Electroacoustic assessment of the semipermeable tympanic ventilating tube. A physical model

The semipermeable membrane ventilating tube has been in use for the past few years. Initial evaluation of this tube indicated that electroacoustic impedance measurements could be used to measure in situ patency. Our clinical experience seemed to question this assumption. A physical model was developed to evaluate the validity of using electroacoustic impedance measurements to test patency of membrane-type ventilating tubes. Our results indicate that volume impedance measurements cannot be used to evaluate patency. Pressure clearance studies validated the efficacy of the membrane tubes but would not appear to be a reliable method for in vivo evaluation of patency.