Idea Transcript
Aviator vs. The Environment: Learning to Protect the Health of the High-Altitude Aviator during World War II Jay B. Dean, Ph.D., Professor, Dept. of Molecular Pharmacology & Physiology, Hyperbaric Biomedical Research Laboratory, College of Medicine, University of South Florida, Tampa, FL 33612 ABSTRACT. The air war of 1939-45 was a physiological war. Aviators flew non-pressurized planes to altitudes of 20,000-35,000 feet during long-range reconnaissance and bombing missions in order to evade enemy interceptors and anti-aircraft fire. Above 20,000 feet, aircrew performance was often impaired by hypoxia, decompression sickness (DCS), and hypothermia. Escaping from a disabled aircraft at high-altitude presented numerous physiological challenges to safe escape, including hypoxia, frostbite and the opening shock of the parachute (see photo inset). The “Nemesis of Aeroembolism” was the high-altitude B-17E research platHigh-performance fighter aircraft subjected alform for the Wright Field Aero Medical Laboratory during WWII (Dayton, lied pilots to tremendous centrifugal forces durOH). Nemesis was used to test prototypes of O2 breathing equipment and ing violent dog-fighting maneuvers that would insulated flight suits, and for studies of the aviator’s physiology at extreme leave them temporarily blinded and unconscious altitude and cold. Stripped of excess weight, Nemesis achieved altitudes in due to a reduction in brain blood flow. America excess of 40,000 feet, which necessitated O2-pressure breathing masks bewould deploy its first pressurized bomber in the cause the fuselage was non-pressurized. This photograph shows the Nemesis of Aeroembolism in 1943 as she prepares to go aloft in a study of the openspring of 1944 (B-29 Superfortress) in the Pacifing shock of a parachute at high-altitude. The test subject is “Major” St. ic war to alleviate the physiological problems Bernard (front row, 2nd from right). Major was a veteran parachute pup; his caused by reduced barometric pressure and cold. highest static line drop was made from 26,000 feet. Notice Major’s oxygen Pressurized flight, however, created a new probmask and parachute to his right. (Mayo Clinic Archives) lem; namely, it was unknown how aircrews would respond to explosive decompression at high-altitude following structural failure of their pressure cabin. If they survived decompression at 35,000 feet, how long did they have to don their oxygen masks before succumbing to hypoxia? Would the incidence of DCS increase? What were the physical forces during rapid decompression; specifically, was the ensuing wind blast during decompression great enough to inflict physical injury? Pioneering research on the physiologic effects of high-altitude and explosive decompression was conducted at the Aero Medical Laboratory at Wright Field in Dayton, Ohio, and several of the countries leading universities. Beginning with only 3 research laboratories in 1940, the nation’s research program for high-altitude physiology would grow over the course of the war, such that it was without equal in the world by 1945 for providing protective flying equipment and training for allied aviators. By 1945, the high-altitude training program employed over 200 aviation physiologists running 65 altitude chambers at 45 Army airfields who indoctrinated more than 58,000 men per month in the physiologic effects of high altitude flight. Allied aviators were taught many procedures such as O2 discipline; prevention of DCS with 100% O2-prebreathing; appropriate use of bail-out O2 equipment in a high-altitude/low-opening parachute jump, which was necessary to avoid the opening shock of the parachute and to prevent hypoxia; use of the G-suit, which enabled pilots to withstand greater G-forces, and consequently to outperform their adversary in a dog-fight; and how to survive an explosive decompression. The successful aeromedical research and training programs established by these pioneering “physiological warriors” played a significant role in the Allies’ air victory in the air war. The knowledge gained and the new practices established during the war years would propel the aviator into the jet age and lay the scientific foundation for space medicine in the post-war era. During the presentation, Dr. Dean will present archival photographs and film footage, much of which has never been published, from the original technical reports of the Wright Field Aero Medical Lab and the Ohio State University Laboratory of Aviation Physiology. Enjoy!