Frequency of incomplete abdominal aorta visualization by emergency department bedside ultrasound

To determine how often emergency physicians (EPs) scanning the abdominal aorta (AA) of nonfasted emergency department (ED) patients are able to visualize the entire AA.

The authors performed a retrospective study of patients receiving ultrasound (US) by EPs to rule out abdominal aortic aneurysm (AAA) at a suburban Level I ED. For patients being evaluated for possible AAA, EPs evaluated the entire length of the AA with US in short axis, making standard proximal, middle, and distal measurements. AAA was defined as dilation of the AA to >3 cm. Video of each US and data sheets were evaluated by a hospital-credentialed sonologist for visualization of the AA. Any portions of the AA not visualized were noted. If one third or more of the length of the AA was not seen, the examination was considered inadequate, allowing for potentially missing an AAA. Statistical analysis included descriptive statistics.

Ultrasounds of 207 patients were completed. In 35 patients (17%), a portion of the AA less than one third its length was not seen. In 17 patients (8%), a significant portion of the AA (at least one third its length) could not be visualized and therefore could have potentially concealed an AAA. In four patients, the AA could not be seen at all. There were 29 AAAs discovered (14%), and none were missed.

Significant portions of AA (at least one third of its length) were not visualized on bedside US in 8% of nonfasted patients; this rate is higher than radiology studies of fasted patients receiving US for evaluation of their aortas.