Oxygen Administration in the Emergency Department: Choosing the Appropriate Dosage and the Technology

Oxygen (O2), like any drug, should be administered only when indicated, and at the appropriate dose. The indications for O2 administration are to relieve global or regional hypoxia and to provide therapeutic hyperoxia. In treating hypoxia, one must first rule out low inspired O2 concentrations (FIO2). The causes of hypoxia can then be categorized into hypoventilation, which responds to small increases in FIO2, and increased venous admixture (“shunt”), which requires maximal FIO2. FIO2 up to about 0.4 can be administered via common plastic face masks and Venturi masks. Masks with O2 reservoirs can increase the FIO2 to about 0.7 at best. Masks with sequential gas delivery can provide FIO2s exceeding 0.9 and are best suited to provide therapeutic hyperoxia and treat diseases characterized by excess “shunt”. MeSH Words: oxygen mask; inspired oxygen concentration; non-rebreathing mask; hypoxia; peak inspiratory flow; oxygen therapy, sequential gas delivery