Perfusion Flashcards
What does the pulmonary circuit include
?
right side of the heart, the pulmonary arteries, lungs, and the pulmonary capillaries
Why can an increase in pressure in the left side of the heart cause increased pulmonary vascular pressures and pulmonary edema?
Pulmonary veins have no valves and blood can back up into the lungs through the pulmonary veins
Which layer of a blood vessel prevents clotting and damage to blood cells?
tunica intima (specifically the smooth muscle in the endothelium)
Which layer of arteries is much thicker than veins?
tunica media
What is a major purpose of the pulmonary circuit?
Facilitate external gas exchange
What kind of system is seen in the systemic circuit?
a high-pressure system
Which blood vessel layer interfaces directly with the blood?
Tunica intima
The large arteries are able to adjust their size in response to the cardiac cycle for which reason?
An abundance of elastic fibers in the tunica media
Which atrium receives deoxygenated blood from the body?
Right atrium
Which atrium will receive oxygenated blood from the lungs?
left atrium
What is the innermost layer of the heart?
endocardium
What are the two layers of the pericardial sac?
parietal pericardium and visceral pericardium
What are the first vessels to receive CO after blood is leaving the left ventricle?
coronary arteries
Which coronary artery supplies the right ventricle?
right coronary artery
What does the left anterior descending artery supply?
the anterior aspect of the left ventricle and septum
What regulates the blood flow through the coronary arteries and the perfusion of the myocardium?
aortic pressure
The endocardium has which major function?
Provide a protective surface for direct exposure to blood cells
What is a unique property of cardiac muscle?
It has an abundant amount of myoglobin.
What is the major purpose of the heart valves?
Prevent the backward flow of blood
How is the term cardiac cycle best defined?
Heart muscle activities during one complete heartbeat
What does CI (cardiac index) take into account that CO does not?
BSA
4 determinants of CO
heart rate, preload, after load, and contractility
What is stroke volume?
the volume of blood pumped with each heartbeat
What is the stretch in the myocardial fibers at the end of diastole? And what does it represent?
preload, represents the volume of blood in the ventricle at the end of diastole
What is the Frank-Starling law of the heart?
the heart will pump the amount of blood it receives with each beat (until it meets the physiological limit)
The more the cardiac muscle is stretched during diastole, the stronger the contraction is during systole
What is afterload?
the resistance against which the ventricles must overcome to pump blood
the ventricular pressure after systole
What is Ohm’s law?
Pressure= Flow x Resistance
If calcium is increased, what will happen to the heart’s contraction?
it will result in a greater contraction
What are factors that influence contractility known as?
inotropes
If after load increases, stroke volume _____.
decreases
What is the measure of the percent of blood ejected with each stroke volume known as?
Ejection fraction
A client has developed a heart rate of 150 bpm. This would have which effect on cardiac output?
Decrease
A client with a normal heart has developed increased preload. This will result in which hemodynamic change?
Increase in stroke volume
In a client with normal heart function, if blood pressure decreases and flow remains unchanged, peripheral resistance will change in which way to increase the blood pressure?
It will increase
Which conditions, if present in the client, can result in decreased afterload?
Septic shock
Depressed sympathetic NS
Vasodilating drugs
How is arterial pressure calculated?
peripheral resistance times cardiac output
Why does renin go up when blood pressure decreases?
the kidneys cannot be perfused well and this triggers renin release
How can the kidneys alter BP?
the RAAS system and through retention of water
How is the term systemic filling pressure best defined?
The amount of force available to return blood to the heart
Which statement correctly describes how the renin-angiotensin-aldosterone system (RAAS) alters blood pressure?
Angiotensin II stimulates the release of aldosterone
When baroreceptors sense a blood pressure that is below the individual’s normal preset level, which set of actions is triggered?
Increased heart rate, vasoconstriction
What is often described as a “skipping” or “thumping” of the heart by the patient?
palpitations
What is used to estimate the 10 year risk of atherosclerotic cardiovascular disease?
Pooled Cohort equations
What is the precordium?
the region of the thorax immediately in front of the heart
Why does jugular venous distention happen?
backflow through the vena cava as a result of retention of blood in the right side of the heart during right sided HF
What value will increase after an MI? How long does it take for this increase to happen?
CK-MB within 4-6 hours following an MI
What is the leading laboratory value that assesses for myocardial damage?
troponin
When is C-reactive protein released?
during systemic inflammation, infection, and tissue damage
What is a high BNP associated with?
HF
S3 heart sound caused by decreased ventricular compliance are called what?
ventricular gallop
he nurse is assessing a client who is complaining of chest pain, using the PQRST assessment format. The “S” in this mnemonic refers to which assessments?
Timing and treatment strategies
Which cardiac enzyme appears in the blood within 3 hours of myocardial cell death?
Troponin
Decreased contractility is manifested by which signs?
Diminished pulse pressure
Which signs indicate possible increased afterload for the left ventricle?
Cool, clammy extremities, non-healing wounds, HTN, thick, brittle nails, slow cap refill
What does stress testing assess?
the heart’s response to increased oxygen demand
What are 3 invasive diagnostic procedures used to assess cardiac health?
transesophageal echocardiogram (TEE), cardiac catheterization, and electrophysiology study (EPS)
the procedure of choice to detect clots in the left atrium, atrial septal defects, infections on valve leaflets, and valve dysfunction.
Transesophageal Echocardiogram (TEE)
gold standard for assessment of coronary arteries
Cardiac Catheterization
Left-heart catheterization is performed primarily to determine what?
the patency of the coronary vessels
The findings from this study help to determine if the patient would benefit from further interventions, such as drug therapy, implanted pacemaker or implantable cardio-defibrillator, or ablation
Electrophysiology Study (EPS)
What happens during an EPS?
Under fluoroscopy, electrode catheters are inserted into the heart. These catheters conduct electrical impulses to and from the heart to trigger abnormal heart rhythms; these dysrhythmias usually disappear after removal of the electrical stimuli
The nurse preparing a client for cardiac catheterization must notify the cardiologist with which information?
The client reports an allergy to shellfish.
After a cardiac catheterization, the nurse must monitor for which primary complication?
Bleeding
The electrophysiology study (EPS) is used for which purpose?
To classify and locate cardiac arrhythmias
What are the 3 components of stroke volume?
preload, after load, contractility
What is PVR
the after load of the right side of the heart
What is the normal CO?
4-8L/min
What is the normal CI?
2.4-4.0L/min
How is CI measured?
CO/BSA
What is stroke volume?
volume of blood pumped with each heartbeat (60-70mL per contraction)
Which heart rhythms will influence CO?
Tachycardia, Afib, Bradycardia, Asystole, and Vtach
How will Afib affect CO?
CO decrease by 30% followed by hypotension
How will Vtach affect CO?
won’t allow ventricles to fill, decrease CO
What is the first thing that needs to be done if Vtach or Afib is seen in terms of CO?
take BP
What are 4 things that affect preload?
venous return, total blood volume, atrial kick, and stiffness/thickness of ventricular wall
(volume and compliance)
What do alpha receptors do? and beta?
alpha constricts and beta dilates
4 factors that affect afterload
aortic impedance, blood viscosity, blood volume, vascular tone
What is SVR?
the afterload of the left side of the heart
