Emergency Ultrasound
Core concepts
Understand point-of-care ultrasound as an extension of the physical examination. Master the focused assessment with sonography for trauma (FAST) and its role in unstable trauma patients, the RUSH protocol for undifferentiated shock, and the cardiac views for pericardial effusion and cardiac standstill. Learn lung ultrasound for pneumothorax (absent lung sliding) and pulmonary oedema (B-lines), and the focused echo for right heart strain in suspected pulmonary embolism. Understand the limitations: operator dependence, body habitus, and the danger of over-reliance.
Traps
Examiners test that a negative FAST does not exclude retroperitoneal or hollow viscus injury. Lung sliding absent on one side suggests pneumothorax but can also be seen in mainstem intubation. Cardiac standstill on ultrasound carries a poor prognosis but is not an absolute criterion for stopping resuscitation. Do not use ultrasound to delay definitive management.
Rule of thumb
In undifferentiated shock, use the RUSH protocol: pump (heart), tank (IVC and lungs), and pipes (aorta and veins). In unstable trauma, a positive FAST prompts laparotomy; a negative FAST in an unstable patient does not end the workup.
Worked example
A hypotensive trauma patient with a positive FAST in the right upper quadrant: this suggests haemoperitoneum - proceed to urgent laparotomy rather than CT.