BloodSweatxED
PRN Education · No. 013 · POCUS Series

eFAST
Exam.

The extended Focused Assessment with Sonography in Trauma asks one thing fast: is there free fluid or air where there shouldn't be? Four windows for blood in the abdomen and pericardium, plus the lungs for pneumothorax and hemothorax.

In the hypotensive trauma patient, a positive eFAST is a ticket to the OR — not to the CT scanner.

Source

Curated from the POCUS 101 FAST / eFAST Ultrasound Exam Made Easy: Step-By-Step Guide. Their labeled images of each window and positive scans are the fastest way to calibrate what free fluid looks like.

When to scan

And what a negative does not mean

Reach for the probe

  • Blunt or penetrating torso trauma
  • Hypotension after injury — find the blood
  • Suspected pericardial effusion or tamponade from penetrating chest trauma
  • Suspected pneumothorax or hemothorax
  • Serial exams during resuscitation — the scan is fast and repeatable

Know the limits

  • A negative FAST does not exclude injury. It has limited sensitivity for small volumes, and misses most retroperitoneal and solid-organ injuries without free fluid. Repeat it, and image definitively in the stable patient.
  • Ultrasound cannot distinguish blood from ascites, urine, or bowel content — interpret the fluid in clinical context.
  • It does not grade organ injury; a stable patient with a positive FAST still needs CT.

Setup

One probe, dependent spaces

Probe

Curvilinear

Abdominal preset for the fluid windows; switch to a linear probe (or high-frequency) for the anterior thoracic pneumothorax views.

Position

Supine

Free fluid pools in the most dependent spaces of a supine patient. Trendelenburg increases sensitivity for small volumes if the situation allows.

Look for

Anechoic stripe

Blood is anechoic (black) and collects in potential spaces that are normally closed — a black line where two organs meet.

The scan

Four fluid windows, then the lungs
eFAST WINDOWS · ANTERIOR TORSO 4 1 2 3 5 5 4 · Subxiphoid cardiac pericardial effusion / tamponade 2 · LUQ (perisplenic) fluid collects above the spleen first 3 · Suprapubic retrovesical / pouch of Douglas 1 · RUQ (Morrison's) hepatorenal — most sensitive 5 · anterior thorax = pneumothorax
Fig. 1 — Four free-fluid windows (red) plus bilateral anterior thoracic views (blue) for pneumothorax; add lung bases for hemothorax. RUQ is the single highest-yield window.

RUQ — Morrison's pouch

Mid-axillary line, ~8th–11th ribs · indicator cephalad · liver as the window

The hepatorenal recess (Morrison's pouch) between the liver and right kidney is the most dependent space in the supine trauma patient and the single most sensitive window. Fan through the whole interface, and don't stop there — also check the subphrenic space (above the liver) and the caudal liver tip.

Positive: an anechoic stripe in Morrison's pouch, at the liver tip, or above the diaphragm.

LUQ — perisplenic

Posterior axillary line, higher and more posterior than you expect · "knuckles to the bed"

The LUQ view is higher, deeper, and further back than the RUQ. Unlike the RUQ, fluid collects above the spleen (subphrenic) first, because the splenorenal ligament tethers the spleen to the kidney — so look in the subphrenic space and the splenorenal recess.

Positive: anechoic fluid above the spleen (subphrenic) or in the splenorenal interface.

Suprapubic — pelvis

Just above the pubic symphysis, sagittal and transverse · bladder as the window

Fan through the retrovesical space (behind the bladder) and, in women, the rectouterine pouch (of Douglas). A full bladder improves the window; fan fully left and right along the bladder's lateral borders.

Caveat: a small amount of physiologic pelvic fluid can be normal in women. Interpret in context and correlate with the other windows.

Subxiphoid — pericardium

Flat under the costal arch, indicator to the patient's left · liver as the window

Look for an anechoic stripe within the pericardium and for signs of tamponade (RV diastolic collapse). If the subxiphoid window fails — common in trauma with abdominal tenderness — substitute a parasternal or apical cardiac view.

The "extended" part — thorax

Anterior chest for pneumothorax · posterolateral bases for hemothorax

Over the anterior chest, absent lung sliding raises pneumothorax, confirmed by a lung point (see Lung, No. 011). At the posterolateral bases, look for anechoic fluid above the diaphragm and the spine sign — hemothorax.

Calling it

Free fluid drives the decision
WindowPositive findingMeans
RUQAnechoic stripe in Morrison's pouch / subphrenic / liver tipFree intraperitoneal fluid — most sensitive window
LUQFluid above the spleen or in the splenorenal recessFree intraperitoneal fluid; check subphrenic first
SuprapubicFluid retrovesical or in the pouch of DouglasFree pelvic fluid (trace can be physiologic in women)
SubxiphoidPericardial stripe ± RV diastolic collapsePericardial effusion / tamponade
Anterior thoraxAbsent sliding + lung pointPneumothorax
Thoracic baseAnechoic fluid above the diaphragm, spine signHemothorax

Bottom line: positive FAST + hemodynamically unstable = laparotomy. Positive FAST + stable = CT. Negative FAST never rules out injury — repeat it and correlate.

Pearls & pitfalls

Where this scan goes wrong
Pearl

Start in the RUQ

It's the most sensitive window for free fluid and often positive first. In a crashing trauma patient with limited time, the RUQ and subxiphoid views give the most decision-changing information fastest.

Pitfall

LUQ scanned too low and too anterior

The classic miss: the LUQ window is higher and more posterior than the RUQ, and fluid pools above the spleen, not below it. Put your knuckles on the bed and aim through the flank.

Pitfall

One negative scan = falsely reassured

Early or slow bleeding can produce a negative FAST that turns positive minutes later. Serial exams and a low threshold for CT (in the stable patient) catch what the first scan missed.

Pearl

Perinephric fat mimics fluid

A hypoechoic band of perinephric fat can fake a positive Morrison's. True free fluid is sharply anechoic and tracks into recesses; fat is more uniform and symmetric — compare sides.

Pitfall

Fluid is not always blood

Ascites, a ruptured cyst, urine, and prior peritoneal fluid all look identical to hemoperitoneum. The scan finds fluid; the clinical picture names it.

Pearl

Don't forget the pericardium

Penetrating "box" wounds kill through tamponade. The subxiphoid view is part of the exam, not an optional extra — and a parasternal view rescues it when the belly is too tender.

Sample Epic documentation

Copy · edit · attest

A starting template for a POCUS procedure note. Fields in blue are wildcards to complete. Build it as a SmartPhrase, then edit every field to match the actual study.

.pocusEFAST
POINT-OF-CARE ULTRASOUND: eFAST EXAM

Indication: [***] blunt/penetrating trauma, hypotension
Exam type: Focused / limited, bedside
Operator: @ME@   Interpretation: independent, real-time
Probe: curvilinear (abdominal) and linear (thoracic)
Consent: emergent, not obtained / [***]

VIEWS AND FINDINGS
- RUQ (hepatorenal / Morrison's pouch, subphrenic, liver tip):
    {no free fluid : free fluid present [***]}
- LUQ (perisplenic / subphrenic, splenorenal):
    {no free fluid : free fluid present [***]}
- Suprapubic (retrovesical / pelvis, sagittal + transverse):
    {no free fluid : free fluid present [***]}
- Subxiphoid / cardiac (pericardium):
    {no effusion : effusion, no tamponade physiology : effusion with RV diastolic collapse}
- Right anterior thorax: lung sliding {present : absent, lung point seen}
- Left anterior thorax: lung sliding {present : absent, lung point seen}
- Thoracic bases: {no fluid above diaphragm : hemothorax present [side ***]}

IMAGE QUALITY: adequate / limited by [***]
Images saved and archived to [PACS / Qpath / ***].

IMPRESSION: {Negative eFAST : Positive eFAST for [***]}.
Findings correlated with clinical picture; [***] plan.

I personally performed and interpreted this study in real time.
Electronically signed: @ME@  @TD@ @NOW@

Sample template only — not a validated institutional SmartPhrase. Verify wording, image-archival, and attestation requirements against your department's POCUS credentialing, coding, and compliance policies before clinical use. Documentation supports, but does not replace, the medical record and QA workflow.

PRN Education · POCUS Series

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