The effect of total compression time and rate (slope) of compression on the incidence of symptomatic Eustachian tube dysfunction and middle ear barotrauma: a Phase II prospective study.

Eustachian tube dysfunction (ETD) and middle ear barotrauma (MEB) are common reported complications during hyperbaric oxygen treatment. Our Phase I study data was the first to demonstrate a statistically significant decrease in the occurrence of symptomatic ETD and MEB. The Phase I Trial suggested the total time interval and rate (slope) of compression (ROC) may be a determining factor in ETD and MEB. This Phase II study investigates an optimal rate of compression to reduce ETD and MEB when considering each multiplace treatment (with multiple patients) as the unit of observation as a group, rather than for each individual patient. Data were collected prospectively on 1,244 group patient-treatment exposures, collectively including 5,072 individual patient-treatment/exposures. We randomly assigned patient-treatment group exposures to four different time interval and rate (slope) of compression. These compression rates and slopes were identical to those used in the Phase I trial. All patients experiencing symptoms of MEB requiring compression stops were evaluated post treatment for the presence of ETD and MEB using the O'Neill Grading System (OGS) for ETD. Data were analyzed using the IBM-SPSS statistical software program. A statistically significant decrease in the number of compression holds was observed in the 15-minute compression schedule, correlating to the results observed in the Phase I trial. The 15-minute linear compression profile continues to demonstrate the decreased need for patient symptomatic compression stops (as in the Phase I trial) using a USN TT9 during elective hyperbaric oxygen treatments in a Class A multiplace hyperbaric chamber. Trial Registration: ClinicalTrials.gov Identifier: NCT04776967.

The effect of compression rate and slope on the incidence of symptomatic Eustachian tube dysfunction leading to middle ear barotrauma: a Phase I prospective study.

Introduction: Symptomatic Eustachian tube dysfunction (ETD) and middle ear barotrauma (MEB) are the most common reported complications during hyperbaric oxygen (HBO2) treatment. There is no standardized rate of compression (ROC) reported to decrease the incidence rates of ETD and MEB during hyperbaric treatments. Few studies actually demonstrate that the ROC decreases the incidence of ETD or MEB. Methods: Our study was designed to determine an optimal hyperbaric chamber compression rate that might reduce the incidence of symptomatic ETD leading to MEB during the compression phase of treatment in a multiplace hyperbaric chamber. Data was collected prospectively over 2,807 elective patient treatments compressed using a U.S. Navy Treatment Table 9 (USN TT9) with a modified ROC. ROC was assigned using two variables, time (10 vs.15 minutes) and slope (linear vs. non-linear compression). Patients were exposed to all four compression schedules in a consecutive daily fashion. We recorded any patient requiring a stop during initial compression due to ear discomfort. Anyone requiring a stop was evaluated post treatment for MEB. Findings were compared to our standard 10-minute linear ROC. Evaluation of the tympanic membrane was accomplished using video otoscopy. Barotrauma when present was classified using both the Teed and O'Neill grading systems. Data was analyzed using basic statistical methods. Results: When comparing four different rates of compression during an elective USN TT9 in a multiplace (Class A) chamber there is a decreased incidence for symptomatic ETD when using a 15-minute linear compression schedule (p-value ⟨0.05). Conclusion: Using a 15-minute linear compression schedule is associated with less symptomatic ETD and less MEB when performing an elective 45 fsw (USN TT9) hyperbaric treatment in a Class A chamber. Asymptomatic ETD and MEB were not considered in this study.