Term
| What is the Trendelenburg test used test for and describe how it is performed? |
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Definition
The test is used to determine the presence of venous outflow obstruction A tourniquet is placed around the proximal thigh with the patient standing. The patient then assumes the supine position and the leg is elevated 45 degrees The tourniquet is removed and the time required for the leg veins to empty is recorded. This is compared to the contralateral leg The test may demonstrate obstructive venous disease |
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Term
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Definition
To distinquish between valvular insufficiency in the deep, perforator and superficial systems and screening for DVT A tourniquet is placed around the proximal thigh with the patient standing. When the patient walks, a decrease in the size of the varicose veins suggests a primary process without deep venous disease Secondary varicose veins (deep obstructive) do not change in caliber In the setting of acute DVT, they may increase in size If the patient notes pain (venous claudication) it may imply an obstruction in an iliofemoral segment as a result of obstruction to flow in both the deep and superficial systems |
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Term
| What is the Schwartz/percussion test? |
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Definition
Venous insufficiency in a segment is demonstrated by placing one hand on a segment of vein and tapping with the other. Transmitted pulse implies insufficiency of the segment |
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Term
| What is the range of normal venous refilling time? |
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Definition
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Term
[image][image] Fill in arrow equivalents |
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Definition
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Term
In the graph, what is the venous refilling time? Expl |
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Definition
The horizontal line until the volume plateaus It is the time from lying down to standing up until maximal filling volume, usually longer than 25 sec In venous reflux it is shorter because of venous flow back into the limb |
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Term
| Explain the ejection volume and where it is on the graph |
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Definition
With a single dorsiflexion, the volume will drop briskly EV |
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Term
| What is the venous volume on the graph? |
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Definition
The volume in the leg lying down to the plateau volume In other words the Y axis |
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Term
| How do you calculate the ejection fraction? |
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Definition
| It is the ejection volume divided by the venous volume |
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Term
| How is the residual tested and calculated |
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Definition
The patient performs 10 brisk dorsiflexions, which will produce a reduction in the Y axis. The difference between the baseline volume and the volume after 10 dorsiflexions |
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Term
| How does venous refilling time relate to patients with venous ulceration? |
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Definition
| Pts with venous ulcers often have a refilling time of less than 10 secs |
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Term
| What is a normal ejection fraction? |
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Definition
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Term
| What is the average ejection fraction in patients with superficial venous insufficiency? |
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Definition
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Term
| What is the average ejection fraction for patients with deep venous insufficiency? |
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Definition
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Term
| What is the ejection fraction for patients with a deep venous obstruction? |
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Definition
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Term
Explain the residual volume fraction and give the formula to calculate it
Should it be higher or lower in a normal limb?
What is the normal residual volume fraction under? |
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Definition
It is the percentage of residual volume compared to the venous volume RV/VV
Lower
<35% |
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Term
| What is the significance of an elevated residual volume fraction? |
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Definition
| The patient has venous hypertension |
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Term
| In what normal anatomical situation will the valsalva manuever fail to demonstrate reflux at the SFJ or CFV? |
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Definition
| If there is a competent valve in the iliac system protecting an incompetent vein |
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Term
In photoplethysmography what diagnostic tool is used? On what principle is the change in blood volume based? How is the test performed? |
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Definition
Infrared light That Hgb absorbs light. If less light is reflected back to a sensor there is more blood in the limb Sensor placed 10cm above the medial malleolus Pt sitting 8 active dorsiflexions |
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Term
In photoplethysmography, what is the normal venous refilling time?
How is the exercise portion of this test performed? Where does this show on the graph? |
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Definition
25 seconds
With the patient sitting, eight brisk dorsiflexions are performed. These are the spikes resulting in a rise in the Y axis. (Remember photoplethysmography measures reflected light. The less volume the more light reflected back to the transducer, rise in the Y axis) |
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Term
In the following picture identify normal Grade 1 2 and 3 venous insufficiency by photoplethysmography What are the different slopes to the curve What are the normal and abnormal values associated with them [image] |
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Definition
bottom nl greater than 25 sec Left grade 1 25-20 sec middle Grade 2 10-20 sec right Grade 3 less than 10 secs[image] |
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Term
| In plethysmography generally what does the X and Y axis represent? |
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Definition
Y axis is volume X axis is time |
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Term
What is the ejection fraction in
Normal patients
Superficial venous insufficiency
Deep venous insufficiency
Deep venous obstruction |
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Definition
Normal >60%
Superficial venous insufficiency average 50%
Deep venous insufficiency average 40%
Deep venous obstruction average 35% |
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Term
How can plethysmography be used in the dx of DVT?
What are the two measures of venous hemodynamics obtained from this method? |
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Definition
If an occluding cuff is placed proximal to the plethysmograhic transducers eg thigh cuff and inflated, venous blood in the deep system can not pass under the cuff until the venous pressure reaches the occluding pressure. Once this venous volume plateaus, the cuff is released.
The volume from the baseline to the plateau is called the segmental venous capacitance (SVC) and represents the blood storage capacity of the segment vein.
The second measure is the slope of the volume time curve when the cuff is released and is known as the maximum venous outflow (MVO). This represents resistance to flow in the deep system. |
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Term
What percent reduction in segmental venous capacitance in comparison to the opposite extremity suggests deep venous obstruction?
Maximum venous outflow reduction?
In what area of venous disease does SVC and MVO provide unique information? |
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Definition
A reduction of 25% in both instances suggests deep venous obstruction
Venous collateralization after DVT result in normalization of the SVC and MVO and carry with it a better prognosis |
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Term
What angle should the probe be held in CW doppler?
What frequency transducers are used in CW doppler? |
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Definition
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Term
| How is photoplethysmography used to determine the efficiency of the calf muscle pump? |
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Definition
| Patients lie on their back and the leg is elevated for a count of eight. Patients then assume a sitting position for the refilling portion the test. The difference in the height of this curve divided into the same number obtained with 8 dorsiflexions gives a fraction when multiplied by 100 estimates the efficiency of the calf muscle pump. |
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