Chapter 33 - Assessment of the Cardiovascular System
What physical assessment data is necessary to calculate a pt's cardiac index (CI)? 1. weight & height 2. weight only 3. weight & waist measurement 4. waist measurement & height
Answer: 1 Rationale 1: Cardiac index (CI) is the cardiac output adjusted for the pt's body size or body surface area. Body surface area is calculated using height & weight measurements. Rationale 2,3,4: Body surface area is calculated using height & weight measurements.
Which of the following would be an example of the term cardiac reserve? 1. getting on a treadmill & gradually increasing the pace of walking 2. breathing in through the nose & out the mouth while sitting quietly 3. sitting in a chair, to cool down, after having completed an exercise routine 4. at the end of systole, approximately 50 mL of blood remains in the ventricles
Answer: 1 Rationale 1: The heart's ability to respond to the body's changing need for cardiac output is called cardiac reserve. Increasing the pace of walking would place demand on the heart to increase blood flow. Rationale 2,3,4: The other options do not place demand on the heart.
When auscultating the chest of a 75-year-old pt who recently experienced a myocardial infarction (MI), the nurse hears an S3 heart sound immediately following S2. Because of these findings, the nurse would assess for which other condition? 1. extension of the MI 2. heart failure 3. renal failure 4. liver failure
Answer: 2
A pt comes into the health clinic asking for advice on lowering the individual's risk of heart disease. The nurse's best response is to do which of the following? 1. Conduct a physical exam of the pt & discuss the findings. 2. Conduct a health history & physical exam to determine the pt's area of risks & then educate the pt based upon these findings. 3. Determine the pt's risks based upon a prior chart for the pt. 4. Discuss the pt's perceived area of health risks.
Answer: 2 Rationale 2: A thorough health history & physical exam should disclose a pt's risk factors. Rationale 1: Conducting a physical exam would discover some risk factors, but is not inclusive of the health history. Rationale 3: Using the pt's old chart may disclose some risk factors, but would not include any recent concerns. Rationale 4: Discussing the pt's perceived area of health risks will not be inclusive & may only capture those risks the pt is aware of. Modifiable risk factors can be evaluated & discussed w/ the pt.
A pt being evaluated for cardiac pathology asks the nurse why sodium, calcium, & potassium are so important in his diet. What is the nurse's best response? 1. "Because you are on potassium supplements, it is important to monitor electrolytes." 2. "Heart rate is affected by the oxygen levels in your body, which involves the attachment of oxygen molecules to these electrolytes." 3. "It is the pacemaker of your heart that is responsible for the heart beat." 4. "The action potentials of the heart muscle cells are dependent upon the diffusion of sodium, potassium & calcium across the cell membrane."
Answer: 4 Rationale 4: Action potentials of the cardiac muscle involve shifts in potassium, calcium, & sodium across the cell membrane. Rationale 1: There is not enough data to justify. Rationale 2: Oxygen molecules attach to the hemoglobin molecule, not electrolytes. Rationale 3: The pacemaker is responsible for the heartbeat but this response does not answer the pt's question.
Determine the cardiac output (CO) of a pt whose stroke volume (SV) is 80 mL/beat & whose heart rate (HR) is 75 beats/minute. Round to the nearest whole number & place the answer below. _______
Answer: 6000 Rationale : Cardiac output is the amount of blood pumped by the ventricles into the pulmonary & systemic circulations in one minute. It is determined by multiplying the stroke volume by the heart rate (SV × HR = CO). Multiplying 80 mL/beat by 75 beats/minute equals 6000 mL.
An important nutritional-metabolic interview question to ask pts who are being evaluated for heart conditions is which of the following? 1. "Have you had a recent weight gain or loss?" 2. "Is there any change in your usual bowel elimination?" 3. "Has there been a change in your usual daily activities?" 4. "Have you experienced chest pain in the last week?"
Correct Answer: 1 Rationale 1: Weight gain can be linked to abnormal retention of fluids, which can affect heart function. Weight loss can be linked to level of nutrition or dehydration. The nutritional-metabolic functional health pattern guides questions that are related to weight gain or loss. Rationale 2:?'s regarding elimination are important but are categorized under other functional health patterns. Rationale 3: ?'s regarding daily activity are important but are categorized under other functional health patterns. Rationale 4: ?'s regarding chest pain are important but are categorized under other functional health patterns.
A pt is scheduled for a cardiac ejection fraction (EF) study. Correct facts that guide pt teaching include which of the following? Select all that apply. 1. Stroke volume times heart rate equals cardiac output. 2. The effectiveness of the pumping action of the heart is evaluated. 3. The study measures the percentage of blood in the ventricle ejected during a heartbeat. 4. The normal ejection fraction is 95-100%. 5. The study identifies the ischemic areas of the heart.
Correct Answer: 1,2,3 Rationale 4: The normal ejection fraction is 50-75%. Rationale 5: An ischemic area of the heart is not identified during an EF study.
The primary factor regulating blood flow through the coronary arteries is which of the following? 1. blood vessel dilation 2. the low pressure systemic circulation 3. blood pressure in the aorta 4. the draining of blood into the coronary sinus by the coronary veins
Correct Answer: 3 Rationale: Blood flow through the coronary arteries is primarily regulated by the aortic BP. Other factors include the blood vessel tone (constriction), HR, & metabolic activity of the heart.
A chronotropic medication like digoxin affects: A. contractility B. cardiac reserve C. preload D. afterload
a. contractility
Cardiac output is determine by the rate the heart is beating times its stroke volume. What 3 specific factors affect stroke volume? A. Cardiac reserve B. Contractility C. Preload D. Afterload
b, c, d
What factor will cause a decrease in cardiac output (CO)? a. Decreased afterload b. Decreased heart rate (HR) c. Increased stroke volume (SV) d. Decreased systemic vascular resistance (SVR)
b. Decreased heart rate (HR) causes decreased cardiac output (CO). The other options contribute to an increased CO.
A patient has significant atherosclerosis. The nurse knows that this affects his cardiac output because it: A. Affects contractility B. Affects the afterload C. Affects preload D. Affects cardiac reserve
b. afterload Afterload is affected by the size of the ventricle, wall tension, and arterial blood pressure.
During hemodynamic monitoring, the nurse finds that the patient has a decreased CO with unchanged pulmonary artery wedge pressure (PAWP), HR, and SVR. The nurse identifies that the patient has a decrease in what? a. Preload b. Afterload c. Contractility d. Stroke volume
c. CO is dependent on HR and SV. SV is determined by preload, afterload, and contractility. If CO is decreased and HR is unchanged, SV is the variable factor. If the preload (determined by pulmonary artery wedge pressure [PAWP]) and the afterload (determined by SVR) are unchanged, the factor that is changed is the contractility of the myocardium.
The patient has experienced an increased preload, which supports an increase in CO. What nursing action contributes to an increased preload? a. Diuretic administration b. Intropin administration c. Increased fluid administration d. Calcium channel blocker administration
c. Increased fluid administration increases preload, which will increase CO. Diuretics will decrease preload. Intropin (dopamine) does not affect preload but increases CO with increased cardiac contractility. Calcium channel blockers do not affect preload but decrease contractility