On the likelihood of decompression sickness during H2 biochemical decompression in pigs

• Published in: Journal of applied physiology (1985) 2001-12, Vol.91 (6), p.2720-2729
• Main Authors: Fahlman, Andreas, Tikuisis, Peter, Himm, Jeffrey F, Weathersby, Paul K, Kayar, Susan R
• Format: Article
• Language: English
• Subjects: Biochemistry; Biological and medical sciences; Hogs; Hydrogen; Medical sciences; Transport. Aerospace. Diving. Altitude; Traumas. Diseases due to physical agents
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/jappl.2001.91.6.2720

1  Environmental Physiology Department, Naval Medical Research Center, Silver Spring, Maryland 20910-7500; and 2  Defence and Civil Institute of Environmental Medicine, Toronto, Ontario, Canada M3M 3B9 A probabilistic model was used to predict decompression sickness (DCS) outcome in pigs during exposures to hyperbaric H 2 to quantify the effects of H 2 biochemical decompression, a process in which metabolism of H 2 by intestinal microbes facilitates decompression. The data set included 109 exposures to 22-26 atm, ca. 88% H 2 , 9% He, 2% O 2 , 1% N 2 , for 0.5-24 h. Single exponential kinetics described the tissue partial pressures (Ptis) of H 2 and He at time t : Ptis =   (Pamb   Ptis) ·  1 d t , where Pamb is ambient pressure and  is a time constant. The probability of DCS [ P (DCS)] was predicted from the risk function: P (DCS) = 1    e r , where r  =   (Ptis H 2  + Ptis H e    Thr   Pamb) · Pamb 1 d t , and Thr is a threshold parameter. Inclusion of a parameter ( A ) to estimate the effect of H 2 metabolism on P (DCS): Ptis H 2   =   (Pamb    A    Ptis H 2 ) ·  1 d t , significantly improved the prediction of P (DCS). Thus lower P (DCS) was predicted by microbial H 2 metabolism during H 2 biochemical decompression. probabilistic modeling; Sus scrofa ; hydrogen diving; H 2 metabolism; Methanobrevibacter smithii