Biliary ultrasonography for cholelithiasis: A retrospective analysis of the first two years of an emergency ultrasonography training program

Abstract

Study objectives: Traditional diagnostic evaluation for patients presenting to the emergency department (ED) with right upper quadrant (RUQ) pain involves an ultrasonography performed by a sonographer and interpreted by a radiologist, which can result in long delays, higher costs, and patient dissatisfaction. Emergency physicians performing the initial RUQ ultrasonography to investigate for cholelithiasis can potentially shorten this evaluation. Previous studies in the emergency medicine literature report the accuracy of emergency physicians performing RUQ ultrasonography but have relatively small sample sizes. The study objective is to analyze the accuracy of bedside RUQ ultrasonography for evaluation of cholelithiasis by emergency physicians. Methods: A retrospective study was conducted on patients presenting to the ED who received a focused RUQ ultrasonography performed by an emergency medicine resident or attending physician between July 2001 and November 2003 in our urban, university, Level I trauma center. Physicians performing bedside ultrasonography were given various lectures on abdominal ultrasonography, including hands-on practice with quality assurance follow-up of videotaped scans. Emergency ultrasonographic examinations were performed using a 3.5-Mhz microconvex probe. All scans included in this study were reviewed by the quality assurance committee consisting of an emergency ultrasonography fellowship–trained attending physician and an emergency ultrasonography fellow. The quality assurance committee was blinded to the findings of the radiology ultrasonographs. Emergency ultrasonographic findings were limited to the presence or absence of gallstones. Three sets of comparisons were made: (1) emergency ultrasonographic findings versus the ED quality assurance committee's findings; (2) emergency ultrasonographic findings versus the radiology ultrasonographic findings; and (3) ED quality assurance committee's findings versus the radiology ultrasonographic findings. Results: Of a total of 1,577 emergency RUQ ultrasonographs during the study period, a total of 1,191 scans met inclusion criteria. Three hundred eighty-six scans were excluded because of documentation errors and poor image quality. Overall, 411 (35%) patients were confirmed to have gallstones, and 780 (65%) were without gallstones. Emergency resident interpretation had an 88% sensitivity, 97% specificity, and 93% accuracy when compared when compared with the ED quality assurance committee's findings. Of the 1,191 patients in the study, 429 (36%) patients also had a radiology ultrasonograph. From these, 257 (60%) patients were confirmed to have gallstones, and 172 (40%)patients were without gallstones. Compared with a radiology ultrasonograph as the criterion standard, emergency resident interpretation had an 88% sensitivity, 87% specificity, and 88% accuracy. When comparing the ED quality assurance committee's findings of this same subset against the radiology ultrasonograph (the criterion standard), the ED quality assurance committee was found to have a 91% sensitivity, 91% specificity, and 91% accuracy. Conclusion: Emergency bedside RUQ ultrasonography is an effective method of diagnosing cholelithiasis. Emergency physicians with a moderate amount of training have a high sensitivity and specificity for diagnosing cholelithiasis compared with radiology-performed ultrasonography. Furthermore, we demonstrate that review of recorded ultrasonographs from the ED by a fellowship-trained quality assurance committee can increase the accuracy of diagnosing cholelithiasis and serve as an important educational tool. These data add to a growing support for the use of bedside ultrasonography in the ED.