High-pressure nervous syndrome

High-pressure nervous syndrome (HPNS – also known as high-pressure neurological syndrome) is a neurological and physiological diving disorder which can result when a diver descends below about 500 feet (150 m) using a breathing gas containing helium. The effects experienced, and the severity of those effects, depend on the rate of descent, the depth and the percentage of helium.[1]

"Helium tremors" were described in 1965 by Royal Navy physiologist Peter B. Bennett.[1][2] Soviet scientist G. L. Zal'tsman first reported on helium tremors in his experiments from 1961. These reports were not available in the West until 1967.[3]

The term high-pressure nervous syndrome was first used by R. W. Brauer in 1968 to describe the combined symptoms of tremor, electroencephalography (EEG) changes, and somnolence that appeared during a 1,189-foot (362 m) chamber dive in Marseille.[4]

  1. ^ a b Bennett, Peter B; Rostain, Jean Claude (2003). "The High Pressure Nervous Syndrome". In Brubakk, Alf O.; Neuman, Tom S (eds.). Bennett and Elliott's physiology and medicine of diving, 5th Rev ed. United States: Saunders. pp. 323–57. ISBN 0-7020-2571-2.
  2. ^ Bennett, P. B. (1965). "Psychometric impairment in men breathing oxygen-helium at increased pressures". Royal Navy Personnel Research Committee, Underwater Physiology Subcommittee Report No. 251. London.
  3. ^ Zal'tsman, G. L. (1967). "Psychological principles of a sojourn of a human in conditions of raised pressure of the gaseous medium (in Russian, 1961)". English Translation, Foreign Technology Division. AD655 360. Wright Patterson Air Force Base, Ohio.
  4. ^ Brauer, R. W. (1968). "Seeking man's depth level". Ocean Industry. 3. London: 28–33.