MedlinePlus Medical Encyclopedia: Plethysmography

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Plethysmography

Contents of this page:
Illustrations Alternative names Definition How the test is performed How to prepare for the test How the test will feel	Why the test is performed Normal Values What abnormal results mean What the risks are Special considerations

Illustrations

Plethysmography

Alternative names Return to top

Arterial plethysmography

Definition Return to top

This test measures the systolic blood pressure (maximum pressure exerted when the heart contracts) of a leg compared to the arm. The test is usually performed to rule out blockages in the arms or legs (usually legs).

See also blood flow studies.

How the test is performed Return to top

This test may be done in the health care provider's office or in a hospital. You are placed in a partially propped-up position. Three blood pressure cuffs are wrapped snugly around the arm and leg. They are inflated to 65 mmHg (millimeters mercury), and a pulse volume recorder (plethysmograph) measures the pulse waves from each cuff.

Any differences between the pulse waves are noted. If there is a reduction in any of the waves compared with the others, it may indicate a blockage. When the test is complete, the blood pressure cuffs are removed.

How to prepare for the test Return to top

Refrain from smoking at least 30 minutes before the test. Remove all clothing from the arm and legs.

Infants and children:
The preparation a parent can provide for this procedure depends on the child's age, previous experiences, and level of trust. For specific information regarding how you can prepare your child, see the following:

infant test or procedure preparation (birth to 1 year)
toddler test or procedure preparation (1 to 3 years)
preschooler test or procedure preparation (3 to 6 years)
schoolage test or procedure preparation (6 to 12 years)
adolescent test or procedure preparation (12 to 18 years)

How the test will feel Return to top

There should be minimal discomfort with this test. The pressure of the blood pressure cuff is all you should feel.

Why the test is performed Return to top

The test is done to help rule out arterial blockages in the arms or legs.

Normal Values Return to top

There should be less than 20 mmHg difference in the systolic blood pressure of the leg compared to the arm.

What abnormal results mean Return to top

Abnormal results may indicate arterial occlusive disease, trauma to the arteries, small vessel diabetic changes, blood clots, and vascular diseases.

Additional conditions under which the test may be performed:

deep venous thrombosis

What the risks are Return to top

There are no risks associated with this test.

Special considerations Return to top

The test is not as accurate as an arteriography. This may be done for seriously ill patients who cannot be transported to the arteriography laboratory.

Update Date: 7/23/2003

Updated by: Hebe Molmenti, M.D., Ph.D., Private practice specializing in Plastic and Reconstructive Surgery, Baltimore, MD. Review provided by VeriMed Healthcare Network.

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