scientific-2021-part-b

Scientific papers 2021 - Part B

Authors: Costantino Balestra, François Guerrero, Sigrid Theunissen, Peter Germonpré, & Pierre Lafère Purpose: Data regarding decompression stress after deep closed-circuit rebreather (CCR) dives are scarce. This study aimed to monitor technical divers during a wreck diving expedition and provide an insight into venous gas emboli (VGE) dynamics. Methods: Diving practices of ten technical divers were observed. They performed a series of three consecutive daily dives around 100 m. VGE counts were measured 30 and 60 min after surfacing by both cardiac echography and subclavian Doppler graded according to categorical scores (Eftedal–Brubakk and Spencer scale, respectively) that were converted to a simplified bubble grading system (BGS) for the purpose of analysis. Total body weight and fluids shift using bioimpedancemetry were also collected pre and post-dive.

Authors: Robert P. Weenink, & Thijs T. Wingelaar. Increased hydrostatic pressure as experienced during immersion and submersion has effects on the circulation. The main effect is counteracting gravity by buoyancy, which results in reduced extravasation of fluid. Immersion in a cold liquid leads to peripheral vasoconstriction, which centralizes the circulation. Additionally, a pressure difference usually exists between the lungs and the rest of the body, promoting pulmonary edema. However, hydrostatic pressure does not exert an external compressing force that counteracts extravasation, since the increased pressure is transmitted equally throughout all tissues immersed at the same level. Moreover, the vertical gradient of hydrostatic pressure down an immersed body part does not act as a resistance to blood flow. The occurrence of cardiovascular collapse when an immersed person is rescued from the water is not explained by the removal of the hydrostatic squeeze, but by sudden reinstitution of the effect of gravity in a cold and vasoplegic subject.

Authors: Pierre Lafère, Kate Lambrechts, Peter Germonpré, Ambre Balestra, Faye Lisa Germonpré, Danilo Cialoni, Alessandro Marroni, Gerardo Bosco, & Costantino Balestra. Heart rate variability (HRV) during underwater diving has been infrequently investigated because of environmental limitations and technical challenges. This study aims to analyze HRV changes while diving at variable hyperoxia when using an open circuit (OC) air diving apparatus or at constant hyperoxia using a closed-circuit rebreather (CCR). We used HRV analysis in the time and frequency domain adding nonlinear analysis which is more adapted to short- time analysis and less dependent on respiratory rate (Sinus respiratory arrhythmia).

Authors: Alexander Patrician, Frank Pernett, Angelica Lodin- Sundström, Erika Schagatay. Breath-hold diving (freediving) is an underwater sport that is associated with elevated hydrostatic pressure, which has a compressive effect on the lungs that can lead to the development of pulmonary edema. Pulmonary edema reduces oxygen uptake and thereby the recovery from the hypoxia developed during freediving, and increases the risk of hypoxic syncope. The authors aimed to examine the blood oxygenation via pulse-oximetry (SpO2), as a tool to detect pulmonary edema by comparing it to lung ultrasonography measurements after deep diving.

19 - Assessment of Alertness and Cognitive Performance of Closed Circuit Rebreather Divers With the Critical Flicker Fusion Frequency Test in Arctic Diving Conditions

Authors: Wilhelm W. Piispanen, Richard V. Lundell, Laura J. Tuominen, Anne K. Räisänen-Sokolowski. Cold water imposes many risks on the diver. These risks include decompression illness, physical and cognitive impairment, and hypothermia. Cognitive impairment can be estimated using a critical flicker fusion frequency (CFFF) test, but this method has only been used in a few studies conducted in an open water environment. The authors studied the effect of the cold and a helium- containing mixed breathing gas on the cognition of closed-circuit rebreather (CCR) divers.

Authors: Roxane Monnoyer, Ingrid Eftedal, Astrid Hjelde, Sanjoy Deb, Kjersti Haugum, & Jacky Lautridou. The extreme environment in saturation diving affects all life forms, including the bacteria that reside on human skin and mucosa. The oral cavity alone is home to hundreds of different bacteria. In this study, the authors examined the metabolic activity of oral bacteria from healthy males during commercial heliox saturation diving. They focused on environmentally induced changes that might affect the divers’ health and fitness.

Authors: Kiyotaka Kohshi, Petar J. Denoble, Hideki Tamaki, Yoshitaka Morimatsu, Tatsuya Ishitake, and Frédéric Lemaître Nitrogen (N 2 ) accumulation in the blood and tissues can occur due to breath-hold (BH) diving. Post-dive venous gas emboli have been documented in commercial BH divers (Ama) after repetitive dives with short surface intervals. Hence, BH diving can theoretically cause decompression illness (DCI). “Taravana,” the diving syndrome described in Polynesian pearl divers by Cross in the 1960s, is likely DCI. It manifests mainly with cerebral involvements, especially stroke-like brain attacks with the spinal cord spared. Neuroradiological studies on Ama divers showed symptomatic and asymptomatic ischemic lesions in the cerebral cortex, subcortex, basal ganglia, brainstem, and cerebellum. These lesions localized in the external watershed areas and deep perforating arteries are compatible with cerebral arterial gas embolism.

Authors: Xiao-Chen Bao, Quan Shen, Yi-Qun Fang, Jian-guo Wu The objective of this study was to explore whether a single deep helium-oxygen (heliox) dive affects physiological function. Forty male divers performed an open-water heliox dive to 80 m of seawater (msw). The total diving time was 280 min and the breathing helium-oxygen time was 20 min. Before and after the dive, blood and saliva samples were collected, and blood cell counts, cardiac damage, oxidative stress, vascular endothelial activation, and hormonal biomarkers were assayed.

24 - Increased Risk of Decompression Sickness When Diving With a Right-to-Left Shunt: Results of a Prospective Single-Blinded Observational Study (The “Carotid Doppler” Study).

Authors: Peter Germonpré, Pierre Lafère, William Portier, Faye-Lisa Germonpré, Alessandro Marroni, and Costantino Balestra. Divers with a Patent Foramen Ovale (PFO) have an increased risk for decompression sickness (DCS) when diving with compressed breathing gas. The relative risk increase, however, is difficult to establish as the PFO status of divers is usually only determined after a DCS occurrence.

Authors: Svein E. Gaustad, Timofei V. Kondratiev, Ingrid Eftedal, Torkjel Tveita. Diving in cold water is thought to increase the risk of decompression sickness (DCS), especially if the diver is cold during decompression. In this study, the authors investigated hemodynamic function and DCS risk in an animal model, where cold decompression was followed by rewarming at the surface.

Authors: Peter Kyriakoulis, Michael Kyrios, Antonio Egidio Nardi, Rafael C. Freire, & Mark Schier. Increased CO2 sensitivity is common in panic disorder (PD) patients. Free-divers who are known for their exceptional breathing control have lower CO2 sensitivity due to training effects. This study aimed to investigate the immediate effects of cold facial immersion (CFI), breath- holding, and CO2 challenges on panic symptoms.

Authors: Thomas Kjeld, Anders Brenøe Isbrand, Katrine Linnet, Bo Zerahn, Jens Højberg, Egon Godthaab Hansen, Lars Christian Gormsen, Jacob Bejder, Thomas Krag, John Vissing, Hans Erik Bøtker, and Henrik Christian Arendrup. The cardiac electrical conduction system is very sensitive to hypoglycemia and hypoxia, and the consequence may be brady-arrythmias. Weddellseals endure brady-arrythmias during their dives when desaturating to 3.2 kPa and elite breath-hold-divers (BHD), who share metabolic and cardiovascular adaptions, including bradycardia with diving mammals, endure similar desaturation during maximum apnea. The authors hypothesized that hypoxia causes brady- arrythmias during maximum apnea in elite BHD. Hence, this study aimed to define the arterial blood glucose (Glu), peripheral saturation (SAT), heart rhythm (HR), and mean arterial blood pressure (MAP) of elite BHD during maximum apneas.

Authors: Kil-Hyung Han, Gwang-Suk Hyun, Yong-Seok Jee, & Jung- Min Park This study aimed to investigate the influence of pre- hydration levels on circulating bubble formation for scuba divers and evaluate the appropriate volume of water intake before diving for reducing the risk of decompression sickness. Circulating bubble measurements using doppler were performed before and after a dive of 25 min and a depth of 30 m on twenty scuba divers who were classified into four groups: no-water-intake, 30%- water-intake, 50%-water intake, and 100%-water-intake.

Author: Ran Arieli This study suggests nanobubbles, which appear at the active hydrophobic spots at the luminal aspect of the blood vessels, are the gas micronuclei from which the decompression bubbles evolve, and endothelial injury during the decompression is due to the tearing off of the cell membranes with the detaching bubbles.

Authors: Robin Pla, Gauthier Poszalczyk, Cyrine Souaissia, Fabrice Joulia, and Alexandre Guimard This paper introduces an improving method that can estimate the size of microbubbles in real time. Hence, the measurement data of the liquid volume can be modified according to this method. A microbubble detector based on the pulsed-ultrasound method was studied, including the device structure and the working principle.

Author: Yiqing Li, Junwu Wu, Leijie Fu, and Jinju Wang Although the role of underwater phases is well-known, no study has taken an interest in describing and quantifying the distance and time spent in apnea as a condition for optimal performance. This study aimed to investigate the impact of time and distance spent underwater and surface parameters on the swimming performance of elite swimmers. The performances of 79 swimmers in 100-m freestyle were analyzed (short-course).

01 - European position paper on the management of patients with patent foramen ovale. Part II - Decompression sickness, migraine, arterial deoxygenation syndromes and select high-risk clinical conditions.

Authors: Christian Pristipino, Peter Germonpré, Danilo Toni, Horst Sievert, Bernhard Meier, Fabrizio D’Ascenzo, Sergio Berti, Eustaquio Maria Onorato, Francesco Bedogni, Jean-Louis Mas, Paolo Scacciatella, David Hildick-Smith, Fiorenzo Gaita, Paul A. Kyrle, John Thomson, Genevieve Derumeaux, Dirk Sibbing, Massimo Chessa, Marius Hornung, Jose Zamorano, Dariusz Dudek This interdisciplinary paper, prepared with the involvement of eight European scientific societies, reviews the available evidence and proposes a rationale for decision making for other Patent Foramen Ovale related clinical conditions.

Authors: Danilo Cialoni, Andrea Brizzolari, Michele Samaja, Gerardo Bosco, Matteo Paganini, Nicola Sponsiello, Valentina Lancellotti, and Alessandro Marron. Nitric oxide (NO) is an essential signaling molecule modulating the endothelial adaptation during breath-hold diving (BH-diving). This study aimed to investigate changes in NO derivatives (NOx) and total antioxidant capacity (TAC), searching for correlations with different environmental and hyperbaric exposure.

Authors: Shumaila Mumtaz, Shaukat Ali, Hafiz Muhammad Tahir, Syed Akif Raza Kazmi, Hafiz Abdullah Shakir, Tafail Akbar Mughal, Samaira Mumtaz, Muhammad Summer, Muhammad Adeel Farooq This purely medical document has been selected because it discusses using vitamin C as an antioxidant to combat oxidative stress triggered by reactive oxygen species. As explained in our handbooks, reactive oxygen species are necessary for life. However, they can be involved in cell destruction when produced in excess, which happens when the body is confronted with abnormal situations, such as breathing oxygen at elevated Partial pressure.

28 - Mechanisms of Hypoxia-Induced Pulmonary Arterial Stiffening in Mice Revealed by a Functional Genetics Assay of Structural, Functional, and Transcriptomic Data

Authors: Edward P. Manning, Abhay B. Ramachandra, Jonas C. Schupp, Cristina Cavinato, Micha Sam Brickman Raredon, Thomas Bärnthaler , Carlos Cosme Jr., Inderjit Singh, George Tellides, Naftali Kaminski, and Jay D. Humphrey Hypoxia adversely affects the pulmonary circulation of mammals, including vasoconstriction leading to elevated pulmonary arterial pressures. The authors established a multi-disciplinary workflow to understand better transcriptional, microstructural, and functional changes of the pulmonary artery in response to sustained hypoxia and how these changes inter-relate.

Author: Rutger C Lalieu, Ida Akkerman, Peter-Jan AM van Ooij, Annieke A Boersma-Voogd, Rob A van Huls Due to the global rise of obesity, the role of nutrition has gathered more attention. Paradoxically, even overweight persons may be malnourished. This may delay wound healing or recovery of late radiation tissue injury (LRTI). Hyperbaric oxygen treatment (HBOT) is used to improve wound healing or LRTI complaints. The aim of this study was to assess the dietary intake levels of nutrients important for recovery in patients referred for HBOT.

Author: Yan Tian, Yafang Zhang, Yu Wang, Yunxi Chen, Weiping Fan, Jianjun Zhou, Jing Qiao, and Youzhen Wei Molecular hydrogen (H2) is a colorless and odorless gas. Studies have shown that H2 inhalation has therapeutic effects in many animal studies and clinical trials. Its application has recently been recommended in China's novel coronavirus pneumonia treatment guidelines. H2 is primarily administered via inhalation, drinking H2-rich water, or injection of H2 saline. It may participate in the anti-inflammatory and antioxidant activity and immune system regulation by annihilating excess reactive oxygen species production and modulating nuclear transcription factors.

Authors: Karin Biering, Anette Kærgaard, Ole Carstensen, Kent Jacob Nielsen. This study aimed to monitor exposure to electrical shocks weekly over six months and to determine whether these shocks have short-term, health-related consequences. Its results should be considered for the safety of surface technicians involved in the maintenance of Diving and ROV systems.

Authors: Tobias Cibis & Carolyn McGregor This book overviews the technical and clinical challenges of living and working in extreme environments. It blends the story of physiological and psychological adaptation to harsh environments on Earth and the two final frontiers of space and the undersea world. It also discusses new technologies and the role of artificial intelligence in helping monitor and detect physiologic decompensation, illness, or injury.

Authors: Oskari H Lindfors, Anne K Räisänen-Sokolowski, Jari Suvilehto, Saku T Sinkkonen Sinus barotrauma while diving is considered to be the consequence of insufficient paranasal sinus ventilation during ambient pressure changes, when either ascending or descending on a dive, or when diving in a multilevel environment. The sinuses most often affected are considered to be the frontal and maxillary sinuses, while involvement of the sphenoid and ethmoid sinuses is thought to be less common.

Authors: Barbara Nieradko-Iwanicka, Daria Przybylska, Piotr Siermontowski, Cezary J. Kowalski, Marta Wójciak-Czuła, Andrzej Borzecki Hyperbaric oxygen therapy is a method supporting the treatment of many diseases. Oxygen therapy treatments are conducted in hyperbaric chambers, in which patients breathe pure, 100% oxygen with higher than atmospheric pressure. This allows to increase the amount of oxygen supplied to all cells of the body many times over. The treatment with hyperbaric oxygen therapy enables the patient to recover faster and be fully active, and also reduces the costs of standard treatment.

Authors: Alessandro Belletti, Giovanni Landoni, Alberto Zangrillo In their multicenter study, the Authors present incidence, clinical characteristics and outcome of pneumothorax in critically ill patients with coronavirus disease 2019 (COVID-19). They found that pneumothorax rate among invasively ventilated COVID-19 patients is 80/594 (13 %), and mortality rate for patients who developed pneumothorax is 50/80 (62 %). On the contrary, among 160 randomly selected invasively ventilated COVID-19 patients without pneumothorax, mortality was 78/160 (49 %).

Authors: Wen-Jie Wang, Jia-Sheng Ding, Qing Sun, Xiang Xu, Gang Chend Gliomas are common brain masses with a high mortality rate. Patients with gliomas have a severely poor outcome, with an average survival duration of less than 15 months due to high recurrence rates and resistance to radiotherapy and chemistry drugs therapy. Hyperbaric oxygen is extensively used as an adjuvant treatment for various disease conditions. The authors found that, in general, hyperbaric oxygen shows an obvious positive effect on the treatment of gliomas, and it can also relieve the complications caused by postoperative radiotherapy and chemotherapy of gliomas.

Authors: Selahattin Çakiroglu, Ertugrul Kerimoglu, Bengüsu Mirasoglu Dysbaric osteonecrosis (DON) is a type of avascular bone necrosis observed in divers and pressure environmental employees. Early diagnosis is particularly crucial in DON. The lesions can be detected through bone scintigraphy, magnetic resonance imaging (MRI), or direct radiography. Hyperbaric oxygen therapy has been successfully used to treat avascular necrosis in the early stages of avascular necrosis. Early results of hyperbaric oxygen therapy (HBOT) showed positive outcomes in the treatment of DON.

Authors: Micaela Tobler, Christos T. Nakas, Matthias P. Hilty, Andreas Huber, Tobias M. Merz, and Jacqueline Pichler Hefti Changes in blood coagulation during exposure to high altitude is not fully understood. Also, studies on the activation and consumption of specific coagulation factors in hypoxic humans have yielded conflicting results. The authors used thromboelastometry (TEM), which allows for a global evaluation of clot formation and lysis processes, to study blood coagulation profiles in volunteers exposed to prolonged hypobaric hypoxia at extreme altitudes..

Author: Hussam Haider Salman, Adnan khudhier yaqoop, Rafid Y. Jabbar Almaidi Tympanometry is an objective test that measures the mobility (compliance) of the tympanic membrane as a function of applied air pressure in the external canal. It is particularly useful in assessing the secretory otitis media during childhood. This is a prospective study performed at the ENT department of the Basrah Teaching Hospital for the period from November / 2013 to February / 2014. The study aims to assess the advantages of tympanometry as a diagnostic tool and to audit the use of tympanometry in ear diseases in the ENT department of the Basrah Teaching Hospital.

Authors: Andreas Fichtner, Benedikt P. Brunner, Thomas Pohl, Thomas Grab, Tobias Fieback, Thea Koch The authors taught audio Doppler self-assessment of subclavian and precordial probe positions to 41 divers in a 45-minute standardized, didactically optimized training session. In conclusion, the authors suggest that although accurate bubble grading is not possible under dive site conditions, non-professionals can detect relevant high bubble grades. This qualitative information may be important for self-assessment of decompression stress and for evaluating measures to increase diving safety.

Authors: Pierre Lafère, Kate Lambrechts, Peter Germonpré, Ambre Balestra, Faye Lisa Germonpré, Danilo Cialoni, Alessandro Marroni, Gerardo Bosco, & Costantino Balestra. Heart rate variability (HRV) during underwater diving has been infrequently investigated because of environmental limitations and technical challenges. This study aims to analyze HRV changes while diving at variable hyperoxia when using an open circuit (OC) air diving apparatus or at constant hyperoxia using a closed-circuit rebreather (CCR). We used HRV analysis in the time and frequency domain adding nonlinear analysis which is more adapted to short- time analysis and less dependent on respiratory rate (Sinus respiratory arrhythmia).

Authors: Rickard Ånell, Mikael Grönkvist, Mikael Gennser, Ola Eiken This study investigated whether an early excursion from high to moderate altitude can reduce high-altitude decompression strain. The conclusion is that an early, single excursion from high to moderate cabin altitude holds promise as an in-flight means of reducing the risk of altitude decompression sickness during long-duration high-altitude flying in aircraft with limited cabin pressurization. This document should be considered for travel by non- pressurized aircraft after diving.

Authors: Chao Tan, Yuichi Murai, Weiling Liu, Yuji Tasaka, Feng Dong , Yasushi Takeda Ultrasound Doppler measures multiphase flow velocities non-intrusively, aiding in fluid dynamics analysis, industrial safety, and process optimization. This review discusses its principles, developments, and the measurement of various flow types, highlighting the technique's benefits, limitations, and future directions.

Author: Roxane Monnoyer, Jacky Lautridou, Sanjoy Deb, Astrid Hjelde, and Ingrid Eftedal The authors investigated whether measuring salivary biomarkers in samples collected by the divers themselves would be a feasible approach for assessing environmental stress. Nine saturation divers were trained in saliva collection methods and collected samples before, during, and after an offshore commercial saturation diving campaign. During the dive, some salivary biomarkers were found to increase significantly, while others remained unchanged. This suggests that this method is suitable for assessing stress levels during saturation diving.

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Authors: Kay Tetzlaff, Frederic , Christof Burgstahler, Julian A. Luetkens, & Lars Eichhorn This study explains the environmental stressors, such as water immersion, hydrostatic pressure, and asphyxia, that affect the respiratory system during such dives. It discusses the physiological adaptations and techniques used by elite breath-hold divers to achieve extreme depths, as well as the potential medical risks, including nitrogen narcosis and decompression stress, associated with deep breath-hold diving. Also, it highlights that the ultimate goal is to enhance understanding of pulmonary physiology at depth and to assess the medical risks involved.

Authors: Miguel A. Ortega, Oscar Fraile-Martinez, Cielo García-Montero, Enrique Callejón-Peláez, Miguel A. Sáez, Miguel A. Álvarez-Mon, Natalio García- Honduvilla, Jorge Monserrat, Melchor Álvarez- Mon, Julia Bujan, and María Luisa Canals This paper is a comprehensive review of Hyperbaric Oxygen Therapy (HBOT) that discusses its physiological relevance and therapeutic basis, including its current indications, underlying mechanisms, and potential areas for future research. It also intends to examine the adverse effects and contraindications associated with HBOT and encourage further research to expand its clinical applications.

Authors: Fichtner A, Chekhanova A, Wuensche A, Starkloff HJ, Fieback T, Koch T. This study investigates the relationship between dive profiles, individual parameters, and fluid loss in SCUBA divers. It develops an estimation of the necessary amount of fluid restoration between dives to reduce the risk of decompression sickness, in addition to outlining the methods used, the results obtained, and the discussion of the findings, emphasizing the importance of sufficient hydration for divers and the challenges in quantifying fluid loss mechanisms.

Author: Omar M. Abdelfattah, Ahmed Sayed, Islam Y. Elgendy, Malak Munir, , Yehia Saleh, Samir R. Kapadia, George S. Abela, Hani Jneid This study evaluates the benefits and risks of patent foramen ovale (PFO) closure in preventing decompression sickness among divers. It determines whether PFO closure reduces the incidence of decompression sickness and assesses the associated adverse events. The authors provide a detailed methodology, results, and conclusion based on the analysis of observational studies.