[abstract] DOPPLER BUBBLE MEASUREMENTS AND DECOMPRESSION SICKNESS

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[abstract] DOPPLER BUBBLE MEASUREMENTS AND DECOMPRESSION SICKNESS

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Title: [abstract] DOPPLER BUBBLE MEASUREMENTS AND DECOMPRESSION SICKNESS
Author: Vann, RD; Dick, AP; Barry, PD
Abstract: Two series of subsaturation decompression trials have been analyzed to assess the practical value of precordial doppler bubble grade measurements. In 286 nitrogen-oxygen dives at Duke, doppler readings were taken from prone divers exercising each limb in turn. In 166 air dives at DCIEM (Reports 80-R-32 & 81-R-02), readings were taken from divers standing at rest and after a deep knee bend. Duke used Spencer's bubble grading scale (JAP 4:229, 1976) while DCIEM used a modified form of this scale. Despite dissimilar procedures, both studies had similar results. Mean bubble grades were calculated for dives on which decompression sickness (DCS) occurred and for DCS-free dives. The differences were highly significant with the higher bubble grades having greater probabilities of DCS. Grades 0 to 2 had probabilities of 3% or less. Grade 3 had a probability of 9 to 18% and grade 4 a probability of 20 to 50%. It is concluded that a post dive bubble grade of 3 or 4 is not of predictive value although it may justify closer observation of a diver. Precordial doppler measurements may be more useful in the development of subsaturation decompression schedules. The binomial theorem shows that statistical confidence in a decompression schedule is not achieved in less than 60 DCS-free dives. It may be possible to reduce this number by rejecting schedules which give bubble grades of 3 or 4 even in the absence of DCS. This is offered as an hypothesis for testing.
Description: Abstract of the Undersea and Hyperbaric Medical Society, Inc. Annual Scientific Meeting held June 1-5,1982 in Norfolk, Virginia (http:www.uhms.org).
URI: http://archive.rubicon-foundation.org/6054
Date: 1982

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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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