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[¹oxy- + -gen]
SYMB: O A colorless, odorless, tasteless, gaseous chemical element, atomic weight (mass) 15.9994, atomic number 8. It occurs free in the atmosphere and makes up approx. 21% of the volume of the atmosphere. Oxygen is a constitutent of animal, vegetable, and mineral substances and is essential to respiration for most living organisms. At sea level, oxygen represents 10% to 16% of venous blood and 17% to 21% of arterial blood.
Oxygen is absorbed by most living organisms. During photosynthesis it is produced by green plants from carbon dioxide and water. When oxygen is used in cell respiration, the end products are water and carbon dioxide; the carbon dioxide is returned to the atmosphere.
Oxygen combines readily with other elements to form oxides. When oxygen combines with another substance, the process is called oxidation. When combination takes place rapidly enough to produce light and heat, the combination is called combustion.
Oxygen is used medicinally to manage anemia, bleeding, ischemia, shock, pulmonary edema, pneumonia, respiratory distress, ventilatory failure, obstructive lung diseases, pulmonary embolism, myocardial infarction, mountain sickness, smoke inhalation, carbon monoxide or cyanide poisoning, and gangrene, where oxygen is temporarily or chronically insufficient. Oxygen is administered by mask, nasal tube, tent, or in an airtight chamber in which pressure may be increased. No matter how much oxygen is given, it is important to have it adequately humidified. It is desirable to administer oxygen at whatever rate is necessary to increase the oxygen content of inspired air to 50%.
SEE: hypoxia; SEE: oxygen therapy