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What is the main arterial testing questions? (5)
- Questions for claudication.
- Where is the pain?
- How far can you walk?
- How long does the pain take before it goes away?
- Any surgeries? Stents or grafts?
What is the reason for claudication?
the blood can not make it to the tissues causing ischemic.
What will happen when someone is laying down?
The skin is usually what color?
1. blood vessels will dilate to try to get blood to lower tissues.
2. the skin will be pallor (white).
What is happening when someone first swings their legs off the side of the bed?
1. the blood vessels are still dilated so the blood will rush to the feet.
2. causing the skin to turn rubor (red)
What 3 things can cause a thrill or vibration?
- 1. fistula
- 2. post-stenotic turbulence
- 3. patent dialysis access site
What are Bruits?
are noises heard as a result of turbulent flow.
When may a bruit disappear?
if the stenosis is greater than 90%
What is CW Doppler? (2)
What are two examples of CW Doppler?
- 1. No image
- 2. Uses 2 crystals
- 1. pencil probe
- 2. handheld BP
What does a strip chart recorder do? (4)
- 1. Analog waveforms are generated.
- 2. Use a zero-crossing detector
- 3. Estimation of the mean frequency
- 4. Most equipment does self-calibration
What are 4 drawbacks to strip chart recorders?
- 1. Noise
- 2. Less sensitivity
- 3. High velocities are underestimated.
- 4. Low velocities are overestimated.
What are 5 limitation to arterial non-imaging testing?
- 1. Patient's with casts or extensive bandages.
- 2. Waveforms may be affected by ambient temperatures.
- 3. Uncompensated (not under-control)
- 4. Unable to discriminate stenosis form occlusion.
- 5. Technically dependent test
What are two things a patient's position should be?
- 1. Supine with extremities at same level as the heart.
- 2. Patient's limbs are straight and relaxed.
What are 6 sonographer error when performing arterial segmental testing?
- 1. Improper probe position
- 2. Inadvertent probe motion
- 3. Incorrect angle of incidence. Aim for 45 degrees.
- 4. Inadequate amount of gel
- 5. Excessive pressure on the probe tip.
- 6. Insufficient period of rest before testing at least 15 minutes told you before, may see 10 minutes of rest in some labs.
What are 5 trouble shooting things a sonographer could do if having trouble with arterial segmental testing?
- 1. Recorder stylus not recording
- 2. Check proper test selection or probe
- 3. 60 cycle noise on tracing: decrease gain
- 4. Recording stylus stuck at lower portion of tracing: hit reset
- 5. Audible signal, but no tracing: check if on or in pause/freeze mode.
What do you do if a patient can not be exercised?
What should a sonographer do when excersing patient? (4)
- 1. maintain pre-exercised waveforms.
- 2. signals will be less resistive (continuous)
- 3. Use treadmill for 5 minutes
- 4. take pressures within 30 seconds-1 minute
Treadmill use for Excersing patient
2 mph at 12% grade
1.5 mph at 10% grade
What are 4 abnormal things about waveforms that you may see after excersing patient?
- 1. Slow upstoke
- 2. More rounded peak
- 3. Slow down stroke
- 4. No reversal component
What 2 things would an absent Doppler signal represent after excersing a patient?
1. Suggests occlusion or preocclusion (string sign)
2. Analog can't detect velocities less than 6 cm/sec.
What does Spectral Analysis use?
- 1. FFT
- 2. Tells us of all of the different velocities of RBC's at any given time.
- 3. Signal can be displayed over time.
- 4. Display different shades of gray signify blood flow.
What are on each of the spectral display axis?
x-axis: time of flow
y-axis: Doppler frequency in kHz or velocity in cm/sec or m/sec
z-axis: Amplitude of the returning shift gray scale
What are the components of normal spectral analysis?
Name 7 and Draw
- 1. Systole
- 2. Peak systole
- 3. Diastole
- 4. End diastole
- 5. Window
- 6. Envelope
- 7. Scintillations
What does Scintillations mean on spectral analysis?
Represent blood flow velocities.
What does spectral broadening mean?
What will be seen? (2)
What are 3 things that can cause this?
turbulent flow = RBC's going at many different velocities
Velocities and peak end diastolic velocity will increase
- 1. stenosis
- 2. tortuous vessels
- 3. dissection
A ____ diameter reduction = a ____ area reduction.
50% = 75%
What are three things that influence waveform shape?
- 1. HR
- 2. BP
- 3. Vasomotor changes
What is very helpful with waveform analysis when differentiating normal form diseased vessels?
Diastolic flow reversal
What is vasomotor changes?
causing the vessels to constrict or dilate.
What does waveform analysis requires an understanding of what 3 things?
- 1. phasicity
- 2. flow direction
- 3. peripheral resistance
What are the components of Triphasic waveforms?
- 1. Rapid upstroke
- 2. Sharp peak
- 3. Rapid downstroke
- 4. Flow reversal
- 5. Resumption of forward flow
What are the components of Biphasic waveforms?
- 1. Rapid upstroke
- 2. Sharp peak
- 3. Fairly rapid downstroke
- 4. Flow reversal
- 5. No resumption of forward flow
What are the components of Monophasic?
- 1. Slow upstroke
- 2. Rounded peak
- 3. Slow downstroke
- 4. No reversal
- 5. Non-pulsatile
What does monophasic waveforms suggests?
advanced arterial disease proximal to the point of Doppler interrogation.
When might happen to a signal if there is adequate collateral run-off?
pre-stenotic signal may be normal
What will you always have after an arterial stenosis?
What does PI stand for?
What is another name for PI?
What is PI used for?
Where is PI used for?
lower extremity and transcranial Doppler
Differentiate in flow from out flow disease
What are the average scale of PI in the legs?
- CFA = >= 5
- POPA = 8.0
- PTA = 12-16
PI increases going down the leg or from proximal to distal leg.
What does AT stand for?
What is AT used for?
What is a normal AT value?
What does an abnormal value suggests?
Differentiate inflow disease from outflow
< 133 m/sec
> 133 = significant iliac disease
What can cause a false-positive Acceleration Time?
technical error and poor CO
What does RI stand for?
What is another name for RI?
What is RI used on?
What is the normal RI value?
What is the abnormal RI value?
If RI = 1.0 probably have an what?
- Resistivity Index
- CCA waveforms as an indicator of the peripheral resistance, also kidneys
- Normal value = .75 or below
- Abnormal value = .75 or above
- If RI = 1 probably have an occlusion