Development and testing of a vaginal pressure sensor to measure intra-abdominal pressure in women

Elevated intra-abdominal pressure (IAP) may be a potentially modifiable risk factor for pelvic floor disorders. However, limited evidence exists due to the lack of instruments suitable to measure abdominal pressures in real world settings. The aim of this study was to develop and test a vaginal sensor prototype to measure intra-abdominal pressure in women.

We developed a non-directional vaginal sensor by housing pressure-sensing circuit boards in 1.2 x 3 cm radially symmetric silicon capsules. We characterized the response in a standardized pressure chamber. Eight women wore a sensor intra-vaginally while undergoing filling cystometry. We compared peak pressures during coughing, valsalva, squatting, and jumping to those obtained using a #10 French rectal balloon urodynamics catheter. We calculated Pearson's correlation coefficients between rectal and vaginal sensors for each event.

The vaginal sensors exhibited linear responses during initial bench testing. Each transducer correlated well with the rectal balloon catheter during coughing, valsalva, and squatting (r = 0.97, 0.94, and 0.97, respectively). However, the rectal balloon catheter recorded higher peak and lower, often negative, trough pressures during jumping. The vaginal sensor showed no such artifact.

This vaginal pressure sensor can be used as a surrogate for measuring intra-abdominal pressure in women without advanced prolapse. By measuring pressure at the physiological source, the vaginal sensor is less prone to extraneous noise and error than current transducers. Using this prototype, we will next develop a remote wireless version to capture a range of abdominal pressures experienced outside of the laboratory setting.