Scientific papers 2006
Next page Next page BUTTON TEXT Previous page Back to the menu 16 - Gisele ML Mouret: Obesity and diving.
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.
17 - The effects of air bubbles on ultrasound velocity measurements.
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.
19 - Handbook on Hyperbaric Medicine.
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.
12 - Gas nuclei, their origin, and their role in bubble formation. 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.
9 - Pre-treatment with hyperbaric oxygenation reduces bubble formation and platelet activation
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.
7 - Dehydration Effects on the Risk of Severe Decompression Sickness in a Swine Model
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.
18 - Short oxygen prebreathing and intravenous perfluorocarbon emulsion reduces morbidity and mortality in a swine saturation model of decompression sickness.
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.
2 - Effects of 30m nitrox saturation dive on the immune system in man
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.
15 - To Burn or not burn - High oxygen mixtures.
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.
5 - Venous bubble count declines during strenuous exercise after an open sea dive to 30 m.
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.
14 - Modelling and Measurement of Bubbles in Decompression Sickness.
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.
6 - Exogenous Nitric Oxide and Bubble Formation in Divers.
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.
26 - Incidence of Ischemic Brain Lesions in Hyperbaric Chamber Inside Attendants.
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.
21 - The SANDHOG criteria and its validation for the diagnosis of DCS arising from bounce diving.
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.
24 - CNS oxygen toxicity in closed-circuit diving: Signs and symptoms before loss of consciousness
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.
20 - The relative safety of forward and reverse diving profiles
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.
4 - Proceeding of advanced scientific diving workshop
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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1- Genetic AVP deficiency abolishes cold-induced diuresis but does not attenuate cold-induced hypertension
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.
3 - Dehydration Effects on the Risk of Severe Decompression Sickness in a Swine Model
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.
8 - Nitric oxide amplifies the excitatory to inhibitory neurotransmitter imbalance accelerating oxygen seizures
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.
10 - Hyperoxic and hyperbaric-induced cardioprotection: Role of nitric oxide synthase 3
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.
11 - Contribution of thermal and nonthermal factors to the regulation of body temperature in humans
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.
13 - Effect of a short-acting NO donor on bubble formation from a saturation dive in pigs
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.
22 - Neurological manifestations of decompression illness in recreational divers - the Cozumel experience
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.
23 - The effects of acute oral antioxidants on diving-induced alterations in human cardiovascular function.
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.
25 - Decompression sickness in the rat following a dive on trimix: recompression therapy with oxygen vs. heliox and oxygen
Authors: R. Arieli, P. Svidovsky, & A. Abramovich This study examines the use of Trimix (helium, nitrogen, and oxygen) in deep diving to reduce high-pressure nervous syndrome and decompression time. Rats were exposed to Trimix in a hyperbaric chamber and tested for decompression sickness (DCS). Rats weighing 100–150 g did not suffer from DCS, but the risk increased with body mass for rats weighing 200–350 g. Death and most DCS symptoms occurred during the 30-minute walking period. Immediate hyperbaric oxygen (HBO) treatment reduced the death rate to zero, while a 5-minute delay in treatment resulted in death rates of 25% with HBO and 20% with heliox.