Oxygen on the sidelines

Working in the emergency room 6 or 10 yrs ago it was common to pull the phalange from the one-way valve in a plastic non-rebreathing oxygen mask and apply to patients without any oxygen flowing through it to treat anxiety (hyperventilation). A lunch size paper bag would have physiologically been more effective at raising blood carbon dioxide levels and restoring blood pH, but I suppose the mask had a better psychological effect. Besides, no one wants to pay that big bill if treatment consisted of breathing into a brown paper bag. We drew a blood gas or two for good measure (actually, to rule out any metabolic pathology).

Hyperventilating can lead to loss of consciousness, especially when combined with the bodies flight-or-fight responses associated with anxiety. Usually, the EMS first intervention for an unconscious person is oxygen. So much for the need for oxygen on the sidelines. Too much oxygen can have a weak acid effect in the blood, but for the short few minutes it really isn't counter productive, and if it gets you to calm your breathing down... But, a paper bag's cheaper.