Final answer:
A disadvantage of a focused assessment sonography in trauma is that the test can only be used on hemodynamically stable patients.
Step-by-step explanation:
A disadvantage of a focused assessment sonography in trauma (FAST) is that the test can only be used on hemodynamically stable patients. Hemodynamic stability refers to the stable circulation of blood within the body. In the context of trauma, a patient who is hemodynamically stable has a stable blood pressure and heart rate.
The reason FAST can only be used on hemodynamically stable patients is because it is a bedside ultrasound examination performed by the trauma team to quickly evaluate a patient for potential internal injuries. If a patient is not hemodynamically stable, they are at risk of worsening their condition during the examination.
Therefore, it is important to stabilize a patient's hemodynamics before performing a FAST examination to ensure their safety.