Chapter 167. Tympanocentesis

Tympanocentesis, first described in 1768, is a diagnostic and therapeutic procedure in which a needle is inserted through the tympanic membrane to aspirate fluid from the middle ear space (Figure 167-1). The procedure is considered diagnostic when the material obtained is sent for laboratory and/or microbiological analysis. It is considered therapeutic in most instances because it relieves pressure, thereby reducing pain and many times shortens the course of an acute otitis media (AOM).

The procedure is quick, simple, and not as frequently performed as it should be. In the preantibiotic era, general practitioners and pediatricians would frequently perform the procedure for the relief of pain. Tympanocentesis is making a resurgence. It should be considered when a patient presents to the Emergency Department seeking treatment for a painful AOM. The American Academy of Family Physicians, American Academy of Pediatrics, and the Centers for Disease Control all include tympanocentesis in their practice guidelines for AOM. Many authors are calling for culture-directed antibiotic therapy for otitis media to reduce the need for broad-spectrum antibiotics and prevent, as much as possible, the emergence of multiresistant organisms.1–6

The ear is divided into the external, middle, and inner parts. The external ear is comprised of the auricle, the external auditory canal, and the external auditory meatus. The middle ear contains an air space and mastoid cells ventilated by the eustachian tube, the tympanic membrane, and the three ossicles. The inner ear is comprised of the cochlea, semicircular canals, fluids, and cranial verve VIII. The facial nerve courses through the middle ear space and mastoid process. It can be affected by a severe infection in these areas. Facial asymmetry during an acute ear infection is an indication of an unusually severe infection.

Inspection of the tympanic membrane will usually show it to be bulging during an acute infection with loss of mobility on pneumatic otoscopy. Conditions that are more chronic may show color changes of the tympanic membrane, with or without associated scarring and distortion.

Tympanocentesis is performed to obtain fluid for microbiological culture and antibiotic sensitivity testing to determine the infectious cause of a middle ear effusion. Tympanocentesis is warranted for patients with AOM that is severe, unresponsive to 48 to 72 hours of conventional antimicrobial therapy, or in a child less than 8 weeks of age to rule out gram-negative organisms. Tympanocentesis is warranted for patients with an AOM and either an acquired or congenital immunodeficiency as they will often require directed therapy. Patients who develop AOM while taking appropriate antimicrobial therapy should undergo tympanocentesis to be evaluated for the organism responsible and its sensitivity to antibiotics. Tympanocentesis is also performed when the patient has an AOM associated with unusually severe pain, signs of toxicity, or bullous myringitis. Tympanocentesis will provide immediate relief of pain, pressure, and/or hearing loss associated with AOM or a middle ear effusion. It may be performed in a patient with AOM and multiple antibiotic allergies to determine appropriate antibiotic selection and sensitivity. Finally, it can be performed in the patient with AOM prior to the 48 hour “watchful waiting” period to allow accurate antibiotic selection if the patient is still symptomatic after 48 hours.

There are no absolute contraindications to tympanocentesis. It should not be performed in a patient who is uncooperative and cannot be restrained and/or sedated, as secondary injury may result. Uncooperative patients will require sedation to perform this procedure. Tympanocentesis should be performed by an Otolaryngologist if the landmarks on the tympanic membrane are unable to be absolutely identified or are obscured. Consult an Otolaryngologist prior to performing a tympanocentesis if an AOM is associated with a facial nerve palsy, mastoiditis, meningitis, encephalitis, brain abscess, or dural sinus thrombosis. Do not perform a tympanocentesis if the patient has an otitis externa.

• Topical otic anesthetic solution
• 21 gauge spinal needle, 2.5 or 3 inches long
• 3 mL aspirating syringe
• Ear speculum
• Ear wax curette
• Culture swabs and media
• Laboratory tubes for fluid cell count and differential
• Intravenous extension tubing
• Otoscope
• Headlamp or overhead surgical light source
• Frazier suction catheters
• Suction tubing
• Suction source
• CDT Speculum, optional

The Channel Directed Tympanocentesis or CDT Speculum (Walls Precision Instruments LLC, Baker City, OR) is a single patient use, disposable, easy to use, and sterile device with built-in safety features. It was designed for use by Primary Care Physicians in the outpatient setting. The CDT Speculum attaches to most commonly available otoscopes (Figure 167-2). The device allows tympanocentesis and the aspiration of middle ear effusions.

There are several advantages to this device over the traditional spinal needle on a syringe. The ensheathed needle protects the Emergency Physician as well as the patient from accidental needle sticks. The needle is incorporated into a speculum to prevent it from contacting the external auditory canal. The needle is automatically retracted by a spring into a protected position when not being used. A safety latch prevents accidental needle extension. Needle extension is limited and prevents it from being inserted too far into the middle ear cavity.

Explain the risks, benefits, and potential complications of the procedure to the patient and/or their representative. The postprocedural care should also be discussed. Obtain a signed consent for the procedure.

Place the patient supine on a locked gurney. View the tympanic membrane with an otoscope. Remove any cerumen from the external auditory canal using a curette. The cerumen may also be flushed from the external auditory canal. Refer to Chapter 166 for the complete details regarding cerumen removal. Again, view the tympanic membrane with an otoscope.

Administer analgesic medicine in advance of the procedure. Topical anesthetic solutions include benzocaine–antipyrine (e.g., Auralgan), viscous 4% lidocaine, 8% tetracaine, and cocaine. The administration of topical or local anesthesia is often not helpful in the presence of an acute infection. Topical anesthetics can potentially affect culture results due to their antimicrobial activity. If culture results are not a concern, apply a topical anesthetic solution into the external auditory canal followed by a cotton ball. Allow the solution to remain for 5 to 10 minutes. Use a wick to absorb the topical anesthetic solution and dry the external auditory canal. Refer to Chapters 126 and 168 for the details regarding regional anesthesia of the ear.

Children and uncooperative patients must be restrained and/or sedated so that the head is immobile. A papoose is effective for young children. Some practitioners use intravenous sedation. Only rarely is procedural sedation or general anesthesia required.

Traditional Needle-Based Technique

Bend a 21 gauge spinal needle at the hub to approximately 60°. Attach the spinal needle to a 3 mL aspirating syringe. Insert the ear speculum into the external auditory canal (Figure 167-1A). View the tympanic membrane through the ear speculum using a headlight or overhead surgical light source for illumination or an operating otoscope.

Insert the spinal needle through the speculum. Advance the needle and penetrate just into the inferior half of the tympanic membrane (Figures 167-1A & B). Avoid inserting the needle through the posterior superior quadrant of the tympanic membrane. This location is near the ossicles. Any movement of the needle near the ossicles could result in disarticulation of the ossicles requiring surgical repair. Aspirate the middle ear fluid into the syringe (Figure 167-1A). Simultaneously withdraw the syringe and ear speculum.

Channel Directed Tympanocentesis (CDT) Speculum

Remove the sterile CDT Speculum from the package. Attach the aspirator bulb and tubing to the CDT Speculum. Attach the CDT Speculum to the otoscope. Align the arm of the CDT Speculum with the insufflator port of the side of the otoscope head. Firmly attach the CDT Speculum onto the otoscope. Rotate the CDT Speculum 90° clockwise so that the arm is aligned with the seam on the top of the otoscope head. Disengage the safety latch.

Grasp the CDT Speculum with the dominant hand while simultaneously holding the otoscope and aspiration bulb with the nondominant hand (Figure 167-3). Compress the aspirator bulb. Insert the CDT Speculum into the external auditory canal. Visualize the tympanic membrane through the CDT Speculum. While looking through the CDT Speculum, press the actuator with the dominant thumb to extend the needle toward the inferior portion of the tympanic membrane (Figure 167-3). Continue to press the actuator to keep advancing the needle through the tympanic membrane and no more than 1 to 2 mm into the middle ear cavity. Release the compression on the aspirator bulb to aspirate the middle ear fluid. Release the pressure on the actuator to retract the needle. Withdraw the CDT Speculum from the external auditory canal.

Place the tip of the CDT Speculum over the culture swab or medium. Compress the aspirator bulb to expel the middle ear fluid sample. Discard the CDT Speculum.

An alternative method involves attaching intravenous extension tubing between the spinal needle and the syringe. The Emergency Physician can observe the tympanic membrane, insert the spinal needle, leaving a hand available for manipulation of the ear speculum or a suction catheter. An assistant is required to hold the syringe and aspirate the middle ear fluid. The remainder of the technique is as described previously.

Tympanocentesis will decompress the middle ear pressure and provide the patient significant symptom relief. Transfer the fluid into appropriate laboratory medium and containers as quickly as possible. Label the containers and have them transported to the laboratory for a Gram's stain, culture and sensitivities, cell count, and differential of the cells present.

Since most of the distress associated with the procedure in small children is due to immobilization, immediately release the child from the papoose or restraining device. Most patients will have immediate improvement in their pain and, in many cases, their hearing. Some Otolaryngologists will rinse the external auditory canal after a tympanocentesis with a 3% peroxide solution then absorb the solution with a wick. This is optional and at the discretion of the treating Emergency Physician. Because there is a small opening in the tympanic membrane, further drainage including bleeding may occur and should be expected for 48 to 72 hours. Instruct the patient and/or their caregivers to keep the ear dry for 2 to 3 days. This is especially true during bathing or hair washing. A cotton earplug coated with a thin film of petrolatum jelly (e.g., Vaseline) works well. The tympanic membrane usually spontaneously heals within 48 to 72 hours, but can take up to 10 days. Follow-up for laboratory results and documentation of antimicrobial change or appropriateness is necessary in 48 to 72 hours.

Complications are uncommon. The most frequently cited complications include laceration of the ear canal, persistent perforation with or without otorrhea, development of a scar on the tympanic membrane, and an otitis externa. Pain and bleeding are usually minimal and self-limited. One of the most significant (but rare) complications is the disruption of the ossicles of the middle ear. Disruption of the ossicles can be avoided by inserting the needles into the inferior half of the tympanic membrane and preventing patient movement during the procedure. Injury to the chorda tympani, facial nerve, or internal carotid artery is theoretically possible, but virtually unheard of with this procedure.

Acute otitis media is a common infection of childhood, but is also seen in adults. Most episodes respond quickly, with or without antimicrobial therapy. Tympanocentesis can be used to direct antimicrobial therapy in patients when a clinical response is delayed, host immunosuppression exists, or unusual organisms are suspected. Tympanocentesis can be used to provide immediate pain relief from a severe middle earache. The procedure is quick and simple to perform in the Emergency Department.