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On the calculation of the new oxygen exposure indices

Authors:
Miri Rosenblat at Tel Aviv University
Miri Rosenblat
Nurit Vered at Technion - Israel Institute of Technology
Nurit Vered
Albi Salm at SubMarineConsulting
Albi Salm
  • SubMarineConsulting
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Abstract

This communication is on the implementation of a tool to calculate the new oxygen exposure indices, i.e. the indices concerning the oxygen toxicity (-OT) for the central nervous system (CNS-) and the whole body, the pulmonary (P-)system, pls. cf. ref. [1] & [4] and all the references therein. It is not intendend to discuss the scientific background nor the physiological or statistical rationale of these new indices. As well it is not intended to give any guidelines, which one of these new indicators should be used. Instead, we only want to point out that there are already tools available for these tasks at hand, pls. cf. ref. [2]. That is, the tool relieves the inclined user (i.e.: diver, instructor, manager, LST, DMO, …) of the calculation needed for ESOT and Arieli K-values and / or of errors through look-up of the tabulated versions [3], p. 27 & 28, resp. the rounding errors, intrinsic to all tabulated values. Additional, the tool displays the standard, seasoned Ox-Tox indices from the NOAA / USN, i.e. the %CNS and the OTU oxygen exposure doses for easy & straightforward comparison with other tools and/or dive computers.
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1
On the calculation of the new
oxygen exposure indices
Miri Rosenblat, TAU
Nurit Vered, Technion Haifa
Albi Salm, SubMarineConsulting
(06.06.2023)
@ TEC 4.0: update! TLV / IL
DOI:
2
Abstract: slide # 3
Introduction: slide # 4
Methods: slide # 5
Results & Data: slides # 6 7
Discussion: slide # 8
References: slide 9
3
Abstract:
This short communication is only on the implementation of a
tool to calculate the new oxygen exposure indices, i.e. the
indices concerning the oxygen toxicity ( - OT) for the central nervous system
(CNS -) and the whole body, the pulmonary (P -)system, pls. cf. ref. [1] & [4]
and all the references therein.
It is not intendend to discuss the scientific background nor the physiological
or statistical rationale of these new indices. As well it is not intended to give
any guidelines, which one of these new indicators should be used. Instead,
we only want to point out that there are already tools available for these tasks
at hand, pls. cf. ref. [2].
That is, the tool relieves the inclined user (diver, instructor, manager, LST,
DMO, …) of the calculation needed for ESOT and Arieli K-values and / or
of errors through look-up of the tabulated versions [3], p. 27 & 28, resp. the
rounding errors, intrinsic to all tables.
Additional, the tool displays the standard, seasoned Ox-Tox indices
from the NOAA / USN, i.e. the %CNS and the OTU oxygen exposure doses
for easy & straightforward comparison with other tools and/or dive computers.
4
Introduction (1):
The validity resp. the rationale for the oxygen exposure
indices from USN / NOAA, i.e. the %CNS and the UPTD doses,
are debated since long as these are basically linear for multi-level exposures,
but the suggested underlying reaction kinetics of reactive oxygen species etc.
… is not. As well there are data available from operational hyper-oxic dives
(for eg . Arieli et al) which suggest other limits for oxygen-diving.
As per 2023, there are now alternatives. These are:
the K-value indices for CNS- & P-OT from Ran Arieli et al.
the ESOT for P-OT as a replacement for the UPTD
The physiologic rationale and the calculations are described in [1] & [3],
resp. in all the references of [1] and [4].
The handling of Ran Arielis K-values are described in [4], along with
operational examples and hints for the used tool.
5
Methods (1):
The calculation of ESOT / K-values are
described in-depth in [1] & [4] and all
the references therein.
The published formulas have been encoded
in FORTRAN and added as a new feature
to an already existing Version 3_11.
This is now, per 06.06.2023, in the BETA stage for testing:
https://www.divetable.info/beta/index_e.htm
The complete DIVE framework, including a handbook / manual and coefficient
matrixes for various seasoned perfusion models is downloadable for free:
https://www.divetable.info/DIVE_V3/V3e/index.htm
However, the latest features from 2023 will be adressed in the new version of
the handbook by Q4/2023.
6
Results & Data (1):
A SCUBA dive with
EAN / Nitrox32 to 40 m in fresh water,
for 20 min, the raw data:
7
Results & Data (2):
EAN32, 40 m, 20 min, fresh water, the compartment plot:
8
Discussion (1):
The expanded / updated Version 3_11 is now since 06.06.2023 in
a BETA test stage:
feature requests and bug-/ error-reports are welcome!
A word of caution concerning BETA versions of (any) software:
It is not the question, if there are errors or bugs in the software.
The real question is only, how & when these errors will show up!
9
References:
[1] Jan Risberg, Pieter-Jan van Ooij, Lyubisa Matity (6/2023)
From UPTD to ESOT: Monitoring hyperoxic exposure in surface-oriented
diving, DOI: 10.22462/01.01.2023.34, private communication: in print
[2] Rosenblat, M. Vered, N. (01.06.2022)
Synopsis & Fact Sheet: update per 06/2022 for
DIVE Version 3_11
DOI: 10.13140/RG.2.2.26855.11684
[3] Risberg, J. Møllerløkken, A. Eftedal, O.S. (11.02.2023)
Norwegian Diving- and Treatment Tables, 6th ed Rev. 0
[4] Vered, Nurit. Rosenblat, Miri. Salm, Albi. (2021). An agile
implementation of the "K-value": a severity index for CNS-and pulmonary
oxygen-toxicity.
DOI: 10.13140/RG.2.2.17583.87205
ResearchGate has not been able to resolve any citations for this publication.
From UPTD to ESOT: Monitoring hyperoxic exposure in surface-oriented diving
Article
Full-text available
  • Jan 2023
  • UNDERSEA HYPERBAR M
A recent review suggested that the measure K = t2 x pO24.57 (t is exposure time in h, pO2 in Atm) should replace UPTD as an exposure index for pulmonary oxygen toxicity (POT) in surface-oriented diving. K would better predict reduction in vital capacity (VC) during exposure and allow prediction of recovery. Although K is more accurate estimating VC changes than UPTD, the calculation of K is more extensive, particularly when estimating hyperoxic exposure for dives with multiple pO2 segments. Furthermore, and in contrast with UPTD, K is difficult to interpret on its own given its non-linear dimension of time. We suggest that a new metric: ESOT (Equivalent Surface Oxygen Time) should be used to replace UPTD. ESOT = t x pO22.285 (t is exposure time in min, pO2 in Atm). ESOT=1 is thus the hyperoxic exposure reached after 1 min breathing of 100% O2 at surface pressure. Hyperoxic monitoring by ESOT is more practical than K to apply in an operational environment, with no loss of accuracy in POT prediction. In addition, it intuitively allows interpreting hyperoxic exposures on its own, analogous to UPTD. The daily hyperoxic threshold limits suggested by Risberg and van Ooij for two, five and an unlimited number of successive diving days would translate to ESOTs of 650, 500 and 420 respectively.
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An agile implementation of the "K-value": a severity index for CNS-and pulmonary oxygen-toxicity
Presentation
Full-text available
  • Jun 2021
The K-value power functions for the central nervous system and pulmonary oxygen toxicity (CNS-OT, P-OT) are described in: [1], [2], [3], [4] & [5], pls. cf. chapter „References“. As Ran et al. would have it ([3], abstract), there is a need for an implementation. Which is what we did ([6], [7], [8], [9]). „Agile“ means here, in the context of IT-projects: a failure rate of 20 % is subliminally accepted … Which is why we put the software on the BETA TEST site of „DIVE“
View
) Norwegian Diving-and Treatment Tables
  • J Risberg
  • A Møllerløkken
  • O S Eftedal
Risberg, J. Møllerløkken, A. Eftedal, O.S. (11.02.2023) Norwegian Diving-and Treatment Tables, 6 th ed Rev. 0