AAA and Emergency Medicine

The use of ultrasound by emergency physicians is becoming increasingly popular in the UK. The immediacy and availability of bedside ultrasound in the emergency department means that critical management decisions can be made earlier.

As the clinical assessment of the abdominal aorta for AAA has shown to be unreliable [2], one of the key roles, identified internationally for emergency physician performed ultrasound, is early identification of abdominal aortic aneurysms (AAA). Internationally, studies have demonstrated that emergency physicians can accurately perform aortic ultrasound scans with relatively little training [3-6].

In the emergency setting it is usually difficult to define the limits or relations of the aneurysm, so we would usually concentrate on the single issue of whether it is aneurysmal or not.

Similarly, ultrasound is not accurate in determining the presence of a leak from the aneurysm. Again we concentrate on whether aneurysmal change is present or not.

The current evidence for the diagnostic ability of emergency physician ultrasound, for detection of AAA, is based on a number of international small cohort studies [3-6]. These series report high sensitivities (94100 %) and specificities (98100 %).

UK emergency physicians can accurately and usefully undertake emergency ultrasound scans to detect AAA, with a sensitivity comparable to that obtained internationally.

Emergency ultrasound, performed by UK emergency physicians, has been reported as having the following accuracy profile for the detection of AAA[7]:

• Sensitivity of 96.3 % (95 % confidence interval (CI), 81.0 % to 99.9 %)
• Specificity of 100 % (95 % CI, 91.8 % to 100 %)
• Negative predictive value of 98.6 % (95 % CI, 88.0 % to 99.9 %)
• Positive predictive value of 100 % (95 % CI, 86.8 % to 100 %)