Reduced gradient bubble model

Wienke, B. R.

doi:10.1016/0020-7101(90)90048-y

Cited by 36 publications

(23 citation statements)

References 11 publications

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“…Studies of bubbles detectable with methods such as ultrasound demonstrate that the presence of bubbles is not sufficient to generate DCS, and venous gas emboli can pose little risk in some subjects. A scoring system for the volume and number of macroscopic bubbles has been developed, and higher scores apparently indicate higher risk for developing DCS (Wienke 1989b(Wienke , 1990Neuman 2003;Nishi et al 2003). However, it is difficult to relate this kind of scoring to the predictions of bubble size generated by our model.…”

Section: Bubblesmentioning

confidence: 99%

Repetitive Shallow Dives Pose Decompression Risk in Deep‐diving Beaked Whales

Zimmer¹,

Tyack

2007

Marine Mammal Science

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The impact of naval sonar on beaked whales is of increasing concern. In recent years the presence of gas and fat embolism consistent with decompression sickness (DCS) has been reported through postmortem analyses on beaked whales that stranded in connection with naval sonar exercises. In the present study, we use basic principles of diving physiology to model nitrogen tension and bubble growth in several tissue compartments during normal diving behavior and for several hypothetical dive profiles to assess the risk of DCS. Assuming that normal diving does not cause nitrogen tensions in excess of those shown to be safe for odontocetes, the modeling indicates that repetitive shallow dives, perhaps as a consequence of an extended avoidance reaction to sonar sound, can indeed pose a risk for DCS and that this risk should increase with the duration of the response. If the model is correct, then limiting the duration of sonar exposure to minimize the duration of any avoidance reaction therefore has the potential to reduce the risk of DCS.

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Section: Bubblesmentioning

confidence: 99%

Repetitive Shallow Dives Pose Decompression Risk in Deep‐diving Beaked Whales

Zimmer¹,

Tyack

2007

Marine Mammal Science

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“…Next, the analysis is extended to profiles with varying ascent and descent rates, safety stops, and repetitive sequence [53,[78][79][80]82]. Table 7 lists nominal profiles (recreational) for various depths, exposure and travel times, and safety stops at 5 msw.…”

Section: Nonstop and Repetitive Air Divingmentioning

confidence: 99%

“…These follow from a closer look at dissolved and bubble gas phases across the profiles, using LANL tools and selected way points on the dives. These comments also apply to deep and decompression staging using traditional dissolved gas models and tables [13,78,89]. Remember these comments are made within the LANL model framework and attendant data correlation:…”

Section: Gas Transport Analysismentioning

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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“…50,82,83 Hills' theory of "zero supersaturation" provided an explanation for the beneficial effect of deep stops: supersaturation caused immediate bubble formation, which could be avoided by deep decompression stops. 81 Controlling the formation and growth of bubbles has been the rationale of modern decompression models 72,73,[84][85][86] that tend to have deeper decompression stops than the U.S. Navy tables. After helium-oxygen diving, Momsen 53 and Cabarrou 87 reported that unexpectedly deep decompression stops were required to limit DCS risk.…”

Section: Return Of the Deep Stopmentioning

confidence: 99%

Inert Gas Exchange and Bubbles

Vann¹

2004

Bove and Davis' Diving Medicine

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Reduced gradient bubble model

Cited by 36 publications

References 11 publications

Repetitive Shallow Dives Pose Decompression Risk in Deep‐diving Beaked Whales

Repetitive Shallow Dives Pose Decompression Risk in Deep‐diving Beaked Whales

On Validation of a Popular Sport Diving Decompression Model

Inert Gas Exchange and Bubbles

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