Abstract / Summary
The measured gallbladder contractile response can vary with the test meal used to stimulate gallbladder emptying. However, the traditional fatty-meal test using fried eggs is limited by inconsistent fat content and variable gastric emptying. This pilot study aimed to develop a new Ensure-based ultrasound protocol for gallbladder function assessment using a commercially available enteral nutrition formula (Ensure) and to compare the gallbladder contractile responses induced by Ensure with those induced by the traditional fried-egg method. We conducted a two-phase prospective pilot study in healthy volunteers to develop and preliminarily evaluate an Ensure-based protocol. Gallbladder volume was measured using serial abdominal ultrasound scans after ingestion of the test meals. Gallbladder ejection fraction (GBEF) was then calculated as the percentage reduction in volume from the fasting state to postprandial intervals. Phase 1 compared three Ensure-based meals containing 8, 12, and 16 g of fat in 8 subjects to select a practical dose and measurement schedule. Phase 2 compared the Ensure-based protocol against the traditional fried egg method in 10 subjects. The 12-g Ensure dose induced stronger contractions than 8-g (P = 0.037) and demonstrated better tolerability than the 16-g dose. Peak contractions were observed primarily between 30 and 60 min, supporting the selection of 30, 45, and 60 min as practical measurement time points. In a self-controlled comparison involving 10 healthy volunteers, Ensure produced a significantly higher GBEFmax than fried eggs (76.30% ± 10.43% vs. 62.99% ± 7.15%, P = 0.003). In this study, an Ensure-based meal containing 12 g of fat provided a standardized and well-tolerated stimulus for gallbladder contraction and resulted in a higher GBEFmax than the traditional fried-egg meal. These findings support further clinical validation of this protocol and the establishment of appropriate reference values. Not applicable. Not applicable.