Session 28. Central Lines - Ultrasound Flashcards
frequency of wave
number of oscillations per second
pulse echo principle
higher energy excited crystals in transducer to vibrate
(piezo electric effect)
virbations emit
high frequency sound waves
piezo electric crystals
transmit ultrasound wave
receive reflected back ultrasound waves
ultrasound gel
improves image
ultrasound waves are ______ transmitted thorough air/liquid
poorly
liquids
anechoic (black)
low reflection
dense structure
hyperechoic (white)
high reflection
isoechoic
structures that exhibit the same brightness as its surrounding structures
acoustic shadowing
hyperechoic structure not allowing any waves to pass so structure behind appears anechoic
clean shadow
bone
dirty shadow
gasses
dirty shadow means the image is
blurry
acoustic shadowing is depended on
density of hyperechoic structure
acoustic window
when viewing anechoic structure (fluid filled), structures deep to them are enhanced secondary to wave progression through the fluid
ultrasound indications
vascular access
nerve blocks
diagnosi
ultrasound contraindications
none
practiioner lack of training could cause misdiagnosis
high frequency probe
shallow penetration
great resolution
types of high freq probes
linear/vascular
intracavity
low freq prob
higher depth of penetration
lower resolution
types of low freq probes
curvilinear
phased array
linear probe
shallow structure
vessel cannulation
most common probe
linear
curve linear probe
deep structures
nerve blocks (TAP)
diagnoses
2nd most common probe
curve linear
intracavity probe
OBGYN
colorectal
phased array probe
deepest viewing
diagnosis only
resolution
image clarity
how clearly you can differentiate 2 structure
axial resolution
ability to discern 2 separate objects that are longitudinally adjacent to each other
easy to change
lateral resolution
ability to discern 2 separate objects that are adjacent to each other
cannot change
which resolution can you not change
lateral
gain
overall brightness of image
amplitude of signal
turning up gain
image brighter
more evident artifacts
turning down gain
image darker
what will you adjust for every pt
gain
why do you adjust gain
each pt has a different body habitus w/different tissue density, volume status, etc
doppler/color flow
characterizes flow of fluid
inferred by frequency changes
moving towards probe
frequency increasing
red
moving away from probe
frequency decreasing
blue
Fd (doppler freq shift equation)
Fd = Ft-Fr
Fd= 2Ft(V/c)Cos(theta)
depth
adjusts frequency
to see deeper you need _____ frequency
lower frequency
lower frequency _____ resolution
decreases resolution
what depth should you start with
depth + 1
time gain compensation
modifying the gain in particular fields of depth
probe notch
corresponds to indicator in screen to ensure consistent laterality
needle will look like ______ on ultrasound
hyperechoic line
where should you aim your needle insertion when using ultratound
1 cm behind probe at the center line
how can you differentiate artery and vein on ultrasound
vein will collapse w/pressure
artery will pulse
what do nerves look like under ultrasound
hyperechoic
bundle of grapes
what does a clot look like under ultrasound
hyperechoic region inside vein
