Science: Red Light for Oxygen

As modem aircraft climb toward the stratosphere, oxygen masks and pressurized cabins become a necessity. The trouble is that now & then something goes wrong with the man-made atmosphere. And one of the first symptoms of hypoxia (insufficient oxygen)* is a giddy self-assurance, a fine feeling that all’s right with the world. Many unexplained crack-ups may have been caused by pilots in euphoria, blissfully unaware that their skill and judgment were failing with their failing oxygen.

This week, at the Air Force’s School of Aviation Medicine, scientists were busy perfecting an accurate little gadget that will warn the high-altitude flyer when the oxygen in his bloodstream is dropping toward the danger point. Clamped on the translucent cartilage of a pilot’s ear, a tiny light bulb emitting red and infra-red rays will shine through the ear lobe to illuminate a small photoelectric cell. As the oxygen saturation of the pilot’s blood drops below its normal 98%, it will turn a darker, heavier red. Less light will filter through his ear lobe and less current will be given off by the photoelectric cell. A red warning light, connected to the ear unit, will flash in time for the pilot to repair his oxygen supply or get his plane down to a safe altitude.

* Not to be confused with anoxia, total absence of oxygen.