Scientific papers 2004 - 2006
The documents are classified chronologically from 2004 to 2006.
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Introduction:
Our decompression tradition is based on the principles set
by Haldane in 1908 (1). The classic or “Haldanian” models
used for the calculation of present tables all have the same
mathematical expression: a) they figure inert gas
exchanges with a series of exponential compartments; b)
they specify the safe ascent criteria as a linear relation
between the ambient pressure and the maximum
permitted compartment tension. As a consequence, these
models have produced similar decompression profiles,
characterized by a initial rapid ascent on a relatively high
distance. However, the drive for table development is
operational pressure. Aside the information circuits,
marginal divers’ communities have empirically developed
original decompression procedures for their needs.
Apparently, all share the same strategy and use slower
rates of ascent and deeper stops than would be predicted
by the Haldanian models.
An attempt is made to introduce new assumptions and
build them into a model to obtain the typical profile of
these successful decompressions.
UK HSE reseach report 244. Prepared by Unimed Scientific
Limited for the Health and Safety Executive 2004.
This document is a study of the decompression risks of
saturation diving with particular reference to the risks
which arise from depth changes during the work shifts,
excursions.
This study examined the relationship between thermal
conditions and DCS risk, the production of venous gas
embolism, or inert gas exchange. Also, the authors
conducted a second search for the effects of showering
on DCS and examined the Naval Medical Research
Institute (NMRI) DCS database for cases of DCS
associated with showering. Accepted epidemiological
criteria for the evaluation of causal relationships were
applied to the studies they found on the subject.
Optimization of oxygen tolerance extension by
intermittent exposure was studied in groups of 20 rats
exposed to systematically varied patterns of alternating
oxygen and normoxic breathing periods at 4.0, 2.0, and
1.5 ATA. Oxygen periods of 20, 60, and 120 min were
alternated with normoxic intervals that provided oxygen-
to-normoxia ratios of 4:1, 2:1, 1:1, and 1:3.
This paper gives a detailed history of the deep-diving
operations and researches undertaken by COMEX.
These operations and studies resulted in the creation of
tables such as those used by the French ministry of labour
and also the NORMAM 15/DPC procedures in Brazil.
Abstract:
Obesity has long been accepted as one of the many risk
factors for developing decompression sickness (DCS)
when diving. Whilst body fat is a great heat insulator,
there are a number of disadvantages to an obese person
diving. These disadvantages range from the physical
restriction of wetsuits to concurrent medical pathologies
and the higher demands on the cardiovascular and
pulmonary systems whilst swimming. The high solubility of
nitrogen in lipids and fats results in 5.4 times as much
storage of nitrogen in fat as muscle tissue. This increases
the supersaturation of fat with nitrogen and significantly
increases the risk of developing DCS. Whereas, historically,
dive medicals precluded obese people from diving, a
review of the literature would suggest that a sensible
approach to diving and the medical examination can
minimise risks of DCS to the obese patient.
Authors:
Zeljko Dujic, Darko Duplancic , Ivana Marinovic-Terzic,
Darija Bakovc, Vladimir Ivancev, Zoran Valic, Davor
Eterovic, Nadan M Petri, Ulrik Wisløff, and Alf O. Brubakk.
This study is a continuation of previous experiments that
demonstrated that a single bout of high-intensity aerobic
exercise 20 h before a simulated dive reduces bubble
formation and protects rats from decompression sickness.
The present study investigates the importance of these
findings in man.
Author: Sandro Longo
This paper reports experiments on the effects of air
bubbles on ultrasound velocity measurements in fluids.
The authors used an acoustic Doppler velocimeter system
to measure the three velocity components in a single
point and an acoustic Doppler velocimetry profiler system
to measure axial velocity in several points along the beam.
The results suggest that both systems essentially measure
the velocity of the bubbles, independent of the low air-
volume concentration and bubble radii in the flow field.
Editor: Daniel Mathieu
This Handbook is intended as a reference document for
researchers and clinicians alike to be used both in the
research laboratory and in everyday hyperbaric clinical
practice; it also provides support material for teachers.
The study's objective was to evaluate the
cardiopulmonary effects of open sea scuba air diving to
39 m (30 minutes bottom time) with standard
decompression. The variables were measured in different
post-dive body postures and compared with the baseline
values before the dive in the same posture to account for
possible gravity-dependent effects of venous gas bubbles.
Authors:
H. D. Van Liew & E. T. Flynn
The authors used a graphical approach to compare
prescriptions for ascent given by various air
decompression tables with outcomes of experimental
dives compiled in the U.S. Navy Decompression Database.
Authors:
Z. Dujic, I. Palada, A. Obad, D. Duplancic, D. Bakovic, & Z.
Valic.
Decompression sickness is initiated by the formation of
gas bubbles in tissue and blood if the divers return to
surface pressure too fast. The effect of exercise before,
during, and after dive on bubble formation is still
controversial. The team reported previously that strenuous
aerobic exercise 24 h before simulated dive ameliorates
venous bubble formation. The objective of this field study
was to evaluate whether mild, continuous exercise during
decompression has a similar impact.
Authors:
Jean-Eric Blatteau, Emmanuel Gempp, Franc¸ois-Michel
Galland, Jean-Michel Pontier, Jean-Marie Sainty, and
Claude Robinet.
A single bout of aerobic exercise 24 h before a dive
significantly reduces the formation of circulating venous
gas emboli (VGE) on decompression. The purpose of this
investigation was to determine the effect of aerobic
exercise 2 h before a dive.
Gas bubbles are the primary agent in producing the
pathogenic effects of decompression sickness. Bubble
formation during decompression is not simply the
consequence of inert gas supersaturation. Numerous
experiments indicate that bubbles originate as pre-existing
gas nuclei.
Sixteen U.S. Navy divers began a series of 4-hour dives at
a PO2
of 1.4 atm daily for two consecutive five-day weeks. Nine
divers were able to finish; all withdrawals were for
nonpulmonary reasons. Divers rested on the bottom of a
15-foot freshwater pool and breathe humidified 100%
oxygen open circuit from MK 20 full face masks. Flow-
volume curves and diffusing capacity were measured at
baseline, daily during diving, and after the series.
Symptoms and changes in pulmonary function values
were used to measure pulmonary oxygen toxicity, and
the results were compared to earlier series of similar four-
hour dives.
Authors:
A. Landolfi, Z.J. Yang, F. Savini, E.M. Camporesi, F. Faralli,
G. Bosco.
Bubble formation and platelet activation are major factors
contributing to decompression sickness. The authors
hypothesized that pretreatment with hyperbaric oxygen
immediately before a dive may reduce bubble formation
and platelet activation in humans.
Authors: David M. Dromsky, Bruce D. Spiess, Andreas
Fahlman.
The authors of this paper examined an adjunctive
treatment for severe decompression sickness (DCS) to be
used when hyperbaric treatment is delayed or
unavailable. It is based on the hypothesis that intravenous
perfluorocarbon (PFC) emulsion combined with 100%
inspired O2 would improve severe DCS outcomes.
Authors: A. O. Brubakk, D. Duplancic, Z. Valic, I. Palada,
A. Obad, D. Bakovic, U. Wisloff, and Z. Dujic.
During and after decompression from dives, gas bubbles
are regularly observed in the right ventricular outflow
tract. Several studies have documented that these bubbles
can lead to endothelial dysfunction in the pulmonary
artery, but no data exist on the effect of diving on arterial
endothelial function. The present study investigated if
diving or oxygen breathing would influence endothelial
arterial function in man.
Authors: Andreas Fahlman, David M. Dromsky.
Several physiological factors have been suspected of
affecting the risk of decompression sickness (DCS), but few
have been thoroughly studied during controlled
conditions. Dehydration is a potential factor that could
increase the risk of DCS. It has been suggested that
hydration may enhance inert gas removal or increase
surface tension of the blood.
Male Yorkshire swine were randomized into two groups
to verify that dehydration increases DCS risk. The hydrated
group received no medication and was allowed ad lib
access to water during a simulated saturation dive. The
dehydrated group received a diuretic medication without
access to water throughout the dive. Animals were then
compressed on air to 110 ft of seawater for 22 h and
brought directly to the surface at a rate of 30 fsw/ min.
Outcomes of death and non-fatal central nervous system
(CNS) or cardiopulmonary DCS were recorded.
Authors: Hugh Dainer, John Nelson, Kathryn Brass,
Elizabeth Montcalm-Smith, and Richard Mahon
When saturated, the direct ascent to the surface carries a
high risk of decompression sickness (DCS) and death, yet
may be necessary during rescue or escape. O2 has
demonstrated benefits in decreasing morbidity and
mortality resulting from DCS by enhancing inert gas
elimination. Perfluorocarbons (PFCs) also mitigate the
effects of DCS by decreasing bubble formation and
increasing O2 delivery. The authors hypothesized that
combining O2 prebreathing (OPB) and PFC
administration reduces DCS incidence and death
following saturation in an established 20-kg swine model.
Unimed Scientific Limited USL) has carried out a study of
yo-yo diving at the request of the UK Health and Safety
Executive. Yo-yo diving is defined as a series of dives with
short periods spent at depth alternating with similar
periods on the surface. In general, the total duration of
the series is within the time constraints for a single dive to
the same depth for the maximum time allowed without
incurring decompression stops.
.
Authors: T. Shimamiya, N. Terada, S. Yakabayashi, M.
Mohri
The authors investigated the immune changes in 4
subjects exposed to a 9-day simulated 30-m (400-kPa)
nitrogen-oxygen (nitrox) saturation dive and compared
the results with those of our previous study that showed
immune and mood changes in normobaric confinement.
Blood samples were taken before, during, and after the
dive or confinement and activated with an anti-CD2
agonistic antibody.
Authors: B.R. Wienke, Tim O’Leary
This document is not an actual study but a succession of
recommendations regarding the use of nitrox in
recreational diving.
Author: Page R Painter
The maximum metabolic rate (MMR) of mammals is
approximately proportional to M0.9, where M is the
mammal's body weight. Therefore, MMR increases with
body weight faster than the basal metabolic rate (BMR),
which is approximately proportional to M0.7. MMR is
strongly associated with the capacity of the cardiovascular
system to deliver blood to capillaries in the systemic
circulation, but the properties of this vascular system have
not produced an explanation for the scaling of MMR.
Authors: Zeljko Dujic, Ante Obad, Ivan Palada, Vladimir
Ivancev, and Zoran Valic.
The effect of post-dive exercise on bubble formation
remains controversial, although the current practice of
divers and aviators is to avoid strenuous exercise after
diving. The authors previously showed that exercising 24
h before a dive or during a decompression stop
significantly reduces bubble formation in man. The
objective of this study was to determine whether a short
period of strenuous post-dive exercise promotes venous
bubble formation.
Author: Michael Chappell
This work examinates pathogen bubble formation using a
bubble detection algorithm based on doppler
measurements. A mathematical model is then used to
describe the formation of bubbles in the body. Since the
precise form of vasculature nuclei is unknown, the effect
of nucleus geometry on bubble behaviour is explored.
The behaviour of a bubble that breaks away from the
nucleation site is also examined. Finally, the relationship
between bubbles forming in the blood and those forming
stationery in the tissue is modeled.
Authors: M. Marczak, & M. Pokorski
The authors investigated the ventilatory response to
normobaric poikilocapnic hyperoxia in healthy subjects.
The study was carried out in 26 subjects aged 26years,
who breathed pure oxygen through a two-way valve for
10 min. Ventilatory flow was recorded using a
pneumotachograph and minute ventilation was
calculated from the tidal and frequency components.
Authors:
Zeljko Dujic, Ivan Palada, Darko Duplancic, Ante Obad,
Ulrik Wisloff, Alf O Brubakk.
The authors say that a previous study showed that
exercise 20-24 h prior to a dive reduces bubble formation
and increases survival in rats exposed to a simulated dive.
Furthermore, they demonstrated that nitric oxide (NO)
might be involved in this protection; blocking the
production of NO increases bubble formation while
giving rats a long-lasting NO donor for 20 h and
immediately prior to a dive reduces bubble formation. This
study determined whether a short-lasting NO donor,
nitroglycerine, reduced bubble formation after standard
dives and decompression in man.
Authors:
Atih Ors, Guner Sonmez, Senol Yildiz, Gunalp Uzun,
Mehmet Guney Senol, Hakan Mutlu, Mehmet Saracoglu
This study was conducted with magnetic resonance
imaging (MRI) to evaluate attendants working inside
hyperbaric chambers (inside attendants) for hyperintense
brain lesions. Ten inside attendants and ten healthy
nondiving subjects were included in the study.
A questionnaire was used to obtain information about
subjects’ medical history, hyperbaric exposure history,
alcohol intake, and smoking habits. T1-weighted, T2-
weighted, and fluid-attenuated inversion recovery images
were acquired with a 1.5-T MRI device.
Authors:
A. Marroni , P. B. bennett, F. J. Cronje, R. Cali-Corleo, P.
Germompre , M. Pieri, C. Bonucelli, C. Balestra
This document describes experiments undertaken to verify
the hypothesis that a deep stop would significantly reduce
fast tissue bubble formation and neurological DCS risk. A
total of 181 dives were made to 82 fsw (25 m) by 22
volunteers. The conclusion was that a deep stop
significantly reduced Doppler-detected bubbles and tissue
gas tensions in the 5 and 10 min tissues, which has
implications for reducing the incidence of neurological
DCS in divers.
Author: N Bitterman
This document, published in 2015, briefly presents the
knowledge about CNS oxygen toxicity: the clinical
manifestations, descriptions, incidence of symptoms, and
the time duration relationship that defines the safety limits
and risk factors leading to enhanced toxicity to hyperbaric
oxygen. A general outline presents suggested
mechanisms underlying hyperoxia-induced seizures and
strategies for protection against the attacks.
Author: Barbara Shykoff
This document describes experimental four-hour resting
dives while breathing 100% O2 underwater at a partial
pressure of 1.35 atm performed by the US Navy. Its
conclusion is that although even single four-hour dives at
PO2 = 1.35 atm entail some risk of pulmonary injury,
repeated dives with surface intervals of 20 hours for up to
five days do not appear to be more damaging.
Author: R. Kłos
Research on the validation of decompression tables is one
of the common subject areas of the cooperation
undertaken between the DRDC Toronto, Canada, and
The Naval University of Gdynia, Poland.
A survey of diving technologies has been conducted for
Scientific Research and the Polish Navy. Among the most
critical problems discussed have been various aspects of
decompression safety. The following is a study to
standardize and unify validation procedures for
decompression in the Polish Navy.
Authors: I Grover, W Reed, & T Neuman
A three-point scale, the SANDHOG (SAN Diego Diving
and Hyperbaric Organizations) criteria, was developed to
diagnose DCS (decompression sickness), and validated
against a known database of diving related injuries.
Authors: Ran Arieli, Yehuda Arieli, Yochanan Daskalovic,
Mirit Eynan, and Amir Abramovich
The aims of this study were to report the sensations and
symptoms that accompany CNS oxygen toxicity accidents,
and to evaluate whether loss of consciousness can occur
without any warning signs.
Authors: (R.D Vann, W.A Gerth, P.J Denoble, C.F Pieper, &
E.D Thalmann
The authors conducted experimental trials of flying after
diving using profiles near the no-decompression
exposure limits for recreational diving. The objective was
to determine the dependence of DCS occurrence during
or after flight on the length of the pre-flight surface
intervals (PFSI).
Author: Jan Risberg
This small text comments on the manuscript of McInnes
et al. reporting DCS incidence in guinea pigs exposed to
“forward” and “reverse.” Multi-level dive profiles.
The Brooklyn bridge design was made by John Augustus
Roebling, an architect with a relatively modest experience
in suspended bridge construction. He died few days after
the beginning of the construction work, after stepping on
a cable round and contacting tetanus.
His son, Washington Augustus Roebling, took over the
project management. Unfortunately, as a fire started in the
deepest caisson wooden structure, he spent more than
12 hours at 30 m in the caisson trying to fight the fire and
decompressed without any stop. As he became crippled,
he was forced to stay at his office. He kept controlling the
work with his binoculars while his wife Emily helped him
communicating with the workers. When the bridge was
inaugurated in 1883, Phineas Barnum demonstrated his
strength by crossing the river with the 21 elephants of his
circus.
Very large caissons were employed in the construction of
the Brooklyn Bridge, one of them being sunk to a
maximum depth of 30 m. The working conditions were
dramatic and there were at least 27 fatalities. There was
neither knowledge nor understanding of the
decompression process. Although 110 cases of serious
decompression illness were recorded by the attending
physician, recompression was not used for treatment. It
was on the Brooklyn Bridge project that the word “bends”
was coined for decompression illness. A stilted way of
walking affected by fashionable ladies of the time was
termed “the Grecian Bend”. When the caisson workers
showed signs of decompression illness, their painful
attitude suggested the Grecian Bend. The term was
shortened to “doing the bend” and finally “bends” or
“bent” became legitimized by use.
Authors:
K. Kohshi, R. M. Wong, H. Abe, T. Katoh, T. Okudera, Y,
Mano
Four professional Japanese breath hold divers (Ama) with
histories of diving accidents were reported.
Magnetic resonance imaging of these divers detected
cerebral infarcts localized in the watershed areas of the
brain. A survey conducted on their island revealed that
many Ama divers had experienced stroke-like events. A
clinical feature of DCI in breath hold diving is that the
damage is limited to the brain. Although the mechanisms
of brain damage in BH diving are unclear, N2 bubbles
passing through the lungs or the heart so as to become
arterialized are most likely to be the etiological factor.
Author: John B. West
In 1660, Robert Boyle (1627–1691) published his
landmark book New Experiments Physico-Mechanicall,
Touching the Spring of the Air, and its Effects in which he
described the first controlled experiments of the effects of
reducing the pressure of the air. Critical to this work was
the development of an air pump by Boyle with Robert
Hooke (1635–1703). For the first time, it was possible to
observe physical and physiological processes at both
normal and reduced barometric pressures.
Authors:
Richard A. Neubauer, Virginia Neubauer, & Franz
Gerstenbrand
Controlled studies have demonstrated safety and efficacy
of hyperbaric oxygenation therapy (HBOT) in the
treatment of anoxic, traumatic, ischemic, or thrombotic
brain injury.
Clinical improvements were correlated with increased
perfusion and metabolism, with reactivation of idling
neurons demonstrated by sequential single photon
emission computerized tomographic (SPECT) scanning.
Authors: T. Stensrud, S. Berntsen, K.-H. Carlsen
Exercise-induced bronchoconstriction (EIB) increases in
cold and dry air and decreases in humid air in subjects
with asthma. Few reports have reported on the effect of
humid environment upon exercise capacity in subjects
with EIB.
The primary aim of the present study was to examine the
effect of changing the humidity of the environmental air
upon exercise capacity measured by peak oxygen uptake,
peak ventilation and peak running speed and secondarily
to assess the influence of environmental humidity upon
EIB in subjects suffering from EIB.
Publisher: Smithsonian Institution, Washington, DC
The scope of this workshop, held in february 2006, was to
address the following topics:
Review of past efforts to expand scientific diving
capabilities
Comparison of advantages/disadvantages of advanced
diving techniques and equipment, including but not
limited to safety, training, limitations, cost, and support
requirements:
Evaluation of existing commercial diving and military
procedures’ applicability as an advanced scientific diving
tool;
Review advances in decompression protocols that
optimize the dive profile decompression obligations; and
Through user group input assess advanced scientific
diving needs for ecosystem management objectives;
