1.6 Hemodialysis Grafts & AV fistulas Flashcards
Significant stenosis appearance on spectral (4)
- decreased spontaneity
- decreased phasicity
- abnormal pulsatility
What is used more frequently to determine the severity of the Stenosis?
PSV’s or Peak systolic ratio (V2/V1)
Peak systolic ratio (V2/V1)
Normal PSV RATIOat the distal anastomosis
< 3.0
Volume Flow with optimal FISTULA graft performance? (mL/min)
> 500 mL/min
In a high flow situation the blood flows from the _____ pressure artery to the ____ pressure vein
High;Low
Arterial flow below the anastomosis is?
High resistance
When is hemodialysis necessary?
End Stage Renal disease (ESRD)
Which veins should be evaluated for stenosis?
SCV and Internal jugular
What is the most common cause of failure of graft in the first month?
Thrombosis of the graft
Normal PSV in the outflow vein in dialysis grafts
30-100cm/s
What is Hemodialysis?
Removal of certain elements from the blood through a semi permeable membrane while being circulated outside the body
What are grafts evaluated for? (6)
Stenosis Thrombosis Aneurysms Pseudoaneurysms hematomas arterial steal from the hand
When AVF is not an option and AV ____ can be used
Graft
What depth from the skins surface is required for successful dialysis acess?
5mm
A normal Hemodialysis waveform displays ____ flow, is ___ resistance and has______ PSV and EDV
High;Low;Increased
Define STEAL syndrome
reversal of flow in the ulnar or radial artery
May indicate “stealing” due to low pressure upstream from the wrist (SEE PICTURES)
Arterial flow above the anastomosis is?
Low resistance
What is an AV fistula
connection of artery and vein
Type of Grafts (2)
- Straight graft
2. Loop Graft
Significant stenosis appearance on color/greyscale (4)
- Decreased lumen
- color jet
- increased velocities
- post-stenotic turbulence
What is an AV fistula trying to accomplish?
High flow situation
AGAIN
Normal PSV for fistulas and grafts
<400 cm/s
Normal PSV RATIO in the outflow vein & Dialysis grafts/fistulas
< 2.0
Normal PSV for Dialysis Grafts
100-400 cm/s
Volume flow for suboptimal graft performance
<800mL/min
Volume flow for suboptimal fistula performance
<500mL/min
Volume Flow with optimal dialysis graft performance? (mL/min)
> 800 mL/min
In a venous anastomosis of a prosthetic graft a significant stenosis (>50%) has a PSV of
> 400 cm/s
In a venous anastomosis of a prosthetic graft a significant stenosis (>50%) has a PSV RATIO (V2/V1)
> /= 1.9
AV graft used a_____ or _____ as a channel.
Prosthetic graft; Vein
Normal EDV for Dialysis Grafts
60-200 cm/s
AV ANASTOMOSIS significant stenosis (>50%) has a PSV RATIO (V2/V1)
> 3.0
Hemodialysis required _____ flow in and easily accessed vessel that can tolerate multiple punctures with catheters
High
Arterial inflow and venous outflow of a AV fistuala significant stenosis (>50%) has a PSV RATIO (V2/V1)
> 2.0
Types of Fistulas (2)
- End to Side
- Side to Side
(cephalic to radial)