Doppler Ultrasound and Special Tests for Peripheral Vascular dieases

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Doppler Ultrasound:
Ankle Brachial Index (ABI) is found using doppler, where the pressure at dorsalis pedis artery and radial artery are found. Then the lower exxtremity pressure is divided by upper extremity and the index is found

Normal ABI = .95 - 1.1

         >1.2   =  The value is falsely elevated, and arterial diseases or diabetes.
0.90 - 0.75  =  Mild arterial disease with intermittent claudication
0.74 - 0.5    = Moderate arterial disease with rest pain
<0.5            = Severe arterial disease usually ending up in amputation.

Speical Tests

     Reflex Test:
Done using doppler in this the Great Saphenous vein is used the extremity should be squezzed proximal to the probe. if there is any valvular incompitence, audible signals will be heard.

     Venous Filling Time: (for arterials and veins)
Patient is in supine (on his/her back) position.
The affected extremity is elevated to empty blood from the superficial veins.  Then the patient hangs the extremity over the edge of the table into a dependent position.  Then the time is taken for the veins on top of the foot to be refilled by blood, and the the time is noted.
Normally time is 15 seconds.
>15 seconds - it is indicative of arterial disease.
<15 seconds - it suggests venous sufficiency.

     Rubor of Dependency
Patient position supine ( on his/her back)
color of both feet is first noted.
affected limb is elevated and held for several seconds and than lowered to original postion.
Note the time taken for the elevated limb to match the normal limb.
In the aterial diseases, it takes longer than 20 - 30 seconds for the color to return. Hands will be bright red in color. If the color returns immediately it shows venous insufficieny.

     Claudication Test: (Mainly for arteries)
Claudication is a painful cramping occuring due to insufficient blood supply to the working muscles.
In this the patient is asked to walk on a treadmill or unobstructed level surface and the time or distance at which the painful symptoms occurs is than recorded.

     Cuff Test: (mainly for DVT) Deep Vein Thrombosis
A blood pressure (B.P) cuff is placed around the lower leg and the cuff is inflated.
If the patient is unable to tolerate the pressure > 40 mm of Hg then there is high probability of an active DVT.
     Homan's Sign: (DVT)
Here the knee is kept in extension and the patients calf region is squeezed by examiner or else passive dorsiflexion of the ankle can be done.
Severe pain is positive for DVT.

     Percussion Test: ( This is for incomplete valves)
Keep the lower limbs in dependent position.  Palpate the Great Saphenous Vein distal to knee with one hand and with the other hand tap the vein 8-9 inches proximal to knee.
If a wave of fluid is detected under the distal palpation site, it indicates an incomplete valve.

     Trendelenburg's Test: (for Valves)
Patient in supine position
Elevate the affected limb approximately 75 degree to allow venous blood to empty. A tourniquet is place around the thigh to prevent sup. venous back flow. Then place lower limb in dependent position.
Normally, the veins would fill 25-30 seconds after the limb is placed in dependent position.  If the superficial veins get filled quickly it shows that the valves of the perforating veins are incompetent.

     Stemmer's Sign:
Performed to classify the presence of lymph-edema.  It is the inability to pick up a fold of skin at the base of 2nd toe of the affected extermity.  Other vascular studies includes air plethysmography, venography and arteriography.

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