Oxygen toxicity or oxygen toxicity syndrome (also known as the "Paul Bert effect"[1][2][3] or the "Lorrain Smith effect"[1][4]) is severe hyperoxia caused by breathing oxygen at elevated partial pressures. Toxicology (from the Greek words toxicos and logos) is the study of the adverse effects of Chemicals on living organisms Forensic toxicology is the use of Toxicology and other disciplines such as Analytical chemistry, Pharmacology and Clinical chemistry to aid medicolegal Toxinology is the specialized area of Toxicology that deals specifically with animal plant and microbial toxins but is also considered a science in its own right The history of Poison stretches from before 4500 BC to the Present day. S00-T14 - Injury (S00-S09 Head ( Superficial Injury of head ( Superficial injury of 17 Injury and poisoning (800-999 fracture of skull (800-804 ( Fracture of Vault of skull ( Fracture of Base of skull In the context of Biology, poisons are substances that can cause damage, Illness, or Death to Organisms usually by This article is about the class of Biotoxins For other uses see Venom (disambiguation and Venomous (disambiguation. A toxicant is a chemical compound that has an effect on organisms An antidote or counterdose is a substance which can counteract a form of Poisoning. Acceptable daily intake or ADI is a measure of the amount of a specific substance (usually a Food additive, or a residue of a veterinary drug or pesticide in Acute toxicity describes the adverse effects of a substance which result either from a single exposure or from multiple exposures in a short space of time (usually less than 24 hours Bioaccumulation occurs when an organism absorbs a toxic substance at a rate greater than that at ftudruinsubstance is lost Biomagnification, also known as bioamplification, or biological magnification is the increase in concentration of a substance such as the Pesticide Fixed Dose Procedure (FDP proposed in 1984 is a method to assess a substance's acute oral Toxicity. In Toxicology, the median lethal dose, LD50 (abbreviation for “Lethal Dose 50%” or LCt50 (Lethal Concentration & Time of a A lethal dose (LD is an indication of the Lethality of a given substance or type of Radiation. Toxic capacity can mean the Toxicity of a substance possibly in relation to a specific Organism and toxic capacity can mean the capacity of an organism Toxicity Class refers to a classification system for Pesticides created by a national or international government-related or -sponsored organization A toxin ( Greek:, toxikon, lit (poison for use on arrows is a Poisonous substance produced by living cells or organisms that is active at very low This article is about the class of Biotoxins For other uses see Venom (disambiguation and Venomous (disambiguation. A neurotoxin is a Toxin that acts specifically on nerve cells ( Neurons, usually by interacting with Membrane proteins such as Ion channels Necrosis (in Greek Νεκρός = "dead" is the name given to unnatural Death of cells and living tissue. Hemotoxins, haemotoxins or hematotoxins are Toxins that destroy Red blood cells (that is cause Hemolysis) disrupt Blood Mycotoxin (from the Greek μύκης (mykes mukos "fungus" is a Toxin produced by an organism of the Fungus kingdom which includes Mushrooms Aflatoxins are naturally occurring Mycotoxins that are produced by many species of Aspergillus, a Fungus, most notably Aspergillus Phototoxins are Toxins that can cause allergic reactions in particularly susceptible individuals and which can cause dangerous Photosensitivity in a much broader range This is a list of toxins poisons and chemical weapons from works of fiction (usually in Fantasy and Science fiction) The Bradford sweets poisoning was the accidental Arsenic poisoning of more than 200 people in Bradford, England in 1858 an estimated 20 people died when sometimes referred to as, is a neurological syndrome caused by severe Mercury poisoning. is a Neurological syndrome caused by severe Mercury poisoning. Alexander Litvinenko was a former officer of Russian Federal Security Service, who escaped prosecution in Russia and received a Political asylum in The Bhopal disaster was an Industrial disaster that occurred in the city of Bhopal, Madhya Pradesh, India, resulting in the immediate deaths The 2007 pet food recalls comprise the contamination and wide recall of many brands of cat and dog foods beginning in March 2007 and the ensuing developments This is a list of Poisonings in chronological order of victim Toxic metals are Metals that form Poisonous soluble compounds and have no biological role i Lead poisoning (also known as saturnism, plumbism, or painter's colic) is a medical condition caused by increased levels of the metal Lead in Mercury poisoning (also known as mercurialism, hydrargyria, Hunter-Russell syndrome, or acrodynia when affecting children is a Disease Cadmium has no constructive purpose in the Human body It and its compounds are extremely Toxic even in low concentrations and will Bioaccumulate in Antimony (IPA (Received Pronunciation, /ˈæntɪmoʊni/ (US is a Chemical element with the symbol Sb (stibium meaning "mark" and Arsenic Poisoning kills by Allosteric inhibition of essential metabolic Enzymes, leading to death from multi-system Beryllium (bəˈrɪliəm is a Chemical element with the symbol Be and Atomic number 4 Iron poisoning is caused by a large excess of Iron intake It has been primarily been associated with young children who consumed large quantities of iron supplement pills Thallium (ˈθæliəm is a Chemical element with the symbol Tl and Atomic number 81 In high concentrations soluble Fluoride Salts are somewhat Toxic. There are four syndromes called shellfish poisoning, which share some common features and are primarily associated with bivalve molluscs (such as Mussels Paralytic shellfish poisoning (PSP is one of the four recognized syndromes of Shellfish poisoning (the others being Neurotoxic shellfish poisoning, diarrhetic Diarrhetic shellfish poisoning (DSP is one of the four recognised symptom types of Shellfish poisoning, the others being Paralytic shellfish poisoning, Neurotoxic Amnesic shellfish poisoning (ASP is a human illness caused by consumption of the marine biotoxin called Domoic acid. Ciguatera is a Foodborne illness poisoning in humans caused by eating Marine species whose flesh is contaminated with a toxin known as Ciguatoxin, Scombroid food poisoning is a foodborne Illness that results from eating spoiled (decayed Fish. Tetrodotoxin (anhydrotetrodotoxin 4-epitetrodotoxin tetrodonic acid TTX is a potent Neurotoxin with no known antidote which blocks Action potentials in Nerves Pesticide Poisonings occur when chemicals intended to control a pest affect non-target organisms such as Humans Wildlife, or Bees Since Many Organophosphates are potent Neurotoxins functioning by inhibiting the action of Acetylcholinesterase (AChE in nerve cells. Foodborne illness (also foodborne disease) is any Illness resulting from the consumption of food Historically most cases of nicotine poisoning have been the result of its use as an Insecticide; however such use is less frequent now than previously Carbon monoxide poisoning occurs after the inhalation of Carbon monoxide gas Vitamin poisoning, or hypervitaminosis, refers to a condition of high storage levels of Vitamins which can lead to Toxic Symptoms The medical The term drug overdose (or simply overdose or OD) describes the Ingestion or application of a Drug or other substance in quantities See also List of deadly fungi Mushroom poisoning, also known as mycetism, refers to deleterious effects from ingestion of Toxic substances present This is a list of Plants containing Poisonous parts that pose a serious risk of illness, injury or Death to Humans or Animals. Hazard symbols are easily recognizable symbols designed to warn about hazardous materials or locations The term carcinogen refers to any substance Radionuclide or radiation that is an agent directly involved in the promotion of Cancer or in the fatation of its propagation In Biology, a mutagen ( Latin, literally origin of change) is a physical or chemical agent that changes the genetic information (usually DNA) This is a list of Extremely Hazardous Substances as defined by Section 302 of the U Biological warfare (BW — known as a germ warfare, biological weapons and bioweaponry — is the use of any Pathogen ( Bacterium Paul Bert ( October 17, 1833 - November 11, 1886) was a French Physiologist and Politician. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the In a mixture of Ideal gases each gas has a partial pressure which is the pressure which the gas would have if it alone occupied the volume [1][5][6] These above-normal concentrations of oxygen within the body can cause cell damage in two principal regions: the central nervous system (CNS); and the lungs (pulmonary). In Chemistry, concentration is the measure of how much of a given substance there is mixed with another substance The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called In Vertebrates the central nervous system ( CNS) is the part of the Nervous system which is enclosed in the Meninges. lung is the essential Respiration organ in air-breathing Animals including most Tetrapods a few Fish and a few Snails The most primitive [7] Over time, it can also cause damage to the retina and may be implicated in some retinopathic conditions. The vertebrate retina is a light sensitive part inside the inner layer of the Eye. [8][9]
The damage may be caused by long exposure (days) to lower concentrations of oxygen or by shorter exposure (minutes or hours) to high concentrations. Long exposures to partial pressure of oxygen above 0. 5 bar (50 kPa) can result in pulmonary oxygen toxicity and are a concern for patients breathing pure oxygen for extended periods. The bar (symbol bar) decibar (symbol dbar) and the millibar (symbol mbar, also mb are units of Pressure. [10][11][12] Short exposures to partial pressure of oxygen above 1. 6 bar (160 kPa) are usually associated with CNS oxygen toxicity and are most likely to occur among divers[13][14] and those undergoing hyperbaric oxygen therapy. Hyperbaric medicine, also known as hyperbaric oxygen therapy (HBOT is the medical use of Oxygen at a higher than Atmospheric pressure. [15]
Prevention of oxygen toxicity is an important precaution whenever oxygen is breathed at greater than normal partial pressures. This has led to protocols for avoidance of hypoxia being used in such fields as diving, hyperbaric therapy and human spaceflight. A human spaceflight is a Spaceflight with a human crew, and possibly passengers Although it may appear that hyperventilation might lead to hyperoxia, this does not happen since oxygen toxicity never occurs when breathing air at atmospheric pressure. In Medicine, hyperventilation (or overbreathing) is the state of Breathing faster and/or deeper than necessary bringing about lightheadedness and other
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Hyperoxia
Hyperoxia is excess oxygen in body tissues or higher than normal partial pressure of oxygen. Hyperoxia is caused by breathing gas at pressures greater than normal atmospheric pressure or by breathing oxygen-rich gases at normal atmospheric pressure for a prolonged period of time.
Mechanism
The high concentration of oxygen damages cells. [7] The precise mechanism(s) of the damage caused by these reactive oxygen species are not known, but oxygen gas has a propensity to react with certain metals to form superoxide which may attack double bonds in many organic systems, including the unsaturated fatty acid residues in cells. Reactive oxygen species (ROS are ions or very small molecules that include Oxygen Ions free radicals, and Peroxides both inorganic and Superoxide is the Anion O2&minus It is important as the product of the one-electron reduction of Dioxygen, which occurs widely in nature In Chemistry, especially Biochemistry, a fatty acid is a Carboxylic acid often with a long unbranched Aliphatic tail ( chain) which High concentrations of oxygen are known to increase the formation of free-radicals which harm DNA and other structures (see nitric oxide, peroxynitrite, and trioxidane). In Chemistry, radicals (often referred to as free radicals) are atoms molecules or ions with Unpaired electrons on an otherwise Open shell Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known Nitric oxide or nitrogen monoxide is a Chemical compound with Chemical formula N[[Oxygen O]] Peroxynitrite is the Anion with the formula ONOO− It is an unstable "valence isomer" of Nitrate, NO3− which has the Trioxidane, hydrogen trioxide or dihydrogen trioxide (H2O3 or HOOOH is an unstable molecule a type of hydrogen polyoxide which in Normally, the body has many defense systems against such damage (see glutathione, catalase, and superoxide dismutase) but at higher concentrations of free oxygen, these systems are eventually overwhelmed with time, and the rate of damage to cell membranes exceeds the capacity of systems which control or repair it. Glutathione ( GSH) is a Tripeptide. It contains an unusual Peptide linkage between the amine group of Cysteine and the Carboxyl Catalase is a common Enzyme found in nearly all living organisms where it functions to catalyze the decomposition of Hydrogen peroxide to The enzyme superoxide dismutase ( SOD,) catalyzes the Dismutation of Superoxide into Oxygen and Hydrogen peroxide. The cell membrane (also called the plasma membrane, plasmalemma, or "phospholipid bilayer" is a Selectively permeable Lipid bilayer Cell damage and cell death then results.
Types
In humans, there are several types of oxygen toxicity:[1][6]
- Central nervous system (CNS) oxygen toxicity
- Pulmonary oxygen toxicity
- Retinopathic oxygen toxicity
Central nervous system (CNS) oxygen toxicity
CNS oxygen toxicity manifests as symptoms such as visual changes, ringing in the ears, Nausea, twitching (especially on the face), irritability (personality changes, anxiety, confusion, etc. This article refers to the medical condition For the novel see Tunnel Vision; for the film see Tunnel Vision (film; for the mural "Tunnelvision" Tinnitus (tɪˈnaɪtəs or /ˈtɪnɪtəs/ from the Latin word for " Ringing " is the perception of sound within the human ear in the absence of corresponding Nausea ( Latin: Nausea, Greek:, " Sea-sickness " also called wamble) is the sensation of unease and discomfort ), dizziness, and convulsions. Vertigo (from the Latin vertere, to turn and the suffix -igo, a condition i An epileptic seizure is caused by excessive and/or hypersynchronous electrical Neuronal activity and is usually self-limiting [1][5] The onset depends upon partial pressure of oxygen (ppO2) in the breathing gas and exposure duration. Air is the most common and only natural breathing gas. Other artificial gases either pure gases or mixtures of gases are used in breathing equipment and enclosed habitats such
Background to CNS oxygen toxicity
CNS Toxicity was first described by Paul Bert in 1878. Year 1878 ( MDCCCLXXVIII) was a Common year starting on Tuesday (link will display the full calendar of the Gregorian calendar (or a Common [2] He showed that oxygen was toxic to insects, arachnids, myriapods, molluscs, earthworms, fungi, germinating seeds, birds, and other animals. Insects ( Class Insecta) are a major group of Arthropods and the most diverse group of Animals on the Earth with over a million described Arachnids are a class ( Arachnida) of joint-legged Invertebrate Animals in the subphylum Chelicerata. Myriapoda is a Subphylum of Arthropods containing Millipedes Centipedes and others Molluscs are animals belonging to the phylum Mollusca. There are around 250000 extant Species within the phylum with an estimated 70000 Earthworm is the usual name for the largest members of Oligochaeta (which is either a class or subclass depending on the author in the phylum Annelida In classical A fungus (ˈfʌŋgəs is a eukaryotic Organism that is a member of the kingdom Fungi (ˈfʌndʒaɪ Germination is the process whereby growth emerges from a period of dormancy Birds ( class Aves) are bipedal endothermic ( Warm-blooded) Vertebrate animals that lay eggs. The first recorded human exposure was recorded in 1910 by Bornstein when two men breathed oxygen at 2. Year 1910 ( MCMX) was a Common year starting on Saturday (link will display calendar of the Gregorian calendar (or a Common year starting 8 atm (280 kPa) for 30 minutes while he went on to 48 minutes with no symptoms. The Standard atmosphere is an international reference pressure defined as 101325 Pa and formerly used as unit of Pressure (symbol atm [16] In 1912, Bornstein developed cramps in his hands and legs while breathing oxygen at 2. Year 1912 ( MCMXII) was a Leap year starting on Monday (link will display the full calendar of the Gregorian calendar (or a Leap year starting 8 atm (280 kPa) for 51 minutes. [17] Behnke et. al. were the first to observe visual field contraction (tunnel vision) on dives between 1. The term visual field is sometimes used as a Synonym to Field of view, though they do not designate the same thing This article refers to the medical condition For the novel see Tunnel Vision; for the film see Tunnel Vision (film; for the mural "Tunnelvision" 0 atm (100 kPa) and 4. 0 atm (410 kPa). [18][19] During World War II, Donald and Yarbrough et. al. performed many studies on oxygen toxicity to support the initial use of closed circuit oxygen rebreathers. A rebreather is a type of Breathing set that provides a Breathing gas containing Oxygen and recycled exhaled gas [13][14][20][21] They discovered the effects of underwater immersion and exercise. In the decade following World War II, Lambertsen et. Christian James Lambertsen, MD, DSc (Hon (b 15 May, 1917) is an American environmental and Diving medicine al. made further discoveries on the effects of oxygen at pressure as well as methods of prevention. [22][23] In the years since, research on CNS toxicity has centered around methods of prevention and safe extension of tolerance. [24]
Clinical relevance of CNS oxygen toxicity
As CNS toxicity is caused by breathing oxygen at elevated ambient pressures, patients undergoing hyperbaric oxygen therapy are at risk of suffering hyperoxic seizures. [1][15][25] Treatment of seizures during treatment consists of removing the patient from oxygen, thereby dropping the partial pressure of oxygen delivered. [5]
Diving relevance of CNS oxygen toxicity
CNS oxygen toxicity is a deadly but entirely avoidable event while diving. The diver generally experiences no warning signs because the brain primarily monitors carbon dioxide levels. The symptoms are sudden convulsions and unconsciousness,[1][5] during which the victim can lose his/her regulator and drown. A diving regulator is a Pressure regulator used in a Scuba set that supplies the diver with breathing gas There is an increased risk of CNS oxygen toxicity on deep dives, long dives or dives where oxygen-rich breathing gases are used. Divers are taught to calculate a maximum operating depth for oxygen-rich breathing gases. In Technical diving, the maximum operating depth (MOD of a Breathing gas is the depth at which the Partial pressure of Oxygen (ppO2 Air is the most common and only natural breathing gas. Other artificial gases either pure gases or mixtures of gases are used in breathing equipment and enclosed habitats such Cylinders containing such mixtures must be clearly marked with that depth.
In some diver training courses for these types of diving, divers are taught to plan and monitor what is called the "oxygen clock" of their dives. Diver training is the process of developing skills and building experience in the use of Diving equipment and techniques so that the diver is able to dive safely and This clock is a notional alarm clock, which "ticks" more quickly at increased ppO2 and is set to activate at the maximum single exposure limits recommended in the NOAA Diving Manual. The National Oceanic and Atmospheric Administration ( NOAA) is a scientific agency within the United States Department of Commerce focused on the conditions of the The maximum single exposure limits recommended in the NOAA Diving Manual are 45 minutes at 1. The National Oceanic and Atmospheric Administration ( NOAA) is a scientific agency within the United States Department of Commerce focused on the conditions of the 6 bar (160 kPa), 120 minutes at 1. 5 bar (150 kPa), 150 minutes at 1. 4 bar (140 kPa), 180 minutes at 1. 3 bar (130 kPa) and 210 minutes at 1. 2 bar (120 kPa), but is impossible to predict with any reliability whether or when CNS symptoms will occur. [1][5][26][27] Many Nitrox-capable dive computers also calculate this "Oxygen Loading".
The aim is to avoid activating the alarm by reducing the ppO2 of the breathing gas or the length of time breathing gas of higher ppO2. As the ppO2 depends on the fraction of oxygen in the breathing gas and the depth of the dive, the diver can obtain more time on the oxygen clock by diving at a shallower depth, by breathing a less oxygen-rich gas or by shortening the exposure to oxygen-rich gases.
Pulmonary oxygen toxicity
Experimentally, early symptoms of breathing 100% oxygen are breathing difficulty and substernal pain or discomfort. The sternum (from Greek στέρνον sternon, "chest" or breastbone) is a long flat Bone located in the center of the thorax (chest The lungs show inflammation and pulmonary edema. Inflammation ( Latin, inflamatio, to set on fire is the complex biological response of vascular tissues to harmful stimuli such as Pathogens Pulmonary Edema (American English or oedema (British English is swelling and/or fluid accumulation in the Lungs It leads to impaired gas exchange and may cause [1][5]
Background to pulmonary oxygen toxicity
Pulmonary oxygen toxicity was first described by Lorrain Smith in 1899 when he noted CNS toxicity and discovered in experiments in mice and birds that 0. Year 1899 ( MDCCCXCIX) was a Common year starting on Sunday (link will display the full calendar of the Gregorian calendar (or a Common 42 atm (43 kPa) had no effect but 0. 74 atm (75 kPa) of oxygen was a pulmonary irritant. [4] He then went on to show that intermittent exposure permitted the lungs to recover and delayed the onset of toxicity. [4] Lambertsen et. Christian James Lambertsen, MD, DSc (Hon (b 15 May, 1917) is an American environmental and Diving medicine al. made further discoveries on the effects of oxygen effects at pressure as well as methods of prediction and prevention. [1][5][22] Their work on intermittent exposures for extension of oxygen tolerance[28] and model for prediction of pulmonary oxygen toxicity based on pulmonary function[29] are key documents in the development of operational oxygen procedures. In 1988, Hamilton et. Year 1988 ( MCMLXXXVIII) was a Leap year starting on Friday (link displays 1988 Gregorian calendar) al. wrote procedures for NOAA to establish oxygen exposure limits for habitat operations. The National Oceanic and Atmospheric Administration ( NOAA) is a scientific agency within the United States Department of Commerce focused on the conditions of the Underwater habitats are Underwater structures in which people can live for extended periods and carry out most of the basic human functions of a 24-hour day, such [1][30][31][32] Models for the prediction of pulmonary oxygen toxicity do not explain the results of all exposures to high partial pressures of oxygen. [33]
Clinical relevance of pulmonary oxygen toxicity
The risk of bronchopulmonary dysplasia ("BPD") in infants,[10][11] or adult respiratory distress syndrome in adults,[12] begins to increase with exposure for over 16 hours to oxygen partial pressures of 0. Bronchopulmonary dysplasia ( BPD; formerly Chronic Lung Disease of Infancy is a chronic Lung disorder that is most common among children who were born prematurely 5 bar (50 kPa) or more. At sea-level, 0. 5 bar (50 kPa) is exceeded by gas mixtures having oxygen fractions greater than 50%. Lung oxygen toxicity damage-rates at sea-level pressure rise non-linearly between the 50% threshold of toxicity, and the rate of damage on 100% oxygen. For this reason, intensive care patients requiring more than 60% oxygen, and especially patients at fractions near 100% oxygen, are considered to be at especially high risk. Intensive Care Medicine or critical care medicine is a branch of medicine concerned with the provision of Life support or organ support systems in patients If the situation is not corrected, the treatment may begin to cause lung damage which exacerbates the original problem requiring the high-oxygen mixture. Care must be used in distinguishing oxygen mole fraction from oxygen partial pressure. Partial pressures between 0. 2 bar (20 kPa) (normal at sea level) and 0. 5 bar (50 kPa) usually are considered non-toxic. BPD is reversible in the early stages during "break" periods on lower oxygen pressures, but it may eventually result in irreversible lung damage, if allowed to progress to severe damage. Usually several days of exposure without "oxygen breaks" are needed to cause severe lung damage.
Oxygen toxicity is a potential complication of mechanical ventilation with pure oxygen, where it is called the respiratory lung syndrome. In Medicine, mechanical ventilation is a method to mechanically assist or replace spontaneous breathing when patients cannot do so on their own
Diving relevance of pulmonary oxygen toxicity
Pulmonary oxygen toxicity is entirely avoidable event while diving. The time-factor and the naturally intermittent nature of most diving makes this a relatively rare (and even then, reversible) complication for divers. Guidelines have been established that allow divers to calculate when they are at risk of pulmonary toxicity. [1][5][28][30][31][32]
In the treatment of Decompression Sickness, divers are exposed to long periods of oxygen breathing under hyperbaric conditions. Decompression sickness (DCS, the diver’s disease, the bends, caisson disease is the name given to a variety of symptoms suffered by a person Hyperbaric medicine, also known as hyperbaric oxygen therapy (HBOT is the medical use of Oxygen at a higher than Atmospheric pressure. This exposure coupled with that from the dive that preceded the symptoms can be a significant cumulative oxygen exposure and pulmonary toxicity may occur. [15]
Space relevance of pulmonary oxygen toxicity
As noted earlier in this article, the toxicity is from high partial pressure. This is illustrated by oxygen use in spacesuits and other low-pressure applications (historically, for example, the Gemini spacecraft and Apollo spacecraft). Team The Gemini program was managed by the Manned Spacecraft Center Houston Texas under direction of the Office of Manned Space Flight NASA Headquarters Washington High fraction oxygen is non-toxic even at breathing mixture oxygen fractions approaching 100%, because the oxygen partial pressure is not allowed to chronically exceed 0. Chronic toxicity is a property of a substance that has Toxic effects on a living organism when that organism is exposed to the substance continuously or repeatedly 35 bar (35 kPa) in these applications.
Retinopathic oxygen toxicity
Prolonged exposure to high inspired fractions of oxygen causes damage to the retina. The vertebrate retina is a light sensitive part inside the inner layer of the Eye. Oxygen may be a contributing factor for the disorder called retrolental fibroplasia. Retinopathy of prematurity ( ROP) previously known as retrolental fibroplasia (RLF is a disease of the Eye that affects prematurely born babies [8] Hyperoxic myopia has occurred in closed circuit oxygen rebreather divers with prolonged exposures. Myopia (from Greek: μυωπία myopia "near-sightedness" also called near- or short-sightedness, is a refractive defect [9]
Hyperventilation
Oxygen toxicity is not a major factor in hyperventilating, as some people believe. In Medicine, hyperventilation (or overbreathing) is the state of Breathing faster and/or deeper than necessary bringing about lightheadedness and other The problems caused by hyperventilating are due to decreased carbon dioxide within the blood. Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single With or without hyperventilating, it is impossible to develop oxygen toxicity breathing air at typical surface atmospheric pressure. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five
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- ^ Vann RD (2004). "Lambertsen and O2: beginnings of operational physiology". Undersea Hyperb Med 31 (1): 21–31. PMID 15233157.
- ^ Natoli, M. J. and Vann R. D. (1996). Year 1996 ( MCMXCVI) was a Leap year starting on Monday (link will display full 1996 Gregorian calendar) Factors Affecting CNS Oxygen Toxicity in Humans Report to the US Office of Naval Research. Durham, NC: Duke University. Retrieved on 2008-04-29. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1429 - Joan of Arc arrives to relieve the Siege of Orleans.
- ^ Hampson NB, Simonson SG, Kramer CC, and Piantadosi CA (December 1996). "Central nervous system oxygen toxicity during hyperbaric treatment of patients with carbon monoxide poisoning". Undersea Hyperb Med 23 (4): 215–9. PMID 8989851.
- ^ Butler FK, Thalmann ED (June 1986). "Central nervous system oxygen toxicity in closed circuit scuba divers II". Undersea Biomed Res 13 (2): 193–223. PMID 3727183.
- ^ Butler FK (2004). "Closed-circuit oxygen diving in the U.S. Navy". Undersea Hyperb Med 31 (1): 3–20. PMID 15233156.
- ^ a b Clark JM (2004). "Extension of oxygen tolerance by interrupted exposure". Undersea Hyperb Med 31 (2): 195–8. PMID 15485080.
- ^ Clark, J. M. and Lambertsen, C. J. (1970). Year 1970 ( MCMLXX) was a Common year starting on Thursday (link shows full calendar of the Gregorian calendar. Pulmonary Oxygen Tolerance in Man and Derivation of Pulmonary Oxygen Tolerance Curves IFEM Report No. 1-70. Retrieved on 2008-04-29. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1429 - Joan of Arc arrives to relieve the Siege of Orleans.
- ^ a b Hamilton R. W. , Kenyon D. J. , Peterson R. E. , Butler G. J. , Beers D. M. (1988). Year 1988 ( MCMLXXXVIII) was a Leap year starting on Friday (link displays 1988 Gregorian calendar) Repex habitat diving procedures: Repetitive vertical excursions, oxygen limits, and surfacing techniques. Technical Report 88-1A. Retrieved on 2008-04-29. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1429 - Joan of Arc arrives to relieve the Siege of Orleans.
- ^ a b Hamilton R. W. , Kenyon D. J. , Peterson R. E. (1988). Year 1988 ( MCMLXXXVIII) was a Leap year starting on Friday (link displays 1988 Gregorian calendar) Repex habitat diving procedures: Repetitive vertical excursions, oxygen limits, and surfacing techniques. Technical Report 88-1B. Retrieved on 2008-04-29. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1429 - Joan of Arc arrives to relieve the Siege of Orleans.
- ^ a b Hamilton R. W. (1997). Year 1997 ( MCMXCVII) was a Common year starting on Wednesday (link will display full 1997 Gregorian calendar "Tolerating oxygen exposure". South Pacific Underwater Medicine Society journal 27 (1). ISSN 0813-1988. An International Standard Serial Number ( ISSN) is a unique eight-digit number used to identify a print or electronic Periodical publication. OCLC 16986801. The OCLC Online Computer Library Center is according to its website a "nonprofit membership computer library service and research organization dedicated to the public purpose
- ^ Shykoff, B (2007). Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Performance of Various Models in Predicting Vital Capacity Changes Caused by Breathing High Oxygen Partial Pressures. NEDU-TR-07-13. Retrieved on 2008-06-06. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 1508 - Maximilian I Holy Roman Emperor, is defeated in Friulia by Venetian forces; he is forced to sign a three-year
Additional References
- Scubadoc's Diving Medicine Online[1]
- The Diving Emergency Handbook, John Lippmann and Stan Bugg, ISBN 0-946020-18-3
External links
- Undersea and Hyperbaric Medical Society Scientific body, publications about Oxygen Toxicity
- Rubicon Research Repository Online collection of the UHMS published journal articles, free content
- Physiology at MCG 4/4ch7/s4ch7_7
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