Authors: Liu H et al.
Anesthesiology, February 23, 2026, 10.1097/ALN.0000000000006005
This prospective observational study evaluated whether different ultrasonographic measurement planes provide different estimates of gastric volume when performing preoperative gastric ultrasound. Gastric ultrasonography is increasingly used to assess aspiration risk before anesthesia, particularly in situations where fasting status is uncertain. However, different scanning planes may produce different measurements of the gastric antrum, raising concerns about which measurement best reflects true gastric volume.
The investigators focused on two commonly used ultrasound planes for evaluating the gastric antrum: the abdominal aorta (AA) plane and the inferior vena cava (IVC) plane. The primary objective was to determine which plane most accurately reflects actual gastric volume.
A total of 196 healthy volunteers were enrolled. Each participant first underwent gastric ultrasound after fasting, representing a low gastric volume state. Ultrasound measurements were obtained at both the abdominal aorta and inferior vena cava planes.
Participants then ingested apple juice at a standardized dose of 2.3 ml/kg body weight to simulate a higher gastric volume state. Gastric ultrasonography was repeated using the same two planes.
Predicted gastric volume was calculated using established ultrasound prediction formulas. The predicted ingested volume was derived by subtracting baseline predicted gastric volume from predicted gastric volume after ingestion. This value was then compared with the actual ingested volume to assess measurement accuracy.
The investigators found that measurements obtained at the AA plane and IVC plane differed significantly in both fasting and post-ingestion states. These differences indicate that measurement plane selection can substantially affect estimated gastric volume.
Among the different approaches evaluated, the plane producing the higher gastric volume measurement demonstrated the best agreement with the actual ingested volume. This method had the smallest measurement bias, approximately −4.27 ml, and did not differ significantly from the true ingested volume.
In contrast, relying exclusively on either the AA plane or the IVC plane alone produced greater discrepancies between predicted and actual gastric volumes.
The study also examined the ability of different measurement approaches to detect high aspiration risk. Using the higher-measured gastric volume plane improved the accuracy of identifying patients with larger gastric volumes that could increase aspiration risk.
The authors conclude that significant variability exists between ultrasound measurement planes during gastric volume assessment. When applying current gastric ultrasound predictive models, selecting the plane that yields the higher gastric volume measurement appears to produce more accurate estimates.
These findings suggest that clinicians performing gastric ultrasound should be aware of measurement plane variability and may improve accuracy by comparing multiple planes rather than relying on a single standard view.
What You Should Know
Gastric ultrasonography is increasingly used to estimate gastric volume and assess aspiration risk before anesthesia.
Measurements obtained at different ultrasound planes can produce significantly different gastric volume estimates.
This study found that the measurement plane producing the higher gastric volume most closely matched actual ingested volume.
Using multiple ultrasound planes may improve the accuracy of aspiration risk assessment.
Key Points
Prospective observational study including 196 volunteers.
Gastric ultrasound measurements were obtained at both abdominal aorta and inferior vena cava planes.
Significant differences were observed between measurement planes in both fasting and post-ingestion states.
The higher-measured gastric volume plane showed the best agreement with actual ingested volume.
Measurement plane selection may significantly influence gastric volume prediction and aspiration risk assessment.
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