R439 – Effect of Resistance-Compliance Changes in Fluidic Systems
Problem Previous work has established the relationship of resistance and compliance in a bench-top model of 2 parallel fluid systems representing endolymph and perilymph. The R-C Product is mathematically proportional to the time to equilibrium. Increasing the resistance to fluid movement in the “endolymph” significantly increased the time to hydrostatic equilibrium between the systems. The current study was designed to test whether a compensatory change in the R-C Product on the “perilymphatic” side would reduce the time to steady state. Methods As previously described, 2 parallel tubular systems with symmetric resistance and compliance members were perturbed by rotating the model from a horizontal, equilibrium condition to an upright, disequilibrium condition. Time to steady state was video recorded in 4 resistance conditions. The primary test was whether increased resistance to flow on the “endolymph” limb would be negated by an equal increase to resistance to flow on the “perilymph” limb. Results All 4 resistance conditions exhibited differences in time to steady state by ANOVA (p = 3.4 × 10E-12). Mean time to a steady state was reduced when a compensatory change in resistance was applied to the “perilymph” limb (1.0 + 1.1 sec) when compared to high resistance in the “endolymph” alone (2.5 + 1.3 sec, p = .01). Conclusion Compensatory changes in the R-C Product can reduce time to equilibrium. Significance Improved treatment of vertigo may be possible by application of principles that can affect resistance (fluid pathway diameter or viscosity) or compliance (stiffness of the oval or round window) of the systems. Support University of Minnesota Biomedical Engineering Institute Otolaryngology Interest Group Fund.