Ever since a non-pressurized aircraft was able to fly above 10,000 ft., hypoxemia has been a known aviation danger. A new article, “The identification of hypoxia biomarkers from exhaled breath under normobaric conditions” indicates that there may be a better way to monitor this condition for pilots.
Hypoxemia or hypoxia, low blood oxygen, describes a medical condition in there is a lower than normal level of oxygen in your blood system. In such a state the pilot’s flying skills diminish. This condition is particularly insidious because its onset may not be detected by the person flying. As a plane gains altitude, the molecules of oxygen in ambient air get farther apart and exert less pressure per square inch. The resulting partial pressure of oxygen gets lower and the lungs cannot effectively transfer oxygen from the ambient air to the blood to be carried to all tissues in the body.
Charles Lindbergh, who was a college dropout, consciously devoted a significant amount of his time to science[i], as a form of penance for disappointing his mother’s educational goal for him. One of the areas, which caught his interest, was hypoxia. During World War II, he volunteered to be a test object for the Mayo Clinic Aero Medical Unit for Research in Aviation Medicine’s study of this phenomenon. His work included in ten days of a number of tests simulating air pressure at an altitude of 40,000 feet (see picture). The tests proved that the existing procedures were inadequate, that a pilot could be trained to recognize and respond to the conditions and that all pilots with high altitude missions should be taught those lessons in a pressurized chamber.
[i] Lindbergh also worked on creating an artificial heart pump for controversial Dr. Alexi Carrel (for which Carrel won a Nobel Laureate). He also provided support to Dr. Robert Goddard’s successful rocket project.
The current advice to pilots about hypoxia reflects some of Lindbergh’s work with Mayo.
The 711th Human Performance Wing Human Signatures Branch at Wright Patterson Air Force Base commissioned the study of hypoxia biomarkers. As one of the researchers, Dr. Claude Grigsby, said in a press release:
“Despite the myriad of advances in aerospace technology, many modern, high-performance aircraft still rely on the pilot to recognize the symptoms of hypoxia in order to initiate appropriate procedures in the event of a malfunction…This research provides the basis for both the utility of exhaled breath monitoring to monitor for hypoxia as well as targets for future solid state senor development.” [Emphasis added]
Another of the academic team Dr. Sean Harshman added:
“We are working to better understand hypoxic episodes mechanistically to validate our findings and to improve our non-invasive chemical sensing platforms…Our future and ongoing studies seek to confirm the data presented in this manuscript, develop a flight worthy chemical sensor, and begin further mechanistic studies of respiratory hypoxia.”
Adding to the margin of safety is always an important endeavor and here, hypoxia poses such a risk because the potential of its onset can be ignored. As much as the science needs to be advanced, the biomechanics will have to be refined. Pilots may resist an uncomfortable, intrusive sensor.
[ii] UPI’s headline proofreader was asleep when this was approved?Share this article: