FIO2 Capability of a Procedural Oxygen Mask During Different Breathing Patterns and Oxygen Flows

Abstract

Background: The Procedural Oxygen Mask (POM) is a multiport mask that is designed to allow scopes, probes, and tubes through the mask and into the mouth or nose while claiming to deliver high levels of oxygen. The goal of this study was to determine the actual O₂ delivery at the carina while wearing the POM mask at different flows, breathing patterns, and integrity of the masks oral access membrane. Our hypothesis is that there will be no difference in O₂ delivery at the carina from the POM based on breathing pattern, flow, or status of the POM masks oral membrane. Methods: A bench model was created by adapting an adult intubation manikin (Armstrong Medical Industries, Lincolnshire, IL) to an Ingmar Medical ASL 5000 (Pittsburgh, PA) breathing simulator. Tygon tubing and appropriate adapters connected the manikin’s trachea with the breathing simulator’s outlet so that as the simulator operates, air flows in and out through the manikin’s mouth and nares. A TED 60T O₂ analyzer was connected to the simulated carina of a mannequin. The POM was secured to the face of the mannequin with manufacturer provided equipment and connected to an O₂ flow meter. The lung simulator was set at respiratory rates of 6, 12 and 25 breaths/min, and tidal volumes were set at 300 mL, 600 mL, and 925 mL, respectively. The flow meter was set to a flow of 10, 12, or 15 L/min with the manufacturer provided high flow adapter. The FIO₂ was measured by the analyzer for each breathing pattern. First with the membrane of the mask completely intact, then with a bronchoscope inserted with the aid of 0.045 oz PDI lubricating jelly, and lastly post mock bronchoscopy with membrane no longer intact. The O₂ analyzer was calibrated between each reading. Results: Statistical difference was found in the mean delivered FIO₂ between breathing patterns, flow meter settings, and if the masks membrane was intact. However, after the membrane is perforated the patients breathing pattern and O₂ flow are the primary factors that impact FIO₂ delivery. Average range of delivered FIO₂ across all runs was 38-84%. Conclusions: Delivered FIO₂ varied from 38-84% using the POM mask. The FIO₂ delivered by the POM mask is impacted by breathing pattern, flow of oxygen and intactness of membrane. During clinical use providers should be aware of this range and how these factors will impact the delivered FIO₂.

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