Emergency Ultrasound
This domain tests point-of-care ultrasound for FAST, cardiac activity, lung sliding, abdominal aorta, gallbladder, and early pregnancy. The exam expects focused questions, image interpretation, and recognition of limitations.
Core rules
- FAST looks for free fluid in pericardial, perihepatic, perisplenic, and pelvic windows. It is rapid but operator-dependent and does not exclude retroperitoneal bleeding.
- Cardiac views assess effusion, tamponade, global function, and cardiac activity during arrest.
- Lung ultrasound: lung sliding supports normal pleural apposition; absent sliding suggests pneumothorax, but may also occur after pleurodesis or in mainstem intubation.
- Abdominal aortic aneurysm assessment measures maximal aortic diameter; do not delay surgery for ultrasound in an unstable patient.
- Early pregnancy ultrasound can locate intrauterine pregnancy, but a positive pregnancy test with shock still requires resuscitation and urgent gynaecology involvement.
Worked example
A patient with RUQ pain has ultrasound showing gallstones and a thickened gallbladder wall with sonographic Murphy sign. This supports acute cholecystitis; arrange surgical review and antibiotics rather than relying on ultrasound alone.
Traps
- Do not treat ultrasound as a substitute for clinical assessment.
- Do not exclude ectopic pregnancy solely because no adnexal mass is seen.
- Do not miss cardiac tamponade in shock with distended neck veins.
- Do not overcall pneumothorax from absent lung sliding without clinical context.