Noninvasive Optical Monitoring of Bladder Filling to Capacity Using a Wireless Near Infrared Spectroscopy Device

Abstract

Lack of bladder fullness sensation is an issue that arises in different neurogenic conditions and in addition to influencing patients' quality of life, can result in serious kidney damage. We describe a wireless wearable sensor for detecting bladder fullness using near infrared spectroscopy (NIRS). The sensor has been tested in vitro and in vivo to verify its feasibility and is shown to be capable of detecting changes in bladder content noninvasively.

Near-Infrared Spectroscopic Screening for Bladder Disease in Africa: Training Rural Clinic Staff to Collect Data of Diagnostic Quality

“…The device is encased in a plastic housing, weighs 58 gm, and has a sufficiently small form factor to not be a burden for the wearer. The full specifications and field trials to optimize photon penetration and confirm diagnostic accuracy have been described previously [18,19,24]; elements of the system are illustrated in Figure 1. time.…”

The evolution of near infrared spectroscopy in urology

“…Prior literature provides reports from individual animal and human studies, reviews of applications of NIRS in the field of urology [72,79,82,125], and descriptions of the development of dedicated instruments for bladder studies and recent introduction of wireless devices [76,86,99]. Urologic conditions studied include testicular hypo-perfusion, erectile dysfunction, renal hypoxia, skeletal muscle metabolism in patients with end stage renal disease, and the toxic effects of renal contrast media.…”

“…While this wavelength is usually avoided during bladder NIRS so that physiologic changes in the anterior bladder wall can be monitored without confounding absorption by the urine in the bladder, this wavelength has specific relevance to us as a means of monitoring change in bladder size in real time. This can be achieved by detecting altered attenuation at 975 nm as the bladder enters the field of view of a NIRS device placed on the abdomen so that it can monitor when the volume of urine in the bladder reaches capacity [99]. The software algorithms based on modification of the Lambert-Beer law continue to be utilized with custom refinements for some display requirements, including for fNIRS [32,42].…”

“…We have reported trials of a prototype device that incorporates a 975 nm NIR light source [99]. As water has an absorption peak at 975 nm, this device can be used to detect water content in the bladder and to differentiate between an empty bladder, one with low volume, and a full bladder.…”

“…The evolution of wireless NIRS devices and the related computer aided graphics and algorithms demonstrates innovation and clinician/researcher collaboration [64,76,99]. Miniature self-contained de-vices with LEDs and SRS capacity make non-invasive transcutaneous bladder monitoring straightforward and an attractive option for clinicians and their patients, including, children, the elderly and those with special needs (e.g.…”