Scientific papers 2006
Author: Gisele ML Mouret
Obesity is a known risk factor for decompression sickness
(DCS) in diving due to factors like increased nitrogen
storage in fat, physical restrictions, and higher demands
on cardiovascular and pulmonary systems. Although
traditionally obese individuals were often barred from
diving, current evidence suggests that with careful
medical assessment and precautions, diving can be made
safer for obese divers.
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.
Authors: J.E. Blatteau, J. B. Souraud, E. Gempp,
A. Boussuges.
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.
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: Andreas Fahlman, David M. Dromsky.
Several physiological factors might influence the risk of
decompression sickness (DCS), with dehydration being a
notable potential contributor. To investigate this, a study
involving male Yorkshire swine was conducted, with
animals divided into hydrated and dehydrated groups.
The hydrated group had ad lib access to water, while the
dehydrated group was administered a diuretic without
water during a simulated saturation dive. Following a 22-
hour compression to 110 ft of seawater, outcomes related
to death and non-fatal 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.
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.
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:
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: 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.
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.
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;
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Author: Zhongjie Sun
This study examines the role of vasopressin (AVP) in cold-
induced hypertension and diuresis using Long-Evans (LE)
and AVP-deficient Brattleboro (VD) rats. The findings
indicate that AVP does not contribute to cold-induced
hypertension but is essential for cold-induced diuresis. This
diuresis results from the suppression of renal V2 receptors
and AQP-2 water channels, rather than the inhibition of
AVP release.
Authors: Andreas Fahlman and David M. Dromsky
This study examines how dehydration affects the risk of
decompression sickness (DCS) in male Yorkshire swine.
Two groups were created: one with free access to water
(hydrated) and another given a diuretic (Lasix) with no
water access (dehydrated). Both groups experienced a
simulated dive to 110 feet of seawater for 22 hours,
followed by a rapid ascent. The findings show that
hydration status during decompression significantly
impacts the incidence and onset of DCS.
Authors: I.T. Demchenko, C.A. Piantadosi
The study examines whether central nervous system
(CNS) oxygen toxicity, which causes generalized motor
convulsions, is due to an imbalance between excitatory
and inhibitory neurotransmitters caused by neuronal nitric
oxide (NO) activity. Anesthetized rats were exposed to
high-pressure oxygen (HBO2) at 5 ATA for 75 minutes,
with some receiving an nNOS inhibitor (7-NI) beforehand.
The study concludes that HBO2-stimulated neuronal NO
production disrupts the balance between glutamatergic
and GABAergic synaptic functions, contributing to
oxygen-induced seizures.
Authors:
Bernadette P. Cabigas, Jidong Su, William Hutchins, Yang
Shi, Richard B. Schaefer, René F. Recinos, Vani Nilakantan,
Eric Kindwall, Jeffrey A. Niezgoda, John E. Baker
This study investigates the roles of the fraction of inspired
oxygen (FIO2) and atmospheric pressure (ATM) in
cardioprotection. Researchers treated adult Sprague
Dawley rats with different oxygen levels and atmospheric
pressure combinations to determine their effects on heart
protection. The study concludes that cardioprotection
from hyperoxia+hyperbaria depends on oxygen
availability and is mediated by NOS.
Authors: Igor B. Mekjavic & Ola Eiken
The text examines the concept of a set point in body
temperature regulation, which traditionally implies that
deviations from this set point trigger heat production and
heat loss responses. However, experiments show that
sweating and shivering responses do not converge on a
single set point but form a thermoeffector threshold zone.
The review suggests that non-thermal factors significantly
influence temperature regulation, often acting beyond
mutual inhibition.
Author: A. Møllerløkken, V. J. Berge, A. Jørgensen, U.
Wisløff, and A. O. Brubakk)
This study investigates the effect of a short-acting nitric
oxide (NO) donor on vascular bubble formation during
and after decompression from a saturation dive in pigs.
Fourteen pigs were divided into an experimental group
receiving intravenously NO donor and a control group.
The pigs were subjected to a hyperbaric environment and
then decompressed. The results showed a significant
reduction in the average number of bubbles in the
experimental group compared to the control group,
supporting the role of NO in preventing vascular bubble
formation after decompression.
Authors: H.B. Newton, W. Padilla, J. Burkart, D. K. Pearl
The study examines neurological symptoms in 200
recreational divers with decompression illness (DCI). The
divers, mostly male with a median age of 40 and 100 prior
dives, experienced rapid ascent in 22% of cases.
Neurological symptoms appeared within 60 minutes of
surfacing, with 88.5% showing at least one symptom.
Common symptoms included paresthesia, dysesthesia,
incoordination, motor weakness, and dizziness. Younger
and less experienced divers had more paresthesias, while
female divers experienced more painful skin symptoms.
Authors:
Ante Obad, Ivan Palada Zoran Valic, Vladimir Ivancev,
Darija Bakovic, Ulrik Wisløff , Alf O. Brubakk, and Zeljko
Dujic
This study investigated the effects of acute antioxidants
(vitamins C and E) on cardiovascular changes before and
after diving. Seven experienced divers participated in
open-water dives to 30 msw with standard
decompression. The study used both non-randomized
and randomized placebo-controlled crossover designs. It
concludes that acute antioxidants can attenuate arterial
endothelial dysfunction after diving but do not affect
cardiac and pulmonary artery function. Cardiovascular
changes induced by diving may persist for up to three
days, suggesting longer-lasting adverse effects.
Authors: A.E. Talpalar & Y. Grossman
This study intends to provide a scientific explanation and
analysis of the effects of high pressure on neurological
function, explicitly focusing on the high-pressure
neurological syndrome (HPNS) observed in humans and
animals. It discusses the physiological and thermodynamic
changes that occur under high pressure, the
compensatory mechanisms in the brain, and the potential
consequences of these changes, such as cognitive
impairments and more severe symptoms like nausea and
seizures.
Authors: David M. Eckmann, & Stephen C. Armstead
This study investigates the effects of exogenous
surfactants on the restoration of blood flow following the
degradation of the endothelial glycocalyx, testing the
hypothesis that different surfactants have varying impacts
on the rate of blood flow restoration after glycocalyx
damage. It also details the methods, results, and
conclusions of the study, highlighting the potential clinical
implications of using surfactants to reduce embolism
bubble adhesion in cases of glycocalyx disruption.
6 - La plongée: pression barométrique et mécanismes
neurochimiques
- Published by Biologie Aujourd'hui (Author-released)
Authors: Jean-Claude Rostain & Norbert Balon
Paul Bert's studies in 1878, detailed in "La Pression
Barométrique," laid the foundation for modern hyperbaric
physiology by demonstrating the effects of oxygen at high
pressure. He found that decompression issues could
cause neurological problems in divers. In 1935, Behnke et
al. linked complaints at 3 bars and above to nitrogen
narcosis. The traditional view suggested narcosis was due
to gas absorption in membranes, but recent protein
theories suggest direct interactions with gas-protein
receptors. The question remains whether inert gases
disrupt neurotransmitter functions by binding to these
receptors.
2 - Accidents en plongee subaquatique en milieu hyperbare
- Published by EM Consult - Elsevier (Author-released)
Authors: J.-E. Coulange, J.-E.Blatteau, O. Le Pennetier, F.
Joulia, P. Constantin, A. Desplantes, A. Henckes,
V. Lafay, A. Kauert, R. Pignel, B. Barberon, P.
Louge, A. Barthélémy
This document describes the various diving accident hat
may happen to recreational divers or young commercial
divers.
Note that this document is written in French
