Dawn Logas,     Maitland, Florida

In-Office Ear Flushing (Under General Anesthesia)

A bulb syringe or a No. 3 to No. 12 Fr red rubber feeding tube attached to a 6- to 12-ml syringe is an excellent and relatively safe flushing apparatus for in-office use. The wide end of the tube must be trimmed to accommodate the syringe hub. The tip is then cut off the other end so the final length of the tube is 4 to 6 inches or one to two times the length of the ear canal. Both straight and curved dull Buck ear curettes can be used to remove large pieces of wax and debris. Once the horizontal canal has been cleared, it is usually easier to assess the status of the tympanic membrane. In many cases of chronic otitis, the tympanum is still difficult to visualize because the canal is stenotic secondary to hyperplasia and fibrosis. If the tympanum cannot be visualized, its status can be assessed indirectly by noting the disappearance of the feeding tube tip from view, the need for an excessive length of tubing, and the exiting of fluid from the nares. Any of these observations indicates a false middle ear or imperforate tympanum. If the tympanum is visually intact but this is a case of chronic otitis (>3 months’ duration), performing a myringotomy using a dull Buck curette, tomcat catheter, or 5 Fr polypropylene urinary catheter may be necessary. A specimen for culture should always be taken from the middle ear if there is any evidence of fluid behind the membrane or if there is membrane opacity and fibrosis.

The hazards of deep ear cleaning include inadvertent rupture of the tympanum, vestibular dysfunction, auditory dysfunction, contact irritation and allergy, and introduction of other pathogens.

At-Home Ear Flushing

In many cases a commercial solution in a squeeze bottle is all that is necessary for at-home ear flushing. If there is a great deal of purulent material, a bulb syringe should be used, and the owners instructed in its appropriate use.

The frequency of flushing prescribed for home care depends on the severity of infection, consistency of the discharge, chronicity of the otitis, presence of yeast or bacteria, and presence or absence of a tympanum. Initially the frequency of flushing in severe cases, especially resistant Pseudomonas infections, can be three to four times daily. In most cases of less severe otitis, twice daily suffices. As therapy continues, the frequency should decrease to several times per week and then once weekly to every other week prophylactically.

It is particularly important that dogs with chronic ear canal changes such as fibrosis, stenosis, and lichenification be placed on a maintenance at-home flushing program to help to remove the debris and acidify the canal, which helps prevent recurrence of active infections. The frequency of flushing ranges from two to three times weekly to once every other week.

Although flushing is extremely important in the management of both chronic and acute otitis, it is imperative that the clinician remember that flushing too vigorously and too frequently can also be detrimental to the otic epidermis. If excessive white ceruminous exudate is noted on otic examination, and otic cytologic analysis reveals only keratinocytes, the flushing frequency should be decreased.

Cleansing Solutions

Currently there are a multitude of veterinary ear-cleansing solutions, which contain many similar ingredients. Most of these ingredients are purported to fulfill one or more of the following functions: dissolve discharge, lubricate the canal, remove excess water from the canal, kill infectious organisms, and decrease inflammation (Table 113-1). The type of discharge, the degree of inflammation, the chronicity of the disease, and the status of the tympanic membrane all should be taken into consideration when selecting which solution to use in a particular case. Different solutions may also be recommended for at-home versus in-office use. In general, milder solutions are recommended for use at home to minimize the chances of contact irritation. Antiinflammatory agents are described elsewhere in this section (see Chapters 94 and 109). Some specific recommendations follow.