[abstract] 15 AND 45 MINUTES OF OXYGEN PRE-BREATHE SIGNIFICANTLY REDUCES SEVERE DECOMPRESSION ILLNESS AFTER SATURATION DROPOUT IN 70 KG SWINE.

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[abstract] 15 AND 45 MINUTES OF OXYGEN PRE-BREATHE SIGNIFICANTLY REDUCES SEVERE DECOMPRESSION ILLNESS AFTER SATURATION DROPOUT IN 70 KG SWINE.

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Title: [abstract] 15 AND 45 MINUTES OF OXYGEN PRE-BREATHE SIGNIFICANTLY REDUCES SEVERE DECOMPRESSION ILLNESS AFTER SATURATION DROPOUT IN 70 KG SWINE.
Author: Mahon, RT; Dainer, HM; Soutiere, SE; Steinbach, T
Abstract: BACKGROUND: Breathing 100% O2 prior to decompression reduces the incidence of altitude decompression illness (DCI). Similarly, we have previously demonstrated that an isobaric oxygen prebreathe (OPB) of 1 h will eliminate lethal DCI. However, the use of OPB < 1 h has not been studied in the hyperbaric environment. This study reports the results of OPB of < 1 h in a swine model of saturation at 2.8 ATA (60 fsw) followed by rapid decompression to surface. MATERIALS AND METHODS: Unrestrained, catheterized, male Yorkshire swine (68.5 kg +/-2.4kg) were placed in individual Plexiglas boxes within a large animal hyperbaric chamber. The chamber was compressed with air to 2.8 ATA for 22 h. Following saturation and while still at depth, gas to the boxes was remotely switched so that the animals received either 1) 45 min O2 pre-breathe; 2) 15 min O2 pre-breathe, or 3) no O2 pre-breathe (control) prior to rapid decompression (0.91 ATA/min) to surface. Animals were then observed for signs of DCI. Animals with severe DCI (cardiopulmonary or neurologic) were euthanized and sent for necropsy. Animals without severe DCI were observed for 6 days and then underwent necropsy. The lungs were inflated with 1.5% agarose in isotonic saline, fixed, and counterstained with H and E. RESULTS: 45 min of OPB at 2.8 ATA eliminated severe DCI from saturation dropout. DCI was reduced from 73% (8/11) in control animals to 8% (1/13) with 15 min OPB. Both periods of OPB represent a statistically significant improvement (p<0.0001) over no OPB. OPB also resulted in significant decreases in cutis marmorata (p<0.0005). No evidence of lung histopathologic abnormalities was observed in swine that did not suffer from DCI. CONCLUSIONS: OPB of 15 and 45 minutes significantly reduces severe DCI following dropout decompression from saturation at 2.8 ATA in 70 kg swine. These results demonstrate that even very short periods of OPB could be expected to improve outcome in a disabled submarine scenario. (Supported by NAVSEA Work unit number 603713N.84C.A0606.)
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/5149
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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