What is the purpose of a FAST exam in field trauma when available?

• A. To assess airway patency
• B. To evaluate extremity fractures
• C. To rapidly detect intra-abdominal bleeding or pericardial tamponade
• D. To screen for pulmonary embolism

Answer: (C)

The FAST exam in field trauma is used to rapidly identify life-threatening internal bleeding and cardiac tamponade with bedside ultrasound. In a patient who is unstable, detecting free fluid in the abdominal cavity or a pericardial effusion can confirm ongoing hemorrhage or tamponade, signaling the need for urgent intervention or rapid transport to definitive care. This tool is specifically about detecting intraperitoneal bleeding and pericardial fluid, not about assessing airway patency, extremity fractures, or screening for pulmonary embolism. Its value lies in giving a quick, noninvasive glimpse of potential sources of shock so you can act fast, while also recognizing that a negative FAST doesn’t completely rule out injury and should be considered alongside the overall exam and vitals.