The patient lies in a supine position. A blood pressure cuff is placed around the upper arm to measure the systolic blood pressure in the brachial artery. The same procedure is repeated for the ankle using a Doppler device to locate the pulse and measure the systolic pressure. ABI is calculated by dividing the systolic pressure at the ankle by the systolic pressure in the arm.
Nurses must ensure that the patient is relaxed and that the equipment is properly calibrated to obtain accurate readings.
