Mp77-05 Low Amplitude Rhythmic Contractions Influence Sensations of Urgency in Patients With Overactive Bladder Syndrome

Abstract

Low amplitude rhythmic contractions (LARC), visualized as phasic intravesical pressure (pves) changes, are commonly seen during urodynamics (UD). A significant rise in pves will increase bladder wall tension and can elicit an increase in sensation. LARC are dampened by the viscoelasticity of the bladder, and not all elevations in bladder wall tension are expected to be sufficient to cause an increase in sensation. This study aims to determine thresholds for pves amplitude elevations that trigger patient-reported changes in sensation during filling.METHODS: As part of an IRB-approved urodynamics (UD) protocol, patients with overactive bladder syndrome (OAB), defined as ICIq-OAB question 5a ¼ 3, underwent standard UD testing and simultaneously used a real-time sensation meter to record continuous changes in sensation from 0-100% during filling. Patients were instructed on use of the meter prior to the study. Sensation values were time-linked to pves. Normalized pves was differentiated to identify inflection points, and baseline pves was calculated via polynomial regression (Figure 1). Significant elevation in pves from baseline was defined as ¼ 5% normalized value, while any elevation in patient-reported sensation (values sampled every 10 sec) was considered significant. Significant phasic rises in pves were juxtaposed to sensation changes to determine if pves and sensation events coincided.RESULTS: Twelve patients underwent UD with use of the sensation meter e 3 were excluded (transducer error, fill to 30mL, only 10% sensation reached). Average phasic pves and sensation change event frequencies during filling were similar: 2.0AE0.2 & 2.1AE0.3 cycles/ min, respectively (p¼0.9). Of sensation changes, 53AE8% were within 10 sec of significant pves elevations (average ?pves ¼ 20AE3% normalized minimum).CONCLUSIONS: The frequency of changes in patient-reported sensation during filling correspond with phasic pves elevations, generated by LARC. Further refinement of sensation thresholds may allow development of non-invasive techniques to better characterize a LARC-mediated subtype of OAB.

Quantification of bladder wall biomechanics during urodynamics: A methodologic investigation using ultrasound

“…DO was diagnosed all five participants and transient rises in pressure tended to be associated with increases in bladder sensation (Colhoun et al, 2016a). Average Pves during the initial fill and fill with ultrasound were 54.0±11.4 and 42.7±11.4 cmH2O.…”