Eustachian tube dysfunction (ETD) and middle ear barotrauma (MEB) are common reported complications during hyperbaric oxygen treatment. The Phase I study data was the first to demonstrate a statistically significant decrease in the occurrence of symptomatic ETD and middle ear barotrauma (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 total time interval and rate of compression to reduce ETD and MEB when considering each multiplace treatment (with multiple patients) as the unit of observation collectively as a group, rather than for each individual patient. Data will be collected prospectively on group patient-treatment exposures. Our investigators randomly assign patient-treatment group exposures to two different rates (slopes) of compression. These are limited to the linear versus the non-linear rates (slopes) of compression identical to two of four compression profiles used in the Phase I and Phase II trials. All patients experiencing symptoms of ETD and MEB requiring compression stops will be evaluated post treatment to confirm the presence of ETD and MEB using the O'Neill Grading System (OGS). Data will be analyzed using the IBM-SPSS statistical software program. The number of compression holds observed in each of the compression schedules/compression profiles using an identical 15-minute total time interval of compression but varying in the rate (slope) of compression will be recorded as in the Phase I and II studies. Symptomatic patients who required compression stops (as in the Phase I trial) using a USN TT 9 during elective hyperbaric oxygen treatments in a Class A multiplace hyperbaric chamber will be compared. Statistical analysis using descriptive and Inferential statistics will be applied to the patients requiring first stops in the compression profiles. This will be used to further evaluate the data restricted to the rate of compression (linear vs. non-linear) and whether this is associated with the number of compression holds. The 15-minute total time interval of compression will be identical in both compression profiles studied since this was found to be the total time interval of compression with the least number of treatment stops/holds in the phase I and phase II studies.