A Prospective Evaluation of Emergency Department Bedside Ultrasonography for the Detection of Acute Cholecystitis
Presented at the Western Regional Research Forum, Plenary Session, January 2009, Park City, UT; at the American Institute of Ultrasound in Medicine, April 2009, New York, NY; and as a poster at the Society of Academic Emergency Medicine, May 2009, New Orleans, LA.
Received 24 June 2009; received in revised form 25 October 2009 and 20 December 2009; accepted 12 January 2010. published online 08 February 2010. Corrected Proof
Study objective
We assess the diagnostic accuracy of emergency physician–performed bedside ultrasonography and radiology ultrasonography for the detection of cholecystitis, as determined by surgical pathology.
Methods
We conducted a prospective, observational study on a convenience sample of emergency department (ED) patients presenting with suspected cholecystitis from May 2006 to February 2008. Bedside gallbladder ultrasonography was performed by emergency medicine residents and attending physicians at an academic institution. Emergency physicians assessed for gallstones, a sonographic Murphy's sign, gallbladder wall thickness, and pericholecystic fluid, and the findings were recorded before formal imaging. The test characteristics of bedside and radiology ultrasonography were determined by comparing their respective results to pathology reports and clinical follow-up at 2 weeks.
Results
Of the 193 patients enrolled, 189 were evaluated by bedside ultrasonography. Forty-three emergency physicians conducted the ultrasonography, and each physician performed a median of 2 tests. After the bedside ultrasonography, 125 patients received additional radiology ultrasonography. Twenty-six patients underwent cholecystectomy, 23 had pathology-confirmed cholecystitis, and 163 were discharged home to follow-up. Twenty-five were excluded (23 lost to follow-up and 2 unavailable pathology). The test characteristics of bedside ultrasonography were sensitivity 87% (95% confidence interval [CI] 66% to 97%), specificity 82% (95% CI 74% to 88%), positive likelihood ratio 4.7 (95% CI 3.2 to 6.9), negative likelihood ratio 0.16 (95% CI 0.06 to 0.46), positive predictive value 44% (95% CI 29% to 59%), and negative predictive value 97% (95% CI 93% to 99%). The test characteristics of radiology ultrasonography were sensitivity 83% (95% CI 61% to 95%), specificity 86% (95% CI 77% to 92%), positive likelihood ratio 5.7 (95% CI 3.3 to 9.8), negative likelihood ratio 0.20 (95% CI 0.08 to 0.50), positive predictive value 59% (95% CI 41% to 76%), and negative predictive value 95% (95% CI 88% to 99%).
Conclusion
The test characteristics of emergency physician–performed bedside ultrasonography for the detection of acute cholecystitis are similar to the test characteristics of radiology ultrasonography. Patients with a negative ED bedside ultrasonography result are unlikely to require cholecystectomy or admission for cholecystitis within 2 weeks of their initial presentation.
Department of Emergency Medicine, University of California, Irvine, Orange, CA
Address for correspondence: Shane M Summers, MD, RDMS, Brooke Army Medical Center Department of Emergency Medicine, 3851 Roger Brooke Dr, Ft Sam Houston, TX 78234; 210-887-6156 or 210-916-1006, fax 210-916-2265
Supervising editor: William R. Mower, MD, PhD
Author contributions: SMS drafted the article. SMS, MDM, and JCF contributed to article revision. WS, SSC, and JCF conceived the study. WS and SSC designed the study. WS and OA prepared the IRB. S Lanham collected data, surveyed the electronic medical record for pathology reports, and performed telephone follow-ups. S Lanham and OA assisted with literature review. CA managed the data and performed the statistical analysis. S Lotfipour assisted with patient recruitment and supervised data collection. S Lotfipour and JCF supervised the conduct of the trial and provided quality control. SMS takes responsibility for the paper as a whole.
Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article that might create any potential conflict of interest. See the Manuscript Submission Agreement in this issue for examples of specific conflicts covered by this statement. JCF has been a consultant for Sonosite Corp (Bothell, WA) for ultrasound education. Sonostie was not involved in the study in any capacity. He received no royalties,sponsorship, or funding for this study.
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