Varying Permeability Model

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The Variable Permeability Model or VPM is a decompression algorithm that was developed by D.E. Yount and others for use in commercial and recreational diving. It was developed to model laboratory observations of bubble formation and growth in both inanimate and in vivo systems exposed to pressure. In 1986, this model was applied by researchers at the University of Hawaii to calculate diving decompression tables.

The VPM presumes that microscopic bubble nuclei always exist in water and tissues that contain water. Any nuclei larger than a specific "critical" size, which is related to the maximum dive depth (exposure pressure), will grow upon decompression (when the diver ascends again). The VPM aims to minimize the total volume of these growing bubbles by keeping the external pressure large, and the inspired inert gas partial pressures low during decompression.

[edit] References

[edit] Primary Modeling References

  • Yount, D.E. and Hoffman, D.C. 1984. Decompression theory: A dynamic critical-volume hypothesis. In: Bachrach A.J. and Matzen, M.M. eds. Underwater physiology VIII: Proceedings of the eighth symposium on underwater physiology. Undersea Medical Society, Bethesda, 131-146.
  • Yount, D.E. and Hoffman, D.C. 1986. On the use of a bubble formation model to calculate diving tables. Aviat. Space Environ. Med. 57:149-156.
  • Yount, D.E. and Hoffman, D.C. 1989. On the use of a bubble formation model to calculate nitrogen and helium diving tables. In: Paganelli, C.V. and Farhi, L.E. eds. Physiological functions in special environments. Springer-Verlag, New York, 95-108.
  • Yount, D.E., Maiken, E.B., and Baker, E.C. 2000. Implications of the Varying Permeability Model for Reverse Dive Profiles. In: Lang, M.A. and Lehner, C.E. (eds.). Proceedings of the Reverse Dive Profiles Workshop. Smithsonian Institution, Washington, D.C. pp. 29-61.

[edit] VPM Research and Development References

  • D’Arrigo, J.S. 1978. Improved method for studying the surface chemistry of bubble formation. Aviat. Space Environ. Med. 49:358-361.
  • Kunkle, T.D. 1979. Bubble nucleation in supersaturated fluids. Univ. of Hawaii Sea Grant Technical Report UNIHI-SEAGRANT-TR-80-01. Pp. 108.
  • Paganelli, C.V., Strauss, R.H., and Yount, D.E. 1977. Bubble formation within decompressed hen’s eggs. Aviat. Space Environ. Med. 48:48-49.
  • Strauss, R.H. 1974. Bubble formation in gelatin: Implications for prevention of decompression sickness. Undersea Biomed. Res. 1:169-174.
  • Strauss, R.H. and Kunkle, T.D. 1974. Isobaric bubble growth: A consequence of altering atmospheric gas. Science. 186:443-444.
  • Yount, D.E. and Kunkle, T.D. 1975. Gas nucleation in the vicinity of solid hydrophobic spheres. Journal of Applied Physics. 46:4484-4486.
  • Yount, D.E. and Strauss, R.H. 1976. Bubble formation in gelatin: A model for decompression sickness. J. Appl. Phys. 47:5081-5089.
  • Yount, D.E., Kunkle, T.D., D’Arrigo, J.S., Ingle, F.W., Yeung, C.M., and Beckman, E.L. 1977. Stabilization of gas cavitation nuclei by surface-active compounds. Aviat. Space Environ. Med. 48:185-191.
  • Yount, D.E. 1979. Skins of varying permeability: a stabilization mechanism for gas cavitation nuclei. J. Acoust. Soc. Am. 65:1429-1439.
  • Yount, D.E., Yeung, C.M., and Ingle, F.W. 1979. Determination of the radii of gas cavitation nuclei by filtering gelatin. J. Acoust. Soc. Am. 65:1440-1450.
  • Yount, D.E. 1979. Application of a bubble formation model to decompression sickness in rats and humans. Aviat. Space Environ. Med. 50:44-50.
  • Yount, D.E. 1979. Multiple inert-gas bubble disease: a review of the theory. In: Lambertsen, C.J. and Bornmann, R.C. eds. Isobaric Inert Gas Counterdiffusion. Undersea Medical Society, Bethesda, 90-125.
  • Yount, D.E. and Lally, D.A. 1980. On the use of oxygen to facilitate decompression. Aviat. Space Environ. Med. 51:544-550.
  • Yount, D.E. 1981. Application of a bubble formation model to decompression sickness in fingerling salmon. Undersea Biomed. Res. 8:199-208.
  • Yount, D.E. and Yeung, C.M. 1981. Bubble formation in supersaturated gelatin: a further investigation of gas cavitation nuclei. J. Acoust. Soc. Am. 69:702-708.
  • Yount, D.E. 1982. On the evolution, generation, and regeneration of gas cavitation nuclei. J.Acoust. Soc. Am. 71:1473-1481.
  • Yount, D.E. and Hoffman, D.C. 1983. On the use of a cavitation model to calculate diving tables. In: Hoyt, J.W., ed. Cavitation and multiphase flow forum-1983. New York: American Society of Mechanical Engineers, 65-68.
  • Yount, D.E. 1983. A model for microbubble fission in surfactant solutions. J. Colloid and Interface Science 91:349-360.
  • Yount, D.E., Gillary, E.W., and Hoffman, D.C. 1984. A microscopic investigation of bubble formation nuclei. J. Acoust. Soc. Am. 76:1511-1521.
  • Yount, D.E. 1997. On the elastic properties of the interfaces that stabilize gas cavitation nuclei. J. Colloid and Interface Science 193:50-59.
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