Oxygen toxicity or oxygen toxicity syndrome is severe hyperoxia caused by breathing oxygen at elevated partial pressures. The high concentration of oxygen damages cells. General Name, Symbol, Number oxygen, O, 8 Chemical series Chalcogens Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... The partial pressure of a gas in a mixture or solution is what the pressure of that gas would be if all other components of the mixture or solution suddenly vanished without its temperature changing. ... Concentration is a very common concept used in chemistry and related fields. ... Cells in culture, stained for keratin (red) and DNA (green) The cell is the structural and functional unit of all living organisms, and are sometimes called the building blocks of life. ...

Hyperoxia

Hyperoxia is excess oxygen in body tissues or higher than normal partial pressure of oxygen. Hyperoxia is caused by breathing air at pressures greater than normal atmospheric pressure or by breathing nitrox or oxygen at normal atmospheric pressure for a prolonged period of time. The partial pressure of a gas in a mixture or solution is what the pressure of that gas would be if all other components of the mixture or solution suddenly vanished without its temperature changing. ... diurnal (daily) rhythm of air pressure in northern Germany (black curve is air pressure) Atmospheric pressure is the pressure above any area in the Earths atmosphere caused by the weight of air. ...

Common causes

The oxygen toxicity syndrome may occur

• as a diving disorder, when divers breathe any breathing gas at the high pressure of depth,
• as a potential complication of mechanical ventilation with pure oxygen, where it is called the respiratory lung syndrome.

Oxygen toxicity is not a major factor in hyperventilating, as some people believe. The problems caused by hyperventilating are due to decreased carbon dioxide within the blood. With or without hyperventilating, it is impossible to develop oxygen toxicity breathing air at typical surface atmospheric pressure. Divers face specific physical and health risks when they go underwater (e. ... Air is the most common and only natural breathing gas. ... ventilation balloon In medicine, mechanical ventilation is a method to assist or replace spontaneous breathing. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Chalcogens Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... In medicine, hyperventilation is the state of breathing faster or deeper than necessary, and thereby reducing the carbon dioxide concentration of the blood below normal. ... Carbon dioxide is an atmospheric gas comprised of one carbon and two oxygen atoms. ... Air is a name for the mixture of gases present in the Earths atmosphere. ... diurnal (daily) rhythm of air pressure in northern Germany (black curve is air pressure) Atmospheric pressure is the pressure above any area in the Earths atmosphere caused by the weight of air. ...

Types of oxygen toxicity

In humans, there are several types of oxygen toxicity:

• Central nervous system (CNS) oxygen toxicity is manifested as convulsions, which although not lethal themselves, can cause drowning of divers or lethal pressure damage during a rapid ascent.

The likelihood of this type of accident is directly proportional to the partial pressure of oxygen (ppO₂) in the breathing gas and to the duration of exposure. A diagram showing the CNS. The central nervous system (CNS) represents the largest part of the nervous system. ... This article is about the medical term, epileptic seizure, as distinct from psychogenic non-epileptic seizure. ... Barotrauma is physical damage to body tissues caused by a difference in pressure between an air space inside or beside the body and the surrounding gas or liquid. ...

• Pulmonary oxygen toxicity is caused by exposure over 16 hours to partial pressures of 0.5 bar or more. The damage to the lungs may be irreversible. This is rare complication in divers, but may be of concern in intensive care patients needing high inspired oxygen concentrations.
• Retinopathic oxygen toxicity causes damage to the retina. Oxygen may be a contributing factor for the disorder called retinopathy of prematurity.

... Intensive care medicine or critical care medicine is concerned with providing greater than ordinary medical care and observation to people in a critical or unstable condition. ... Human eye cross-sectional view. ... Retinopathy of prematurity (ROP) is a disease of the eye that affects prematurely born babies. ...

Avoiding oxygen toxicity while diving

There is an increased risk of CNS oxygen toxicity on deep dives, long dives or dives where oxygen-rich breathing gases are used. Air is the most common and only natural breathing gas. ...

Divers are taught, in some diver training courses for these types of diving, to plan and monitor what is called the "oxygen clock" of their dives. This clock is a notional alarm clock, which "ticks" more quickly at increased ppO2 and is set to activate at these maximum single exposure limits recommended in the NOAA Diving Manual: 45 minutes at 1.6 bar, of 120 minutes at 1.5 bar, of 150 minutes at 1.4 bar and of 180 minutes at 1.3 bar. Diver training is essential for safe diving. ... The National Oceanic and Atmospheric Administration (NOAA) is a scientific agency of the United States Department of Commerce focused on the conditions of the oceans and the atmosphere. ... A bar (symbol bar) is a unit of pressure. ...

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 oxygen concentration 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.

See also

• Hypoxia (medical)