Efficacy of the bile leak test using contrast-enhanced intraoperative ultrasonic cholangiography in liver resection: a study protocol for a non-randomised, prospective, off-label, single-arm trial.

introductionBile leak is still a major complication after liver resection to be improved. To intraoperatively detect this adverse complication, leak test is commonly performed after hepatic resection. However, by the conventional leak test, it is often difficult to know whether the test reagent reaches to intrahepatic bile duct near cut surface of liver with adequate volume and pressure to identify the existence of bile leak. Thus, in order to perform leak test more accurately, this study aims to evaluate the efficacy and safety of the leak test using contrast-enhanced intraoperative ultrasonic cholangiography (CE-IOUSC), which was reported by our group as a procedure for detection of bile duct. METHODS AND ANALYSIS: The current study is a non-randomised, prospective, off-label, single-arm clinical trial for patients who undergo liver resection. A total of 100 patients will be enrolled. After completion of liver resection, the leak test is performed with CE-IOUSC using Sonazoid as a contrast agent to visualise dye injection into the intrahepatic bile duct. The primary endpoint is the success of the leak test, defined as clear visualisation of intrahepatic bile duct around cut surface by ultrasonography that indicates enough volume of dye injection. Secondary endpoints are postoperative bile leak and all adverse events related to CE-IOUSC. The findings obtained through this study will establish this procedure to assist surgeons for adequately performing the leak test, precisely detecting intraoperative biliary leak strictly and reducing postoperative bile leak. ETHICS AND DISSEMINATION: The protocol is approved by Institutional Review Boards of Kobe University Hospital (No.290069). Our findings will be widely disseminated through conference presentations and peer-reviewed publications. TRIAL REGISTRATION NUMBER: UMIN000031236 and jRCTs051180027.