Oxygen Breathing Accelerates Decompression from Saturation at 40 msw in 70-kg Swine

Petersen, Kyle; Soutière, Shawn E.; Tucker, Kathryn E; Dainer, Hugh M.; Mahon, Richard T.

doi:10.3357/asem.2681.2010

Cited by 6 publications

(6 citation statements)

References 2 publications

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“…Cardiopulmonary DCS was defined as sustained (Ͼ1 min) clinical evidence of severely compromised oxygenation and hemodynamic instability, specifically any of the following: hemoglobin saturation of Ͻ80%, mean HR of Ͼ150% of baseline, and mean respiratory rate of Ͼ200% baseline. Cutis marmorata was defined as onset of a typical violaceous mottled or marbled skin pattern, as defined previously (21,26). We used data segments for analysis following diagnosis of cutis marmorata (cutis) and cardiopulmonary (CP) DCS as determined by a trained observer.…”

Section: Experiments Protocolmentioning

confidence: 99%

The autonomic effects of cardiopulmonary decompression sickness in swine using principal dynamic mode analysis

Yan

Selvaraj

Petersen

et al. 2013

American Journal of Physiology-Regulatory, Integrative and Comp

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Methods to predict onset of cardiopulmonary (CP) decompression sickness (DCS) would be of great benefit to clinicians caring for stricken divers. Principal dynamic mode (PDM) analysis of the electrocardiogram has been shown to provide accurate separation of the sympathetic and parasympathetic tone dynamics. Nine swine (Sus scrofa) underwent a 15-h saturation dive at 184 kPa (60 ft. of saltwater) in a hyperbaric chamber followed by dropout decompression, whereas six swine, used as a control, underwent a 15-h saturation dive at 15 kPa (5 ft. of saltwater). Noninvasive electrocardiograms were recorded throughout the experiment and autonomic nervous system dynamics were evaluated by heart rate series analysis using power spectral density (PSD) and PDM methods. We observed a significant increase in the sympathetic and parasympathetic tones using the PDM method on average 20 min before DCS onset following a sudden induction of decompression. Parasympathetic activities remained elevated, but the sympathetic modulation was significantly reduced at onset of cutis and CP DCS signs, as reported by a trained observer. Similar nonsignificant observations occurred during PSD analysis. PDM observations contrast with previous work showing that neurological DCS resulted in a >50% reduction in both sympathetic and parasympathetic tone. Therefore, tracking dynamics of the parasympathetic tones via the PDM method may allow discrimination between CP DCS and neurological DCS, and this significant increase in parasympathetic tone has potential use as a marker for early diagnosis of CP DCS.

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Section: Experiments Protocolmentioning

confidence: 99%

The autonomic effects of cardiopulmonary decompression sickness in swine using principal dynamic mode analysis

Yan

Selvaraj

Petersen

et al. 2013

American Journal of Physiology-Regulatory, Integrative and Comp

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“…Such knowledge could be of great value also for practical use of the model for planning of saturation decompressions in case of emergency, when high partial pressure of oxygen is empirically used for accelerating desaturation. Some modeling research has already been done [ 55 ], some studies on animals have been conducted [ 56 ], several procedures have been recommended [ 57 , 58 ], and recently, this method has been investigated in humans [ 11 , 59 ]. Even if “the advantages of oxygen appear far less than predicted by current decompression models” [ 60 ], using a high amount of oxygen for accelerating decompression is already recommended in case of emergency [ 55 , 61 ].…”

Section: Resultsmentioning

confidence: 99%

The Extended Oxygen Window Concept for Programming Saturation Decompressions Using Air and Nitrox

2015

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Saturation decompression is a physiological process of transition from one steady state, full saturation with inert gas at pressure, to another one: standard conditions at surface. It is defined by the borderline condition for time spent at a particular depth (pressure) and inert gas in the breathing mixture (nitrogen, helium). It is a delicate and long lasting process during which single milliliters of inert gas are eliminated every minute, and any disturbance can lead to the creation of gas bubbles leading to decompression sickness (DCS). Most operational procedures rely on experimentally found parameters describing a continuous slow decompression rate. In Poland, the system for programming of continuous decompression after saturation with compressed air and nitrox has been developed as based on the concept of the Extended Oxygen Window (EOW). EOW mainly depends on the physiology of the metabolic oxygen window—also called inherent unsaturation or partial pressure vacancy—but also on metabolism of carbon dioxide, the existence of water vapor, as well as tissue tension. Initially, ambient pressure can be reduced at a higher rate allowing the elimination of inert gas from faster compartments using the EOW concept, and maximum outflow of nitrogen. Then, keeping a driving force for long decompression not exceeding the EOW allows optimal elimination of nitrogen from the limiting compartment with half-time of 360 min. The model has been theoretically verified through its application for estimation of risk of decompression sickness in published systems of air and nitrox saturation decompressions, where DCS cases were observed. Clear dose-reaction relation exists, and this confirms that any supersaturation over the EOW creates a risk for DCS. Using the concept of the EOW, 76 man-decompressions were conducted after air and nitrox saturations in depth range between 18 and 45 meters with no single case of DCS. In summary, the EOW concept describes physiology of decompression after saturation with nitrogen-based breathing mixtures.

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“…Pigs ( Sus scrofa , 17–23 kg, Table 3 ): The data set contained 125 previously published, well-documented hyperbaric exposures from juvenile male Yorkshire pigs 37 , an additional 41 hyperbaric exposures 38 39 of male Yorkshire pigs (same vendor) of larger size (59–79 kg) were also included. The hyperbaric experiments of the larger pigs were performed in a similar chamber, and scored by the same research group as for the smaller pigs.…”

Section: Methodsmentioning

confidence: 99%

“…To accommodate the different experimental designs, “T2” was defined as the end of the observation period. Upon returning to 1 ATA the observation times ranged from 5 min for mice 5 to 120 min for large pigs 38 39 .…”

Section: Methodsmentioning

confidence: 99%

Allometric scaling of decompression sickness risk in terrestrial mammals; cardiac output explains risk of decompression sickness

Fahlman¹

2017

Sci Rep

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A probabilistic model was used to predict decompression sickness (DCS) outcome in pig (70 and 20 kg), hamster (100 g), rat (220 g) and mouse (20 g) following air saturation dives. The data set included 179 pig, 200 hamster, 360 rat, and 224 mouse exposures to saturation pressures ranging from 1.9–15.2 ATA and with varying decompression rates (0.9–156 ATA • min−1). Single exponential kinetics described the tissue partial pressures (Ptiss) of N2: Ptiss = ∫(Pamb – Ptiss) • τ−1 dt, where Pamb is ambient N2 pressure and τ is a time constant. The probability of DCS [P(DCS)] was predicted from the risk function: P(DCS) = 1−e−r, where r = ∫(PtissN2 − Thr − Pamb) • Pamb–1 dt, and Thr is a threshold parameter. An equation that scaled τ with body mass included a constant (c) and an allometric scaling parameter (n), and the best model included n, Thr, and two c. The final model provided accurate predictions for 58 out of 61 dive profiles for pig, hamster, rat, and mouse. Thus, body mass helped improve the prediction of DCS risk in four mammalian species over a body mass range covering 3 orders of magnitude.

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Oxygen Breathing Accelerates Decompression from Saturation at 40 msw in 70-kg Swine

Abstract: Profile 1 performed best, shortening decompression with no death or severe DCS, yet it may still exceed emergency operational utility in an actual submarine rescue.

Cited by 6 publications

References 2 publications

The autonomic effects of cardiopulmonary decompression sickness in swine using principal dynamic mode analysis

The autonomic effects of cardiopulmonary decompression sickness in swine using principal dynamic mode analysis

The Extended Oxygen Window Concept for Programming Saturation Decompressions Using Air and Nitrox

Allometric scaling of decompression sickness risk in terrestrial mammals; cardiac output explains risk of decompression sickness

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