[abstract] SUPPRESSION OF THE HIGH PRESSURE NERVOUS SYNDROME (HPNS) IN HUMAN DIVES TO 720 FT. AND 1000 FT. BY USE OF N2/He/02.

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[abstract] SUPPRESSION OF THE HIGH PRESSURE NERVOUS SYNDROME (HPNS) IN HUMAN DIVES TO 720 FT. AND 1000 FT. BY USE OF N2/He/02.

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Title: [abstract] SUPPRESSION OF THE HIGH PRESSURE NERVOUS SYNDROME (HPNS) IN HUMAN DIVES TO 720 FT. AND 1000 FT. BY USE OF N2/He/02.
Author: Bennett, PB; Blenkarn, GD; Roby, J; Youngblood, D
Abstract: During August-September 1973, 4 subjects from Harbor Branch and Oceaneering Inc., Houston were compressed in the Duke Hyperbaric Facility to 720 ft. in 17 mins. (plus 3 mins. for stages) for 1 hour breathing 25% N2/ 75% He with 0.5 ATA 02 and the result compared with dives to 200 ft. (air) and 720 ft. (He/O2). Measurements were made of EEG, tremor, psychomotor and intellectual performance, subjective appreciation, pulmonary function, voice communication. Decompression with 0.8 ATA 02 was in 3 days. The same men in November-December 1973 were exposed in 27 mins (plus 6 mins. for stages) to 1000 ft. with trimix (18% N2), heliox and to 200 ft. (air). Decompression after 1 hour at 1000 ft. was in 4 days. The presence of N2 suppressed the tremors completely compared with He/ 02. Psychomotor tests showed an improvement and the nausea and dizziness stopped. Some decrement in performance, especially intellectual, was still present with trimix due to nitrogen narcosis. Reduction to 18% N2 at 1000 ft. also caused narcosis but controlled the HPNS. Compression arthralgia was reduced with trimix. The EEG showed reduced activity with air but similar augmentation with He/O2 and He/N2/02. Visual evoked potentials were unaffected. Subjectively, two subjects favored He/N2/O2 and these were especially sensitive to HPNS. The other two were not HPNS sensitive and found the nitrogen narcosis in He/N2/O2 more decremental than diving on He/O2. Pulmonary function tests showed a -4.62% FVC and +7.4 torr in A-a gradient post-dive. Signs of pulmonary toxicity occurred in the first 24 hours of decompression but disappeared the next day. Thus N2 suppressed signs and symptoms of HPNS but the N2 partial pressure was too high in the present dives resulting in unnecessary narcosis.
Description: Abstract of the Undersea and Hyperbaric Medical Society, Inc. Annual Scientific Meeting held May 10-11, 1974. Hilton Hotel, Washington, D.C. (http:www.uhms.org)
URI: http://archive.rubicon-foundation.org/28
Date: 1974

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  • UHMS Meeting Abstracts
    This is a collection of the published abstracts from the Undersea and Hyperbaric Medical Society (UHMS) annual meetings.

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