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Abstract

Abstract: a somewhat belated case study for a sub-saturation dive on air to 8.5 m required for a GUINNESS® world-record of 36 h in-door underwater spinning in 2001 Methods: we analyzed the dive profile with the: USN Rev. 7 2018 tables [1], the DCIEM 1983 tables [2] and the shareware DIVE Version 3_11 from 11/2021 [3], [4]. Results: in one of the divers a mild case of DCS Type I in the left arm was assessed after dive #6 in the series of 9 dives. None of the used diving tables would give any hints of required decompression stops. Even when special rules for working & repetitive dives were taken into account, all the dives where considered as being within the „NDL“, the no-decompression-limits for the frame-works of the US Navy and the Canadian Navy.
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DCS Type I during a
sub-saturation dive on air to 8.5 m:
a case study
Miri Rosenblat, TAU
Nurit Vered, Technion Haifa
Yael Eisenstein & Albi Salm,
SubMarineConsulting
22.12.2021
DOI: t.b.d.!
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Abstract:
a somewhat belated case study for a
sub-saturation dive on air to 8.5 m required for the
GUINNESS® world-record of
36 h in-door underwater spinning 06.22. & 06.23.2001
Methods:
in hindsight we analyzed the dive profile with the
USN Rev. 7 2018 [1], the
DCIEM 1983 tables [2] and the shareware
DIVE Version 3_11 from 11/2021 [3], [4].
Results:
in one of the divers a mild case of DCS Type I in the left arm
was assessed after dive #6 in the series of 9 dives. None of the used
diving tables would give any hints of required decompression stops.
Even when special rules for working & repetitive dives were taken into
account, all the dives where considered as being within the „NDL“, the no-
decompression-limits for the frame-works of the US Navy and the
Canadian Navy.
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The dive pattern:
to be repeated 9 *
for 4 teams
to reach an overall bottom time of 9 * 4 = 36 h of
In-door Underwater Spinning (cycling on stationary
ergometers)
for the GUINNESS Book of World-Records® in 2001
D: 8.5 m
BT: 60 min
Stop SI: 180 min stop times
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The dive site: the indoor pool @ DICK-factory location
Team 4: Panagiotis,
Albi & Eric
(from left to right)
-------------- deco rig with
stage tanks
@ ca. 2.5 m
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The dive profile (Team 4, Friday, 06.22.2001, Day I):
Dive # time in:
# 1 @ 1500
# 2 @ 1900
# 3 @ 2300
Breathing gas: air
Water temperature: 25°C, 3 mm wetsuits
Bottom depth: 8.5 +/- 0.3 m, measured at mid-chest
Bottom time: 60 min (+ 5 min for team switch-over)
Safety Stop @ ca. 2.5 m for 3 - 5 min
Surface Intervall: ca. 3 hrs.
RMV / SAC: ca. 11 13 L/min.
D: 8.5 m
BT: 60 + 5 min
Stop SI: 180 min 5 min - stop times
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The dive profile (Team 4, Saturday, 06.23.2001, Day II):
Dive # time in:
# 4 @ 0300
# 5 @ 0700
# 6 @ 1100
# 7 @ 1500
# 8 @ 1900
# 9 @ 2300
Breathing gas: air
Water temperature: 25°C, 3 mm wetsuits
Bottom depth: 8.5 +/- 0.3 m, measured at mid-chest
Bottom time: 60 min (+ 5 min for team switch-over)
Safety Stops @ 2.5 m increasing from 5 to 20 min.
Surface Intervall: ca. 180 min. stop times
RMV / SAC: ca. 11 13 L/min.
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The dive profile (Albi, Sunday, 06.24.2001, Day III):
Dive
# 10 @ approx. 1500
Breathing gas: air
Water temperature:
Bottom depth: ca. 9.5 m
Bottom time: ca. 25 min
Recovery dive for the 3 bicycle-ergometers with lift-bags:
upon surfacing, the 3 ergometers collapsed mechanically
due to corrosion, expedited in the warm pool-water
with the chlorine chemicals / desinfectants .
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Discussion (1):
There were 4 teams each with 3 divers and approx.
10 stand-by divers. But due to frequent mishaps during
day II with various problems of equalizing, sinusitis,
bronchitis, and episodes of lipoid pneumonia due to a
compressor failure, only 7 divers completed
the series with 9 dives, one of them being the subject
with the DCS type I, that is: the co-author of this communication.
None of the consulted diving tables ([1], [2]) asked for decompression stops,
and, despite the conducted safety stops, there occured 4 cases of marginal
DCS and one DCS type I case.
Even when following the wisdom of theold master“ (pls. cf. „FACEPLATE“,
the official newsletter for divers and salvors of the USN)
by taking the next deepest entry in the tables for cold & strenuous dives
(which it was not), there has been still 17 min of residual NDL after dive #9.
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Discussion (2):
The DCIEM framework [2] is in the pro-world
still considered as more conservative than the
USN framework [1].
For avoiding a „table lock-in“ for repetitive dives
(pls. cf. the slides # 15 17 in the attachment for a „table lock-in“
in the USN paradigm), the DCIEM tables advises „upward adjusting one
letter“ if the RG of the repetitive dive matches the RG of the previous one ([2],
p. 1-25).
But nonetheless this did not alleviate the situation: dives #9 still being
considered as „NDL“-dives, pls. cf. slides # 18 & 19.
The diving tables for recreational diving either became as well quickly
locked-in“ (PADI RDP, AA. Bühlmann ZH-86) or the schedule exceeded
the table limits after the 3rd. (NAUI RGBM) or already after the 2nd. dive
(DECO 2000). And, as well, none of the used 20 different dive computers
indicated any decompression obligation!
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Discussion (3):
DIVE Version 3_11 ([3], [4] and all the references therein)
allows for adjusting many physiological parameters:
the oxygen consumption from 0.25 to 4 L/min
a Right-to-Left shunt during SI from 0 to 180 min.
a reduced perfusion during the nocturnal phases
or any empirical increase in compartment half-times due to other factors
or other asymmetric de-saturation processes
the respiratory quotient Rq
But when drawing on all of these parameters within
physiologic sound boundaries, not even the slightest
decompression obligation could be simulated.
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Discussion (4):
A modern, topical dive-computer like the SCUBAPRO /
UWATEC Galileo G2 with the latest firmware could indicate
a decompression obligation, but only in the most extreme
conservative setting of L7 or more of the proprietary
„Micro Bubble Level“ with Lx and x: 0 9, 0 i.e. L0
indicating an unmodified Bühlmann ZH-L 16 algorithm:
„TAT“ meaning „total ascent time“; more info on the various MB levels:
https://www.divetable.info/skripte/G2.pdf
https://www.divetable.info/skripte/G2_GF.pdf
MB
Level NDL @ 9 m
[min] TAT [min] for
BT 65 min stop time @
3 m [min]
L9 6 18 16
L8 7 11 9
L7 18 5 3
L6 138 -
L5 199 -
L0 199 -
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Discussion (5):
A screenshot from the dive planner with MB Level L9:
MB levels > 5 are increasingly unrealistic, since the allowed /
tolerated compartment N2-supersaturation drops below 30 %
of Bühlmanns ZH-L16 algorithm (ZH-86 table).
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Decompression Sickness, the DCS Type I case:
Assessed through 3 diving medicine professionals
from DCSI, the „Druckkammer-Centrum Stuttgart 1“
(HBO facility, now Ludwigsburg) who supervised all
diving activities during the 2 days.
At: Subject ALBI, ca. 1.5 h after surfacing from dive #6.
Then: Aspirin 500 mg, orally, before and after dive #7; and then:
Dive #7: i.e. wet recompression with EAN32, deco stop 10 min.
Dive #8: i.e. wet recompression with EAN36, deco stop 15 min.
Dive #9: i.e. wet recompression with EAN60, deco stop 20 min.
Fatigue & pain only symptoms (left ellbow, forearm, wrist, thumb)
persisted as well through Sunday (and the recovery dive), 2 * Aspirin
and the following three days (each 1 Aspirin, 500 mg).
Conclusion: no deterministic method could provide any reliable &
safe decompression schedule! DCS once again unveiled her stochastic
nature!
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Attachment:
Dive plans with USN tables @ 30 & 35 feet
Dive plans with DCIEM tables @ 9 & 12 m
Newspaper clipping from the local press
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Check with USN [1] for day I:
8.5 m fresh water 27.9 feet
next table entry 30 feet ( 9.15 m) in the optional „Shallow
Water Air Divesfor UW-ship husbandry etc.:
Dive #1
Table 2A-1 reads for 30 feet 76 min (instead of 62): RG F
Table 2A-2 with SI 2:38 (-3.31): RG C
RG C @ rept. Depth 30 feet: 39 min of RNT
Dive #2
60 + 5 + 39 = 104 min 107 min / RG H
RG H @ SI 2:38 (-3.29): RG E
RG E @ 30 feet: 63 RNT
Dive #3
60 + 5+ 63 = 128 min 145 min / RG J
RG J @ SI 2:38 (-3.29): RG G
RG G @ 30 feet: 92 RNT
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Check with USN [1] for day II:
Dive #4:
60 + 5 + 92 = 157 min 167 min / RG K
RG K @ SI 2:38: RG H
RG H @ 30 feet: 108 RNT
Dive #5
60 + 5 + 108 = 173 min 193 min / RG L
RG L @ SI 2:38 (-3.29): RG I
RG I @ 30 feet: 126 RNT
Dive #6
60 + 5 + 126 = 191 min 193 min / RG L
RG L @ SI 2:38: RG I
RG I @ 30 feet: 126 RNT
Dive #7, #8 & #9: the same, due totable lock-in“.
Since the NDL for 30 feet: 371 min,
the remaining NDL for dives #6 to #9 would be: 371 193 = 170 min.
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Check with USN [1] for day I & II („old master rule“):
next table entry 35 feet (instead of 30 feet)
BT / RG:
next RG after SI 2:38‘:
Dive #1: RNT:
60 + 5 = 65‘ 74‘ / G D 43
Dive #2:
65 + 43 = 108‘ 115‘ / J G 75
Dive #3:
65 + 75 = 140‘ 148‘ / L I 101
Dive #4:
65 + 101 = 166‘ 168‘ / M J 116
Dive #5:
65 + 116 = 181‘ 190 / N K 132
Dive #6:
65 + 132 = 197‘ 215‘ / O L 149
Dive #7:
65 + 149 = 214‘ 215‘ / O L 149 „table lock-in“
NDLs for dives # 8 & 9:
232 215 = 17 min
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Check with DCIEM [2] @ 9 m for day I & II:
19
Check with DCIEM [2] @ 12 m for day I & II:
20
From the
local
news-papers:
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References:
[1] U.S. Navy Diving Manual Revision 7,
Change A, 30 April 2018,
SS521-AG-PRO-010, 0910-LP-115-1921
[2] DCIEM Diving Manual (March 1992) DCIEM No. 86-R-53,
Defence and Civil Institute of Environmental Medicine, Ontario, Canada
[3] Rosenblat, Miri; Vered, Nurit (11/2021)
Synopsis & Fact Sheet for DIVE Version 3_11; DOI:
https://dx.doi.org/10.13140/RG.2.2.17024.56326
[4] Salm, Albi; Rosenblat, Miri; Vered, Nurit (07/2021)
A proof of concept for DIVE Version 3_10; DOI:
https://dx.doi.org/10.13140/RG.2.2.28123.69924
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