A colourless, odourless gas that makes up 21 per cent of the Earth’s atmosphere. Oxygen is essential for almost all forms of life, including humans, because it is necessary for the metabolic “burning” of foods to produce energy – a process that takes place in body cells and is known as aerobic metabolism.
Oxygen is absorbed through the lungs and into the blood, where it binds to the haemoglobin in red blood cells. As oxygen-rich blood circulates around the body, the oxygen is released from the red blood cells into the body tissues.
Additional supplies of oxygen are used to treat conditions such as severe bronchitis or hypoxia. High-pressure oxygen (see hyperbaric oxygen treatment) is sometimes used to treat decompression sickness or carbon monoxide poisoning.
(See also ozone.)
A colourless and odourless gas of molecular weight 32. It constitutes just less than 21 per cent of the earth’s atmosphere. As a medical gas, it is supplied in the UK compressed at high pressure (13,600 kilopascals (KPa)) in cylinders which are black with white shoulders. In hospitals, oxygen is often stored as a liquid in insulated tanks and controlled evaporation allows the gas to be supplied via a pipeline at a much lower pressure.
Oxygen is essential for life. It is absorbed via the lungs (see RESPIRATION) and is transported by HAEMOGLOBIN within the ERYTHROCYTES to the tissues. Within the individual cell it is involved in the production of adenosine triphosphate (ATP), a compound that stores chemical energy for muscle cells, by the oxidative metabolism of fats and carbohydrates. HYPOXIA causes anaerobic metabolism with a resulting build-up in LACTIC ACID, the result of muscle cell activity. If severe enough, the lack of ATP causes a breakdown in cellular function and the death of the individual.
When hypoxia occurs, it may be corrected by giving supplemental oxygen. This is usually given via a face mask or nasal prongs or, in severe cases, during ARTIFICIAL VENTILATION OF THE LUNGS. Some indications for oxygen therapy are high altitude, ventilatory failure, heart failure, ANAEMIA, PULMONARY HYPERTENSION, CARBON MONOXIDE (CO) poisoning, anaesthesia and post-operative recovery. In some conditions – e.g. severe infections with anaerobic bacteria and CO poisoning – hyperbaric oxygen therapy has been used.
n. an odourless colourless gas that makes up one-fifth of the atmosphere. Oxygen is essential to most forms of life in that it combines chemically with glucose (or some other fuel) to provide energy for metabolic processes. It is absorbed into the blood from air breathed into the lungs. Oxygen is administered therapeutically in various conditions in which the tissues are unable to obtain an adequate supply through the lungs (see oxygenator; tent). Symbol: O.
A sheet of plastic put over a hospital bed with OXYGEN fed into it so that a patient can receive oxygen. Such treatment may be for a heart or lung condition in which the normal atmospheric concentration of oxygen is insu?cient to enable the person to oxygenate the blood ?owing through the lungs to a normal level, so extra oxygen is provided in the patient’s immediate surroundings.... oxygen tent
OXYGEN toxicity in human lungs causes an acute OEDEMA followed by ?brosis and PULMONARY HYPERTENSION. In the neonate, retrolental ?broplasia occurs and centralnervous-system damage may result in the infant having ?ts. Several factors are involved in toxicity and there is no absolute relationship to time or concentration, although inspired concentrations of under 50 per cent are probably safe for long periods.... oxygen toxicity
An appliance used in oxygen therapy that separates oxygen from the air and mixes it back in at a greater concentration. This oxygenenriched air is delivered through a tube for prolonged inhalation. The appliance is used by people who have persistent hypoxia due to severe chronic obstructive pulmonary disease (see pulmonary disease, chronic obstructive). (See also hyperbaric oxygen treatment.)... oxygen concentrator
a technique for exposing a patient to oxygen at a pressure of greater than 1 atmosphere in a compression chamber. It is used to treat carbon monoxide poisoning, gas gangrene, compressed air illness, and acute breathing difficulties. It is also used in some cases during heart surgery. In dental extractions and implant treatment it may reduce the incidence of osteonecrosis in patients who have received radiation to the head and neck region (osteoradionecrosis).... hyperbaric oxygenation
a physiological condition that exists in cells during periods of temporary oxygen shortage. During periods of violent exertion the body requires extra energy, which is obtained by the breakdown of glucose in the absence of oxygen, after the available oxygen has been used up. The breakdown products are acidic and cause muscle pain. The oxygen required to get rid of the breakdown products (called the oxygen deficit) must be made available after the exertion stops.... oxygen deficit
Health Encyclopedia