Sunday, October 20, 2013

Extremity Vascular Injury



Any injured extremity should be thoroughly evaluated for a possible vascular injury. The presence of obvious arterial injury from a blunt and/or penetrating mechanism rarely requires imaging and should not delay emergent operative exploration.  The presence of “hard signs” strongly supports vascular injury and typically necessitates emergent repair. These “hard signs” are:

1.  Bruit/Thrill
2.  Active/Pulsatile hemorrhage
3.  Pulsatile/Expanding hematoma
4.  Signs of limb ischemia and or compartment syndrome including the 5 "P's" - pallor, paresthesias, pulse deficit, paralysis, and pain on passive extension of the compartment (pain on passive extension is the earliest and most sensitive physical finding)
5.  Diminished or absent pulses with + Doppler signals (this is not a sensitive prognostic finding, as up to 30% of patients with major vascular injuries requiring repair have normal pulses or Doppler signals distal to the injury due to collateral flow)
[1]

The Arterial Perfusion Index, API, is a validated tool for screening for peripheral vascular injury[2]. This is performed by placing a blood pressure cuff above the ankle or on the bicep of the limb of concern. The systolic pressure is determined with a Doppler probe at the dorsalis pedis or brachial artery. Repeat this procedure on the ipsilateral uninjured limb.  The API is calculated by dividing the systolic pressure in the injured limb by the systolic pressure in the uninjured limb. An API < 0.9 has a sensitivity of 95% and specificity of 97% for a major arterial extremity injury. In a study on blunt orthopedic extremity injuries the negative predictive value is 100% for an API > 0.9 to exclude an arterial injury.[3-5]
           
The purpose of these algorithms is to diagnose the occult injury early before irreversible tissue ischemia is present. In patients where the “hard” signs are NOT present it is imperative to maintain a high suspicion of peripheral vascular injury in the injured extremity [2, 6, 7]. If “hard signs“ are not present but peripheral vascular injury is suspected then expedient consultation with Vascular Surgery is indicated and the use of imaging, per Vascular Surgery, should be liberal to avoid missed injuries. 

References:
1.            Drapanas, T., et al., Civilian vascular injuries: a critical appraisal of three decades of management. Ann Surg, 1970. 172(3): p. 351-60.
2.            Bravman, J.T., et al., Vascular injuries after minor blunt upper extremity trauma - pitfalls in the recognition and diagnosis of potential "near miss" injuries. Scand J Trauma Resusc Emerg Med, 2008. 16(1): p. 16.
3.            Mills, W.J., D.P. Barei, and P. McNair, The value of the ankle-brachial index for diagnosing arterial injury after knee dislocation: a prospective study. J Trauma, 2004. 56(6): p. 1261-5.
4.            Lynch, K. and K. Johansen, Can Doppler pressure measurement replace "exclusion" arteriography in the diagnosis of occult extremity arterial trauma? Ann Surg, 1991. 214(6): p. 737-41.
5.            Johansen, K., et al., Non-invasive vascular tests reliably exclude occult arterial trauma in injured extremities. J Trauma, 1991. 31(4): p. 515-9; discussion 519-22.
6.            Dennis, J.W., et al., Validation of nonoperative management of occult vascular injuries and accuracy of physical examination alone in penetrating extremity trauma: 5- to 10-year follow-up. J Trauma, 1998. 44(2): p. 243-52; discussion 242-3.
7.            Gelberman, R.H., J. Menon, and A. Fronek, The peripheral pulse following arterial injury. J Trauma, 1980. 20(11): p. 948-51.