High pressure nervous syndrome
High pressure nervous syndrome (HPNS) 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 chamber dive in Marseilles.[4]
Symptoms
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
It can be avoided by including small amounts of other gases in the mix, such as nitrogen[8] (creating trimix) or hydrogen[9] (hydreliox)[10].
Drugs
Alcohol, anesthetics and anticonvulsant drugs have had varying results in suppressing HPNS with animals.[1] None are currently in use for humans.
See also
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Brubakk, A. O. (2003). Bennett and Elliott's physiology and medicine of diving, 5th Rev ed. United States: Saunders Ltd. p. 800. ISBN 0702025712. Unknown parameter
|coauthors=ignored (help) - ↑ 2.0 2.1 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. Check date values in:
|date=(help) - ↑ 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. Check date values in:
|date=(help) - ↑ Brauer, R. W. (1968). "Seeking man's depth level". Ocean Industry. London. 3: 28–33. Check date values in:
|date=(help) - ↑ Brauer, R. W. (1968). "Syndrome neurologique et electrographique des hautes pressions". Rev Neurol. Paris. 121 (3): 264–5. PMID 5378824. Unknown parameter
|coauthors=ignored (help); Check date values in:|date=(help) - ↑ Hunger Jr, W. L. (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. Unknown parameter
|coauthors=ignored (help); Check date values in:|date=(help) - ↑ Bennett, P. B. (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. Unknown parameter
|coauthors=ignored (help); Check date values in:|date=(help) - ↑ 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. Check date values in:
|date=(help) - ↑ 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. Check date values in:
|date=(help) - ↑ Rostain, J. C. (1988). "Effects of a H2-He-O2 mixture on the HPNS up to 450 msw". Undersea Biomed. Res. 15 (4): 257–70. ISSN 0093-5387. OCLC 2068005. PMID 3212843. Retrieved 2008-04-07. Unknown parameter
|coauthors=ignored (help); Check date values in:|date=(help)
it:Sindrome nervosa da alta pressione no:Høytrykks nervøst syndrom