Things You'll Need

Instructions

1

Place the patient in a supine position and rest for 10 minutes.
2

Record the systolic blood pressure of both arms. Wrap the sphygmomanometer around the arm about 1 inch above the elbow. Use the ultrasound to locate the pulse of the brachial artery, located in the middle of the upper arm. Inflate the cuff of the sphygmomanometer to approximately 160 mm Hg or at least 20 mm Hg higher than when the pulse disappears. Slowly release the air of the cuff until you hear the pulse return for two consecutive beats. Record this number as the systolic pressure.
3

Wait two minutes and repeat the measure. Average the two left recordings together and average the two right recordings together. The higher pressure between the left and right arm will be the brachial pressure used.
4

Record the systolic blood pressure for the right posterior tibial and dorsal pedis arteries. The posterior tibial artery is located on the inside of the leg between the bony protrusion of the ankle and the Achilles tendon. The dorsal pedis artery is on the top of the foot below the ankle. Wait two minutes and repeat the measure. Average the two recordings to obtain the average pressure for the right posterior tibial and right and dorsal pedis arteries. The higher pressure between the tibial and dorsal arteries will be the ankle pressure used for the right ankle.
5

Record the systolic blood pressure for the left posterior tibial and dorsal pedis arteries. Wait two minutes and repeat the measure. Average the two recordings to obtain the pressure for the left posterior tibial and left and dorsal pedis arteries. The higher pressure between the tibial and dorsal arteries will be the ankle pressure used for the left ankle.
6

Calculate the right ABI, which is equal to the highest right average ankle pressure (dorsal or tibial) divided by the brachial pressure.
7

Calculate the left ABI, which is equal to the highest right average ankle pressure (dorsal or tibial) divided by the brachial pressure.