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