SENS-U: validation of a wearable ultrasonic bladder monitor in children during urodynamic studies

Purpose Urinary incontinence is a common problem in school-age children. Because many children remain unaware of a full-bladder sensation, the SENS-U (TM) Bladder Sensor was developed. The SENS-U is a small, wearable ultrasound sensor, which is positioned on the lower abdomen using a skin-friendly adhesive. The sensor continuously estimates the bladder filling status and informs the user when it is time to go to the toilet. In this study, the clinical performance of the SENS-U is evaluated in children during (video) urodynamics. Material and methods In this study, 30 children (6e12 years) were included who were scheduled for a (video) urodynamic study. During urodynamics, the SENS-U determined the average anterioreposterior (A-P) bladder dimension (every 30 s) to estimate the filling status. The correlation between the average A-P bladder dimension and the infused volume is analyzed by Spearman's correlation. Results Thirty patients (boys/girls: 15/15; mean age: 7.9 +/- 1.4 years) were included, in whom the SENS-U detected the full bladder before voiding in 90% of the patients (27/30). In the other patients, the bladder was outside the detection area due to either erroneous sensor placement (n = 1) or an (relative) obese abdomen in the upright position (n = 2). There was a strong correlation (median r(s) = 0.94) between the average A-P bladder dimension and the infused volume. The detectable maximum bladder volume ranged between 71 and 463 ml. Conclusion The SENS-U is able to detect a full bladder with a success rate of 90%. When excluding erroneous data due to sensor misplacement or an (relative) obese abdomen, the detection rate may even be higher. Future research will focus on investigating the effect of theSENS-U in incontinence training.