Clinical Resource: Deep Ear Flush, Step by Step

Sandra Koch, DVM, MS, DACVD
College of Veterinary Medicine, University of Minnesota

Deep ear flushing is very helpful not only as a diagnostic tool in assessing chronic otitis but also as part of the treatment plan.¹ A short course (2 to 3 weeks) of an anti-inflammatory dose of oral and/or topical glucocorticoids may be needed before deep ear flushing in order to decrease inflammation and stenosis of the ear canals.

The deep ear flush procedure should be performed with the patient under general anesthesia so that the ear can be completely cleaned and the ear canal and tympanic membrane examined. Anesthesia also allows the placement of an endotracheal tube, which precludes the aspiration of fluids that may pass through the middle ear into the auditory tube and then into the posterior pharynx. Ideally, computed tomography of the tympanic bulla should be performed before the flush to stage ear disease and help make the decision to perform myringotomy if otitis media is present. Make sure to collect samples for cytology and bacterial culture and sensitivity testing (C/S) before flushing.

Several techniques to clean and flush the ears exist¹; below is the method I use in practice.

Procedure

1. Evaluate the canal to determine the severity of disease, the type and amount of debris in the canal, and the best initial approach for removing the debris.

2. After examination, if the debris is waxy, soak the external ear canal for 5 to 10 minutes with a ceruminolytic ear cleaner.

3. Flush the ear with warm sterile isotonic saline. A video-otoscope is ideal for this procedure because of its superior magnification and flushing equipment; however, a bulb syringe or an 8-French polypropylene urinary catheter attached to a 12 mL syringe passed through an otoscopic cone can be used. Alligator forceps and ear curettes can be used to remove larger debris.

4. Once the ear is clean, evaluate the tympanic membrane.

5. If the tympanic membrane is not intact, obtain samples from the middle ear cavity for cytology and C/S.

    ●  If using a handheld otoscope:

• Insert a sterile otoscopic cone into the horizontal ear canal and pass a sterile pediatric-size needle into the middle ear cavity to obtain samples for cytology and C/S.

    ●  If using a video-otoscope:

• Place an open-end 3½-French tomcat catheter attached to a 12 mL syringe through the port of the otoendoscope.
• Obtain two samples. For each sample, flush a small amount of saline into the middle ear cavity and aspirate it back. The first sample is for culture, and the second sample is for cytology.
• The video-otoscope channel can also be used for passing instruments to obtain biopsy specimens or collecting samples.

6. If the tympanic membrane is intact and appears abnormal, and otitis media is suspected or confirmed with imaging, perform myringotomy to obtain samples for cytology and bacterial C/S and to flush the middle ear cavity. In dogs, an intact tympanic membrane does not rule out the possibility of otitis media.

   ●  If using a handheld otoscope:

• Insert a sterile otoscopic cone into the horizontal ear canal and visualize the tympanic membrane.
• Using a spinal needle, a special myringotomy knife, make an incision into the caudoventral quadrant of the tympanic membrane, specifically the pars tensa.
• Collect 2 consecutive samples by passing sterile pediatric-size needles through the incision. The first sample collected is submitted for bacterial C/S and the second for cytologic analysis.

   ●  If using a video-otoscope:

• Place an open-end 3½-French tomcat catheter through the port of the otoendoscope and use the catheter to make the incision.
• Flush saline into the middle ear cavity and aspirate it back using a 12 mL syringe attached to the tomcat catheter. Submit the first sample for C/S and the second for cytology.

Postprocedure Management

A normal tympanum usually heals in 21 to 35 days. Therefore, if the ear is kept free of infection after myringotomy, the tympanic membrane should heal within 5 weeks.

Non-ototoxic antibiotic and steroids may be infused inside the middle ear and external ear canal after the ear flushing, if necessary. The patient may also be sent home on empiric topical and systemic therapy according to cytology results, and treatment may be modified once C/S results are available. The ototoxicity of most topical otic medications is not known, so if a myringotomy is performed, owners should be instructed to watch for signs of ototoxicity and discontinue the otic medications if they occur. Signs of ototoxicity include the following:

• Horner syndrome
• Facial nerve paralysis
• Vestibular disturbances
• Deafness

Owners should be made aware of these potential complications and sign a consent form before deep ear flush and myringotomy are performed.

A short course of oral glucocorticoids and pain medication may be sent home with the patient to reduce discomfort and inflammation associated with the procedure, particularly if trauma to the ear canal occurs or myringotomy is necessary.

Recheck the patient 2 to 4 weeks after the ear flush to monitor the response to otic treatments and evaluate the status of the tympanic membrane, particularly if myringotomy was performed.

Reference

1. Patterson S, Tobias KM. Atlas of Ear Diseases of the Dog and Cat. Ames, IA: Wiley-Blackwell; 2012.