Successful sonographic visualisation of the abdominal aorta differs significantly among a diverse group of credentialed emergency department providers

Background: The aims of this study were to examine the association between emergency department (ED) providers' experience with bedside ultrasound after achieving credentialing for abdominal aortic aneurysm (AAA) sonography, and their successful visualisation rate of the abdominal aorta among consecutive patients who presented asymptomatically but with risk factors for AAA. Methods: Study coordinators enrolled asymptomatic men >50 years presenting to a single ED with AAA risk factors. One of 20 AAA credentialed ED sonographers screened each subject for AAA. Screening forms and ultrasound images were reviewed for quality assurance. Multivariate logistic regression was used to estimate OR of visualisation and correct measurement among providers with varying experience, adjusted for bowel gas and body mass index (BMI). Results: During the 12 week enrolment, 278 patients were eligible and 196 (70%) enrolled. ED sonographers accurately visualised the entire abdominal aorta of 140 subjects (71.4%), did not completely visualise 40 (20.4%) and incorrectly measured 16 (8.2%). After controlling for bowel gas and BMI, providers with <1 year of experience (OR 6.7, 95% CI 2.0 to 22.2) and with 1-3 years experience post credentialing for AAA (OR 9.6, 95% CI 2.2 to 43.2) were significantly less likely to visualise and accurately measure the aorta compared to providers with >3 years experience. Conclusion: AAA sonography performance varied markedly among a diverse group of already credential ED sonographers. The most experienced providers demonstrated best performance. The present results suggest that some providers might require >25 proctored scans to ensure competency and training, and training on technically difficult patients should be part of the credentialing process.