Neurogenic bladder monitoring using the cystomanometer and cystoelastometer

Patients with neurogenic bladder (NGB) require periodic urodynamics (UDS) to evaluate bladder function, which in turn helps guide management. At times, bladder decompensation or hydronephrosis may develop in patients between urodynamic testing intervals. Increased surveillance has improved outcomes in other chronic conditions (e.g., diabetes). Two novel devices, the cystomanometer (CM) and cystoelastometer (CEM), have been developed at the authors' institution to allow for home bladder pressure monitoring. The handheld CM can be attached to the end of any catheter and records the opening bladder pressure along with a time stamp. In addition, the CEM actively evacuates urine via a pump and records the urine volume evacuated. For safety, the pump slows and stops as it detects increasing resistance. Data are stored and transmitted wirelessly from both devices to a smartphone. A novel phone application stores, displays, and transmits data to a secure hospital server.

This aim of this study was to validate the function of the CM and CEM and their accuracy relative to UDS.

Institutional review board approval was obtained. All patients with NGB managed with intermittent catheterization undergoing routine UDS were eligible for study inclusion. At the completion of UDS, the instillation port of the 6-French dual-lumen UDS catheter was connected to the CM or CEM. Bladder parameters were simultaneously recorded using the device and UDS during bladder emptying. Correlative statistics were calculated.

A total of 36 patients (30 children/6 adults; age range from 1.2 to 38 years [median: 7.5 years]) underwent CM testing. Strong pressure correlation with UDS was identified (R² = 0.89). A total of 42 patients (30 children/12 adults; age range of 2.9-85.2 years [median: 12.2 years]) underwent CEM testing. Again, strong pressure correlation was found (R² = 0.77). Cystoelastometer volume measurements were highly correlated with measured volumes (Fig. 4, R² = 0.98).

Both the CM and CEM functioned well and transmitted the data wirelessly to a smartphone. The data from these devices were strongly correlated with simultaneous data from the UDS. A limitation is that these devices were used by healthcare providers, and therefore, use by patients or their parents/caregivers at home has not been demonstrated.

The CM and CEM devices provide accurate bladder pressure and volume measurements. The potential for improved patient monitoring and care is promising. Reliability testing and the effects of such monitoring on patient outcomes remain to be determined.