Scientific papers 1990 - 1995
This report explains experimentations made on 32 US
Navy divers immersed in a water at 3 celcius degrees for
periods up to 8 hours. Electrical resistance heated and
warm water perfused gloves were tried. However, hands
and feet remained dry by communication with the drysuit
Date of publication: September 1990
This report explains experimentations made in correction
of the US Navy saturation procedures published in 1978
that had triggered occasional vestibular decompression
sickness (DCS) cases after upward excursions from storage
depths between 800 and1000 feet of seawater.
Date of publication: June 1990
This document explains experimentations made on
animals to determine whether toxic events accumulated
over a relatively long oxygen exposure reversed on return
to normoxia at the same rates as those of shorter oxygen
exposures.
Date of publication: June 1991
This paper describes experimentations that demonstrated
that microbubbles impair the blood-brain barrier integrity
to protein, causing focal edema.
Year of publication: 1991
This paper describes COMEX procedures used in
November 1992 to reach 701 msw, which is still the
world record.
This successful experimental dive aimed to demonstrate
that the use of Hydreliox enhances the divers’
effectiveness and working capabilities and provides
improved safety and comfort for human intervention on
undersea oil production facilities.
This document discusses the detection and assessment of
venous gas emboli (bubbles) resulting from
decompression in divers. It highlights the use of ultrasonic
methods, particularly continuous-wave Doppler and
echocardiography, to detect these bubbles. It also
addresses the subjectivity and potential inaccuracies in
grading bubble signals, the need for better detection
methods in sport diving, and the authors' efforts to
evaluate and propose a methodology for using 2D
echocardiography and pulsed Doppler to quantify
circulating bubbles.
This paper, published in 1995, is another study that has
been used by other scientists later on. It thoroughly
investigates the various noise sources during diving
operations, including saturation, and provides accurate
measurements.
This document has been provided by Francis Hermans
This study verified the hypothesis that deep heliox diving
might influence postural control and the vestibular system.
Multiple postural controls were made in four divers
before, during, and after an onshore experimental heliox
saturation dive of 32 days. The depth was 450 msw.
Downward excursions to 470 msw were also performed.
Clinical Otolaryngology (also called ENT or Ear, Nose,
Throat) and otoneurological examinations, including
bithermal caloric vestibular testing with
electronystagmography (ENG), were performed.
The authors evaluated CO2 retention in 24 Navy
construction divers breathing air at 1 atm abs (101.3 kPa)
and 40% O2 (40/60) nitrox at 4 atm abs (PO2 of 162.1
kPa) inside a pressure chamber.
The "oxygen window" causes a partial pressure difference
of inert gas between the inside and outside
decompression bubbles. Estimates of PO2 and PCO2 in
tissue are necessary for O2 window calculations and any
calculations about the growth or decay of decompression
sickness bubbles, but the estimates involve many
uncertainties.
Using simplifying assumptions, the authors estimated the
O2 window range of environments for tissues having a
wide range of O2 extractions
In this study, published in 1991, the risk of decompression
sickness (DCS) during dives on various nitrogen/oxygen
breathing mixes is analyzed using likelihood maximazation
Authors: M. Jette, K. Sidney, G Blumchen
This article summarizes and presents energy expenditure
values in METS and watts units. Despite its limitations, the
MET concept provides a convenient method to describe
an individual's functional capacity or exercise tolerance as
determined by progressive exercise testing and to define a
repertoire of physical activities in which a person may
participate safely without exceeding a prescribed intensity
level.
This report contains a summary of all known results from
controlled human exposures to hyperbaric O2 at the time
of its publication in January 1993. The data were
collected to analyze and develop predictive models
relating to the risk of developing a symptom of central
nervous system O2 toxicity as a function of time, depth,
and exposure conditions.
This report, published in 1993, discussed the
decompression model ZH-L8 from professor Buhlman.
The decompression algorithm ZH-8 was based on eight
compartments, as suggested. It gave rise to sport diving
decompression tables known under the name "Buhlman
Tables", and massively used by many European sport
divers. Many pioneer manufacturers of diving computers
also used it. It has been followed by the ZH-12 and the
ZH-16, which many diving computer manufacturers still
use.
Authors: A L Harabin, S S Survanshi, L D Homer
This paper, published in March 1994, discussed of
analyzed central nervous system (CNS) oxygen toxicity
symptoms from 1726 controlled human hyperbaric
exposures at PO2 levels ranging from 0.3 to 2.9
atmospheres (atm) using risk models and maximum
likelihood analysis and tested specific hypotheses with
likelihood ratios. The data were sorted into dry, immersed,
no-exercise, and exercise conditions.
Author: Erik C. Baker
Robert D Workman (1885-1977) made a revision of
Haldane tables and found that the "tissue ratios" for
tolerated overpressure varied by half-time compartment
and by depth. The data showed that the faster half-time
compartments tolerated a greater overpressure ratio than
the slower compartments and that for all compartments,
the tolerated ratios became less with increasing depth.
Instead of using ratios, he described the maximum
tolerated partial pressure of nitrogen and helium for each
compartment at each depth as the "M-value". This concept
is still used by most modern decompression tables.
The salivary flow rate and composition of 2 groups of 31
subjects, one group at each extreme of the seasickness
susceptibility scale, were compared. No significant
differences were found between the two groups in flow
rates and electrolyte concentrations of whole resting and
stimulated saliva. Analyse activity and rate of secretion in
resting saliva were significantly higher in subjects
susceptible to seasickness as compared with non-
susceptible subjects. Also, the total protein rate of
secretion in resting saliva was significantly higher in the
susceptible group.
Forty-one percent of the dives were performed within the
decompression limits of the US Navy standard
decompression tables. Risk factors were fatigue,
circumstances suggesting dehydration, and extreme
physical effort. The most common presenting symptoms
were paresthesias, weakness of the legs, lower back pain,
or abdominal pain. Full recovery was achieved in 79% of
the patients.
Spinal symptoms appeared immediately on surfacing in six
of the eight patients who continued to have multiple
neurological sequelae.
Authors: judith Aharon-Peretz, YohaiAdir, Carlos R. Cordon,
Shahar Kol, Nachum Cal, Yefruda Melamed
Although pulmonary barotrauma (PBT) is a well-known
clinical entity, its recognition in divers is sometimes delayed
and its implications for future diving often are
unappreciated. The pulmonary complications of diving
activities range from mere discomfort from mediastinal
emphysema or pneumothorax, or both, to life-threatening
gas embolization. In nine cases described in this paper,
only minor manifestations were associated with PBT
which occurred at or close to the surface, but three of
these four divers were found to have abnormal
pulmonary function.
Author: K Todnem, H Nyland, H Skeidsvoll, R Svihus, P
Rinck, B K Kambestad, T Riise, J A Aarli.
The increased hyperbaric pressure influences the nervous
system during deep dives. The divers may experience
hand tremors, postural instability, gastrointestinal
problems, somnolence, and cognitive dysfunction. The
neurological symptoms and signs that may occur have
been termed high-pressure neurological syndrome
(HPNS). This syndrome has been known for more than
twenty years.
Authors: J How, A Vijayan, T M Wong
The Singapore Mass Rapid Transit (MRT) projectstarted
compressed air work in Oct 1984. Eleven km of
underground tunnels out of 20 km were built using this
method. Cases of decompression sickness (DCS)
arising from compressed air work are rare with working
pressures less than 1 bar gauge. However, there were 10
cases of DCS in the MRT project who were exposed to less
than 1 bar pressure. The authors present their clinical
features and attempt to explain the observations in
relation to theories of bubble nuclei formation, gas
loading and rate of decompression.
Publisher: American Academy of Underwater Sciences
Proceedings of a workshop held at Duke University
Medical Center in Durham, USA, in March 1991.
Publisher: American academy of underwater sciences
Proceedings of a workshop held in La Jola, California,
USA, in May 1991.
This workshop was sponsored by the National Science
Foundation, Polar Biology, and the American Academy of
Underwater Sciences.
Authors: R.B. Philp & D.J. Mclver
The authors studied the effects of elevated pressures of
inert and narcotic gases on calcium-dependent functions
and cytosolic calcium levels in human blood platelnts,
marine sponge cells and cultured human SK-N-SH
neuroblastoma cells using the intracellular calcium
indicator fura-2 AM. They found that many of the effects
of narcotic gases and of pressure (He) could be explained
by their influence on stimulated free cytosolic Ca2+ levels.
Authors: C. L. Shake, P. K. Weathersby, B. G. Coras, & arid
J. W. Parker
A disabled submarine (DISSUB) crew exposed to
increased atmospheric pressures resulting from flooding,
rupture of air lines, or emergency breathing apparatus use
may incur a decompression obligation and will require
gradual decompression to avoid decompression sickness
(DCS). Decompression in a nitrogen-oxygen mixture is not
always operationally feasible, and decompression from an
air exposure in helium and oxygen could result in isobaric
counter-diffusion DCS.
In this document, Bruce Wienke and Timothy O’Learly,
who are reputed authors on this subject explain their
comprehention on mixed gas diving.
Authors: F. M.N.H. Schramel, A.R.J. Van Keimpena, J. P.
Janssen, R. P. Golding, & P. E. Postmus
The aim of the present study was to analyse pulmonary
function parameters of patients with spontaneous
pneumothorax (SP) in relation to the extent of
emphysema-like changes (ELCs). Pulmonary function tests
were performed in 85 patients with unilateral SP, 6 weeks
after video-assisted thoracoscopy (VAT). In 63 patients,
thoracic computer tomography (CT) was obtained.
Author: O. Hyldegaard, M. Møller, J. Madsen
This paper relates to experiments in which air bubbles
were injected into the spinal white matter of rats and
studied at 1 bar after decompression from exposure to air
at 3.1 bar (absolute) for 4 hours to observe the effects of
heliox, pure oxygen, and nitrous oxide/oxygen breathing
on bubble reduction.
Authors: O. Hyldegaard, M. Møller, J. Madsen
Decompression sickness and spinal cord function for at
least three hours after decompression to I atm abs (101
kPa) following exposure to air at 3.8 atm abs (385 kPa) for
1 hour were studied using rats. Three groups of animals
were given either air, oxygen, or heliox (80/20) to breathe
at 1 atm abs for three hours after decompression. Both
oxygen and heliox breathing impeded the development
of DCS significantly. The effect of heliox seemed to be
superior to that of oxygen.
Authors: O. Hyldegaard, J. Madsen
This study aimed to examine the behavior of air bubbles in
three non-lipid tissues (skeletal muscle, tendon, and the
anterior chamber of the eye) during air, helium-oxygen
(heliox, 80:20), or oxygen breathing. Air bubbles were
injected into skeletal muscles or tendons in rats after
decompression from a l-h air exposure at 3.5 atm abs (355
kPa) or into the anterior chamber of the rat eye without
any previous pressure exposure. The bubbles were
studied by photomicroscopy at one atm abs (101 kPa)
during either air-breathing, or air-breathing followed by
heliox or O2 breathing..
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Authors: JP Imbert & S Montbarton
In 1974, Comex began using a computer system to
process its dive reports and to access this information
efficiently. The system was named the Comex Diving
Database and ran until the end of the company's diving
activities, with several revisions and updates. This database
enabled remarkable achievements, notably the
development of decompression procedures that are still in
use today. It can be seen as an example of a commercially
operated diving database.
Author: JP Imbert
In this presentation, Jean Pierre Imbert demonstrates that
by utilizing commercial diving databases, distinguishing
between the two types of decompression sickness, and
applying the arterial bubble model, it is evident that
surface decompression has a "natural" safe limit, closely
aligning with the guidelines set by the UK Department of
Energy Safety Memorandums. Exceeding this limit
generally results in a higher incidence of type 2
decompression sickness compared to continuous
decompression.
Authors: P. K. Weathersby, S. S. Survanshi, L.D. Homer, E.
Parker, and E. D. Thalmann
The researchers previously used probabilistic models and
maximum likelihood estimation to predict decompression
sickness (DCS). They improved their method by including
when DCS symptoms occur, which made their predictions
more accurate in a study of nearly 1,000 exposures. This
improvement helps to distinguish better between models
that can predict both the timing and occurrence of DCS
symptoms and those that only predict occurrences.
Authors: P.K. Weathersby, S.S. Survanshi, R.Y. Nishi,
E.D.Thalmann
Probabilistic models for decompression sickness (DCS)
require accurate data on diving profiles and DCS incidents
to effectively predict DCS risks. Over 400 experimental
dives from the U.S., U.K., and Canada since 1977 have
been compiled, checked, and prepared for these models.
This report outlines the data sources, review and
formatting process, and provides summaries of the data
collection.
Authors: Lawrence E. Armstrong, Carl M. Maresh, John W.
Castellani, Micheael F. Bergeron, Robert W.
Keriefick, Kent E. LaGasse, and Deborah Riebe
Urinary indices are used to assess the hydration status of
patients, determining whether they are well-hydrated,
euhydrated, or hypohydrated.
This document describes laboratory studies conducted to
determine if urine color accurately indicates hydration
status and to clarify the interchangeability of color, urine
osmolality, and urine specific gravity in research.
Publisher: The Undersea and Hyperbaric Medical Society
The facilitators and participants of this workshop, which
focused on evaluating the feasibility of diving for
individuals with asthma, engaged in a productive
discussion that highlighted key areas that need further
study. The panel ultimately distilled these discussions into
12 consensus statements, offering more precise and
flexible guidelines for determining the suitability of
individuals with asthma.
Authors:
Norihiro Miyamoto, Nobuo Matsui, Itaru Inque, Hisao Seo,
Kazuhiko Nakabayashi, and Hironori Oiwa
This study investigates the mechanism behind increased
urine flow (hyperbaric diuresis) in men exposed to a
hyperbaric environment. Five male subjects participated in
a dry saturation dive experiment, where they were
exposed to a helium-oxygen environment at 16-21 ATA
for four days. Blood and urine samples were collected at
various intervals. The results suggest that hyperbaric
diuresis is caused by both reduced antidiuretic hormone
and increased atrial natriuretic polypeptide secretion.
Authors:
Einar Thorsen, Kaire Segadal, Brit Kambestad, Amund
Gulsvik
This study measured pulmonary function in 152
professional saturation divers and a control group of 106
subjects. Various lung function parameters were assessed
and compared with reference values from Scandinavian
studies, British submariners, and the European Community
for Coal and Steel (ECCS). The findings suggest minor
airway dysfunction and transient lung function changes
after saturation dives, indicating cumulative long-term
effects of diving on pulmonary function.
Author: K Todnem, H Nyland, B K Kambestad, J A Aarli
This study investigated recorded neurological signs and
symptoms in 156 air and saturation divers compared to
100 controls. Divers exhibited significantly more general
neurological symptoms and abnormal findings than
controls, with prominent issues in concentration and
memory and signs of distal spinal cord or nerve root
dysfunction and polyneuropathy. These symptoms and
findings were significantly correlated with diving
exposure, DCS prevalence, and age.
Authors:
H.Y. Tao, H.J. Chen, H. Zhang, J. Guo, and F.K. Rong
lThis study investigated the effects of saturation-excursion
diving at pressures equivalent to 250 and 300 meters on
the urinary excretion of atrial natriuretic polypeptide
(ANP), antidiuretic hormone (ADH), and electrolytes in
four male divers. The divers were exposed to high-
pressure environments for two days, and urine samples
were collected day and night before, during, and after the
exposure. The study concluded that the increase in
nocturnal urine flow (nocturia) was primarily due to
stimulated ANP secretion.
Authors: R. Holden, C. D. G. Morsman, and C. M. Lane
The study conducted ocular fundus fluorescein
angiography on 26 divers with at least ten years of safe
diving practices and seven controls. The results showed
no significant difference in the incidence of macular
abnormalities between these groups and those from a
previous study. The findings suggest that adhering to safe
diving practices provides some protection against macular
abnormalities associated with decompression sickness in
divers.
A workshop was held at the USAF Armstrong Laboratory
in October 1990 to address altitude decompression
sickness (DCS), an operational limitation in aviation and
space activities. The event gathered over 50 participants
from the Department of Defense, NASA, and universities.
The workshop aimed to document the current
understanding of DCS and its operational significance,
especially as future military aircraft crews are expected to
encounter higher altitudes. The conclusions from this
document have to be linked to the transfer to altitude or
traveling by aircraft after diving
Authors:
Tim D. Oury, Ye-Shih Ho, Claude A. , and James D. Crapo
This paper investigates the role of extracellular superoxide
anion (O2-) in central nervous system (CNS) oxygen
toxicity using transgenic mice that overexpress human
extracellular superoxide dismutase (ECSOD) in the brain.
When exposed to hyperbaric oxygen, transgenic mice
showed higher mortality compared to nontransgenic
mice. The findings suggest that NO is a crucial mediator in
CNS oxygen toxicity and that ECSOD increases this toxicity
by inhibiting O2-mediated inactivation of NO.
Authors: E. Thorsen, K. Segadal, B.K. Kambestad
This study investigates the prolonged effects of deep
saturation diving on pulmonary function by measuring
various lung parameters before and after 17 different
diving operations to depths ranging from 5 to 450 meters
of seawater. The divers' pulmonary function was assessed
through static and dynamic lung volumes, transfer factor
for carbon monoxide (TLCO), and closing volume. The
conclusions are that hyperoxia, hyperbaric, and venous
gas micro embolism all contribute to changes in
pulmonary function after a single saturation dive,
potentially explaining some long-term effects on divers'
lung health.
Authors:
E.I Eger, J. Liu, D. D. Koblin, M.J. Laster, S. Taheri, M.J.
Halsey, P Ionescu, B.S. Chortkoff, and T. Hudlicky
The study examined 35 types of methanes, ethanes,
propanes, and butanes, including unfluorinated, partially
fluorinated, and perfluorinated variants, to identify
molecular properties that correlate with optimal anesthetic
solubility and potency. Additional data were collected on
longer-chained alkanes. The findings suggest that an ideal
anesthetic would have three or four carbon atoms with
single or dual hydrogenation of two carbons, particularly
terminal carbons.
Authors:
M.W.J. Cleeter, J.M. Coopefib, V.M. Darley-Usmard, S.
Moncadad, & A.H.V. Schapira
This study investigates the effect of S-nitrosoglutathione
(GSNO), a nitric oxide generator, on rat skeletal muscle
mitochondria. The findings suggest that nitric oxide can
rapidly and reversibly inhibit the mitochondrial respiratory
chain, potentially contributing to its cytotoxic effects in the
central nervous system (CNS) and other tissues.
Authors: Y.C. Lin, K. Shikaki, H Takeushi, and M. Mohri
This study investigates cardiovascular deconditioning (CD)
in subjects exposed to a hyperbaric environment of 31
ATA and subsequent decompression to sea level.
Measurements were taken before and after underwater
exercise, during early, mid, and late exposure to 31 ATA,
and post-dive. The conclusions are that hypovolemia is a
major factor in the acute phase of hyperbaric CD, and
prolonged inactivity may contribute to later phases.
Moderate daily exercise was not effective in preventing
hyperbaric CD.
