Deep diving and short decompression by breathing mixed gases

Keller, Hans-Rudolf; Bühlmann, A

doi:10.1152/jappl.1965.20.6.1267

Cited by 30 publications

(10 citation statements)

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“…1 These differences in half-times represent faster tissue:blood equilibration of helium than of nitrogen. Faster tissue:blood equilibration of helium than of nitrogen will occur in tissues where the tissue solubility of helium is lower than that of nitrogen, and will also occur, owing to the higher diffusivity of helium than of nitrogen, in regions where tissue:blood equilibration is diffusion-limited.…”

Section: Discussionmentioning

confidence: 99%

“…Instead, a mixture of helium and oxygen (heliox) is usually breathed for dives deeper than 150 feet sea water (fsw), because helium is not narcotic and is less dense than nitrogen. However, a longer decompression obligation is thought to accrue during a heliox bounce dive than during a nitrox bounce dive 1 (a bounce dive is one of insufficient duration for the body to completely equilibrate with inspired inert gas partial pressures). If this difference in decompression requirements for heliox and nitrox is real, breathing a helium-nitrogen-oxygen mixture (trimix) for moderately deep bounce dives may have the advantage of reducing nitrogen narcosis and work of breathing compared to breathing nitrox, but result in less decompression obligation than breathing heliox.…”

Section: Introductionmentioning

confidence: 99%

“…In this case, slower uptake of nitrogen than helium into modelled compartments can result in less decompression obligation prescribed for a dive conducted breathing nitrox or trimix compared to a dive conducted breathing heliox. 1 It is not clear whether there is a real difference in decompression requirements for nitrox and heliox bounce dives. The few human data comparing nitrox and heliox dives to the same depth are conflicting, and do not provide compelling evidence of a difference in decompression requirement.…”

Section: Introductionmentioning

confidence: 99%

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DECOMPRESSION FROM He-N2-O2 (TRIMIX) BOUNCE DIVES IS NOT MORE EFFICIENT THAN FROM He-O2 (HELIOX) BOUNCE DIVES

Doolette¹,

Gault²,

Gerth³

2015

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY)28-05-2015 REPORT TYPE Technical Report DATES COVERED (From -To) SPONSOR/MONITOR'S REPORT NUMBER(S)12. DISTRIBUTION / AVAILABILITY STATEMENT Distribution Statement A: Approved for public release; distribution is unlimited. SUPPLEMENTARY NOTES ABSTRACTHeliox (He-O2) enables diving deeper than limits imposed by breathing N2-O2, but heliox has some costs, and several navies have pursued a trimix (He-N2-O2) diving capability as an alternative to heliox. It is widely believed that trimix bounce dives can be conducted with substantially reduced decompression times than corresponding heliox dives. If this were true, trimix would be an attractive alternative to heliox for U. S. Navy MK 16 MOD 1 underwater breathing apparatus (UBA) diving. However, there is no direct evidence of greater decompression efficiency of trimix than of heliox. Decompression efficiency was assessed by comparing the incidence of decompression sickness (DCS) following decompression dives using MK 16 MOD 1 UBAs (1.3 atm PO2 set point) with either heliox (88% He / 12% O2) or trimix (44% He / 44% N2 / 12% O2) diluent. Both trimix and heliox dives followed the identical depth/time schedule (200 fsw for 40 minutes bottom time followed by 119 minutes of decompression stops). This schedule was selected for having the largest difference in estimated probabilities of DCS between trimix and heliox among a range of candidate schedules that were practicable to man-test and operationally relevant. The trial ended at an interim stopping criterion with fifty man-dives completed on the heliox schedule with no diagnosed incidents of DCS, and forty-six man dives completed on the trimix schedule with two diagnosed incidents of DCS. The null hypothesis was retained: decompression from trimix bounce dives is not more efficient than decompression from heliox bounce dives. Potential disadvantages of heliox with respect to cost, thermal balance, and voice communications are of limited relevance to MK 16 MOD 1 diving. In the absence of any decompression advantage, trimix is not an attractive alternative to heliox for U. S. Navy MK 16 MOD 1 or other c...

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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DECOMPRESSION FROM He-N2-O2 (TRIMIX) BOUNCE DIVES IS NOT MORE EFFICIENT THAN FROM He-O2 (HELIOX) BOUNCE DIVES

Doolette¹,

Gault²,

Gerth³

2015

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“…Il a été suggéré de remplacer l'azote dans le gaz de respiration ou de décompres-sion par de l'argon, pour accélérer l'élimination de l'azote dissous dans le sang [48]. Un tel mélange porte le nom d'Argox ou d'Argonox, en écho au Nitrox, mélange de plongée azote/oxygène, où l'oxygène est en plus grande proportion que dans l'air.…”

Section: Argon Et Accidents De Plongéeunclassified

L’argon : utilisations, toxicité et stratégie analytique en toxicologie médicolégale

2012

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Résumé -Bien qu'intrinsèquement non toxiques, les gaz nobles comme l'argon entraînent à fortes concentrations une déplétion d'oxygène pouvant mener jusqu'à l'asphyxie. Si l'argon se retrouve dans la circulation générale, celui-ci peut même être responsable d'embolies parfois fatales. Cependant, les propriétés d'inerties physicochimiques de ce gaz le rendent très utile dans de nombreuses applications actuelles. Ces applications étant en constante augmentation, il n'est pas rare d'observer proportionnellement des intoxications parfois létales liées à ce gaz. Ainsi, devant le manque d'harmonisation des prélèvements d'échantillons biologiques afin de mettre en évidence de telles intoxications aux gaz nobles et devant l'augmentation du nombre de cas, il devient nécessaire d'établir un état des lieux sur l'utilisation de l'argon, sa toxicité et la stratégie analytique à adopter dans le contexte médico-légal. Mots clés :Argon, gaz noble, échantillonnage de gaz, analyse de gaz Abstract -Even though noble gases such as argon are intrisically non-toxic, they will enhance an oxygen-depletion at high concentrations. This depletion may lead to asphyxia. If argon is found in blood flow, it could be responsible of an embolism. However, its inert physicochemical properties appear to be very useful to a wide range of current applications. The rise of these applications induces a proportionnal increase of lethal intoxications due to this gas. Thus, as no standardization of biological samples exists, and knowing the increase of argon intoxication cases, it seems necessary to establish an incoming inventory of fixture concerning the use of argon. It will confirm its toxicity properties and will highlight other intoxications due to noble gas. This should lead to a new analytical strategy suitable to the forensic context.

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“…The profile information requested is simple: [35,40,[44][45][46]. Isobaric counterdiffusion refers to two inert gases (usually nitrogen and helium) moving in opposite directions in tissues and blood.…”

Section: Lanl Profile Data Bankmentioning

confidence: 99%

On Validation of a Popular Sport Diving Decompression Model

Wienke¹

2009

TOSSJ

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Linking deep stop model and data, we detail the LANL reduced gradient bubble model (RGBM), dynamical principles, and correlation with the LANL Data Bank. Table, profile, and meter risks are obtained from likelihood analysis, and pertinent applications include nonstop air diving, the Bennett and Maronni 2.5 minute recreational deep stop, C & C Team 450/20 multiple RB dive sequence at 1.4 atm, NEDU deep stop tests, and French Navy deep stop profiles. The algorithm enjoys extensive and utilitarian application in mixed gas diving, both in recreational and technical sectors, and forms the bases for released tables, software, and decompression meters used by scientific, commercial, and research divers. The LANL Data Bank is described, and the methods used to deduce risk are detailed. Risk functions for dissolved gas and bubbles are summarized. Parameters that can be used to estimate profile risk are tallied. To fit data, a modified Levenberg-Marquardt routine is employed. The LANL Data Bank presently contains 2879 profiles with 20 cases of DCS across nitrox, trimix, and heliox deep and decompression diving. This work establishes needed correlation between global mixed gas diving, specific bubble model, and deep stop data. The objective is operational diving, not clinical science. The fit of bubble model to deep stop data is chi squared significant to 93%, using the logarithmic likelihood ratio of null set (actual set) to fit set. The RGBM model is thus validated within the LANL Data Bank. Extensive and safe utilization of the model as reflected in user statistics for tables, meters, and software also points to real world validation, that is, one without noted nor reported DCS spikes among RGBM divers. Collecting real world diving data is a global alternative to differential wet and dry testing, a very precise but limited statistical procedure. The approach here for technical, mixed gas, and serious decompression diving parallels the Project Dive Exploration (PDE) effort at DAN for recreational air and nitrox diving, but does not overlap quite obviously. The issue of deep stops versus shallow stops in diving is a hotly debated topic today, and this study reaffirms the efficacy of deep stops, especially as they link naturally to the LANL dual phase bubble model and data. The operational issue of deep stops and staging is one of timing, with questions of time and depth at all stops only addressed within consistent model and ranging data frameworks.

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Deep diving and short decompression by breathing mixed gases

Cited by 30 publications

References 0 publications

DECOMPRESSION FROM He-N2-O2 (TRIMIX) BOUNCE DIVES IS NOT MORE EFFICIENT THAN FROM He-O2 (HELIOX) BOUNCE DIVES

DECOMPRESSION FROM He-N2-O2 (TRIMIX) BOUNCE DIVES IS NOT MORE EFFICIENT THAN FROM He-O2 (HELIOX) BOUNCE DIVES

L’argon : utilisations, toxicité et stratégie analytique en toxicologie médicolégale

On Validation of a Popular Sport Diving Decompression Model

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