scientific-2018-2019

Scientific papers 2018 - 2019

The documents are classified chronologically from 2018 to 2019. Click on their descriptions to open and download them.

In this document, Wienke & O'Leary attempt a short history of deep and shallow stops by taking into account physical aspects, staging differences, diving tests, models with data correlations, and data banks with user statistics. Pros and cons of deep and shallow stops are presented, and what they consider misfacts are righted. Also, they discuss the various tests, training agency standards, commercial diving operations, and dive software linked to this topic.

49 - Effect of helium preconditioning on neurological decompression sickness in rats. Authors: Rongjia Zhang, Hongda Bi, Ning Zhang, Ting Zhang, Zhouheng Ye, Xuejun Sun, Yongchao Yu, Anatol Manaenko, & Ling Zhang.

Helium Preconditioning (HPC) recently demonstrated beneficial properties against ischemic damage, so the authors hypothesized that this procedure might decrease the neurological deficits of DCS in rats. Following the experimentations described in this report, they found that Helium Preconditioning (HPC) resulted in significantly decreased DCS incidence and delay of DCS onset. It also improved animal performance on the grip test after decompression and ameliorated decompression- induced decrease of platelet number. Furthermore, the incidence of abnormal Somatosensory Evoked Potential (SSEP) waves and histological spinal lesions was reduced by Helium Preconditioning (HPC). They conclude that HPC can decrease the occurrence of DCS and improve decompression-induced neurological deficits..

Authors: Alf O Brubakk, Randi Eidsmo Reinertsen, V. Flook, & S. Koteng Abstract: Reduction in ascent speed and an increase in the O2 tension in the inspired air have been used to reduce the risk for decompression sickness. It was previously reported that decompression speed and O2 partial pressure are linearly related to human decompressions from saturation hyperbaric exposures. The constant of proportionality K (K 5 rate/partial pressure of inspired O2) indicates the incidence of decompression sickness. This study investigated the relationship between decompression rate, partial pressure of inspired O2, and the number of central gas bubbles after a 3-h dive to 500 kPa while breathing nitrox with an O 2 content of 35 kPa.

Authors: Joe KS Leung, Rex PK Lam Hyperbaric oxygen therapy is widely accepted as a life- saving treatment for decompression illness. Yet, its use in acute carbon monoxide poisoning has remained controversial because of inconsistent findings in clinical trials. Hyperbaric oxygen therapy has an adjunctive role in managing gas gangrene, necrotising soft-tissue infection, and crush injury, as supported by the case series. Several cases have been reported in the literature detailing the use of hyperbaric oxygen therapy in patients with severe anemia in whom blood transfusion is not possible.

Authors: Jonathan L. Halbach, James M. Prieto, Andrew W. Wang, Dennis Hawisher, David M. Cauvi, Tony Reyes, Jonathan Okerblom, Israel Ramirez-Sanchez, Francisco Villarreal, Hemal H. Patel, Stephen W. Bickler, George A. Perdrizet, and Antonio De Maio. Sepsis is a major clinical challenge, with therapy limited to supportive interventions. Therefore, the search for novel remedial approaches is of great importance. The authors addressed whether hyperbaric oxygen therapy (HBOT) could improve the outcome of sepsis using an acute experimental mouse model.

Authors: Jean-Pierre Imbert, Costantino Balestra, Fatima Zohra Kiboub, Oyvind Loennechen, & Ingrid Eftedal Commercial saturation diving involves divers living and working in an enclosed atmosphere with an elevated partial pressure of oxygen (ppO2) for weeks. The divers must acclimatize to these conditions during compression for up to 28 days until decompression is completed. During decompression, the ppO2 and ambient pressure are gradually decreased; then, the divers must acclimatize again to breathing normal air in atmospheric pressure when they arrive at the surface. The authors investigated 51 saturation divers’ subjective evaluation of the saturation and post-decompression phase via questionnaires and individual interviews. The questions were about decompression headaches and fatigue and time before recovering to a pre-saturation state.

30 - Static metabolic bubbles as precursors of vascular gas emboli during divers’ decompression: A hypothesis explaining bubbling variability.

Authors: Jean-Pierre Imbert, Salih Murat Egi, Peter Germonpre, & Costantino Balestra. The risk for decompression sickness (DCS) after hyperbaric exposures (such as SCUBA diving) has been linked to the presence and quantity of vascular gas emboli (VGE) after surfacing from the dive. These VGE can be semi-quantified by ultrasound Doppler and quantified via precordial echocardiography. However, for an identical dive, VGE monitoring of divers shows variations related to individual susceptibility, and, for a same diver, dive-to-dive variations, which may be influenced by pre-dive pre-conditioning. These variations are not explained by currently used algorithms. In this paper, we present a new hypothesis: individual metabolic processes, through the oxygen window (OW) or Inherent Unsaturation of tissues, modulate the presence and volume of static metabolic bubbles (SMB) that in turn act as precursors of circulating VGE after a dive.

05- Safety Priorities and Underestimations in Recreational Scuba Diving Operations: A European Study Supporting the Implementation of New Risk Management Programmes

Authors: Serena Lucrezi, Salih Murat Egi, Massimo Pieri, Francois Burman, Tamer Ozyigit, Danilo Cialon, Guy Thomas, Alessandro Marroni, and Melville Saayman. Scuba diving is an important marine tourism sector but requires proper safety standards to reduce the risks and increase accessibility to its market. To achieve safety goals, safety awareness and positive safety attitudes in recreational scuba diving operations are essential. However, there is no published research exclusively focusing on scuba divers’ and dive centres’ perceptions toward safety. This study assessed safety perceptions in recreational scuba diving operations, with the aim to inform and enhance safety and risk management programs within the scuba diving tourism industry.

Authors: Isaac Peña-Villalobos, Ignacio Casanova-Maldonado, Pablo Lois, & Catalina Prieto. This paper does not speak of diving but of hyperbaric oxygen therapy (HBOT) to solve diverse diseases, infections, and tissue injuries. However, this study highlights other therapeutic effects of oxygen than those commonly explained to divers. This study's authors analyze the effects of HBOT on specific aspects of tissue growth, maintenance, and regeneration to provide answers on how this treatment could benefit from combination with regenerative medicine strategies.

Authors: Fatima Z. Kiboub, Costantino Balestra, Øyvind Loennechen, Ingrid Eftedal. Saturation divers are exposed to elevated partial pressure of oxygen (ppO2) in their hyperbaric work environment. Experimental studies indicate that oxygen transport is altered, and the authors previously reported a drop in hematocrit and extensive downregulation of genes involved in blood oxygen transport capacity after decompression from professional saturation diving. This study investigates the initial period of hematological adjustment back to normobaric air after professional saturation diving.

Authors: Gerardo Bosco, Alex Rizzato, Luca Martani, Simone Schiavo, Ennio Talamonti, Giacomo Garetto, Matteo Paganini, Enrico M. Camporesi, and Richard E. Moon. The present study aimed to evaluate the partial pressure of arterial blood gases in breath-hold divers performing a submersion at 40 m. Eight breath-hold divers were enrolled for the trials held at the “Y-40 THE DEEP JOY” pool (Montegrotto Terme, Padova, Italy). Prior to submersion, an arterial cannula in the radial artery of the non-dominant limb was positioned. All divers performed a sled-assisted breath-hold dive to 40 m. Three blood samplings occurred: at 10 min prior to submersion, at 40 m depth, and within 2 min after diver’s surfacing and after resuming normal ventilation. Blood samples were analyzed immediately on site.

Authors: Jean-Eric Blatteau, Sandrine Gaillard, Sébastien De Maistre, Simone Richard, Pierre Louges, Emmanuel Gempp, Arnaud Druelles, Henri Lehot, Jean Morin, Olivier Castagna, Jacques H. Abraini, Jean-Jacques Risso, Circulating mitochondrial DNA (mtDNA) is receiving increasing attention as a danger-associated molecular pattern in conditions such as autoimmunity or trauma. In the context of decompression sickness (DCS), the course of which is sometimes erratic, the authors hypothesize that mtDNA plays a not insignificant role, particularly in neurological type accidents. This study is based on the comparison of circulating mtDNA levels in humans presenting with various types of diving accidents and punctured upon their admission at the hyperbaric facility.

Authors: Alain Boussuges, Guillaume Chaumet, Nicolas Vallée, Jean Jacques Risso & Jean Michel Pontier Previous studies have suggested that the circulatory system was involved in the production of circulatory bubbles after diving. This study was designed to research the cardio-vascular function characteristics related to the production of high bubble grades after diving.

Authors Simin Berenji Ardestani, Vladimir V. Matchkov, Ingrid Eftedal, & Michael Pedersen. The number of divers is rising every year, including an increasing number of aging persons with impaired endothelial function and concomitant atherosclerosis. While diving is an independent modulator of endothelial function, little is known about how diving affects already impaired endothelium. In this study, the authors questioned whether diving exposure leads to further damage of an already impaired endothelium.

Authors: Blair D. Johnson, Morgan C. O’Leary, Muhamed McBryde, James R. Sackett, Zachary J. Schlader, & John J. Leddy. The authors tested the hypothesis that concussed college athletes have attenuated parasympathetic and sympathetic responses to face cooling. The experimentations described in this document were not made with divers. However, the phenomenon described will happen when the face of the diver is exposed to cold water.

Authors: Mitchell D. Frye, Allen F. Ryan, & Arwa Kurabi. Like other documents in our database, this paper describes phenomenons that apply to every person. However, people in charge of diving and ROV teams should be aware of the potential harm of noisy environments during operations and when people are at rest. This paper describes the processes of inflammation and cochlear damage triggered by noise. It also discusses current appropriate treatments.

Authors: Gerardo Bosco, Alex Rizzato, Silvia Quartesan , Enrico Camporesi, Devanand Mangar, Matteo Paganini, Lorenzo Cenci, Sandro Malacrida, Simona Mrakic-Sposta, Sara Moretti, & Antonio Paoli. Central Nervous System Oxygen Toxicity (CNS-OT) is one of the most harmful effects of Enriched Air Nitrox (EAN) diving. Protective factors of the Ketogenic Diet (KD) are antioxidant activity, the prevention of mitochondrial damage, and anti-inflammatory mechanisms. This study investigated whether a short-term KD may reduce oxidative stress and inflammation during a hyperoxic dive.

Authors: Ali Erdal Gunes, Samil Aktas. Complete blood count (CBC) is a routine diagnostic procedure for patients and a part of routine health inspection for healthy individuals. The effect of hyperbaric oxygen (HBO2) therapy on CBC is not known. The objective of this study was to determine the effects of HBO2 on blood parameters in CBC with long-term HBO2 therapy.

46 - Influence of oxygen enriched gases during decompression on bubble formation and endothelial function in self-contained underwater breathing apparatus diving: a randomized controlled study.

Authors: Ivana Šegrt Ribicic, Maja Valic, Joško Božic, Ante Obad, Duška Glavaš, Igor, Glavicic, Zoran Valic. This study aims to assess the effect of a gas mixture composed of 50% nitrogen and 50% oxygen (nitrox 50) or a gas mixture consisting of 1% nitrogen and 99% oxygen (nitrox 99) on bubble formation and vascular/endothelial function during decompression after self-contained underwater breathing apparatus diving.

47 - Gas micronuclei underlying decompression bubbles may explain the influence of oxygen enriched gases during decompression on bubble formation and endothelial function in self-contained underwater breathing apparatus diving

Author: Ran Arieli In a study published in the Croatian Medical Journal, Šegrt Ribicic et al. said that the endothelial function was reduced after diving to a depth of 45 m seawater for a bottom time of 20 m when breathing nitrox containing 50% oxygen, but not when breathing air or nitrox containing 99% oxygen. The authors of this paper claimed this was the opposite of what they expected; it is known that endothelial function is affected by hyperoxia.

Authors: Mikael Gennser, S. L. Blogg, Ola Eiken, and Igor B. Mekjavic Human extravehicular activity (EVA) is essential to space exploration and involves the risk of decompression sickness (DCS). On Earth, the effect of microgravity on physiological systems is simulated in an experimental model where subjects are confined to a 6 degres head- down bed rest (HDBR). This model investigated various resting and exercise regimens for forming venous gas emboli (VGE), an indicator of decompression stress, post- hyperbaric exposure.

Authors: BR Wienke and TR O’Leary The question of bubble regeneration and broadening in the diver under compression-decompression is virtually unanswered and untractable. Effects in vivo have not been measured nor quantified to date and remain unlikely soon. The authors take up this question and suggest hypothetical impacts on diver staging using available data and recent experimental results in the laboratory.

25 - Was the appearance of surfactants in air breathing vertebrates ultimately the cause of decompression sickness and autoimmune dicease?

Author: Ran arieli Pulmonary surfactants are surface-active lipoproteins deposited in clearly deﬁned areas on the luminal aspect of blood vessels. Bubbles nucleate and grow at these spots after decompression from high pressure. Proteins with hydrophobic regions circulating in the blood will adhere to the gas phase-plasma interface. Deformation of their secondary and tertiary conﬁguration will present them as foreign molecules or autoantigens. Components of the intact protein also present in a deformed protein may be recognized as foreign too.

Authors: Danilo Cialoni, Andrea Brizzolari, Michele Samaja, Massimo Pieri, and Alessandro Marroni. Nitric oxide plays an important role in the physiology and pathophysiology of diving, and the related endothelial dysfunction and oxidative stress roles have been extensively investigated. The scope of this study is to investigate the Nitrate and Nitrite concentration and the total plasma antioxidant capacity before, during and after a single SCUBA dive in healthy scuba diving volunteers, as well as to look for evidence of a possible relationship with venous gas bubble formation.

31 - Poland’s path towards decompression realization in underwater works part 2. decompression tables for commercial deep sea diving in Poland

Authors: Stanisław Skrzynski In the article the author presents the specificity of decompression of deep-sea dives in relation to methods used in underwater works, with particular emphasis on commercial diving in our country. In the 50 - 90 m depth zone in the Polish offshore area, decompression was used in underwater works (works below the depth of 50 m) based on tables designed for bell diving. The technical, organizational and formal conditions of these underwater works corresponded to the national diving potential.

27 - Pulmonary Oxygen Toxicity in Navy Divers: A Crossover Study Using Exhaled Breath Analysis After a One-Hour Air or Oxygen Dive at Nine Meters of Sea Water.

Authors: Thijs T. Wingelaar, Pieter-Jan A. M. van Ooij, Paul Brinkman, and Rob A. van Hulst Exposure to hyperbaric hyperoxic conditions can lead to pulmonary oxygen toxicity. Although a decrease in vital capacity has long been the gold standard, newer diagnostic modalities may be more accurate. In pulmonary medicine, much research has focussed on volatile organic compounds (VOCs) associated with inflammation in exhaled breath. In previous small studies after hyperbaric hyperoxic exposure several methyl alkanes were identified. This study aims to identify which VOCs mark the development of pulmonary oxygen toxicity.

Authors: Barbara E. Shykoff & John P. Florian This study examines differential effects of immersion, elevated oxygen partial pressure, and exercise on pulmonary function after series of five daily six-hour dives at 130 kPa (1.3 ATA), with 18 hours between dives.

Author: Pierre Boudinet The author of this study presents a new way of taking into account the dynamics of the gas phase during decompression. This study is based on the analysis of certain hypotheses underlying classical models using Maximal Values (M-Values). The author derives a reduced set of ordinary differential equations, depending only on three empirical parameters. After having explained how the theory is built, the author proposes some values of the parameters that match the known surface M-Values

Authors: T. T. Wingelaar, P. Brinkman , P. J. A. M. van Ooij, R. Hoencamp, A. H. Maitland-van der Zee, M. W. Hollmann, and R. A. van Hulst IAlthough hyperbaric oxygen therapy (HBOT) has beneficial effects, some patients experience fatigue and pulmonary complaints after several sessions. The current limits of hyperbaric oxygen exposure to prevent pulmonary oxygen toxicity (POT) are based on pulmonary function tests (PFT), but the limitations of PFT are recognized worldwide. However, no newer modalities to detect POT have been established. This study hypothesized that Volatil Organic Compounds VOCs might be detected after HBOT.

Authors: Amir Hadanny, Tal Zubari, Liat Tamir-Adler, Yair Bechor, Gregory Fishlev, Erez Lang, Nir Polak, Jacob Bergan, Mony Friedman, and Shai Efrati This study is also purely medical and is published to provide information about the role of Circadian rhythms, which are 24-hour cycles that are part of the body's internal clock, running in the background to carry out essential functions which control many biological processes in the body in both health and disease.

Authors: Amir Hadanny, Tal Zubari, Liat Tamir-Adler, Yair Bechor, Gregory Fishlev, Erez Lang, Nir Polak, Jacob Bergan, Mony Friedman, and Shai Efrati The aim of this study was to evaluate the effect of hyperbaric oxygen therapy (HBOT) on pulmonary functions of patients receiving the currently used HBOT protocol.

41 - In vitro evidence of decompression bubble dynamics and gas exchange on the luminal aspect of blood vessels: Implications for size distribution of venous bubbles

Authors: Ran Arieli In this document, doctor Arieli explains that lung surfactant leaks into the bloodstream, settling on the luminal aspect of blood vessels to create active hydrophobic spots (AHS). As a result, nanobubbles formed by dissolved gas at these AHS are most probably the precursors of gas micronuclei and decompression bubbles.

42 - Pulmonary oxygen toxicity in saturation dives with PO2 close to the lower end of the toxic range — A quantitative approach

Authors: Ran Arieli In this study, doctor Arieli proposes a new Pulmonary oxygen toxicity (POT) index to evaluate the severity of POT, expressed as reduced lung function or the incidence of POT in a group of divers. Note that, as in many studies from doctor Arieli the concept is demonstrated using complex mathematic functions.

44 - Effects of repeated, long-duration hyperoxic water immersions on neuromuscular endurance in well-trained males

Authors: Christopher M. Myers, Jeong-Su Kim , Kevin K. McCully, and John P. Florian This study examined the effects of repeated long-duration hyperoxic water immersions (WIs) at 1.35 atmospheres absolute (ATA) on neuromuscular endurance performance. its authors hypothesized that over five days of consecutive, resting, long-duration hyperoxic WIs, there would be a decrease in neuromuscular endurance performance and tissue oxygenation with the quadriceps muscle but not with the forearm flexors

48 - Calculated risk of pulmonary and central nervous system oxygen toxicity: A toxicity index derived from the power equation

Author: Ran Arieli Doctor Areli introduced his concept as follows: The concept of the unit pulmonary toxic dose (UPTD), which is based on a modification of the rectangular hyperbola, was proposed in response to a request for oxygen exposure limits based on a very small amount of research data: a point at four atmospheres absolute (atm abs) (405.2 kPa) and the absence of known injury at an inspired partial pressure of oxygen PO2 of 0.5 atm abs (50.6 kPa). It was merely descriptive, without any basis in physico-chemical or physiological mechanisms. In light of all this, it was clear that a different model was required to fit outcome data.

Authors: Olivier Castagna, Cedric Bergmann, Jean Eric Blatteau. Prolonged exposure to a high partial pressure of oxygen leads to inflammation of pulmonary tissue and pulmonary oxygen toxicity (POT), which is associated with tracheobronchial irritation, retrosternal pain, and coughing, and decreases in vital capacity (VC). The nitric oxide (NO) concentration in exhaled gas (FeNO) has been used as an indicator of POT, but the effect of diving on FeNO has rarely been studied. This study assessed alterations to pulmonary function and FeNO following a 12-h dive using breathing apparatus with a relatively high partial pressure of oxygen.

08 - Acute Anxiety Predicts Components of the Cold Shock Response on Cold Water Immersion: Toward an Integrated Psychophysiological Model of Acute Cold Water Survival

Authors: Martin J. Barwood, Jo Corbett, Heather Massey, Terry McMorris, Mike Tipton, and Christopher R. D. Wagstaff Drowning is a leading cause of accidental death. In cold- water, sudden skin cooling triggers the life-threatening cold shock response (CSR). The CSR comprises tachycardia, peripheral vasoconstriction, hypertension, inspiratory gasp, and hyperventilation with the hyperventilatory component inducing hypocapnia and increasing risk of aspirating water to the lungs.

09 - Nitrogen narcosis induced by repetitive hyperbaric nitrogen oxygen mixture exposure impairs long-term cognitive function in newborn mice.

Authors: Bin Peng, Shun-Hua Peng, Run-Ming Qu, Li-Hua Xu, Zheng-Lin Jiang Human beings are exposed to compressed air or a nitrogen-oxygen mixture, they will produce signs and symptoms of nitrogen narcosis such as amnesia or even loss of memory, which may disappear once back to the normobaric environment. This study was designed to investigate the effect of nitrogen narcosis induced by repetitive hyperbaric nitrogen-oxygen mixture exposure on long-term cognitive function in newborn mice and the underlying mechanisms.

Authors: Carelli M, Laurino M, Zaccaro A, Lai E, Passera M, Gemignani A Nitrogen Narcosis is a reversible syndrome affecting divers performing deep dives breathing air. Symptoms go from euphoria, slow reasoning and reaction time, impaired motor coordination, to complete loss of consciousness. Symptoms severity increases as the nitrogen partial pressure increases, with depth. This document is a 1 page PDF designed to be displayed on a large screen

Authors: Pierre Lafère, Peter Germonpré, François Guerrero, Alessandro Marroni, Costantino Balestra Because a significant association between training to perform emergency free ascent (EFA) and the occurrence of pulmonary barotrauma (PBT) was demonstrated in 2006, the Belgian Underwater Federation (BUF) decided to discontinue this procedure. An evaluation was needed 10 yr after the implementation of this change.

Authors: Çigdem Özer Gökaslan, Ugur Toprak, Serkan Gokaslan High-pressure water injuries are usually seen in the extremities and less often in the thorax and abdominal areas. A literature review reveals a few case reports describing intra-abdominal injuries due to penetrating trauma. This paper presents the radiological findings of a rare case of abdominal wall injury without penetration of the peritoneum caused by a high-pressure water jet due to the Coanda effect. The Coanda effect is the tendency of a fluid jet to stay attached to a curve.

Authors: Monika Patel, Arun Dehadaray Acute otitis externa (AOE) is the inflammation of the external ear. It usually presents with severe pain in the ear. The treatment of AOE should aim in relieving pain at the earliest. Out of the various treatment options, topical treatment should be considered as prescribing oral antibiotics without local treatment can cause antibiotic abuse. Due to unavailability, cost, and compliance issues of other topical measures, The authors observed and proved the effectiveness of a new modality glycerine and povidone-iodine wick in the treatment of AOE.

Authors: Shrestha K, Shah R, Sapkota S Otitis externa is a common painful condition presents with generalized infection of external auditory canal, typically reveals erythema and edema of the skin. Aural packing plays an important role in relieving the pain and edema. For packing either we impregnated with 10% Ichthammol glycerine or steroid-antibiotic ointment.

Authors: Piotr Siermontowski, Wojciech Kozłowski, Katarzyna Pleskacz The study aimed to assess the influence of post- pulmonary barotrauma lesions on the heart muscle and the importance of hyperbaric treatment on exacerbating such lesions in the heart. The hearts of 35 rabbits were used in the study. In animals of the experimental group, pulmonary barotrauma was induced in the pressure chamber using the proprietary method described in previous publications.

Authors: M Hobbs & W. Kneller Previous research has demonstrated that nitrogen narcosis causes decrements in memory performance, but the precise aspect of memory impairment is not clear in the literature. Objective: The present research investigated the effect of narcosis on free recall and recognition memory by applying signal detection theory (SDT) to the analysis of the recognition data.

Authors: Gerardo Bosco, Alex Rizzato, Richard E. Moon, and Enrico M. Camporesi This paper illustrates the physiological changes induced by immersion, swimming, breath-hold diving and exploring while using special equipment in the water.

Authors: Brandon W. Lewis, Sonika Patial , and Yogesh Saini The primary purpose of pulmonary ventilation is to supply oxygen for sustained aerobic respiration in multicellular organisms. However, abiotic insults and airborne pathogens present in the environment are occasionally introduced into the airspaces during inhalation, which could be detrimental to the structural integrity and functioning of the respiratory system.Defective mucociliary clearance (MCC) is often associated with airway mucoobstruction, increased occurrence of respiratory infections, and progressive decrease in lung function in mucoobstructive lung diseases.

59 - Gas micronuclei that underlie decompression bubbles and decompression sickness have most probably been identified – in response to the Letter to the editor from Dr David Doolette

Author: Ran Arieli This paper is a response from Doctor Ran Arieli regarding a critic expresse by David Doolette (US Navy) regarding his assertion that nanobubbles formed on a hydrophobic surface are the source of decompression bubbles.

Authors: Giuseppe Accurso, Andrea Cortegiani, Sabrina Caruso, Oriana Danile, Domenico Garbo, Pasquale iozzo, Filippo Vitale, Santi Maurizio Raineri, Cesare Gregoretti, & Antonino Giarratano The authors report two episodes of Taravana syndrome occurred in the same young male spearﬁshing champion affected by hyperho-mocysteinemia treated with recompression treatment at the Hyperbaric Oxygen Therapy (HBOT) Department of the University Hospital Policlinico Paolo Giaccone, Palermo, Italy, in November 2010 and July 2016.

Authors: Q. Buzzacott, D. Schiller, J. Crain, and P. Denoble This study, published in 2018, investigated morbidity and mortality suffered by divers in the US and Canada.

Author: Ran Arieli Taravana is a neurological form of decompression illness (DCI) prevalent in repeated breath-hold diving. A nanobubble on an active hydrophobic spots (AHS) in a distal artery of the brain may receive an influx of nitrogen after each dive until it occludes the arterial blood flow. The vestibular organ has very low perfusion compared with the brain and the cochlea of the inner ear. The author suggests that a nanobbubble on an AHS in the distal artery of the vestibular organ will receive a high influx of nitrogen from the surrounding tissue after decompression due to the low nitrogen clearance, thus expanding to cause vestibular DCI.

Author: Alice Bliznyuk, Hava Golan, & Yoram Grossman Divers that are exposed to high pressure (HP) above 1.1 MPa suffer from High Pressure Neurological Syndrome (HPNS), which is implicated with central nervous system (CNS) malfunction. Marine mammals performing extended and deep breath-hold dives are exposed to almost 20 MPa without apparent HPNS symptoms. N-methyl-D-aspartate receptor (NMDAR) has repeatedly been implicated as one of the major factors in CNS hyperexcitability as part of HPNS. Electrophysiological studies in rat brain slices at He HP showed a significant increase in the synaptic NMDAR response, followed by postsynaptic excitability changes.

Authors: Ashish Tawar, P. Gokulakrishnan This review article is of interest to the doctors who face the dilemma of treating the rare syndrome of DCI that could present in the clinical spectrum ranging from itching and minor pain to severe neurological symptoms or other systemic pathology. The first aid lies in the administration of 100% oxygen, and definitive treatment is therapeutic recompression. With appropriate and adequate treatment, recovery is complete, but some severe cases may have lifelong residual deficits, even after extended and multiple recompressions.

Authors: Erik Hoencamp, Thijs TCF van Dongen , Pieter-Jan AM van Ooij , Thijs T Wingelaar, Mees L Vervelde, Dave AA Koch, Rob A van Hulst, Rigo Hoencamp This paper was a systematic review of human and animal studies of medications in the hyperbaric environment. Studies were subdivided into those describing a medication/hyperbaric environment interaction and those concerned with prevention of diving disorders. Studies without a relation to diving with compressed air, and those concerning oxygen toxicity, hyperbaric oxygen therapy or the treatment of decompression sickness were excluded.

43 - The effect of high pressure on the NMDA receptor: molecular dynamics simulations

Authors: Alice Bliznyuk , Yoram Grossman, & Yevgeny Moskovitz Divers exposed to pressures above 11 bar develop the high pressure neurological syndrome (HPNS), manifesting as central nervous system (CNS) hyperexcitability, motor disturbances, sensory impairment, and cognitive deficits. The glutamate-type N-methyl-D-aspartate receptor (NMDAR) has been implicated in the CNS hyperexcitability of HPNS. NMDARs containing different subunits exhibited varying degrees of increased and decreased current at high pressure. The mechanisms underlying this phenomenon remain unclear.

Authors: Alice Bliznyuk, Hava Golan, & Yoram Grossman Professional divers who are exposed to high pressure (HP) above 1.1 MPa suffer from high pressure neurological syndrome (HPNS), which is characterized by reversible CNS hyperexcitability and cognitive and motor deficits. HPNS remains the final major constraints on deep diving at HP. Prolonged and repetitive exposure to HP during deep sea saturation dives may result in permanent memory and motor impairment. Previous studies revealed that CNS hyperexcitability associated with HPNS is largely induced by N-methyl-D-aspartate receptors (NMDARs). NMDARs that contain the GluN2A subunit are the only ones that show a large current increase at He HP.

52 - Evaluation of Divers’ Neuropsychometric Effectiveness and High -Pressure Neurological Syndrome via Computerized Test Battery Package and Questionnaires in Operational Setting

Author: Simin Berenji Ardestani, Costantino Balestra, Elena V. Bouzinova, Øyvind Loennechen, & Michael Pedersen Symptoms of high-pressure neurological syndrome (HPNS) might appear at depths deeper than 150 meter sea water (msw),due to rapid increase in pressure on the central nervous system during compression. The aim of this study was to first operate a new computerized tool, designed to monitor divers’ wellbeing and cognitive function, and to record the results. The second aim was to evaluate the feasibility and validity of the Physiopad software and HPNS questionnaires as a new tool for monitoring divers wellbeing in an operational setting, including visualization and presentation of results.

Authors: Dirk Mayer, Katja Bettina Ferenz The question of deep and shallow decompression stops is interesting and fraught with controversy in diving circles and operations, training, exploration and scientific endeavors. Plus, fraught with some misunderstanding which is understandable as the issues are complex. We accordingly detail a short history of deep and shallow stops, physical aspects, staging differences, diving tests, models, data correlations, data banks, diver statistics and DCS outcomes for diving amplification. Pros and cons of deep stop and shallow stop staging are presented. Misinformation is corrected. Training Agency Standards regarding deep and shallow stops are included.

Authors: B. R. Wienke, and T. R. O’ Leary The question of deep and shallow decompression stops is interesting and fraught with controversy in diving circles and operations, training, exploration and scientific endeavors. Plus, fraught with some misunderstanding which is understandable as the issues are complex. We accordingly detail a short history of deep and shallow stops, physical aspects, staging differences, diving tests, models, data correlations, data banks, diver statistics and DCS outcomes for diving amplification. Pros and cons of deep stop and shallow stop staging are presented. Misinformation is corrected. Training Agency Standards regarding deep and shallow stops are included.