Real-Time Digital Monitoring of Continuous Bladder Irrigation: Clinical Evaluation of a Sensor-Based System for Hematuria and Catheter-Associated Events

Maximilian Glienke^1*Antonia Krumnau¹Anja Reichelt¹Gerd Reis²Christof Steiner³Philippe Fabian Pohlmann¹Franz Dressler⁴Christian Gratzke¹Arkadiusz Miernik¹Dominik Stefan Schöb¹

• ¹Department of Urology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
• ²German Research Center for Artificial Intelligence, Kaiserslautern,, Germany
• ³Digital Biomedical Imaging Systems AG, Pforzheim, Germany
• ⁴Department of Pathology, Faculty of Medicine, Charité – Universitätsmedizin Berlin, Berlin, Germany

Introduction: Continuous bladder irrigation (CBI) is commonly applied after transurethral resection of the prostate (TURP) or bladder tumor (TURBT) to prevent clot formation and maintain catheter patency. Despite its widespread use, the monitoring of CBI remains largely manual and subjective, relying on intermittent visual inspection of outflow characteristics. This approach is labor-intensive, prone to inter-observer variability, and can delay recognition of complications such as active bleeding, catheter obstruction, or bladder overdistension. We developed VisIMon, a digital monitoring system that enables continuous, sensor-based surveillance of CBI parameters including hemoglobin (Hb) concentration, inflow/outflow volumes, and flow disturbances. Methods: In this prospective feasibility study, 20 patients undergoing CBI after transurethral surgery were monitored with the VisIMon system for approximately four hours postoperatively. The system continuously recorded Hb concentration in the outflow via an optical sensor and tracked fluid dynamics using weight-based measurements. Manual reference data were collected every 20 minutes using a graduated measuring beaker and a digital scale. Blood gas analysis (BGA) was performed at the clinician's discretion in cases of suspected bleeding. All data were synchronized and visualized for graphical analysis. Results: The system operated reliably in all patients without technical failure or adverse events. The mean deviation between VisIMon-based and manually measured outflow volumes was −16 mL (range: −84 to + 73 mL), indicating acceptable accuracy. Hb trends recorded by the sensor corresponded qualitatively with available BGA data. The system detected clinically relevant flow irregularities— such as drainage interruptions and air bubbles - which were confirmed during bedside assessments. Patients tolerated the system well, and staff reported high usability and value in the graphical displays of real-time irrigation dynamics. Conclusion: The VisIMon system enabled continuous, objective monitoring of bladder irrigation in postoperative urological care. It demonstrated feasibility, accuracy, and user acceptance in a clinical setting and offers a promising tool for improving patient safety and workflow efficiency. Further validation in larger studies is warranted to assess its long-term impact and potential integration into closed-loop irrigation systems.