Week 4 Part 3

Question 1

Who is hemodialysis for?

Answer 1

those with end stage renal disease

Question 2

What does hemodialysis do?

Answer 2

removes waste products, creatinine, urea and excess water

Question 3

What do sonographer’s look for post-operatively for hemodialysis?

Answer 3

assess fistulas and grafts for defects, stenosis or occlusion
evaluate access for aneurysms, PSA’s and perigraft abscess

Question 4

What are some indications for the exam?

Answer 4

Pre-op
distal limb ischemia
abscence of palpable fistula "thrill"
peri-graft fluids or mass
poor dialysis
elevated pressures during dialysis
assess recirculation of 12% or greater
unexplained urea reduction ratio <60%
difficult cannulation or thrombus aspiration

Question 5

What are the types of access? (3)

Answer 5

central venous catheter
synthetic AV bridge graft
primary AV fistula

Question 6

What are other names for access? (2)

Answer 6

fistula

shunt

Question 7

What’s used for the insertion point for a central venous catheter?

Answer 7

IJV or SCA

temporary

Question 8

Where is a primary AV fistula done on the body?

Answer 8

lower arm or upper arm

Question 9

Primary AV fistula:

Answer 9

surgical procedure that creates a direct connection b/w artery and vein
preferred type
"native" (racist) access fistula
non dominant arm
long term and low complication

Question 10

What is another name for primary AV fistula?

Answer 10

Brescia-Cimino fistula

Question 11

What are the common connections for AV fistula’s?

Answer 11

radial A to cephalic vein (most common)

brachial A to basilic vein

Question 12

When the fistual is created and has matured, the __________ _________ _____ is used for dialysis puncture.

Answer 12

superficial efferent vein

becomes lumpy b/c of intraluminal pressure

Question 13

Synthetic bridge graft:

Answer 13

surgical procedure where a flexible rubber tube is put in to create a path between an artery and v
graft sits under skin
may be straight or looped

Question 14

Synthetic bridge grafts are used in the same way as a fistula except:

Answer 14

the needles used for the hemodialysis are placed into the graft material rather than patient’s own vein

Question 15

When are synthetic access grafts used?

Answer 15

when veins are not accurate
fistulas have failed
50% of candidates are not eligible for AVF

Question 16

Grafts have a shorter duration and lower patency rates than AVF. True or false

Answer 16

True

Question 17

What are access sites for synthetic access grafts?

Answer 17

usually in forearm but if they fail then they move proximal
brachial A to basilic V
subclavian A to jugular V
femoral A to long saph V

Question 18

What are some complications of grafts and fistulas

Answer 18

thrombus/occlusion
locations of stenosis: proximal and distal anastomosis, within graft, and in venous outflow tract due to hyperplasia or thrombus

Question 19

What are some complications of grafts and fistulas con’t

Answer 19

arterial steal 
distal venous hypertension
aneurysm and PSA (common)
elevated right heart pressure due to excessive graft flow
infection (mostly with synthetic grafts)

Question 20

What are the flow findings for normal vessels involved in hemodialysis?

Answer 20

feeding a= monophasic w/ large diastolic component
anastomosis= perivascular tissue vibration; turbulent flow over long stretch
draining vein= pulsatile flow-arterialized

Question 21

What’s the normal volume of flow?

Answer 21

> 500ml/min

Question 22

What type of probe is used for evaluation of grafts?

Answer 22

> 9MHz

Question 23

What do we evaluate once the graft is in?

Answer 23

artery feeding graft, anastomosis, graft body, venous anastomosis and draining vein

Question 24

What are some abnormal Doppler results

Answer 24

venous anastomotic or draining vein stenosis with a PSV ratio of >2 is classified as >50% diameter reduction
stenosis with a PSV ratio >3 indicates a 75% stenosis
this would need to be confirmed with angiography

Question 25

The IJV and SCV should be evaluated for respiratory phasicity and transmitted cardiac pulsations. True or false

Answer 25

True

Question 26

It’s normal to see monophasic flow in the SCV with a stent. True or false

Answer 26

True– assuming no stenosis

Question 27

Arterial steal:

Answer 27

occurs when the venous outflow from the graft exceeds the capacity of the inflow artery
causes graft to “steal” blood from more caudal portions of extremity
causes symptoms of arterial insuffiency

Question 28

A complete steal is the direction of flow is reversed caudal to the graft. True or false.

Answer 28

True

Question 29

Partial steals the spectral waveform is triphasic. True or false

Answer 29

False– biphasic

Question 30

What corrects arterial steal?

Answer 30

graft litigation