Methods for preventing middle ear barotrauma in computer-controlled pressurization of monoplace hyperbaric chambers

Middle ear barotrauma (MEB), one of the side effects of hyperbaric oxygen (HBO2) therapy, sometimes cannot be directly diagnosed during the therapy itself. Instead, its incidence and degree are judged based on subjective statements made by patients when in conversation with medical staff regarding how they feel. To prevent MEB in practice, it is proposed that the tympanic membrane evaluation system and automatic control chamber developed in a previous study be applied as part of a prevention algorithm [16]. The proposed algorithm, which determines and equalizes the unbalanced pressure of a subject based on their tympanic admittance, was evaluated in conjunction with conventional HBO2 therapy in an experiment involving 100 subjects. Among the 50 subjects in the control group who received HBO2 therapy 16 subjects experienced MEB. In contrast, the experimental group of 50 subjects were treated with a hyperbaric chamber protocol incorporating the automatic control system and proposed algorithm. At the conclusion of the treatment, no subjects exhibited middle ear barotrauma. In the case of the control group, while the target pressure was achieved, middle ear barotrauma still occurred. However, in the case of the experimental group, the pressure inside the chamber was adjusted as per the algorithm, which allowed the target pressure for every subject to be achieved without experiencing MEB. When a particular subject was unable to perform any pressure equalization method such as swallowing or the Valsalva maneuver, the chamber was not pressurized based on the tympanic admittance and thus no MEB occurred.