Fundamentals of the eFAST exam

This section is a selection of key principles of the eFAST exam to enhance comprehension and skill development in eFAST. We will outline the necessary knowledge, skills and attitudes to perform the eFAST examination.

Anatomical planes

It is helpful to understand the basic anatomic planes as they pertain to sonographic imaging. Because ultrasound is 2-dimensional, having versatility in different imaging planes is a helpful skill to interrogate potential pathology.

Orientation & set-up

Traditional imaging is with screen marker left and probe marker towards head (longitudinal plane) or screen marker left and probe marker patient right (axial/transverse plane). Cardiology-based imaging places the screen marker right with various probe marker configurations, but is largely opposite to traditional imaging standard.

Probe selection

Each probe has a potential role in the eFAST exam. In general, the phased array is the most versatile for cardiac, thoracic and abdominal imaging. However, the curvilinear with it's low frequency and broad footprint, is also ideal for abdominal imaging. The linear probe is an ideal adjunct for vascular imaging and examination of lung artifacts.

Probe movements

It is crucial to understand probe movements and manipulation. This technical review by Bahner et al. (2016) is a helpful document to understand these principles.

Image interpretation

Every image obtained should be evaluated for key aspects:

  • Orientation: Probe marker, screen marker
  • Depth: Ensure adequate adjustment
  • Angle: Ensure correct image position
  • Gain: Ensure adequate adjustment. Fluid-filled spaces should be black or 'anechoic'.

Echogenicity

Depending on the level of reflection or transmission of the ultrasound wave and surrounding tissue, we see distinct pattern of echogenicities. These distinct patterns are critical to understand.

Limitations & concerns

Here are select concerns of the eFAST exam you must be familiar with. This list is not all inclusive but covers the major pitfalls.

References

Bahner DP, Blickendorf JM, Bockbrader M, et al. Language of Transducer Manipulation. J Ultrasound Med. 2016;35(1):183-188. doi:10.7863/ultra.15.02036.