Johanesen et al used Doppler ultrasonography to identify occult arterial trauma in an injured extremity. The authors are from Harborview Medical Center in Seattle.

Patient selection: injured extremity


Examination: Doppler ultrasonography


(1) systolic arterial pressure in the injured extremity in mm Hg

(2) systolic arterial pressure in an uninvolved arm in mm Hg


Doppler arterial pressure index (API) =

= (systolic arterial pressure in injured extremity) / (systolic arterial pressure in uninvolved arm)



An API < 0.90 is associated with a major arterial injury with a sensitivity of 95% and specificity of 97%.

An API >= 0.90 has a negative predictive value of 0.99 for major arterial lesions. However, minor arterial lesions may be present (arteriovenous fistula, pseudoaneurysm).


Angiography is indicated when the API < 0.90.

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