[abstract] PDIS: PROFILE - DEPENDENT INTERMEDIATE STOP.

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[abstract] PDIS: PROFILE - DEPENDENT INTERMEDIATE STOP.

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Title: [abstract] PDIS: PROFILE - DEPENDENT INTERMEDIATE STOP.
Author: Angelini, S
Abstract: INTRODUCTION: In recent times, deep stops have become quite popular amongst divers of all levels. The conventional deep stop is carried out at half of the max depth for no stop dives, and at half the distance between the max depth and the depth of the first decompression stop for decompression dives. It has been argued whether such stops are beneficial and, if so, under what circumstances. We propose an optimized “intermediate” depth for a stop, which accounts for the details of the dive profile itself, repetitive dives and nitrox. METHODS: PDIS is embedded in the Bühlmann - based UWATEC ZH-L8 ADT, with half times between 5 and 640 minute. The calculated depth is that at which the leading compartment in the decompression calculation, excluding however the 5 and 10 minute compartments, switches from ongassing to offgassing. This ensures that, within the underlying Haldanian logic, at the prescribed depth: - at least three compartments are offgassing, of which 2 (5 and 10 minute half times) under a relatively high pressure gradient; - for decompression dives, the existing obligation is not increased during the stop. RESULTS: We analyze dives to various depths, and describe how the PDI stop evolves during a dive and how it compares to the conventional deep stop. The table shows a partial summary for square profiles on air. <table>Dive depth Bottom time Leading Tissue Tissue used for PDIS PDIS depth “Conventional” deep stop Notes; 30m 10min 5min 20min 10m 15m; 30m 14min 10min 20min 13m 15m; Rep30m 5min 40min 40min 9m 15m At 15m all tissues are ongassing</table> CONCLUSIONS: Within a Haldanian logic, for certain dive profiles conventional deep stops do not show any benefits. The PDI stop, on the other hand, provides the benefit of offgassing under a relatively high ambient pressure.
Description: Abstract of the Undersea & Hyperbaric Medical Society 2008 Annual Scientific Meeting June 26-28, 2008 Salt Lake City Marriott Downtown, Salt Lake City, Utah.
URI: http://archive.rubicon-foundation.org/7801
Date: 2008

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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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