[abstract] FAILURE OF PREDIVE DENITROGENATION BY OXYGEN BREATHING TO INFLUENCE THE RATE OF NEUROLOGICAL DECOMPRESSION ILLNESS IN PIGS

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[abstract] FAILURE OF PREDIVE DENITROGENATION BY OXYGEN BREATHING TO INFLUENCE THE RATE OF NEUROLOGICAL DECOMPRESSION ILLNESS IN PIGS

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Title: [abstract] FAILURE OF PREDIVE DENITROGENATION BY OXYGEN BREATHING TO INFLUENCE THE RATE OF NEUROLOGICAL DECOMPRESSION ILLNESS IN PIGS
Author: Broome, JR; Buttolph, TB
Abstract: BACKGROUND: Preflight denitrogenation by oxygen breathing is routinely used by military aviators to reduce the risk of hypobaric decompression illness (DCI), but the utility of the technique to reduce the risk of DCI in divers has not been reported. We hypothesized that it could be a particularly useful strategy in deep, short, no-stop, bounce diving. This study investigated the effect of denitrogenation by predive oxygen breathing on the risk of hyperbaric DCI using an established porcine model of neurological DCI. METHODS: Subjects were 20 immature, male, neutered, Yorkshire swine from a closed breeding colony (Wt. 18.3 - 23.7 kg). Before diving, pigs were placed in a specially adapted, gastight transport kennel for 2 h. Once the pig was inside, oxygen was flushed into the kennel at a flow rate of 10 l/min. Within 15 min the kennel atmosphere was greater than 98percent oxygen, and the oxygen flow rate was reduced to 1 l/min for the remaining 1 h 45 min of the prebreathe. After 2 h, pigs were transferred to a standard transport kennel and immediately dived, breathing air. Time from removing the pig from the 100percent oxygen environment to leaving surface was less than 60 s. All pigs were dived on air to 200 fsw in a dry chamber. Bottom time was 24 min, including 5 min compression. Decompression rate was 60 fsw/min. Pigs were observed at surface for signs of neurological DCI. Pigs without neurological signs were assessed as "normal" if they could run on a treadmill without gait disturbance at 1 h postdive. RESULTS: Neurological DCI affected 14 (70percent) of the 20 pigs that breathed oxygen before the dive. This incidence is indistinguishable from the 73.4percent incidence (72/98) of neurological DCI observed in historical control pigs dived on an identical profile. CONCLUSION: We found no evidence that denitrogenation by predive oxygen breathing would be of benefit in reducing the risk of neurological DCI after deep, no-stop air dives. (Supported by NMRDC Work Unit No. M0099.01C-1053).
Description: Undersea and Hyperbaric Medical Society, Inc. (http://www.uhms.org )
URI: http://archive.rubicon-foundation.org/542
Date: 1996

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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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