POCUS - DVT

Question 1

Review the scans needed for a LE DVT scan.

Answer 1

From the groin (CFV) through the SFV to the knee (popliteal vein). Compress all the way.

Some places record a continuous view of the vein the whole way, and some places just do spot check of proximal and distal.

Make sure each area is compressible. In the CFV view, use Doppler in the longitudinal view to look for the biphasic wave. The absence of a biphasic doppler is indicative of proximal obstruction.

Question 2

How many DVTs occur per year in the US?

Answer 2

2 million

Question 3

What percent of DVTs will progress to PEs if untreated?

Answer 3

50%

Question 4

True or false: you need to apply Doppler in a DVT study

Answer 4

False

Compressibility is all you technically need. Some people do Doppler for style.

Question 5

What transducers can you use for the DVT study?

Answer 5

Usually you use the linear probe, but in obese adults you may need to use the curvilinear.

Question 6

What patient position helps in this study?

Answer 6

Reverse Trendelenberg with leg slightly externally rotated

Question 7

The femoral artery is ________ to the femoral vein.

Answer 7

lateral

Question 8

As you begin your DVT scan from the groin, you will see two vessels: the CFA and the CFV. As you go down, you notice that one of the vessels bifurcates. Which one was it?

Answer 8

The CFA

As you move your probe inferiorly, the CFA bifurcates into the superficial FA and the deep FA.

Below that you will see the greater saphenous vein break off of the CFV.

Question 9

The ___________ is lateral to the CFA.

Answer 9

femoral nerve

Question 10

As you move your probe inferiorly, the CFV splits into the ______________.

Answer 10

SFV and the DFV (these parallel their arterial counterparts)

Question 11

Venous duplication is common at the _________ level, so be sure to do a quick scan for other veins (you don’t want to miss a clot in the duplicated vein).

Answer 11

SFV

Question 12

When the CFV splits into the SFV and DFV, the veins are __________ (internal or external) to their arterial counterparts.

Answer 12

internal

So the SFV is deep to the SFA and the DFV is superficial to the DFA.

Question 13

Near the ____________ it is normal for the SFV to not be compressible with transducer probe pressure alone. You need to do manual pressure with your other hand from the posterior side in addition to anterior probe pressure.

Answer 13

adductor canal

Question 14

When you are scanning the popliteal area, have the patient in what position?

Answer 14

Supine with knee flexed and hips slightly externally rotated

Question 15

You scan the popliteal vein and find it just above the PA. When you slide your probe inferiorly you see two smaller triplets of vessels superficial to the PV and PA. What are these?

Answer 15

The gastrocnemius vessels

The gastroc arteries are in the middles of the triplets with a pair of veins on either side

Question 16

You should find the __________ branch off of the PV because if there is a clot at the junction then you need to treat.

Answer 16

lesser saphenous vein

Question 17

If you feel like you’re pressing hard enough on the veins but aren’t sure, what can you look for to know?

Answer 17

If you see tenting of the arteries (evidence that it’s being squished), then the veins should be compressing with that level of force.

Question 18

The most common spot for DVTs is the ____________

Answer 18

popliteal vein

Followed by SFV, DFV, and CFV.

Question 19

What test can diagnose DVTs proximal to the CFV?

Answer 19

Put doppler on the CFV. It should have a biphasic, undulating appearance. If the doppler wave is flat, this is suggestive of proximal occlusion.

Question 20

When you are evaluating for clot, be sure to fully ______________.

Answer 20

compress

Partial compressibility is not diagnostic.

Question 21

Although differentiating an acute clot from a chronic clot is not always possible, what are some features that suggest an acute clot and a chronic clot?

Answer 21

Acute:
- Mobile edge

Chronic:
- Web-like structure with canalization

Question 22

Trace the paths of the LSV and GSV.

Answer 22

LSV originates on the dorsum of the foot and tracks laterally across the ankle then posteriorly up the calf to join the PV.

GSV originates superior to the medial malleolus then tracks medially up the leg to join the CFV.

Question 23

True or false: positive color flow rules out clot.

Answer 23

False

A non-obstructive clot can have color flow.

Question 24

Even though you only need to record the CFV, SFV, and PV, you should check for continuous compressibility. Why?

Answer 24

You could miss a focal thrombus if you did not check for continuous compressibility.

Question 25

Venous duplication at the SFV or PV occurs in what fraction of people?

Answer 25

1/3

Question 26

Superficial thrombosis within ____ cm of the saphenofemoral junction warrants treatment.

Answer 26

5