Dispo to Operating Room, Angiography Suite or Observe?
Not all of us work in busy trauma centers. And even for those of us who do, it can sometimes be confusing to manage suspected vascular trauma of the extremities. In last month’s EM:RAP, Mel interviewed our favorite trauma surgeon, Dr. Kenji Inaba, who has a real knack for breaking things down in a clear, straightforward way. Dr. Inaba’s main message was that the disposition of patients with potential vascular injuries of the extremities should be based on the bedside assessment, not imaging studies. This approach makes a lot of sense to us, so we would like to share it with you here. It’s short and sweet – and it applies to both patients with penetrating and blunt mechanisms of injury.
First, there are the patients who need to go to the operating room immediately. An emergent surgical consultation, at minimum, should be sought. These are the ones with so-called hard signs. This includes: a very large, expanding or pulsatile hematoma, a pulseless extremity, or rarely, a bruit or thrill over the affected area. Dr. Inaba also includes patients with significant uncontrolled bleeding and those who are in hemorrhagic shock in the hard findings group. In the event that a patient who is rushed directly to the operating room does require imaging, conventional angiography can be performed on the OR table.
Second, there is a group of patients that have no signs. Pulses are intact and there is no active bleeding. There may be a wound close to a known vascular structure but so long as there are no signs of circulatory compromise, this does not influence initial management. For this group, the recommended strategy is to perform ankle-brachial or brachial-brachial indices (ABIs and BBIs). ABIs are not difficult to perform and require only a blood pressure cuff and a handheld Doppler unit. The blood pressure cuff is inflated proximal to the site of injury and auscultation of a vessel distal to the injury is used to determine the systolic blood pressure (first audible pulse). This number is then compared with the same measurement in the unaffected opposite limb. If the ratio of systolic pressures is >0.9, then either observation or discharge home are appropriate depending on other factors such as an associated fracture prone to compartment syndrome, as well as the patient’s other injuries and co-morbidities.
This leaves the last group, the one in the middle, who have only soft signs, such as a non-expanding hematoma and venous oozing. Although there is no need for emergent transfer to the operating room, a significant number of these patients will have an injury requiring surgical management. These patients are the ones that are most appropriate for advanced imaging. At most centers, this means CT angiography. CT angiography has multiple advantages over conventional catheter-based angiography, including far less complications, no need for a radiologist to perform an invasive procedure and less exposure to contrast and ionizing radiation. Data is mounting that the sensitivity and specificity of CT-angiography is comparable to the conventional gold standard. Doppler ultrasound is another option, but it is significantly less sensitive than both catheter-based and CT-angiography. It is also rather operator dependent, especially in patients with marked overlying soft tissue injury.
Hopefully, this serves as a helpful reminder of the stratification of vascular injuries of the extremities. Of course there are still grey zones, and in the case that Mel presented at the beginning of the discussion with Dr. Inaba, there was initially a disagreement over whether a large hematoma over the knee of a blunt trauma patient was, in fact, a hard sign. As it turned out, it was – because over a short period of time the hematoma expanded, the compartments became hard and the overlying skin began to undergo necrosis. The patient was then promptly taken to the operating room. Even though a CT angiogram had already identified the source of the bleeding to be a rather small branch vessel, the management was dictated by the patient’s examination – again, underscoring the primacy of the clinical findings.
Dr. Swadron is the Vice-Chair for Education in the Dept of EM at the LA County/USC Medical Center. He is an Assoc. Prof. of Clinical EM at USC’s Keck School of Medicine