Operator confidence correlates with more accurate abdominal ultrasounds by emergency medicine residents

The purpose of this study was to assess whether greater operator confidence correlates with more accurate focused abdominal ultrasounds (FAUS) by residents. This was a prospective study of novice residents performing FAUS in patients with abdominal pain. FAUS included focused assessment with sonography for trauma, gall bladder, renal, and aortic examinations. Residents answered the question, "How confident are you of your findings?" using a visual scale from 1 (doubtful) to 5 (certain). The results of the resident-performed FAUS were compared to subsequent criterion evaluations. Thirty-eight residents with an average experience of 27 (95% confidence interval [CI] 18-36) prior US examinations evaluated 504 patients. Greater operator confidence correlated with improved accuracy of FAUS (R(2) = 0.858, p = 0.0369). Sensitivity and specificity were 14% (95% CI 4-37 %) and 71% (95% CI 48-88 %) with a confidence level of 2/5 but 85% (95% CI 73-93 %) and 100% (95% CI 97-100 %) with a confidence level of 5/5. Greater operator confidence correlates with improved accuracy in FAUS. This should be considered in the development of training guidelines.