Emergency Ultrasound and Procedural Skills
What the board tests
Whether you can acquire and interpret focused images, integrate them into a decision, and perform common ED procedures safely with ultrasound confirmation.
FAST and eFAST
- Four windows: right upper quadrant (Morison's pouch), left upper quadrant (splenorenal), pelvis (rectovesical or pouch of Douglas) and subxiphoid cardiac.
- FAST detects free fluid, not organ injury; a negative scan does not exclude injury, so repeat it or proceed to CT in the stable patient.
- eFAST adds lung sliding: absent sliding suggests pneumothorax, and finding the lung point confirms it. B-lines indicate interstitial fluid, not pneumothorax.
Cardiac, vascular and abdominal
- Views: parasternal long axis, apical four-chamber and subxiphoid. Tamponade shows an effusion with right ventricular diastolic collapse; a dilated right ventricle suggests PE or cor pulmonale.
- Abdominal aorta: measure outer wall to outer wall; 3 cm or more is aneurysmal.
- Hydronephrosis: anechoic dilation of the renal pelvis and calyces; grade it and correlate with the bladder.
- Gallbladder: wall thickness over 3 mm, pericholecystic fluid and sonographic Murphy sign support cholecystitis.
Procedures
Use ultrasound for central venous access (internal jugular, femoral, subclavian), arterial lines, arthrocentesis, abscess drainage, peripheral IV and intraosseous confirmation. Prepare sterilely, identify the vein and any overlying artery, and confirm needle and wire position before dilation. For arthrocentesis, avoid the neurovascular bundle and send fluid for cell count, crystals and culture.
Worked example
A hypotensive patient after blunt abdominal trauma has free fluid in Morison's pouch and the pelvis on FAST, with a systolic of 80 mmHg after 1 L of crystalloid. This is a positive FAST in an unstable patient: activate the massive transfusion protocol and go to laparotomy. Reasoning: in the unstable patient, ultrasound replaces diagnostic peritoneal lavage and CT; the finding itself is an indication for surgery.
Traps
Calling the pericardial fat pad an effusion; mistaking comet-tail artifact for a B-line; scanning only one hemithorax for pneumothorax; using ultrasound to delay a needed intervention; failing to confirm wire position in the vein before dilating.