1
Q
Define hemodynamics.
A
The study of blood moving through the circulatory system
2
Q
Define the 4 pumps that move blood within the body.
A
- Heart pump: contractions push blood into the aorta and lungs
- Aortic pump: aorta expands to accept bolus of blood and recoils, pushing blood forward in a pressure wave
- Calf muscle pump: squeezing of calf muscle propels venous blood towards heart
- Respiratory pump: changes in thoracic and abdominal pressure sucks venous blood back towards the heart
3
Q
What is flow volume rate in relation to hemodynamics?
A
The amount of RBCs that move through a vessel in a specific time period
4
Q
What is velocity in relation to hemodynamics?
A
How fast blood moves from one location to another, measured in cm/s
5
Q
What are the 3 forms of flow? What are their influencing factors?
A
- Pulsatile: heart muscle contractions (associated with arterial circulation)
- Phasic: respiration (associated with venous circulation)
- Steady: normal (MPV + proximal IVC) or abnormal (DVTs)
6
Q
What kind of flow occurs when blood moves with variable velocity?
A
Pulsatile AND phasic
7
Q
Are there several pulse points around the body?
A
Yes; we can measure pulse at various locations
8
Q
What kind of flow is dependent on the respiratory cycle?
A
Phasic
9
Q
Can you eliminate phasic flow? Pulsatile flow?
A
Yes to phasic; you can hold a breath and flow would halt
No to pulsatile; cannot stop heart from beating yourself
10
Q
What kind of flow occurs when blood moves with the same velocity?
A
Steady
11
Q
Where would we expect pulsatile, phasic, and steady flow in relation to baseline?
A
Pulsatile AND steady flow = above baseline
Phasic = below baseline
12
Q
On a waveform, how would you expect a vein to react upon exhalation and inhalation?
A
The absence of a waveform would indicate the patient inhaled, while the presence of a waveform indicates exhalation
13
Q
Define laminar vs turbulent flow.
A
Laminar:
- streamlines aligned & parallel
- normal flow pattern
- two types:
1. plug flow (same velocity and same direction i.e. AO)
2. parabolic flow (bullet shaped, slower along walls from friction)
Turbulent:
- streamlines obliterated
- direction + velocity disrupted
- eddy currents/vortexes form
- abnormal flow pattern
14
Q
What is turbulent flow most likely associated with?
A
Stenosis
15
Q
Where is turbulent flow found in stenosis? What is this called?
A
Downstream from the affected area; Post-stenotic turbulence
16
Q
Is turbulent flow quiet or considerably present?
A
You can hear it with a stethoscope usually (murmur, bruit)
17
Q
In order for fluid to flow from one place to another, what has to be present?
A
An energy or pressure gradient (interchangeable)
18
Q
What are the 3 forms of energy?
A
- Kinetic: object in motion
- Pressure: stored energy/has potential to move AKA potential energy
- Gravitational: stored potential associated with an elevated object
19
Q
What are the 3 reasons for energy loss?
A
- Viscosity: thickness of fluid (depends on % RBCs)
- Friction: blood cells rub against arterial wall and slow down
- Inertia: when there is a change in motion of the blood/flow direction
20
Q
When the left ventricle of the heart contracts, blood immediately….
A
begins to lose energy
21
Q
The flow of blood _________ at the site of stenosis.
A
Increases
22
Q
The flow of blood _________ AFTER the site of stenosis.
A
Decreases
23
Q
What is the relationship of pressure and flow?
A
Pressure gradient = Flow X Resistance
Pressure gradient increases when flow increases or resistance increases.
Flow increases when pressure gradient increases or resistance decreases.
24
Q
Compare Ohm’s Law to blood circulation.
A
Ohm’s Law states voltage = current X resistance
Our system is similar to that of an electrical circuit
25
Which of the following characteristics of blood do diabetics, smokers, hypertensives, post-menopausal women, and most middle age men, all have in common?
A. elevated cholesterol
B. missing clotting factor
C. low hematocrit
D. high viscosity
D. high viscosity
26
What is the stated difference between blood of men and the blood of pre-menopausal women?
a. men have thinner blood than women
b. pre-menopausal women have a lower blood viscosity than men
c. post-menopausal women have a lower blood viscosity than men
d. men have higher blood viscosity than post-menopausal women
b. pre-menopausal women have a lower blood viscosity than men
27
Diabetes results in _______ blood viscosity.
Higher
28
In order for fluid to flow from one place to another, there must be a...
Pressure gradient/difference in pressure
29
If the concept is represented by the following:
Pressure Gradient = flow x resistance
What happens to the pressure gradient if resistance increases?
The pressure gradient also increases
30
Differentiate right-sided circulation and left-sided circulation in the heart.
Right - lungs
Left- systemic
31
Which exchanges does circulating blood allow for?
Blood gases, nutrients, and waste products
32
What are the semilunar valves vs atrioventricular valves?
Semilunar - pulmonic and aortic
AV - tricuspid and mitral
33
Where is myocardium the thickest?
The ventricles (specifically the left)
34
For blood to flow, what are the 3 requirements?
1. Electrical conduction that stimulates the myocardium to contract
2. Contraction of the heart muscle that causes pressure to increase on one side of the heart valves
3. Pressure gradient for the valve to open
35
What is considered the pacemaker of the heart?
SA node
36
There is a 100 msec delay at the AV node. What controls this delay?
The SA node
37
Define each portion of an EKG/ECG.
P wave- diastole / atrial contraction or depolarization
QRS complex- systole / ventricular contraction or depolarization
T wave- ventricular repolarization
38
List the layers of the heart from outer to innermost.
Epicardium
Myocardium
Endocardium
39
What is M Mode and what is it used for? Why?
Motion mode; echos + fetal echos; gentler than color+pulsed wave Doppler
40
During diastole aka the ventricular filling phase, which valves are opened and closed?
Aortic and pulmonic are closed, tricuspid and mitral open
41
During systole, which valves are opened and closed?
Aortic and pulmonic are open, tricuspid and mitral closed
42
How much of a pressure difference do the chambers of the heart/valves exceed?
Over 1 degree systolic OR diastolic
43
Define pre-load vs after-load.
Preload- what happens in venous circulation
Afterload- what happens in arterial circulation
44
Define the sulci in relation to the coronary arteries.
External grooves of the heart that contain the coronary vessels, supplying blood to the heart itself
45
Are the coronary vessel embedded in a layer of fat?
Yes, for protection
46
What supplies blood to the arterial walls?
Vasa vasorum
47
What continues to move arterial blood?
Recoil
48
What are the direct branches off the aortic arch?
Brachiocephalic/innominate artery, Left CCA, Left subclavian
49
What does the brachiocephalic/innominate artery branch into?
Rt Subclavian and Rt CCA
50
Which vessel(s) brings a constant supply of blood and oxygen to the brain and eyes?
Internal carotid arteries
51
Which vessel branches off the extra-cranial carotid arteries can have its branches insonated while scanning the main branch?
External carotid arteries
52
The vessels that join to create the Basilar Artery which supplies the circle of Willis are called the...
Vertebral arteries
53
The vertebral arteries branch from the:
Subclavian arteries
54
Which of the following segments of the lower extremity arterial system is considered the inflow?
a. aorto-iliac
b. femoro-popliteal
c. tibio-peroneal
a. aorto-iliac
55
Which of the following segments of the lower extremity arterial system is considered the outflow?
a. aorto-iliac
b. femoro-popliteal
c. tibio-peroneal
b. femoro-popliteal
56
Which of the following segments of the lower extremity arterial system is considered the runoff?
a. aorto-iliac
b. femoro-popliteal
c. tibio-peroneal
c. tibio-peroneal
57
If your patient were experiencing pain in the calf muscle, in which of the three segments of the lower extremities would you expect to find disease?
Both the out-flow segment and the run-off segment, although most commonly the out-flow segment
58
Which vessel(s) bring a supply of blood to the scalp and face?
External carotid arteries
59
What is the percentage of blood that gets divided among the ICA and ECA?
ICA 80%, ECA 20%
60
Define bolus.
A large quantity of something administered all at once
61
What kind of organs are supplied with high resistance vs low resistance waveforms?
High- not vital organs (face, scalp, extremities)
Low- vital organs (brain, kidneys)
62
Blood flow is ______ throughout the cardiac cycle of the ICA.
Continuous and forward in systole an diastole
63
Blood flow is ______ throughout the cardiac cycle of the ECA.
Forward during systole and low/reversed during diastole
64
What does the dicrotic notch signify on waveform?
Closure of the semilunar vales (end of systole)
65
The highest blood flow velocity exists at...
Peak systole
66
The lowest blood flow velocity exists at...
End diastole
67
When do we observe window filling/spectral broadening?
Turbulent flow or with improper sample gate size (which is spirious)
68
What kind of waveform does the CCA exhibit?
Sharp systolic upstroke followed my constant forward diastolic flow
69
How does turbulent flow appear with color Doppler?
Mixed/aliased
70
Is reversal of flow normal at the site where the CCA bifurcates?
Yes
71
What does power Doppler show?
The presence or absence of flow (it's more sensitive)
72
High scale = _____ flow, low scale = _____ flow
high; low
73
What is thump flow and what causes it?
Vibration of arterial walls due to elastic recoil
74
Explain a normal arterial waveform.
Triphasic; forward at onset of systole, small reversal, then forward diastole due to elastic recoil
75
The ___ the peripheral resistance, the easier it is for blood to perfuse tissues.
Lower
76
The ___ the peripheral resistance, the harder it is for blood to perfuse tissues.
Higher
77
Does vessel size affect the resistance of blood flow? Why?
Yes; a smaller diameter means blood will be interacting more with the arterial wall than that of a wide-diameter artery
78
Describe the differences in normal waveform appearances of the lower extremity arteries in relation to age and gender.
As we age, arterial walls stiffen and therefore peak systolic velocity will likely decrease. Additionally, women will exhibit lower peak diastolic velocities compared to men in the same age group.
79
T or F: The descending aorta provides blood to the upper extremities.
FALSE
80
What best describes the term "end-diastole"?
the lowest velocity, just prior to the upstroke associated with the next cardiac cycle
81
What characteristics do the CCA and ICA have in common?
Constant forward flow in disatole
82
Color Doppler can provide all of the following information about blood flow EXCEPT:
a. absence or presence of flow
b. direction of flow
c. mean velocities of flow
d. smooth or turbulence of flow
e. quantifiable flow velocity
e. quantifiable flow velocity
83
When scanning the cerebrovascular system (carotid arteries and vertebral arteries), the sonographer is ready to demonstrate flow in the vertebral arteries. What combination of ultrasound system adjustments should he/she make to properly visualize the vertebral arteries?
a. increase velocity scale and increase depth
b. decrease velocity scale and increase depth
c. decrease velocity scale and decrease depth
d. increase velocity scale and decrease depth
b. decrease velocity scale and increase depth
84
The term that best describes the normal waveform pattern associated with the peripheral arterial system of the legs is...
Triphasic
85
How does an increase in peripheral resistance to blood flow affect blood pressure?
It will also increase
86
To which circulatory system does the concept of "peripheral resistance" apply?
Only the peripheral vascular system the brings blood to non-vital organs
87
When the patient clenches and releases his fist, the waveform pattern of blood flow in his upper extremity changes. Why?
The fist clenching increases peripheral resistance so the waveform becomes triphasic, but when the fist is released blood flow freely and continuously so it becomes a low resistance pattern
88
Arteries need to withstand __________, whereas veins need to withstand ______.
High pressure; large volume
89
How does the calf muscle pump work?
Activation of the soleus (calf) muscles where they contract + squeeze the popliteal + tibial veins, forcing blood to move upwards
90
As the diaphragm contracts, how does it move and affect pressure in the body?
Moves down, increasing abdominal pressure and decreasing thoracic pressure
91
As the diaphragm relaxes, how does it move and affect pressure in the body?
Moves upwards, increasing thoracic pressure and decreasing abdominal pressure
92
Venous circulation is considered ________ flow.
Retrograde
93
For standing individuals, how is pressure related to above the level of the heart and below it?
Above the heart is negative, below the heart is positive
94
What is the hydrostatic pressure for someone who is supine?
0 mmHg
95
What is hydrostatic pressure?
Pressure on fluid from gravity
96
At which point of the respiratory cycle does the diaphragm contract vs relax?
Contract - inhalation/inspiration
Relax- exhalation/expiration
97
What determines the shape of a vein and its blood volume?
Transmural pressure (pressure acting on the venous walls to expand the vein)
98
As transmural pressure increases, what are the 3 different appearances on the veins?
Dumbbell-shaped --> oval --> circle
99
What are 2 conditions that can lead to an increase in venous pressure?
Venous hypertension and congestive heart failure (right sided heart failure)
100
What kind of waveform does venous hypertension exhibit?
Pulsatile
101
Define regurgitation vs reflux.
Regurgitation = arterial backflow, reflux = venous backflow
102
If plaque is present in the CCA, what can we do to pick up blood flow?
Decrease our scale to make it more sensitive
103
As the calf muscle is contracting, what corresponding action is occurring with the valves?
They're opening
104
As the calf muscle is relaxing, what corresponding action is occurring with the valves?
They're closing
105
The diaphragm is a large, ____ muscle.
Flat/domed
106
As the diaphragm moves downward, the size of the thoracic cavity
Increases
107
As abdominal pressures increase, blood flow returning to the heart through the veins of the lower extremities is impeded by
Increased pressure
108
Identify the three types of veins found within the lower extremity and name the type that is typically paired with an artery, the type that is found in subcutaneous tissue and the type that connects or communicates with the other two.
1. Superficial veins: found in subcutaneous tissue
2. Deep veins: travels with an associated artery deep inside the muscle
3. Perforator veins: connect the superficial and deep veins to one another
109
Compare the average sizes of the deep veins and the superficial veins.
Deep veins are usually larger in diameter compared to superficial veins. The measurements of the lower extremity deep veins are as follows: common femoral vein measures between 1.2-1.9cm, superficial femoral vein between 0.9-1.0 cm, popliteal vein 0.9-1.5cm, and tibial veins around 0.5cm.
Superficial veins: great saphenous vein measures between 0.4-0.6mm in the thigh, 0.2-0.3cm in the calf, and the small saphenous vein measures between 0.4-0.7cm
110
Describe the blood flow in the lower extremity veins.
Spontaneous and phasic with respiration, ceasing with inspiration and augmenting with expiration.
111
Explain why taking a patient's blood pressure at the brachial artery of the upper main may be the best location.
The most accurate measurement is the one at the level of the heart.
112
At what anatomical location on the body will the patient's measured pressure be less than his actual circulatory pressure?
At the level of the head
113
As veins increase in size to accommodate the increase in blood volume, what happens to resistance to flow?
Decreases, which increases flow back to the heart
114
Movement of blood in the lower extremity venous system is influenced mainly by all of the pumps EXCEPT:
Aortic pump
115
Name and define the factors which affect cardiac output.
CO = heart rate X stroke volume
HR = # of ventricular contractions in 1 min
SV = the amount of blood pumped out from each of the ventricles
116
What affects stroke volume directly?
Contractibility, pre-load, and after-load
117
Pre load is also describes as the volume in the....
ventricles at the end of diastole
118
What are 3 pathologies related to pre-load circulation?
Renal cell carcinoma/tumor invasion of the IVC
Blood clot (downstream turbulent flow)
Leaky valve in peripheral veins (blood doesn't return)
119
What are 2 pathologies related to after-load circulation?
Hypertension (walls or arteries harden, stiffen, and cannot expand or contract leading to poor circulation)
Valvular stenosis (harder for blood to flow out of the heart)
120
How else is after-load defined in relation to pressure gradient?
It is the pressure requiredd to open the semilunar valves (Aortic and pulmonic)
121
If the heart muscle dies, what happens to the heart wall?
It thins
122
If the heart wall thins, what is it unable to support?
The force of the pressure from the chambers
123
If the heart is unable to withstand the force being exerted by the chambers, what condition can this lead to?
Ventricular aneurysm, which creates a swishing effect of blood flow therefore turbulent flow
124
The mitral valve separates the... from the ...
left atrium from the left ventricle
125
When the sonographer assesses a valve for competency, one technique that is used is called
Color flow Doppler
126
How might an MI affect the pumping motion of the heart?
Lack of efficient pumping
127
How might an MI affect the wall motion of the heart?
Cannot expand and contract as it once did
128
How does an occlusion of the coronary arteries at different location affect patient outcomes?
Pulmonary vs systemic
129
If there is severe valvular regurgitation, what happens to blood circulation?
Blood will pool in the heart and will not be able to be pumped into circulation
130
If CHF worsens and becomes severe, what happens?
The IVC and hepatic veins will begin to back up with fluid
131
Explain how a tumor within the heart can impact hemodynamic flow patterns.
Even if it's a benign myxoma, there will be narrowing of the chambers or the tumor can situate on top/near a valve keeping it open or closed constantly
132
What is endocarditis?
Bacterial infection of the inner lining of the heart
133
What happens if endocarditis progresses?
Vegetations may form on the valves, which may create a stenosis and impact blood flow through the heart and ultimately the body
134
What is the most common cause for endocarditis?
Poor oral hygiene/bacteria entering bloody gums
135
What are some indications for an echo?
Chest pain, SOB, fatigue, weakness, lightheadedness
136
What is dilated cardiomyopathy?
The myocardium weakens and the chamber dilates, which leads to ineffective pumping of the blood and slow blood flow (risk of blood clot)
137
A bulge in the left ventricle along with the thinning of necrotic tissue of the infarcted wall and the high pressure in the ventricle during ejection may cause...
Rupture
138
Which type of lipoprotein is responsible for the development of atherosclerosis?
Low density lipoprotein (LDL)
139
Macrophages that have ingested the oxidized LDL's are called:
Foam cells
140
What does the presence of foam cells trigger?
The recruitment or more WBCs to repair the arterial wall, leaving a larger deposit on the wall
141
What is considered high cholesterol?
200< mg/dL
142
What is the progression of atherosclerosis?
Arteries in legs narrow/clog with plaque --> PAD --> arteries harden and continue to narrow over time = atherosclerosis
143
When arteries inside the heart are hardened or narrowed, it is called
Coronary Artery Disease (CAD)
144
Does PAD only affect the legs?
No, it can affect other parts of the body too
145
Patients with PAED are at high risk for
Heart attack or stroke
146
Define intermittent claudication.
Pain to the legs when walking
147
Peripheral Arterial Disease affects...
10 million americans
148
Treatment of PAD includes all of the following EXCEPT:
a. smoking cessation
b. controlling high blood pressure
c. leg pain treatment
d. controlling diabetes
c. leg pain treatment
149
The buildup of plaque causes the arteries to harden and narrow. This is known as:
Atherosclerosis
150
The most severe form of PAD includes:
ulceration and sores on the legs and feet that do not heal easily
151
An ABI is calculated by..
ABI = highest ankle pressure divided by the highest brachial pressure
152
An Ankle Brachial Index below .99 shows...
Decreased blood flow
152
A normal Ankle Brachial Index is...
1.0
153
As the severity of the disease increases, the number related to the Ankle Brachial Index:
Decreases
154
Which of the following is NOT part of the patient prep prior to an ABI exam?
a. no smoking for at least 2 hours prior to the exam
b. the patient must walk around for 15 to 20 minutes
c. the patient should rest in the supine position
d. the patient should be keep warm
b. the patient must walk around for 15 to 20 minutes
155
When obtaining the ABI, the sonographer should inflate the cuff no more than ___ above the last sound heard.
30mmHg
156
If a difference of greater than 20mmHg occurs between the arms, what is usually suspected?
arterial (generally subclavian) obstruction
157
What are the 4 categories of ABIs?
normal, claudication, rest pain, and tissue loss
158
A low ABI score also indicates the patient is at risk for...
Other forms of arterial disease, including CAD
159
How is an ABI performed?
Place blood Pressure cuffs on the upper arms bilaterally and at the ankles bilaterally just above the medial malleolus.
Obtain an audible arterial Doppler signal. The Doppler pen should be toward flow with a 45 - 60 degree angle to obtain the best signal.
Once a strong signal is obtained, inflate the cuff until the signal is no longer heard, then continue to inflate cuff another 20-30mmHg. Keep the probe steady on the vessel.
Deflate the cuff slowly until the audible Doppler signal returns. Note the pressure at which the signal is heard as this is the systolic pressure you will record. Apply the same procedure at the other sites and calculate the ABI. Remember to use the highest brachial pressure for calculating each leg into the ABI.
160
In order to optimize your ABI examination, the sonographer should use what to obtaint the audible spectral Doppler?
Small sample volume and 60-degree angle
161
The pressure applied to the skin by the ultrasound transducer must maintain good contact, but can NOT be excessive or it may...
Obliterate the arterial Doppler signal
162
A low ABI means the blood pressure in the legs is lower than that of the arms, indicating that PAD is...
restricting blood flow to the legs.
163
Differentiate homogeneous vs. heterogeneous plaques and explain how echogenicities are related to different types of pathology.
Homogenous plaques are generally soft and newer, making it difficult to pick up on ultrasound at times. They appear smooth and consistent in texture, usually staying put where it is located.
Heterogenous plaques are usually hardened and indicate a long-term presence within the vessel, increasing the likelihood of an embolism forming and breaking away. This kind of plaque appears with mixed echogenicity. The more heterogenous the plaque, the more dangerous it is in terms of a blood clot breaking off.
164
What sizes are too large and too small of a sample gate? What is the normal sample volume box size usually kept between?
>3.0mm too large, <1.5mm too small
2-3mm
165
Fatty Plaques can develop a hard fibrous calcific cap that is at risk of ...
Rupture
166
Spectral broadening can happen with
Stenosis
167
A patient with pain in the legs at rest would demonstrate an ABI of less than..
0.4
168
The sample volume box placed on the curve of a tortuous vessel may lead to an _______estimation of the true velocity
over
169
What are the 5 signs and symptoms of PAD?
the 5 P's: Pain, pulselessness, pallor, paresis, paresthesia
170
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