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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 - 2009
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.23.1_supplement.597.3
Subject(s) - decompression sickness , breathing , effects of high altitude on humans , aeronautics , air travel , medicine , surgery , anesthesia , aviation , decompression , aerospace engineering , engineering , anatomy
Allied bombing missions in unpressurized planes required O 2 ‐breathing at 20,000‐30,000 ft. By using pressure breathing (e.g. photo reconnaissance missions), altitudes of 35,000‐47,000 ft were endured. Any flight > 20,000 ft increased the airman's risk for decompression sickness (DCS); that is, gases dissolved in their tissues at sea level would come out of solution at hypobaric pressure and form bubbles (mostly N 2 ) causing pain in the extremities and, in the worse cases, paralysis or death. DCS‐aka "Caisson's disease" or "Diver's bends"‐had been recognized since the 1840s as a serious problem for men who decompressed too quickly from hyperbaric air pressure. "Flier's bends" was not appreciated until aeronautical engineering developed aircraft capable of flight above 20,000 feet in the 1930s. Beginning in 1934, Harry Armstrong (Wright Field) revealed that DCS occurred in men and animals during high altitude "chamber flights". Armstrong, Randy Lovelace (Mayo Clinic) and others reported in 1940‐41 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 slow ascent to 20,000 feet, became standard operating procedure for high altitude missions in WWII. Today, astronauts undergo denitrogenation prior to a "space walk" to reduce their risk of DCS.