scientific-2013

Scientific papers 2013

Most diving companies use the protocol proposed and tested by Dr. E. Thalmann (US Navy) to fight otitis externa that affects numerous saturation divers. This method reduces the rate of infections from 75% to 0%. However, it has been observed that some divers experience side effects from this treatment. These side effects include erythema and cracking of the outer ear canal to crystallization throughout the external canal and on the tympanic membrane. This document from the US Navy Experimental Diving Unit discusses a new protocol to avoid these side effects without diminishing the treatment's efficiency initially promoted by Dr. Thalman.

22 - Submarine Rescue Decompression Procedure from Hyperbaric Exposures up to 6 Bar of Absolute Pressure in Man: Effects on Bubble Formation and Pulmonary Function.

Authors: Jean-Eric Blatteau, Julien Hugon, Olivier Castagna, Cédric Meckler, Nicolas Vallée, Yves Jammes, Michel Hugon, Jan Risberg, and Christophe Pény. Abstract: Recent advances in submarine rescue systems have allowed a transfer under pressure of crew members rescued from a disabled submarine. The choice of a safe decompression procedure for pressurized rescuees has been previously discussed, but no schedule has been validated when the internal submarine pressure is significantly increased, i.e., exceeding 2.8 bar absolute pressure. This study tested a saturation decompression procedure from hyperbaric exposures up to 6 bar, the maximum operating pressure of the NATO submarine rescue system. The objective was to investigate the incidence of decompression sickness (DCS) and clinical and spirometric indices of pulmonary oxygen toxicity.

This document provides summaries of the 86 topics discussed during this meeting.

Abstract: In medical emergencies, supplemental oxygen is often administrated routinely. Most paramedics and physicians believe that high concentrations of oxygen are life-saving. Over the last century, however, a plethora of studies point to the possible detrimental effects of hyperoxia induced by supplemental oxygen in a variety of medical emergencies. This viewpoint provides a historical overview and questions the safety of routine high-dose oxygen administration and is based on pathophysiology and (pre)clinical findings in various medical emergencies.

Authors: O. Castagna, J. E. Blatteau, N. Vallee, B. Schmid, J. Regnard. This study aimed at demonstrating that the neoprene wetsuit provides not only thermal protection. The compression it exerts on the diver’s shell significantly impacts hydromineral homeostasis by restraining the systemic vascular capacity and secondarily increasing urine output on dry land and during scuba diving.

Authors: Stephen R. Thom, Tatyana N. Milovanova, Marina Bogush, Ming Yang, Veena M. Bhopale, Neal W. Pollock, Marko Ljubkovic, Petar Denoble, Dennis Madden, Mislav Lozo, and Zeljko Dujic. The study goal was to evaluate responses in humans following decompression from open-water SCUBA diving with the hypothesis that exertion underwater and use of a breathing mixture containing more oxygen and less nitrogen (enriched air nitrox) would alter annexin V- positive microparticle (MP) production and size changes and neutrophil activation, as well as their relationships to intravascular bubble formation.

Authors: Jean-Eric Blatteau, Alf O. Brubakk, Emmanuel Gempp, Olivier Castagna, Jean-Jacques Risso, Nicolas Vallee. The use of sildenafil, a well-known phosphodiesterase-5 blocker, which acts by potentiating the vasodilatory effect on smooth muscle relaxation, has never been studied in DCS. The purpose of the present study was to evaluate the clinical effects of sildenafil pre-treatment on DCS in a rat model. Sixty-seven rats were subjected to a simulated dive at 90 msw for 45 min before staged decompression.

Authors: Nicolas Vallée, Sandrine Gaillard, André Peinnequin, Jean- Jacques Risso, & Jean-Eric Blatteau. The use of sildenafil, a well-known phosphodiesterase-5 blocker, which acts by potentiating the vasodilatory effect on smooth muscle relaxation, has never been studied in DCS. The purpose of the present study was to evaluate the clinical effects of sildenafil pre-treatment on DCS in a rat model. Sixty-seven rats were subjected to a simulated dive at 90 msw for 45 min before staged decompression.

30 - Relation between cervical and thoracic spinal canal stenosis and the development of spinal cord decompression sickness in recreational scuba divers.

Authors: E Gempp, P Louge, T Lafolie, S Demaistre, M. Hugon, JE. Blatteau. This study investigate the relationship between vertebral degenerative changes resulting in spinal canal, spinal cord lesions, and the devellopment of spinal cord decompression sickness (DCS) in scuba divers.

This document is taken into reference by scientists performing experimentations. The World Medical Association (WMA) serves as a clearinghouse of ethics information resources for its members. The WMA cooperates with academic institutions, global organizations, and individual experts to achieve this goal. The documents it publishes are recognized as the international ethical standard for the topics they address.

Authors: D. J. Harriss, G. Atkinson The ethical standards indicated in this document are also taken into reference by scientists performing experimentations.

Authors: Marco B. Hansen, Tejs Jansen, Michael B. Sifakis, Ole Hyldegaard , Erik C. Jansen. This study evaluated the feasibility and safety of using nitrox 50 as breathing gas during attendance in a hyperbaric chamber. Paper logs were reviewed to analyze nitrogen gas- loading, actual bottom time, total bottom time, and surface interval time. With the Norwegian Diving Tables, nitrogen gas-loading was converted to repetitive group Letters. Symptoms of decompression sickness and health problems related to hyperbaric exposures were registered at weekly staff meetings. The chamber personnel breathed chamber air or Nitrox 50.

Authors: Dylan Thompson, Alan M. Batterham There has been some discussion of whether it is possible to score highly in one dimension of physical activity behaviour (e.g., moderate-intensity exercise) while scoring poorly in another (e.g., sedentary time). Interestingly, direct empirical observations to support these proposals are lacking. New technologies now capture physical activity thermogenesis on a minute-by-minute basis and over a sustained period. The authors used one of the best available technologies to explore whether individuals can score differently in various physiologically-important physical activity dimensions.

Authors: Virginie Papadopoulou, Robert J. Eckersley, Costantino Balestra, Thodoris D. Karapantsios, Meng-Xing Tang. Bubbles are known to form in the body after scuba dives, even those done well within the decompression model limits. These can sometimes trigger decompression sickness, and the dive protocols should therefore aim to limit bubble formation and growth from hyperbaric decompression. Understanding these processes physiologically has been a challenge for decades, and there are a number of questions still unanswered. The physics and historical background of this field of study are presented, and the latest studies and developments are reviewed.

Authors: Sigrid Theunissen, Julie Schumacker, Franc¸ois Guerrero, Frauke Tillmans, Antoine Boutros, Kate Lambrechts, Aleksandra Mazur, Massimo Pieri, Peter Germonpre, & Costantino Balestra The aim of this study is to observe the effects of dark chocolate on endothelial function after a series of successive apnea dives in non-thermoneutral water.

Authors: Ibiam Fa, Obasikene Godwin, Basil Ezeanolue Several agents involving mono or multi-therapy have been used over the years in the treatment of acute otitis externa with varying results. In this study The authors considered the response pattern of acute otitis externa to a tripple regimen of steroid, antibacterial and an anti- fungal medication in our center.

Authors: Dorota Kaczerska, Piotr SiermontowskiOlszansk, Karolina Krefft, Sylwia Małgorzewicz, Katarzyna Van Damme- Ostapowicz Cases of decompression sickness are observed despite the correct application of decompression tables. For this reason, this study investigated factors affecting the safety of diving, with a particular emphasis on diet, which, thus far, has not been taken into account.

Authors: David J. Doolette, Wayne A. Gerth Inner ear decompression sickness (DCS) has followed deep breathing gas switches to air (or other nitrogen- oxygen mixtures) during decompression from deep heliox dives. This study investigates the safety of heliox-to-air breathing gas switches at moderate depths.

Authors: Andrea Cortegiani, Grazia Foresta, Giustino Strano, Maria Teresa Strano, Francesca Montalto, Domenico Garbo, and Santi Maurizio Raineri Some cases of decompression illness are known to have occurred among breath-hold (BH) divers also, and they are reported in the medical literature. A male BH diver (57 years old), underwater fishing champion, presented neurological disorders as dizziness, sensory numbness, blurred vision, and left frontoparietal pain after many dives to a 30–35 meters sea water depth with short surface intervals.

Authors: Xavier CE Vrijdag, Pieter-Jan AM van Ooij, and Robert A van Hulst This study evaluates the benefits of argon, compared to air, as a thermal insulation gas for a dry suit during a 1-h cold-water dive by divers of the Royal Netherlands Navy.

Authors: Arve Jørgensen, Philip P. Foster, Alf O. Brubakk, & Ingrid Eftedal The aim of this study was to investigate the effect of diving-induced venous gas emboli (VGE) formation on cardiac stress marker levels and the cardioprotective effect of hyperbaric oxygen preconditioning (HBO-PC). To induce high loads of VGE, 63 female Sprague – Dawley rats were subjected to a rapid ambient pressure reduction from a simulated saturation dive (50 min at 709 kPa) in a pressure chamber.

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Authors: Thomas Randsoe and Ole Hyldegaard High altitude can cause decompression sickness (DCS). Studies have shown that venous gas embolism (VGE) and DCS incidence rise sharply when ambient pressure exceeds 40–44 kPa. Moreover, experiments suggest that these bubbles can grow and stabilize at 25 kPa, but tend to shrink and disappear at 71 kPa when breathing oxygen. The authors hypothesize that a specific ambient pressure threshold, between 25 and 71 kPa, may determine whether these bubbles stabilize or disappear. The results showed that more bubbles shrank and disappeared at 60 and 47 kPa than at 36 kPa.

Authors: Kate Lambrechts, Jean-Michel Pontier, Aleksandra Mazur, Peter Buzzacott, Jean Morin, Qiong Wang, Michael Theron, & Francois Guerrero This study explored post-dive vascular dysfunction mechanisms in divers using three protocols: a 30-minute SCUBA dive at 400 kPa, a 41-minute seawater surface finning exercise, and a 41-minute simulated dive with 100% oxygen at 170 kPa. Doppler-monitored bubble grades and vascular function were assessed. The results showed no significant change in endothelium-dependent reactivity after the SCUBA dive, but there was a notable decrease in endothelium-independent response.

Authors: Ji Won Park, Barbora Piknova, Paul L. Huang, Constance T. Noguchi, Alan N. Schechter This document presents the findings of a scientific study that investigates the role of dietary nitrite and nitrate in regulating platelet function and their potential impact on thrombosis and hemostasis. It explores how manipulating nitrite and nitrate levels in mice through various methods, including diet and supplementation, affects platelet aggregation, ATP release, and bleeding time. The results suggest that endogenous nitrite and nitrate levels could serve as biomarkers for predicting platelet function and that dietary changes may influence thrombotic processes.

Authors: Anke Neidig, Amy T.Y. Yeung, Thibaut Rosay, Beatrix Tettmann, Nikola Strempel, Martina Rueger, Olivier Lesouhaitier, and Joerg Overhage This paper presents scientific research findings on the role of the TypA GTPase in the virulence of Pseudomonas aeruginosa. It outlines the background of the study, the experimental results, and the conclusions drawn from the research. Specifically, it aims to communicate that mutation of the typA gene in P. aeruginosa leads to reduced virulence, impaired biofilm formation, and decreased antibiotic resistance, thereby identifying TypA as a significant modulator of the pathogen's virulence.

Authors: Sigrid Theunissen, Nicola Sponsiello, Miroslav Rozloznik, Peter Germonpré, François, Guerrero, Danilo Cialoni and Costantino Balestra This paper discusses a scientific study that investigates the effects of repetitive breath-hold diving on plasma oxidative stress markers. It analyzes how such diving activities influence levels of nitric oxide (NO), peroxynitrite (ONOO–), and thiols (R-SH) in the blood to understand the physiological changes and oxidative stress associated with breath-hold diving.

Authors: Ingrid Eftedal, Marko Ljubkovic, Arnar Flatberg, Arve Jørgensen, Alf O. Brubakk, and Zeljko Dujic This study investigates the physiological effects of scuba diving on the human circulatory system, specifically focusing on the changes in the blood transcriptomes of experienced divers. The study aims to identify genes, biological pathways, and cell types that are affected by the stress of scuba diving, even in the absence of symptoms. The research involves analyzing blood samples from divers before and after a series of dives, comparing them to non-divers, and identifying significant changes in gene expression related to apoptosis, inflammation, and immune responses.

29 - Functional comparison between critical flicker fusion frequency and simple cognitive tests in subjects breathing air or oxygen in normobaria

Authors: Walter Hemelryck, Miroslav Rozloznik, Peter Germonpré, Costantino Balestra and Pierre Lafère This study evaluates the reliability of using critical flicker fusion frequency (CFFF) to measure cognitive function, particularly in the context of inert gas narcosis, comparing CFFF with other cognitive tests to assess the impact of breathing 100% normobaric oxygen on mental performance. The results suggest that CFFF is a reliable measure that correlates with other cognitive tests and could be used in various operational environments, such as diving. The authors conclude by suggesting further research to explore the effects of different pressures and gas mixtures on cognitive function during diving.

03 - Patent foramen ovale and scuba diving: a practical guide for physicians on when to refer for screening

Authors: Oliver Sykes, and James E Clark Divers learn basic physiology in training, leading to concerns about patent foramen ovale (PFO) and decompression illness (DCI). While routine PFO screening for all divers is not recommended, guidelines for selective screening are unclear. The text provides information on existing guidelines, advice for management, and suggests which divers should consider PFO screening.

Author: Neal W. Pollock, Jaksa Zanchi, Marko Ljubkovic, Petar J. Denoble, Zeljko Dujic, Shabbar I. Ranapurwala Presentation made for the Aerospace Medical Association in May 2013

11 - Influence of repeated daily diving on decompression stress

14 - A critical review of physiological bubble formation in hyperbaric decompression

Authors: Virginie Papadopoulou, Robert J. Eckersley, Costantino Balestra, Thodoris D. Karapantsios, Meng-Xing Tang This document discusses ongoing challenges in understanding these processes and reviews past studies and recent developments. Heterogeneous nucleation is a key factor in bubble formation, affected by surface hydrophobicity and tissue elasticity. The relevance of modeling bubble formation, growth, and multiple bubble behavior is also addressed.

15 - Exercise after SCUBA diving increases the incidence of arterial gas embolism.

Author: Dennis Madden, Mislav Lozo, Zeljko Dujic, and Marko Ljubkovic This study aimed to check if post-diving exercise raises the rate of arterialization. After a dive, subjects were monitored for bubbles at rest and during an exercise test. Results showed that exercise increased arterialization from 13% at rest to 52%, confirming that individuals can arterialize through IPAVA and that the exercise intensity affects this process.

16 - Influence of Repeated Daily Diving on Decompression Stress

Author: J. Zanchi, M. Ljubkovic , P. J. Denoble, Z. Dujic, S. Ranapurwala, N. W. Pollock Acclimatization to diving may lower decompression stress by reducing post-dive gas bubbles. This study examined if four days of daily diving affected bubble grades. Sixteen male divers completed the same dives over four days, with monitoring of bubble grades. Results showed that the likelihood of higher bubble grades decreased on subsequent days, indicating that repeated diving could lead to positive acclimatization. Further research is needed to assess longer diving durations and their effects on decompression sickness risk.

24 - Mathematical Models of Diffusion-Limited Gas Bubble Evolution in Perfused Tissue.

Author: Ramachandra Srini Srinivasan, Wayne A. Gerth This study aimed to check if post-diving exercise raises the rate of arterialization. After a dive, subjects were monitored for bubbles at rest and during an exercise test. Results showed that exercise increased arterialization from 13% at rest to 52%, confirming that individuals can arterialize through IPAVA and that the exercise intensity affects this process.

25 - Barodontalgias, dental and orofacial barotraumas

Author: Cristina Zanotta, Dorothea Dagassan, Peter Nussberger, Tuomas Waltimo, Andrea Filippi This study focuses on dental and orofacial problems caused by pressure variations. A survey of 520 pressure- exposed individuals revealed 15% had dental issues, with toothaches reported by 10. 2% and tooth injuries by 6. 3%. Recommendations for preventing barotraumas in divers and caisson workers were created.