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Marginal DCS events: their relation to decompression and use in DCS models.

Publication ,  Journal Article
Howle, LE; Weber, PW; Vann, RD; Campbell, MC
Published in: Journal of applied physiology (Bethesda, Md. : 1985)
November 2009

We consider the nature and utility of marginal decompression sickness (DCS) events in fitting probabilistic decompression models to experimental dive trial data. Previous works have assigned various fractional weights to marginal DCS events, so that they contributed to probabilistic model parameter optimization, but less so than did full DCS events. Inclusion of fractional weight for marginal DCS events resulted in more conservative model predictions. We explore whether marginal DCS events are correlated with exposure to decompression or are randomly occurring events. Three null models are developed and compared with a known decompression model that is tuned on dive trial data containing only marginal DCS and non-DCS events. We further investigate the technique by which marginal DCS events were previously included in parameter optimization, explore the effects of fractional weighting of marginal DCS events on model optimization, and explore the rigor of combining data containing full and marginal DCS events for probabilistic DCS model optimization. We find that although marginal DCS events are related to exposure to decompression, empirical dive data containing marginal and full DCS events cannot be combined under a single DCS model. Furthermore, we find analytically that the optimal weight for a marginal DCS event is 0. Thus marginal DCS should be counted as no-DCS events when probabilistic DCS models are optimized with binomial likelihood functions. Specifically, our study finds that inclusion of marginal DCS events in model optimization to make the dive profiles more conservative is counterproductive and worsens the model's fit to the full DCS data.

Duke Scholars

Published In

Journal of applied physiology (Bethesda, Md. : 1985)

DOI

EISSN

1522-1601

ISSN

8750-7587

Publication Date

November 2009

Volume

107

Issue

5

Start / End Page

1539 / 1547

Related Subject Headings

  • Risk Factors
  • Risk Assessment
  • Proportional Hazards Models
  • Physiology
  • Models, Biological
  • Incidence
  • Humans
  • Decompression Sickness
  • Computer Simulation
  • 42 Health sciences
 

Citation

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Howle, L. E., Weber, P. W., Vann, R. D., & Campbell, M. C. (2009). Marginal DCS events: their relation to decompression and use in DCS models. Journal of Applied Physiology (Bethesda, Md. : 1985), 107(5), 1539–1547. https://doi.org/10.1152/japplphysiol.00185.2009
Howle, Laurens E., Paul W. Weber, Richard D. Vann, and Mark C. Campbell. “Marginal DCS events: their relation to decompression and use in DCS models.Journal of Applied Physiology (Bethesda, Md. : 1985) 107, no. 5 (November 2009): 1539–47. https://doi.org/10.1152/japplphysiol.00185.2009.
Howle LE, Weber PW, Vann RD, Campbell MC. Marginal DCS events: their relation to decompression and use in DCS models. Journal of applied physiology (Bethesda, Md : 1985). 2009 Nov;107(5):1539–47.
Howle, Laurens E., et al. “Marginal DCS events: their relation to decompression and use in DCS models.Journal of Applied Physiology (Bethesda, Md. : 1985), vol. 107, no. 5, Nov. 2009, pp. 1539–47. Epmc, doi:10.1152/japplphysiol.00185.2009.
Howle LE, Weber PW, Vann RD, Campbell MC. Marginal DCS events: their relation to decompression and use in DCS models. Journal of applied physiology (Bethesda, Md : 1985). 2009 Nov;107(5):1539–1547.

Published In

Journal of applied physiology (Bethesda, Md. : 1985)

DOI

EISSN

1522-1601

ISSN

8750-7587

Publication Date

November 2009

Volume

107

Issue

5

Start / End Page

1539 / 1547

Related Subject Headings

  • Risk Factors
  • Risk Assessment
  • Proportional Hazards Models
  • Physiology
  • Models, Biological
  • Incidence
  • Humans
  • Decompression Sickness
  • Computer Simulation
  • 42 Health sciences