Other Venous Conditions/Tests Ch.29-30,32,35

Question 1

Capabilities of Impedance Plethysmography (IPG)

Answer 1

Can detect thrombi in the iliac, femoral, or popliteal veins

Question 2

Limitations of IPG

Answer 2

False positive results- caused by extrinsic compression (tight clothing, tumors, ascites, pregnancy, obesity, improper positioning, pain, or anxiety)
False negative results- chronic venous occlusion with large collaterals
Does not detect isolated calf thrombus

Question 3

Physical Principles of IPG

Answer 3

IPG measures volume changes in a limb by measuring the hindrance to the passage of an alternating electrical current

Question 4

Capabilities of Strain Gauge Plethysmography (SPG)

Answer 4

SPG is used to detect venous obstruction in the large veins above the knee

Question 5

Limitations of SPG

Answer 5

Extreme sensitivity limits its usefulness

extrinsic compression

Question 6

Physical Principles of SPG

Answer 6

Utilizes a mercury-in-Silastic strain gauge that indirectly senses changes in blood volume by measuring the circumference of the limb

Question 7

Capabilities of Air Plethysmography

Answer 7

Can determine the presence or absence of venous insufficiency
Can quantify venous reflux

Question 8

Limitations of air plethysmosgraphy

Answer 8

Cannot be preformed if patient is not able to maintain positions or perform exercise
Presence of a cast, traction, or heavy nonremovable bandages
Cannot be used to diagnose incompetent perforators

Question 9

Physical Principles of air plethysmography

Answer 9

Pneumatic cuff wrapped around the limb detects volume changes

Question 10

Additional testing: Venous Reflux testing with patient in the standing position

Answer 10

With patient standing he/she rests one leg on a stool while the other holds their weight
May evaluate the size of the GSV in this position (measure at prox, mid, distal thigh and prox, mid, distal calf)
May evaluate with an automatic cuff inflator placed on the leg to mimic augmentations and evaluate for reflux.
Patient standing- test popliteal for reflux and test CFV (Valsalva maneuver) for reflux

Question 11

Abnormal Reflux Time

Answer 11

With patient standing:
deep veins > or = to 1 sec
GSV, SSV > or = to 0.5 sec
perforator veins > 0.35 sec
Longer durations observed in supine patients

Question 12

GSV diameter consistent with reflux

Answer 12

SFJ > 9.0 mm
Mid thigh > 7.0 mm
Mid calf > 5.0 mm

Question 13

D-Dimer

Answer 13

Blood test that measures the product in the blood that is present during a thrombotic process going on in the body (anywhere in the body)

Question 14

Positive D-Dimer result

Answer 14

Not really helpful, just shows that there is lysis of a thrombus going on somewhere in the body (lots of false positives for DVT)

Question 15

Negative D-Dimer result

Answer 15

Very helpful , implies the absence of a thrombotic process.

Question 16

Contrast Venography

Answer 16

Goldstandard, however the most reliable method of diagnosing DVT is duplex ultrasound.
Injection of a dye with x-rays.

Question 17

Ascending venography

Answer 17

Dye injected into a vein on the dorsum of the foot.
Used to detect obstruction. Evaluates acute deep venous thrombosis, congenital venous disease and or anomalies, and chronic venous changes.

Question 18

Descending venography

Answer 18

Dye injected into the Common femoral vein.

Used to detect reflux.

Question 19

Venography deviations from normal

Answer 19

a filling defect indicating the displacement of contrast material by thrombus

Question 20

Lung Perfusion Scan

Answer 20

Detects pulmonary embolism in the lungs
Radioactive contrast medium is injected, usually into an arm vein.
Scans are interpreted as representing high, moderate or low probability of pulmonary emblism.

Question 21

Gold standard- in the diagnosis of a PE

Answer 21

Pulmonary angiography

CTA is more sensitive and more readily available

Question 22

Lung Perfusion Scan limitations

Answer 22

emphysema, asthma, pneumonia, cancer of the bronchus, congestive heart failure, liver cirrhosis, radiotherapy, multiple blood transfusions, and postoperative phenomena.

Question 23

Therapeutic Intervention for DVT- Medical therapy

Answer 23

Controlling risk factors-
decrease venous stasis- by limiting long periods of inactivity or bed rest.
Promote venous drainage- wearing support hose or compression stockings, elevation of legs, using intermittent pneumatic calf compression during and after surgery, and reducing weight
trauma/endothelial damage
hypercoagulability states- follow prescribed treatment plan.

Question 24

Medical Therapy for DVT- Anticoagulant Therapy for Prophylaxis

Answer 24

Low dose unfractionated heparin (5000 units subcutaneously every 12 hours before and after surgery, decreases the postoperative risk of DVT).
Low-molecular weight heparin (Lovenox) administered subcutaneously, provides anticoagulation when Coumadin must be discontinued for an invasive procedure.

Question 25

Anticoagulant therapy for acute DVT and/or PE

Answer 25

Loaded dosage of 10,000 units of Heparin followed by continuous intravenous infusion for 5-10 days may be recommended for the treatment of acute DVT.

Question 26

Patients receiving intravenous Heparin

Answer 26

Will be placed on strict bed rest to decrease the risk of an embolic process secondary to muscular contraction.

Question 27

How does Heparin prevent propagation of the clot?

Answer 27

Heparin interferes with the formation of a blood clot by slowing down the conversion of prothrombin to thrombin, increasing the effect of antithrombin III, and decreasing platelet adhesiveness.

Question 28

Lytic therapy is used when…

Answer 28

A patient has an acute iliofemoral thrombosis and or is at risk of limb loss.

Question 29

Partial Thromboplastin Time (PTT)

Answer 29

Time needed for a fibrin clot to form is 1.5 -2 times normal.

Question 30

Low molecular weight Heparin used for outpatient anticoagulation

Answer 30

Lovenox- Administered subcutaneously and after 30 mins of administration the patient is safe to ambulate.

Question 31

Oral anticoagulation

Answer 31

Coumadin- Regulated to ensure that the patient’s prothrombin time (PT) is 1.5-2 times normal.

Question 32

Discontinuing Heparin

Answer 32

Heparin is discontinued after 5-10 days if there is sufficient overlap with Coumadin (min 4 days), if PT and PTT remain at therapeutic levels, and if there are no signs of active thrombosis.

Question 33

Surgical and endovascular therapy- Acute DVT or PE - Vena caval interruption

Answer 33

For patients with acute DVT, who cannot be anticoagulated to prevent a PE

Question 34

Procedure for Vena Caval interruption

Answer 34

Using fluoroscopy and using an interruption device such as a Greenfield or bird’s nest filter placed in the IVC via the jugular vein or FV.

Question 35

External Caval clip

Answer 35

May be placed around the IVC during abdominal surgery to decrease the risk of PE.

Question 36

What are IVC filters used temporarily used for?

Answer 36

IVC filters can be used permanently but also termporarily for certain surgical procedures such as gastric bypass.

Question 37

What is iliofemoral venous thrombectomy used for?

Answer 37

Removal of a clot, performed in a patient with impending limb loss (because of phlegmasia cerulea dolens) Done if thrombolytic therapy does not dissolve the clot.

Question 38

Thrombosis at or near the SFJ vs. isolated superficial system thrombosis

Answer 38

Thrombosis of the GSV at or near the SFJ may require more aggressive treatment then an isolated superficial system thrombosis.(Ligation of the GSV to prevent propagation into the deep system).

Question 39

Thrombosis at or near the saphenopopliteal junction vs. isolated superficial system thrombosis

Answer 39

More aggressive treatment required for thrombosis at or near the saphenopopliteal junction compared with isolated superficial system thrombosis.(Ligation of the SSV to prevent propagation into the deep system).