Evaluation of resistance of oxygen regulators in hyperbaric chambers

Introduction: In our study, we evaluated the compliance of resistance of inspiratory (demand) and expiratory (exhaust) regulators in the respiratory systems of pressure chambers in hyperbaric oxygen therapy (HBOT) centers to the standards of TS EN 14931. The high resistance of these regulators reduces the patient's comfort and compliance with treatment. In addition, we aimed to raise awareness that the high resistance of these regulators may be a factor in HBOT's rare complications. Materials and methods: 21 hyperbaric oxygen treatment centers with multi-person pressure chambers were visited. At 2,4 ATA treatment pressure, four regulators were randomly selected, two regulators from right and left sides of the pressure chamber were tested. With the differential pressure digital manometer integrated into the mask assembly, maximum and minimum pressures during inspiration and expiration, while using different trademark masks, were recorded in calm breathing and challenging breathing (with at least 3 repetitions). The data obtained in the study were edited in Microsoft Excel program. Results: Measurements were made from a total of 84 inspiratory and 84 expiratory regulators. During normal breathing, the regulator with the most resistance to inspiration was found to be Avox® with 11.4 cmH2O and the regulator with the lowest resistance was Haux® 2 cmH2O. In normal respiration, the regulator most resistant to expiration was Galeazzi with 22.8 cmH2O, and the regulator with the least resistance was Haux® with 1 cmH2O. We found that 65.5% of inspiratory regulators and 31% of expiratory regulators were not suitable to TS EN 14931 standards. We have determined that regulatory maintenance is not carried out regularly. Conclusion: In our study, it was determined that the majority of the inspiratory and expiratory regulators measured did not meet the standards. It was learned that there was no routine practice in the maintenance of regulators. Increased respiratory workload due to high pressures in the mask causes patients to use the mask without sitting well on their face. The effectiveness of the treatment decreases as ambient air is inhaled with the mask, which is not used effectively. In addition, oxygen leakage occurs from the mask, and makes it difficult to control the O2 percentage inside the pressure chamber. It is a known fact that high pressures in expiratory regulators increase the risk of pulmonary barotrauma. We believe that when issuing new certificates, this work will be a reference to the Ministry of Health and the manufacturers will review their regulator systems in light of this data and assist in periodic maintenance of pressure chambers. Key Words: Hyperbaric chamber, Hyperbaric Oxygen Therapy, regulator