Hemodynamics Flashcards
The study of blood moving through the circulatory system describes
Hemodynamics
Blood flow depends on what 2 things
1) pressure gradient
2) resistance
How are pressure gradient and flow related
A) inverse
B) direct
B) direct
How are resistance and flow related
A) inverse
B) direct
A) inverse
The driving force behind flow is called
Pressure gradient
During systole which ventricle contracts
Left
What is another name for pressure energy
Potential
What type of energy is created by the pumping action of the heart
Pressure
What type of energy is energy of something already in motion
Kinetic
What is another name for gravitational energy
Hydrostatic
What type of energy is the weight of column of blood
Hydrostatic
Name 4 things resistance is determined by
1) vessel size length and diameter
2) thickness of blood
3) elasticity of walls
4) tortuous vessels
What changes the biggest effect of resistance of occur
Change in vessel diameter or radius
What law describes the relationship of resistance, pressure gradient and flow
A) poiseuille law
B) Bernoulli
A) poiseuille law
How are diameter and flow related
Directly
How are diameter and resistance related
Inversely
How is flow related to length and viscosity
Inversely
1) smaller radius
2) higher resistance
3) less volume
4) less diastole
All describe
Vasoconstricted
1) larger radius
2) less resistance
3) more volume
4) more diastole
All describe
Vaso dilated
Name the 7 vessels that are high resistive
1) ECA
2) fasting SMA
3) infrarenal AO
4) peripheral arteries ( CFA, SFA, subclavain, brachial)
Name the 7 vessels that are low resistance
1) ICA
2) post prandial SMA
3) supra renal aorta
4) organ arteries( celiac, hepatic, splenic, and renal)
What kind of resistance has little or no diastolic flow shows flow reversal and does “stop and go”
High resistance
What type of resistance has more diastolic flow and has a constant forward flow that’s non stop
Low resistance
Cold, stress and smoking cause what to happen to vessels
A) vaso constrict
B) vaso dilate
A) vaso constrict
Heat, exercise, and stenosis/ distal ischemia cause what to happen to vessels
A) vaso constrict
B) vaso dilate
B) Vaso dilate
What effect describes the relationship of pressure and velocity when radius changes
Bernoulli effect
How are pressure and velocity related
Inverse
What effect is responsible for flow separations
Bernoulli effect
Name the 2 types of blood flow
1) laminar
2) turbulent
What type of flow moves in concentric streamlines or layers
Laminar
This type of blood flow is considered organzied
Laminar
What type of flow is seen by the quality of the spectral window
Laminar
The spectral window indicates what type of flow
Laminar
Name the 2 types of laminar flow
1) parabolic
2) plug
What is the most common type of flow
Parabolic
Parabolic flow has the highest velocities where in a vessel
In the center
Parabolic flow has the lowest velocities where in a vessel
Next to the the wall
What type of flow is found at the origin of vessels
Plug
What type of flow is abnormal and considered disorganized
Turbulent
What type of blood flow forms eddy currents
Turbulent
Turbulent blood flow is often seen where
Distal to a stenosis or tortuous vessels
The Reynolds number is considered critical at what value
Greater than 2000
What are the 2 main factors for the Reynolds number
1) radius
2) velocity
How are radius and velocity related
Direct
When does post stenotic turbulence occur
After stenosis when vessel diameter is larger
What does spectral broadening indicate
Turbulence
Hemodynamically significant means the stenosis has reached at least what % diameter reduction
50%
A 50% diameter= _____% area reduction
75%
_____ to a stenosis has a high resistance waveform or absent diastolic component
Proximal
______ a stenosis the PSV and EDV are elevated
At the stenosis
______ to a stenosis has turbulent flow patterns and and low resistance waveforms
Distal to a stenosis
Monophasic, continuous with rounded peak and slow upstroke describes
Tardus parvus
A tardus parvus waveform indicates the presence of what level of disease
A) proximal
B) distal
A) proximal
Proximal to a stenosis = ______ obstruction
Distal
Distal to a stenosis = ______ obstruction
Proximal
What increases to compensate for a reduction in vessel area?
a) Resistance
b) Volume
c) Pressure
d) Velocity
d) velocity
According to the Law of Conservation of Mass, when there is a reduction in vessel radius or area, the velocity must increase to maintain the volume
What describes a decrease in pressure in an area of higher flow speeds
a) reynolds number
b) nyquist limit
c) bernoulli effect
d) poiseuilles law
c) bernoulli effect
The bernoulli effect states that pressure and velocity are inversely related
Which of the following scenarios will most likely result in turbulent flow?
a) 5 mm vessel at 90cm/s
b) 2 mm vessel at 280cm/s
c) 1 mm vessel at 90cm/s
d) 5 mm vessel at 280cm/s
d) 5mm vessel at 280cm/s
According to reynolds number the radius and velocity are both directly related to the likelihood of the turbulent flow
What term best describes flow that moves in parallel streamlines inside a tube?
a) turbulent
b) plug
c) laminar
d) parabolic
c) laminar
What increases to compensate for a reduction in vessel area?
a) velocity
b) resistance
c) pressure
d) volume
a) velocity
What is the significance of a monophasic, continuous waveform with a slow upstroke?
a) distal arterial occlusion
b) proximal arterial obstruction
c) normal vasodilation response
d) proximal venous obstruction
b) proximal arterial obstruction
this describes the tardus parvus waveform contour. This means we have arterial disease proximally and the waveform is documented distal
According to Poiseuilles law, what will happen to flow if the pressure difference increases?
a) flow velocity will increase
b) flow becomes turbulent
c) flow velocity decreases
d) flow rate will increase
d) flow rate will increase
BOARD QUESTION!!!
What cardiac event coincides with normal arterial flow reversal?
a) aortic valve closure
b) maximum ventricular contraction
c) mitral valve closure
d) maximum ventricular relaxation
a) aortic valve closure
-late systolic aortic valve closure results in a dramatic increase in pressure energy. The moving blood hits the “wall” of high peripheral resistance resulting in diastolic flow reversal
What best describes high resistance as seen on a doppler waveform
a) Decreased peak systolic velocity
b) Decreased end diastolic velocity
c) Increased end diastolic velocity
d) Increased peak systolic velocity
b) Decreased end diastolic velocity
The resistance is seen by how much DIASTOLIC flow there is. More diastole means more volume and more volume means low resistance. The higher the resistance, the lower the volume flow and the lower the diastolic flow
Which of the following principles, effects, or laws apply to decreased pressure with increase flow speed?
a) Bernoulli effect
b) Poiseuille law
c) Reynolds law
d) Murphys law
a) Bernoulli effect
The highest pressure in the arterial system is found in what region or organ?
a) Posterior tibial arteries
b) Left ventricle of the heart
c) Abdominal aorta
d) Internal carotid artery
b) Left ventricle of the heart
What is the most significant factor affecting diastolic blood flow in the lower extremities?
a) cardiac output
b) Systemic blood pressure
c) Vasodilation in the capillary bed
d) Vasoconstriction/dilation in the arterioles
d) Vasoconstriction/dilation in the arterioles
