Learning Curve of Bedside Ultrasound of the Gallbladder

Existing guidelines for the number of ultrasounds required before clinical competency are based not on scientific study but on consensus opinion. The objective of this study was to describe the learning curve of limited right upper quadrant ultrasound. This was a prospective descriptive study. Ultrasounds collected over 1 year were reviewed for interpretive and technical errors. Possible errors during bedside ultrasound of the gallbladder include incorrect interpretation, incomplete image acquisition, and improper or poor imaging techniques resulting in poor image quality. The ultrasound image quality was rated on a 4-point scale, with 1 = barely interpretable and 4 = excellent image quality. Required images were rated on an additional 4-point scale, with 4 = all required images were included and 1 = minimal images were recorded. There were 352 patients enrolled by 42 emergency physicians (35 residents and 7 attendings). Gallstones were identified in 13.9% of the patients, and 4.3% of the ultrasounds were indeterminate. Interpretive and technical error rates decreased as the clinician gained experience. The number of poor quality ultrasounds decreased after an average of seven ultrasounds. Inclusion of all required images increased after 25 ultrasounds. Sonographers who had performed over 25 ultrasounds showed excellent agreement with the expert over-read, with only two disagreements, both from a single individual. It was concluded that clinicians are clinically competent after performing 25 ultrasounds of the gallbladder.