Ankle–brachial pressure index Ankle–brachial pressure index The ankle-brachial pressure index (ABPI) or ankle-brachial index (ABI) is the ratio of the blood pressure at the ankle to the blood pressure in the upper arm (brachium). Compared to the arm, lower blood pressure in the leg suggests blocked arteries due to peripheral artery disease (PAD). The ABPI is calculated by dividing the systolic blood pressure at the ankle by the systolic blood pressure in the arm. The patient must be placed supine, without the head or any extremities dangling over the edge of the table. Measurement of ankle blood pressures in a seated position will
Brachial plexus block collapse. In severe cases, cardiac dysrhythmia, cardiac arrest and death may occur. Other rare but serious complications from brachial plexus block include pneumothorax and persistent paresis of the phrenic nerve. Complications associated with interscalene and supraclavicular blocks include inadvertent subarachnoid or epidural injection of local anesthetic, which can result in respiratory failure. Because of the close proximity of the lung to the brachial plexus at the level of the clavicle, the complication most often associated with this block is pneumothorax — with a risk as high as 6.1%. Further complications of supraclavicular block include subclavian artery puncture, and spread of