (degree of stenosis)
- Presence of left ventricular dysfunction or aneurysm or both
- Presence of valvular heart disease and the severity of the dysfunction
- The presence of pericardial disease
Cardiac catheterization has greater predictive accuracy in assessment of __________ than exercise testing
- CAD (coronary artery disease)
What does an endocardial biopsy determine
- Determines myocardial rejection in patients with a cardiac transplant
Most common dysfunctions/diagnostic tests for aortic dysfunctions
- Dysfunctions: aneurysms, atherosclerotic disease, aortic valve dysfunction, arteritis
- Diagnostic tests: ECG, angiography, CT scan, & chest x-ray
Current methods to determine presence of peripheral arterial disease (PAD) include
- History of symptoms
- History of risk factors for atherosclerotic disease
- Physical examination of pulses
- Use of noninvasive vascular tests
ABI (ankle brachial index) levels
- No symptoms/normal: >1.1
- Claudication: 0.5-1.0
- Critical limb ischemia: 0.2-0.5 (suggestive of severe arterial occlusive disease)
- Severe ischemia: <0.2
Arterial duplex ultrasonography is a more precise diagnostic test for defining _________ and __________
- Arterial stenosis
- Occlusions
Claudication often limits activity before any cardiac symptoms are evoked, so a graded exercise test may not be an effective method of evaluating cardiac disease if patients have PAD (True/False)
- True
Define Rubor dependency test and Venous filling time test
- Rubor: assesses LE arterial circulation using skin color changes and positional changes
- Venous: measures the efficiency of arterial blood flow through the capillaries and into the veins
Direct visualization with duplex ultrasonography can identify the following
- Plaque
- Stenosis
- Occlusions in the internal, common, & external carotid arteries
- Flow direction in the vertebral arteries
Typical arterial blood gases (ABG) report contains the following
- Arterial pH
- Partial pressures of carbon dioxide(PaCO2)
- Partial pressures of oxygen (PaO2)
- Oxygen saturation (SaO2)
- Bicarbonate (HCO3−) concentration
- Base excess
What does a blood gas analysis assess
- Assesses problems related to acid-base balance, ventilation, & oxygenation
Adequacy of alveolar ventilation: reflected by PaCO2
- Hyperventilation—PaCO2 < 40 mm Hg
- Hypoventilation—PaCO2 > 40 mm Hg
- Ventilatory failure—PaCO2 > 50 mm Hg
Normal and abnormal pH levels in the blood
- Normal: 7.35-7.45
- pH <7.35 is acidemia: Low HCO3- leads to metabolic acidosis and High PaCO2 = respiratory acidosis
- pH >7.45 is alkalemia: High HCO3- is metabolic alkalosis and Low PaCO2 is respiratory alkalosis
Presentation of respiratory Alkalosis (increase pH, decrease PaCO2, normal HCO3-)
- Lightheaded
- Dyspnea
- Paresthesia
- Chest tightness
- Seizure
Presentation of respiratory Acidosis (decrease pH, increase PaCO2, normal HCO3-)
- Anxiety
- Confusion
- Fatigue/lethargy
- Tachypnea
- Coma
- Seizure
Presentation of metabolic Alkalosis (increase pH, normal PaCO2, increase HCO3-)
- Confusion
- Delirium
- Dysrhythmias
- Hypotension
- Muscle cramping
Presentation of metabolic Acidosis (decrease pH, normal PaCO2, decrease HCO3-)
- Dyspnea (Kussmaul breathing)
- Fatigue
- Nausea/vomiting
- Tachyarrhythmias
- Hypotension
Compensated versus uncompensated respiratory acidosis
- Uncompensated: PaCO2 levels increase without a corresponding change in HCO3- levels.This can be caused by type II respiratory failure, which can be due to CNS disorders, neuropathy, or myopathy.
- Compensated: PaCO2 levels increase, and HCO3- levels also increase, which helps to balance the pH within the normal range.
Compensated versus uncompensated metabolic acidosis
- Uncompensated: Increased HCO3- without an increase in PaCO2
- Compensated: pH is within normal range, decreased HCO3- with decreased PaCO2
Normal pH, PaCO2, and HCO3- values
- pH: 7.35-7.45
- PaCO2: 35-45
- HCO3-: 23-27
Describe the anion gap
- A blood test to determine the difference between free cations and frees anions
- Free cations: Sodium (Na) and Potassium (K)
- Free anions: Chloride (Cl) and Bicarbonate (HCO)
Pulmonary function tests (PFTs) provide information about the
- Integrity of airways
- Function of respiratory musculature
- Condition of lung tissues
Describe a body plethysmograph
- Pt sits in airtight chamber
- Determines how much air is in lungs after taking a deep breath
- Also measures amount of air left in lungs after person exhales as much as possible
TLC (total lung capacity) always __________ in obstructive lung diseases and _________ in chronic restrictive lung diseases
- Elevated
- Reduced
Define forced vital capacity
- Forced vital capacity (FVC): maximum volume of gas the patient can exhale as forcefully and quickly as possible
Define force expiratory volume in 1 second (FEV1)
- Force expiratory volume in 1 second (FEV1): volume of air exhaled during the first second of the FVC; reflects airflow in the large airways
Define forced midexpiratory flow (FEF 25-75)
- Forced midexpiratory flow (FEF25-75): volume of air exhaled over the middle half of the FVC, divided by the time required to exhale it
Define forced expiratory flow, 200-1200 (FEF200-1200)
- Forced expiratory flow, 200 to 1200(FEF200–1200): the average expiratory flow during the early phase of exhalation
Define maximum voluntary ventilation (MVV)
- Maximum voluntary ventilation (MVV): maximal volume of gas a patient can move during 1 minute-
Define peak expiratory flow (PEF)
- Peak expiratory flow (PEF): maximum flow that occurs at any point in time during the FVC
Define the Diffusing capacity of lung (DL) or diffusing capacity of lung for carbon monoxide (DLCO)
- The amount of gas entering the pulmonary blood flow per unit of time relative to difference between partial pressures of gas in alveoli and pulmonary blood
- DL measures integrity of functional lung unit.
Abnormal values of DLCO test attributed to three factors
- Decreased quantity of hemoglobin per unit volume of blood
- Increased “thickness” of the alveolar–capillary membrane
- Decreased functional surface area available for diffusion
Severity and classification of DLCO reduction
- Normal DLCO: >75% of predicted, up to 140%
- Mild: 60%to LLN (lower limit of normal)
- Moderate: 40%to 60%
- Severe: <40%
During a flow-volume loop following a period of normal, quiet breathing, the patient is instructed to
- Perform a maximal inspiratory maneuver
- Hold the breath for 1 to 2 seconds
- Do an FVC maneuver
- Do another maximal inspiratory maneuver
Slide 85
What does the BODE index for COPD estimate
- Estimates 4 year survival
Slides 90-92
Standard radiograph, or chest x-ray (CXR), provides a static view of chest anatomy that is used to
- Screen abnormalities
- Provide baseline for further assessments
- Monitor progress of a disease process or treatment
How does air and bone present on chest x-ray
- Air in the lungs results in a dark image (radiolucency).
- Bone results in a white image (radiopacity).
What are the 2 standard views for a chest x-ray
- Posteroanterior (PA): patient in standing position with the front of the chest facing the film cassette
- Left lateral view: helpful in localizing the position of an abnormality
Describe a decubitus, lordotic, oblique, and anteroposterior (AP) views in a chest x-ray
- Decubitus: taken to confirm the presence of an air– fluid level in the lungs or a small pleural effusion
- Lordotic: used to visualize the apical or middle region of lungs or to screen for pulmonary tuberculosis
- Oblique: taken to detect pleural thickening, to evaluate the carina, or to visualize the heart and great vessels.
- Anteroposterior (AP) view: taken at the patient’s bedside
CT scanning of chest primarily used for diagnosis of ________ versus calcifications or nodules
- Tumors
Describe a high-resolution computed tomography of the lungs (HRCT)
- Detects diseases of the lung parenchyma
- Detects lung disease in symptomatic patients with normal chest radiograph
What is the gold standard for diagnosing a pulmonary embolism (PE)
- Pulmonary arteriography
Due to the disadvantages of pulmonary arteriography what imaging has become more widely used to test for PE
- Chest CT scan
Chest MRI is primarily indicated for evaluation of ______________________
- Chest wall processes
Normal V/Q scans show ________ ventilation and perfusion in the bases of the lung and ________ ventilation and perfusion in the apices.
Perfusion defects with normal ventilation strongly suggest a ______________________
- Greater; less
- Pulmonary embolism (PE)
Bronchography is used for
- Evaluation and management of some congenital pulmonary anomalies & acquired disease (usually of the tracheobronchial tree)
Describe a bronchoscopy
- Fiberoptic bronchoscopy permits direct visualization of previously inaccessible areas of the bronchial tree.
- Usually performed with a flexible fiberoptic tube inserted through mouth or nose
