Bladder volume estimation in the elderly using a portable ultrasound-based measurement device

We assessed the accuracy and ease of use of the BladderScan (BVI 2000) portable ultrasound-based bladder volume measurement device in a geriatric outpatient population. The Geriatric Continence Clinic nurse and physician each made 73 measurements on 36 subjects. Although the correlation coefficients between the true and ultrasound measurements were highly significant the mean differences were significantly different from zero. We suggest that, rather than considering the correlation coefficient, the accuracy required of the device should be described by a function of estimated versus true bladder volume. This function should vary depending on each particular decision-making process in which the estimate of volume is to be used. This instrument automatically estimates bladder volume once the user has completed the image creation and selection part of the process. The users in this study had difficulties with this imaging process. Possible ways in which the device's automated signal processing and volume calculation algorithms could be improved became evident during this study and are discussed.