Utility of common bile duct measurement in ED point of care ultrasound: A prospective study

Background Measurement of the common bile duct (CBD) is considered a fundamental component of biliary point-of-care ultrasound (POCUS), but can be technically challenging. Objective The primary objective of this study was to determine whether CBD diameter contributes to the diagnosis of complicated biliary pathology in emergency department (ED) patients with normal laboratory values and no abnormal biliary POCUS findings aside from cholelithiasis. Methods We performed a prospective, observational study of adult ED patients undergoing POCUS of the right upper quadrant (RUQ) and serum laboratory studies for suspected biliary pathology. The primary outcome was complicated biliary pathology occurring in the setting of normal laboratory values and a POCUS demonstrating the absence of gallbladder wall thickening (GWT), pericholecystic fluid (PCF) and sonographic Murphy's sign (SMS). The association between CBD dilation and complicated biliary pathology was assessed using logistic regression to control for other factors, including laboratory findings, cholelithiasis and other sonographic abnormalities. Results A total of 158 patients were included in the study. 76 (48.1%) received non-biliary diagnoses and 82 (51.9%) were diagnosed with biliary pathology. Complicated biliary pathology was diagnosed in 39 patients. Sensitivity of CBD dilation for complicated biliary pathology was 23.7% and specificity was 77.9%. Conclusion Of patients diagnosed with biliary pathology, none had isolated CBD dilatation. In the absence of abnormal laboratory values and GWT, PCF or SMS on POCUS, obtaining a CBD measurement is unlikely to contribute to the evaluation of this patient population.