Duplex/color Flow Imaging (UE) Flashcards
Duplex/color flow imaging can be used for many reasons such as localizing a stenosis/occlusion, determining the presence of an aneurysm, and two more reasons….
- Post-op study: hemodialysis access or arterial bypass graft
- detect AVF’s
When scanning a hemodialysis access graft, it may be difficult to adequately evaluate outflow vein due to ?
Increased collateral development
In duplex/color flow imaging of the UE, what is the “pledge position”
Patient positioning of the arm at a 45 degree angle from the body and externally rotated
Duplex scanning is a combination of these two things
Real-time B-mode imaging (brightness/gray scale evaluation) AND Doppler spectral analysis
The SAMPLE SIZE for acquiring pulsed Doppler is ___mm, and can increase if needed
1-1.5mm
T/F
It is UNCOMMON for arteries in the UE to become stenotic
TRUE
Referring to hemodialysis access scans, what is a THRILL
A thrill is a vibration that a dialysis access can produce (or stenotic area)
Put the following technique for evaluating a dialysis access graft in order from first to last step:
- observe for aneurysm, puncture sites, peri-graft fluid
- continue through body of graft looking for tears, fluid leaks, aneurysms
- evaluate outflow vein
- evaluate arterial anastomosis
- evaluate inflow artery
- observe for flow changes and/or turbulence
- evaluate venous anastomosis
- evaluate inflow artery
- evaluate arterial anastomosis
- continue through body of graft looking for tears, fluid leaks, aneurysms
- observe for aneurysm, puncture sites, peri-graft fluid
- observe for flow changes and/or turbulence
- evaluate venous anastomosis
- evaluate outflow vein
Name the 3 steps for a dialysis access FISTULA (e.g. Brescia-Cimino)
- Inflow artery
- Anastomosis
- Outflow vein
What is the typical diameter for a fistula
4 or 5 mm
With dialysis access, what is the Brescia-Cimino
It is the involvement of the cephalic vein and the brachial artery
Name two types of dialysis accesses used
Brescia-Cimino
Straight, looped synthetic graft
T/F
Currently, no criteria for classifying stenosis disease
TRUE
When interpreting an occlusion, we can look for this proverbial finding that is found proximal to an occlusion
A “thump”
A dilation of the vessel from degeneration and/or weakening of the wall is a/n…
Aneurysm
An ulnar artery aneurysm can form in response to using the palm as a hammer, this is called
Hypothenar hammer syndrome
A subclavian aneurysm is often associated with _____ to the digits
Embolization to the digits
Hemodialysis accesses can have variable PSV and EDV depending on the type of access, however, normally both are _____
Both are normally ELEVATED (e.g. PSV > 150cm/sec)
*increased pressure gradient difference
A low PSV obtained in an access graft could indicate what
Arterial inflow problems
- rounded waveform prox. To the problem
Why are follow up studies important for hemodialysis access interpretation
B/C there is no standardized velocity criteria currently, therefore, comparison of prior studies is helpful for interpretation
If volume flow is calculated in an exam, what is it labeled
Measured in mL/min
Due to initial hyperplasia or elevated arterial pressure, what is the site that is MOST COMMON for a stenosis with a hemodialysis access
(2)
The venous anastomosis
And
Outflow vein
One hemodynamic complication is the large blood volumes in the venous circulation that can increase venous return resulting in?
Congestive heart failure
more with a neck access
A hemodynamic complication when the distal arterial blood flow is reversed into the venous circulation and can cause hand pain on exertion, pallor and coolness of the skin distal to the shunt (arterial flow never gets to fingers)
Steal syndrome
*to compare, check index finger on opposite hand
To assess for possible “steal” we can use PPG to evaluate flow in atleast 2 digits (one at a time), then applying manual pressure to dialysis access and RETAKE digit PPG tracings and/or pressures… How would this show if there is steal or no steal
If flow IMPROVES = there is a steal
If flow STAYS THE SAME = most likely not a steal
