In a recent article published in the journal Nature Communications, researchers presented a novel integrated wearable ultrasonic bladder volume monitoring (UBVM) device that offers a non-invasive, accurate, and continuous solution for bladder volume assessment. The device is designed to be flexible and wireless, making it suitable for real-life applications outside clinical settings.
Study: An integrated and flexible ultrasonic device for continuous bladder volume monitoring. Image Credit: iWissawa/Shutterstock.com
Background
Bladder volume measurement is crucial for the early detection and management of lower urinary tract dysfunctions (LUTD), which can significantly impact the quality of life for millions of individuals. Current gold standard techniques for bladder volume measurement are invasive and often impractical for routine use. Alternative technologies, including electrical impedance analysis and near-infrared spectroscopy, have been explored.
However, these methods typically provide only coarse estimations of bladder volume and are prone to inaccuracies due to motion artifacts and urine-dependent properties. Recent advancements in wearable ultrasonic transducers have opened new avenues for continuous monitoring in healthcare.
Despite these advancements, many existing devices still rely on bulky electronics and wired connections, limiting their usability in everyday life. The authors aim to address these limitations by developing a UBVM device that integrates flexible ultrasonic transducers with miniaturized control electronics, enabling accurate and autonomous bladder volume monitoring.
The Current Study
The development of the UBVM device involved a multi-faceted approach, focusing on the design, fabrication, and testing of the ultrasonic transducers, as well as the integration of control electronics and wireless communication systems.
The ultrasonic transducers were designed to be flexible and air-backed, allowing them to adapt to the contours of the human body for optimal performance. The transducers operated in A-mode, utilizing a low-power receiver circuitry to capture echo signals from the bladder walls. The design incorporated a spherical fitting algorithm to estimate bladder volume accurately based on the distance measurements between the anterior and posterior walls of the bladder.
Modeling and simulation of the UBVM hardware were conducted using LTSpice, employing Leach’s equivalent circuit model to represent the ultrasonic transducers in an air-backed configuration. An independent voltage source was used to excite the transducers, while two ideal operational amplifiers and a comparator were integrated to model the receiving circuitry. The aspect ratio of the transducers was carefully selected to be less than 0.2 to isolate the thickness-mode resonance, enhancing measurement accuracy.
In vitro testing was performed using stainless-steel reflectors and round-bottom flasks filled with varying volumes of water to evaluate the device's performance. Pulse-echo experiments were conducted at multiple frequencies to assess the effectiveness of the electronics and firmware.
For in vivo validation, the UBVM device was tested on five healthy volunteers, following ethical approval from the Koç University Ethics Committee. Participants were screened for eligibility based on their medical history and BMI, ensuring no prior urinary surgeries or electronic implants.
Results and Discussion
The evaluation of the UBVM device revealed its capability to accurately measure bladder volume in real-time, demonstrating a strong correlation with traditional ultrasound measurements. During the in vivo trials involving five healthy volunteers, the device successfully captured the entire micturition cycle, providing continuous data on bladder volume fluctuations as participants ingested water to promote bladder filling. This feature highlights the device's effectiveness in monitoring bladder dynamics in a natural setting.
The integration of flexible ultrasonic transducers and miniaturized electronics allowed the UBVM device to conform comfortably to the body, facilitating ease of use during daily activities. Participants reported a positive experience with the device, emphasizing its non-invasive nature and the convenience of wireless data transmission to mobile applications. This capability not only enhances user comfort but also enables real-time monitoring and feedback, empowering individuals to manage their bladder health proactively.
The findings indicate that the UBVM device offers significant advantages over conventional methods, particularly in terms of continuous monitoring without the need for trained personnel. This innovation could lead to improved management of lower urinary tract dysfunctions, reducing the frequency of clinical visits and enhancing patient autonomy.
Conclusion
In conclusion, the integrated and flexible ultrasonic bladder volume monitoring device represents a significant advancement in the field of non-invasive medical diagnostics. By combining innovative design with practical functionality, the device offers a reliable solution for continuous bladder volume monitoring, addressing the limitations of traditional methods. The successful validation of the device in both in vitro and in vivo settings underscores its potential for real-world applications, particularly for individuals suffering from lower urinary tract dysfunctions.
As the demand for wearable health technologies continues to rise, the UBVM device stands out as a pioneering tool that could enhance patient care and improve health outcomes. Future research may focus on further refining the technology and exploring its applications in other areas of healthcare, ultimately contributing to a more comprehensive approach to patient monitoring and management.
Journal reference
Toymus A.T., Yener U.C., et al. (2024). An integrated and flexible ultrasonic device for continuous bladder volume monitoring. Nature Communications 15, 7216. DOI: 10.1038/s41467-024-50397-8, https://www.nature.com/articles/s41467-024-50397-8