[abstract] DYSBARIC OSTEONECROSIS IN UW SHEEP DISSUB STUDY AFTER A 3-HOUR OXYGEN PRE-BREATHE FOLLOWED BY A 1-HOUR AIR BREAK BEFORE DROPOUT DECOMPRESSION.

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[abstract] DYSBARIC OSTEONECROSIS IN UW SHEEP DISSUB STUDY AFTER A 3-HOUR OXYGEN PRE-BREATHE FOLLOWED BY A 1-HOUR AIR BREAK BEFORE DROPOUT DECOMPRESSION.

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Title: [abstract] DYSBARIC OSTEONECROSIS IN UW SHEEP DISSUB STUDY AFTER A 3-HOUR OXYGEN PRE-BREATHE FOLLOWED BY A 1-HOUR AIR BREAK BEFORE DROPOUT DECOMPRESSION.
Author: Sobakin, AS; Lehner, CE; Dueland, RT; Wilson, MA; Gendron-Fitzpatrick, AP; Abraham, JL
Abstract: BACKGROUND: The UW Diving Physiology Laboratory has demonstrated that oxygen pre-breathes (15-min, 1-h, and 2-h) before “drop-out” decompression may reduce DCS morbidity/mortality risk in personnel of disabled submarine (DISSUB). But even a 2-h O2 pre-breathe did not prevent the induction of dysbaric osteonecrosis (DON) in the UW sheep model of the decompressed human. In this study, we investigated the potentially mitigating effect of 3-h oxygen pre-breathing followed by a 1-h air break. MATERIALS AND METHODS: Nine adult female sheep (86-105 kg) underwent dry chamber air exposure at 60 fsw (2.79 atm abs) for 24 hours, followed by an oxygen (88-92%) pre-breathe for 3-h plus a 1-h air break before “dropout” decompression at 30 feet/min (0.9 atm/min) to surface. One month after decompression, we used 99mTc-methylene diphosphonate (MDP) bone scans of radii and tibiae to monitor “hot spots” of remodeling DON lesions. Alizarin complexone fluorochrome was injected IV to visualize DON repair. One week later, sheep underwent necropsy to observe DON pathology. RESULTS: Nine out of 9 animals (100%) survived the provocative “drop-out” decompression. All nine sheep showed frank signs of limb bends. All sheep were ambulatory at four hours and none required early euthanasia. DON developed in all sheep with 100% having bone scan abnormalities indicative of active remodeling typical of DON. The average number of DON lesions per long bone was 2.4 (range 1-4). There were 13 DON lesions observed in the radius (59% of all lesions) and 9 in the tibia. Gross pathology confirmed new bone remodeling repair of DON in bone scan “hot spots.” CONCLUSIONS: This study indicates that 3-h O2 pre-breathing followed by a 1-h air break that emulated submarine escape and rescue did not prevent DON in the decompressed sheep. (Research was funded by NAVSEA, U.S. Navy. We acknowledge the assistance Dr. Ed Flynn.)
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/5144
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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