Physiological predictors of hematological tier outcomes in canine platelet-rich plasma: a prospective observational study.

Patulous Eustachian tube (PET) is commonly described as abnormal patency of the Eustachian tube (ET) that creates an increased passage of airflow into the middle ear. This air movement can result in symptoms of aural fullness, autophony, and amplified breathing that can be modulated with positional changes []. PET affects approximately 0.3%–6.6% of the population, with a higher prevalence in females []. Commonly reported comorbidities include environmental allergy, weight loss, laryngopharyngeal reflux, and anxiety, though their mechanistic relationship to PET remains unclear []. Despite increasing clinical recognition, the pathophysiology of PET remains poorly defined. Proposed mechanisms include reduced soft tissue volume within the cartilaginous ET and atrophy or sclerosis of the peritubal nasopharyngeal structures, though many cases occur without an identifiable structural cause []. Emerging evidence has shifted attention toward airflow dynamics, as maneuvers that temporarily alter airflow or reduce nasopharyngeal turbulence (e.g., Cottle maneuver, nasal tip elevation, and ear canal occlusion) often result in transient symptom relief []. Diagnostic criteria for PET, as described by the Japanese Otologic Society (JOS), incorporate subjective symptoms (autophony, aural fullness), improvement with positional changes or pharyngeal orifice obstruction, and objective findings such as tympanic membrane hypermobility with respiration or sonotubometric changes []. Computed tomography (CT) has been utilized primarily to exclude other conditions that present similarly, such as superior semicircular canal dehiscence, but its potential role in characterizing nasopharyngeal anatomical features associated with PET has not been systematically evaluated.