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Denitrogenation (Preoxygenation) as a Prophylactic Treatment for “Flier's Bends” During High Altitude Missions in Unpressurized Aircraft of the Allied Air Forces in World War II
Author(s) -
Dean Jay B.
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.617.3
Subject(s) - decompression sickness , aeronautics , breathing gas , aviation medicine , medicine , effects of high altitude on humans , breathing , decompression , surgery , anesthesia , engineering , anatomy
Allied aviators flew missions in unpressurized planes to 20,000–30,000 feet and avoided hypoxia by using demand O 2 equipment. With the advent of pressure demand O 2 equipment, the pilot's ceiling was raised to 35,000–47,000 feet! Any mission flown above 20,000 feet increased their risk for decompression sickness (DCS); that is, gases dissolved in their tissues at sea level air pressure would come out of solution at hypobaric pressure to form bubbles (mostly N 2 ) causing pain in the extremities and, in the worse cases, paralysis or death. DCS (aka “Caisson's disease/Diver's bends”) had long been recognized as a serious problem for men who decompressed too quickly from hyperbaric air pressure. “Flier's bends”, however, would not be appreciated until aeronautical engineering developed aircraft capable of flight above 20,000 feet, which finally occurred in the 1930s. Beginning in 1934, Harry Armstrong (Wright Field) would reveal that DCS occurred in men and animals during high altitude “chamber flights”. Armstrong showed in 1940 that 30 min of breathing pure O 2 before ascending to altitude (preoxygenation) reduced both the level of N 2 in the body (denitrogenation) and the risk of DCS. Breathing O 2 for 30–40 min before flight or during ascent to 20,000 feet became standard operating procedure for high altitude missions in WWII. Today, astronauts use preoxygenation prior to extravehicular activity to reduce the risk of DCS.