[abstract] DIFFERENCE IN BUBBLE FORMATION USING DEEP STOPS IS DEPENDENT ON LENGTH OF BOTTOM TIME; EXPERIMENTAL FINDINGS AND THEORETICAL SUPPORT.

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[abstract] DIFFERENCE IN BUBBLE FORMATION USING DEEP STOPS IS DEPENDENT ON LENGTH OF BOTTOM TIME; EXPERIMENTAL FINDINGS AND THEORETICAL SUPPORT.

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Title: [abstract] DIFFERENCE IN BUBBLE FORMATION USING DEEP STOPS IS DEPENDENT ON LENGTH OF BOTTOM TIME; EXPERIMENTAL FINDINGS AND THEORETICAL SUPPORT.
Author: Gutvik, CR; Møllerløkken, A; Brubakk, AO
Abstract: BACKGROUND: Deep decompression stops compared to more conventional shallower stops have recently been introduced. Most findings and theoretical work on excess gas phase models suggest an apparent advantage of using deeper stops. However, some reports indicate that the incidence and/or risk of decompression sickness may actually increase following such procedures. MATERIALS AND METHODS: The impact of different decompression schedules was tested on pigs compressed in a dry chamber monitored using ultrasonic imaging. A total of 26 pigs were divided into 4 groups of 6 and one group of 2 (aborted protocol). Two groups performed a shallow/long (30 msw / 70 min) dive. One group followed a Bühlmann / Uwatec decompression procedure while the other followed a procedure generated by the Copernicus bubble model. The three last groups did a deep/short (65 msw / 20 min) dive followed by a Bühlmann decompression procedure, a Copernicus procedure (aborted profile) and a revised Copernicus procedure respectively. RESULTS: The long/shallow dive achieved a significant decrease of vascular bubbles following the procedure with deeper initial stops (Copernicus schedule) compared to the controls (Bühlmann schedule). However, on the deep/short dive the procedure with deeper stops gave a dramatic increase of bubble formation, resulting in the protocol to be aborted after two trials. A new revised Copernicus schedule with the deepest stops removed, gave a significant decrease of vascular bubble formation. CONCLUSIONS: A new stabilizing mechanism for bubble nuclei had to be developed in order to simulate and reproduce the findings in this study. “Traditional” bubble models will in general suggest that adding some deep stops is beneficial for decompression outcome, however this may not always be true. The presented studies suggest that deep stops are not recommended on shorter dives.
Description: Abstract of the Undersea and Hyperbaric Medical Society, Inc. Annual Scientific Meeting held June 14-16, 2007. Ritz-Carlton Kapalua Maui, Hawaii (http:www.uhms.org)
URI: http://archive.rubicon-foundation.org/5067
Date: 2007

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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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