Evaluation of two oxygen face masks with special regard to inspiratory oxygen fraction (FiO2) for emergency use in rescue helicopters.
BACKGROUND
Effective oxygenation during acute respiratory insufficiency depends on the inspiratory oxygen fraction (FiO(2)) 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 FiO(2) in the laryngopharynx of patients and to apply these data to the setting in rescue helicopters.


METHODS
In spontaneously breathing patients, FiO(2) was measured with an O(2)-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 <or= .05 was considered statistically significant.


RESULTS
Twenty patients with a mean age of 69 +/- 7 years were investigated. At a low oxygen flow up to 1 L/min, the Hi-Ox80 mask was not superior to the basic mask (FiO(2) at 1 L/min 24% +/- 3% vs. 27% +/- 5% and partial pressure of arterial oxygen [paO(2)] 164 +/- 68 vs. 193 +/- 53 mmHg; NS). Using a flow of 2 L/min or more, a significant difference for the FiO(2) and paO(2) in both masks was found (P <or= .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.


CONCLUSIONS
The 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 FiO(2). Thus, oxygen, cost, and weight savings are feasible.
Hinkelbein
Jochen
J
Clinic for Anesthesiology and Intensive Care Medicine, Medical Faculty Mannheim, Ruprecht-Karls-University Heidelberg, University Hospital Mannheim, Mannheim, Germany. jochen.hinkelbein@anaes.ma.uni-heidelberg.de
Glaser
Eckard
E
D000368:Aged; D000369:Aged, 80 and over; D017732:Air Ambulances; D004638:Emergency Treatment / Q000295:instrumentation; D005260:Female; D006801:Humans; D008297:Male; D008397:Masks; D008875:Middle Aged; D010100:Oxygen / Q000008:administration & dosage / Q000097:blood; D010102:Oxygen Inhalation Therapy / Q000295:instrumentation*; D012131:Respiratory Insufficiency / Q000628:therapy
D010100:Oxygen