15 Principles of Ultrasound in Trauma

Fundamental Physics Behind Ultrasound Imaging

Ultrasound imaging, or sonography, utilizes high-frequency sound waves to create images of internal body structures. These sound waves are emitted from a probe and reflect off tissues, organs, and fluids within the body. The returning echoes are captured by the probe and transformed into visual images by the ultrasound machine. The principles of reflection, refraction, and attenuation are key to understanding how different structures appear on the ultrasound screen.

Components of the Ultrasound Machine and Optimal Settings for Trauma Assessment

• Transducer (Probe): The transducer emits and receives sound waves. In trauma, a curvilinear low-frequency probe is commonly used for its deeper penetration and a linear high-frequency probe for superficial structures and thoracic assessment.
• Control Panel: Includes knobs and switches to adjust the machine’s settings, such as depth, gain (brightness), and focus, to optimize image quality.
• Display Screen: Where the processed images are displayed.
• Optimal Settings: In trauma settings, the depth should be adjusted to visualize the entire area of interest, the gain set to clearly distinguish between fluid (appearing anechoic or black) and tissue, and the focus positioned at the level of interest.

Patient Safety and the Efficacy of Ultrasound in Emergency Settings

Ultrasound is a safe diagnostic modality without the risks of ionizing radiation, making it ideal for repeated use in trauma settings. Its efficacy lies in its ability to provide rapid, real-time images to guide immediate clinical decisions. It is especially beneficial in unstable patients where transport to other imaging modalities may be risky.