Evaluation of two oxygen face masks with special regard to inspiratory oxygen fraction (FiO2) for emergency use in rescue helicopters

IntroductionEffective oxygenation during acute respiratory insufficiency depends on the inspiratory oxygen fraction (FiO2) and the oxygen face mask used. Recent studies demonstrated significant advantages of the Hi-Ox80 mask as compared with a basic mask. The aim of this study was to measure FiO2 in the laryngopharynx of patients and to apply these data to the setting in rescue helicopters.MethodsIn spontaneously breathing patients, FiO2 was measured with an O2-sensor (Draeger Medical, Luebeck, Germany) in the laryngopharynx, depending on the adjusted oxygen flow. Flow increments of 1 up to 12 L/min were analyzed using a basic oxygen mask (Intersurgical Ltd., Berkshire, UK) and a Hi-Ox80 mask (Viasys Healthcare GmbH, Hoechberg, Germany) in a randomized order on the same patient. Data were applied to the special helicopter environment and analyzed with respect to oxygen delivery per minute and resulting equipment benefits. Statistika (StatSoft GmbH, Hamburg, Germany) and t-test were used for statistical analysis. P ≤ .05 was considered statistically significant.ResultsTwenty patients with a mean age of 69 ± 7 years were investigated. At a low oxygen flow up to1 L/min, the Hi-Ox80 mask was not superior to the basic mask (FiO2 at 1 L/min 24% ± 3% vs. 27% ± 5% and partial pressure of arterial oxygen [paO2] 164 ± 68 vs. 193 ± 53 mmHg; NS). Using a flow of 2 L/min or more, a significant difference for the FiO2 and paO2 in both masks was found (P ≤ .05). Using the Hi-Ox80 face mask in a rescue helicopter with standard oxygen flows, it demonstrated 3.24 times longer oxygen availability because of a reduced required oxygen flow and therefore a potential calculated weight reduction.ConclusionsThe Hi-Ox80 mask allows more effective use of the administered oxygen flow. Efficiency of the new mask is greater; hence, similar flow adjustment produces a significantly higher FiO2. Thus, oxygen, cost, and weight savings are feasible.