Development of a Decompression Algorithm for Constant 0.7 ATA Oxygen Partial Pressure in Helium Diving.

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Development of a Decompression Algorithm for Constant 0.7 ATA Oxygen Partial Pressure in Helium Diving.

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Title: Development of a Decompression Algorithm for Constant 0.7 ATA Oxygen Partial Pressure in Helium Diving.
Author: Thalmann, ED
Abstract: A total of 1582 man dives were done to test a computer algorithm used to compute decompression schedules for a closed circuit underwater breathing apparatus which maintains a constant 0.7 ATA PO2 in a helium diluent. The 47 test dives were all single depth dives up to 300 FSW deep with total dive times approaching 4 hours. The first three phases of testing resulted in a computer algorithm which appeared initially safe but which subsequently produced an unacceptably high incidence of decompression sickness (DCS) on a later dive series. Investigation of this high incidence of DCS on later dives lead to the identification of a workup phenomenon which showed that previous HeO2 diving will significantly reduce individual susceptibility to DCS. Further testing resulted in a computer algorithm which would compute safe decompression schedules for divers who are not worked up. The overall raw incidence of DCS for the entire dive series was 3.73% with 37% of all symptoms being Type 2. The overall incidence of DCS was 3% lower than that found during testing of a similar computer algorithm using a constant 0.7 ATA PO2 and a nitrogen diluent but the proportion of Type 2 DCS was higher using a helium diluent than when using a nitrogen diluent.
Description: Citation Status: Active; Citation Classification: Unclassified; Title Classification: Unclassified; Report Classification: Unclassified; Identifier Classification: Unclassified; Abstract Classification: Unclassified; Distribution Limitation(s): 01 - APPROVED FOR PUBLIC RELEASE; Information provided by the Department of Defense and the Defense Technical Information Center (http://www.dtic.mil/) is considered public information and may be distributed or copied unless otherwise specified. Use of appropriate byline/photo/image credits is requested.
URI: http://archive.rubicon-foundation.org/4816
Date: 1985

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