A prospective evaluation of emergency department bedside ultrasonography for the detection of acute cholecystitis.
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%).


CONCLUSIONS
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, USA. shanemsummers@yahoo.com
Shane M
SM
Summers
William
W
Scruggs
Michael D
MD
Menchine
Shadi
S
Lahham
Craig
C
Anderson
Omar
O
Amr
Shahram
S
Lotfipour
Seric S
SS
Cusick
J Christian
JC
Fox
D000328:Adult; D041881:Cholecystitis, Acute / Q000000981:diagnostic imaging* / Q000473:pathology; D016001:Confidence Intervals; D004636:Emergency Service, Hospital; D005260:Female; D005704:Gallbladder / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D016013:Likelihood Functions; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D019095:Point-of-Care Systems / Q000592:standards; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014463:Ultrasonography