Download Smeltzer Textbook of Medical Surgical Nursing

Chapter 25
Assessment of
Cardiovascular Function
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Overview of Anatomy and Physiology
• Three layers:
endocardium,
myocardium, epicardium
• Four chambers: Right
atrium and ventricle, left
atrium and ventricle
• Atrioventricular valves:
tricuspid and mitral
• Semilunar valves: aortic
and pulmonic
• Coronary arteries
• Cardiac conduction
system
(electrophysiology)
• Cardiac hemodynamics
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Anatomy of the Heart
Figure 25-1
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Cardiac Conduction System:
Electrophysiology
(60-100)
(40-60)
(30-40)
(30-40)
Figure 25-3
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Question
Which of the following is the primary pacemaker for the
myocardium?
A. Atrioventricular junction
B. Bundle of His
C. Purkinje fibers
D. Sinoatrial node
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Answer
D. Sinoatrial node
Rationale: The sinoatrial node is the primary pacemaker
for the myocardium.
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Cardiac Action Potential
• Depolarization: electrical activation of cell caused by
influx of sodium into cell while potassium exits cell
• Repolarization: return of cell to resting state caused by
reentry of potassium into cell while sodium exits
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Cardiac Action Potential (cont’d)
• Refractory periods
– Effective refractory period: phase in which cells are
incapable of depolarizing
– Relative refractory period: phase in which cells
require stronger-than-normal stimulus to depolarize
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Cardiac Action Potential Cycle
Figure 25-4
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Greater Vessels, Heart Chambers and
Pressures
Figure 25-2
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Cardiac Hemodynamics
• Stroke volume(SV): amount of blood ejected with each
heartbeat
– Preload: degree of stretch of cardiac muscle fibers at
end of diastole
– Afterload: resistance to ejection of blood from
ventricle
– Contractility: ability of cardiac muscle to shorten in
response to electrical impulse
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Cardiac Hemodynamics (cont’d)
• Ejection fraction: percent of end diastolic volume ejected
with each heart beat (left ventricle)
• Cardiac utput (CO): amount of blood pumped by
ventricle in liters per minute.
• CO = SV × HR
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Influencing Factors
• Control of heart rate
– Autonomic nervous system, baroreceptors
• Control of stroke volume
– Preload: Frank-Starling Law
– Afterload: affected by systemic vascular resistance,
pulmonary vascular resistance
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Contractility
– Contractility increased by catecholamines, SNS,
some medications
– Decreased by hypoxemia, acidosis, some
medications
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Question
Which of the following best defines stroke volume?
A. The amount of blood ejected with each heartbeat
B. Amount of blood pumped by the ventricle in liters per
minute
C. Degree of stretch of the cardiac muscle fibers at the
end of diastole
D. Ability of the cardiac muscle to shorten in response to
an electrical impulse
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Answer
A. The amount of blood ejected with each heartbeat
Rationale: Stroke volume is the amount of blood ejected
with each heartbeat. Cardiac output is the amount of
blood pumped by the ventricle in liters per minute.
Preload is the degree of stretch of the cardiac muscle
fibers at the end of diastole. Contractility is the ability of
the cardiac muscle to shorten in response to an electrical
impulse.
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Health History
• Demographic information
• Family/genetic history
• Cultural/social factors
• Risk factors
– Modifiable
– Nonmodifiable
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Most Common Clinical Manifestations
• Chest pain
• Dyspnea
• Peripheral edema, weight gain
• Fatigue
• Dizziness, syncope, changes in level of consciousness
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Question
Where does the nurse auscultate the apex of the heart?
A. Erb’s point
B. Fifth intercostal space
C. Pulmonic area
D. Tricuspid area
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Answer
B. Fifth intercostal space
Rationale: The nurse auscultates the apex of
the heart at the left fifth intercostal space at
the midclavicular line.
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Assessment
• Physical examination
• Palpation, percussion, auscultation
• Medications
• Nutrition
• Elimination
• Activity, exercise
• Sleep, rest
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Assessment (cont’d)
• Vital signs
• Self-perception, self-concept
• Roles, relationships
• Sexuality, reproduction
• Coping, stress tolerance
• Prevention strategies
• Family history
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Health Promotion, Perception, and
Management Questions
• Ask regarding health promotion, preventive practices
– What type of health issues do you have? Are you
able to identify any family history or behaviors that
put you at risk of this health problem?
– What are your risk factors for heart disease? What do
you do to stay healthy?
– How is your health? Have you noticed any changes?
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Health Promotion, Perception, and
Management Questions (cont’d)
• Ask regarding health promotion, preventive practices
– Do you have a cardiologist or primary health care
provider? How often do you go for checkups?
– Do you use tobacco or alcohol?
– What medications do you take?
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Laboratory Tests
• Cardiac biomarkers
• CK, CK-MB
• C-reactive protein
• Myoglobin
• Troponin T and I
• Lipid profile
• Brain (B-type) natriuretic
peptide
• Homocysteine
• Refer to Table 25-4
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Electrocardiography
• 12-lead ECG
• Continuous monitoring: hardwire, telemetry
• Signal-averaged ECG
• Continuous ambulatory monitoring
• Transtelephonic monitoring
• Wireless mobile monitoring
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Electrocardiography (cont’d)
• Cardiac stress testing
– Exercise stress testing
– Pharmacologic stress testing
• Echocardiography
–
Transthoracic
– Transesophageal
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Diagnostic Tests
• Radionuclide imaging
– Myocardial perfusion imaging
– Test of ventricular function, wall motion
– Computed tomography
– Positron emission tomography
– Magnetic resonance angiography
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Cardiac Catherization
• Invasive procedure study used to measure cardiac
chamber pressures, assess patency of coronary arteries
• Requires ECG, hemodynamic monitoring; emergency
equipment must be available
• Assessment prior to test; allergies, blood work
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Cardiac Catherization (cont’d)
• Assessment of patient postprocedure; circulation,
potential for bleeding, potential for dysrhythmias
• Activity restrictions
• Patient education pre- and postprocedure
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Hemodynamic Monitoring
• CVP
• Pulmonary artery pressure
• Intra-arterial BP monitoring
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Phlebostatic Level
Figure 25-10
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
Pulmonary Artery Catheter and Pressure
Monitoring System
Figure 25-12
Copyright © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins