Risk Factors for Middle Ear Barotrauma in Patients with Carbon Monoxide Poisoning Undergoing Monoplace Hyperbaric Oxygen Therapy: A Retrospective Cohort Study.

Background

Hyperbaric oxygen therapy (HBOT) is the standard treatment for moderate to severe carbon monoxide (CO) poisoning, but middle ear barotrauma (MEB) remains a common complication. This study identified risk factors associated with MEB in patients undergoing monoplace HBOT.

Methods

This retrospective cohort study included patients treated for CO poisoning with monoplace HBOT at a tertiary academic hospital between May 2021 and December 2023. MEB severity was assessed before and after treatment using video otoscopy and graded according to the modified O'Neill Grading System.

Results

MEB occurred predominantly at lower severity grades according to the O'Neill scale. In univariate analysis, significant risk factors for MEB included altered mental status at presentation (OR: 3.16, 95% CI: 1.35-7.40, p = 0.008), serum albumin > 4.3 g/dL (OR: 0.22, 95% CI: 0.10-0.65, p = 0.004), and magnesium levels (OR: 0.21, 95% CI: 0.05-0.98, p = 0.046). Multivariate analysis confirmed altered mental status (OR: 3.16, 95% CI: 1.05-9.52, p = 0.041), albumin > 4.3 g/dL (OR: 0.26, 95% CI: 0.10-0.65, p = 0.004), and magnesium level (OR: 0.21, 95% CI: 0.05-0.88, p = 0.033) as independent predictors of MEB. Patients with higher albumin and magnesium levels showed lower risk.

Conclusions

Altered mental status, lower albumin, and lower magnesium levels predicted middle ear barotrauma in patients undergoing monoplace HBOT for CO poisoning. These findings highlight the importance of careful pre-treatment evaluation and close monitoring during therapy to reduce the incidence of MEB.