Wearable Device Continuously Monitors Bladder Health

By Dr. Noopur JainReviewed by Susha Cheriyedath, M.Sc.Sep 26 2024

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.

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 comprehensive, multi-faceted approach, focusing on the design, fabrication, and testing of the ultrasonic transducers alongside the integration of control electronics and wireless communication systems.

The ultrasonic transducers were designed to be flexible and air-backed, enabling them to conform to the contours of the human body for optimal performance. Operating in A-mode, the transducers used low-power receiver circuitry to capture echo signals from the bladder walls. A spherical fitting algorithm was implemented to accurately estimate bladder volume based on distance measurements between the anterior and posterior walls of the bladder.

The hardware modeling and simulation for the UBVM device were carried out using LTSpice, utilizing Leach’s equivalent circuit model to represent the ultrasonic transducers in their air-backed configuration. An independent voltage source was employed to excite the transducers, while two ideal operational amplifiers and a comparator were integrated into the design to model the receiving circuitry. To improve measurement accuracy, the aspect ratio of the transducers was carefully selected to be less than 0.2, isolating the thickness-mode resonance.

In vitro testing involved using stainless-steel reflectors and round-bottom flasks filled with varying volumes of water to assess the device's performance. Pulse-echo experiments were performed at multiple frequencies to evaluate the efficiency of the electronics and firmware.

For in vivo validation, the UBVM device was tested on five healthy volunteers after receiving ethical approval from the Koç University Ethics Committee. Participants were screened for eligibility based on their medical history and BMI, ensuring no history of urinary surgeries or electronic implants.

Results and Discussion

The evaluation of the UBVM device demonstrated its ability to accurately measure bladder volume in real time, showing a strong correlation with traditional ultrasound measurements. During in vivo trials with five healthy volunteers, the device successfully tracked the entire micturition cycle, continuously capturing bladder volume fluctuations as participants consumed water to promote bladder filling. This 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 comfortably conform to the body, making it easy to use during everyday activities. Participants reported a positive experience, appreciating its non-invasive nature and the convenience of wireless data transmission to mobile applications. This feature not only enhances user comfort but also enables real-time monitoring and feedback, empowering individuals to proactively manage their bladder health.

The findings suggest that the UBVM device offers significant advantages over conventional methods, particularly in its ability to provide continuous monitoring without the need for trained personnel. This innovation has the potential to improve the management of lower urinary tract dysfunctions, reducing the frequency of clinical visits and giving patients greater autonomy in managing their condition.

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