· Palpation and comparison of pulses in the involved and uninvolved upper or lower extremities

· Skin temperature

· Skin integrity and pigmentation

· Tests for reactive hyperemia (rubor of dependence)

· Claudication time

· Ultrasonography, Doppler measurement of blood flow, transcutaneous oximetry

· Magnetic resonance angiography

· Arteriography

Skin Integrity and Pigmentation

Diminished or absent arterial blood flow to an extremity causes trophic changes in the skin peripherally. The patient’s skin is dry, and its color is diminished (pallor). Hair loss and a shiny appearance to the skin also occur. Skin ulcerations may be present.

Rubor Dependency Test-Reactive Hyperemia

Changes in skin color that occur with elevation and dependency of the limb as the result of altered blood flow are determined. Rubor/reactive hyperemia can be assessed in two ways.

Procedure. The legs are elevated for several minutes above the level of the heart while the patient is lying supine. Pallor (blanching) of the skin occurs in the feet within 1 minute or less if arterial circulation is poor. The time necessary for blanching to develop is noted. Then the legs are placed in a dependent position, and the color of the feet is noted.

Normally, a pinkish flush appears in the feet within several seconds after the legs are placed in a dependent position. With occlusive arterial disease, a bright bluish-red color, or rubor, of the distal legs and feet is evident that is caused by reduced blood flow in the capillaries. The rubor may take as long as 30 seconds to appear.

Alternate procedure. Reactive hyperemia also can be evaluated by temporarily restricting blood flow to the distal portion of the lower extremity with a blood pressure cuff. This restriction causes an accumulation of CO2 and lactic acid in the distal extremity. These metabolites are vasodilators and affect the vascular bed of the blood flow-deprived area.

When the cuff is released and blood flow resumes to the distal extremity, a normal hyperemia (flushing) of the extremity should occur within 10 seconds. With arteriosclerotic vascular disease it may take as long as 1 to 2 minutes for a flush to appear, whereas with vasospastic arterial disease (Raynaud’s disease) flushing occurs within the normal time frame.

Skin Integrity and Pigmentation

Diminished or absent arterial blood flow to an extremity causes trophic changes in the skin peripherally. The patient’s skin is dry, and its color is diminished (pallor). Hair loss and a shiny appearance to the skin also occur. Skin ulcerations may be present.

Claudication Time

An objective assessment of exercise pain (intermittent claudication) is performed to determine the amount of time a patient can exercise before experiencing cramping and pain in the distal musculature.

A commonly used test is to have the patient walk at a slow, predetermined speed on a level treadmill (1 to 2 mph). The time that the patient is able to walk before the onset of pain or before pain prohibits further walking is noted.This measurement should be undertaken to determine a baseline for exercise tolerance before initiating a program to improve exercise tolerance.

Doppler Ultrasonography
Doppler measurement of blood flow with ultrasound imaging is a noninvasive assessment that uses the Doppler principle to determine the relative velocity of blood flow in the major arteries and veins. A soundhead, covered with coupling gel, is placed on the skin directly over the artery to be evaluated. An ultrasonic beam is directed transcutaneously to the artery. Blood cells moving in the path of the beam cause a shift in the frequency of the reflected sound.

The frequency of the reflected sound emitted varies with the velocity of blood flow. This information is transmitted visually onto an oscilloscope or printed tape or audibly via a loudspeaker or stethoscope.

Transcutaneous Oximetry

Transcutaneous oximetry provides information about the oxygen saturation of blood by means of a photoelectric device (a pulse oximeter). A beam of red and infrared light passes through a pulsating capillary bed (e.g., in the fingertip). The ratio of red to infrared transmission varies with the oxygen saturation of the blood. Because it responds only to pulsating objects, it does not detect nonpulsating objects, such as venous blood or skin.

Arteriography

Arteriography is an invasive procedure that involves injecting a radiopaque dye (contrast medium) directly into an artery. The arteries are then radiographically visualized to detect any restriction of movement of the dye in arterial vessels indicating a partial or complete occlusion. Collateral circulation can also be visualized. Because arteriography gives a highly accurate picture of the location and extent of an arterial obstruction, it is used most often prior to reconstructive arterial bypass surgery.

Magnetic Resonance Angiography

Magnetic resonance angiography, a noninvasive procedure, provides radiographic visualization of arteries without the use of a contrast medium.

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