The Full Wiki

High pressure nervous syndrome: Wikis


Note: Many of our articles have direct quotes from sources you can cite, within the Wikipedia article! This article doesn't yet, but we're working on it! See more info or our list of citable articles.


From Wikipedia, the free encyclopedia

High Pressure Nervous Syndrome (HPNS - also known as High Pressure Neurological Syndrome) is a neurological and physiological diving disorder that results when a diver spends too much time breathing a high-pressure mixture of helium and oxygen (heliox).[1] HPNS is a limiting factor in future deep diving.

"Helium tremors" were first described in 1965 by Royal Navy physiologist Peter B. Bennett, who also founded the Divers Alert Network.[1][2] Zal'tsman also reported on helium tremors in his experiments from 1961. Unfortunately these reports were not available in the west until 1967.[3]

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



Symptoms of HPNS include tremors, myoclonic jerking, somnolence, EEG changes[5], visual disturbance, nausea, dizziness, and decreased mental performance.[1][2]

The susceptibility of divers and animals to HPNS does depend on the individual.[1]

Suppressive Measures

It is not likely that HPNS can be prevented entirely but there are effective methods to delay or change the development of the symptoms.[1][6]

Rate of Compression

Utilizing slow rates of compression or adding stops to the compression have been found to prevent large initial decrements in performance.[1][7]

Breathing Mixture

Including other gases in the mix, such as nitrogen (creating trimix) or hydrogen (hydreliox) suppresses the neurological effects.[8][9][10]


Alcohol, anesthetics and anticonvulsant drugs have had varying results in suppressing HPNS with animals.[1] None are currently in use for humans.

See also


  1. ^ a b c d e f g Brubakk, A. O.; T. S. Neuman (2003). Bennett and Elliott's physiology and medicine of diving, 5th Rev ed.. United States: Saunders Ltd.. p. 800. ISBN 0702025712.  
  2. ^ a b 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 (London) 3: 28–33.  
  5. ^ Brauer, R. W.; S. Dimov; X. Fructus; P. Fructus; A. Gosset; R. Naquet. (1968). "Syndrome neurologique et electrographique des hautes pressions". Rev Neurol (Paris) 121 (3): 264–5. PMID 5378824.  
  6. ^ Hunger Jr, W. L.; P. B. Bennett. (1974). "The causes, mechanisms and prevention of the high pressure nervous syndrome". Undersea Biomed. Res. 1 (1): 1–28. ISSN 0093-5387. OCLC 2068005. PMID 4619860. Retrieved 2008-04-07.  
  7. ^ Bennett, P. B.; R. Coggin; M. McLeod. (1982). "Effect of compression rate on use of trimix to ameliorate HPNS in man to 686 m (2250 ft)". Undersea Biomed. Res. 9 (4): 335–51. ISSN 0093-5387. OCLC 2068005. PMID 7168098. Retrieved 2008-04-07.  
  8. ^ Vigreux, J. (1970). "Contribution to the study of the neurological and mental reactions of the organism of the higher mammal to gaseous mixtures under pressure". MD Thesis (Toulouse University).  
  9. ^ Fife, W. P. (1979). "The use of Non-Explosive mixtures of hydrogen and oxygen for diving". Texas A&M University Sea Grant TAMU-SG-79-201.  
  10. ^ Rostain, J. C.; Gardette-Chauffour, M. C.; Lemaire, C.; Naquet, R. (1988). "Effects of a H2-He-O2 mixture on the HPNS up to 450 msw". Undersea Biomedical Research 15 (4): 257–70. ISSN 0093-5387. OCLC 2068005. PMID 3212843. Retrieved 2008-04-07.  

Got something to say? Make a comment.
Your name
Your email address