AN INNOVATIVE SYSTEM BASED ON BIOIMPEDANCE MEASUREMENTS TO DEFINE THE BLADDER VOLUME

Objectives: Alteration of the bladder sense of fullness due to spinal cord injury or radical cystectomy leads to the inability to plan micturition timing. The development of a system for the fullness detection would be highly desirable and would enable autonomous and spontaneous management of micturition by the patient. Here the design of an innovative system of bladder volume monitoring based on bioimpedance measurements is presented. Methods: Bioimpedance measurements are performed on ex-vivo bladder tissue using traditional ECG sensors. Two couples of electrodes in different arrangements were applied on the bladder walls to detect degree of filling by 50ml step, from 0ml to 300ml. The bioimpedance values are obtained for frequencies ranging from 1 kHz to 2 MHz. Moreover, different compositions of artificial urine were tested, by varying relevant ions concentration. Results: The impedance variations were recorded around 20ohm in average from empty to full status. However, the impedance variation was dependent to ion concentration in urine. Discussion: The experiment shows the feasibility of this approach and the need to find the sensors arrangement able to normalize measurements with respect to urine composition. Conclusions: A novel system to detect the bladder filling based on bioimpedence measures is reported. This approach could be feasible both in presence of natural or artificial/reconstructed bladder. Future work will target accurate volume estimation independently on urine composition, as well as combination with other sensing strategies. Acknowledgements: The authors acknowledge INAIL (Istituto Nazionale Assicurazioni Infortuni sul Lavoro) for providing their collaboration within the BioSUP project.