Q2 Flashcards
Blood flow influenced by (3)
cardiac function
elasticity of walls
respiration
T/F the number of times the heart contracts per min is HR
true
laminar flow can be described as (3)
- fluid flows in parallel layers
- smooth flow pattern
- observed in normal vessels
T/F bernouli effect describes a drop in pressure ______ a hemodynamically significant stenosis
distal to
During inspiration all the following occurs (3)
- intra-abdo pressure increases
- venous valves in legs close
- blood flow in peripheral vessels reduced
NOT intrathoracic pressure increases
During expiration all the following occurs (3)
- intra-abdo pressure decreases
- pressure gradient
Valsalva maneuver is useful to diagnose
incompetent venous valves
Physiologically blood flow is principally determined by
BP and vascular resistance
t/f respiratory movements aid in moving venous blood towards heart
true
Facts about the muscular venous pump (3)
- muscular pump squeezes veins and propels blood forward
- calf/thigh muscles aid in propelling blood toward the heart
- there is enough of a pressure gradient to ensure venous return at
NOT TWO WAY VALVES
as a pressure wave propagates through an artery, which of the following arteries (systolic pressure and mean pressure)
systolic pressure increase
mean pressure decrease
Peripheral resistance controlled at which level of vasc system
arterioles
T/F The longer the vessel length, the greater the resistance encountered and greater the BP
True
A critical stenosis defined as narrowing of the arterial lumen resulting in a hemodynamically significant reduction in: (3)
Volume
Pressure
Flow
Characteristics of venous flow include all of the following (3)
phasicity
spontaneity
augmentation
NOT resistance
Which has the most profound effect on resistance to flow
viscosity
Polycythemia facts (3)
- condition of elevation hematocrit
- higher blood viscosity
- increases the work of the heart and can impair organ perfusion
Flow pattern in pt with normal vessels change during exercise
it will become lower resistant
T/F augmentation is a maneuver that aids in determining if a pt has an obstruction in a peripheral vein
True
The frequency of the transducer influences (3)
image resolution
usable image depth
doppler shift
NOT angle correct (answer)
using angle correct at 60 degrees is necessary for all the following to occur (3)
- reliability between scans
- accurate PSV measurements
- accurate ratio measurements
NOT measuring venous flow
T/F regarding spectrum analyzer, if angle correction is applied, the spectrum will not represent the range of velocity the sample volume
false
It WILLL represent the range of velocity
t/f colour doppler is not helpful in diagnosing stenotic zones
FALSE (question is “which of the following is not true regarding colour dop”)
t/f As the frequency increases, so does the resolution, but the depth of penetration decreases
True
to improve colour flow image, which is the LEAST useful (1)
use a straight box
t/f the PRF toggle should be used to decrease the colour velocity scale when colour aliasing is seen in a normal vessel
False
t/f the PRF toggle can be used to increase doppler velocity scale when aliasing occurs within a stenosis
true
cosine of an angle of insonation at 90 degrees is
0
spectral aliasing is caused by all of the following (3)
and except
- velocity scale too small
- baseline too high
- PRF set too low
EXCEPT - doppler gain too high
t/f the colour bar indicated the range of frequencies in a spectrum
true
an oversized colour box affects all of the following (3)
and except
decreases the resolution
decreases the colour fill-in of the vessels
decreases the frame rate
EXCEPT increases the frame rate
t/f using a venous setting while scanning the carotid arteries will affect the colour image quality due to a colour velocity scale that is set too high
false
colour “bleeding into the tissues” outside the vessel can be corrected by
decreasing the colour gain
advantages of using power doppler include all of the following (3)
and EXCEPT
- there is no aliasing
- there is angle independent
- distinguishes between pre-occlusive from occlusive lesions
EXCEPT increase sensitivity to high velocity states
