Urinary incontinence is a common and debilitating problem for more than 40 million people worldwide. The current gold standard method of diagnosing incontinence involves cystometry and urodynamics: expensive, nonphysiological laboratory tests that do not always reproduce patient complaints. We are proposing feasibility testing of a bladder function monitoring system, the DynaSystem(tm), which will monitor bladder function continuously for up to 48 hours with the patient unencumbered by external catheters, much as a holler monitor does for the heart. The DynaSystem will consist of a control unit connected wirelessly to 2 probes, an intravesical one [the DynaSphere] and an intravaginal one [the DynaPessary(tm)]. The DynaSphere will monitor bladder pressure and volume, as well as urine temperature, conductivity, and pH. It will be based on technology developed for the ContiSphere(tm), a balloon continence device that is inserted intraurethrally and inflated with low density mineral oil using an insertion device. The insertion device is then removed and the balloon will float in the bladder without obstructing voiding. The DynaPessary will wirelessly monitor abdominal pressure as well as patient position and movement using an inclinometer and accelerometers. The balloon carrier is presently undergoing clinical testing and miniaturized transducers are available for all variables to be recorded, except for bladder volume. Therefore, in this Phase I feasibility testing proposal we concentrate on development and testing of an intravesical bladder volume sensor using an electrical conductance technique whose potential is demonstrated in pilot data. The work will be accomplished by the following Specific Aims:
Specific Aim 1 : Determine the combination of design parameters that best achieves acceptable accuracy and reproducibility of volume sensing using the conductance technique.
Specific Aim 2 : Perform sensitivity analysis on the volume measurements to determine sensitivity to changes in bladder and urine.
Specific Aim 3 : Prototype and test foldable models based on the best performing rigid probes. Device development will be performed at Dynaventions, Inc. Testing of the prototypes will be performed at Hines VA Hospital using bladders from pigs already being used in lACUC-approved studies. When bladder volume can be measured intravesically to acceptable standards using a foldable probe, we will be ready for Phase II development and testing.