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Nitrogen narcosis

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 be disappeared 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. The electroencephalogram frequency was decreased while the amplitude was increased in a pressure-dependent manner during 0...
2018: PloS One
Fabian Steinberg, Michael Doppelmayr
Moving and acting underwater within recreational or occupational activities require intact executive functions, since they subserve higher cognitive functions such as successful self-regulation, coping with novel situations, and decision making; all of which could be influenced by nitrogen narcosis due to elevated partial pressure under water. However, specific executive functions that could provide a differentiated view on humans' cognitive performance ability have not yet been systematically analyzed in full-water immersion, which is a research gap addressed within this approach to contribute to a better understanding of nitrogen narcosis...
2017: Frontiers in Psychology
Patrick Magee
Artificial breathing systems to help humans survive extreme environments are used over a range of ambient pressures, using various gases of different volumetric concentrations. These activities include anaesthesia and intensive care activity, high-altitude mountaineering, firefighting, aerospace extravehicular space activity and underwater diving operations. A circle breathing system is one in which the exhaled carbon dioxide is absorbed by an alkali substance and the remaining unused gases are recirculated, usually for the sake of economy and environment...
July 2017: Proceedings of the Institution of Mechanical Engineers. Part H, Journal of Engineering in Medicine
Anne-Kathrin Brebeck, Andreas Deussen, Henning Schmitz-Peiffer, Ursula Range, Costantino Balestra, Sinclair Cleveland, Jochen D Schipke
Backround: Nitrogen narcosis impairs cognitive function, a fact relevant during SCUBA-diving. Oxygen-enriched air (nitrox) became popular in recreational diving, while evidence of its advantages over air is limited. AIM: Compare effects of nitrox28 and air on two psychometric tests. METHODS: In this prospective, double-blind, open-water study, 108 advanced divers (38 females) were randomized to an air or a nitrox-group for a 60-min dive to 24 m salt water. Breathing gas effects on cognitive performance were assessed during the dive using a short- and long-term memory test and a number connection test...
July 2017: Research in Sports Medicine
Thierry Krummel, Alicia Thiery, Marion Villain, Bernard Schittly, Benoit Brouant
Recreational scuba diving is no longer reserved for young healthy individuals, and as a result, medical drug consumption is on the rise in the diving population. Due to the possible potentiation of nitrogen narcosis by psychotropic drugs, the latter are hence discouraged and are subject to contraindications for practice. However, there are no available experimental data to support this theoretical assumption. The objective of this study is to investigate whether psychotropic drug users are more at risk of severe narcosis...
April 2017: International Journal of Sports Medicine
Geoffrey E Ciarlone, Jay B Dean
Central CO2 chemoreceptive neurons in the caudal solitary complex (cSC) are stimulated by hyperoxia via a free radical mechanism. Hyperoxia has been shown to increase superoxide and nitric oxide in the cSC, but it remains unknown how changes in Pco2 during hyperoxia affect the production of O2-dependent reactive oxygen and nitrogen species (RONS) downstream that can lead to increased levels of oxidative and nitrosative stress, cellular excitability, and, potentially, dysfunction. We used real-time fluorescence microscopy in rat brain slices to determine how hyperoxia and hypercapnic acidosis (HA) modulate one another in the production of key RONS, as well as colorimetric assays to measure levels of oxidized and nitrated lipids and proteins...
December 1, 2016: American Journal of Physiology. Cell Physiology
Geoffrey E Ciarlone, Jay B Dean
Central CO2-chemosensitive neurons in the caudal solitary complex (cSC) are stimulated not only by hypercapnic acidosis, but by hyperoxia as well. While a cellular mechanism for the CO2 response has yet to be isolated, previous data show that a redox-sensitive mechanism underlies neuronal excitability to hyperoxia. However, it remains unknown how changes in Po2 affect the production of reactive oxygen and nitrogen species (RONS) in the cSC that can lead to increased cellular excitability and, with larger doses, to cellular dysfunction and death...
December 1, 2016: American Journal of Physiology. Cell Physiology
John Jacob Freiberger, Bruce Derrick, Michael J Natoli, Igor Akushevich, Eric A Schinazi, Carl Parker, Bret W Stolp, Peter B Bennett, Richard D Vann, Sophia A S Dunworth, Richard E Moon
INTRODUCTION: Diving narcosis results from the complex interaction of gases, activities and environmental conditions. We hypothesized these interactions could be separated into their component parts. Where previous studies have tested single cognitive tasks sequentially, we varied inspired partial pressures of CO2, N2 and. O2 in immersed, exercising subjects while assessing multi-tasking performance with the MATB-II flight simulator. METHODS: Cognitive performance was tested under 20 conditions of gas partial pressure and exercise in 42 male subjects meeting US Navy age and fitness profiles...
September 15, 2016: Journal of Applied Physiology
Jean-Claude Rostain, Cécile Lavoute
Gases that are not metabolized by the organism are thus chemically inactive under normal conditions. Such gases include the "noble gases" of the Periodic Table as well as hydrogen and nitrogen. At increasing pressure, nitrogen induces narcosis at 4 absolute atmospheres (ATAs) and more in humans and at 11 ATA and more in rats. Electrophysiological and neuropharmacological studies suggest that the striatum is a target of nitrogen narcosis. Glutamate and dopamine release from the striatum in rats are decreased by exposure to nitrogen at a pressure of 31 ATA (75% of the anesthetic threshold)...
June 13, 2016: Comprehensive Physiology
Costantino Balestra, Peter Germonpré
SCUBA diving exposes divers to decompression sickness (DCS). There has been considerable debate whether divers with a Patent Foramen Ovale of the heart have a higher risk of DCS because of the possible right-to-left shunt of venous decompression bubbles into the arterial circulation. Symptomatic neurological DCS has been shown to cause permanent damage to brain and spinal cord tissue; it has been suggested that divers with PFO may be at higher risk of developing subclinical brain lesions because of repeated asymptomatic embolization of decompression-induced nitrogen bubbles...
2016: Frontiers in Psychology
David R Pendergast, Richard E Moon, John J Krasney, Heather E Held, Paola Zamparo
Water covers over 70% of the earth, has varying depths and temperatures and contains much of the earth's resources. Head-out water immersion (HOWI) or submersion at various depths (diving) in water of thermoneutral (TN) temperature elicits profound cardiorespiratory, endocrine, and renal responses. The translocation of blood into the thorax and elevation of plasma volume by autotransfusion of fluid from cells to the vascular compartment lead to increased cardiac stroke volume and output and there is a hyperperfusion of some tissues...
October 2015: Comprehensive Physiology
Yang-yang Li, Lu Shi, Yan-meng Zhang, Chan-juan Xiao, Hong-tao Liu
OBJECTIVE: To explore the underwater decompression schedule for 100 m Trimix conventional diving operations and evaluate its safety through a simulated rabbits Trimix conventional diving. METHODS: According to the Haldane theory, the assumed time units, the classification of tissue compartments, the nitrogen super-saturation safety coefficient and the selection of methods used for the calculation of the simulated 100 m Trimix conventional diving schedule were properly selected, and the calculating method for the dive decompression schedule was thus firmly established...
May 2015: Chinese Journal of Applied Physiology
Yu Wang, Liang Chen, Xiaogang Wang, Chaoqing Dai, Junlang Chen
The lateral pressure exerted on cell membrane is of great importance to signal transduction. Here, we perform molecular dynamics simulation to explore how lateral pressure affects the biophysical properties of lipid bilayer as well as nitrogen distribution in the membrane. Our results show that both physical properties of cell membrane and nitrogen distribution are highly sensitive to the lateral pressure. With the increasing lateral pressure, area per lipid drops and thickness of membrane increases obviously, while nitrogen molecules are more congested in the center of lipid bilayer than those under lower lateral pressure...
May 2015: Journal of Molecular Modeling
James E Clark
Exposure to the underwater environment for pleasure or work poses many challenges on the human body including thermal stress, barotraumas, decompression sickness as well as the acute effects of breathing gases under pressure. With the popularity of recreational self-contained underwater breathing apparatus (SCUBA) diving on the increase and deep inland dive sites becoming more accessible, it is important that we understand the effects of breathing pressurised gas at depth can have on the body. One of the common consequences of hyperbaric gas is the narcotic effect of inert gas...
2015: Extreme Physiology & Medicine
Charles H van Wijk, W A J Meintjes
BACKGROUND: The interaction of subjective experiences and objective measures of neuropsychological performance during hyperbaric exposure has received less attention in the literature, in part due to the shortage of available and appropriately standardized measures. OBJECTIVE: This study aimed to describe the psychometric properties of a modified version of the Subjective High Assessment Scale when used in the hyperbaric context, by exploring internal reliability, factor structure, associations with psychological variables and simple cognitive delayed recall, and the effect of task focus on the recall of subjective experience...
November 2014: Undersea & Hyperbaric Medicine: Journal of the Undersea and Hyperbaric Medical Society, Inc
Charles H van Wijk, W A J Meintjes
OBJECTIVE: Commercial diving often occurs in low visibility, where divers are reliant on their tactile senses. This study examined the effect of nitrogen narcosis on tactile memory for shapes as well as the influence of psychological and biographical factors on this relationship. METHOD: This crossover study tested 139 commercial divers in a dry hyperbaric chamber at 101.325 and 607.95 kPa (1 and 6 atmospheres absolute/atm abs). Divers memorized shapes while blindfolded, using their tactile senses only...
September 2014: Undersea & Hyperbaric Medicine: Journal of the Undersea and Hyperbaric Medical Society, Inc
Jacqueline Conger, Everett F Magann
Exercise during pregnancy has been advocated by many professional organizations to promote fetal heath and maternal well-being. Those same professional organizations do not recommend diving during pregnancy because of the potential adverse outcomes that have been observed in the animal model. In nonpregnant women, diving becomes problematic at depth as the ambient pressure increases and more gases become dissolved in the bloodstream. This can result in oxygen toxicity and nitrogen narcosis. Too rapid an ascent from depth can cause nitrogen emboli that can lodge in joints and tissue, resulting in decompression sickness, known as "the bends...
September 2014: Obstetrical & Gynecological Survey
Charles H van Wijk, Willem A J Meintjes
BACKGROUND: In a task-environment where visibility has deteriorated, individuals rely heavily on tactile performance (perception and manipulation) to complete complex tasks. When this happens under hyperbaric conditions, factors like nitrogen narcosis could influence a person's ability to successfully complete such tasks. OBJECTIVE: To examine the effect of nitrogen narcosis on a complex neuropsychological task measuring tactile performance at a pressure of 608 kPa (6 atm abs), in the absence of visual access to the task...
June 2014: Diving and Hyperbaric Medicine: the Journal of the South Pacific Underwater Medicine Society
Seichi Horie
Exposure to heat disturbs the homeostasis of body water, serum osmosis, and core temperature, resulting in the development of heat cramp, heat syncope, heat exhaustion, and heat stroke. Commonly coexisting risks are humidity, windlessness, infrared radiation, physical exertion, continuous work, chemical protective clothing, and lack of acclimatization. Exposure to cold constricts peripheral arteries and reduces metabolism, resulting in the development of chilblains, frostbite, immersion foot, and hypothermia...
February 2014: Nihon Rinsho. Japanese Journal of Clinical Medicine
Cédric Meckler, Jean-Eric Blatteau, Thierry Hasbroucq, Bruno Schmid, Jean-Jacques Risso, Franck Vidal
Certain underwater circumstances carry risk of inert gas narcosis. Impairment of sensorimotor information processing due to narcosis, induced by normobaric nitrous oxide or high partial nitrogen pressure, has been broadly evidenced, by a lengthening of the reaction time (RT). However, the locus of this effect remains a matter of debate. We examined whether inert gas narcosis affects the response-selection stage of sensorimotor information processing. We compared an air normobaric condition with a hyperbaric condition in which 10 subjects were subjected to 6 absolute atmospheres of 8...
2014: Ergonomics
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