Middle ear effusion in mechanically ventilated patients: effects of the nasogastric tube.

Background: Middle ear effusion (MEE) is rare among adults, but has a higher incidence among ICU patients. The aim of this study was to analyze the effect of nasogastric tube (NGT) on MEE and to assess other predisposing factors.

Methods: Prospective observational study, carrying out an otoscopic examination and tympanometry in 100 mechanically ventilated patients. Immittance testing was carried out within 24 hours of ICU admission and every 72 hours until ICU discharge. In a case of persisting pathologic curve at the moment of discharge from ICU, there was a follow-up examination every 3 days until middle ear function was restored. In addition to descriptive variables, we recorded placement (left or right nostril) and diameter (12, 16, or 18 French) of the NGT. A Cox regression analysis was performed, adjusted for the days since ICU admission.

Results: A total of 535 tympanometry studies were carried out, of which 352 were normal and 183 observations presented MEE. We observed that 12 and 16 French NGTs were not significantly associated with abnormal middle ear function, whereas 18 French NGT was significantly associated with MEE (odds ratio 2.54, 95% CI 1.42-4.55; P = .01). Other variables independently associated with pathological tympanogram curves were Ramsay Sedation Scale score ≥ 4 (odds ratio 2.42, 95% CI 1.65-3.55; P = .01) and orotracheal intubation (odds ratio 5.72, 95% CI 3.40-9.60; P = .01). No intracranial infection or long-term disabilities were identified.

Conclusions: MEEs and tympanometric alterations are frequent in intubated patients (32% in our study). To prevent these complications, they should receive NGTs with a diameter lower than 18 French, when feasible.