Duplex/CDI UE Flashcards
capabilities
localize stenosis / occlusion
localize aneurysm
post-op f/u - BPG , AVF, STENT
limitations (1)
limitations specific to AVF (2)
- cast/ IVsite
- graft angulation
- increased collateral formation causes difficulty evaluating the outflow vein
Pt. position
supine
pledge position, arm rotated out 45 degrees
Physical principles:
what is ideal sample size for Doppler analysis
1-1.5 mm
Physical principles:
with CDI frequency of signal is assigned a ____ or _____ of color
hue or shade of color
Physical principles:
what frequency probe is used
5-7 MHz linear array
it is uncommon for UE arteries to become ____. Most common artery in UE eval to have this disease process is
stenosed
subclavian artery
most common indication for UE exam
evaluation of dialysis access grafts
dyalysis is accomplished by
communication of artery and vein,
creating high blood volume situation
a thrill is
vibration
it is palpated
a bruit is
noise
it is auscultated
what hemodialysis access condition commonly causes a thrill
stenosis
steps for eval of dialysis access graft :
7
inflow artery
arterial anastomosis
body of graft
observe aneurysm, puncture sites, peri-
graft fluid
use color to observe flow changes/ turbulence
venous anastomosis
outflow vein
Brescia-Cimino is connection of what typically
assessment sites include
cephalic vein and radial artery
inflow artery
anastomosis
outflow vein
radial artery Doppler
Autogenous Fistula is
any artery attached to any adjacent vein that includes native vessels
eg- Brescia Cimino
identify two types of synthetic dialysis grafts
loop graft _ loop connection between artery and vein
straight graft - runs through arm connects artery and vein
Thrill is usually a sign of stenosis, but in dialysis graft it is a ____ finding
normal
because of the high volume of blood flowing through the anastamosis
what are you r/o in dialysis access
annnnnd how do you accomplish that
steal syndrome
plaque
stenosis
patient anastamosis, inflow and outflow veins
run Doppler through
normal AVF
normal PSV varries, waveform us usually multiphasic
parameters for > 50% stenosis
stenosis PSV : Prox vessel PSV
2:1 ratio
flow acceleration post stenosis turbulance
complete occlusion is proved by
no detection of CDI or Doppler
B-mode shows narrowing
“thump” prox to occlusion
dampened WF distal to occlusion when collateral flow is present
Aneurysm is proved by
dilation of the vessel >1.5 x size of adjacent segment
what is the most common aneurysm site
subclavian artery
usually associated with distal embolization of the digits
ulnar artery aneurysm is called
Hypothenar Hammer Syndrome
occupational injury repetitive use
eg jack hammer
causes aneurysm or thrombosis of ulnar artery (usually at palmar arch)
interpretation of Hemodialysis Access
normal waveform
disturbed , low resistance , high velocity flow
eg PSV > 150 cm/sec
comparison to previous studies is key
PHASE NOT USED TO DESCRIBE DIALYSIS AVF -either high resistant or low resistance
interpretation of Hemodialysis Access
most common site for stenosis is
outflow vein
due to hyperplasia or elevated arterial pressure
interpretation of Hemodialysis Access
low PSV in access graft can indicate ______ problems
inflow
will look like dampened waveform will indicate problem in the inflow artery
other hemodynamic complications of AVF
2
CHF
steal syndrome
how can AVF cause CHF
large blood vol in venous circulation can increase venous return
= CHF
what is steal syndrome
distal arterial blood flow is reversed (shunted) into venous flow
creates pallor and coolness of the skin distal to the shunt and eventually ischemia
explain procedure for eval of steal syndrome
with dialysis access open and functioning use PPG to eval flow to at least 2 digits one at a time
manually compress dialysis access and retake digit PPG tracings or Pa
if flow improves after compressing the AVF than it is positive or negative for steal syndrome
positive
There will be retrograde flow in outflow arterial vessel below venous anastamosis
if flow stays the same during compression than another cause of ischemia should be investigated
