Emergency medicine resident performed bedside ultrasonography of the gallbladder in non-fasted healthy volunteers

Background: Gallbladder ultrasonography is a commonly performed test in the emergency department. It is unknown whether a non-fasting state alters the visualization of the gallbladder by emergency medicine (EM) residents.

Objectives: We conducted this study to determine whether EM residents are able to visualize the gallbladder in volunteers who have recently consumed a fatty meal.

Methods: This study used a prospective, single-blinded, randomized controlled design. Initial scans were performed on fasting volunteers. A fatty meal was then consumed. Thirty minutes after eating, a different resident, who was unaware of whether the volunteer had eaten or fasted, performed a second scan. To control for operator bias, 10% of subjects remained fasting between scans. Student's paired-samples t-test, Pearson's chi-squared, and McNemar test were determined as appropriate.

Results: A total of 92 scans from 46 volunteers were analyzed. EM residents were able to visualize the gallbladder in all 40 pre-prandial scans (100%) and all 40 post-prandial scans (100%). Gallbladder area as measured in the longitudinal axis decreased 20% from a mean baseline of 11.58 +/- 4.86 cm(2) (95% confidence interval [CI] 11.17-12.98) to 9.2 +/- 5.04 cm(2) (95% CI 7.74-10.66, p = 0.0009) after food intake. Total time to scan for the fasting volunteers (110.2 s, 95% CI 84.34-136) did not change significantly from non-fasting volunteers (129.7 s, 95% CI 110.29-149.01, p = 0.153).

Conclusions: EM residents are able to visualize the gallbladder in non-fasted healthy volunteers.