Scientific papers 1976 - 1979
In association with Hennessy, Hempleman developed a
complex formula taking into account the diffusion, the
surface tension around the bubble, the elasticity of tissues,
the perfusion, the voltage of the gas in the liquid to
describe the magnification of bubbles and their circulation
in the body.
In contrast to the Haldane model, it is considered that the
gas diffuses through the alveolar walls to dissolve in the
blood and broadcasts also in cartilage (only organic fabrics
retained in the model). This model is said “by diffusion”
Author: David E. Yount
The Variable Permeability Model (VPM) posits that
“nuclei” or gas pockets occur in the natural state and may
develop from the gas nucleus trapped in small
hydrophobic crevices or be generated by tribonucleation.
It is thought that the surface tension at the external
surface of the bubble creates a sort of “skin”, which is the
interface between the free gases inside the bubble and
the liquids/dissolved gases in the tissue compartments.
The skin of the bubble can be compared to an elastic
membrane with microscopic holes that close gradually as
the bubble shrinks and open progressively as the bubble
grows: the permeability of the bubble varies, which is why
this model is called the “Variable Permeability Model”.
This document is the final report of a workshop performed
on the 13 and 14 of November 1979 under the direction
of Professor Lambertsen and Doctor Bornmann.
Author: Brian A. Hills
This article was written to support the famous book
“Decompression Sickness: The Biophysical Basis of
Prevention and Treatment” (published by John Wiley in
New York and London), where the Thermodynamic
approach was explained in detail.
It describes the problems arising with decompression and
their approach by Brian Hills.
Author: Brian A. Hills
In this article, Brian Hills described the implication of
supersaturation and counterdiffusion for bubble
formation. He said that it could explain the occurrence of
decompression sickness when decompression is normally
not called for.
Authors: C.J. Lambertsen, J.M. Clark, & R. Gelfand
This document, published in 1978, describes
experimentations made during the seventies in support of
US Navy and the NASA activities with the particiaton of
the University of Pennsylvania, the U.S. Naval Medical
Research Institute, the U.S. Naval Submarine Medical
Center, the NASA Manned Spacecraft Center, the
University of Florida at Gainesville, and the Virginia Mason
Hospital at Seattle.
Authors: Dueker CW, Lambertsen CJ, Rosowski JJ,
Saunders JC
This study discusses the occurrence of incapacitating
vestibular dysfunction in men breathing mixes such as
nitrogen-helium-oxygen or neon-helium-oxygen mixtures
while surrounded by helium.
These symptoms were identified along with dermal gas
lesions and continuous venous gas embolization as part of
the isobaric counterdiffusion phenomenon, which is a
significant hazard in manned undersea activities.
Author: Edvard A. Hemmingsen.
Various solutions of surfactants and electrolytes were
equilibrated with argon at gas pressures up to 202 atm
and then decompressed to atmospheric pressure while
observed visually or cinematographically for the
occurrence of bubbles.
Authors: Kent H Smith & Lee Stayon
Using the Doppler detector implanted on the pulmonary
artery or posterior vena cava in sheep and goats, the team
demonstrated the presence of gaseous emboli in all
Haldane model.
Decompression limits for compressed air determined by
ultrasonically detected blood bubbles.
The direct decompression limits for a group of divers over
a range of pressure-time air exposures was determined
using ultrasonic detection of venous gas emboli (VGE). In
addition to dry chamber exposures, ranging from 233 ft
for 7 min to 25 ft for 720 min, the authors exposed six
divers to open ocean dives at 165 ft for 10 min. Findings
demonstrated a strong individual propensity to form
VGE, correlating with susceptibility to bends.
Authors: John B Hartley, George m Santangelo, Howard
Rasmussen, Howard Goldfine
This study examined membrane-related oxygen poisoning
in Escherichia coli K1060 and its parent strain, K-12 Ymel. It
concluded that the kinetics of oxygen toxicity in E. coli are
dependent upon the particular unsaturated fatty acyl
chain composition of the membrane, that the membrane
composition influences the rate-limiting step in hyperbaric
oxygen toxicity, but that a direct structural effect of
hyperbaric oxygen on the membrane lipid, such as
oxidation of the unsaturated acyl chain moiety, is unlikely
in these cells.
Authors: T.E Berghage, J.Voromasti, E.E.P Barnard
This article reviews the US Navy and other recompression
procedures used throughout the world in 1978.
Author: Thomas E. Berghage
This document from the Undersea Medical Society
reports discussions logged during a Workshop held in
September 1978 and supported by the US Office of Naval
Research.
The participants were the most advanced US scientists in
decompression theory at this time.
Authors: H. Le Messurier, T. N. Smith, and W. r. Wood
The authors developed a model for behavior of specimens
in gel, and conformity with the results of an
experimentation program was demonstrated. With the
insight provided by this model, a substantial analogy
between important aspects of the behavior of gel and
tissue was claimed, and application of this model to the
refinement and development of diving and
decompression procedures was proposed.
Authors: Wayne A. Gerth & Edward A. Hemmingsen
Spontaneous cavitation is considered as a potential cause
of decompression accidents. Water with high gas
supersaturation can be stable without cavitation, but
increased supersaturation can lead to system failure and
bubble formation. The concentration of a gas in a solution,
which is influenced by its solubility, plays a significant role
in determining the stability of gas supersaturation in
liquids.
Authors: B. Gardette, A. Ternisien
This key document, written in French, summarizes
experimentations made by Comex on the use of Dopplers
during the years 1976 & 1977.
These operations led to the improvement of devices and
their corresponding procedures for use.
Authors: Louis D Homer, R. Clifton Bailey
Doctors Homer and Bailey conducted extensive research
on statistics for the US Navy.
This paper presents an approach to maximum likelihood
estimation (MLE) using analogies. The resulting algorithm
offers a direct and general approach to Maximum
Likelihood Estimation, simplifying the estimation process,
especially when dealing with complex likelihood functions.
Authors: William L. Hunter, Gene B. Pope, Danny A. Arsu
This document, published in 1978, aimed to improve US
Navy diving procedures. Although the incidence rate of
decompression sickness was below 0.1%, which was
considered low, it was acknowledged that accidents still
occurred and needed to be prevented.
Authors:
W.H. Spaur, E.D. Thalmann, E.T. Flynn, J.L. Zunirick, T.W.
Reedy, and J. M. Ringelberg
This document discusses experiments performed during
helium-oxygen saturation dives ranging from 150 to 1000
fsw to study the limits of multiple and extended-duration
excursions, both deeper and shallower than the storage
depth.
It was found that the distance a diver can safely ascend
without decompression is a function of depth, increasing
from 75 feet at a saturation depth of 225 feet to 180 feet
at I000 feet. Also, initiating saturation decompression
immediately after an excursion was considered safe.
This workshop, organized by the Undersea and Hyperbaric
Medical Society (UHMS), and held in Bethesda, Maryland,
from September 6 to 7, 1978, explored the complexities of
decompression theory and provided a platform for
collaboration and knowledge exchange. The Office of
Naval Research supported it.
Although the official proceedings remain a valuable
resource, the spirit of inquiry and exploration still shapes
our understanding of underwater medicine and safety.
Authors: K.E. Kidman, G. Masurel, R. Guillerm
This document explains how to establish a databank
containing Doppler ultrasonic bubble flow data obtained
during and after the decompression of divers.
This databank can serve as a foundation for future
computer correlation studies.
Author: Thomas D. Kunkle
This document pertains to experiments on the formation
of bubbles when gas dissolves in liquid and becomes
supersaturated.
The findings are that:
•
Viscosity significantly influences bubble growth.
•
Pressure and diffusion also affect the bubbles' behavior
and the gas transfer rate.
•
The solubility of the gas also plays a crucial role in the
dynamics of bubbles.
Authors: Murray Epstein
This study examines the physiological changes that occur
in the cardiovascular and renal systems when the human
body is immersed in water up to the neck, also known as
head-out water immersion. It was found that head-out
water immersion increases central blood volume, cardiac
output, peripheral vascular resistance, glomerular filtration
rate, and urine output. That demonstrates that head-out
water immersion can be used as a model to assess the
body's ability to maintain a stable fluid balance.
Authors: Banks Anderson, Joseph C. Farmer
Patients at the Duke hyperbaric facility reported vision
blurring after repeated hyperoxic exposures, unlike
attendants who breathed air and noted no visual
disturbances. Investigations revealed that this blurring was
due to myopia, which increased during hyperoxic
exposure and gradually returned to normal after
treatment ended.
Authors: T. Balazs & V. J. Ferrans
Chemically induced cardiomyopathies often result from a
cardiac metabolic imbalance due to exaggerated
functional effects, such as those caused by adrenergic
beta-receptor stimulants and vasodilating
antihypertensives. Another type of toxic cardiomyopathy
arises from direct cardiotoxic mechanisms unrelated to
cardiovascular functional effects, exemplified by
cardiomyopathy caused by anthracycline antineoplastic
agents. The text discusses these cardiomyopathies'
pathogenesis, morphological changes, and toxicologic
features, focusing on their detection in preclinical toxicity
studies.
Authors: M.G. Hayward, W.R. Keatinge
This study describes an instance of progressive
symptomless hypothermia that developed during a fully
monitored laboratory experiment aimed at assessing
individual responses to mild surface cooling in water.
Authors: Britton Chance, Helmut Sies, & Alberto Boveris.
This study established a quantitative framework for redox
systems biology, which examines the roles of reduction-
oxidation (redox) reactions in biological systems. It made
seminal discoveries about hydrogen peroxide metabolism
and its role in redox biology
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Authors:
James W. Miller, George M Adams, Peter B. Bennett,
Richard E. Clarke, Robert W. Hamilton, David J. Kenyon,
Robert I Wicklund
This 1976 paper offers a thorough overview and
documentation of the prevailing practices and research
concerning hyperbaric saturation exposures utilizing air or
nitrogen-oxygen mixtures. It aims to emphasize the
application of vertical excursions in these exposures,
delineate pertinent laboratory and field projects, and
discuss notable results and applications. Furthermore, it
endeavors to evaluate current capabilities and pinpoint
areas requiring further investigation.
Janus 4 is notable for achieving an open-sea dive to a
depth of 460 metres (1510feet) in 1977, which was a
remarkable feat at the time. This document outlines the
successful completion of the first phase, which involved
testing the physiological suitability of candidates, and the
goals of the second phase, which include simulating
actual sea conditions, living in confined spaces at great
depths, and training the divers involved in the program.
Authors: Brian A, hills
The purpose of this paper is to discuss and analyze the
mechanisms of decompression sickness, focusing on the
underlying physiology and physics to improve prevention
and treatment methods. It emphasizes a detailed
examination of what occurs within the body during
decompression sickness, rather than solely relying on the
occurrence of symptoms to evaluate procedures. It also
mentions specific categories of decompression sickness,
such as limb bends and air embolism, and considers
factors that might enhance neurological symptoms. In
addition, it explores calculations to prevent Type II
decompression sickness and methods for predicting and
detecting pulmonary oxygen toxicity.
Authors: BA Hills, and BD Butler
This study focused on 70 kangaroo rats trapped in West
Texas to investigate decompression sickness. It found that
tail biting in these rats can model marginal limb bends
seen in humans, and this can be reversed by
recompression. It also showed that the most susceptible
20% of the rats could mimic human decompression limits
for various exposure times with air and helium-oxygen.
The kangaroo rat's characteristics make it a convenient
and cost-effective model for testing decompression
sickness prevention methods..
30 - The kangaroo rat as a model for Type I decompression sickness
- Published by the Undersea & Hyperbaric Medical Society
This paper addresses critical issues related to medical
ethics and the protection of human rights in the context
of medical experimentation. It explores the ethical
principles and guidelines necessary to ensure that medical
research involving human subjects is conducted in a
manner that respects and protects their rights and dignity.
The discussions and findings presented in this paper are
part of CIOMS' ongoing efforts to establish international
ethical standards for biomedical research.
31 - Medical experimentation and the protection of human right
- Published by the Council for international organization of medical sciences (CIOMS)
Author: GM Gauthier
Vestibulo-ocular reflex (VOR) gain was measured in two
professional divers during a simulated dive at 62 ATA. The
divers were rotated sinusoidally while tests were
conducted before, during, and after pressure changes.
Results revealed no spontaneous nystagmus but noted
two significant changes in VOR gain: a slight increase
during pressure elevation, potentially indicating
heightened vestibular system excitability or reduced
cerebellar inhibition, and an intermittently appearing
increase in VOR gain (values between 1 and 1.3) during
brief periods, attributed to adaptations from using
magnifying optical systems in diving.
Author: DH Elliott
Diving is a high-risk profession, with reports of 26 deaths
among approximately 1,000 North Sea divers over the last
4-5 years, primarily attributable to equipment failure or
procedural errors. Fatalities linked to decompression
sickness were minimal, and various incidents resulted in
neurological deficits or chronic conditions like aseptic
necrosis of the bone. While certain risks stem from diving
equipment and procedures, medical practitioners also play
a role in hazard reduction. Physiological effects of pressure
and gas mixtures can lead to a range of issues, varying
during compression and decompression phases.
Authors: Aaron P Sanders, & William D Currie
This study focuses on understanding acute central
nervous system oxygen toxicity by examining enzyme
activities and levels of protective metabolites in rats during
air and high-pressure oxygen exposures. Researchers
found decreased concentrations of several key
metabolites in rats exposed to 5 ATA oxygen for 60
minutes, which is when convulsions begin. They noted
decreased activity in certain enzymes, suggesting that
early oxygen toxicity affects ATP production due to
inhibited enzyme systems. When protective agents were
administered, convulsions occurred later, indicating a
problem with ATP utilization.
Author: J L Hart
This study examined how aspirin and acetaminophen
affect fevers in rats under hyperbaric helium-oxygen
conditions. The researchers tested different doses of each
drug in normal air and in high-pressure helium. They
found that both drugs worked less effectively in hyperbaric
helium; acetaminophen's effects were reduced by 73%,
and lower doses of aspirin by 56%. The highest dose of
aspirin raised temperatures significantly. The reduced
effectiveness is likely due to high ambient temperatures in
helium, which affects the rats' ability to regulate heat.
Authors: SP Gruenau & MJ Ackerman
Previous studies identified two tremor systems: thalamo-
cortical (4-8 Hz low-frequency) and olivo-cerebellar (10-18
Hz high-frequency). This study tested their role in HPNS
tremor via leg recordings and power spectral analysis in 8
guinea pigs compressed to 61.6 ATA in helium-oxygen.
Results revealed a biphasic pattern: a low-power 4-6 Hz
component up to ~31 ATA, followed by abrupt
emergence of a high-power 12-18 Hz component from
~34 ATA onward, producing coarse tremors. The high-
frequency component subsided within minutes at
maximum pressure. Findings support that HPNS tremor
involves two components, possibly from separate systems.
Authors: FM Davis, AD Braddeley, and TR Hancock
Fifteen divers performed five tasks in 20°C and 5°C water
using scuba gear. Cold caused significant performance
declines: arithmetic 13%, reasoning 17%, recall 37%,
recognition 11%, dexterity 17%. Rectal temperature fell
0.5°C vs 1.1°C and skin temperature 5°C vs 12.5°C, with
heat losses of 95 vs 245 kcal/m²/hr. Word recognition
correlated with core cooling; other impairments occurred
rapidly on immersion. Results are discussed regarding
cold's mechanisms affecting underwater performance.
Author: Robert C. Carter
An experiment with six divers at 427m simulated depth
tested effects of depth, immersion, and repeated testing
on seven cognitive abilities via 10 tests. Results showed
impairments in Perceptual Speed and Number Facility but
improvement in Associative Memory at depth vs sea level;
Hidden Patterns and Division scores rose with repetition.
Causes and diver task design implications are discussed.
