Normal exam + normal ABI = no arterial injury
This was as a meta-analysis of several studies to determine the accuracy of exam, ABI, and ultrasound for arterial injury in the setting of penetrating trauma. The gist is that if the physical exam is normal, with no hard signs* or soft signs** of arterial injury, and ABI is normal (0.9 or greater) the post-test probability for arterial injury approached zero. The problem is that soft signs** was variably defined. If ultrasound is positive for arterial injury, CTA can likely be avoided. A normal ABI or normal ultrasound alone could not rule out arterial injury - post-test probability remained 9% and 5%, respectively, which was above the study's predefined testing threshold of 0.14%.
Arterial injury may be ruled out with a careful physical exam showing no hard or soft signs and ABI 0.9 or greater. My practice is, when in doubt, I get a CTA.
Accuracy of Physical Exam, Ankle-Brachial Index, and Ultrasonography in the Diagnosis of Arterial Injury in Patients with Penetrating Extremity Trauma: A Systematic Review and Meta-Analysis Acad Emerg Med. 2017 May 11. doi: 10.1111/acem.13227. [Epub ahead of print]
Peer Reviewed by Thomas Davis.
*Hard signs of vascular injury according to EAST Guidelines.
- active hemorrhage
- rapidly expanding hematoma
- absent pulses
- palpable thrill/bruit
**Soft signs of vascular injury
- non-expanding hematoma
- history of arterial bleeding
- proximity of the wound to an artery
- neurologic deficit