This is a focused secondary analysis of 65 gastric point-of-care ultrasound studies drawn from a previously published narrative review, classifying each by its purpose: foundational or validation work, clinical decision-impact studies, or population and intervention research.
The distribution is stark. Of 65 studies, 54 were population or intervention research and 9 were foundational or validation work. Only 2 were clinical decision-impact studies. Management change was reported or extractable in 8 studies and prespecified in only 3. Where it was reported, every one of those 8 found at least one actual management change, at rates ranging from 0.4% to 46%; the two dedicated clinical studies reported 5.0% and 18.9%. Changes included converting to rapid sequence induction, modifying the airway plan, postponing or cancelling, converting to local or regional anaesthesia, and both more and less conservative aspiration management. No study linked a management change to a patient-centred outcome.
This matters because gastric ultrasound is being adopted on the strength of a large literature that has mostly measured whether the technique can see stomach contents rather than whether seeing them helps. The technique is real and the images are reliable. What is missing is evidence that a scan-driven decision produces a better outcome than the fasting rule it overrides. Keep scanning where the answer would change your plan — an urgent case, a diabetic with gastroparesis, an incompletely fasted patient — and record the pre-scan plan alongside the post-scan one, because that record is the evidence the field lacks.
- Scan when the result would change your plan, not to document what you were going to do anyway.
- Record the pre-scan plan, the finding, and the post-scan decision — that triplet is what makes an audit useful.
- A reported management change rate of 0.4% to 46% across studies reflects patient selection, not technique quality.
- No study has yet linked a scan-driven decision to a patient outcome; do not claim aspiration prevention.
- Train on normal stomachs before relying on the scan in the patient who worries you.
The statistics, in plain English
That every study reporting management change found at least one is an artefact of reporting: studies where nothing changed had less reason to report it, so the true average change rate is almost certainly lower than the 0.4% to 46% range suggests. A validated technique and a useful technique are different claims requiring different studies, and this analysis shows the literature has almost entirely answered the first.
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