A concept for wearable long-term urinary bladder monitoring with ultrasound. Feasibility study

Urinary incontinence as a result of neurological or age-related diseases is a very disturbing problem concerning a significant percentage of the population. People afflicted with this disorder cannot control the arbitrary filling of the urinary bladder. The most widespread solution is catheterization, which is neither pleasant nor harmless. A device monitoring bladder fill level could remind patients about the need for a draining, grant them greater comfort and save their health and costs. We developed a concept of a wearable ultrasound system for continuous monitoring. Our system does not use ultrasound gel, but implements a dry coupling. This is why in contrary to existing ready-to-use systems, it can work automatically and continuously. For the duration of the cyclic measurements the skin adheres to the transducer and transmission becomes high enough to make the estimation of the bladder fill level with ultrasound possible. We present the results of a feasibility study. We empirically examined the power transmission as a function of adhering force for different skin samples and compared it with values achieved using ultrasound gel. For this purpose we constructed ultrasound transmitting and receiving hardware and a setup enabling to set and measure the applied force. Based on further calculations we confirmed that the level of the received reflected signal is high enough to successfully estimate the amount of urine in the bladder.