First10EM - By Justin Morgenstern - August 30, 2021
Bottom line for the FAST Exam
The evidence of benefit is non-existent, but I think there is clearly a role for the FAST exam in hemodynamically unstable patients. However, even among the hemodynamically unstable, the role may be more limited than you think. It is essential to consider your resources, and how the test will change your management. In a trauma center, when you are deciding between the operating room and interventional radiology, the FAST exam may provide invaluable information. In the community, where most of us work, such treatment options don’t exist, and the FAST exam may just be delaying the transfer the patient needs.
In hemodynamically stable patients, I think the available data is pretty clear: the FAST exam shouldn’t be used. The sensitivity is not high enough to rule out intra-abdominal injuries. If you are concerned about a patient, CT is the imaging of choice, and a negative ultrasound may just falsely reassure you. The specificity of the FAST exam is excellent, but many hemodynamically stable patients will be managed non-operatively, so essentially all of these patients are going for CT as well. In other words, whether your FAST exam is positive or negative, the patient still needs a CT, which is the definition of a useless test.