From the Guidelines
A tympanogram value of -180 mm H2O indicates negative middle ear pressure, suggesting Eustachian tube dysfunction, which is consistent with a Type C tympanogram. This finding shows reduced compliance of the tympanic membrane due to negative pressure in the middle ear space. The normal tympanometric peak pressure range is between -100 and +50 mm H2O, so a reading of -180 mm H2O is significantly more negative than normal 1.
Key Points
- The negative pressure can result from poor Eustachian tube function preventing proper ventilation of the middle ear.
- Patients with this finding may experience symptoms such as ear fullness, mild hearing loss, popping sensations, or discomfort, especially with altitude changes.
- Treatment typically focuses on improving Eustachian tube function through nasal decongestants, nasal steroid sprays, or techniques to help open the Eustachian tube such as the Valsalva maneuver (pinching the nose and blowing gently) 1.
- If persistent, this condition may predispose to middle ear effusion and should be monitored, particularly in children where chronic negative middle ear pressure can affect hearing and language development 1.
Clinical Implications
- The management of negative middle ear pressure due to Eustachian tube dysfunction involves a combination of medical and surgical interventions.
- Clinicians should educate caregivers of children with tympanostomy tubes regarding the expected duration of tube function, recommended follow-up schedule, and detection of complications 1.
- The decision to perform tympanostomy tube insertion should be based on a comprehensive evaluation of the child's condition, including the presence of middle ear effusion, hearing difficulties, and symptoms attributable to otitis media with effusion.
From the Research
Tympanogram Value Interpretation
- A tympanogram value of -180 mm H2O indicates a significantly negative pressure in the middle ear, which may be indicative of pathology 2.
- This value is associated with a type C tympanogram, which suggests a negative ear pressure 2.
- According to a study on middle-ear pressure and eustachian tube function, a negative middle-ear pressure does not always denote a closed tube, and a flat tympanogram does not necessarily indicate a middle-ear effusion 3.
- The study also found that a systematically reduced tubal opening was noted as the middle ear pressure decreased from 0 to -200 mm H2O, which may be relevant to the interpretation of the tympanogram value 3.
Possible Indications
- Negative ear pressure is a possible indication of a tympanogram value of -180 mm H2O 2, 3.
- Middle ear effusion or other pathologies may also be considered, but the tympanogram value alone is not sufficient to confirm these conditions 2, 3.
- A normal tympanic membrane or tympanic membrane perforation are less likely to be indicated by a tympanogram value of -180 mm H2O, as this value suggests a significant negative pressure in the middle ear 2.