A Volunteer Crossover Feasibility Study to Compare Standard Oxygen Cannula Used at High-Flow to Proprietary High-Flow Humidified Nasal Oxygen Systems

Background and aim: Supplemental oxygen is routinely administered to patients prior to and during induction of general anesthesia and sedation. This increases the fraction of oxygen in the lungs, increases oxygen delivery, and increases the time to oxygen desaturation. Proprietary Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) systems, which deliver warmed and humidified oxygen, have been extensively researched in the perioperative and critical care setting and have been shown to significantly prolong time to desaturation and as a means of ventilatory support. The use of traditional nasal oxygen cannula used at maximum flow rates is currently used in short bursts as it is poorly tolerated. There is however a dearth of data examining the use of this technique. We hypothesized that traditional nasal oxygen cannulae used at maximum flow rates can deliver oxygen as effectively as THRIVE in this setting. Methods: We designed a crossover volunteer feasibility study. The participants were 10 healthy anesthetists. We compared the two methods of oxygen delivery by measuring transcutaneous oxygen measurement and pharyngeal oxygen concentration. Comfort and noise levels were recorded. The aforementioned parameters were compared between the two groups. Results: We observed that a standard oxygen cannula used at high flows delivers comparable oxygen delivery and tissue oxygenation performance to proprietary THRIVE systems. However, they are less comfortable and make more noise. Discussion: To the authors' knowledge this study is the first to study the oxygen delivery of traditional nasal oxygen cannula used at maximum flow rates and make comparisons to the well-studied THRIVE technique. While similar transcutaneous partial pressure of oxygen and pharyngeal gas concentrations were observed with both techniques, the standard cannulae were deemed to be a lot less comfortable than THRIVE and made a lot more noise which likely limit the utility of this technique outside of short bursts. Conclusion: In this study, a standard nasal oxygen cannula used at high flows achieved similar oxygen delivery to THRIVE at the expense of poor comfort and increased noise.