Indications. (i) As a means of diagnosis in order to determine (a) the amount and character of the obstruction within the Eustachian tube; (b) the condition of the mucous membrane and whether any exudation is present within the middle ear.
(ii) For the purpose of treatment. (a) In order to instil medicated drops or vapours into the Eustachian tube and tympanic cavity; (b) as a preliminary measure to the passage of bougies into the Eustachian tube or to washing out the tympanic cavity through the Eustachian tube.
(iii) Catheterization is preferable to Politzer’s method if only one ear is affected. Politzer’s method, on the other hand, is preferable to catheterization (a) in small children; (b) in the case of slight middle-ear catarrh if both ears are affected; (c) if the passing of the catheter is very difficult and causes pain owing to nasal obstruction; (d) in nervous individuals who object to the catheter; (e) if the sudden inflation by means of Politzer’s method is more effectual than by catheterization.
Points to notice before inflation. 1. Care must be taken that the lumen of the catheter is not obstructed, and that the compressed air bag and auscultation tube are also in working order.
2. The nose must be cleansed of all secretion; if filled with crusts or in a septic condition, inflation must be avoided.
3. The patient should be sitting. Sometimes on inflation of the ear, especially for the first time, an attack of giddiness or faintness may occur.
4. The nose should always be examined to see that the passage is free. If it be obstructed catheterization may be impossible, or some special manipulation will be required in order to pass the catheter through the nose.
5. In order to prevent muscular contraction of the palatal muscles, which may grip the end of the catheter and so prevent its entrance into the orifice of the Eustachian tube, the patient should be told to breathe quietly and keep the eyes open.
Fig. 209. Eustachian Catheter.