Bladder Volume Measurement Using Portable Ultrasound Instrument in Spinal Cord Injury Patients

ABSTRACT

A noninvasive measurement of residual urine or bladder volume would reduce number of unnecessary catheterizations and be useful for an intermittent catheterization program in the management of neurogenic bladder. The purpose of this study is to evaluate a portable ultrasound instrument for the measurement of bladder volume and to assess the effect of several factors such as trabeculation or soft tissue thickness on the accuracy of the measurements. Nine patients with neurogenic bladder dysfunction underwent 480 bladder volume measurements using a portable ultrasonographic device(BVI-2500 BladderScan) before 60 intermittent catheterizations. Ultrasonographic measurements of urine volume were compared with catheterized urine volumes. The mean difference was 46.42+/-39.15 cc and the mean percentage error was 23.32+/-19.31%. Mean differences of each bladder capacity were not affected by bladder capacity, and mean percentage errors tend to decrease as the bladder capacity increase. Bladder trabeculation and soft tissue thickness had no effect on the accuracy of the measurements. The ultrasonographic measurements detected the presence of residual urine volumes of > or =100 cc with a sensitivity of 81% and a specificity of 93%. The repeatability(Mean/SD) was 23%. The accuracy had no correlation with the frequency of scanning. We conclude that BVI-2500 bladder scan portable ultrasonographic device is a useful tool for the management of neurogenic bladder dysfunction in spinal cord injured people. Trabeculation and soft tissue thickness has no effect on the accuracy of the measurements.