Normal Pressures

1. How does the blood pressure in the legs compare with that in the arms?

ANS: With a proper-size cuff over the thigh, the popliteal systolic pressure should be either the same or as much as 20 mmHg higher than in the arms. If the systolic pressure in the legs is lower than that in the arms, occlusive disease anywhere beyond the origin of the subclavian arteries should be suspected.

The usual commercial leg cuff, such as that shown here, must be rolled diagonally around the thigh, to keep the edges snug against the skin. The systolic blood pressure in the legs should not be over 20 mmHg higher than in the arms

Where is the most reliable place to auscultate for blood pressure in the legs? ANS: Over the popliteal artery with the large cuff on the thigh. (A bell chest piece is used.)

Note: Compressing the thigh with a blood pressure cuff can cause enough discomfort to cause a false elevation of pressure. When an accurate comparison with the brachials is necessary, as in patients with suspected coarctation or AR, the arm and thigh measurements should be done by two persons simultaneously.

3. How is the blood pressure taken in the lower legs?

ANS: Place an arm cuff just above the malleolus (i.e., as close as possible to the posterior tibial artery) but without including the protuberance of the malleolus. Use a small (pediatric) bell to auscultate the posterior tibial artery. If no Korotkoff sounds are audible, auscultate or palpate the dorsalis pedis instead. If no Korotkoff sounds are present over any foot artery, the Doppler method can be used.

A convenient method of taking a leg pressure if you do not have a thigh cuff. A pediatric bell should be used to achieve an easy air seal behind the medical malleolus.

4. What are the disadvantages of using the foot rather than the thigh for taking a blood pressure?

ANS: a. No Korotkoff sounds can be elicited over the posterior tibial or dorsalis pedis in about 10% of patients.

b. Marked peripheral constriction, as in a cold room, may cause the blood pressure to be as much as 50 mmHg lower in the foot than in the arm.

5. How is blood pressure taken in an infant?

ANS: a. By the flush method: the limb is raised until it is blanched (some bind the forearm with a bandage to empty it of blood first). Then the cuff is inflated. The first distal flush as the cuff is deflated is read as the mean pressure. b. By Doppler ultrasound: with a cuff about 2.5 cm wide, a systolic pressure can be obtained.

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Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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