EM SAQs · POCUS — FAST and E-FAST
FAST disposition matrix in blunt trauma
ACEM-style SAQ on FAST technique, accuracy, and disposition.
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Four views: hepatorenal, splenorenal, pelvic (pouch of Douglas/rectovesical; decompress bladder first), subxiphoid pericardium — extended with bilateral anterior chest and IVC assessment, imaged in a fixed order so no window is missed. Accuracy: for abdominal trauma POCS sensitivity 0.68 with specificity 0.95; for chest injuries 0.96 and 0.99 — rule-in, not rule-out; a single negative misses injuries at 28% prevalence.[2]
Disposition matrix — confirm thresholds against local trauma protocol:
- Positive + unstable → theatre + MTP + TXA (not CT)
- Positive + stable → CT for organ grading
- Negative + unstable → not clearance; seek pelvic/retroperitoneal/thoracic sources; repeat FAST; theatre/angio if not stabilising
- Negative + stable → observe, serial exam/FAST, CT if mechanism/exam warrants
False negatives: retroperitoneal bleed; pelvic-only bleed; hollow viscus early; early scan before fluid accumulates; obesity/subcut emphysema technical failure — these explain missed injuries at prevalence in the held review.[2]
References2ShowHide
- [1]Nishijima DK, Simel DL, Wisner DH, Holmes JF. Does this adult patient have a blunt intra-abdominal injury? JAMA, 2012.PMID 22496266
- [2]Stengel D, et al. Point-of-care ultrasonography for diagnosing thoracoabdominal injuries in patients with blunt trauma. Cochrane Database of Systematic Reviews, 2018.PMID 30548249