With the application of excess pressure into the nose and rhinopharynx during swallowing, the tubomanometer can record the opening parameters of the Eustachian tube and the pressure equalization function of the middle ear.
The principle and aim is to build up sufficient pressure in the nose and rhinopharynx that enables the tubomanometer to assess the latency = delay between the pressure application and the opening of the Eustachian tube. Deviations from standard values can be shown. The decisive value is the Opening Latency Index = R
R = (P1-C1):(C2-C1)
The following pictures show indication of the various phases of pressure increase in the nasal cavity and velum closure. Indication of insufficient or incomplete velum closure.
Ventilation of the middle ear: Indication of tube reaction and tympanic movement by recording the pressure variations in the outer ear. The recordings indicate the opening pressure and opening latency of the Eustachian tube.