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Abstract
Background and aims Ultrasound estimation of gastric volume is useful preoperatively for identifying those at increased risk of aspiration; however, studies to date have excluded subjects with prior gastric surgeries. We aimed to assess the performance of the current equation used in non-pregnant adults for patients who had undergone gastric sleeve and develop a new equation for this population if necessary. Secondarily, we determined if a 2-hour fast from clear fluids is sufficient to empty the stomach in this population.
Methods 37 subjects who had undergone a gastric sleeve in the last 10 years were randomly assigned to drink 100, 200 or 300 mL of water after fasting 8 hours from solids and 2 hours from clear fluids. Pre-drink and 0, 30, 60, 90 and 120 min post-drink scans measured antral grade and cross-sectional area. Subjects participated in up to three study visits drinking different volumes.
Results The existing equation was statistically suboptimal. A new equation was created with variables identified by LASSO regression (Volume (mL)=15.5×CSA (cm2)−0.28×Weight (kg)−0.75×Height (cm)+97.9) with a mean bias of <1 mL (95% limits of agreement −51.2 to 51.2 mL). After 120 min, 93.2% of post-drink scans were grade 0, and all had a calculated volume <1.5 mL/kg.
Conclusions The existing equation is likely still best suited for clinical use; however, the equation proposed here has superior accuracy in patients with prior gastric sleeve. A 2-hour fast from clear fluids is sufficient in this population.
- Ultrasonography
- TECHNOLOGY
- Anesthesia
- General
Data availability statement
All data relevant to the study are included in the article or uploaded as supplementary information.
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Data availability statement
All data relevant to the study are included in the article or uploaded as supplementary information.
Footnotes
Contributors JRW contributed to the study design and registration, subject recruitment, ultrasound scanning, manuscript preparation and data analysis. JCM contributed to the consenting subjects, data collection and manuscript editing. YK contributed to the subject recruitment, data collection, data analysis and manuscript editing. DGS contributed to the ultrasound scanning and manuscript editing. MP contributed to the consenting subjects, data collection and manuscript editing. XA contributed to the data analysis and manuscript editing. SAG contributed to the study design, ultrasound scanning supervision and manuscript editing. ASD contributed to the study design, ultrasound scanning supervision, manuscript editing and project guarantor.
Funding Institutional funding from the Department of Anesthesiology, University of North Carolina at Chapel Hill. The funder did not influence the results/outcomes of the study despite author affiliations with the funder.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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